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xmlregexp.c

/*
 * regexp.c: generic and extensible Regular Expression engine
 *
 * Basically designed with the purpose of compiling regexps for 
 * the variety of validation/shemas mechanisms now available in
 * XML related specifications these include:
 *    - XML-1.0 DTD validation
 *    - XML Schemas structure part 1
 *    - XML Schemas Datatypes part 2 especially Appendix F
 *    - RELAX-NG/TREX i.e. the counter proposal
 *
 * See Copyright for the status of this software.
 *
 * Daniel Veillard <veillard@redhat.com>
 */

#define IN_LIBXML
#include "libxml.h"

#ifdef LIBXML_REGEXP_ENABLED

/* #define DEBUG_ERR */

#include <stdio.h>
#include <string.h>
#ifdef HAVE_LIMITS_H
#include <limits.h>
#endif

#include <libxml/tree.h>
#include <libxml/parserInternals.h>
#include <libxml/xmlregexp.h>
#include <libxml/xmlautomata.h>
#include <libxml/xmlunicode.h>

#ifndef INT_MAX
#define INT_MAX 123456789 /* easy to flag and big enough for our needs */
#endif

/* #define DEBUG_REGEXP_GRAPH */
/* #define DEBUG_REGEXP_EXEC */
/* #define DEBUG_PUSH */
/* #define DEBUG_COMPACTION */

#define MAX_PUSH 10000000

#define ERROR(str)                                          \
    ctxt->error = XML_REGEXP_COMPILE_ERROR;                       \
    xmlRegexpErrCompile(ctxt, str);
#define NEXT ctxt->cur++
#define CUR (*(ctxt->cur))
#define NXT(index) (ctxt->cur[index])

#define CUR_SCHAR(s, l) xmlStringCurrentChar(NULL, s, &l)
#define NEXTL(l) ctxt->cur += l;
#define XML_REG_STRING_SEPARATOR '|'
/*
 * Need PREV to check on a '-' within a Character Group. May only be used
 * when it's guaranteed that cur is not at the beginning of ctxt->string!
 */
#define PREV (ctxt->cur[-1])

/**
 * TODO:
 *
 * macro to flag unimplemented blocks
 */
#define TODO                                                \
    xmlGenericError(xmlGenericErrorContext,                       \
          "Unimplemented block at %s:%d\n",                       \
            __FILE__, __LINE__);

/************************************************************************
 *                                                    *
 *                Datatypes and structures                  *
 *                                                    *
 ************************************************************************/

/*
 * Note: the order of the enums below is significant, do not shuffle
 */
typedef enum {
    XML_REGEXP_EPSILON = 1,
    XML_REGEXP_CHARVAL,
    XML_REGEXP_RANGES,
    XML_REGEXP_SUBREG,  /* used for () sub regexps */
    XML_REGEXP_STRING,
    XML_REGEXP_ANYCHAR, /* . */
    XML_REGEXP_ANYSPACE, /* \s */
    XML_REGEXP_NOTSPACE, /* \S */
    XML_REGEXP_INITNAME, /* \l */
    XML_REGEXP_NOTINITNAME, /* \L */
    XML_REGEXP_NAMECHAR, /* \c */
    XML_REGEXP_NOTNAMECHAR, /* \C */
    XML_REGEXP_DECIMAL, /* \d */
    XML_REGEXP_NOTDECIMAL, /* \D */
    XML_REGEXP_REALCHAR, /* \w */
    XML_REGEXP_NOTREALCHAR, /* \W */
    XML_REGEXP_LETTER = 100,
    XML_REGEXP_LETTER_UPPERCASE,
    XML_REGEXP_LETTER_LOWERCASE,
    XML_REGEXP_LETTER_TITLECASE,
    XML_REGEXP_LETTER_MODIFIER,
    XML_REGEXP_LETTER_OTHERS,
    XML_REGEXP_MARK,
    XML_REGEXP_MARK_NONSPACING,
    XML_REGEXP_MARK_SPACECOMBINING,
    XML_REGEXP_MARK_ENCLOSING,
    XML_REGEXP_NUMBER,
    XML_REGEXP_NUMBER_DECIMAL,
    XML_REGEXP_NUMBER_LETTER,
    XML_REGEXP_NUMBER_OTHERS,
    XML_REGEXP_PUNCT,
    XML_REGEXP_PUNCT_CONNECTOR,
    XML_REGEXP_PUNCT_DASH,
    XML_REGEXP_PUNCT_OPEN,
    XML_REGEXP_PUNCT_CLOSE,
    XML_REGEXP_PUNCT_INITQUOTE,
    XML_REGEXP_PUNCT_FINQUOTE,
    XML_REGEXP_PUNCT_OTHERS,
    XML_REGEXP_SEPAR,
    XML_REGEXP_SEPAR_SPACE,
    XML_REGEXP_SEPAR_LINE,
    XML_REGEXP_SEPAR_PARA,
    XML_REGEXP_SYMBOL,
    XML_REGEXP_SYMBOL_MATH,
    XML_REGEXP_SYMBOL_CURRENCY,
    XML_REGEXP_SYMBOL_MODIFIER,
    XML_REGEXP_SYMBOL_OTHERS,
    XML_REGEXP_OTHER,
    XML_REGEXP_OTHER_CONTROL,
    XML_REGEXP_OTHER_FORMAT,
    XML_REGEXP_OTHER_PRIVATE,
    XML_REGEXP_OTHER_NA,
    XML_REGEXP_BLOCK_NAME
} xmlRegAtomType;

typedef enum {
    XML_REGEXP_QUANT_EPSILON = 1,
    XML_REGEXP_QUANT_ONCE,
    XML_REGEXP_QUANT_OPT,
    XML_REGEXP_QUANT_MULT,
    XML_REGEXP_QUANT_PLUS,
    XML_REGEXP_QUANT_ONCEONLY,
    XML_REGEXP_QUANT_ALL,
    XML_REGEXP_QUANT_RANGE
} xmlRegQuantType;

typedef enum {
    XML_REGEXP_START_STATE = 1,
    XML_REGEXP_FINAL_STATE,
    XML_REGEXP_TRANS_STATE,
    XML_REGEXP_SINK_STATE,
    XML_REGEXP_UNREACH_STATE
} xmlRegStateType;

typedef enum {
    XML_REGEXP_MARK_NORMAL = 0,
    XML_REGEXP_MARK_START,
    XML_REGEXP_MARK_VISITED
} xmlRegMarkedType;

typedef struct _xmlRegRange xmlRegRange;
typedef xmlRegRange *xmlRegRangePtr;

struct _xmlRegRange {
    int neg;            /* 0 normal, 1 not, 2 exclude */
    xmlRegAtomType type;
    int start;
    int end;
    xmlChar *blockName;
};

typedef struct _xmlRegAtom xmlRegAtom;
typedef xmlRegAtom *xmlRegAtomPtr;

typedef struct _xmlAutomataState xmlRegState;
typedef xmlRegState *xmlRegStatePtr;

struct _xmlRegAtom {
    int no;
    xmlRegAtomType type;
    xmlRegQuantType quant;
    int min;
    int max;

    void *valuep;
    void *valuep2;
    int neg;
    int codepoint;
    xmlRegStatePtr start;
    xmlRegStatePtr start0;
    xmlRegStatePtr stop;
    int maxRanges;
    int nbRanges;
    xmlRegRangePtr *ranges;
    void *data;
};

typedef struct _xmlRegCounter xmlRegCounter;
typedef xmlRegCounter *xmlRegCounterPtr;

struct _xmlRegCounter {
    int min;
    int max;
};

typedef struct _xmlRegTrans xmlRegTrans;
typedef xmlRegTrans *xmlRegTransPtr;

struct _xmlRegTrans {
    xmlRegAtomPtr atom;
    int to;
    int counter;
    int count;
    int nd;
};

struct _xmlAutomataState {
    xmlRegStateType type;
    xmlRegMarkedType mark;
    xmlRegMarkedType reached;
    int no;
    int maxTrans;
    int nbTrans;
    xmlRegTrans *trans;
    /*  knowing states ponting to us can speed things up */
    int maxTransTo;
    int nbTransTo;
    int *transTo;
};

typedef struct _xmlAutomata xmlRegParserCtxt;
typedef xmlRegParserCtxt *xmlRegParserCtxtPtr;

struct _xmlAutomata {
    xmlChar *string;
    xmlChar *cur;

    int error;
    int neg;

    xmlRegStatePtr start;
    xmlRegStatePtr end;
    xmlRegStatePtr state;

    xmlRegAtomPtr atom;

    int maxAtoms;
    int nbAtoms;
    xmlRegAtomPtr *atoms;

    int maxStates;
    int nbStates;
    xmlRegStatePtr *states;

    int maxCounters;
    int nbCounters;
    xmlRegCounter *counters;

    int determinist;
    int negs;
};

struct _xmlRegexp {
    xmlChar *string;
    int nbStates;
    xmlRegStatePtr *states;
    int nbAtoms;
    xmlRegAtomPtr *atoms;
    int nbCounters;
    xmlRegCounter *counters;
    int determinist;
    /*
     * That's the compact form for determinists automatas
     */
    int nbstates;
    int *compact;
    void **transdata;
    int nbstrings;
    xmlChar **stringMap;
};

typedef struct _xmlRegExecRollback xmlRegExecRollback;
typedef xmlRegExecRollback *xmlRegExecRollbackPtr;

struct _xmlRegExecRollback {
    xmlRegStatePtr state;/* the current state */
    int index;          /* the index in the input stack */
    int nextbranch;     /* the next transition to explore in that state */
    int *counts;  /* save the automata state if it has some */
};

typedef struct _xmlRegInputToken xmlRegInputToken;
typedef xmlRegInputToken *xmlRegInputTokenPtr;

struct _xmlRegInputToken {
    xmlChar *value;
    void *data;
};

struct _xmlRegExecCtxt {
    int status;         /* execution status != 0 indicate an error */
    int determinist;    /* did we find an indeterministic behaviour */
    xmlRegexpPtr comp;  /* the compiled regexp */
    xmlRegExecCallbacks callback;
    void *data;

    xmlRegStatePtr state;/* the current state */
    int transno;  /* the current transition on that state */
    int transcount;     /* the number of chars in char counted transitions */

    /*
     * A stack of rollback states
     */
    int maxRollbacks;
    int nbRollbacks;
    xmlRegExecRollback *rollbacks;

    /*
     * The state of the automata if any
     */
    int *counts;

    /*
     * The input stack
     */
    int inputStackMax;
    int inputStackNr;
    int index;
    int *charStack;
    const xmlChar *inputString; /* when operating on characters */
    xmlRegInputTokenPtr inputStack;/* when operating on strings */

    /*
     * error handling
     */
    int errStateNo;           /* the error state number */
    xmlRegStatePtr errState;    /* the error state */
    xmlChar *errString;       /* the string raising the error */
    int *errCounts;           /* counters at the error state */
    int nbPush;
};

#define REGEXP_ALL_COUNTER    0x123456
#define REGEXP_ALL_LAX_COUNTER      0x123457

static void xmlFAParseRegExp(xmlRegParserCtxtPtr ctxt, int top);
static void xmlRegFreeState(xmlRegStatePtr state);
static void xmlRegFreeAtom(xmlRegAtomPtr atom);
static int xmlRegStrEqualWildcard(const xmlChar *expStr, const xmlChar *valStr);
static int xmlRegCheckCharacter(xmlRegAtomPtr atom, int codepoint);
static int xmlRegCheckCharacterRange(xmlRegAtomType type, int codepoint,
                  int neg, int start, int end, const xmlChar *blockName);

/************************************************************************
 *                                                    *
 *          Regexp memory error handler                     *
 *                                                    *
 ************************************************************************/
/**
 * xmlRegexpErrMemory:
 * @extra:  extra information
 *
 * Handle an out of memory condition
 */
static void
xmlRegexpErrMemory(xmlRegParserCtxtPtr ctxt, const char *extra)
{
    const char *regexp = NULL;
    if (ctxt != NULL) {
        regexp = (const char *) ctxt->string;
      ctxt->error = XML_ERR_NO_MEMORY;
    }
    __xmlRaiseError(NULL, NULL, NULL, NULL, NULL, XML_FROM_REGEXP,
                XML_ERR_NO_MEMORY, XML_ERR_FATAL, NULL, 0, extra,
                regexp, NULL, 0, 0,
                "Memory allocation failed : %s\n", extra);
}

/**
 * xmlRegexpErrCompile:
 * @extra:  extra information
 *
 * Handle a compilation failure
 */
static void
xmlRegexpErrCompile(xmlRegParserCtxtPtr ctxt, const char *extra)
{
    const char *regexp = NULL;
    int idx = 0;

    if (ctxt != NULL) {
        regexp = (const char *) ctxt->string;
      idx = ctxt->cur - ctxt->string;
      ctxt->error = XML_REGEXP_COMPILE_ERROR;
    }
    __xmlRaiseError(NULL, NULL, NULL, NULL, NULL, XML_FROM_REGEXP,
                XML_REGEXP_COMPILE_ERROR, XML_ERR_FATAL, NULL, 0, extra,
                regexp, NULL, idx, 0,
                "failed to compile: %s\n", extra);
}

/************************************************************************
 *                                                    *
 *                Allocation/Deallocation                   *
 *                                                    *
 ************************************************************************/

static int xmlFAComputesDeterminism(xmlRegParserCtxtPtr ctxt);
/**
 * xmlRegEpxFromParse:
 * @ctxt:  the parser context used to build it
 *
 * Allocate a new regexp and fill it with the result from the parser
 *
 * Returns the new regexp or NULL in case of error
 */
static xmlRegexpPtr
xmlRegEpxFromParse(xmlRegParserCtxtPtr ctxt) {
    xmlRegexpPtr ret;

    ret = (xmlRegexpPtr) xmlMalloc(sizeof(xmlRegexp));
    if (ret == NULL) {
      xmlRegexpErrMemory(ctxt, "compiling regexp");
      return(NULL);
    }
    memset(ret, 0, sizeof(xmlRegexp));
    ret->string = ctxt->string;
    ret->nbStates = ctxt->nbStates;
    ret->states = ctxt->states;
    ret->nbAtoms = ctxt->nbAtoms;
    ret->atoms = ctxt->atoms;
    ret->nbCounters = ctxt->nbCounters;
    ret->counters = ctxt->counters;
    ret->determinist = ctxt->determinist;
    if (ret->determinist == -1) {
        xmlRegexpIsDeterminist(ret);
    }

    if ((ret->determinist != 0) &&
      (ret->nbCounters == 0) &&
      (ctxt->negs == 0) &&
      (ret->atoms != NULL) &&
      (ret->atoms[0] != NULL) &&
      (ret->atoms[0]->type == XML_REGEXP_STRING)) {
      int i, j, nbstates = 0, nbatoms = 0;
      int *stateRemap;
      int *stringRemap;
      int *transitions;
      void **transdata;
      xmlChar **stringMap;
        xmlChar *value;

      /*
       * Switch to a compact representation
       * 1/ counting the effective number of states left
       * 2/ counting the unique number of atoms, and check that
       *    they are all of the string type
       * 3/ build a table state x atom for the transitions
       */

      stateRemap = xmlMalloc(ret->nbStates * sizeof(int));
      if (stateRemap == NULL) {
          xmlRegexpErrMemory(ctxt, "compiling regexp");
          xmlFree(ret);
          return(NULL);
      }
      for (i = 0;i < ret->nbStates;i++) {
          if (ret->states[i] != NULL) {
            stateRemap[i] = nbstates;
            nbstates++;
          } else {
            stateRemap[i] = -1;
          }
      }
#ifdef DEBUG_COMPACTION
      printf("Final: %d states\n", nbstates);
#endif
      stringMap = xmlMalloc(ret->nbAtoms * sizeof(char *));
      if (stringMap == NULL) {
          xmlRegexpErrMemory(ctxt, "compiling regexp");
          xmlFree(stateRemap);
          xmlFree(ret);
          return(NULL);
      }
      stringRemap = xmlMalloc(ret->nbAtoms * sizeof(int));
      if (stringRemap == NULL) {
          xmlRegexpErrMemory(ctxt, "compiling regexp");
          xmlFree(stringMap);
          xmlFree(stateRemap);
          xmlFree(ret);
          return(NULL);
      }
      for (i = 0;i < ret->nbAtoms;i++) {
          if ((ret->atoms[i]->type == XML_REGEXP_STRING) &&
            (ret->atoms[i]->quant == XML_REGEXP_QUANT_ONCE)) {
            value = ret->atoms[i]->valuep;
                for (j = 0;j < nbatoms;j++) {
                if (xmlStrEqual(stringMap[j], value)) {
                  stringRemap[i] = j;
                  break;
                }
            }
            if (j >= nbatoms) {
                stringRemap[i] = nbatoms;
                stringMap[nbatoms] = xmlStrdup(value);
                if (stringMap[nbatoms] == NULL) {
                  for (i = 0;i < nbatoms;i++)
                      xmlFree(stringMap[i]);
                  xmlFree(stringRemap);
                  xmlFree(stringMap);
                  xmlFree(stateRemap);
                  xmlFree(ret);
                  return(NULL);
                }
                nbatoms++;
            }
          } else {
            xmlFree(stateRemap);
            xmlFree(stringRemap);
            for (i = 0;i < nbatoms;i++)
                xmlFree(stringMap[i]);
            xmlFree(stringMap);
            xmlFree(ret);
            return(NULL);
          }
      }
#ifdef DEBUG_COMPACTION
      printf("Final: %d atoms\n", nbatoms);
#endif
      transitions = (int *) xmlMalloc((nbstates + 1) *
                                      (nbatoms + 1) * sizeof(int));
      if (transitions == NULL) {
          xmlFree(stateRemap);
          xmlFree(stringRemap);
          xmlFree(stringMap);
          xmlFree(ret);
          return(NULL);
      }
      memset(transitions, 0, (nbstates + 1) * (nbatoms + 1) * sizeof(int));

      /*
       * Allocate the transition table. The first entry for each
       * state corresponds to the state type.
       */
      transdata = NULL;

      for (i = 0;i < ret->nbStates;i++) {
          int stateno, atomno, targetno, prev;
          xmlRegStatePtr state;
          xmlRegTransPtr trans;

          stateno = stateRemap[i];
          if (stateno == -1)
            continue;
          state = ret->states[i];

          transitions[stateno * (nbatoms + 1)] = state->type;

          for (j = 0;j < state->nbTrans;j++) {
            trans = &(state->trans[j]);
            if ((trans->to == -1) || (trans->atom == NULL))
                continue;
                atomno = stringRemap[trans->atom->no];
            if ((trans->atom->data != NULL) && (transdata == NULL)) {
                transdata = (void **) xmlMalloc(nbstates * nbatoms *
                                              sizeof(void *));
                if (transdata != NULL)
                  memset(transdata, 0,
                         nbstates * nbatoms * sizeof(void *));
                else {
                  xmlRegexpErrMemory(ctxt, "compiling regexp");
                  break;
                }
            }
            targetno = stateRemap[trans->to];
            /*
             * if the same atom can generate transitions to 2 different
             * states then it means the automata is not determinist and
             * the compact form can't be used !
             */
            prev = transitions[stateno * (nbatoms + 1) + atomno + 1];
            if (prev != 0) {
                if (prev != targetno + 1) {
                  ret->determinist = 0;
#ifdef DEBUG_COMPACTION
                  printf("Indet: state %d trans %d, atom %d to %d : %d to %d\n",
                         i, j, trans->atom->no, trans->to, atomno, targetno);
                  printf("       previous to is %d\n", prev);
#endif
                  if (transdata != NULL)
                      xmlFree(transdata);
                  xmlFree(transitions);
                  xmlFree(stateRemap);
                  xmlFree(stringRemap);
                  for (i = 0;i < nbatoms;i++)
                      xmlFree(stringMap[i]);
                  xmlFree(stringMap);
                  goto not_determ;
                }
            } else {
#if 0
                printf("State %d trans %d: atom %d to %d : %d to %d\n",
                     i, j, trans->atom->no, trans->to, atomno, targetno);
#endif
                transitions[stateno * (nbatoms + 1) + atomno + 1] =
                  targetno + 1; /* to avoid 0 */
                if (transdata != NULL)
                  transdata[stateno * nbatoms + atomno] =
                      trans->atom->data;
            }
          }
      }
      ret->determinist = 1;
#ifdef DEBUG_COMPACTION
      /*
       * Debug
       */
      for (i = 0;i < nbstates;i++) {
          for (j = 0;j < nbatoms + 1;j++) {
                printf("%02d ", transitions[i * (nbatoms + 1) + j]);
          }
          printf("\n");
      }
      printf("\n");
#endif
      /*
       * Cleanup of the old data
       */
      if (ret->states != NULL) {
          for (i = 0;i < ret->nbStates;i++)
            xmlRegFreeState(ret->states[i]);
          xmlFree(ret->states);
      }
      ret->states = NULL;
      ret->nbStates = 0;
      if (ret->atoms != NULL) {
          for (i = 0;i < ret->nbAtoms;i++)
            xmlRegFreeAtom(ret->atoms[i]);
          xmlFree(ret->atoms);
      }
      ret->atoms = NULL;
      ret->nbAtoms = 0;

      ret->compact = transitions;
      ret->transdata = transdata;
      ret->stringMap = stringMap;
      ret->nbstrings = nbatoms;
      ret->nbstates = nbstates;
      xmlFree(stateRemap);
      xmlFree(stringRemap);
    }
not_determ:
    ctxt->string = NULL;
    ctxt->nbStates = 0;
    ctxt->states = NULL;
    ctxt->nbAtoms = 0;
    ctxt->atoms = NULL;
    ctxt->nbCounters = 0;
    ctxt->counters = NULL;
    return(ret);
}

/**
 * xmlRegNewParserCtxt:
 * @string:  the string to parse
 *
 * Allocate a new regexp parser context
 *
 * Returns the new context or NULL in case of error
 */
static xmlRegParserCtxtPtr
xmlRegNewParserCtxt(const xmlChar *string) {
    xmlRegParserCtxtPtr ret;

    ret = (xmlRegParserCtxtPtr) xmlMalloc(sizeof(xmlRegParserCtxt));
    if (ret == NULL)
      return(NULL);
    memset(ret, 0, sizeof(xmlRegParserCtxt));
    if (string != NULL)
      ret->string = xmlStrdup(string);
    ret->cur = ret->string;
    ret->neg = 0;
    ret->negs = 0;
    ret->error = 0;
    ret->determinist = -1;
    return(ret);
}

/**
 * xmlRegNewRange:
 * @ctxt:  the regexp parser context
 * @neg:  is that negative
 * @type:  the type of range
 * @start:  the start codepoint
 * @end:  the end codepoint
 *
 * Allocate a new regexp range
 *
 * Returns the new range or NULL in case of error
 */
static xmlRegRangePtr
xmlRegNewRange(xmlRegParserCtxtPtr ctxt,
             int neg, xmlRegAtomType type, int start, int end) {
    xmlRegRangePtr ret;

    ret = (xmlRegRangePtr) xmlMalloc(sizeof(xmlRegRange));
    if (ret == NULL) {
      xmlRegexpErrMemory(ctxt, "allocating range");
      return(NULL);
    }
    ret->neg = neg;
    ret->type = type;
    ret->start = start;
    ret->end = end;
    return(ret);
}

/**
 * xmlRegFreeRange:
 * @range:  the regexp range
 *
 * Free a regexp range
 */
static void
xmlRegFreeRange(xmlRegRangePtr range) {
    if (range == NULL)
      return;

    if (range->blockName != NULL)
      xmlFree(range->blockName);
    xmlFree(range);
}

/**
 * xmlRegCopyRange:
 * @range:  the regexp range
 *
 * Copy a regexp range
 *
 * Returns the new copy or NULL in case of error.
 */
static xmlRegRangePtr
xmlRegCopyRange(xmlRegParserCtxtPtr ctxt, xmlRegRangePtr range) {
    xmlRegRangePtr ret;

    if (range == NULL)
      return(NULL);

    ret = xmlRegNewRange(ctxt, range->neg, range->type, range->start,
                         range->end);
    if (ret == NULL)
        return(NULL);
    if (range->blockName != NULL) {
      ret->blockName = xmlStrdup(range->blockName);
      if (ret->blockName == NULL) {
          xmlRegexpErrMemory(ctxt, "allocating range");
          xmlRegFreeRange(ret);
          return(NULL);
      }
    }
    return(ret);
}

/**
 * xmlRegNewAtom:
 * @ctxt:  the regexp parser context
 * @type:  the type of atom
 *
 * Allocate a new atom
 *
 * Returns the new atom or NULL in case of error
 */
static xmlRegAtomPtr
xmlRegNewAtom(xmlRegParserCtxtPtr ctxt, xmlRegAtomType type) {
    xmlRegAtomPtr ret;

    ret = (xmlRegAtomPtr) xmlMalloc(sizeof(xmlRegAtom));
    if (ret == NULL) {
      xmlRegexpErrMemory(ctxt, "allocating atom");
      return(NULL);
    }
    memset(ret, 0, sizeof(xmlRegAtom));
    ret->type = type;
    ret->quant = XML_REGEXP_QUANT_ONCE;
    ret->min = 0;
    ret->max = 0;
    return(ret);
}

/**
 * xmlRegFreeAtom:
 * @atom:  the regexp atom
 *
 * Free a regexp atom
 */
static void
xmlRegFreeAtom(xmlRegAtomPtr atom) {
    int i;

    if (atom == NULL)
      return;

    for (i = 0;i < atom->nbRanges;i++)
      xmlRegFreeRange(atom->ranges[i]);
    if (atom->ranges != NULL)
      xmlFree(atom->ranges);
    if ((atom->type == XML_REGEXP_STRING) && (atom->valuep != NULL))
      xmlFree(atom->valuep);
    if ((atom->type == XML_REGEXP_STRING) && (atom->valuep2 != NULL))
      xmlFree(atom->valuep2);
    if ((atom->type == XML_REGEXP_BLOCK_NAME) && (atom->valuep != NULL))
      xmlFree(atom->valuep);
    xmlFree(atom);
}

/**
 * xmlRegCopyAtom:
 * @ctxt:  the regexp parser context
 * @atom:  the oiginal atom
 *
 * Allocate a new regexp range
 *
 * Returns the new atom or NULL in case of error
 */
static xmlRegAtomPtr
xmlRegCopyAtom(xmlRegParserCtxtPtr ctxt, xmlRegAtomPtr atom) {
    xmlRegAtomPtr ret;

    ret = (xmlRegAtomPtr) xmlMalloc(sizeof(xmlRegAtom));
    if (ret == NULL) {
      xmlRegexpErrMemory(ctxt, "copying atom");
      return(NULL);
    }
    memset(ret, 0, sizeof(xmlRegAtom));
    ret->type = atom->type;
    ret->quant = atom->quant;
    ret->min = atom->min;
    ret->max = atom->max;
    if (atom->nbRanges > 0) {
        int i;

        ret->ranges = (xmlRegRangePtr *) xmlMalloc(sizeof(xmlRegRangePtr) *
                                                 atom->nbRanges);
      if (ret->ranges == NULL) {
          xmlRegexpErrMemory(ctxt, "copying atom");
          goto error;
      }
      for (i = 0;i < atom->nbRanges;i++) {
          ret->ranges[i] = xmlRegCopyRange(ctxt, atom->ranges[i]);
          if (ret->ranges[i] == NULL)
              goto error;
          ret->nbRanges = i + 1;
      }
    }
    return(ret);

error:
    xmlRegFreeAtom(ret);
    return(NULL);
}

static xmlRegStatePtr
xmlRegNewState(xmlRegParserCtxtPtr ctxt) {
    xmlRegStatePtr ret;

    ret = (xmlRegStatePtr) xmlMalloc(sizeof(xmlRegState));
    if (ret == NULL) {
      xmlRegexpErrMemory(ctxt, "allocating state");
      return(NULL);
    }
    memset(ret, 0, sizeof(xmlRegState));
    ret->type = XML_REGEXP_TRANS_STATE;
    ret->mark = XML_REGEXP_MARK_NORMAL;
    return(ret);
}

/**
 * xmlRegFreeState:
 * @state:  the regexp state
 *
 * Free a regexp state
 */
static void
xmlRegFreeState(xmlRegStatePtr state) {
    if (state == NULL)
      return;

    if (state->trans != NULL)
      xmlFree(state->trans);
    if (state->transTo != NULL)
      xmlFree(state->transTo);
    xmlFree(state);
}

/**
 * xmlRegFreeParserCtxt:
 * @ctxt:  the regexp parser context
 *
 * Free a regexp parser context
 */
static void
xmlRegFreeParserCtxt(xmlRegParserCtxtPtr ctxt) {
    int i;
    if (ctxt == NULL)
      return;

    if (ctxt->string != NULL)
      xmlFree(ctxt->string);
    if (ctxt->states != NULL) {
      for (i = 0;i < ctxt->nbStates;i++)
          xmlRegFreeState(ctxt->states[i]);
      xmlFree(ctxt->states);
    }
    if (ctxt->atoms != NULL) {
      for (i = 0;i < ctxt->nbAtoms;i++)
          xmlRegFreeAtom(ctxt->atoms[i]);
      xmlFree(ctxt->atoms);
    }
    if (ctxt->counters != NULL)
      xmlFree(ctxt->counters);
    xmlFree(ctxt);
}

/************************************************************************
 *                                                    *
 *                Display of Data structures                *
 *                                                    *
 ************************************************************************/

static void
xmlRegPrintAtomType(FILE *output, xmlRegAtomType type) {
    switch (type) {
        case XML_REGEXP_EPSILON:
          fprintf(output, "epsilon "); break;
        case XML_REGEXP_CHARVAL:
          fprintf(output, "charval "); break;
        case XML_REGEXP_RANGES:
          fprintf(output, "ranges "); break;
        case XML_REGEXP_SUBREG:
          fprintf(output, "subexpr "); break;
        case XML_REGEXP_STRING:
          fprintf(output, "string "); break;
        case XML_REGEXP_ANYCHAR:
          fprintf(output, "anychar "); break;
        case XML_REGEXP_ANYSPACE:
          fprintf(output, "anyspace "); break;
        case XML_REGEXP_NOTSPACE:
          fprintf(output, "notspace "); break;
        case XML_REGEXP_INITNAME:
          fprintf(output, "initname "); break;
        case XML_REGEXP_NOTINITNAME:
          fprintf(output, "notinitname "); break;
        case XML_REGEXP_NAMECHAR:
          fprintf(output, "namechar "); break;
        case XML_REGEXP_NOTNAMECHAR:
          fprintf(output, "notnamechar "); break;
        case XML_REGEXP_DECIMAL:
          fprintf(output, "decimal "); break;
        case XML_REGEXP_NOTDECIMAL:
          fprintf(output, "notdecimal "); break;
        case XML_REGEXP_REALCHAR:
          fprintf(output, "realchar "); break;
        case XML_REGEXP_NOTREALCHAR:
          fprintf(output, "notrealchar "); break;
        case XML_REGEXP_LETTER:
            fprintf(output, "LETTER "); break;
        case XML_REGEXP_LETTER_UPPERCASE:
            fprintf(output, "LETTER_UPPERCASE "); break;
        case XML_REGEXP_LETTER_LOWERCASE:
            fprintf(output, "LETTER_LOWERCASE "); break;
        case XML_REGEXP_LETTER_TITLECASE:
            fprintf(output, "LETTER_TITLECASE "); break;
        case XML_REGEXP_LETTER_MODIFIER:
            fprintf(output, "LETTER_MODIFIER "); break;
        case XML_REGEXP_LETTER_OTHERS:
            fprintf(output, "LETTER_OTHERS "); break;
        case XML_REGEXP_MARK:
            fprintf(output, "MARK "); break;
        case XML_REGEXP_MARK_NONSPACING:
            fprintf(output, "MARK_NONSPACING "); break;
        case XML_REGEXP_MARK_SPACECOMBINING:
            fprintf(output, "MARK_SPACECOMBINING "); break;
        case XML_REGEXP_MARK_ENCLOSING:
            fprintf(output, "MARK_ENCLOSING "); break;
        case XML_REGEXP_NUMBER:
            fprintf(output, "NUMBER "); break;
        case XML_REGEXP_NUMBER_DECIMAL:
            fprintf(output, "NUMBER_DECIMAL "); break;
        case XML_REGEXP_NUMBER_LETTER:
            fprintf(output, "NUMBER_LETTER "); break;
        case XML_REGEXP_NUMBER_OTHERS:
            fprintf(output, "NUMBER_OTHERS "); break;
        case XML_REGEXP_PUNCT:
            fprintf(output, "PUNCT "); break;
        case XML_REGEXP_PUNCT_CONNECTOR:
            fprintf(output, "PUNCT_CONNECTOR "); break;
        case XML_REGEXP_PUNCT_DASH:
            fprintf(output, "PUNCT_DASH "); break;
        case XML_REGEXP_PUNCT_OPEN:
            fprintf(output, "PUNCT_OPEN "); break;
        case XML_REGEXP_PUNCT_CLOSE:
            fprintf(output, "PUNCT_CLOSE "); break;
        case XML_REGEXP_PUNCT_INITQUOTE:
            fprintf(output, "PUNCT_INITQUOTE "); break;
        case XML_REGEXP_PUNCT_FINQUOTE:
            fprintf(output, "PUNCT_FINQUOTE "); break;
        case XML_REGEXP_PUNCT_OTHERS:
            fprintf(output, "PUNCT_OTHERS "); break;
        case XML_REGEXP_SEPAR:
            fprintf(output, "SEPAR "); break;
        case XML_REGEXP_SEPAR_SPACE:
            fprintf(output, "SEPAR_SPACE "); break;
        case XML_REGEXP_SEPAR_LINE:
            fprintf(output, "SEPAR_LINE "); break;
        case XML_REGEXP_SEPAR_PARA:
            fprintf(output, "SEPAR_PARA "); break;
        case XML_REGEXP_SYMBOL:
            fprintf(output, "SYMBOL "); break;
        case XML_REGEXP_SYMBOL_MATH:
            fprintf(output, "SYMBOL_MATH "); break;
        case XML_REGEXP_SYMBOL_CURRENCY:
            fprintf(output, "SYMBOL_CURRENCY "); break;
        case XML_REGEXP_SYMBOL_MODIFIER:
            fprintf(output, "SYMBOL_MODIFIER "); break;
        case XML_REGEXP_SYMBOL_OTHERS:
            fprintf(output, "SYMBOL_OTHERS "); break;
        case XML_REGEXP_OTHER:
            fprintf(output, "OTHER "); break;
        case XML_REGEXP_OTHER_CONTROL:
            fprintf(output, "OTHER_CONTROL "); break;
        case XML_REGEXP_OTHER_FORMAT:
            fprintf(output, "OTHER_FORMAT "); break;
        case XML_REGEXP_OTHER_PRIVATE:
            fprintf(output, "OTHER_PRIVATE "); break;
        case XML_REGEXP_OTHER_NA:
            fprintf(output, "OTHER_NA "); break;
        case XML_REGEXP_BLOCK_NAME:
          fprintf(output, "BLOCK "); break;
    }
}

static void
xmlRegPrintQuantType(FILE *output, xmlRegQuantType type) {
    switch (type) {
        case XML_REGEXP_QUANT_EPSILON:
          fprintf(output, "epsilon "); break;
        case XML_REGEXP_QUANT_ONCE:
          fprintf(output, "once "); break;
        case XML_REGEXP_QUANT_OPT:
          fprintf(output, "? "); break;
        case XML_REGEXP_QUANT_MULT:
          fprintf(output, "* "); break;
        case XML_REGEXP_QUANT_PLUS:
          fprintf(output, "+ "); break;
      case XML_REGEXP_QUANT_RANGE:
          fprintf(output, "range "); break;
      case XML_REGEXP_QUANT_ONCEONLY:
          fprintf(output, "onceonly "); break;
      case XML_REGEXP_QUANT_ALL:
          fprintf(output, "all "); break;
    }
}
static void
xmlRegPrintRange(FILE *output, xmlRegRangePtr range) {
    fprintf(output, "  range: ");
    if (range->neg)
      fprintf(output, "negative ");
    xmlRegPrintAtomType(output, range->type);
    fprintf(output, "%c - %c\n", range->start, range->end);
}

static void
xmlRegPrintAtom(FILE *output, xmlRegAtomPtr atom) {
    fprintf(output, " atom: ");
    if (atom == NULL) {
      fprintf(output, "NULL\n");
      return;
    }
    if (atom->neg)
        fprintf(output, "not ");
    xmlRegPrintAtomType(output, atom->type);
    xmlRegPrintQuantType(output, atom->quant);
    if (atom->quant == XML_REGEXP_QUANT_RANGE)
      fprintf(output, "%d-%d ", atom->min, atom->max);
    if (atom->type == XML_REGEXP_STRING)
      fprintf(output, "'%s' ", (char *) atom->valuep);
    if (atom->type == XML_REGEXP_CHARVAL)
      fprintf(output, "char %c\n", atom->codepoint);
    else if (atom->type == XML_REGEXP_RANGES) {
      int i;
      fprintf(output, "%d entries\n", atom->nbRanges);
      for (i = 0; i < atom->nbRanges;i++)
          xmlRegPrintRange(output, atom->ranges[i]);
    } else if (atom->type == XML_REGEXP_SUBREG) {
      fprintf(output, "start %d end %d\n", atom->start->no, atom->stop->no);
    } else {
      fprintf(output, "\n");
    }
}

static void
xmlRegPrintTrans(FILE *output, xmlRegTransPtr trans) {
    fprintf(output, "  trans: ");
    if (trans == NULL) {
      fprintf(output, "NULL\n");
      return;
    }
    if (trans->to < 0) {
      fprintf(output, "removed\n");
      return;
    }
    if (trans->nd != 0) {
      if (trans->nd == 2)
          fprintf(output, "last not determinist, ");
      else
          fprintf(output, "not determinist, ");
    }
    if (trans->counter >= 0) {
      fprintf(output, "counted %d, ", trans->counter);
    }
    if (trans->count == REGEXP_ALL_COUNTER) {
      fprintf(output, "all transition, ");
    } else if (trans->count >= 0) {
      fprintf(output, "count based %d, ", trans->count);
    }
    if (trans->atom == NULL) {
      fprintf(output, "epsilon to %d\n", trans->to);
      return;
    }
    if (trans->atom->type == XML_REGEXP_CHARVAL)
      fprintf(output, "char %c ", trans->atom->codepoint);
    fprintf(output, "atom %d, to %d\n", trans->atom->no, trans->to);
}
    
static void
xmlRegPrintState(FILE *output, xmlRegStatePtr state) {
    int i;

    fprintf(output, " state: ");
    if (state == NULL) {
      fprintf(output, "NULL\n");
      return;
    }
    if (state->type == XML_REGEXP_START_STATE)
      fprintf(output, "START ");
    if (state->type == XML_REGEXP_FINAL_STATE)
      fprintf(output, "FINAL ");
    
    fprintf(output, "%d, %d transitions:\n", state->no, state->nbTrans);
    for (i = 0;i < state->nbTrans; i++) {
      xmlRegPrintTrans(output, &(state->trans[i]));
    }
}

#ifdef DEBUG_REGEXP_GRAPH
static void
xmlRegPrintCtxt(FILE *output, xmlRegParserCtxtPtr ctxt) {
    int i;

    fprintf(output, " ctxt: ");
    if (ctxt == NULL) {
      fprintf(output, "NULL\n");
      return;
    }
    fprintf(output, "'%s' ", ctxt->string);
    if (ctxt->error)
      fprintf(output, "error ");
    if (ctxt->neg)
      fprintf(output, "neg ");
    fprintf(output, "\n");
    fprintf(output, "%d atoms:\n", ctxt->nbAtoms);
    for (i = 0;i < ctxt->nbAtoms; i++) {
      fprintf(output, " %02d ", i);
      xmlRegPrintAtom(output, ctxt->atoms[i]);
    }
    if (ctxt->atom != NULL) {
      fprintf(output, "current atom:\n");
      xmlRegPrintAtom(output, ctxt->atom);
    }
    fprintf(output, "%d states:", ctxt->nbStates);
    if (ctxt->start != NULL)
      fprintf(output, " start: %d", ctxt->start->no);
    if (ctxt->end != NULL)
      fprintf(output, " end: %d", ctxt->end->no);
    fprintf(output, "\n");
    for (i = 0;i < ctxt->nbStates; i++) {
      xmlRegPrintState(output, ctxt->states[i]);
    }
    fprintf(output, "%d counters:\n", ctxt->nbCounters);
    for (i = 0;i < ctxt->nbCounters; i++) {
      fprintf(output, " %d: min %d max %d\n", i, ctxt->counters[i].min,
                                            ctxt->counters[i].max);
    }
}
#endif

/************************************************************************
 *                                                    *
 *           Finite Automata structures manipulations       *
 *                                                    *
 ************************************************************************/

static void 
xmlRegAtomAddRange(xmlRegParserCtxtPtr ctxt, xmlRegAtomPtr atom,
                 int neg, xmlRegAtomType type, int start, int end,
               xmlChar *blockName) {
    xmlRegRangePtr range;

    if (atom == NULL) {
      ERROR("add range: atom is NULL");
      return;
    }
    if (atom->type != XML_REGEXP_RANGES) {
      ERROR("add range: atom is not ranges");
      return;
    }
    if (atom->maxRanges == 0) {
      atom->maxRanges = 4;
      atom->ranges = (xmlRegRangePtr *) xmlMalloc(atom->maxRanges *
                                         sizeof(xmlRegRangePtr));
      if (atom->ranges == NULL) {
          xmlRegexpErrMemory(ctxt, "adding ranges");
          atom->maxRanges = 0;
          return;
      }
    } else if (atom->nbRanges >= atom->maxRanges) {
      xmlRegRangePtr *tmp;
      atom->maxRanges *= 2;
      tmp = (xmlRegRangePtr *) xmlRealloc(atom->ranges, atom->maxRanges *
                                         sizeof(xmlRegRangePtr));
      if (tmp == NULL) {
          xmlRegexpErrMemory(ctxt, "adding ranges");
          atom->maxRanges /= 2;
          return;
      }
      atom->ranges = tmp;
    }
    range = xmlRegNewRange(ctxt, neg, type, start, end);
    if (range == NULL)
      return;
    range->blockName = blockName;
    atom->ranges[atom->nbRanges++] = range;
    
}

static int
xmlRegGetCounter(xmlRegParserCtxtPtr ctxt) {
    if (ctxt->maxCounters == 0) {
      ctxt->maxCounters = 4;
      ctxt->counters = (xmlRegCounter *) xmlMalloc(ctxt->maxCounters *
                                         sizeof(xmlRegCounter));
      if (ctxt->counters == NULL) {
          xmlRegexpErrMemory(ctxt, "allocating counter");
          ctxt->maxCounters = 0;
          return(-1);
      }
    } else if (ctxt->nbCounters >= ctxt->maxCounters) {
      xmlRegCounter *tmp;
      ctxt->maxCounters *= 2;
      tmp = (xmlRegCounter *) xmlRealloc(ctxt->counters, ctxt->maxCounters *
                                       sizeof(xmlRegCounter));
      if (tmp == NULL) {
          xmlRegexpErrMemory(ctxt, "allocating counter");
          ctxt->maxCounters /= 2;
          return(-1);
      }
      ctxt->counters = tmp;
    }
    ctxt->counters[ctxt->nbCounters].min = -1;
    ctxt->counters[ctxt->nbCounters].max = -1;
    return(ctxt->nbCounters++);
}

static int 
xmlRegAtomPush(xmlRegParserCtxtPtr ctxt, xmlRegAtomPtr atom) {
    if (atom == NULL) {
      ERROR("atom push: atom is NULL");
      return(-1);
    }
    if (ctxt->maxAtoms == 0) {
      ctxt->maxAtoms = 4;
      ctxt->atoms = (xmlRegAtomPtr *) xmlMalloc(ctxt->maxAtoms *
                                         sizeof(xmlRegAtomPtr));
      if (ctxt->atoms == NULL) {
          xmlRegexpErrMemory(ctxt, "pushing atom");
          ctxt->maxAtoms = 0;
          return(-1);
      }
    } else if (ctxt->nbAtoms >= ctxt->maxAtoms) {
      xmlRegAtomPtr *tmp;
      ctxt->maxAtoms *= 2;
      tmp = (xmlRegAtomPtr *) xmlRealloc(ctxt->atoms, ctxt->maxAtoms *
                                         sizeof(xmlRegAtomPtr));
      if (tmp == NULL) {
          xmlRegexpErrMemory(ctxt, "allocating counter");
          ctxt->maxAtoms /= 2;
          return(-1);
      }
      ctxt->atoms = tmp;
    }
    atom->no = ctxt->nbAtoms;
    ctxt->atoms[ctxt->nbAtoms++] = atom;
    return(0);
}

static void 
xmlRegStateAddTransTo(xmlRegParserCtxtPtr ctxt, xmlRegStatePtr target,
                      int from) {
    if (target->maxTransTo == 0) {
      target->maxTransTo = 8;
      target->transTo = (int *) xmlMalloc(target->maxTransTo *
                                         sizeof(int));
      if (target->transTo == NULL) {
          xmlRegexpErrMemory(ctxt, "adding transition");
          target->maxTransTo = 0;
          return;
      }
    } else if (target->nbTransTo >= target->maxTransTo) {
      int *tmp;
      target->maxTransTo *= 2;
      tmp = (int *) xmlRealloc(target->transTo, target->maxTransTo *
                                         sizeof(int));
      if (tmp == NULL) {
          xmlRegexpErrMemory(ctxt, "adding transition");
          target->maxTransTo /= 2;
          return;
      }
      target->transTo = tmp;
    }
    target->transTo[target->nbTransTo] = from;
    target->nbTransTo++;
}

static void 
xmlRegStateAddTrans(xmlRegParserCtxtPtr ctxt, xmlRegStatePtr state,
                  xmlRegAtomPtr atom, xmlRegStatePtr target,
                int counter, int count) {

    int nrtrans;

    if (state == NULL) {
      ERROR("add state: state is NULL");
      return;
    }
    if (target == NULL) {
      ERROR("add state: target is NULL");
      return;
    }
    /*
     * Other routines follow the philosophy 'When in doubt, add a transition'
     * so we check here whether such a transition is already present and, if
     * so, silently ignore this request.
     */

    for (nrtrans = state->nbTrans - 1; nrtrans >= 0; nrtrans--) {
      xmlRegTransPtr trans = &(state->trans[nrtrans]);
      if ((trans->atom == atom) &&
          (trans->to == target->no) &&
          (trans->counter == counter) &&
          (trans->count == count)) {
#ifdef DEBUG_REGEXP_GRAPH
          printf("Ignoring duplicate transition from %d to %d\n",
                state->no, target->no);
#endif
          return;
      }
    }

    if (state->maxTrans == 0) {
      state->maxTrans = 8;
      state->trans = (xmlRegTrans *) xmlMalloc(state->maxTrans *
                                         sizeof(xmlRegTrans));
      if (state->trans == NULL) {
          xmlRegexpErrMemory(ctxt, "adding transition");
          state->maxTrans = 0;
          return;
      }
    } else if (state->nbTrans >= state->maxTrans) {
      xmlRegTrans *tmp;
      state->maxTrans *= 2;
      tmp = (xmlRegTrans *) xmlRealloc(state->trans, state->maxTrans *
                                         sizeof(xmlRegTrans));
      if (tmp == NULL) {
          xmlRegexpErrMemory(ctxt, "adding transition");
          state->maxTrans /= 2;
          return;
      }
      state->trans = tmp;
    }
#ifdef DEBUG_REGEXP_GRAPH
    printf("Add trans from %d to %d ", state->no, target->no);
    if (count == REGEXP_ALL_COUNTER)
      printf("all transition\n");
    else if (count >= 0)
      printf("count based %d\n", count);
    else if (counter >= 0)
      printf("counted %d\n", counter);
    else if (atom == NULL)
      printf("epsilon transition\n");
    else if (atom != NULL) 
        xmlRegPrintAtom(stdout, atom);
#endif

    state->trans[state->nbTrans].atom = atom;
    state->trans[state->nbTrans].to = target->no;
    state->trans[state->nbTrans].counter = counter;
    state->trans[state->nbTrans].count = count;
    state->trans[state->nbTrans].nd = 0;
    state->nbTrans++;
    xmlRegStateAddTransTo(ctxt, target, state->no);
}

static int
xmlRegStatePush(xmlRegParserCtxtPtr ctxt, xmlRegStatePtr state) {
    if (state == NULL) return(-1);
    if (ctxt->maxStates == 0) {
      ctxt->maxStates = 4;
      ctxt->states = (xmlRegStatePtr *) xmlMalloc(ctxt->maxStates *
                                         sizeof(xmlRegStatePtr));
      if (ctxt->states == NULL) {
          xmlRegexpErrMemory(ctxt, "adding state");
          ctxt->maxStates = 0;
          return(-1);
      }
    } else if (ctxt->nbStates >= ctxt->maxStates) {
      xmlRegStatePtr *tmp;
      ctxt->maxStates *= 2;
      tmp = (xmlRegStatePtr *) xmlRealloc(ctxt->states, ctxt->maxStates *
                                         sizeof(xmlRegStatePtr));
      if (tmp == NULL) {
          xmlRegexpErrMemory(ctxt, "adding state");
          ctxt->maxStates /= 2;
          return(-1);
      }
      ctxt->states = tmp;
    }
    state->no = ctxt->nbStates;
    ctxt->states[ctxt->nbStates++] = state;
    return(0);
}

/**
 * xmlFAGenerateAllTransition:
 * @ctxt:  a regexp parser context
 * @from:  the from state
 * @to:  the target state or NULL for building a new one
 * @lax:
 *
 */
static void
xmlFAGenerateAllTransition(xmlRegParserCtxtPtr ctxt,
                     xmlRegStatePtr from, xmlRegStatePtr to,
                     int lax) {
    if (to == NULL) {
      to = xmlRegNewState(ctxt);
      xmlRegStatePush(ctxt, to);
      ctxt->state = to;
    }
    if (lax)
      xmlRegStateAddTrans(ctxt, from, NULL, to, -1, REGEXP_ALL_LAX_COUNTER);
    else
      xmlRegStateAddTrans(ctxt, from, NULL, to, -1, REGEXP_ALL_COUNTER);
}

/**
 * xmlFAGenerateEpsilonTransition:
 * @ctxt:  a regexp parser context
 * @from:  the from state
 * @to:  the target state or NULL for building a new one
 *
 */
static void
xmlFAGenerateEpsilonTransition(xmlRegParserCtxtPtr ctxt,
                         xmlRegStatePtr from, xmlRegStatePtr to) {
    if (to == NULL) {
      to = xmlRegNewState(ctxt);
      xmlRegStatePush(ctxt, to);
      ctxt->state = to;
    }
    xmlRegStateAddTrans(ctxt, from, NULL, to, -1, -1);
}

/**
 * xmlFAGenerateCountedEpsilonTransition:
 * @ctxt:  a regexp parser context
 * @from:  the from state
 * @to:  the target state or NULL for building a new one
 * counter:  the counter for that transition
 *
 */
static void
xmlFAGenerateCountedEpsilonTransition(xmlRegParserCtxtPtr ctxt,
          xmlRegStatePtr from, xmlRegStatePtr to, int counter) {
    if (to == NULL) {
      to = xmlRegNewState(ctxt);
      xmlRegStatePush(ctxt, to);
      ctxt->state = to;
    }
    xmlRegStateAddTrans(ctxt, from, NULL, to, counter, -1);
}

/**
 * xmlFAGenerateCountedTransition:
 * @ctxt:  a regexp parser context
 * @from:  the from state
 * @to:  the target state or NULL for building a new one
 * counter:  the counter for that transition
 *
 */
static void
xmlFAGenerateCountedTransition(xmlRegParserCtxtPtr ctxt,
          xmlRegStatePtr from, xmlRegStatePtr to, int counter) {
    if (to == NULL) {
      to = xmlRegNewState(ctxt);
      xmlRegStatePush(ctxt, to);
      ctxt->state = to;
    }
    xmlRegStateAddTrans(ctxt, from, NULL, to, -1, counter);
}

/**
 * xmlFAGenerateTransitions:
 * @ctxt:  a regexp parser context
 * @from:  the from state
 * @to:  the target state or NULL for building a new one
 * @atom:  the atom generating the transition
 *
 * Returns 0 if success and -1 in case of error.
 */
static int
xmlFAGenerateTransitions(xmlRegParserCtxtPtr ctxt, xmlRegStatePtr from,
                       xmlRegStatePtr to, xmlRegAtomPtr atom) {
    xmlRegStatePtr end;

    if (atom == NULL) {
      ERROR("genrate transition: atom == NULL");
      return(-1);
    }
    if (atom->type == XML_REGEXP_SUBREG) {
      /*
       * this is a subexpression handling one should not need to
       * create a new node except for XML_REGEXP_QUANT_RANGE.
       */
      if (xmlRegAtomPush(ctxt, atom) < 0) {
          return(-1);
      }
      if ((to != NULL) && (atom->stop != to) &&
          (atom->quant != XML_REGEXP_QUANT_RANGE)) {
          /*
           * Generate an epsilon transition to link to the target
           */
          xmlFAGenerateEpsilonTransition(ctxt, atom->stop, to);
#ifdef DV
      } else if ((to == NULL) && (atom->quant != XML_REGEXP_QUANT_RANGE) && 
               (atom->quant != XML_REGEXP_QUANT_ONCE)) {
          to = xmlRegNewState(ctxt);
          xmlRegStatePush(ctxt, to);
          ctxt->state = to;
          xmlFAGenerateEpsilonTransition(ctxt, atom->stop, to);
#endif
      }
      switch (atom->quant) {
          case XML_REGEXP_QUANT_OPT:
            atom->quant = XML_REGEXP_QUANT_ONCE;
            /*
             * transition done to the state after end of atom.
             *      1. set transition from atom start to new state
             *      2. set transition from atom end to this state. 
             */
            xmlFAGenerateEpsilonTransition(ctxt, atom->start, 0);
            xmlFAGenerateEpsilonTransition(ctxt, atom->stop, ctxt->state);
            break;
          case XML_REGEXP_QUANT_MULT:
            atom->quant = XML_REGEXP_QUANT_ONCE;
            xmlFAGenerateEpsilonTransition(ctxt, atom->start, atom->stop);
            xmlFAGenerateEpsilonTransition(ctxt, atom->stop, atom->start);
            break;
          case XML_REGEXP_QUANT_PLUS:
            atom->quant = XML_REGEXP_QUANT_ONCE;
            xmlFAGenerateEpsilonTransition(ctxt, atom->stop, atom->start);
            break;
          case XML_REGEXP_QUANT_RANGE: {
            int counter;
            xmlRegStatePtr inter, newstate;

            /*
             * create the final state now if needed
             */
            if (to != NULL) {
                newstate = to;
            } else {
                newstate = xmlRegNewState(ctxt);
                xmlRegStatePush(ctxt, newstate);
            }

            /*
             * The principle here is to use counted transition
             * to avoid explosion in the number of states in the
             * graph. This is clearly more complex but should not
             * be exploitable at runtime.
             */
            if ((atom->min == 0) && (atom->start0 == NULL)) {
                xmlRegAtomPtr copy;
                /*
                 * duplicate a transition based on atom to count next
                 * occurences after 1. We cannot loop to atom->start
                 * directly because we need an epsilon transition to 
                 * newstate.
                 */
                 /* ???? For some reason it seems we never reach that
                    case, I suppose this got optimized out before when
                  building the automata */
                copy = xmlRegCopyAtom(ctxt, atom);
                if (copy == NULL)
                    return(-1);
                copy->quant = XML_REGEXP_QUANT_ONCE;
                copy->min = 0;
                copy->max = 0;

                if (xmlFAGenerateTransitions(ctxt, atom->start, NULL, copy)
                    < 0)
                  return(-1);
                inter = ctxt->state;
                counter = xmlRegGetCounter(ctxt);
                ctxt->counters[counter].min = atom->min - 1;
                ctxt->counters[counter].max = atom->max - 1;
                /* count the number of times we see it again */
                xmlFAGenerateCountedEpsilonTransition(ctxt, inter,
                                       atom->stop, counter);
                /* allow a way out based on the count */
                xmlFAGenerateCountedTransition(ctxt, inter,
                                             newstate, counter);
                /* and also allow a direct exit for 0 */
                xmlFAGenerateEpsilonTransition(ctxt, atom->start,
                                               newstate);
            } else {
                /*
                 * either we need the atom at least once or there
                 * is an atom->start0 allowing to easilly plug the
                 * epsilon transition.
                 */
                counter = xmlRegGetCounter(ctxt);
                ctxt->counters[counter].min = atom->min - 1;
                ctxt->counters[counter].max = atom->max - 1;
                /* count the number of times we see it again */
                xmlFAGenerateCountedEpsilonTransition(ctxt, atom->stop,
                                       atom->start, counter);
                /* allow a way out based on the count */
                xmlFAGenerateCountedTransition(ctxt, atom->stop,
                                             newstate, counter);
                /* and if needed allow a direct exit for 0 */
                if (atom->min == 0)
                  xmlFAGenerateEpsilonTransition(ctxt, atom->start0,
                                           newstate);

            }
            atom->min = 0;
            atom->max = 0;
            atom->quant = XML_REGEXP_QUANT_ONCE;
            ctxt->state = newstate;
          }
          default:
            break;
      }
      return(0);
    } 
    if ((atom->min == 0) && (atom->max == 0) &&
               (atom->quant == XML_REGEXP_QUANT_RANGE)) {
        /*
       * we can discard the atom and generate an epsilon transition instead
       */
      if (to == NULL) {
          to = xmlRegNewState(ctxt);
          if (to != NULL)
            xmlRegStatePush(ctxt, to);
          else {
            return(-1);
          }
      }
      xmlFAGenerateEpsilonTransition(ctxt, from, to);
      ctxt->state = to;
      xmlRegFreeAtom(atom);
      return(0);
    }
    if (to == NULL) {
      to = xmlRegNewState(ctxt);
      if (to != NULL)
          xmlRegStatePush(ctxt, to);
      else {
          return(-1);
      }
    } 
    end = to;
    if ((atom->quant == XML_REGEXP_QUANT_MULT) || 
        (atom->quant == XML_REGEXP_QUANT_PLUS)) {
      /*
       * Do not pollute the target state by adding transitions from
       * it as it is likely to be the shared target of multiple branches.
       * So isolate with an epsilon transition.
       */
        xmlRegStatePtr tmp;
      
      tmp = xmlRegNewState(ctxt);
      if (tmp != NULL)
          xmlRegStatePush(ctxt, tmp);
      else {
          return(-1);
      }
      xmlFAGenerateEpsilonTransition(ctxt, tmp, to);
      to = tmp;
    }
    if (xmlRegAtomPush(ctxt, atom) < 0) {
      return(-1);
    }
    xmlRegStateAddTrans(ctxt, from, atom, to, -1, -1);
    ctxt->state = end;
    switch (atom->quant) {
      case XML_REGEXP_QUANT_OPT:
          atom->quant = XML_REGEXP_QUANT_ONCE;
          xmlFAGenerateEpsilonTransition(ctxt, from, to);
          break;
      case XML_REGEXP_QUANT_MULT:
          atom->quant = XML_REGEXP_QUANT_ONCE;
          xmlFAGenerateEpsilonTransition(ctxt, from, to);
          xmlRegStateAddTrans(ctxt, to, atom, to, -1, -1);
          break;
      case XML_REGEXP_QUANT_PLUS:
          atom->quant = XML_REGEXP_QUANT_ONCE;
          xmlRegStateAddTrans(ctxt, to, atom, to, -1, -1);
          break;
      case XML_REGEXP_QUANT_RANGE: 
#if DV_test
          if (atom->min == 0) {
            xmlFAGenerateEpsilonTransition(ctxt, from, to);
          }
#endif
          break;
      default:
          break;
    }
    return(0);
}

/**
 * xmlFAReduceEpsilonTransitions:
 * @ctxt:  a regexp parser context
 * @fromnr:  the from state
 * @tonr:  the to state 
 * @counter:  should that transition be associated to a counted
 *
 */
static void
xmlFAReduceEpsilonTransitions(xmlRegParserCtxtPtr ctxt, int fromnr,
                            int tonr, int counter) {
    int transnr;
    xmlRegStatePtr from;
    xmlRegStatePtr to;

#ifdef DEBUG_REGEXP_GRAPH
    printf("xmlFAReduceEpsilonTransitions(%d, %d)\n", fromnr, tonr);
#endif
    from = ctxt->states[fromnr];
    if (from == NULL)
      return;
    to = ctxt->states[tonr];
    if (to == NULL)
      return;
    if ((to->mark == XML_REGEXP_MARK_START) ||
      (to->mark == XML_REGEXP_MARK_VISITED))
      return;

    to->mark = XML_REGEXP_MARK_VISITED;
    if (to->type == XML_REGEXP_FINAL_STATE) {
#ifdef DEBUG_REGEXP_GRAPH
      printf("State %d is final, so %d becomes final\n", tonr, fromnr);
#endif
      from->type = XML_REGEXP_FINAL_STATE;
    }
    for (transnr = 0;transnr < to->nbTrans;transnr++) {
        if (to->trans[transnr].to < 0)
          continue;
      if (to->trans[transnr].atom == NULL) {
          /*
           * Don't remove counted transitions
           * Don't loop either
           */
          if (to->trans[transnr].to != fromnr) {
            if (to->trans[transnr].count >= 0) {
                int newto = to->trans[transnr].to;

                xmlRegStateAddTrans(ctxt, from, NULL,
                              ctxt->states[newto], 
                              -1, to->trans[transnr].count);
            } else {
#ifdef DEBUG_REGEXP_GRAPH
                printf("Found epsilon trans %d from %d to %d\n",
                     transnr, tonr, to->trans[transnr].to);
#endif
                if (to->trans[transnr].counter >= 0) {
                  xmlFAReduceEpsilonTransitions(ctxt, fromnr,
                                    to->trans[transnr].to,
                                    to->trans[transnr].counter);
                } else {
                  xmlFAReduceEpsilonTransitions(ctxt, fromnr,
                                    to->trans[transnr].to,
                                    counter);
                }
            }
          }
      } else {
          int newto = to->trans[transnr].to;

          if (to->trans[transnr].counter >= 0) {
            xmlRegStateAddTrans(ctxt, from, to->trans[transnr].atom, 
                            ctxt->states[newto], 
                            to->trans[transnr].counter, -1);
          } else {
            xmlRegStateAddTrans(ctxt, from, to->trans[transnr].atom, 
                            ctxt->states[newto], counter, -1);
          }
      }
    }
    to->mark = XML_REGEXP_MARK_NORMAL;
}

/**
 * xmlFAEliminateSimpleEpsilonTransitions:
 * @ctxt:  a regexp parser context
 *
 * Eliminating general epsilon transitions can get costly in the general 
 * algorithm due to the large amount of generated new transitions and
 * associated comparisons. However for simple epsilon transition used just
 * to separate building blocks when generating the automata this can be
 * reduced to state elimination:
 *    - if there exists an epsilon from X to Y
 *    - if there is no other transition from X
 * then X and Y are semantically equivalent and X can be eliminated
 * If X is the start state then make Y the start state, else replace the
 * target of all transitions to X by transitions to Y.
 */
static void
xmlFAEliminateSimpleEpsilonTransitions(xmlRegParserCtxtPtr ctxt) {
    int statenr, i, j, newto;
    xmlRegStatePtr state, tmp;

    for (statenr = 0;statenr < ctxt->nbStates;statenr++) {
      state = ctxt->states[statenr];
      if (state == NULL)
          continue;
      if (state->nbTrans != 1)
          continue;
      if (state->type == XML_REGEXP_UNREACH_STATE)
          continue;
      /* is the only transition out a basic transition */
      if ((state->trans[0].atom == NULL) &&
          (state->trans[0].to >= 0) &&
          (state->trans[0].to != statenr) &&
          (state->trans[0].counter < 0) &&
          (state->trans[0].count < 0)) {
          newto = state->trans[0].to;

            if (state->type == XML_REGEXP_START_STATE) {
#ifdef DEBUG_REGEXP_GRAPH
            printf("Found simple epsilon trans from start %d to %d\n",
                   statenr, newto);
#endif     
            } else {
#ifdef DEBUG_REGEXP_GRAPH
            printf("Found simple epsilon trans from %d to %d\n",
                   statenr, newto);
#endif     
              for (i = 0;i < state->nbTransTo;i++) {
                tmp = ctxt->states[state->transTo[i]];
                for (j = 0;j < tmp->nbTrans;j++) {
                  if (tmp->trans[j].to == statenr) {
#ifdef DEBUG_REGEXP_GRAPH
                      printf("Changed transition %d on %d to go to %d\n",
                           j, tmp->no, newto);
#endif     
                      tmp->trans[j].to = -1;
                      xmlRegStateAddTrans(ctxt, tmp, tmp->trans[j].atom,
                                    ctxt->states[newto],
                                      tmp->trans[j].counter,
                                    tmp->trans[j].count);
                  }
                }
            }
            if (state->type == XML_REGEXP_FINAL_STATE)
                ctxt->states[newto]->type = XML_REGEXP_FINAL_STATE;
            /* eliminate the transition completely */
            state->nbTrans = 0;

                state->type = XML_REGEXP_UNREACH_STATE;

          }
            
      }
    }
}
/**
 * xmlFAEliminateEpsilonTransitions:
 * @ctxt:  a regexp parser context
 *
 */
static void
xmlFAEliminateEpsilonTransitions(xmlRegParserCtxtPtr ctxt) {
    int statenr, transnr;
    xmlRegStatePtr state;
    int has_epsilon;

    if (ctxt->states == NULL) return;

    /*
     * Eliminate simple epsilon transition and the associated unreachable
     * states.
     */
    xmlFAEliminateSimpleEpsilonTransitions(ctxt);
    for (statenr = 0;statenr < ctxt->nbStates;statenr++) {
      state = ctxt->states[statenr];
      if ((state != NULL) && (state->type == XML_REGEXP_UNREACH_STATE)) {
#ifdef DEBUG_REGEXP_GRAPH
          printf("Removed unreachable state %d\n", statenr);
#endif
          xmlRegFreeState(state);
          ctxt->states[statenr] = NULL;
      }
    }

    has_epsilon = 0;

    /*
     * Build the completed transitions bypassing the epsilons
     * Use a marking algorithm to avoid loops
     * Mark sink states too.
     * Process from the latests states backward to the start when
     * there is long cascading epsilon chains this minimize the
     * recursions and transition compares when adding the new ones
     */
    for (statenr = ctxt->nbStates - 1;statenr >= 0;statenr--) {
      state = ctxt->states[statenr];
      if (state == NULL)
          continue;
      if ((state->nbTrans == 0) &&
          (state->type != XML_REGEXP_FINAL_STATE)) {
          state->type = XML_REGEXP_SINK_STATE;
      }
      for (transnr = 0;transnr < state->nbTrans;transnr++) {
          if ((state->trans[transnr].atom == NULL) &&
            (state->trans[transnr].to >= 0)) {
            if (state->trans[transnr].to == statenr) {
                state->trans[transnr].to = -1;
#ifdef DEBUG_REGEXP_GRAPH
                printf("Removed loopback epsilon trans %d on %d\n",
                     transnr, statenr);
#endif
            } else if (state->trans[transnr].count < 0) {
                int newto = state->trans[transnr].to;

#ifdef DEBUG_REGEXP_GRAPH
                printf("Found epsilon trans %d from %d to %d\n",
                     transnr, statenr, newto);
#endif
                has_epsilon = 1;
                state->trans[transnr].to = -2;
                state->mark = XML_REGEXP_MARK_START;
                xmlFAReduceEpsilonTransitions(ctxt, statenr,
                              newto, state->trans[transnr].counter);
                state->mark = XML_REGEXP_MARK_NORMAL;
#ifdef DEBUG_REGEXP_GRAPH
            } else {
                printf("Found counted transition %d on %d\n",
                     transnr, statenr);
#endif
              }
          }
      }
    }
    /*
     * Eliminate the epsilon transitions
     */
    if (has_epsilon) {
      for (statenr = 0;statenr < ctxt->nbStates;statenr++) {
          state = ctxt->states[statenr];
          if (state == NULL)
            continue;
          for (transnr = 0;transnr < state->nbTrans;transnr++) {
            xmlRegTransPtr trans = &(state->trans[transnr]);
            if ((trans->atom == NULL) &&
                (trans->count < 0) &&
                (trans->to >= 0)) {
                trans->to = -1;
            }
          }
      }
    }

    /*
     * Use this pass to detect unreachable states too
     */
    for (statenr = 0;statenr < ctxt->nbStates;statenr++) {
      state = ctxt->states[statenr];
      if (state != NULL)
          state->reached = XML_REGEXP_MARK_NORMAL;
    }
    state = ctxt->states[0];
    if (state != NULL)
      state->reached = XML_REGEXP_MARK_START;
    while (state != NULL) {
      xmlRegStatePtr target = NULL;
      state->reached = XML_REGEXP_MARK_VISITED;
      /*
       * Mark all states reachable from the current reachable state
       */
      for (transnr = 0;transnr < state->nbTrans;transnr++) {
          if ((state->trans[transnr].to >= 0) &&
            ((state->trans[transnr].atom != NULL) ||
             (state->trans[transnr].count >= 0))) {
            int newto = state->trans[transnr].to;

            if (ctxt->states[newto] == NULL)
                continue;
            if (ctxt->states[newto]->reached == XML_REGEXP_MARK_NORMAL) {
                ctxt->states[newto]->reached = XML_REGEXP_MARK_START;
                target = ctxt->states[newto];
            }
          }
      }

      /*
       * find the next accessible state not explored
       */
      if (target == NULL) {
          for (statenr = 1;statenr < ctxt->nbStates;statenr++) {
            state = ctxt->states[statenr];
            if ((state != NULL) && (state->reached ==
                  XML_REGEXP_MARK_START)) {
                target = state;
                break;
            }
          }
      }
      state = target;
    }
    for (statenr = 0;statenr < ctxt->nbStates;statenr++) {
      state = ctxt->states[statenr];
      if ((state != NULL) && (state->reached == XML_REGEXP_MARK_NORMAL)) {
#ifdef DEBUG_REGEXP_GRAPH
          printf("Removed unreachable state %d\n", statenr);
#endif
          xmlRegFreeState(state);
          ctxt->states[statenr] = NULL;
      }
    }

}

static int
xmlFACompareRanges(xmlRegRangePtr range1, xmlRegRangePtr range2) {
    int ret = 0;

    if ((range1->type == XML_REGEXP_RANGES) ||
        (range2->type == XML_REGEXP_RANGES) ||
        (range2->type == XML_REGEXP_SUBREG) ||
        (range1->type == XML_REGEXP_SUBREG) ||
        (range1->type == XML_REGEXP_STRING) ||
        (range2->type == XML_REGEXP_STRING))
      return(-1);

    /* put them in order */
    if (range1->type > range2->type) {
        xmlRegRangePtr tmp;

      tmp = range1;
      range1 = range2;
      range2 = tmp;
    }
    if ((range1->type == XML_REGEXP_ANYCHAR) ||
        (range2->type == XML_REGEXP_ANYCHAR)) {
      ret = 1;
    } else if ((range1->type == XML_REGEXP_EPSILON) ||
               (range2->type == XML_REGEXP_EPSILON)) {
      return(0);
    } else if (range1->type == range2->type) {
        if ((range1->type != XML_REGEXP_CHARVAL) ||
          (range1->end < range2->start) ||
          (range2->end < range1->start))
          ret = 1;
      else
          ret = 0;
    } else if (range1->type == XML_REGEXP_CHARVAL) {
        int codepoint;
      int neg = 0;

      /*
       * just check all codepoints in the range for acceptance,
       * this is usually way cheaper since done only once at
       * compilation than testing over and over at runtime or 
       * pushing too many states when evaluating.
       */
      if (((range1->neg == 0) && (range2->neg != 0)) ||
          ((range1->neg != 0) && (range2->neg == 0)))
          neg = 1;

      for (codepoint = range1->start;codepoint <= range1->end ;codepoint++) {
          ret = xmlRegCheckCharacterRange(range2->type, codepoint,
                                  0, range2->start, range2->end,
                                  range2->blockName);
          if (ret < 0)
              return(-1);
          if (((neg == 1) && (ret == 0)) ||
              ((neg == 0) && (ret == 1)))
            return(1);
      }
      return(0);
    } else if ((range1->type == XML_REGEXP_BLOCK_NAME) ||
               (range2->type == XML_REGEXP_BLOCK_NAME)) {
      if (range1->type == range2->type) {
          ret = xmlStrEqual(range1->blockName, range2->blockName);
      } else {
          /*
           * comparing a block range with anything else is way
           * too costly, and maintining the table is like too much
           * memory too, so let's force the automata to save state
           * here.
           */
          return(1);
      }
    } else if ((range1->type < XML_REGEXP_LETTER) ||
               (range2->type < XML_REGEXP_LETTER)) {
      if ((range1->type == XML_REGEXP_ANYSPACE) &&
          (range2->type == XML_REGEXP_NOTSPACE))
          ret = 0;
      else if ((range1->type == XML_REGEXP_INITNAME) &&
               (range2->type == XML_REGEXP_NOTINITNAME))
          ret = 0;
      else if ((range1->type == XML_REGEXP_NAMECHAR) &&
               (range2->type == XML_REGEXP_NOTNAMECHAR))
          ret = 0;
      else if ((range1->type == XML_REGEXP_DECIMAL) &&
               (range2->type == XML_REGEXP_NOTDECIMAL))
          ret = 0;
      else if ((range1->type == XML_REGEXP_REALCHAR) &&
               (range2->type == XML_REGEXP_NOTREALCHAR))
          ret = 0;
      else {
          /* same thing to limit complexity */
          return(1);
      }
    } else {
        ret = 0;
        /* range1->type < range2->type here */
        switch (range1->type) {
          case XML_REGEXP_LETTER:
               /* all disjoint except in the subgroups */
               if ((range2->type == XML_REGEXP_LETTER_UPPERCASE) ||
                 (range2->type == XML_REGEXP_LETTER_LOWERCASE) ||
                 (range2->type == XML_REGEXP_LETTER_TITLECASE) ||
                 (range2->type == XML_REGEXP_LETTER_MODIFIER) ||
                 (range2->type == XML_REGEXP_LETTER_OTHERS))
                 ret = 1;
             break;
          case XML_REGEXP_MARK:
               if ((range2->type == XML_REGEXP_MARK_NONSPACING) ||
                 (range2->type == XML_REGEXP_MARK_SPACECOMBINING) ||
                 (range2->type == XML_REGEXP_MARK_ENCLOSING))
                 ret = 1;
             break;
          case XML_REGEXP_NUMBER:
               if ((range2->type == XML_REGEXP_NUMBER_DECIMAL) ||
                 (range2->type == XML_REGEXP_NUMBER_LETTER) ||
                 (range2->type == XML_REGEXP_NUMBER_OTHERS))
                 ret = 1;
             break;
          case XML_REGEXP_PUNCT:
               if ((range2->type == XML_REGEXP_PUNCT_CONNECTOR) ||
                 (range2->type == XML_REGEXP_PUNCT_DASH) ||
                 (range2->type == XML_REGEXP_PUNCT_OPEN) ||
                 (range2->type == XML_REGEXP_PUNCT_CLOSE) ||
                 (range2->type == XML_REGEXP_PUNCT_INITQUOTE) ||
                 (range2->type == XML_REGEXP_PUNCT_FINQUOTE) ||
                 (range2->type == XML_REGEXP_PUNCT_OTHERS))
                 ret = 1;
             break;
          case XML_REGEXP_SEPAR:
               if ((range2->type == XML_REGEXP_SEPAR_SPACE) ||
                 (range2->type == XML_REGEXP_SEPAR_LINE) ||
                 (range2->type == XML_REGEXP_SEPAR_PARA))
                 ret = 1;
             break;
          case XML_REGEXP_SYMBOL:
               if ((range2->type == XML_REGEXP_SYMBOL_MATH) ||
                 (range2->type == XML_REGEXP_SYMBOL_CURRENCY) ||
                 (range2->type == XML_REGEXP_SYMBOL_MODIFIER) ||
                 (range2->type == XML_REGEXP_SYMBOL_OTHERS))
                 ret = 1;
             break;
          case XML_REGEXP_OTHER:
               if ((range2->type == XML_REGEXP_OTHER_CONTROL) ||
                 (range2->type == XML_REGEXP_OTHER_FORMAT) ||
                 (range2->type == XML_REGEXP_OTHER_PRIVATE))
                 ret = 1;
             break;
            default:
               if ((range2->type >= XML_REGEXP_LETTER) &&
                 (range2->type < XML_REGEXP_BLOCK_NAME))
                 ret = 0;
             else {
                 /* safety net ! */
                 return(1);
             }
      }
    }
    if (((range1->neg == 0) && (range2->neg != 0)) ||
        ((range1->neg != 0) && (range2->neg == 0)))
      ret = !ret;
    return(1);
}

/**
 * xmlFACompareAtomTypes:
 * @type1:  an atom type
 * @type2:  an atom type
 *
 * Compares two atoms type to check whether they intersect in some ways,
 * this is used by xmlFACompareAtoms only
 *
 * Returns 1 if they may intersect and 0 otherwise
 */
static int
xmlFACompareAtomTypes(xmlRegAtomType type1, xmlRegAtomType type2) {
    if ((type1 == XML_REGEXP_EPSILON) ||
        (type1 == XML_REGEXP_CHARVAL) ||
      (type1 == XML_REGEXP_RANGES) ||
      (type1 == XML_REGEXP_SUBREG) ||
      (type1 == XML_REGEXP_STRING) ||
      (type1 == XML_REGEXP_ANYCHAR))
      return(1);
    if ((type2 == XML_REGEXP_EPSILON) ||
        (type2 == XML_REGEXP_CHARVAL) ||
      (type2 == XML_REGEXP_RANGES) ||
      (type2 == XML_REGEXP_SUBREG) ||
      (type2 == XML_REGEXP_STRING) ||
      (type2 == XML_REGEXP_ANYCHAR))
      return(1);

    if (type1 == type2) return(1);

    /* simplify subsequent compares by making sure type1 < type2 */
    if (type1 > type2) {
        xmlRegAtomType tmp = type1;
      type1 = type2;
      type2 = tmp;
    }
    switch (type1) {
        case XML_REGEXP_ANYSPACE: /* \s */
          /* can't be a letter, number, mark, pontuation, symbol */
          if ((type2 == XML_REGEXP_NOTSPACE) ||
            ((type2 >= XML_REGEXP_LETTER) &&
             (type2 <= XML_REGEXP_LETTER_OTHERS)) ||
              ((type2 >= XML_REGEXP_NUMBER) &&
             (type2 <= XML_REGEXP_NUMBER_OTHERS)) ||
              ((type2 >= XML_REGEXP_MARK) &&
             (type2 <= XML_REGEXP_MARK_ENCLOSING)) ||
              ((type2 >= XML_REGEXP_PUNCT) &&
             (type2 <= XML_REGEXP_PUNCT_OTHERS)) ||
              ((type2 >= XML_REGEXP_SYMBOL) &&
             (type2 <= XML_REGEXP_SYMBOL_OTHERS))
              ) return(0);
          break;
        case XML_REGEXP_NOTSPACE: /* \S */
          break;
        case XML_REGEXP_INITNAME: /* \l */
          /* can't be a number, mark, separator, pontuation, symbol or other */
          if ((type2 == XML_REGEXP_NOTINITNAME) ||
              ((type2 >= XML_REGEXP_NUMBER) &&
             (type2 <= XML_REGEXP_NUMBER_OTHERS)) ||
              ((type2 >= XML_REGEXP_MARK) &&
             (type2 <= XML_REGEXP_MARK_ENCLOSING)) ||
              ((type2 >= XML_REGEXP_SEPAR) &&
             (type2 <= XML_REGEXP_SEPAR_PARA)) ||
              ((type2 >= XML_REGEXP_PUNCT) &&
             (type2 <= XML_REGEXP_PUNCT_OTHERS)) ||
              ((type2 >= XML_REGEXP_SYMBOL) &&
             (type2 <= XML_REGEXP_SYMBOL_OTHERS)) ||
              ((type2 >= XML_REGEXP_OTHER) &&
             (type2 <= XML_REGEXP_OTHER_NA))
            ) return(0);
          break;
        case XML_REGEXP_NOTINITNAME: /* \L */
          break;
        case XML_REGEXP_NAMECHAR: /* \c */
          /* can't be a mark, separator, pontuation, symbol or other */
          if ((type2 == XML_REGEXP_NOTNAMECHAR) ||
              ((type2 >= XML_REGEXP_MARK) &&
             (type2 <= XML_REGEXP_MARK_ENCLOSING)) ||
              ((type2 >= XML_REGEXP_PUNCT) &&
             (type2 <= XML_REGEXP_PUNCT_OTHERS)) ||
              ((type2 >= XML_REGEXP_SEPAR) &&
             (type2 <= XML_REGEXP_SEPAR_PARA)) ||
              ((type2 >= XML_REGEXP_SYMBOL) &&
             (type2 <= XML_REGEXP_SYMBOL_OTHERS)) ||
              ((type2 >= XML_REGEXP_OTHER) &&
             (type2 <= XML_REGEXP_OTHER_NA))
            ) return(0);
          break;
        case XML_REGEXP_NOTNAMECHAR: /* \C */
          break;
        case XML_REGEXP_DECIMAL: /* \d */
          /* can't be a letter, mark, separator, pontuation, symbol or other */
          if ((type2 == XML_REGEXP_NOTDECIMAL) ||
              (type2 == XML_REGEXP_REALCHAR) ||
            ((type2 >= XML_REGEXP_LETTER) &&
             (type2 <= XML_REGEXP_LETTER_OTHERS)) ||
              ((type2 >= XML_REGEXP_MARK) &&
             (type2 <= XML_REGEXP_MARK_ENCLOSING)) ||
              ((type2 >= XML_REGEXP_PUNCT) &&
             (type2 <= XML_REGEXP_PUNCT_OTHERS)) ||
              ((type2 >= XML_REGEXP_SEPAR) &&
             (type2 <= XML_REGEXP_SEPAR_PARA)) ||
              ((type2 >= XML_REGEXP_SYMBOL) &&
             (type2 <= XML_REGEXP_SYMBOL_OTHERS)) ||
              ((type2 >= XML_REGEXP_OTHER) &&
             (type2 <= XML_REGEXP_OTHER_NA))
            )return(0);
          break;
        case XML_REGEXP_NOTDECIMAL: /* \D */
          break;
        case XML_REGEXP_REALCHAR: /* \w */
          /* can't be a mark, separator, pontuation, symbol or other */
          if ((type2 == XML_REGEXP_NOTDECIMAL) ||
              ((type2 >= XML_REGEXP_MARK) &&
             (type2 <= XML_REGEXP_MARK_ENCLOSING)) ||
              ((type2 >= XML_REGEXP_PUNCT) &&
             (type2 <= XML_REGEXP_PUNCT_OTHERS)) ||
              ((type2 >= XML_REGEXP_SEPAR) &&
             (type2 <= XML_REGEXP_SEPAR_PARA)) ||
              ((type2 >= XML_REGEXP_SYMBOL) &&
             (type2 <= XML_REGEXP_SYMBOL_OTHERS)) ||
              ((type2 >= XML_REGEXP_OTHER) &&
             (type2 <= XML_REGEXP_OTHER_NA))
            )return(0);
          break;
        case XML_REGEXP_NOTREALCHAR: /* \W */
          break;
      /*
       * at that point we know both type 1 and type2 are from
       * character categories are ordered and are different,
       * it becomes simple because this is a partition
       */
        case XML_REGEXP_LETTER:
          if (type2 <= XML_REGEXP_LETTER_OTHERS)
              return(1);
          return(0);
        case XML_REGEXP_LETTER_UPPERCASE:
        case XML_REGEXP_LETTER_LOWERCASE:
        case XML_REGEXP_LETTER_TITLECASE:
        case XML_REGEXP_LETTER_MODIFIER:
        case XML_REGEXP_LETTER_OTHERS:
          return(0);
        case XML_REGEXP_MARK:
          if (type2 <= XML_REGEXP_MARK_ENCLOSING)
              return(1);
          return(0);
        case XML_REGEXP_MARK_NONSPACING:
        case XML_REGEXP_MARK_SPACECOMBINING:
        case XML_REGEXP_MARK_ENCLOSING:
          return(0);
        case XML_REGEXP_NUMBER:
          if (type2 <= XML_REGEXP_NUMBER_OTHERS)
              return(1);
          return(0);
        case XML_REGEXP_NUMBER_DECIMAL:
        case XML_REGEXP_NUMBER_LETTER:
        case XML_REGEXP_NUMBER_OTHERS:
          return(0);
        case XML_REGEXP_PUNCT:
          if (type2 <= XML_REGEXP_PUNCT_OTHERS)
              return(1);
          return(0);
        case XML_REGEXP_PUNCT_CONNECTOR:
        case XML_REGEXP_PUNCT_DASH:
        case XML_REGEXP_PUNCT_OPEN:
        case XML_REGEXP_PUNCT_CLOSE:
        case XML_REGEXP_PUNCT_INITQUOTE:
        case XML_REGEXP_PUNCT_FINQUOTE:
        case XML_REGEXP_PUNCT_OTHERS:
          return(0);
        case XML_REGEXP_SEPAR:
          if (type2 <= XML_REGEXP_SEPAR_PARA)
              return(1);
          return(0);
        case XML_REGEXP_SEPAR_SPACE:
        case XML_REGEXP_SEPAR_LINE:
        case XML_REGEXP_SEPAR_PARA:
          return(0);
        case XML_REGEXP_SYMBOL:
          if (type2 <= XML_REGEXP_SYMBOL_OTHERS)
              return(1);
          return(0);
        case XML_REGEXP_SYMBOL_MATH:
        case XML_REGEXP_SYMBOL_CURRENCY:
        case XML_REGEXP_SYMBOL_MODIFIER:
        case XML_REGEXP_SYMBOL_OTHERS:
          return(0);
        case XML_REGEXP_OTHER:
          if (type2 <= XML_REGEXP_OTHER_NA)
              return(1);
          return(0);
        case XML_REGEXP_OTHER_CONTROL:
        case XML_REGEXP_OTHER_FORMAT:
        case XML_REGEXP_OTHER_PRIVATE:
        case XML_REGEXP_OTHER_NA:
          return(0);
      default:
          break;
    }
    return(1);
}

/**
 * xmlFAEqualAtoms:
 * @atom1:  an atom
 * @atom2:  an atom
 *
 * Compares two atoms to check whether they are the same exactly
 * this is used to remove equivalent transitions
 *
 * Returns 1 if same and 0 otherwise
 */
static int
xmlFAEqualAtoms(xmlRegAtomPtr atom1, xmlRegAtomPtr atom2) {
    int ret = 0;

    if (atom1 == atom2)
      return(1);
    if ((atom1 == NULL) || (atom2 == NULL))
      return(0);

    if (atom1->type != atom2->type)
        return(0);
    switch (atom1->type) {
        case XML_REGEXP_EPSILON:
          ret = 0;
          break;
        case XML_REGEXP_STRING:
          ret = xmlStrEqual((xmlChar *)atom1->valuep,
                            (xmlChar *)atom2->valuep);
          break;
        case XML_REGEXP_CHARVAL:
          ret = (atom1->codepoint == atom2->codepoint);
          break;
      case XML_REGEXP_RANGES:
          /* too hard to do in the general case */
          ret = 0;
      default:
          break;
    }
    return(ret);
}

/**
 * xmlFACompareAtoms:
 * @atom1:  an atom
 * @atom2:  an atom
 *
 * Compares two atoms to check whether they intersect in some ways,
 * this is used by xmlFAComputesDeterminism and xmlFARecurseDeterminism only
 *
 * Returns 1 if yes and 0 otherwise
 */
static int
xmlFACompareAtoms(xmlRegAtomPtr atom1, xmlRegAtomPtr atom2) {
    int ret = 1;

    if (atom1 == atom2)
      return(1);
    if ((atom1 == NULL) || (atom2 == NULL))
      return(0);

    if ((atom1->type == XML_REGEXP_ANYCHAR) ||
        (atom2->type == XML_REGEXP_ANYCHAR))
      return(1);

    if (atom1->type > atom2->type) {
      xmlRegAtomPtr tmp;
      tmp = atom1;
      atom1 = atom2;
      atom2 = tmp;
    }
    if (atom1->type != atom2->type) {
        ret = xmlFACompareAtomTypes(atom1->type, atom2->type);
      /* if they can't intersect at the type level break now */
      if (ret == 0)
          return(0);
    }
    switch (atom1->type) {
        case XML_REGEXP_STRING:
          ret = xmlRegStrEqualWildcard((xmlChar *)atom1->valuep,
                                       (xmlChar *)atom2->valuep);
          break;
        case XML_REGEXP_EPSILON:
          goto not_determinist;
        case XML_REGEXP_CHARVAL:
          if (atom2->type == XML_REGEXP_CHARVAL) {
            ret = (atom1->codepoint == atom2->codepoint);
          } else {
              ret = xmlRegCheckCharacter(atom2, atom1->codepoint);
            if (ret < 0)
                ret = 1;
          }
          break;
        case XML_REGEXP_RANGES:
          if (atom2->type == XML_REGEXP_RANGES) {
              int i, j, res;
            xmlRegRangePtr r1, r2;

            /*
             * need to check that none of the ranges eventually matches
             */
            for (i = 0;i < atom1->nbRanges;i++) {
                for (j = 0;j < atom2->nbRanges;j++) {
                  r1 = atom1->ranges[i];
                  r2 = atom2->ranges[j];
                  res = xmlFACompareRanges(r1, r2);
                  if (res == 1) {
                      ret = 1;
                      goto done;
                  }
                }
            }
            ret = 0;
          }
          break;
      default:
          goto not_determinist;
    }
done:
    if (atom1->neg != atom2->neg) {
        ret = !ret;
    }
    if (ret == 0)
        return(0);
not_determinist:
    return(1);
}

/**
 * xmlFARecurseDeterminism:
 * @ctxt:  a regexp parser context
 *
 * Check whether the associated regexp is determinist,
 * should be called after xmlFAEliminateEpsilonTransitions()
 *
 */
static int
xmlFARecurseDeterminism(xmlRegParserCtxtPtr ctxt, xmlRegStatePtr state,
                       int to, xmlRegAtomPtr atom) {
    int ret = 1;
    int res;
    int transnr, nbTrans;
    xmlRegTransPtr t1;

    if (state == NULL)
      return(ret);
    /*
     * don't recurse on transitions potentially added in the course of
     * the elimination.
     */
    nbTrans = state->nbTrans;
    for (transnr = 0;transnr < nbTrans;transnr++) {
      t1 = &(state->trans[transnr]);
      /*
       * check transitions conflicting with the one looked at
       */
      if (t1->atom == NULL) {
          if (t1->to < 0)
            continue;
          res = xmlFARecurseDeterminism(ctxt, ctxt->states[t1->to],
                                       to, atom);
          if (res == 0) {
              ret = 0;
            /* t1->nd = 1; */
          }
          continue;
      }
      if (t1->to != to)
          continue;
      if (xmlFACompareAtoms(t1->atom, atom)) {
          ret = 0;
          /* mark the transition as non-deterministic */
          t1->nd = 1;
      }
    }
    return(ret);
}

/**
 * xmlFAComputesDeterminism:
 * @ctxt:  a regexp parser context
 *
 * Check whether the associated regexp is determinist,
 * should be called after xmlFAEliminateEpsilonTransitions()
 *
 */
static int
xmlFAComputesDeterminism(xmlRegParserCtxtPtr ctxt) {
    int statenr, transnr;
    xmlRegStatePtr state;
    xmlRegTransPtr t1, t2, last;
    int i;
    int ret = 1;

#ifdef DEBUG_REGEXP_GRAPH
    printf("xmlFAComputesDeterminism\n");
    xmlRegPrintCtxt(stdout, ctxt);
#endif
    if (ctxt->determinist != -1)
      return(ctxt->determinist);

    /*
     * First cleanup the automata removing cancelled transitions
     */
    for (statenr = 0;statenr < ctxt->nbStates;statenr++) {
      state = ctxt->states[statenr];
      if (state == NULL)
          continue;
      if (state->nbTrans < 2)
          continue;
      for (transnr = 0;transnr < state->nbTrans;transnr++) {
          t1 = &(state->trans[transnr]);
          /*
           * Determinism checks in case of counted or all transitions
           * will have to be handled separately
           */
          if (t1->atom == NULL) {
            /* t1->nd = 1; */
            continue;
          }
          if (t1->to == -1) /* eliminated */
            continue;
          for (i = 0;i < transnr;i++) {
            t2 = &(state->trans[i]);
            if (t2->to == -1) /* eliminated */
                continue;
            if (t2->atom != NULL) {
                if (t1->to == t2->to) {
                  if (xmlFAEqualAtoms(t1->atom, t2->atom))
                      t2->to = -1; /* eliminated */
                }
            }
          }
      }
    }

    /*
     * Check for all states that there aren't 2 transitions
     * with the same atom and a different target.
     */
    for (statenr = 0;statenr < ctxt->nbStates;statenr++) {
      state = ctxt->states[statenr];
      if (state == NULL)
          continue;
      if (state->nbTrans < 2)
          continue;
      last = NULL;
      for (transnr = 0;transnr < state->nbTrans;transnr++) {
          t1 = &(state->trans[transnr]);
          /*
           * Determinism checks in case of counted or all transitions
           * will have to be handled separately
           */
          if (t1->atom == NULL) {
            continue;
          }
          if (t1->to == -1) /* eliminated */
            continue;
          for (i = 0;i < transnr;i++) {
            t2 = &(state->trans[i]);
            if (t2->to == -1) /* eliminated */
                continue;
            if (t2->atom != NULL) {
                /* not determinist ! */
                if (xmlFACompareAtoms(t1->atom, t2->atom)) {
                  ret = 0;
                  /* mark the transitions as non-deterministic ones */
                  t1->nd = 1;
                  t2->nd = 1;
                  last = t1;
                }
            } else if (t1->to != -1) {
                /*
                 * do the closure in case of remaining specific
                 * epsilon transitions like choices or all
                 */
                ret = xmlFARecurseDeterminism(ctxt, ctxt->states[t1->to],
                                       t2->to, t2->atom);
                /* don't shortcut the computation so all non deterministic
                   transition get marked down
                if (ret == 0)
                  return(0);
                 */
                if (ret == 0) {
                  t1->nd = 1;
                  /* t2->nd = 1; */
                  last = t1;
                }
            }
          }
          /* don't shortcut the computation so all non deterministic
             transition get marked down
          if (ret == 0)
            break; */
      }

      /*
       * mark specifically the last non-deterministic transition
       * from a state since there is no need to set-up rollback
       * from it
       */
      if (last != NULL) {
          last->nd = 2;
      }

      /* don't shortcut the computation so all non deterministic
         transition get marked down
      if (ret == 0)
          break; */
    }

    ctxt->determinist = ret;
    return(ret);
}

/************************************************************************
 *                                                    *
 *    Routines to check input against transition atoms            *
 *                                                    *
 ************************************************************************/

static int
xmlRegCheckCharacterRange(xmlRegAtomType type, int codepoint, int neg,
                        int start, int end, const xmlChar *blockName) {
    int ret = 0;

    switch (type) {
        case XML_REGEXP_STRING:
        case XML_REGEXP_SUBREG:
        case XML_REGEXP_RANGES:
        case XML_REGEXP_EPSILON:
          return(-1);
        case XML_REGEXP_ANYCHAR:
          ret = ((codepoint != '\n') && (codepoint != '\r'));
          break;
        case XML_REGEXP_CHARVAL:
          ret = ((codepoint >= start) && (codepoint <= end));
          break;
        case XML_REGEXP_NOTSPACE:
          neg = !neg;
        case XML_REGEXP_ANYSPACE:
          ret = ((codepoint == '\n') || (codepoint == '\r') ||
               (codepoint == '\t') || (codepoint == ' '));
          break;
        case XML_REGEXP_NOTINITNAME:
          neg = !neg;
        case XML_REGEXP_INITNAME:
          ret = (IS_LETTER(codepoint) || 
               (codepoint == '_') || (codepoint == ':'));
          break;
        case XML_REGEXP_NOTNAMECHAR:
          neg = !neg;
        case XML_REGEXP_NAMECHAR:
          ret = (IS_LETTER(codepoint) || IS_DIGIT(codepoint) ||
               (codepoint == '.') || (codepoint == '-') ||
               (codepoint == '_') || (codepoint == ':') ||
               IS_COMBINING(codepoint) || IS_EXTENDER(codepoint));
          break;
        case XML_REGEXP_NOTDECIMAL:
          neg = !neg;
        case XML_REGEXP_DECIMAL:
          ret = xmlUCSIsCatNd(codepoint);
          break;
        case XML_REGEXP_REALCHAR:
          neg = !neg;
        case XML_REGEXP_NOTREALCHAR:
          ret = xmlUCSIsCatP(codepoint);
          if (ret == 0)
            ret = xmlUCSIsCatZ(codepoint);
          if (ret == 0)
            ret = xmlUCSIsCatC(codepoint);
          break;
        case XML_REGEXP_LETTER:
          ret = xmlUCSIsCatL(codepoint);
          break;
        case XML_REGEXP_LETTER_UPPERCASE:
          ret = xmlUCSIsCatLu(codepoint);
          break;
        case XML_REGEXP_LETTER_LOWERCASE:
          ret = xmlUCSIsCatLl(codepoint);
          break;
        case XML_REGEXP_LETTER_TITLECASE:
          ret = xmlUCSIsCatLt(codepoint);
          break;
        case XML_REGEXP_LETTER_MODIFIER:
          ret = xmlUCSIsCatLm(codepoint);
          break;
        case XML_REGEXP_LETTER_OTHERS:
          ret = xmlUCSIsCatLo(codepoint);
          break;
        case XML_REGEXP_MARK:
          ret = xmlUCSIsCatM(codepoint);
          break;
        case XML_REGEXP_MARK_NONSPACING:
          ret = xmlUCSIsCatMn(codepoint);
          break;
        case XML_REGEXP_MARK_SPACECOMBINING:
          ret = xmlUCSIsCatMc(codepoint);
          break;
        case XML_REGEXP_MARK_ENCLOSING:
          ret = xmlUCSIsCatMe(codepoint);
          break;
        case XML_REGEXP_NUMBER:
          ret = xmlUCSIsCatN(codepoint);
          break;
        case XML_REGEXP_NUMBER_DECIMAL:
          ret = xmlUCSIsCatNd(codepoint);
          break;
        case XML_REGEXP_NUMBER_LETTER:
          ret = xmlUCSIsCatNl(codepoint);
          break;
        case XML_REGEXP_NUMBER_OTHERS:
          ret = xmlUCSIsCatNo(codepoint);
          break;
        case XML_REGEXP_PUNCT:
          ret = xmlUCSIsCatP(codepoint);
          break;
        case XML_REGEXP_PUNCT_CONNECTOR:
          ret = xmlUCSIsCatPc(codepoint);
          break;
        case XML_REGEXP_PUNCT_DASH:
          ret = xmlUCSIsCatPd(codepoint);
          break;
        case XML_REGEXP_PUNCT_OPEN:
          ret = xmlUCSIsCatPs(codepoint);
          break;
        case XML_REGEXP_PUNCT_CLOSE:
          ret = xmlUCSIsCatPe(codepoint);
          break;
        case XML_REGEXP_PUNCT_INITQUOTE:
          ret = xmlUCSIsCatPi(codepoint);
          break;
        case XML_REGEXP_PUNCT_FINQUOTE:
          ret = xmlUCSIsCatPf(codepoint);
          break;
        case XML_REGEXP_PUNCT_OTHERS:
          ret = xmlUCSIsCatPo(codepoint);
          break;
        case XML_REGEXP_SEPAR:
          ret = xmlUCSIsCatZ(codepoint);
          break;
        case XML_REGEXP_SEPAR_SPACE:
          ret = xmlUCSIsCatZs(codepoint);
          break;
        case XML_REGEXP_SEPAR_LINE:
          ret = xmlUCSIsCatZl(codepoint);
          break;
        case XML_REGEXP_SEPAR_PARA:
          ret = xmlUCSIsCatZp(codepoint);
          break;
        case XML_REGEXP_SYMBOL:
          ret = xmlUCSIsCatS(codepoint);
          break;
        case XML_REGEXP_SYMBOL_MATH:
          ret = xmlUCSIsCatSm(codepoint);
          break;
        case XML_REGEXP_SYMBOL_CURRENCY:
          ret = xmlUCSIsCatSc(codepoint);
          break;
        case XML_REGEXP_SYMBOL_MODIFIER:
          ret = xmlUCSIsCatSk(codepoint);
          break;
        case XML_REGEXP_SYMBOL_OTHERS:
          ret = xmlUCSIsCatSo(codepoint);
          break;
        case XML_REGEXP_OTHER:
          ret = xmlUCSIsCatC(codepoint);
          break;
        case XML_REGEXP_OTHER_CONTROL:
          ret = xmlUCSIsCatCc(codepoint);
          break;
        case XML_REGEXP_OTHER_FORMAT:
          ret = xmlUCSIsCatCf(codepoint);
          break;
        case XML_REGEXP_OTHER_PRIVATE:
          ret = xmlUCSIsCatCo(codepoint);
          break;
        case XML_REGEXP_OTHER_NA:
          /* ret = xmlUCSIsCatCn(codepoint); */
          /* Seems it doesn't exist anymore in recent Unicode releases */
          ret = 0;
          break;
        case XML_REGEXP_BLOCK_NAME:
          ret = xmlUCSIsBlock(codepoint, (const char *) blockName);
          break;
    }
    if (neg)
      return(!ret);
    return(ret);
}

static int
xmlRegCheckCharacter(xmlRegAtomPtr atom, int codepoint) {
    int i, ret = 0;
    xmlRegRangePtr range;

    if ((atom == NULL) || (!IS_CHAR(codepoint)))
      return(-1);

    switch (atom->type) {
        case XML_REGEXP_SUBREG:
        case XML_REGEXP_EPSILON:
          return(-1);
        case XML_REGEXP_CHARVAL:
            return(codepoint == atom->codepoint);
        case XML_REGEXP_RANGES: {
          int accept = 0;

          for (i = 0;i < atom->nbRanges;i++) {
            range = atom->ranges[i];
            if (range->neg == 2) {
                ret = xmlRegCheckCharacterRange(range->type, codepoint,
                                    0, range->start, range->end,
                                    range->blockName);
                if (ret != 0)
                  return(0); /* excluded char */
            } else if (range->neg) {
                ret = xmlRegCheckCharacterRange(range->type, codepoint,
                                    0, range->start, range->end,
                                    range->blockName);
                if (ret == 0)
                    accept = 1;
                else
                    return(0);
            } else {
                ret = xmlRegCheckCharacterRange(range->type, codepoint,
                                    0, range->start, range->end,
                                    range->blockName);
                if (ret != 0)
                  accept = 1; /* might still be excluded */
            }
          }
          return(accept);
      }
        case XML_REGEXP_STRING:
          printf("TODO: XML_REGEXP_STRING\n");
          return(-1);
        case XML_REGEXP_ANYCHAR:
        case XML_REGEXP_ANYSPACE:
        case XML_REGEXP_NOTSPACE:
        case XML_REGEXP_INITNAME:
        case XML_REGEXP_NOTINITNAME:
        case XML_REGEXP_NAMECHAR:
        case XML_REGEXP_NOTNAMECHAR:
        case XML_REGEXP_DECIMAL:
        case XML_REGEXP_NOTDECIMAL:
        case XML_REGEXP_REALCHAR:
        case XML_REGEXP_NOTREALCHAR:
        case XML_REGEXP_LETTER:
        case XML_REGEXP_LETTER_UPPERCASE:
        case XML_REGEXP_LETTER_LOWERCASE:
        case XML_REGEXP_LETTER_TITLECASE:
        case XML_REGEXP_LETTER_MODIFIER:
        case XML_REGEXP_LETTER_OTHERS:
        case XML_REGEXP_MARK:
        case XML_REGEXP_MARK_NONSPACING:
        case XML_REGEXP_MARK_SPACECOMBINING:
        case XML_REGEXP_MARK_ENCLOSING:
        case XML_REGEXP_NUMBER:
        case XML_REGEXP_NUMBER_DECIMAL:
        case XML_REGEXP_NUMBER_LETTER:
        case XML_REGEXP_NUMBER_OTHERS:
        case XML_REGEXP_PUNCT:
        case XML_REGEXP_PUNCT_CONNECTOR:
        case XML_REGEXP_PUNCT_DASH:
        case XML_REGEXP_PUNCT_OPEN:
        case XML_REGEXP_PUNCT_CLOSE:
        case XML_REGEXP_PUNCT_INITQUOTE:
        case XML_REGEXP_PUNCT_FINQUOTE:
        case XML_REGEXP_PUNCT_OTHERS:
        case XML_REGEXP_SEPAR:
        case XML_REGEXP_SEPAR_SPACE:
        case XML_REGEXP_SEPAR_LINE:
        case XML_REGEXP_SEPAR_PARA:
        case XML_REGEXP_SYMBOL:
        case XML_REGEXP_SYMBOL_MATH:
        case XML_REGEXP_SYMBOL_CURRENCY:
        case XML_REGEXP_SYMBOL_MODIFIER:
        case XML_REGEXP_SYMBOL_OTHERS:
        case XML_REGEXP_OTHER:
        case XML_REGEXP_OTHER_CONTROL:
        case XML_REGEXP_OTHER_FORMAT:
        case XML_REGEXP_OTHER_PRIVATE:
        case XML_REGEXP_OTHER_NA:
      case XML_REGEXP_BLOCK_NAME:
          ret = xmlRegCheckCharacterRange(atom->type, codepoint, 0, 0, 0,
                                        (const xmlChar *)atom->valuep);
          if (atom->neg)
            ret = !ret;
          break;
    }
    return(ret);
}

/************************************************************************
 *                                                    *
 *    Saving and restoring state of an execution context          *
 *                                                    *
 ************************************************************************/

#ifdef DEBUG_REGEXP_EXEC
static void
xmlFARegDebugExec(xmlRegExecCtxtPtr exec) {
    printf("state: %d:%d:idx %d", exec->state->no, exec->transno, exec->index);
    if (exec->inputStack != NULL) {
      int i;
      printf(": ");
      for (i = 0;(i < 3) && (i < exec->inputStackNr);i++)
          printf("%s ", (const char *)
                 exec->inputStack[exec->inputStackNr - (i + 1)].value);
    } else {
      printf(": %s", &(exec->inputString[exec->index]));
    }
    printf("\n");
}
#endif

static void
xmlFARegExecSave(xmlRegExecCtxtPtr exec) {
#ifdef DEBUG_REGEXP_EXEC
    printf("saving ");
    exec->transno++;
    xmlFARegDebugExec(exec);
    exec->transno--;
#endif
#ifdef MAX_PUSH
    if (exec->nbPush > MAX_PUSH) {
        return;
    }
    exec->nbPush++;
#endif

    if (exec->maxRollbacks == 0) {
      exec->maxRollbacks = 4;
      exec->rollbacks = (xmlRegExecRollback *) xmlMalloc(exec->maxRollbacks *
                                         sizeof(xmlRegExecRollback));
      if (exec->rollbacks == NULL) {
          xmlRegexpErrMemory(NULL, "saving regexp");
          exec->maxRollbacks = 0;
          return;
      }
      memset(exec->rollbacks, 0,
             exec->maxRollbacks * sizeof(xmlRegExecRollback));
    } else if (exec->nbRollbacks >= exec->maxRollbacks) {
      xmlRegExecRollback *tmp;
      int len = exec->maxRollbacks;

      exec->maxRollbacks *= 2;
      tmp = (xmlRegExecRollback *) xmlRealloc(exec->rollbacks,
                  exec->maxRollbacks * sizeof(xmlRegExecRollback));
      if (tmp == NULL) {
          xmlRegexpErrMemory(NULL, "saving regexp");
          exec->maxRollbacks /= 2;
          return;
      }
      exec->rollbacks = tmp;
      tmp = &exec->rollbacks[len];
      memset(tmp, 0, (exec->maxRollbacks - len) * sizeof(xmlRegExecRollback));
    }
    exec->rollbacks[exec->nbRollbacks].state = exec->state;
    exec->rollbacks[exec->nbRollbacks].index = exec->index;
    exec->rollbacks[exec->nbRollbacks].nextbranch = exec->transno + 1;
    if (exec->comp->nbCounters > 0) {
      if (exec->rollbacks[exec->nbRollbacks].counts == NULL) {
          exec->rollbacks[exec->nbRollbacks].counts = (int *)
            xmlMalloc(exec->comp->nbCounters * sizeof(int));
          if (exec->rollbacks[exec->nbRollbacks].counts == NULL) {
            xmlRegexpErrMemory(NULL, "saving regexp");
            exec->status = -5;
            return;
          }
      }
      memcpy(exec->rollbacks[exec->nbRollbacks].counts, exec->counts,
             exec->comp->nbCounters * sizeof(int));
    }
    exec->nbRollbacks++;
}

static void
xmlFARegExecRollBack(xmlRegExecCtxtPtr exec) {
    if (exec->nbRollbacks <= 0) {
      exec->status = -1;
#ifdef DEBUG_REGEXP_EXEC
      printf("rollback failed on empty stack\n");
#endif
      return;
    }
    exec->nbRollbacks--;
    exec->state = exec->rollbacks[exec->nbRollbacks].state;
    exec->index = exec->rollbacks[exec->nbRollbacks].index;
    exec->transno = exec->rollbacks[exec->nbRollbacks].nextbranch;
    if (exec->comp->nbCounters > 0) {
      if (exec->rollbacks[exec->nbRollbacks].counts == NULL) {
          fprintf(stderr, "exec save: allocation failed");
          exec->status = -6;
          return;
      }
      memcpy(exec->counts, exec->rollbacks[exec->nbRollbacks].counts,
             exec->comp->nbCounters * sizeof(int));
    }

#ifdef DEBUG_REGEXP_EXEC
    printf("restored ");
    xmlFARegDebugExec(exec);
#endif
}

/************************************************************************
 *                                                    *
 *    Verifier, running an input against a compiled regexp        *
 *                                                    *
 ************************************************************************/

static int
xmlFARegExec(xmlRegexpPtr comp, const xmlChar *content) {
    xmlRegExecCtxt execval;
    xmlRegExecCtxtPtr exec = &execval;
    int ret, codepoint = 0, len, deter;

    exec->inputString = content;
    exec->index = 0;
    exec->nbPush = 0;
    exec->determinist = 1;
    exec->maxRollbacks = 0;
    exec->nbRollbacks = 0;
    exec->rollbacks = NULL;
    exec->status = 0;
    exec->comp = comp;
    exec->state = comp->states[0];
    exec->transno = 0;
    exec->transcount = 0;
    exec->inputStack = NULL;
    exec->inputStackMax = 0;
    if (comp->nbCounters > 0) {
      exec->counts = (int *) xmlMalloc(comp->nbCounters * sizeof(int));
      if (exec->counts == NULL) {
          xmlRegexpErrMemory(NULL, "running regexp");
          return(-1);
      }
        memset(exec->counts, 0, comp->nbCounters * sizeof(int));
    } else
      exec->counts = NULL;
    while ((exec->status == 0) &&
         ((exec->inputString[exec->index] != 0) ||
          (exec->state->type != XML_REGEXP_FINAL_STATE))) {
      xmlRegTransPtr trans;
      xmlRegAtomPtr atom;

      /*
       * If end of input on non-terminal state, rollback, however we may
       * still have epsilon like transition for counted transitions
       * on counters, in that case don't break too early.  Additionally,
       * if we are working on a range like "AB{0,2}", where B is not present,
       * we don't want to break.
       */
      len = 1;
      if ((exec->inputString[exec->index] == 0) && (exec->counts == NULL)) {
          /*
           * if there is a transition, we must check if
           *  atom allows minOccurs of 0
           */
          if (exec->transno < exec->state->nbTrans) {
              trans = &exec->state->trans[exec->transno];
            if (trans->to >=0) {
                atom = trans->atom;
                if (!((atom->min == 0) && (atom->max > 0)))
                    goto rollback;
            }
          } else
              goto rollback;
      }

      exec->transcount = 0;
      for (;exec->transno < exec->state->nbTrans;exec->transno++) {
          trans = &exec->state->trans[exec->transno];
          if (trans->to < 0)
            continue;
          atom = trans->atom;
          ret = 0;
          deter = 1;
          if (trans->count >= 0) {
            int count;
            xmlRegCounterPtr counter;

            if (exec->counts == NULL) {
                exec->status = -1;
                goto error;
            }
            /*
             * A counted transition.
             */

            count = exec->counts[trans->count];
            counter = &exec->comp->counters[trans->count];
#ifdef DEBUG_REGEXP_EXEC
            printf("testing count %d: val %d, min %d, max %d\n",
                   trans->count, count, counter->min,  counter->max);
#endif
            ret = ((count >= counter->min) && (count <= counter->max));
            if ((ret) && (counter->min != counter->max))
                deter = 0;
          } else if (atom == NULL) {
            fprintf(stderr, "epsilon transition left at runtime\n");
            exec->status = -2;
            break;
          } else if (exec->inputString[exec->index] != 0) {
                codepoint = CUR_SCHAR(&(exec->inputString[exec->index]), len);
            ret = xmlRegCheckCharacter(atom, codepoint);
            if ((ret == 1) && (atom->min >= 0) && (atom->max > 0)) {
                xmlRegStatePtr to = comp->states[trans->to];

                /*
                 * this is a multiple input sequence
                 * If there is a counter associated increment it now.
                 * before potentially saving and rollback
                 * do not increment if the counter is already over the
                 * maximum limit in which case get to next transition
                 */
                if (trans->counter >= 0) {
                  xmlRegCounterPtr counter;

                  if ((exec->counts == NULL) ||
                      (exec->comp == NULL) ||
                      (exec->comp->counters == NULL)) {
                      exec->status = -1;
                      goto error;
                  }
                  counter = &exec->comp->counters[trans->counter];
                  if (exec->counts[trans->counter] >= counter->max)
                      continue; /* for loop on transitions */

#ifdef DEBUG_REGEXP_EXEC
                  printf("Increasing count %d\n", trans->counter);
#endif
                  exec->counts[trans->counter]++;
                }
                if (exec->state->nbTrans > exec->transno + 1) {
                  xmlFARegExecSave(exec);
                }
                exec->transcount = 1;
                do {
                  /*
                   * Try to progress as much as possible on the input
                   */
                  if (exec->transcount == atom->max) {
                      break;
                  }
                  exec->index += len;
                  /*
                   * End of input: stop here
                   */
                  if (exec->inputString[exec->index] == 0) {
                      exec->index -= len;
                      break;
                  }
                  if (exec->transcount >= atom->min) {
                      int transno = exec->transno;
                      xmlRegStatePtr state = exec->state;

                      /*
                       * The transition is acceptable save it
                       */
                      exec->transno = -1; /* trick */
                      exec->state = to;
                      xmlFARegExecSave(exec);
                      exec->transno = transno;
                      exec->state = state;
                  }
                  codepoint = CUR_SCHAR(&(exec->inputString[exec->index]),
                                      len);
                  ret = xmlRegCheckCharacter(atom, codepoint);
                  exec->transcount++;
                } while (ret == 1);
                if (exec->transcount < atom->min)
                  ret = 0;

                /*
                 * If the last check failed but one transition was found
                 * possible, rollback
                 */
                if (ret < 0)
                  ret = 0;
                if (ret == 0) {
                  goto rollback;
                }
                if (trans->counter >= 0) {
                  if (exec->counts == NULL) {
                      exec->status = -1;
                      goto error;
                  }
#ifdef DEBUG_REGEXP_EXEC
                  printf("Decreasing count %d\n", trans->counter);
#endif
                  exec->counts[trans->counter]--;
                }
            } else if ((ret == 0) && (atom->min == 0) && (atom->max > 0)) {
                /*
                 * we don't match on the codepoint, but minOccurs of 0
                 * says that's ok.  Setting len to 0 inhibits stepping
                 * over the codepoint.
                 */
                exec->transcount = 1;
                len = 0;
                ret = 1;
            }
          } else if ((atom->min == 0) && (atom->max > 0)) {
              /* another spot to match when minOccurs is 0 */
            exec->transcount = 1;
            len = 0;
            ret = 1;
          }
          if (ret == 1) {
            if ((trans->nd == 1) ||
                ((trans->count >= 0) && (deter == 0) &&
                 (exec->state->nbTrans > exec->transno + 1))) {
#ifdef DEBUG_REGEXP_EXEC
                if (trans->nd == 1)
                    printf("Saving on nd transition atom %d for %c at %d\n",
                         trans->atom->no, codepoint, exec->index);
                else
                    printf("Saving on counted transition count %d for %c at %d\n",
                         trans->count, codepoint, exec->index);
#endif
                xmlFARegExecSave(exec);
            }
            if (trans->counter >= 0) {
                xmlRegCounterPtr counter;

                    /* make sure we don't go over the counter maximum value */
                if ((exec->counts == NULL) ||
                  (exec->comp == NULL) ||
                  (exec->comp->counters == NULL)) {
                  exec->status = -1;
                  goto error;
                }
                counter = &exec->comp->counters[trans->counter];
                if (exec->counts[trans->counter] >= counter->max)
                  continue; /* for loop on transitions */
#ifdef DEBUG_REGEXP_EXEC
                printf("Increasing count %d\n", trans->counter);
#endif
                exec->counts[trans->counter]++;
            }
            if ((trans->count >= 0) &&
                (trans->count < REGEXP_ALL_COUNTER)) {
                if (exec->counts == NULL) {
                    exec->status = -1;
                  goto error;
                }
#ifdef DEBUG_REGEXP_EXEC
                printf("resetting count %d on transition\n",
                       trans->count);
#endif
                exec->counts[trans->count] = 0;
            }
#ifdef DEBUG_REGEXP_EXEC
            printf("entering state %d\n", trans->to);
#endif
            exec->state = comp->states[trans->to];
            exec->transno = 0;
            if (trans->atom != NULL) {
                exec->index += len;
            }
            goto progress;
          } else if (ret < 0) {
            exec->status = -4;
            break;
          }
      }
      if ((exec->transno != 0) || (exec->state->nbTrans == 0)) {
rollback:
          /*
           * Failed to find a way out
           */
          exec->determinist = 0;
#ifdef DEBUG_REGEXP_EXEC
          printf("rollback from state %d on %d:%c\n", exec->state->no,
                 codepoint,codepoint);
#endif
          xmlFARegExecRollBack(exec);
      }
progress:
      continue;
    }
error:
    if (exec->rollbacks != NULL) {
      if (exec->counts != NULL) {
          int i;

          for (i = 0;i < exec->maxRollbacks;i++)
            if (exec->rollbacks[i].counts != NULL)
                xmlFree(exec->rollbacks[i].counts);
      }
      xmlFree(exec->rollbacks);
    }
    if (exec->counts != NULL)
      xmlFree(exec->counts);
    if (exec->status == 0)
      return(1);
    if (exec->status == -1) {
      if (exec->nbPush > MAX_PUSH)
          return(-1);
      return(0);
    }
    return(exec->status);
}

/************************************************************************
 *                                                    *
 *    Progressive interface to the verifier one atom at a time    *
 *                                                    *
 ************************************************************************/
#ifdef DEBUG_ERR
static void testerr(xmlRegExecCtxtPtr exec);
#endif

/**
 * xmlRegNewExecCtxt:
 * @comp: a precompiled regular expression
 * @callback: a callback function used for handling progresses in the
 *            automata matching phase
 * @data: the context data associated to the callback in this context
 *
 * Build a context used for progressive evaluation of a regexp.
 *
 * Returns the new context
 */
xmlRegExecCtxtPtr
xmlRegNewExecCtxt(xmlRegexpPtr comp, xmlRegExecCallbacks callback, void *data) {
    xmlRegExecCtxtPtr exec;

    if (comp == NULL)
      return(NULL);
    if ((comp->compact == NULL) && (comp->states == NULL))
        return(NULL);
    exec = (xmlRegExecCtxtPtr) xmlMalloc(sizeof(xmlRegExecCtxt));
    if (exec == NULL) {
      xmlRegexpErrMemory(NULL, "creating execution context");
      return(NULL);
    }
    memset(exec, 0, sizeof(xmlRegExecCtxt));
    exec->inputString = NULL;
    exec->index = 0;
    exec->determinist = 1;
    exec->maxRollbacks = 0;
    exec->nbRollbacks = 0;
    exec->rollbacks = NULL;
    exec->status = 0;
    exec->comp = comp;
    if (comp->compact == NULL)
      exec->state = comp->states[0];
    exec->transno = 0;
    exec->transcount = 0;
    exec->callback = callback;
    exec->data = data;
    if (comp->nbCounters > 0) {
        /*
       * For error handling, exec->counts is allocated twice the size
       * the second half is used to store the data in case of rollback
       */
      exec->counts = (int *) xmlMalloc(comp->nbCounters * sizeof(int)
                                       * 2);
      if (exec->counts == NULL) {
          xmlRegexpErrMemory(NULL, "creating execution context");
          xmlFree(exec);
          return(NULL);
      }
        memset(exec->counts, 0, comp->nbCounters * sizeof(int) * 2);
      exec->errCounts = &exec->counts[comp->nbCounters];
    } else {
      exec->counts = NULL;
      exec->errCounts = NULL;
    }
    exec->inputStackMax = 0;
    exec->inputStackNr = 0;
    exec->inputStack = NULL;
    exec->errStateNo = -1;
    exec->errString = NULL;
    exec->nbPush = 0;
    return(exec);
}

/**
 * xmlRegFreeExecCtxt:
 * @exec: a regular expression evaulation context
 *
 * Free the structures associated to a regular expression evaulation context.
 */
void
xmlRegFreeExecCtxt(xmlRegExecCtxtPtr exec) {
    if (exec == NULL)
      return;

    if (exec->rollbacks != NULL) {
      if (exec->counts != NULL) {
          int i;

          for (i = 0;i < exec->maxRollbacks;i++)
            if (exec->rollbacks[i].counts != NULL)
                xmlFree(exec->rollbacks[i].counts);
      }
      xmlFree(exec->rollbacks);
    }
    if (exec->counts != NULL)
      xmlFree(exec->counts);
    if (exec->inputStack != NULL) {
      int i;

      for (i = 0;i < exec->inputStackNr;i++) {
          if (exec->inputStack[i].value != NULL)
            xmlFree(exec->inputStack[i].value);
      }
      xmlFree(exec->inputStack);
    }
    if (exec->errString != NULL)
        xmlFree(exec->errString);
    xmlFree(exec);
}

static void
xmlFARegExecSaveInputString(xmlRegExecCtxtPtr exec, const xmlChar *value,
                          void *data) {
#ifdef DEBUG_PUSH
    printf("saving value: %d:%s\n", exec->inputStackNr, value);
#endif
    if (exec->inputStackMax == 0) {
      exec->inputStackMax = 4;
      exec->inputStack = (xmlRegInputTokenPtr) 
          xmlMalloc(exec->inputStackMax * sizeof(xmlRegInputToken));
      if (exec->inputStack == NULL) {
          xmlRegexpErrMemory(NULL, "pushing input string");
          exec->inputStackMax = 0;
          return;
      }
    } else if (exec->inputStackNr + 1 >= exec->inputStackMax) {
      xmlRegInputTokenPtr tmp;

      exec->inputStackMax *= 2;
      tmp = (xmlRegInputTokenPtr) xmlRealloc(exec->inputStack,
                  exec->inputStackMax * sizeof(xmlRegInputToken));
      if (tmp == NULL) {
          xmlRegexpErrMemory(NULL, "pushing input string");
          exec->inputStackMax /= 2;
          return;
      }
      exec->inputStack = tmp;
    }
    exec->inputStack[exec->inputStackNr].value = xmlStrdup(value);
    exec->inputStack[exec->inputStackNr].data = data;
    exec->inputStackNr++;
    exec->inputStack[exec->inputStackNr].value = NULL;
    exec->inputStack[exec->inputStackNr].data = NULL;
}

/**
 * xmlRegStrEqualWildcard:
 * @expStr:  the string to be evaluated 
 * @valStr:  the validation string
 *
 * Checks if both strings are equal or have the same content. "*"
 * can be used as a wildcard in @valStr; "|" is used as a seperator of 
 * substrings in both @expStr and @valStr.
 *
 * Returns 1 if the comparison is satisfied and the number of substrings
 * is equal, 0 otherwise.
 */

static int
xmlRegStrEqualWildcard(const xmlChar *expStr, const xmlChar *valStr) {
    if (expStr == valStr) return(1);
    if (expStr == NULL) return(0);
    if (valStr == NULL) return(0);
    do {
      /*
      * Eval if we have a wildcard for the current item.
      */
        if (*expStr != *valStr) {
          /* if one of them starts with a wildcard make valStr be it */
          if (*valStr == '*') {
              const xmlChar *tmp;

            tmp = valStr;
            valStr = expStr;
            expStr = tmp;
          }
          if ((*valStr != 0) && (*expStr != 0) && (*expStr++ == '*')) {
            do {
                if (*valStr == XML_REG_STRING_SEPARATOR)
                  break;
                valStr++;
            } while (*valStr != 0);
            continue;
          } else
            return(0);
      }
      expStr++;
      valStr++;
    } while (*valStr != 0);
    if (*expStr != 0)
      return (0);
    else
      return (1);
}

/**
 * xmlRegCompactPushString:
 * @exec: a regexp execution context
 * @comp:  the precompiled exec with a compact table
 * @value: a string token input
 * @data: data associated to the token to reuse in callbacks
 *
 * Push one input token in the execution context
 *
 * Returns: 1 if the regexp reached a final state, 0 if non-final, and
 *     a negative value in case of error.
 */
static int
xmlRegCompactPushString(xmlRegExecCtxtPtr exec,
                      xmlRegexpPtr comp,
                      const xmlChar *value,
                      void *data) {
    int state = exec->index;
    int i, target;

    if ((comp == NULL) || (comp->compact == NULL) || (comp->stringMap == NULL))
      return(-1);
    
    if (value == NULL) {
      /*
       * are we at a final state ?
       */
      if (comp->compact[state * (comp->nbstrings + 1)] ==
            XML_REGEXP_FINAL_STATE)
          return(1);
      return(0);
    }

#ifdef DEBUG_PUSH
    printf("value pushed: %s\n", value);
#endif

    /*
     * Examine all outside transitions from current state
     */
    for (i = 0;i < comp->nbstrings;i++) {
      target = comp->compact[state * (comp->nbstrings + 1) + i + 1];
      if ((target > 0) && (target <= comp->nbstates)) {
          target--; /* to avoid 0 */    
          if (xmlRegStrEqualWildcard(comp->stringMap[i], value)) {
            exec->index = target;         
            if ((exec->callback != NULL) && (comp->transdata != NULL)) {
                exec->callback(exec->data, value,
                    comp->transdata[state * comp->nbstrings + i], data);
            }
#ifdef DEBUG_PUSH
            printf("entering state %d\n", target);
#endif
            if (comp->compact[target * (comp->nbstrings + 1)] ==
                XML_REGEXP_SINK_STATE)
                goto error;

            if (comp->compact[target * (comp->nbstrings + 1)] ==
                XML_REGEXP_FINAL_STATE)
                return(1);
            return(0);
          }
      }
    }
    /*
     * Failed to find an exit transition out from current state for the
     * current token
     */
#ifdef DEBUG_PUSH
    printf("failed to find a transition for %s on state %d\n", value, state);
#endif
error:
    if (exec->errString != NULL)
        xmlFree(exec->errString);
    exec->errString = xmlStrdup(value);
    exec->errStateNo = state;
    exec->status = -1;
#ifdef DEBUG_ERR
    testerr(exec);
#endif
    return(-1);
}

/**
 * xmlRegExecPushStringInternal:
 * @exec: a regexp execution context or NULL to indicate the end
 * @value: a string token input
 * @data: data associated to the token to reuse in callbacks
 * @compound: value was assembled from 2 strings
 *
 * Push one input token in the execution context
 *
 * Returns: 1 if the regexp reached a final state, 0 if non-final, and
 *     a negative value in case of error.
 */
static int
xmlRegExecPushStringInternal(xmlRegExecCtxtPtr exec, const xmlChar *value,
                           void *data, int compound) {
    xmlRegTransPtr trans;
    xmlRegAtomPtr atom;
    int ret;
    int final = 0;
    int progress = 1;

    if (exec == NULL)
      return(-1);
    if (exec->comp == NULL)
      return(-1);
    if (exec->status != 0)
      return(exec->status);

    if (exec->comp->compact != NULL)
      return(xmlRegCompactPushString(exec, exec->comp, value, data));

    if (value == NULL) {
        if (exec->state->type == XML_REGEXP_FINAL_STATE)
          return(1);
      final = 1;
    }

#ifdef DEBUG_PUSH
    printf("value pushed: %s\n", value);
#endif
    /*
     * If we have an active rollback stack push the new value there
     * and get back to where we were left
     */
    if ((value != NULL) && (exec->inputStackNr > 0)) {
      xmlFARegExecSaveInputString(exec, value, data);
      value = exec->inputStack[exec->index].value;
      data = exec->inputStack[exec->index].data;
#ifdef DEBUG_PUSH
      printf("value loaded: %s\n", value);
#endif
    }

    while ((exec->status == 0) &&
         ((value != NULL) ||
          ((final == 1) &&
           (exec->state->type != XML_REGEXP_FINAL_STATE)))) {

      /*
       * End of input on non-terminal state, rollback, however we may
       * still have epsilon like transition for counted transitions
       * on counters, in that case don't break too early.
       */
      if ((value == NULL) && (exec->counts == NULL))
          goto rollback;

      exec->transcount = 0;
      for (;exec->transno < exec->state->nbTrans;exec->transno++) {
          trans = &exec->state->trans[exec->transno];
          if (trans->to < 0)
            continue;
          atom = trans->atom;
          ret = 0;
          if (trans->count == REGEXP_ALL_LAX_COUNTER) {
            int i;
            int count;
            xmlRegTransPtr t;
            xmlRegCounterPtr counter;

            ret = 0;

#ifdef DEBUG_PUSH
            printf("testing all lax %d\n", trans->count);
#endif
            /*
             * Check all counted transitions from the current state
             */
            if ((value == NULL) && (final)) {
                ret = 1;
            } else if (value != NULL) {
                for (i = 0;i < exec->state->nbTrans;i++) {
                  t = &exec->state->trans[i];
                  if ((t->counter < 0) || (t == trans))
                      continue;
                  counter = &exec->comp->counters[t->counter];
                  count = exec->counts[t->counter];
                  if ((count < counter->max) && 
                        (t->atom != NULL) &&
                      (xmlStrEqual(value, t->atom->valuep))) {
                      ret = 0;
                      break;
                  }
                  if ((count >= counter->min) &&
                      (count < counter->max) &&
                      (t->atom != NULL) &&
                      (xmlStrEqual(value, t->atom->valuep))) {
                      ret = 1;
                      break;
                  }
                }
            }
          } else if (trans->count == REGEXP_ALL_COUNTER) {
            int i;
            int count;
            xmlRegTransPtr t;
            xmlRegCounterPtr counter;

            ret = 1;

#ifdef DEBUG_PUSH
            printf("testing all %d\n", trans->count);
#endif
            /*
             * Check all counted transitions from the current state
             */
            for (i = 0;i < exec->state->nbTrans;i++) {
                    t = &exec->state->trans[i];
                if ((t->counter < 0) || (t == trans))
                  continue;
                    counter = &exec->comp->counters[t->counter];
                count = exec->counts[t->counter];
                if ((count < counter->min) || (count > counter->max)) {
                  ret = 0;
                  break;
                }
            }
          } else if (trans->count >= 0) {
            int count;
            xmlRegCounterPtr counter;

            /*
             * A counted transition.
             */

            count = exec->counts[trans->count];
            counter = &exec->comp->counters[trans->count];
#ifdef DEBUG_PUSH
            printf("testing count %d: val %d, min %d, max %d\n",
                   trans->count, count, counter->min,  counter->max);
#endif
            ret = ((count >= counter->min) && (count <= counter->max));
          } else if (atom == NULL) {
            fprintf(stderr, "epsilon transition left at runtime\n");
            exec->status = -2;
            break;
          } else if (value != NULL) {
            ret = xmlRegStrEqualWildcard(atom->valuep, value);
            if (atom->neg) {
                ret = !ret;
                if (!compound)
                    ret = 0;
            }
            if ((ret == 1) && (trans->counter >= 0)) {
                xmlRegCounterPtr counter;
                int count;

                count = exec->counts[trans->counter];
                counter = &exec->comp->counters[trans->counter];
                if (count >= counter->max)
                  ret = 0;
            }

            if ((ret == 1) && (atom->min > 0) && (atom->max > 0)) {
                xmlRegStatePtr to = exec->comp->states[trans->to];

                /*
                 * this is a multiple input sequence
                 */
                if (exec->state->nbTrans > exec->transno + 1) {
                  if (exec->inputStackNr <= 0) {
                      xmlFARegExecSaveInputString(exec, value, data);
                  }
                  xmlFARegExecSave(exec);
                }
                exec->transcount = 1;
                do {
                  /*
                   * Try to progress as much as possible on the input
                   */
                  if (exec->transcount == atom->max) {
                      break;
                  }
                  exec->index++;
                  value = exec->inputStack[exec->index].value;
                  data = exec->inputStack[exec->index].data;
#ifdef DEBUG_PUSH
                  printf("value loaded: %s\n", value);
#endif

                  /*
                   * End of input: stop here
                   */
                  if (value == NULL) {
                      exec->index --;
                      break;
                  }
                  if (exec->transcount >= atom->min) {
                      int transno = exec->transno;
                      xmlRegStatePtr state = exec->state;

                      /*
                       * The transition is acceptable save it
                       */
                      exec->transno = -1; /* trick */
                      exec->state = to;
                      if (exec->inputStackNr <= 0) {
                        xmlFARegExecSaveInputString(exec, value, data);
                      }
                      xmlFARegExecSave(exec);
                      exec->transno = transno;
                      exec->state = state;
                  }
                  ret = xmlStrEqual(value, atom->valuep);
                  exec->transcount++;
                } while (ret == 1);
                if (exec->transcount < atom->min)
                  ret = 0;

                /*
                 * If the last check failed but one transition was found
                 * possible, rollback
                 */
                if (ret < 0)
                  ret = 0;
                if (ret == 0) {
                  goto rollback;
                }
            }
          }
          if (ret == 1) {
            if ((exec->callback != NULL) && (atom != NULL) &&
                  (data != NULL)) {
                exec->callback(exec->data, atom->valuep,
                             atom->data, data);
            }
            if (exec->state->nbTrans > exec->transno + 1) {
                if (exec->inputStackNr <= 0) {
                  xmlFARegExecSaveInputString(exec, value, data);
                }
                xmlFARegExecSave(exec);
            }
            if (trans->counter >= 0) {
#ifdef DEBUG_PUSH
                printf("Increasing count %d\n", trans->counter);
#endif
                exec->counts[trans->counter]++;
            }
            if ((trans->count >= 0) &&
                (trans->count < REGEXP_ALL_COUNTER)) {
#ifdef DEBUG_REGEXP_EXEC
                printf("resetting count %d on transition\n",
                       trans->count);
#endif
                exec->counts[trans->count] = 0;
            }
#ifdef DEBUG_PUSH
            printf("entering state %d\n", trans->to);
#endif
                if ((exec->comp->states[trans->to] != NULL) &&
                (exec->comp->states[trans->to]->type ==
                 XML_REGEXP_SINK_STATE)) {
                /*
                 * entering a sink state, save the current state as error
                 * state.
                 */
                if (exec->errString != NULL)
                  xmlFree(exec->errString);
                exec->errString = xmlStrdup(value);
                exec->errState = exec->state;
                memcpy(exec->errCounts, exec->counts,
                     exec->comp->nbCounters * sizeof(int));
            }
            exec->state = exec->comp->states[trans->to];
            exec->transno = 0;
            if (trans->atom != NULL) {
                if (exec->inputStack != NULL) {
                  exec->index++;
                  if (exec->index < exec->inputStackNr) {
                      value = exec->inputStack[exec->index].value;
                      data = exec->inputStack[exec->index].data;
#ifdef DEBUG_PUSH
                      printf("value loaded: %s\n", value);
#endif
                  } else {
                      value = NULL;
                      data = NULL;
#ifdef DEBUG_PUSH
                      printf("end of input\n");
#endif
                  }
                } else {
                  value = NULL;
                  data = NULL;
#ifdef DEBUG_PUSH
                  printf("end of input\n");
#endif
                }
            }
            goto progress;
          } else if (ret < 0) {
            exec->status = -4;
            break;
          }
      }
      if ((exec->transno != 0) || (exec->state->nbTrans == 0)) {
rollback:
            /*
           * if we didn't yet rollback on the current input
           * store the current state as the error state.
           */
          if ((progress) && (exec->state != NULL) &&
              (exec->state->type != XML_REGEXP_SINK_STATE)) {
              progress = 0;
            if (exec->errString != NULL)
                xmlFree(exec->errString);
            exec->errString = xmlStrdup(value);
            exec->errState = exec->state;
            memcpy(exec->errCounts, exec->counts,
                   exec->comp->nbCounters * sizeof(int));
          }

          /*
           * Failed to find a way out
           */
          exec->determinist = 0;
          xmlFARegExecRollBack(exec);
          if (exec->status == 0) {
            value = exec->inputStack[exec->index].value;
            data = exec->inputStack[exec->index].data;
#ifdef DEBUG_PUSH
            printf("value loaded: %s\n", value);
#endif
          }
      }
      continue;
progress:
        progress = 1;
      continue;
    }
    if (exec->status == 0) {
        return(exec->state->type == XML_REGEXP_FINAL_STATE);
    }
#ifdef DEBUG_ERR
    if (exec->status < 0) {
      testerr(exec);
    }
#endif
    return(exec->status);
}

/**
 * xmlRegExecPushString:
 * @exec: a regexp execution context or NULL to indicate the end
 * @value: a string token input
 * @data: data associated to the token to reuse in callbacks
 *
 * Push one input token in the execution context
 *
 * Returns: 1 if the regexp reached a final state, 0 if non-final, and
 *     a negative value in case of error.
 */
int
xmlRegExecPushString(xmlRegExecCtxtPtr exec, const xmlChar *value,
                   void *data) {
    return(xmlRegExecPushStringInternal(exec, value, data, 0));
}

/**
 * xmlRegExecPushString2:
 * @exec: a regexp execution context or NULL to indicate the end
 * @value: the first string token input
 * @value2: the second string token input
 * @data: data associated to the token to reuse in callbacks
 *
 * Push one input token in the execution context
 *
 * Returns: 1 if the regexp reached a final state, 0 if non-final, and
 *     a negative value in case of error.
 */
int
xmlRegExecPushString2(xmlRegExecCtxtPtr exec, const xmlChar *value,
                      const xmlChar *value2, void *data) {
    xmlChar buf[150];
    int lenn, lenp, ret;
    xmlChar *str;

    if (exec == NULL)
      return(-1);
    if (exec->comp == NULL)
      return(-1);
    if (exec->status != 0)
      return(exec->status);

    if (value2 == NULL)
        return(xmlRegExecPushString(exec, value, data));

    lenn = strlen((char *) value2);
    lenp = strlen((char *) value);

    if (150 < lenn + lenp + 2) {
      str = (xmlChar *) xmlMallocAtomic(lenn + lenp + 2);
      if (str == NULL) {
          exec->status = -1;
          return(-1);
      }
    } else {
      str = buf;
    }
    memcpy(&str[0], value, lenp);
    str[lenp] = XML_REG_STRING_SEPARATOR;
    memcpy(&str[lenp + 1], value2, lenn);
    str[lenn + lenp + 1] = 0;

    if (exec->comp->compact != NULL)
      ret = xmlRegCompactPushString(exec, exec->comp, str, data);
    else
        ret = xmlRegExecPushStringInternal(exec, str, data, 1);

    if (str != buf)
        xmlFree(str);
    return(ret);
}

/**
 * xmlRegExecGetValues:
 * @exec: a regexp execution context
 * @err: error extraction or normal one
 * @nbval: pointer to the number of accepted values IN/OUT
 * @nbneg: return number of negative transitions
 * @values: pointer to the array of acceptable values
 * @terminal: return value if this was a terminal state
 *
 * Extract informations from the regexp execution, internal routine to
 * implement xmlRegExecNextValues() and xmlRegExecErrInfo()
 *
 * Returns: 0 in case of success or -1 in case of error.
 */
static int
xmlRegExecGetValues(xmlRegExecCtxtPtr exec, int err,
                    int *nbval, int *nbneg,
                xmlChar **values, int *terminal) {
    int maxval;
    int nb = 0;

    if ((exec == NULL) || (nbval == NULL) || (nbneg == NULL) || 
        (values == NULL) || (*nbval <= 0))
        return(-1);

    maxval = *nbval;
    *nbval = 0;
    *nbneg = 0;
    if ((exec->comp != NULL) && (exec->comp->compact != NULL)) {
        xmlRegexpPtr comp;
      int target, i, state;

        comp = exec->comp;

      if (err) {
          if (exec->errStateNo == -1) return(-1);
          state = exec->errStateNo;
      } else {
          state = exec->index;
      }
      if (terminal != NULL) {
          if (comp->compact[state * (comp->nbstrings + 1)] ==
              XML_REGEXP_FINAL_STATE)
            *terminal = 1;
          else
            *terminal = 0;
      }
      for (i = 0;(i < comp->nbstrings) && (nb < maxval);i++) {
          target = comp->compact[state * (comp->nbstrings + 1) + i + 1];
          if ((target > 0) && (target <= comp->nbstates) &&
              (comp->compact[(target - 1) * (comp->nbstrings + 1)] !=
             XML_REGEXP_SINK_STATE)) {
              values[nb++] = comp->stringMap[i];
            (*nbval)++;
          }
      }
      for (i = 0;(i < comp->nbstrings) && (nb < maxval);i++) {
          target = comp->compact[state * (comp->nbstrings + 1) + i + 1];
          if ((target > 0) && (target <= comp->nbstates) &&
              (comp->compact[(target - 1) * (comp->nbstrings + 1)] ==
             XML_REGEXP_SINK_STATE)) {
              values[nb++] = comp->stringMap[i];
            (*nbneg)++;
          }
      }
    } else {
        int transno;
      xmlRegTransPtr trans;
      xmlRegAtomPtr atom;
      xmlRegStatePtr state;

      if (terminal != NULL) {
          if (exec->state->type == XML_REGEXP_FINAL_STATE)
            *terminal = 1;
          else
            *terminal = 0;
      }

      if (err) {
          if (exec->errState == NULL) return(-1);
          state = exec->errState;
      } else {
          if (exec->state == NULL) return(-1);
          state = exec->state;
      }
      for (transno = 0;
           (transno < state->nbTrans) && (nb < maxval);
           transno++) {
          trans = &state->trans[transno];
          if (trans->to < 0)
            continue;
          atom = trans->atom;
          if ((atom == NULL) || (atom->valuep == NULL))
            continue;
          if (trans->count == REGEXP_ALL_LAX_COUNTER) {
              /* this should not be reached but ... */
              TODO;
          } else if (trans->count == REGEXP_ALL_COUNTER) {
              /* this should not be reached but ... */
              TODO;
          } else if (trans->counter >= 0) {
            xmlRegCounterPtr counter = NULL;
            int count;

            if (err)
                count = exec->errCounts[trans->counter];
            else
                count = exec->counts[trans->counter];
            if (exec->comp != NULL)
                counter = &exec->comp->counters[trans->counter];
            if ((counter == NULL) || (count < counter->max)) {
                if (atom->neg)
                  values[nb++] = (xmlChar *) atom->valuep2;
                else
                  values[nb++] = (xmlChar *) atom->valuep;
                (*nbval)++;
            }
          } else {
                if ((exec->comp->states[trans->to] != NULL) &&
                (exec->comp->states[trans->to]->type !=
                 XML_REGEXP_SINK_STATE)) {
                if (atom->neg)
                  values[nb++] = (xmlChar *) atom->valuep2;
                else
                  values[nb++] = (xmlChar *) atom->valuep;
                (*nbval)++;
            }
          } 
      }
      for (transno = 0;
           (transno < state->nbTrans) && (nb < maxval);
           transno++) {
          trans = &state->trans[transno];
          if (trans->to < 0)
            continue;
          atom = trans->atom;
          if ((atom == NULL) || (atom->valuep == NULL))
            continue;
          if (trans->count == REGEXP_ALL_LAX_COUNTER) {
              continue;
          } else if (trans->count == REGEXP_ALL_COUNTER) {
              continue;
          } else if (trans->counter >= 0) {
              continue;
          } else {
                if ((exec->comp->states[trans->to] != NULL) &&
                (exec->comp->states[trans->to]->type ==
                 XML_REGEXP_SINK_STATE)) {
                if (atom->neg)
                  values[nb++] = (xmlChar *) atom->valuep2;
                else
                  values[nb++] = (xmlChar *) atom->valuep;
                (*nbneg)++;
            }
          } 
      }
    }
    return(0);
}

/**
 * xmlRegExecNextValues:
 * @exec: a regexp execution context
 * @nbval: pointer to the number of accepted values IN/OUT
 * @nbneg: return number of negative transitions
 * @values: pointer to the array of acceptable values
 * @terminal: return value if this was a terminal state
 *
 * Extract informations from the regexp execution,
 * the parameter @values must point to an array of @nbval string pointers
 * on return nbval will contain the number of possible strings in that
 * state and the @values array will be updated with them. The string values
 * returned will be freed with the @exec context and don't need to be
 * deallocated.
 *
 * Returns: 0 in case of success or -1 in case of error.
 */
int
xmlRegExecNextValues(xmlRegExecCtxtPtr exec, int *nbval, int *nbneg,
                     xmlChar **values, int *terminal) {
    return(xmlRegExecGetValues(exec, 0, nbval, nbneg, values, terminal));
}

/**
 * xmlRegExecErrInfo:
 * @exec: a regexp execution context generating an error
 * @string: return value for the error string
 * @nbval: pointer to the number of accepted values IN/OUT
 * @nbneg: return number of negative transitions
 * @values: pointer to the array of acceptable values
 * @terminal: return value if this was a terminal state
 *
 * Extract error informations from the regexp execution, the parameter
 * @string will be updated with the value pushed and not accepted,
 * the parameter @values must point to an array of @nbval string pointers
 * on return nbval will contain the number of possible strings in that
 * state and the @values array will be updated with them. The string values
 * returned will be freed with the @exec context and don't need to be
 * deallocated.
 *
 * Returns: 0 in case of success or -1 in case of error.
 */
int
xmlRegExecErrInfo(xmlRegExecCtxtPtr exec, const xmlChar **string,
                  int *nbval, int *nbneg, xmlChar **values, int *terminal) {
    if (exec == NULL)
        return(-1);
    if (string != NULL) {
        if (exec->status != 0)
          *string = exec->errString;
      else
          *string = NULL;
    }
    return(xmlRegExecGetValues(exec, 1, nbval, nbneg, values, terminal));
}

#ifdef DEBUG_ERR
static void testerr(xmlRegExecCtxtPtr exec) {
    const xmlChar *string;
    xmlChar *values[5];
    int nb = 5;
    int nbneg;
    int terminal;
    xmlRegExecErrInfo(exec, &string, &nb, &nbneg, &values[0], &terminal);
}
#endif

#if 0
static int
xmlRegExecPushChar(xmlRegExecCtxtPtr exec, int UCS) {
    xmlRegTransPtr trans;
    xmlRegAtomPtr atom;
    int ret;
    int codepoint, len;

    if (exec == NULL)
      return(-1);
    if (exec->status != 0)
      return(exec->status);

    while ((exec->status == 0) &&
         ((exec->inputString[exec->index] != 0) ||
          (exec->state->type != XML_REGEXP_FINAL_STATE))) {

      /*
       * End of input on non-terminal state, rollback, however we may
       * still have epsilon like transition for counted transitions
       * on counters, in that case don't break too early.
       */
      if ((exec->inputString[exec->index] == 0) && (exec->counts == NULL))
          goto rollback;

      exec->transcount = 0;
      for (;exec->transno < exec->state->nbTrans;exec->transno++) {
          trans = &exec->state->trans[exec->transno];
          if (trans->to < 0)
            continue;
          atom = trans->atom;
          ret = 0;
          if (trans->count >= 0) {
            int count;
            xmlRegCounterPtr counter;

            /*
             * A counted transition.
             */

            count = exec->counts[trans->count];
            counter = &exec->comp->counters[trans->count];
#ifdef DEBUG_REGEXP_EXEC
            printf("testing count %d: val %d, min %d, max %d\n",
                   trans->count, count, counter->min,  counter->max);
#endif
            ret = ((count >= counter->min) && (count <= counter->max));
          } else if (atom == NULL) {
            fprintf(stderr, "epsilon transition left at runtime\n");
            exec->status = -2;
            break;
          } else if (exec->inputString[exec->index] != 0) {
                codepoint = CUR_SCHAR(&(exec->inputString[exec->index]), len);
            ret = xmlRegCheckCharacter(atom, codepoint);
            if ((ret == 1) && (atom->min > 0) && (atom->max > 0)) {
                xmlRegStatePtr to = exec->comp->states[trans->to];

                /*
                 * this is a multiple input sequence
                 */
                if (exec->state->nbTrans > exec->transno + 1) {
                  xmlFARegExecSave(exec);
                }
                exec->transcount = 1;
                do {
                  /*
                   * Try to progress as much as possible on the input
                   */
                  if (exec->transcount == atom->max) {
                      break;
                  }
                  exec->index += len;
                  /*
                   * End of input: stop here
                   */
                  if (exec->inputString[exec->index] == 0) {
                      exec->index -= len;
                      break;
                  }
                  if (exec->transcount >= atom->min) {
                      int transno = exec->transno;
                      xmlRegStatePtr state = exec->state;

                      /*
                       * The transition is acceptable save it
                       */
                      exec->transno = -1; /* trick */
                      exec->state = to;
                      xmlFARegExecSave(exec);
                      exec->transno = transno;
                      exec->state = state;
                  }
                  codepoint = CUR_SCHAR(&(exec->inputString[exec->index]),
                                      len);
                  ret = xmlRegCheckCharacter(atom, codepoint);
                  exec->transcount++;
                } while (ret == 1);
                if (exec->transcount < atom->min)
                  ret = 0;

                /*
                 * If the last check failed but one transition was found
                 * possible, rollback
                 */
                if (ret < 0)
                  ret = 0;
                if (ret == 0) {
                  goto rollback;
                }
            }
          }
          if (ret == 1) {
            if (exec->state->nbTrans > exec->transno + 1) {
                xmlFARegExecSave(exec);
            }
            /*
             * restart count for expressions like this ((abc){2})*
             */
            if (trans->count >= 0) {
#ifdef DEBUG_REGEXP_EXEC
                printf("Reset count %d\n", trans->count);
#endif
                exec->counts[trans->count] = 0;
            }
            if (trans->counter >= 0) {
#ifdef DEBUG_REGEXP_EXEC
                printf("Increasing count %d\n", trans->counter);
#endif
                exec->counts[trans->counter]++;
            }
#ifdef DEBUG_REGEXP_EXEC
            printf("entering state %d\n", trans->to);
#endif
            exec->state = exec->comp->states[trans->to];
            exec->transno = 0;
            if (trans->atom != NULL) {
                exec->index += len;
            }
            goto progress;
          } else if (ret < 0) {
            exec->status = -4;
            break;
          }
      }
      if ((exec->transno != 0) || (exec->state->nbTrans == 0)) {
rollback:
          /*
           * Failed to find a way out
           */
          exec->determinist = 0;
          xmlFARegExecRollBack(exec);
      }
progress:
      continue;
    }
}
#endif
/************************************************************************
 *                                                    *
 *    Parser for the Schemas Datatype Regular Expressions         *
 *    http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#regexs  *
 *                                                    *
 ************************************************************************/

/**
 * xmlFAIsChar:
 * @ctxt:  a regexp parser context
 *
 * [10]   Char   ::=   [^.\?*+()|#x5B#x5D]
 */
static int
xmlFAIsChar(xmlRegParserCtxtPtr ctxt) {
    int cur;
    int len;

    cur = CUR_SCHAR(ctxt->cur, len);
    if ((cur == '.') || (cur == '\\') || (cur == '?') ||
      (cur == '*') || (cur == '+') || (cur == '(') ||
      (cur == ')') || (cur == '|') || (cur == 0x5B) ||
      (cur == 0x5D) || (cur == 0))
      return(-1);
    return(cur);
}

/**
 * xmlFAParseCharProp:
 * @ctxt:  a regexp parser context
 *
 * [27]   charProp   ::=   IsCategory | IsBlock
 * [28]   IsCategory ::= Letters | Marks | Numbers | Punctuation |
 *                       Separators | Symbols | Others 
 * [29]   Letters   ::=   'L' [ultmo]?
 * [30]   Marks   ::=   'M' [nce]?
 * [31]   Numbers   ::=   'N' [dlo]?
 * [32]   Punctuation   ::=   'P' [cdseifo]?
 * [33]   Separators   ::=   'Z' [slp]?
 * [34]   Symbols   ::=   'S' [mcko]?
 * [35]   Others   ::=   'C' [cfon]?
 * [36]   IsBlock   ::=   'Is' [a-zA-Z0-9#x2D]+
 */
static void
xmlFAParseCharProp(xmlRegParserCtxtPtr ctxt) {
    int cur;
    xmlRegAtomType type = (xmlRegAtomType) 0;
    xmlChar *blockName = NULL;
    
    cur = CUR;
    if (cur == 'L') {
      NEXT;
      cur = CUR;
      if (cur == 'u') {
          NEXT;
          type = XML_REGEXP_LETTER_UPPERCASE;
      } else if (cur == 'l') {
          NEXT;
          type = XML_REGEXP_LETTER_LOWERCASE;
      } else if (cur == 't') {
          NEXT;
          type = XML_REGEXP_LETTER_TITLECASE;
      } else if (cur == 'm') {
          NEXT;
          type = XML_REGEXP_LETTER_MODIFIER;
      } else if (cur == 'o') {
          NEXT;
          type = XML_REGEXP_LETTER_OTHERS;
      } else {
          type = XML_REGEXP_LETTER;
      }
    } else if (cur == 'M') {
      NEXT;
      cur = CUR;
      if (cur == 'n') {
          NEXT;
          /* nonspacing */
          type = XML_REGEXP_MARK_NONSPACING;
      } else if (cur == 'c') {
          NEXT;
          /* spacing combining */
          type = XML_REGEXP_MARK_SPACECOMBINING;
      } else if (cur == 'e') {
          NEXT;
          /* enclosing */
          type = XML_REGEXP_MARK_ENCLOSING;
      } else {
          /* all marks */
          type = XML_REGEXP_MARK;
      }
    } else if (cur == 'N') {
      NEXT;
      cur = CUR;
      if (cur == 'd') {
          NEXT;
          /* digital */
          type = XML_REGEXP_NUMBER_DECIMAL;
      } else if (cur == 'l') {
          NEXT;
          /* letter */
          type = XML_REGEXP_NUMBER_LETTER;
      } else if (cur == 'o') {
          NEXT;
          /* other */
          type = XML_REGEXP_NUMBER_OTHERS;
      } else {
          /* all numbers */
          type = XML_REGEXP_NUMBER;
      }
    } else if (cur == 'P') {
      NEXT;
      cur = CUR;
      if (cur == 'c') {
          NEXT;
          /* connector */
          type = XML_REGEXP_PUNCT_CONNECTOR;
      } else if (cur == 'd') {
          NEXT;
          /* dash */
          type = XML_REGEXP_PUNCT_DASH;
      } else if (cur == 's') {
          NEXT;
          /* open */
          type = XML_REGEXP_PUNCT_OPEN;
      } else if (cur == 'e') {
          NEXT;
          /* close */
          type = XML_REGEXP_PUNCT_CLOSE;
      } else if (cur == 'i') {
          NEXT;
          /* initial quote */
          type = XML_REGEXP_PUNCT_INITQUOTE;
      } else if (cur == 'f') {
          NEXT;
          /* final quote */
          type = XML_REGEXP_PUNCT_FINQUOTE;
      } else if (cur == 'o') {
          NEXT;
          /* other */
          type = XML_REGEXP_PUNCT_OTHERS;
      } else {
          /* all punctuation */
          type = XML_REGEXP_PUNCT;
      }
    } else if (cur == 'Z') {
      NEXT;
      cur = CUR;
      if (cur == 's') {
          NEXT;
          /* space */
          type = XML_REGEXP_SEPAR_SPACE;
      } else if (cur == 'l') {
          NEXT;
          /* line */
          type = XML_REGEXP_SEPAR_LINE;
      } else if (cur == 'p') {
          NEXT;
          /* paragraph */
          type = XML_REGEXP_SEPAR_PARA;
      } else {
          /* all separators */
          type = XML_REGEXP_SEPAR;
      }
    } else if (cur == 'S') {
      NEXT;
      cur = CUR;
      if (cur == 'm') {
          NEXT;
          type = XML_REGEXP_SYMBOL_MATH;
          /* math */
      } else if (cur == 'c') {
          NEXT;
          type = XML_REGEXP_SYMBOL_CURRENCY;
          /* currency */
      } else if (cur == 'k') {
          NEXT;
          type = XML_REGEXP_SYMBOL_MODIFIER;
          /* modifiers */
      } else if (cur == 'o') {
          NEXT;
          type = XML_REGEXP_SYMBOL_OTHERS;
          /* other */
      } else {
          /* all symbols */
          type = XML_REGEXP_SYMBOL;
      }
    } else if (cur == 'C') {
      NEXT;
      cur = CUR;
      if (cur == 'c') {
          NEXT;
          /* control */
          type = XML_REGEXP_OTHER_CONTROL;
      } else if (cur == 'f') {
          NEXT;
          /* format */
          type = XML_REGEXP_OTHER_FORMAT;
      } else if (cur == 'o') {
          NEXT;
          /* private use */
          type = XML_REGEXP_OTHER_PRIVATE;
      } else if (cur == 'n') {
          NEXT;
          /* not assigned */
          type = XML_REGEXP_OTHER_NA;
      } else {
          /* all others */
          type = XML_REGEXP_OTHER;
      }
    } else if (cur == 'I') {
      const xmlChar *start;
      NEXT;
      cur = CUR;
      if (cur != 's') {
          ERROR("IsXXXX expected");
          return;
      }
      NEXT;
      start = ctxt->cur;
      cur = CUR;
      if (((cur >= 'a') && (cur <= 'z')) || 
          ((cur >= 'A') && (cur <= 'Z')) || 
          ((cur >= '0') && (cur <= '9')) || 
          (cur == 0x2D)) {
          NEXT;
          cur = CUR;
          while (((cur >= 'a') && (cur <= 'z')) || 
            ((cur >= 'A') && (cur <= 'Z')) || 
            ((cur >= '0') && (cur <= '9')) || 
            (cur == 0x2D)) {
            NEXT;
            cur = CUR;
          }
      }
      type = XML_REGEXP_BLOCK_NAME;
      blockName = xmlStrndup(start, ctxt->cur - start);
    } else {
      ERROR("Unknown char property");
      return;
    }
    if (ctxt->atom == NULL) {
      ctxt->atom = xmlRegNewAtom(ctxt, type);
      if (ctxt->atom != NULL)
          ctxt->atom->valuep = blockName;
    } else if (ctxt->atom->type == XML_REGEXP_RANGES) {
        xmlRegAtomAddRange(ctxt, ctxt->atom, ctxt->neg,
                       type, 0, 0, blockName);
    }
}

/**
 * xmlFAParseCharClassEsc:
 * @ctxt:  a regexp parser context
 *
 * [23] charClassEsc ::= ( SingleCharEsc | MultiCharEsc | catEsc | complEsc ) 
 * [24] SingleCharEsc ::= '\' [nrt\|.?*+(){}#x2D#x5B#x5D#x5E]
 * [25] catEsc   ::=   '\p{' charProp '}'
 * [26] complEsc ::=   '\P{' charProp '}'
 * [37] MultiCharEsc ::= '.' | ('\' [sSiIcCdDwW])
 */
static void
xmlFAParseCharClassEsc(xmlRegParserCtxtPtr ctxt) {
    int cur;

    if (CUR == '.') {
      if (ctxt->atom == NULL) {
          ctxt->atom = xmlRegNewAtom(ctxt, XML_REGEXP_ANYCHAR);
      } else if (ctxt->atom->type == XML_REGEXP_RANGES) {
          xmlRegAtomAddRange(ctxt, ctxt->atom, ctxt->neg,
                         XML_REGEXP_ANYCHAR, 0, 0, NULL);
      }
      NEXT;
      return;
    }
    if (CUR != '\\') {
      ERROR("Escaped sequence: expecting \\");
      return;
    }
    NEXT;
    cur = CUR;
    if (cur == 'p') {
      NEXT;
      if (CUR != '{') {
          ERROR("Expecting '{'");
          return;
      }
      NEXT;
      xmlFAParseCharProp(ctxt);
      if (CUR != '}') {
          ERROR("Expecting '}'");
          return;
      }
      NEXT;
    } else if (cur == 'P') {
      NEXT;
      if (CUR != '{') {
          ERROR("Expecting '{'");
          return;
      }
      NEXT;
      xmlFAParseCharProp(ctxt);
      ctxt->atom->neg = 1;
      if (CUR != '}') {
          ERROR("Expecting '}'");
          return;
      }
      NEXT;
    } else if ((cur == 'n') || (cur == 'r') || (cur == 't') || (cur == '\\') ||
      (cur == '|') || (cur == '.') || (cur == '?') || (cur == '*') ||
      (cur == '+') || (cur == '(') || (cur == ')') || (cur == '{') ||
      (cur == '}') || (cur == 0x2D) || (cur == 0x5B) || (cur == 0x5D) ||
      (cur == 0x5E)) {
      if (ctxt->atom == NULL) {
          ctxt->atom = xmlRegNewAtom(ctxt, XML_REGEXP_CHARVAL);
          if (ctxt->atom != NULL) {
              switch (cur) {
                case 'n':
                    ctxt->atom->codepoint = '\n';
                  break;
                case 'r':
                    ctxt->atom->codepoint = '\r';
                  break;
                case 't':
                    ctxt->atom->codepoint = '\t';
                  break;
                default:
                  ctxt->atom->codepoint = cur;
            }
          }
      } else if (ctxt->atom->type == XML_REGEXP_RANGES) {
          xmlRegAtomAddRange(ctxt, ctxt->atom, ctxt->neg,
                         XML_REGEXP_CHARVAL, cur, cur, NULL);
      }
      NEXT;
    } else if ((cur == 's') || (cur == 'S') || (cur == 'i') || (cur == 'I') ||
      (cur == 'c') || (cur == 'C') || (cur == 'd') || (cur == 'D') ||
      (cur == 'w') || (cur == 'W')) {
      xmlRegAtomType type = XML_REGEXP_ANYSPACE;

      switch (cur) {
          case 's': 
            type = XML_REGEXP_ANYSPACE;
            break;
          case 'S': 
            type = XML_REGEXP_NOTSPACE;
            break;
          case 'i': 
            type = XML_REGEXP_INITNAME;
            break;
          case 'I': 
            type = XML_REGEXP_NOTINITNAME;
            break;
          case 'c': 
            type = XML_REGEXP_NAMECHAR;
            break;
          case 'C': 
            type = XML_REGEXP_NOTNAMECHAR;
            break;
          case 'd': 
            type = XML_REGEXP_DECIMAL;
            break;
          case 'D': 
            type = XML_REGEXP_NOTDECIMAL;
            break;
          case 'w': 
            type = XML_REGEXP_REALCHAR;
            break;
          case 'W': 
            type = XML_REGEXP_NOTREALCHAR;
            break;
      }
      NEXT;
      if (ctxt->atom == NULL) {
          ctxt->atom = xmlRegNewAtom(ctxt, type);
      } else if (ctxt->atom->type == XML_REGEXP_RANGES) {
          xmlRegAtomAddRange(ctxt, ctxt->atom, ctxt->neg,
                         type, 0, 0, NULL);
      }
    } else {
      ERROR("Wrong escape sequence, misuse of character '\\'");
    }
}

/**
 * xmlFAParseCharRef:
 * @ctxt:  a regexp parser context
 *
 * [19]   XmlCharRef   ::=   ( '&#' [0-9]+ ';' ) | (' &#x' [0-9a-fA-F]+ ';' )
 */
static int
xmlFAParseCharRef(xmlRegParserCtxtPtr ctxt) {
    int ret = 0, cur;

    if ((CUR != '&') || (NXT(1) != '#'))
      return(-1);
    NEXT;
    NEXT;
    cur = CUR;
    if (cur == 'x') {
      NEXT;
      cur = CUR;
      if (((cur >= '0') && (cur <= '9')) ||
          ((cur >= 'a') && (cur <= 'f')) ||
          ((cur >= 'A') && (cur <= 'F'))) {
          while (((cur >= '0') && (cur <= '9')) ||
                 ((cur >= 'a') && (cur <= 'f')) ||
               ((cur >= 'A') && (cur <= 'F'))) {
            if ((cur >= '0') && (cur <= '9'))
                ret = ret * 16 + cur - '0';
            else if ((cur >= 'a') && (cur <= 'f'))
                ret = ret * 16 + 10 + (cur - 'a');
            else
                ret = ret * 16 + 10 + (cur - 'A');
            NEXT;
            cur = CUR;
          }
      } else {
          ERROR("Char ref: expecting [0-9A-F]");
          return(-1);
      }
    } else {
      if ((cur >= '0') && (cur <= '9')) {
          while ((cur >= '0') && (cur <= '9')) {
            ret = ret * 10 + cur - '0';
            NEXT;
            cur = CUR;
          }
      } else {
          ERROR("Char ref: expecting [0-9]");
          return(-1);
      }
    }
    if (cur != ';') {
      ERROR("Char ref: expecting ';'");
      return(-1);
    } else {
      NEXT;
    }
    return(ret);
}

/**
 * xmlFAParseCharRange:
 * @ctxt:  a regexp parser context
 *
 * [17]   charRange   ::=     seRange | XmlCharRef | XmlCharIncDash 
 * [18]   seRange   ::=   charOrEsc '-' charOrEsc
 * [20]   charOrEsc   ::=   XmlChar | SingleCharEsc
 * [21]   XmlChar   ::=   [^\#x2D#x5B#x5D]
 * [22]   XmlCharIncDash   ::=   [^\#x5B#x5D]
 */
static void
xmlFAParseCharRange(xmlRegParserCtxtPtr ctxt) {
    int cur, len;
    int start = -1;
    int end = -1;

    if (CUR == '\0') {
        ERROR("Expecting ']'");
      return;
    }

    if ((CUR == '&') && (NXT(1) == '#')) {
      end = start = xmlFAParseCharRef(ctxt);
        xmlRegAtomAddRange(ctxt, ctxt->atom, ctxt->neg,
                         XML_REGEXP_CHARVAL, start, end, NULL);
      return;
    }
    cur = CUR;
    if (cur == '\\') {
      NEXT;
      cur = CUR;
      switch (cur) {
          case 'n': start = 0xA; break;
          case 'r': start = 0xD; break;
          case 't': start = 0x9; break;
          case '\\': case '|': case '.': case '-': case '^': case '?':
          case '*': case '+': case '{': case '}': case '(': case ')':
          case '[': case ']':
            start = cur; break;
          default:
            ERROR("Invalid escape value");
            return;
      }
      end = start;
        len = 1;
    } else if ((cur != 0x5B) && (cur != 0x5D)) {
        end = start = CUR_SCHAR(ctxt->cur, len);
    } else {
      ERROR("Expecting a char range");
      return;
    }
    /*
     * Since we are "inside" a range, we can assume ctxt->cur is past
     * the start of ctxt->string, and PREV should be safe
     */
    if ((start == '-') && (NXT(1) != ']') && (PREV != '[') && (PREV != '^')) {
      NEXTL(len);
      return;
    }
    NEXTL(len);
    cur = CUR;
    if ((cur != '-') || (NXT(1) == ']')) {
        xmlRegAtomAddRange(ctxt, ctxt->atom, ctxt->neg,
                          XML_REGEXP_CHARVAL, start, end, NULL);
      return;
    }
    NEXT;
    cur = CUR;
    if (cur == '\\') {
      NEXT;
      cur = CUR;
      switch (cur) {
          case 'n': end = 0xA; break;
          case 'r': end = 0xD; break;
          case 't': end = 0x9; break;
          case '\\': case '|': case '.': case '-': case '^': case '?':
          case '*': case '+': case '{': case '}': case '(': case ')':
          case '[': case ']':
            end = cur; break;
          default:
            ERROR("Invalid escape value");
            return;
      }
        len = 1;
    } else if ((cur != 0x5B) && (cur != 0x5D)) {
        end = CUR_SCHAR(ctxt->cur, len);
    } else {
      ERROR("Expecting the end of a char range");
      return;
    }
    NEXTL(len);
    /* TODO check that the values are acceptable character ranges for XML */
    if (end < start) {
      ERROR("End of range is before start of range");
    } else {
        xmlRegAtomAddRange(ctxt, ctxt->atom, ctxt->neg,
                       XML_REGEXP_CHARVAL, start, end, NULL);
    }
    return;
}

/**
 * xmlFAParsePosCharGroup:
 * @ctxt:  a regexp parser context
 *
 * [14]   posCharGroup ::= ( charRange | charClassEsc  )+
 */
static void
xmlFAParsePosCharGroup(xmlRegParserCtxtPtr ctxt) {
    do {
      if (CUR == '\\') {
          xmlFAParseCharClassEsc(ctxt);
      } else {
          xmlFAParseCharRange(ctxt);
      }
    } while ((CUR != ']') && (CUR != '^') && (CUR != '-') &&
             (CUR != 0) && (ctxt->error == 0));
}

/**
 * xmlFAParseCharGroup:
 * @ctxt:  a regexp parser context
 *
 * [13]   charGroup    ::= posCharGroup | negCharGroup | charClassSub
 * [15]   negCharGroup ::= '^' posCharGroup
 * [16]   charClassSub ::= ( posCharGroup | negCharGroup ) '-' charClassExpr  
 * [12]   charClassExpr ::= '[' charGroup ']'
 */
static void
xmlFAParseCharGroup(xmlRegParserCtxtPtr ctxt) {
    int n = ctxt->neg;
    while ((CUR != ']') && (ctxt->error == 0)) {
      if (CUR == '^') {
          int neg = ctxt->neg;

          NEXT;
          ctxt->neg = !ctxt->neg;
          xmlFAParsePosCharGroup(ctxt);
          ctxt->neg = neg;
      } else if ((CUR == '-') && (NXT(1) == '[')) {
          int neg = ctxt->neg;
          ctxt->neg = 2;
          NEXT;   /* eat the '-' */
          NEXT;   /* eat the '[' */
          xmlFAParseCharGroup(ctxt);
          if (CUR == ']') {
            NEXT;
          } else {
            ERROR("charClassExpr: ']' expected");
            break;
          }
          ctxt->neg = neg;
          break;
      } else if (CUR != ']') {
          xmlFAParsePosCharGroup(ctxt);
      }
    }
    ctxt->neg = n;
}

/**
 * xmlFAParseCharClass:
 * @ctxt:  a regexp parser context
 *
 * [11]   charClass   ::=     charClassEsc | charClassExpr
 * [12]   charClassExpr   ::=   '[' charGroup ']'
 */
static void
xmlFAParseCharClass(xmlRegParserCtxtPtr ctxt) {
    if (CUR == '[') {
      NEXT;
      ctxt->atom = xmlRegNewAtom(ctxt, XML_REGEXP_RANGES);
      if (ctxt->atom == NULL)
          return;
      xmlFAParseCharGroup(ctxt);
      if (CUR == ']') {
          NEXT;
      } else {
          ERROR("xmlFAParseCharClass: ']' expected");
      }
    } else {
      xmlFAParseCharClassEsc(ctxt);
    }
}

/**
 * xmlFAParseQuantExact:
 * @ctxt:  a regexp parser context
 *
 * [8]   QuantExact   ::=   [0-9]+
 *
 * Returns 0 if success or -1 in case of error
 */
static int
xmlFAParseQuantExact(xmlRegParserCtxtPtr ctxt) {
    int ret = 0;
    int ok = 0;

    while ((CUR >= '0') && (CUR <= '9')) {
      ret = ret * 10 + (CUR - '0');
      ok = 1;
      NEXT;
    }
    if (ok != 1) {
      return(-1);
    }
    return(ret);
}

/**
 * xmlFAParseQuantifier:
 * @ctxt:  a regexp parser context
 *
 * [4]   quantifier   ::=   [?*+] | ( '{' quantity '}' )
 * [5]   quantity   ::=   quantRange | quantMin | QuantExact
 * [6]   quantRange   ::=   QuantExact ',' QuantExact
 * [7]   quantMin   ::=   QuantExact ','
 * [8]   QuantExact   ::=   [0-9]+
 */
static int
xmlFAParseQuantifier(xmlRegParserCtxtPtr ctxt) {
    int cur;

    cur = CUR;
    if ((cur == '?') || (cur == '*') || (cur == '+')) {
      if (ctxt->atom != NULL) {
          if (cur == '?')
            ctxt->atom->quant = XML_REGEXP_QUANT_OPT;
          else if (cur == '*')
            ctxt->atom->quant = XML_REGEXP_QUANT_MULT;
          else if (cur == '+')
            ctxt->atom->quant = XML_REGEXP_QUANT_PLUS;
      }
      NEXT;
      return(1);
    }
    if (cur == '{') {
      int min = 0, max = 0;

      NEXT;
      cur = xmlFAParseQuantExact(ctxt);
      if (cur >= 0)
          min = cur;
      if (CUR == ',') {
          NEXT;
          if (CUR == '}')
              max = INT_MAX;
          else {
              cur = xmlFAParseQuantExact(ctxt);
              if (cur >= 0)
                max = cur;
            else {
                ERROR("Improper quantifier");
            }
          }
      }
      if (CUR == '}') {
          NEXT;
      } else {
          ERROR("Unterminated quantifier");
      }
      if (max == 0)
          max = min;
      if (ctxt->atom != NULL) {
          ctxt->atom->quant = XML_REGEXP_QUANT_RANGE;
          ctxt->atom->min = min;
          ctxt->atom->max = max;
      }
      return(1);
    }
    return(0);
}

/**
 * xmlFAParseAtom:
 * @ctxt:  a regexp parser context
 *
 * [9]   atom   ::=   Char | charClass | ( '(' regExp ')' )
 */
static int
xmlFAParseAtom(xmlRegParserCtxtPtr ctxt) {
    int codepoint, len;

    codepoint = xmlFAIsChar(ctxt);
    if (codepoint > 0) {
      ctxt->atom = xmlRegNewAtom(ctxt, XML_REGEXP_CHARVAL);
      if (ctxt->atom == NULL)
          return(-1);
      codepoint = CUR_SCHAR(ctxt->cur, len);
      ctxt->atom->codepoint = codepoint;
      NEXTL(len);
      return(1);
    } else if (CUR == '|') {
      return(0);
    } else if (CUR == 0) {
      return(0);
    } else if (CUR == ')') {
      return(0);
    } else if (CUR == '(') {
      xmlRegStatePtr start, oldend, start0;

      NEXT;
      /*
       * this extra Epsilon transition is needed if we count with 0 allowed
       * unfortunately this can't be known at that point
       */
      xmlFAGenerateEpsilonTransition(ctxt, ctxt->state, NULL);
      start0 = ctxt->state;
      xmlFAGenerateEpsilonTransition(ctxt, ctxt->state, NULL);
      start = ctxt->state;
      oldend = ctxt->end;
      ctxt->end = NULL;
      ctxt->atom = NULL;
      xmlFAParseRegExp(ctxt, 0);
      if (CUR == ')') {
          NEXT;
      } else {
          ERROR("xmlFAParseAtom: expecting ')'");
      }
      ctxt->atom = xmlRegNewAtom(ctxt, XML_REGEXP_SUBREG);
      if (ctxt->atom == NULL)
          return(-1);
      ctxt->atom->start = start;
      ctxt->atom->start0 = start0;
      ctxt->atom->stop = ctxt->state;
      ctxt->end = oldend;
      return(1);
    } else if ((CUR == '[') || (CUR == '\\') || (CUR == '.')) {
      xmlFAParseCharClass(ctxt);
      return(1);
    }
    return(0);
}

/**
 * xmlFAParsePiece:
 * @ctxt:  a regexp parser context
 *
 * [3]   piece   ::=   atom quantifier?
 */
static int
xmlFAParsePiece(xmlRegParserCtxtPtr ctxt) {
    int ret;

    ctxt->atom = NULL;
    ret = xmlFAParseAtom(ctxt);
    if (ret == 0)
      return(0);
    if (ctxt->atom == NULL) {
      ERROR("internal: no atom generated");
    }
    xmlFAParseQuantifier(ctxt);
    return(1);
}

/**
 * xmlFAParseBranch:
 * @ctxt:  a regexp parser context
 * @to: optional target to the end of the branch
 *
 * @to is used to optimize by removing duplicate path in automata
 * in expressions like (a|b)(c|d)
 *
 * [2]   branch   ::=   piece*
 */
static int
xmlFAParseBranch(xmlRegParserCtxtPtr ctxt, xmlRegStatePtr to) {
    xmlRegStatePtr previous;
    int ret;

    previous = ctxt->state;
    ret = xmlFAParsePiece(ctxt);
    if (ret != 0) {
      if (xmlFAGenerateTransitions(ctxt, previous, 
              (CUR=='|' || CUR==')') ? to : NULL, ctxt->atom) < 0)
          return(-1);
      previous = ctxt->state;
      ctxt->atom = NULL;
    }
    while ((ret != 0) && (ctxt->error == 0)) {
      ret = xmlFAParsePiece(ctxt);
      if (ret != 0) {
          if (xmlFAGenerateTransitions(ctxt, previous, 
                  (CUR=='|' || CUR==')') ? to : NULL, ctxt->atom) < 0)
                return(-1);
          previous = ctxt->state;
          ctxt->atom = NULL;
      }
    }
    return(0);
}

/**
 * xmlFAParseRegExp:
 * @ctxt:  a regexp parser context
 * @top:  is this the top-level expression ?
 *
 * [1]   regExp   ::=     branch  ( '|' branch )*
 */
static void
xmlFAParseRegExp(xmlRegParserCtxtPtr ctxt, int top) {
    xmlRegStatePtr start, end;

    /* if not top start should have been generated by an epsilon trans */
    start = ctxt->state;
    ctxt->end = NULL;
    xmlFAParseBranch(ctxt, NULL);
    if (top) {
#ifdef DEBUG_REGEXP_GRAPH
      printf("State %d is final\n", ctxt->state->no);
#endif
      ctxt->state->type = XML_REGEXP_FINAL_STATE;
    }
    if (CUR != '|') {
      ctxt->end = ctxt->state;
      return;
    }
    end = ctxt->state;
    while ((CUR == '|') && (ctxt->error == 0)) {
      NEXT;
      ctxt->state = start;
      ctxt->end = NULL;
      xmlFAParseBranch(ctxt, end);
    }
    if (!top) {
      ctxt->state = end;
      ctxt->end = end;
    }
}

/************************************************************************
 *                                                    *
 *                The basic API                             *
 *                                                    *
 ************************************************************************/

/**
 * xmlRegexpPrint:
 * @output: the file for the output debug
 * @regexp: the compiled regexp
 *
 * Print the content of the compiled regular expression
 */
void
xmlRegexpPrint(FILE *output, xmlRegexpPtr regexp) {
    int i;

    if (output == NULL)
        return;
    fprintf(output, " regexp: ");
    if (regexp == NULL) {
      fprintf(output, "NULL\n");
      return;
    }
    fprintf(output, "'%s' ", regexp->string);
    fprintf(output, "\n");
    fprintf(output, "%d atoms:\n", regexp->nbAtoms);
    for (i = 0;i < regexp->nbAtoms; i++) {
      fprintf(output, " %02d ", i);
      xmlRegPrintAtom(output, regexp->atoms[i]);
    }
    fprintf(output, "%d states:", regexp->nbStates);
    fprintf(output, "\n");
    for (i = 0;i < regexp->nbStates; i++) {
      xmlRegPrintState(output, regexp->states[i]);
    }
    fprintf(output, "%d counters:\n", regexp->nbCounters);
    for (i = 0;i < regexp->nbCounters; i++) {
      fprintf(output, " %d: min %d max %d\n", i, regexp->counters[i].min,
                                            regexp->counters[i].max);
    }
}

/**
 * xmlRegexpCompile:
 * @regexp:  a regular expression string
 *
 * Parses a regular expression conforming to XML Schemas Part 2 Datatype
 * Appendix F and builds an automata suitable for testing strings against
 * that regular expression
 *
 * Returns the compiled expression or NULL in case of error
 */
xmlRegexpPtr
xmlRegexpCompile(const xmlChar *regexp) {
    xmlRegexpPtr ret;
    xmlRegParserCtxtPtr ctxt;

    ctxt = xmlRegNewParserCtxt(regexp);
    if (ctxt == NULL)
      return(NULL);

    /* initialize the parser */
    ctxt->end = NULL;
    ctxt->start = ctxt->state = xmlRegNewState(ctxt);
    xmlRegStatePush(ctxt, ctxt->start);

    /* parse the expression building an automata */
    xmlFAParseRegExp(ctxt, 1);
    if (CUR != 0) {
      ERROR("xmlFAParseRegExp: extra characters");
    }
    if (ctxt->error != 0) {
      xmlRegFreeParserCtxt(ctxt);
      return(NULL);
    }
    ctxt->end = ctxt->state;
    ctxt->start->type = XML_REGEXP_START_STATE;
    ctxt->end->type = XML_REGEXP_FINAL_STATE;

    /* remove the Epsilon except for counted transitions */
    xmlFAEliminateEpsilonTransitions(ctxt);


    if (ctxt->error != 0) {
      xmlRegFreeParserCtxt(ctxt);
      return(NULL);
    }
    ret = xmlRegEpxFromParse(ctxt);
    xmlRegFreeParserCtxt(ctxt);
    return(ret);
}

/**
 * xmlRegexpExec:
 * @comp:  the compiled regular expression
 * @content:  the value to check against the regular expression
 *
 * Check if the regular expression generates the value
 *
 * Returns 1 if it matches, 0 if not and a negative value in case of error
 */
int
xmlRegexpExec(xmlRegexpPtr comp, const xmlChar *content) {
    if ((comp == NULL) || (content == NULL))
      return(-1);
    return(xmlFARegExec(comp, content));
}

/**
 * xmlRegexpIsDeterminist:
 * @comp:  the compiled regular expression
 *
 * Check if the regular expression is determinist
 *
 * Returns 1 if it yes, 0 if not and a negative value in case of error
 */
int
xmlRegexpIsDeterminist(xmlRegexpPtr comp) {
    xmlAutomataPtr am;
    int ret;

    if (comp == NULL)
      return(-1);
    if (comp->determinist != -1)
      return(comp->determinist);

    am = xmlNewAutomata();
    if (am->states != NULL) {
      int i;

      for (i = 0;i < am->nbStates;i++)
          xmlRegFreeState(am->states[i]);
      xmlFree(am->states);
    }
    am->nbAtoms = comp->nbAtoms;
    am->atoms = comp->atoms;
    am->nbStates = comp->nbStates;
    am->states = comp->states;
    am->determinist = -1;
    ret = xmlFAComputesDeterminism(am);
    am->atoms = NULL;
    am->states = NULL;
    xmlFreeAutomata(am);
    return(ret);
}

/**
 * xmlRegFreeRegexp:
 * @regexp:  the regexp
 *
 * Free a regexp
 */
void
xmlRegFreeRegexp(xmlRegexpPtr regexp) {
    int i;
    if (regexp == NULL)
      return;

    if (regexp->string != NULL)
      xmlFree(regexp->string);
    if (regexp->states != NULL) {
      for (i = 0;i < regexp->nbStates;i++)
          xmlRegFreeState(regexp->states[i]);
      xmlFree(regexp->states);
    }
    if (regexp->atoms != NULL) {
      for (i = 0;i < regexp->nbAtoms;i++)
          xmlRegFreeAtom(regexp->atoms[i]);
      xmlFree(regexp->atoms);
    }
    if (regexp->counters != NULL)
      xmlFree(regexp->counters);
    if (regexp->compact != NULL)
      xmlFree(regexp->compact);
    if (regexp->transdata != NULL)
      xmlFree(regexp->transdata);
    if (regexp->stringMap != NULL) {
      for (i = 0; i < regexp->nbstrings;i++)
          xmlFree(regexp->stringMap[i]);
      xmlFree(regexp->stringMap);
    }

    xmlFree(regexp);
}

#ifdef LIBXML_AUTOMATA_ENABLED
/************************************************************************
 *                                                    *
 *                The Automata interface                    *
 *                                                    *
 ************************************************************************/

/**
 * xmlNewAutomata:
 *
 * Create a new automata
 *
 * Returns the new object or NULL in case of failure
 */
xmlAutomataPtr
xmlNewAutomata(void) {
    xmlAutomataPtr ctxt;

    ctxt = xmlRegNewParserCtxt(NULL);
    if (ctxt == NULL)
      return(NULL);

    /* initialize the parser */
    ctxt->end = NULL;
    ctxt->start = ctxt->state = xmlRegNewState(ctxt);
    if (ctxt->start == NULL) {
      xmlFreeAutomata(ctxt);
      return(NULL);
    }
    ctxt->start->type = XML_REGEXP_START_STATE;
    if (xmlRegStatePush(ctxt, ctxt->start) < 0) {
        xmlRegFreeState(ctxt->start);
      xmlFreeAutomata(ctxt);
      return(NULL);
    }

    return(ctxt);
}

/**
 * xmlFreeAutomata:
 * @am: an automata
 *
 * Free an automata
 */
void
xmlFreeAutomata(xmlAutomataPtr am) {
    if (am == NULL)
      return;
    xmlRegFreeParserCtxt(am);
}

/**
 * xmlAutomataGetInitState:
 * @am: an automata
 *
 * Initial state lookup
 *
 * Returns the initial state of the automata
 */
xmlAutomataStatePtr
xmlAutomataGetInitState(xmlAutomataPtr am) {
    if (am == NULL)
      return(NULL);
    return(am->start);
}

/**
 * xmlAutomataSetFinalState:
 * @am: an automata
 * @state: a state in this automata
 *
 * Makes that state a final state
 *
 * Returns 0 or -1 in case of error
 */
int
xmlAutomataSetFinalState(xmlAutomataPtr am, xmlAutomataStatePtr state) {
    if ((am == NULL) || (state == NULL))
      return(-1);
    state->type = XML_REGEXP_FINAL_STATE;
    return(0);
}

/**
 * xmlAutomataNewTransition:
 * @am: an automata
 * @from: the starting point of the transition
 * @to: the target point of the transition or NULL
 * @token: the input string associated to that transition
 * @data: data passed to the callback function if the transition is activated
 *
 * If @to is NULL, this creates first a new target state in the automata
 * and then adds a transition from the @from state to the target state
 * activated by the value of @token
 *
 * Returns the target state or NULL in case of error
 */
xmlAutomataStatePtr
xmlAutomataNewTransition(xmlAutomataPtr am, xmlAutomataStatePtr from,
                   xmlAutomataStatePtr to, const xmlChar *token,
                   void *data) {
    xmlRegAtomPtr atom;

    if ((am == NULL) || (from == NULL) || (token == NULL))
      return(NULL);
    atom = xmlRegNewAtom(am, XML_REGEXP_STRING);
    if (atom == NULL)
        return(NULL);
    atom->data = data;
    if (atom == NULL)
      return(NULL);
    atom->valuep = xmlStrdup(token);

    if (xmlFAGenerateTransitions(am, from, to, atom) < 0) {
        xmlRegFreeAtom(atom);
      return(NULL);
    }
    if (to == NULL)
      return(am->state);
    return(to);
}

/**
 * xmlAutomataNewTransition2:
 * @am: an automata
 * @from: the starting point of the transition
 * @to: the target point of the transition or NULL
 * @token: the first input string associated to that transition
 * @token2: the second input string associated to that transition
 * @data: data passed to the callback function if the transition is activated
 *
 * If @to is NULL, this creates first a new target state in the automata
 * and then adds a transition from the @from state to the target state
 * activated by the value of @token
 *
 * Returns the target state or NULL in case of error
 */
xmlAutomataStatePtr
xmlAutomataNewTransition2(xmlAutomataPtr am, xmlAutomataStatePtr from,
                    xmlAutomataStatePtr to, const xmlChar *token,
                    const xmlChar *token2, void *data) {
    xmlRegAtomPtr atom;

    if ((am == NULL) || (from == NULL) || (token == NULL))
      return(NULL);
    atom = xmlRegNewAtom(am, XML_REGEXP_STRING);
    if (atom == NULL)
      return(NULL);
    atom->data = data;
    if ((token2 == NULL) || (*token2 == 0)) {
      atom->valuep = xmlStrdup(token);
    } else {
      int lenn, lenp;
      xmlChar *str;

      lenn = strlen((char *) token2);
      lenp = strlen((char *) token);

      str = (xmlChar *) xmlMallocAtomic(lenn + lenp + 2);
      if (str == NULL) {
          xmlRegFreeAtom(atom);
          return(NULL);
      }
      memcpy(&str[0], token, lenp);
      str[lenp] = '|';
      memcpy(&str[lenp + 1], token2, lenn);
      str[lenn + lenp + 1] = 0;

      atom->valuep = str;
    }

    if (xmlFAGenerateTransitions(am, from, to, atom) < 0) {
        xmlRegFreeAtom(atom);
      return(NULL);
    }
    if (to == NULL)
      return(am->state);
    return(to);
}

/**
 * xmlAutomataNewNegTrans:
 * @am: an automata
 * @from: the starting point of the transition
 * @to: the target point of the transition or NULL
 * @token: the first input string associated to that transition
 * @token2: the second input string associated to that transition
 * @data: data passed to the callback function if the transition is activated
 *
 * If @to is NULL, this creates first a new target state in the automata
 * and then adds a transition from the @from state to the target state
 * activated by any value except (@token,@token2)
 * Note that if @token2 is not NULL, then (X, NULL) won't match to follow
 # the semantic of XSD ##other
 *
 * Returns the target state or NULL in case of error
 */
xmlAutomataStatePtr
xmlAutomataNewNegTrans(xmlAutomataPtr am, xmlAutomataStatePtr from,
                   xmlAutomataStatePtr to, const xmlChar *token,
                   const xmlChar *token2, void *data) {
    xmlRegAtomPtr atom;
    xmlChar err_msg[200];

    if ((am == NULL) || (from == NULL) || (token == NULL))
      return(NULL);
    atom = xmlRegNewAtom(am, XML_REGEXP_STRING);
    if (atom == NULL)
      return(NULL);
    atom->data = data;
    atom->neg = 1;
    if ((token2 == NULL) || (*token2 == 0)) {
      atom->valuep = xmlStrdup(token);
    } else {
      int lenn, lenp;
      xmlChar *str;

      lenn = strlen((char *) token2);
      lenp = strlen((char *) token);

      str = (xmlChar *) xmlMallocAtomic(lenn + lenp + 2);
      if (str == NULL) {
          xmlRegFreeAtom(atom);
          return(NULL);
      }
      memcpy(&str[0], token, lenp);
      str[lenp] = '|';
      memcpy(&str[lenp + 1], token2, lenn);
      str[lenn + lenp + 1] = 0;

      atom->valuep = str;
    }
    snprintf((char *) err_msg, 199, "not %s", (const char *) atom->valuep);
    err_msg[199] = 0;
    atom->valuep2 = xmlStrdup(err_msg);

    if (xmlFAGenerateTransitions(am, from, to, atom) < 0) {
        xmlRegFreeAtom(atom);
      return(NULL);
    }
    am->negs++;
    if (to == NULL)
      return(am->state);
    return(to);
}

/**
 * xmlAutomataNewCountTrans2:
 * @am: an automata
 * @from: the starting point of the transition
 * @to: the target point of the transition or NULL
 * @token: the input string associated to that transition
 * @token2: the second input string associated to that transition
 * @min:  the minimum successive occurences of token
 * @max:  the maximum successive occurences of token
 * @data:  data associated to the transition
 *
 * If @to is NULL, this creates first a new target state in the automata
 * and then adds a transition from the @from state to the target state
 * activated by a succession of input of value @token and @token2 and 
 * whose number is between @min and @max
 *
 * Returns the target state or NULL in case of error
 */
xmlAutomataStatePtr
xmlAutomataNewCountTrans2(xmlAutomataPtr am, xmlAutomataStatePtr from,
                   xmlAutomataStatePtr to, const xmlChar *token,
                   const xmlChar *token2,
                   int min, int max, void *data) {
    xmlRegAtomPtr atom;
    int counter;

    if ((am == NULL) || (from == NULL) || (token == NULL))
      return(NULL);
    if (min < 0)
      return(NULL);
    if ((max < min) || (max < 1))
      return(NULL);
    atom = xmlRegNewAtom(am, XML_REGEXP_STRING);
    if (atom == NULL)
      return(NULL);
    if ((token2 == NULL) || (*token2 == 0)) {
      atom->valuep = xmlStrdup(token);
    } else {
      int lenn, lenp;
      xmlChar *str;

      lenn = strlen((char *) token2);
      lenp = strlen((char *) token);

      str = (xmlChar *) xmlMallocAtomic(lenn + lenp + 2);
      if (str == NULL) {
          xmlRegFreeAtom(atom);
          return(NULL);
      }
      memcpy(&str[0], token, lenp);
      str[lenp] = '|';
      memcpy(&str[lenp + 1], token2, lenn);
      str[lenn + lenp + 1] = 0;

      atom->valuep = str;
    }
    atom->data = data;
    if (min == 0)
      atom->min = 1;
    else
      atom->min = min;
    atom->max = max;

    /*
     * associate a counter to the transition.
     */
    counter = xmlRegGetCounter(am);
    am->counters[counter].min = min;
    am->counters[counter].max = max;

    /* xmlFAGenerateTransitions(am, from, to, atom); */
    if (to == NULL) {
        to = xmlRegNewState(am);
      xmlRegStatePush(am, to);
    }
    xmlRegStateAddTrans(am, from, atom, to, counter, -1);
    xmlRegAtomPush(am, atom);
    am->state = to;

    if (to == NULL)
      to = am->state;
    if (to == NULL)
      return(NULL);
    if (min == 0)
      xmlFAGenerateEpsilonTransition(am, from, to);
    return(to);
}

/**
 * xmlAutomataNewCountTrans:
 * @am: an automata
 * @from: the starting point of the transition
 * @to: the target point of the transition or NULL
 * @token: the input string associated to that transition
 * @min:  the minimum successive occurences of token
 * @max:  the maximum successive occurences of token
 * @data:  data associated to the transition
 *
 * If @to is NULL, this creates first a new target state in the automata
 * and then adds a transition from the @from state to the target state
 * activated by a succession of input of value @token and whose number
 * is between @min and @max
 *
 * Returns the target state or NULL in case of error
 */
xmlAutomataStatePtr
xmlAutomataNewCountTrans(xmlAutomataPtr am, xmlAutomataStatePtr from,
                   xmlAutomataStatePtr to, const xmlChar *token,
                   int min, int max, void *data) {
    xmlRegAtomPtr atom;
    int counter;

    if ((am == NULL) || (from == NULL) || (token == NULL))
      return(NULL);
    if (min < 0)
      return(NULL);
    if ((max < min) || (max < 1))
      return(NULL);
    atom = xmlRegNewAtom(am, XML_REGEXP_STRING);
    if (atom == NULL)
      return(NULL);
    atom->valuep = xmlStrdup(token);
    atom->data = data;
    if (min == 0)
      atom->min = 1;
    else
      atom->min = min;
    atom->max = max;

    /*
     * associate a counter to the transition.
     */
    counter = xmlRegGetCounter(am);
    am->counters[counter].min = min;
    am->counters[counter].max = max;

    /* xmlFAGenerateTransitions(am, from, to, atom); */
    if (to == NULL) {
        to = xmlRegNewState(am);
      xmlRegStatePush(am, to);
    }
    xmlRegStateAddTrans(am, from, atom, to, counter, -1);
    xmlRegAtomPush(am, atom);
    am->state = to;

    if (to == NULL)
      to = am->state;
    if (to == NULL)
      return(NULL);
    if (min == 0)
      xmlFAGenerateEpsilonTransition(am, from, to);
    return(to);
}

/**
 * xmlAutomataNewOnceTrans2:
 * @am: an automata
 * @from: the starting point of the transition
 * @to: the target point of the transition or NULL
 * @token: the input string associated to that transition
 * @token2: the second input string associated to that transition
 * @min:  the minimum successive occurences of token
 * @max:  the maximum successive occurences of token
 * @data:  data associated to the transition
 *
 * If @to is NULL, this creates first a new target state in the automata
 * and then adds a transition from the @from state to the target state
 * activated by a succession of input of value @token and @token2 and whose 
 * number is between @min and @max, moreover that transition can only be 
 * crossed once.
 *
 * Returns the target state or NULL in case of error
 */
xmlAutomataStatePtr
xmlAutomataNewOnceTrans2(xmlAutomataPtr am, xmlAutomataStatePtr from,
                   xmlAutomataStatePtr to, const xmlChar *token,
                   const xmlChar *token2,
                   int min, int max, void *data) {
    xmlRegAtomPtr atom;
    int counter;

    if ((am == NULL) || (from == NULL) || (token == NULL))
      return(NULL);
    if (min < 1)
      return(NULL);
    if ((max < min) || (max < 1))
      return(NULL);
    atom = xmlRegNewAtom(am, XML_REGEXP_STRING);
    if (atom == NULL)
      return(NULL);
    if ((token2 == NULL) || (*token2 == 0)) {
      atom->valuep = xmlStrdup(token);
    } else {
      int lenn, lenp;
      xmlChar *str;

      lenn = strlen((char *) token2);
      lenp = strlen((char *) token);

      str = (xmlChar *) xmlMallocAtomic(lenn + lenp + 2);
      if (str == NULL) {
          xmlRegFreeAtom(atom);
          return(NULL);
      }
      memcpy(&str[0], token, lenp);
      str[lenp] = '|';
      memcpy(&str[lenp + 1], token2, lenn);
      str[lenn + lenp + 1] = 0;

      atom->valuep = str;
    }    
    atom->data = data;
    atom->quant = XML_REGEXP_QUANT_ONCEONLY;
    atom->min = min;
    atom->max = max;
    /*
     * associate a counter to the transition.
     */
    counter = xmlRegGetCounter(am);
    am->counters[counter].min = 1;
    am->counters[counter].max = 1;

    /* xmlFAGenerateTransitions(am, from, to, atom); */
    if (to == NULL) {
      to = xmlRegNewState(am);
      xmlRegStatePush(am, to);
    }
    xmlRegStateAddTrans(am, from, atom, to, counter, -1);
    xmlRegAtomPush(am, atom);
    am->state = to;
    return(to);
}

    

/**
 * xmlAutomataNewOnceTrans:
 * @am: an automata
 * @from: the starting point of the transition
 * @to: the target point of the transition or NULL
 * @token: the input string associated to that transition
 * @min:  the minimum successive occurences of token
 * @max:  the maximum successive occurences of token
 * @data:  data associated to the transition
 *
 * If @to is NULL, this creates first a new target state in the automata
 * and then adds a transition from the @from state to the target state
 * activated by a succession of input of value @token and whose number
 * is between @min and @max, moreover that transition can only be crossed
 * once.
 *
 * Returns the target state or NULL in case of error
 */
xmlAutomataStatePtr
xmlAutomataNewOnceTrans(xmlAutomataPtr am, xmlAutomataStatePtr from,
                   xmlAutomataStatePtr to, const xmlChar *token,
                   int min, int max, void *data) {
    xmlRegAtomPtr atom;
    int counter;

    if ((am == NULL) || (from == NULL) || (token == NULL))
      return(NULL);
    if (min < 1)
      return(NULL);
    if ((max < min) || (max < 1))
      return(NULL);
    atom = xmlRegNewAtom(am, XML_REGEXP_STRING);
    if (atom == NULL)
      return(NULL);
    atom->valuep = xmlStrdup(token);
    atom->data = data;
    atom->quant = XML_REGEXP_QUANT_ONCEONLY;
    atom->min = min;
    atom->max = max;
    /*
     * associate a counter to the transition.
     */
    counter = xmlRegGetCounter(am);
    am->counters[counter].min = 1;
    am->counters[counter].max = 1;

    /* xmlFAGenerateTransitions(am, from, to, atom); */
    if (to == NULL) {
      to = xmlRegNewState(am);
      xmlRegStatePush(am, to);
    }
    xmlRegStateAddTrans(am, from, atom, to, counter, -1);
    xmlRegAtomPush(am, atom);
    am->state = to;
    return(to);
}

/**
 * xmlAutomataNewState:
 * @am: an automata
 *
 * Create a new disconnected state in the automata
 *
 * Returns the new state or NULL in case of error
 */
xmlAutomataStatePtr
xmlAutomataNewState(xmlAutomataPtr am) {
    xmlAutomataStatePtr to; 

    if (am == NULL)
      return(NULL);
    to = xmlRegNewState(am);
    xmlRegStatePush(am, to);
    return(to);
}

/**
 * xmlAutomataNewEpsilon:
 * @am: an automata
 * @from: the starting point of the transition
 * @to: the target point of the transition or NULL
 *
 * If @to is NULL, this creates first a new target state in the automata
 * and then adds an epsilon transition from the @from state to the
 * target state
 *
 * Returns the target state or NULL in case of error
 */
xmlAutomataStatePtr
xmlAutomataNewEpsilon(xmlAutomataPtr am, xmlAutomataStatePtr from,
                  xmlAutomataStatePtr to) {
    if ((am == NULL) || (from == NULL))
      return(NULL);
    xmlFAGenerateEpsilonTransition(am, from, to);
    if (to == NULL)
      return(am->state);
    return(to);
}

/**
 * xmlAutomataNewAllTrans:
 * @am: an automata
 * @from: the starting point of the transition
 * @to: the target point of the transition or NULL
 * @lax: allow to transition if not all all transitions have been activated
 *
 * If @to is NULL, this creates first a new target state in the automata
 * and then adds a an ALL transition from the @from state to the
 * target state. That transition is an epsilon transition allowed only when
 * all transitions from the @from node have been activated.
 *
 * Returns the target state or NULL in case of error
 */
xmlAutomataStatePtr
xmlAutomataNewAllTrans(xmlAutomataPtr am, xmlAutomataStatePtr from,
                   xmlAutomataStatePtr to, int lax) {
    if ((am == NULL) || (from == NULL))
      return(NULL);
    xmlFAGenerateAllTransition(am, from, to, lax);
    if (to == NULL)
      return(am->state);
    return(to);
}

/**
 * xmlAutomataNewCounter:
 * @am: an automata
 * @min:  the minimal value on the counter
 * @max:  the maximal value on the counter
 *
 * Create a new counter
 *
 * Returns the counter number or -1 in case of error
 */
int         
xmlAutomataNewCounter(xmlAutomataPtr am, int min, int max) {
    int ret;

    if (am == NULL)
      return(-1);

    ret = xmlRegGetCounter(am);
    if (ret < 0)
      return(-1);
    am->counters[ret].min = min;
    am->counters[ret].max = max;
    return(ret);
}

/**
 * xmlAutomataNewCountedTrans:
 * @am: an automata
 * @from: the starting point of the transition
 * @to: the target point of the transition or NULL
 * @counter: the counter associated to that transition
 *
 * If @to is NULL, this creates first a new target state in the automata
 * and then adds an epsilon transition from the @from state to the target state
 * which will increment the counter provided
 *
 * Returns the target state or NULL in case of error
 */
xmlAutomataStatePtr
xmlAutomataNewCountedTrans(xmlAutomataPtr am, xmlAutomataStatePtr from,
            xmlAutomataStatePtr to, int counter) {
    if ((am == NULL) || (from == NULL) || (counter < 0))
      return(NULL);
    xmlFAGenerateCountedEpsilonTransition(am, from, to, counter);
    if (to == NULL)
      return(am->state);
    return(to);
}

/**
 * xmlAutomataNewCounterTrans:
 * @am: an automata
 * @from: the starting point of the transition
 * @to: the target point of the transition or NULL
 * @counter: the counter associated to that transition
 *
 * If @to is NULL, this creates first a new target state in the automata
 * and then adds an epsilon transition from the @from state to the target state
 * which will be allowed only if the counter is within the right range.
 *
 * Returns the target state or NULL in case of error
 */
xmlAutomataStatePtr
xmlAutomataNewCounterTrans(xmlAutomataPtr am, xmlAutomataStatePtr from,
            xmlAutomataStatePtr to, int counter) {
    if ((am == NULL) || (from == NULL) || (counter < 0))
      return(NULL);
    xmlFAGenerateCountedTransition(am, from, to, counter);
    if (to == NULL)
      return(am->state);
    return(to);
}

/**
 * xmlAutomataCompile:
 * @am: an automata
 *
 * Compile the automata into a Reg Exp ready for being executed.
 * The automata should be free after this point.
 *
 * Returns the compiled regexp or NULL in case of error
 */
xmlRegexpPtr          
xmlAutomataCompile(xmlAutomataPtr am) {
    xmlRegexpPtr ret;

    if ((am == NULL) || (am->error != 0)) return(NULL);
    xmlFAEliminateEpsilonTransitions(am);
    /* xmlFAComputesDeterminism(am); */
    ret = xmlRegEpxFromParse(am);

    return(ret);
}

/**
 * xmlAutomataIsDeterminist:
 * @am: an automata
 *
 * Checks if an automata is determinist.
 *
 * Returns 1 if true, 0 if not, and -1 in case of error
 */
int          
xmlAutomataIsDeterminist(xmlAutomataPtr am) {
    int ret;

    if (am == NULL)
      return(-1);

    ret = xmlFAComputesDeterminism(am);
    return(ret);
}
#endif /* LIBXML_AUTOMATA_ENABLED */

#ifdef LIBXML_EXPR_ENABLED
/************************************************************************
 *                                                    *
 *          Formal Expression handling code                       *
 *                                                    *
 ************************************************************************/
/************************************************************************
 *                                                    *
 *          Expression handling context                     *
 *                                                    *
 ************************************************************************/

struct _xmlExpCtxt {
    xmlDictPtr dict;
    xmlExpNodePtr *table;
    int size;
    int nbElems;
    int nb_nodes;
    const char *expr;
    const char *cur;
    int nb_cons;
    int tabSize;
};

/**
 * xmlExpNewCtxt:
 * @maxNodes:  the maximum number of nodes
 * @dict:  optional dictionnary to use internally
 *
 * Creates a new context for manipulating expressions
 *
 * Returns the context or NULL in case of error
 */
xmlExpCtxtPtr
xmlExpNewCtxt(int maxNodes, xmlDictPtr dict) {
    xmlExpCtxtPtr ret;
    int size = 256;

    if (maxNodes <= 4096)
        maxNodes = 4096;
    
    ret = (xmlExpCtxtPtr) xmlMalloc(sizeof(xmlExpCtxt));
    if (ret == NULL)
        return(NULL);
    memset(ret, 0, sizeof(xmlExpCtxt));
    ret->size = size;
    ret->nbElems = 0;
    ret->table = xmlMalloc(size * sizeof(xmlExpNodePtr));
    if (ret->table == NULL) {
        xmlFree(ret);
      return(NULL);
    }
    memset(ret->table, 0, size * sizeof(xmlExpNodePtr));
    if (dict == NULL) {
        ret->dict = xmlDictCreate();
      if (ret->dict == NULL) {
          xmlFree(ret->table);
          xmlFree(ret);
          return(NULL);
      }
    } else {
        ret->dict = dict;
      xmlDictReference(ret->dict);
    }
    return(ret);
}

/**
 * xmlExpFreeCtxt:
 * @ctxt:  an expression context
 *
 * Free an expression context
 */
void
xmlExpFreeCtxt(xmlExpCtxtPtr ctxt) {
    if (ctxt == NULL)
        return;
    xmlDictFree(ctxt->dict);
    if (ctxt->table != NULL)
      xmlFree(ctxt->table);
    xmlFree(ctxt);
}

/************************************************************************
 *                                                    *
 *          Structure associated to an expression node            *
 *                                                    *
 ************************************************************************/
#define MAX_NODES 10000

/* #define DEBUG_DERIV */

/*
 * TODO: 
 * - Wildcards
 * - public API for creation
 *
 * Started
 * - regression testing
 *
 * Done
 * - split into module and test tool
 * - memleaks
 */

typedef enum {
    XML_EXP_NILABLE = (1 << 0)
} xmlExpNodeInfo;

#define IS_NILLABLE(node) ((node)->info & XML_EXP_NILABLE)

struct _xmlExpNode {
    unsigned char type;/* xmlExpNodeType */
    unsigned char info;/* OR of xmlExpNodeInfo */
    unsigned short key; /* the hash key */
    unsigned int ref;   /* The number of references */
    int c_max;          /* the maximum length it can consume */
    xmlExpNodePtr exp_left;
    xmlExpNodePtr next;/* the next node in the hash table or free list */
    union {
      struct {
          int f_min;
          int f_max;
      } count;
      struct {
          xmlExpNodePtr f_right;
      } children;
        const xmlChar *f_str;
    } field;
};

#define exp_min field.count.f_min
#define exp_max field.count.f_max
/* #define exp_left field.children.f_left */
#define exp_right field.children.f_right
#define exp_str field.f_str

static xmlExpNodePtr xmlExpNewNode(xmlExpCtxtPtr ctxt, xmlExpNodeType type);
static xmlExpNode forbiddenExpNode = {
    XML_EXP_FORBID, 0, 0, 0, 0, NULL, NULL, {{ 0, 0}}
};
xmlExpNodePtr forbiddenExp = &forbiddenExpNode;
static xmlExpNode emptyExpNode = {
    XML_EXP_EMPTY, 1, 0, 0, 0, NULL, NULL, {{ 0, 0}}
};
xmlExpNodePtr emptyExp = &emptyExpNode;

/************************************************************************
 *                                                    *
 *  The custom hash table for unicity and canonicalization        *
 *  of sub-expressions pointers                                   *
 *                                                    *
 ************************************************************************/
/*
 * xmlExpHashNameComputeKey:
 * Calculate the hash key for a token
 */
static unsigned short
xmlExpHashNameComputeKey(const xmlChar *name) {
    unsigned short value = 0L;
    char ch;
    
    if (name != NULL) {
      value += 30 * (*name);
      while ((ch = *name++) != 0) {
          value = value ^ ((value << 5) + (value >> 3) + (unsigned short)ch);
      }
    }
    return (value);
}

/*
 * xmlExpHashComputeKey:
 * Calculate the hash key for a compound expression
 */
static unsigned short
xmlExpHashComputeKey(xmlExpNodeType type, xmlExpNodePtr left,
                     xmlExpNodePtr right) {
    unsigned long value;
    unsigned short ret;
    
    switch (type) {
        case XML_EXP_SEQ:
          value = left->key;
          value += right->key;
          value *= 3;
          ret = (unsigned short) value;
          break;
        case XML_EXP_OR:
          value = left->key;
          value += right->key;
          value *= 7;
          ret = (unsigned short) value;
          break;
        case XML_EXP_COUNT:
          value = left->key;
          value += right->key;
          ret = (unsigned short) value;
          break;
      default:
          ret = 0;
    }
    return(ret);
}


static xmlExpNodePtr
xmlExpNewNode(xmlExpCtxtPtr ctxt, xmlExpNodeType type) {
    xmlExpNodePtr ret;

    if (ctxt->nb_nodes >= MAX_NODES)
        return(NULL);
    ret = (xmlExpNodePtr) xmlMalloc(sizeof(xmlExpNode));
    if (ret == NULL)
        return(NULL);
    memset(ret, 0, sizeof(xmlExpNode));
    ret->type = type;
    ret->next = NULL;
    ctxt->nb_nodes++;
    ctxt->nb_cons++;
    return(ret);
}

/**
 * xmlExpHashGetEntry:
 * @table: the hash table
 *
 * Get the unique entry from the hash table. The entry is created if
 * needed. @left and @right are consumed, i.e. their ref count will
 * be decremented by the operation.
 *
 * Returns the pointer or NULL in case of error
 */
static xmlExpNodePtr
xmlExpHashGetEntry(xmlExpCtxtPtr ctxt, xmlExpNodeType type,
                   xmlExpNodePtr left, xmlExpNodePtr right,
               const xmlChar *name, int min, int max) {
    unsigned short kbase, key;
    xmlExpNodePtr entry;
    xmlExpNodePtr insert;

    if (ctxt == NULL)
      return(NULL);

    /*
     * Check for duplicate and insertion location.
     */
    if (type == XML_EXP_ATOM) {
      kbase = xmlExpHashNameComputeKey(name);
    } else if (type == XML_EXP_COUNT) {
        /* COUNT reduction rule 1 */
      /* a{1} -> a */
      if (min == max) {
          if (min == 1) {
            return(left);
          }
          if (min == 0) {
            xmlExpFree(ctxt, left);
              return(emptyExp);
          }
      }
      if (min < 0) {
          xmlExpFree(ctxt, left);
          return(forbiddenExp);
      }
        if (max == -1)
          kbase = min + 79;
      else
          kbase = max - min;
      kbase += left->key;
    } else if (type == XML_EXP_OR) {
        /* Forbid reduction rules */
        if (left->type == XML_EXP_FORBID) {
          xmlExpFree(ctxt, left);
          return(right);
      }
        if (right->type == XML_EXP_FORBID) {
          xmlExpFree(ctxt, right);
          return(left);
      }

        /* OR reduction rule 1 */
      /* a | a reduced to a */
        if (left == right) {
          left->ref--;
          return(left);
      }
        /* OR canonicalization rule 1 */
      /* linearize (a | b) | c into a | (b | c) */
        if ((left->type == XML_EXP_OR) && (right->type != XML_EXP_OR)) {
          xmlExpNodePtr tmp = left;
            left = right;
          right = tmp;
      }
        /* OR reduction rule 2 */
      /* a | (a | b) and b | (a | b) are reduced to a | b */
        if (right->type == XML_EXP_OR) {
          if ((left == right->exp_left) ||
              (left == right->exp_right)) {
            xmlExpFree(ctxt, left);
            return(right);
          }
      }
        /* OR canonicalization rule 2 */
      /* linearize (a | b) | c into a | (b | c) */
        if (left->type == XML_EXP_OR) {
          xmlExpNodePtr tmp;

          /* OR canonicalization rule 2 */
          if ((left->exp_right->type != XML_EXP_OR) &&
              (left->exp_right->key < left->exp_left->key)) {
              tmp = left->exp_right;
            left->exp_right = left->exp_left;
            left->exp_left = tmp;
          }
          left->exp_right->ref++;
          tmp = xmlExpHashGetEntry(ctxt, XML_EXP_OR, left->exp_right, right,
                                   NULL, 0, 0);
          left->exp_left->ref++;
          tmp = xmlExpHashGetEntry(ctxt, XML_EXP_OR, left->exp_left, tmp,
                                   NULL, 0, 0);
      
          xmlExpFree(ctxt, left);
          return(tmp);
      }
      if (right->type == XML_EXP_OR) {
          /* Ordering in the tree */
          /* C | (A | B) -> A | (B | C) */
          if (left->key > right->exp_right->key) {
            xmlExpNodePtr tmp;
            right->exp_right->ref++;
            tmp = xmlExpHashGetEntry(ctxt, XML_EXP_OR, right->exp_right,
                                     left, NULL, 0, 0);
            right->exp_left->ref++;
            tmp = xmlExpHashGetEntry(ctxt, XML_EXP_OR, right->exp_left,
                                     tmp, NULL, 0, 0);
            xmlExpFree(ctxt, right);
            return(tmp);
          }
          /* Ordering in the tree */
          /* B | (A | C) -> A | (B | C) */
          if (left->key > right->exp_left->key) {
            xmlExpNodePtr tmp;
            right->exp_right->ref++;
            tmp = xmlExpHashGetEntry(ctxt, XML_EXP_OR, left,
                                     right->exp_right, NULL, 0, 0);
            right->exp_left->ref++;
            tmp = xmlExpHashGetEntry(ctxt, XML_EXP_OR, right->exp_left,
                                     tmp, NULL, 0, 0);
            xmlExpFree(ctxt, right);
            return(tmp);
          }
      }
      /* we know both types are != XML_EXP_OR here */
        else if (left->key > right->key) {
          xmlExpNodePtr tmp = left;
            left = right;
          right = tmp;
      }
      kbase = xmlExpHashComputeKey(type, left, right);
    } else if (type == XML_EXP_SEQ) {
        /* Forbid reduction rules */
        if (left->type == XML_EXP_FORBID) {
          xmlExpFree(ctxt, right);
          return(left);
      }
        if (right->type == XML_EXP_FORBID) {
          xmlExpFree(ctxt, left);
          return(right);
      }
        /* Empty reduction rules */
        if (right->type == XML_EXP_EMPTY) {
          return(left);
      }
        if (left->type == XML_EXP_EMPTY) {
          return(right);
      }
      kbase = xmlExpHashComputeKey(type, left, right);
    } else 
        return(NULL);

    key = kbase % ctxt->size;
    if (ctxt->table[key] != NULL) {
      for (insert = ctxt->table[key]; insert != NULL;
           insert = insert->next) {
          if ((insert->key == kbase) &&
              (insert->type == type)) {
            if (type == XML_EXP_ATOM) {
                if (name == insert->exp_str) {
                  insert->ref++;
                  return(insert);
                }
            } else if (type == XML_EXP_COUNT) {
                if ((insert->exp_min == min) && (insert->exp_max == max) &&
                    (insert->exp_left == left)) {
                  insert->ref++;
                  left->ref--;
                  return(insert);
                }
            } else if ((insert->exp_left == left) &&
                     (insert->exp_right == right)) {
                insert->ref++;
                left->ref--;
                right->ref--;
                return(insert);
            }
          }
      }
    }

    entry = xmlExpNewNode(ctxt, type);
    if (entry == NULL)
        return(NULL);
    entry->key = kbase;
    if (type == XML_EXP_ATOM) {
      entry->exp_str = name;
      entry->c_max = 1;
    } else if (type == XML_EXP_COUNT) {
        entry->exp_min = min;
        entry->exp_max = max;
      entry->exp_left = left;
      if ((min == 0) || (IS_NILLABLE(left)))
          entry->info |= XML_EXP_NILABLE;
      if (max < 0)
          entry->c_max = -1;
      else
          entry->c_max = max * entry->exp_left->c_max;
    } else {
      entry->exp_left = left;
      entry->exp_right = right;
      if (type == XML_EXP_OR) {
          if ((IS_NILLABLE(left)) || (IS_NILLABLE(right)))
            entry->info |= XML_EXP_NILABLE;
          if ((entry->exp_left->c_max == -1) ||
              (entry->exp_right->c_max == -1))
            entry->c_max = -1;
          else if (entry->exp_left->c_max > entry->exp_right->c_max)
              entry->c_max = entry->exp_left->c_max;
          else
              entry->c_max = entry->exp_right->c_max;
      } else {
          if ((IS_NILLABLE(left)) && (IS_NILLABLE(right)))
            entry->info |= XML_EXP_NILABLE;
          if ((entry->exp_left->c_max == -1) ||
              (entry->exp_right->c_max == -1))
            entry->c_max = -1;
          else
              entry->c_max = entry->exp_left->c_max + entry->exp_right->c_max;
      }
    }
    entry->ref = 1;
    if (ctxt->table[key] != NULL)
        entry->next = ctxt->table[key];

    ctxt->table[key] = entry;
    ctxt->nbElems++;

    return(entry);
}

/**
 * xmlExpFree:
 * @ctxt: the expression context
 * @exp: the expression
 *
 * Dereference the expression
 */
void
xmlExpFree(xmlExpCtxtPtr ctxt, xmlExpNodePtr exp) {
    if ((exp == NULL) || (exp == forbiddenExp) || (exp == emptyExp))
        return;
    exp->ref--;
    if (exp->ref == 0) {
        unsigned short key;

        /* Unlink it first from the hash table */
      key = exp->key % ctxt->size;
      if (ctxt->table[key] == exp) {
          ctxt->table[key] = exp->next;
      } else {
          xmlExpNodePtr tmp;

          tmp = ctxt->table[key];
          while (tmp != NULL) {
              if (tmp->next == exp) {
                tmp->next = exp->next;
                break;
            }
              tmp = tmp->next;
          }
      }

        if ((exp->type == XML_EXP_SEQ) || (exp->type == XML_EXP_OR)) {
          xmlExpFree(ctxt, exp->exp_left);
          xmlExpFree(ctxt, exp->exp_right);
      } else if (exp->type == XML_EXP_COUNT) {
          xmlExpFree(ctxt, exp->exp_left);
      }
        xmlFree(exp);
      ctxt->nb_nodes--;
    }
}

/**
 * xmlExpRef:
 * @exp: the expression
 *
 * Increase the reference count of the expression
 */
void
xmlExpRef(xmlExpNodePtr exp) {
    if (exp != NULL)
        exp->ref++;
}

/**
 * xmlExpNewAtom:
 * @ctxt: the expression context
 * @name: the atom name
 * @len: the atom name lenght in byte (or -1);
 *
 * Get the atom associated to this name from that context
 *
 * Returns the node or NULL in case of error
 */
xmlExpNodePtr
xmlExpNewAtom(xmlExpCtxtPtr ctxt, const xmlChar *name, int len) {
    if ((ctxt == NULL) || (name == NULL))
        return(NULL);
    name = xmlDictLookup(ctxt->dict, name, len);
    if (name == NULL)
        return(NULL);
    return(xmlExpHashGetEntry(ctxt, XML_EXP_ATOM, NULL, NULL, name, 0, 0));
}

/**
 * xmlExpNewOr:
 * @ctxt: the expression context
 * @left: left expression
 * @right: right expression
 *
 * Get the atom associated to the choice @left | @right
 * Note that @left and @right are consumed in the operation, to keep
 * an handle on them use xmlExpRef() and use xmlExpFree() to release them,
 * this is true even in case of failure (unless ctxt == NULL).
 *
 * Returns the node or NULL in case of error
 */
xmlExpNodePtr
xmlExpNewOr(xmlExpCtxtPtr ctxt, xmlExpNodePtr left, xmlExpNodePtr right) {
    if (ctxt == NULL)
        return(NULL);
    if ((left == NULL) || (right == NULL)) {
        xmlExpFree(ctxt, left);
        xmlExpFree(ctxt, right);
        return(NULL);
    }
    return(xmlExpHashGetEntry(ctxt, XML_EXP_OR, left, right, NULL, 0, 0));
}

/**
 * xmlExpNewSeq:
 * @ctxt: the expression context
 * @left: left expression
 * @right: right expression
 *
 * Get the atom associated to the sequence @left , @right
 * Note that @left and @right are consumed in the operation, to keep
 * an handle on them use xmlExpRef() and use xmlExpFree() to release them,
 * this is true even in case of failure (unless ctxt == NULL).
 *
 * Returns the node or NULL in case of error
 */
xmlExpNodePtr
xmlExpNewSeq(xmlExpCtxtPtr ctxt, xmlExpNodePtr left, xmlExpNodePtr right) {
    if (ctxt == NULL)
        return(NULL);
    if ((left == NULL) || (right == NULL)) {
        xmlExpFree(ctxt, left);
        xmlExpFree(ctxt, right);
        return(NULL);
    }
    return(xmlExpHashGetEntry(ctxt, XML_EXP_SEQ, left, right, NULL, 0, 0));
}

/**
 * xmlExpNewRange:
 * @ctxt: the expression context
 * @subset: the expression to be repeated
 * @min: the lower bound for the repetition
 * @max: the upper bound for the repetition, -1 means infinite
 *
 * Get the atom associated to the range (@subset){@min, @max}
 * Note that @subset is consumed in the operation, to keep
 * an handle on it use xmlExpRef() and use xmlExpFree() to release it,
 * this is true even in case of failure (unless ctxt == NULL).
 *
 * Returns the node or NULL in case of error
 */
xmlExpNodePtr
xmlExpNewRange(xmlExpCtxtPtr ctxt, xmlExpNodePtr subset, int min, int max) {
    if (ctxt == NULL)
        return(NULL);
    if ((subset == NULL) || (min < 0) || (max < -1) ||
        ((max >= 0) && (min > max))) {
      xmlExpFree(ctxt, subset);
        return(NULL);
    }
    return(xmlExpHashGetEntry(ctxt, XML_EXP_COUNT, subset,
                              NULL, NULL, min, max));
}

/************************************************************************
 *                                                    *
 *          Public API for operations on expressions        *
 *                                                    *
 ************************************************************************/

static int
xmlExpGetLanguageInt(xmlExpCtxtPtr ctxt, xmlExpNodePtr exp, 
                     const xmlChar**list, int len, int nb) {
    int tmp, tmp2;
tail:
    switch (exp->type) {
        case XML_EXP_EMPTY:
          return(0);
        case XML_EXP_ATOM:
          for (tmp = 0;tmp < nb;tmp++)
              if (list[tmp] == exp->exp_str)
                return(0);
            if (nb >= len)
              return(-2);
          list[nb++] = exp->exp_str;
          return(1);
        case XML_EXP_COUNT:
          exp = exp->exp_left;
          goto tail;
        case XML_EXP_SEQ:
        case XML_EXP_OR:
          tmp = xmlExpGetLanguageInt(ctxt, exp->exp_left, list, len, nb);
          if (tmp < 0)
              return(tmp);
          tmp2 = xmlExpGetLanguageInt(ctxt, exp->exp_right, list, len,
                                      nb + tmp);
          if (tmp2 < 0)
              return(tmp2);
            return(tmp + tmp2);
    }
    return(-1);
}

/**
 * xmlExpGetLanguage:
 * @ctxt: the expression context
 * @exp: the expression
 * @langList: where to store the tokens
 * @len: the allocated lenght of @list
 *
 * Find all the strings used in @exp and store them in @list
 *
 * Returns the number of unique strings found, -1 in case of errors and
 *         -2 if there is more than @len strings
 */
int
xmlExpGetLanguage(xmlExpCtxtPtr ctxt, xmlExpNodePtr exp, 
                  const xmlChar**langList, int len) {
    if ((ctxt == NULL) || (exp == NULL) || (langList == NULL) || (len <= 0))
        return(-1);
    return(xmlExpGetLanguageInt(ctxt, exp, langList, len, 0));
}

static int
xmlExpGetStartInt(xmlExpCtxtPtr ctxt, xmlExpNodePtr exp, 
                  const xmlChar**list, int len, int nb) {
    int tmp, tmp2;
tail:
    switch (exp->type) {
        case XML_EXP_FORBID:
          return(0);
        case XML_EXP_EMPTY:
          return(0);
        case XML_EXP_ATOM:
          for (tmp = 0;tmp < nb;tmp++)
              if (list[tmp] == exp->exp_str)
                return(0);
            if (nb >= len)
              return(-2);
          list[nb++] = exp->exp_str;
          return(1);
        case XML_EXP_COUNT:
          exp = exp->exp_left;
          goto tail;
        case XML_EXP_SEQ:
          tmp = xmlExpGetStartInt(ctxt, exp->exp_left, list, len, nb);
          if (tmp < 0)
              return(tmp);
          if (IS_NILLABLE(exp->exp_left)) {
            tmp2 = xmlExpGetStartInt(ctxt, exp->exp_right, list, len,
                                  nb + tmp);
            if (tmp2 < 0)
                return(tmp2);
            tmp += tmp2;
          }
            return(tmp);
        case XML_EXP_OR:
          tmp = xmlExpGetStartInt(ctxt, exp->exp_left, list, len, nb);
          if (tmp < 0)
              return(tmp);
          tmp2 = xmlExpGetStartInt(ctxt, exp->exp_right, list, len,
                                      nb + tmp);
          if (tmp2 < 0)
              return(tmp2);
            return(tmp + tmp2);
    }
    return(-1);
}

/**
 * xmlExpGetStart:
 * @ctxt: the expression context
 * @exp: the expression
 * @tokList: where to store the tokens
 * @len: the allocated lenght of @list
 *
 * Find all the strings that appears at the start of the languages
 * accepted by @exp and store them in @list. E.g. for (a, b) | c
 * it will return the list [a, c]
 *
 * Returns the number of unique strings found, -1 in case of errors and
 *         -2 if there is more than @len strings
 */
int
xmlExpGetStart(xmlExpCtxtPtr ctxt, xmlExpNodePtr exp, 
               const xmlChar**tokList, int len) {
    if ((ctxt == NULL) || (exp == NULL) || (tokList == NULL) || (len <= 0))
        return(-1);
    return(xmlExpGetStartInt(ctxt, exp, tokList, len, 0));
}

/**
 * xmlExpIsNillable:
 * @exp: the expression
 *
 * Finds if the expression is nillable, i.e. if it accepts the empty sequqnce
 *
 * Returns 1 if nillable, 0 if not and -1 in case of error
 */
int
xmlExpIsNillable(xmlExpNodePtr exp) {
    if (exp == NULL)
        return(-1);
    return(IS_NILLABLE(exp) != 0);
}

static xmlExpNodePtr
xmlExpStringDeriveInt(xmlExpCtxtPtr ctxt, xmlExpNodePtr exp, const xmlChar *str)
{
    xmlExpNodePtr ret;

    switch (exp->type) {
      case XML_EXP_EMPTY:
          return(forbiddenExp);
      case XML_EXP_FORBID:
          return(forbiddenExp);
      case XML_EXP_ATOM:
          if (exp->exp_str == str) {
#ifdef DEBUG_DERIV
            printf("deriv atom: equal => Empty\n");
#endif
              ret = emptyExp;
          } else {
#ifdef DEBUG_DERIV
            printf("deriv atom: mismatch => forbid\n");
#endif
              /* TODO wildcards here */
            ret = forbiddenExp;
          }
          return(ret);
      case XML_EXP_OR: {
          xmlExpNodePtr tmp;

#ifdef DEBUG_DERIV
          printf("deriv or: => or(derivs)\n");
#endif
          tmp = xmlExpStringDeriveInt(ctxt, exp->exp_left, str);
          if (tmp == NULL) {
            return(NULL);
          }
          ret = xmlExpStringDeriveInt(ctxt, exp->exp_right, str);
          if (ret == NULL) {
              xmlExpFree(ctxt, tmp);
            return(NULL);
          }
            ret = xmlExpHashGetEntry(ctxt, XML_EXP_OR, tmp, ret,
                       NULL, 0, 0);
          return(ret);
      }
      case XML_EXP_SEQ:
#ifdef DEBUG_DERIV
          printf("deriv seq: starting with left\n");
#endif
          ret = xmlExpStringDeriveInt(ctxt, exp->exp_left, str);
          if (ret == NULL) {
              return(NULL);
          } else if (ret == forbiddenExp) {
              if (IS_NILLABLE(exp->exp_left)) {
#ifdef DEBUG_DERIV
                printf("deriv seq: left failed but nillable\n");
#endif
                ret = xmlExpStringDeriveInt(ctxt, exp->exp_right, str);
            }
          } else {
#ifdef DEBUG_DERIV
            printf("deriv seq: left match => sequence\n");
#endif
              exp->exp_right->ref++;
              ret = xmlExpHashGetEntry(ctxt, XML_EXP_SEQ, ret, exp->exp_right,
                                     NULL, 0, 0);
          }
          return(ret);
      case XML_EXP_COUNT: {
          int min, max;
          xmlExpNodePtr tmp;

          if (exp->exp_max == 0)
            return(forbiddenExp);
          ret = xmlExpStringDeriveInt(ctxt, exp->exp_left, str);
          if (ret == NULL)
              return(NULL);
          if (ret == forbiddenExp) {
#ifdef DEBUG_DERIV
            printf("deriv count: pattern mismatch => forbid\n");
#endif
              return(ret);
          }
          if (exp->exp_max == 1)
            return(ret);
          if (exp->exp_max < 0) /* unbounded */
            max = -1;
          else
            max = exp->exp_max - 1;
          if (exp->exp_min > 0)
            min = exp->exp_min - 1;
          else
            min = 0;
          exp->exp_left->ref++;
          tmp = xmlExpHashGetEntry(ctxt, XML_EXP_COUNT, exp->exp_left, NULL,
                             NULL, min, max);
          if (ret == emptyExp) {
#ifdef DEBUG_DERIV
            printf("deriv count: match to empty => new count\n");
#endif
              return(tmp);
          }
#ifdef DEBUG_DERIV
          printf("deriv count: match => sequence with new count\n");
#endif
          return(xmlExpHashGetEntry(ctxt, XML_EXP_SEQ, ret, tmp,
                                    NULL, 0, 0));
      }
    }
    return(NULL);
}

/**
 * xmlExpStringDerive:
 * @ctxt: the expression context
 * @exp: the expression
 * @str: the string
 * @len: the string len in bytes if available
 *
 * Do one step of Brzozowski derivation of the expression @exp with
 * respect to the input string
 *
 * Returns the resulting expression or NULL in case of internal error
 */
xmlExpNodePtr
xmlExpStringDerive(xmlExpCtxtPtr ctxt, xmlExpNodePtr exp,
                   const xmlChar *str, int len) {
    const xmlChar *input;

    if ((exp == NULL) || (ctxt == NULL) || (str == NULL)) {
        return(NULL);
    }
    /*
     * check the string is in the dictionnary, if yes use an interned
     * copy, otherwise we know it's not an acceptable input
     */
    input = xmlDictExists(ctxt->dict, str, len);
    if (input == NULL) {
        return(forbiddenExp);
    }
    return(xmlExpStringDeriveInt(ctxt, exp, input));
}

static int
xmlExpCheckCard(xmlExpNodePtr exp, xmlExpNodePtr sub) {
    int ret = 1;

    if (sub->c_max == -1) {
        if (exp->c_max != -1)
          ret = 0;
    } else if ((exp->c_max >= 0) && (exp->c_max < sub->c_max)) {
        ret = 0;
    }
#if 0
    if ((IS_NILLABLE(sub)) && (!IS_NILLABLE(exp)))
        ret = 0;
#endif
    return(ret);
}

static xmlExpNodePtr xmlExpExpDeriveInt(xmlExpCtxtPtr ctxt, xmlExpNodePtr exp,
                                        xmlExpNodePtr sub);
/**
 * xmlExpDivide:
 * @ctxt: the expressions context
 * @exp: the englobing expression
 * @sub: the subexpression
 * @mult: the multiple expression
 * @remain: the remain from the derivation of the multiple
 *
 * Check if exp is a multiple of sub, i.e. if there is a finite number n
 * so that sub{n} subsume exp
 *
 * Returns the multiple value if successful, 0 if it is not a multiple
 *         and -1 in case of internel error.
 */

static int
xmlExpDivide(xmlExpCtxtPtr ctxt, xmlExpNodePtr exp, xmlExpNodePtr sub,
             xmlExpNodePtr *mult, xmlExpNodePtr *remain) {
    int i;
    xmlExpNodePtr tmp, tmp2;

    if (mult != NULL) *mult = NULL;
    if (remain != NULL) *remain = NULL;
    if (exp->c_max == -1) return(0);
    if (IS_NILLABLE(exp) && (!IS_NILLABLE(sub))) return(0);

    for (i = 1;i <= exp->c_max;i++) {
        sub->ref++;
        tmp = xmlExpHashGetEntry(ctxt, XML_EXP_COUNT,
                         sub, NULL, NULL, i, i);
      if (tmp == NULL) {
          return(-1);
      }
      if (!xmlExpCheckCard(tmp, exp)) {
          xmlExpFree(ctxt, tmp);
          continue;
      }
      tmp2 = xmlExpExpDeriveInt(ctxt, tmp, exp);
      if (tmp2 == NULL) {
          xmlExpFree(ctxt, tmp);
          return(-1);
      }
      if ((tmp2 != forbiddenExp) && (IS_NILLABLE(tmp2))) {
          if (remain != NULL)
              *remain = tmp2;
          else
              xmlExpFree(ctxt, tmp2);
          if (mult != NULL)
              *mult = tmp;
          else
              xmlExpFree(ctxt, tmp);
#ifdef DEBUG_DERIV
          printf("Divide succeeded %d\n", i);
#endif
          return(i);
      }
      xmlExpFree(ctxt, tmp);
      xmlExpFree(ctxt, tmp2);
    }
#ifdef DEBUG_DERIV
    printf("Divide failed\n");
#endif
    return(0);
}

/**
 * xmlExpExpDeriveInt:
 * @ctxt: the expressions context
 * @exp: the englobing expression
 * @sub: the subexpression
 *
 * Try to do a step of Brzozowski derivation but at a higher level
 * the input being a subexpression.
 *
 * Returns the resulting expression or NULL in case of internal error
 */
static xmlExpNodePtr
xmlExpExpDeriveInt(xmlExpCtxtPtr ctxt, xmlExpNodePtr exp, xmlExpNodePtr sub) {
    xmlExpNodePtr ret, tmp, tmp2, tmp3;
    const xmlChar **tab;
    int len, i;

    /*
     * In case of equality and if the expression can only consume a finite
     * amount, then the derivation is empty
     */
    if ((exp == sub) && (exp->c_max >= 0)) {
#ifdef DEBUG_DERIV
        printf("Equal(exp, sub) and finite -> Empty\n");
#endif
        return(emptyExp);
    }
    /*
     * decompose sub sequence first
     */
    if (sub->type == XML_EXP_EMPTY) {
#ifdef DEBUG_DERIV
        printf("Empty(sub) -> Empty\n");
#endif
      exp->ref++;
        return(exp);
    }
    if (sub->type == XML_EXP_SEQ) {
#ifdef DEBUG_DERIV
        printf("Seq(sub) -> decompose\n");
#endif
        tmp = xmlExpExpDeriveInt(ctxt, exp, sub->exp_left);
      if (tmp == NULL)
          return(NULL);
      if (tmp == forbiddenExp)
          return(tmp);
      ret = xmlExpExpDeriveInt(ctxt, tmp, sub->exp_right);
      xmlExpFree(ctxt, tmp);
      return(ret);
    }
    if (sub->type == XML_EXP_OR) {
#ifdef DEBUG_DERIV
        printf("Or(sub) -> decompose\n");
#endif
        tmp = xmlExpExpDeriveInt(ctxt, exp, sub->exp_left);
      if (tmp == forbiddenExp)
          return(tmp);
      if (tmp == NULL)
          return(NULL);
      ret = xmlExpExpDeriveInt(ctxt, exp, sub->exp_right);
      if ((ret == NULL) || (ret == forbiddenExp)) {
          xmlExpFree(ctxt, tmp);
          return(ret);
      }
      return(xmlExpHashGetEntry(ctxt, XML_EXP_OR, tmp, ret, NULL, 0, 0));
    }
    if (!xmlExpCheckCard(exp, sub)) {
#ifdef DEBUG_DERIV
        printf("CheckCard(exp, sub) failed -> Forbid\n");
#endif
        return(forbiddenExp);
    }
    switch (exp->type) {
        case XML_EXP_EMPTY:
          if (sub == emptyExp)
              return(emptyExp);
#ifdef DEBUG_DERIV
          printf("Empty(exp) -> Forbid\n");
#endif
          return(forbiddenExp);
        case XML_EXP_FORBID:
#ifdef DEBUG_DERIV
          printf("Forbid(exp) -> Forbid\n");
#endif
          return(forbiddenExp);
        case XML_EXP_ATOM:
          if (sub->type == XML_EXP_ATOM) {
              /* TODO: handle wildcards */
              if (exp->exp_str == sub->exp_str) {
#ifdef DEBUG_DERIV
                printf("Atom match -> Empty\n");
#endif
                return(emptyExp);
                }
#ifdef DEBUG_DERIV
            printf("Atom mismatch -> Forbid\n");
#endif
              return(forbiddenExp);
          }
          if ((sub->type == XML_EXP_COUNT) &&
              (sub->exp_max == 1) &&
              (sub->exp_left->type == XML_EXP_ATOM)) {
              /* TODO: handle wildcards */
              if (exp->exp_str == sub->exp_left->exp_str) {
#ifdef DEBUG_DERIV
                printf("Atom match -> Empty\n");
#endif
                return(emptyExp);
            }
#ifdef DEBUG_DERIV
            printf("Atom mismatch -> Forbid\n");
#endif
              return(forbiddenExp);
          }
#ifdef DEBUG_DERIV
          printf("Compex exp vs Atom -> Forbid\n");
#endif
          return(forbiddenExp);
        case XML_EXP_SEQ:
          /* try to get the sequence consumed only if possible */
          if (xmlExpCheckCard(exp->exp_left, sub)) {
            /* See if the sequence can be consumed directly */
#ifdef DEBUG_DERIV
            printf("Seq trying left only\n");
#endif
            ret = xmlExpExpDeriveInt(ctxt, exp->exp_left, sub);
            if ((ret != forbiddenExp) && (ret != NULL)) {
#ifdef DEBUG_DERIV
                printf("Seq trying left only worked\n");
#endif
                /*
                 * TODO: assumption here that we are determinist
                 *       i.e. we won't get to a nillable exp left
                 *       subset which could be matched by the right
                 *       part too.
                 * e.g.: (a | b)+,(a | c) and 'a+,a'
                 */
                exp->exp_right->ref++;
                return(xmlExpHashGetEntry(ctxt, XML_EXP_SEQ, ret,
                                    exp->exp_right, NULL, 0, 0));
            }
#ifdef DEBUG_DERIV
          } else {
            printf("Seq: left too short\n");
#endif
          }
          /* Try instead to decompose */
          if (sub->type == XML_EXP_COUNT) {
            int min, max;

#ifdef DEBUG_DERIV
            printf("Seq: sub is a count\n");
#endif
              ret = xmlExpExpDeriveInt(ctxt, exp->exp_left, sub->exp_left);
            if (ret == NULL)
                return(NULL);
            if (ret != forbiddenExp) {
#ifdef DEBUG_DERIV
                printf("Seq , Count match on left\n");
#endif
                if (sub->exp_max < 0)
                    max = -1;
                  else
                    max = sub->exp_max -1;
                if (sub->exp_min > 0)
                    min = sub->exp_min -1;
                else
                    min = 0;
                exp->exp_right->ref++;
                tmp = xmlExpHashGetEntry(ctxt, XML_EXP_SEQ, ret,
                                         exp->exp_right, NULL, 0, 0);
                if (tmp == NULL)
                    return(NULL);

                sub->exp_left->ref++;
                tmp2 = xmlExpHashGetEntry(ctxt, XML_EXP_COUNT,
                              sub->exp_left, NULL, NULL, min, max);
                if (tmp2 == NULL) {
                    xmlExpFree(ctxt, tmp);
                  return(NULL);
                }
                ret = xmlExpExpDeriveInt(ctxt, tmp, tmp2);
                xmlExpFree(ctxt, tmp);
                xmlExpFree(ctxt, tmp2);
                return(ret);
            }
          }
          /* we made no progress on structured operations */
          break;
        case XML_EXP_OR:
#ifdef DEBUG_DERIV
          printf("Or , trying both side\n");
#endif
          ret = xmlExpExpDeriveInt(ctxt, exp->exp_left, sub);
          if (ret == NULL)
              return(NULL);
          tmp = xmlExpExpDeriveInt(ctxt, exp->exp_right, sub);
          if (tmp == NULL) {
            xmlExpFree(ctxt, ret);
              return(NULL);
          }
          return(xmlExpHashGetEntry(ctxt, XML_EXP_OR, ret, tmp, NULL, 0, 0));
        case XML_EXP_COUNT: {
          int min, max;

          if (sub->type == XML_EXP_COUNT) {
              /*
             * Try to see if the loop is completely subsumed
             */
              tmp = xmlExpExpDeriveInt(ctxt, exp->exp_left, sub->exp_left);
            if (tmp == NULL)
                return(NULL);
            if (tmp == forbiddenExp) {
                int mult;

#ifdef DEBUG_DERIV
                printf("Count, Count inner don't subsume\n");
#endif
                mult = xmlExpDivide(ctxt, sub->exp_left, exp->exp_left,
                                    NULL, &tmp);
                if (mult <= 0) {
#ifdef DEBUG_DERIV
                  printf("Count, Count not multiple => forbidden\n");
#endif
                        return(forbiddenExp);
                }
                if (sub->exp_max == -1) {
                    max = -1;
                  if (exp->exp_max == -1) {
                      if (exp->exp_min <= sub->exp_min * mult)
                          min = 0;
                      else
                          min = exp->exp_min - sub->exp_min * mult;
                  } else {
#ifdef DEBUG_DERIV
                      printf("Count, Count finite can't subsume infinite\n");
#endif
                            xmlExpFree(ctxt, tmp);
                      return(forbiddenExp);
                  }
                } else {
                  if (exp->exp_max == -1) {
#ifdef DEBUG_DERIV
                      printf("Infinite loop consume mult finite loop\n");
#endif
                      if (exp->exp_min > sub->exp_min * mult) {
                        max = -1;
                        min = exp->exp_min - sub->exp_min * mult;
                      } else {
                        max = -1;
                        min = 0;
                      }
                  } else {
                      if (exp->exp_max < sub->exp_max * mult) {
#ifdef DEBUG_DERIV
                        printf("loops max mult mismatch => forbidden\n");
#endif
                        xmlExpFree(ctxt, tmp);
                        return(forbiddenExp);
                      }
                      if (sub->exp_max * mult > exp->exp_min)
                        min = 0;
                      else
                        min = exp->exp_min - sub->exp_max * mult;
                      max = exp->exp_max - sub->exp_max * mult;
                  }
                }
            } else if (!IS_NILLABLE(tmp)) {
                /*
                 * TODO: loop here to try to grow if working on finite
                 *       blocks.
                 */
#ifdef DEBUG_DERIV
                printf("Count, Count remain not nillable => forbidden\n");
#endif
                xmlExpFree(ctxt, tmp);
                return(forbiddenExp);
            } else if (sub->exp_max == -1) {
                if (exp->exp_max == -1) {
                    if (exp->exp_min <= sub->exp_min) {
#ifdef DEBUG_DERIV
                      printf("Infinite loops Okay => COUNT(0,Inf)\n");
#endif
                            max = -1;
                      min = 0;
                  } else {
#ifdef DEBUG_DERIV
                      printf("Infinite loops min => Count(X,Inf)\n");
#endif
                            max = -1;
                      min = exp->exp_min - sub->exp_min;
                  }
                } else if (exp->exp_min > sub->exp_min) {
#ifdef DEBUG_DERIV
                  printf("loops min mismatch 1 => forbidden ???\n");
#endif
                    xmlExpFree(ctxt, tmp);
                    return(forbiddenExp);
                } else {
                  max = -1;
                  min = 0;
                }
            } else {
                if (exp->exp_max == -1) {
#ifdef DEBUG_DERIV
                  printf("Infinite loop consume finite loop\n");
#endif
                    if (exp->exp_min > sub->exp_min) {
                      max = -1;
                      min = exp->exp_min - sub->exp_min;
                  } else {
                      max = -1;
                      min = 0;
                  }
                } else {
                    if (exp->exp_max < sub->exp_max) {
#ifdef DEBUG_DERIV
                      printf("loops max mismatch => forbidden\n");
#endif
                      xmlExpFree(ctxt, tmp);
                      return(forbiddenExp);
                  }
                  if (sub->exp_max > exp->exp_min)
                      min = 0;
                  else
                      min = exp->exp_min - sub->exp_max;
                  max = exp->exp_max - sub->exp_max;
                }
            }
#ifdef DEBUG_DERIV
            printf("loops match => SEQ(COUNT())\n");
#endif
            exp->exp_left->ref++;
            tmp2 = xmlExpHashGetEntry(ctxt, XML_EXP_COUNT, exp->exp_left,
                                      NULL, NULL, min, max);
            if (tmp2 == NULL) {
                return(NULL);
            }
                ret = xmlExpHashGetEntry(ctxt, XML_EXP_SEQ, tmp, tmp2,
                                     NULL, 0, 0);
            return(ret);
          }
          tmp = xmlExpExpDeriveInt(ctxt, exp->exp_left, sub);
          if (tmp == NULL)
            return(NULL);
          if (tmp == forbiddenExp) {
#ifdef DEBUG_DERIV
            printf("loop mismatch => forbidden\n");
#endif
            return(forbiddenExp);
          }
          if (exp->exp_min > 0)
            min = exp->exp_min - 1;
          else
            min = 0;
          if (exp->exp_max < 0)
            max = -1;
          else
            max = exp->exp_max - 1;

#ifdef DEBUG_DERIV
          printf("loop match => SEQ(COUNT())\n");
#endif
          exp->exp_left->ref++;
          tmp2 = xmlExpHashGetEntry(ctxt, XML_EXP_COUNT, exp->exp_left,
                              NULL, NULL, min, max);
          if (tmp2 == NULL)
            return(NULL);
          ret = xmlExpHashGetEntry(ctxt, XML_EXP_SEQ, tmp, tmp2,
                             NULL, 0, 0);
          return(ret);
      }
    }

#ifdef DEBUG_DERIV
    printf("Fallback to derivative\n");
#endif
    if (IS_NILLABLE(sub)) {
        if (!(IS_NILLABLE(exp)))
          return(forbiddenExp);
      else
          ret = emptyExp;
    } else
      ret = NULL;
    /*
     * here the structured derivation made no progress so
     * we use the default token based derivation to force one more step
     */
    if (ctxt->tabSize == 0)
        ctxt->tabSize = 40;

    tab = (const xmlChar **) xmlMalloc(ctxt->tabSize *
                                     sizeof(const xmlChar *));
    if (tab == NULL) {
      return(NULL);
    }

    /*
     * collect all the strings accepted by the subexpression on input
     */
    len = xmlExpGetStartInt(ctxt, sub, tab, ctxt->tabSize, 0);
    while (len < 0) {
        const xmlChar **temp;
      temp = (const xmlChar **) xmlRealloc((xmlChar **) tab, ctxt->tabSize * 2 *
                                           sizeof(const xmlChar *));
      if (temp == NULL) {
          xmlFree((xmlChar **) tab);
          return(NULL);
      }
      tab = temp;
      ctxt->tabSize *= 2;
      len = xmlExpGetStartInt(ctxt, sub, tab, ctxt->tabSize, 0);
    }
    for (i = 0;i < len;i++) {
        tmp = xmlExpStringDeriveInt(ctxt, exp, tab[i]);
      if ((tmp == NULL) || (tmp == forbiddenExp)) {
          xmlExpFree(ctxt, ret);
          xmlFree((xmlChar **) tab);
          return(tmp);
      }
      tmp2 = xmlExpStringDeriveInt(ctxt, sub, tab[i]);
      if ((tmp2 == NULL) || (tmp2 == forbiddenExp)) {
          xmlExpFree(ctxt, tmp);
          xmlExpFree(ctxt, ret);
          xmlFree((xmlChar **) tab);
          return(tmp);
      }
      tmp3 = xmlExpExpDeriveInt(ctxt, tmp, tmp2);
      xmlExpFree(ctxt, tmp);
      xmlExpFree(ctxt, tmp2);

      if ((tmp3 == NULL) || (tmp3 == forbiddenExp)) {
          xmlExpFree(ctxt, ret);
          xmlFree((xmlChar **) tab);
          return(tmp3);
      }

      if (ret == NULL)
          ret = tmp3;
      else {
          ret = xmlExpHashGetEntry(ctxt, XML_EXP_OR, ret, tmp3, NULL, 0, 0);
          if (ret == NULL) {
            xmlFree((xmlChar **) tab);
              return(NULL);
          }
      }
    }
    xmlFree((xmlChar **) tab);
    return(ret);
}
    
/**
 * xmlExpExpDerive:
 * @ctxt: the expressions context
 * @exp: the englobing expression
 * @sub: the subexpression
 *
 * Evaluates the expression resulting from @exp consuming a sub expression @sub
 * Based on algebraic derivation and sometimes direct Brzozowski derivation
 * it usually tatkes less than linear time and can handle expressions generating
 * infinite languages.
 *
 * Returns the resulting expression or NULL in case of internal error, the
 *         result must be freed
 */
xmlExpNodePtr
xmlExpExpDerive(xmlExpCtxtPtr ctxt, xmlExpNodePtr exp, xmlExpNodePtr sub) {
    if ((exp == NULL) || (ctxt == NULL) || (sub == NULL))
        return(NULL);

    /*
     * O(1) speedups
     */
    if (IS_NILLABLE(sub) && (!IS_NILLABLE(exp))) {
#ifdef DEBUG_DERIV
      printf("Sub nillable and not exp : can't subsume\n");
#endif
        return(forbiddenExp);
    }
    if (xmlExpCheckCard(exp, sub) == 0) {
#ifdef DEBUG_DERIV
      printf("sub generate longuer sequances than exp : can't subsume\n");
#endif
        return(forbiddenExp);
    }
    return(xmlExpExpDeriveInt(ctxt, exp, sub));
}

/**
 * xmlExpSubsume:
 * @ctxt: the expressions context
 * @exp: the englobing expression
 * @sub: the subexpression
 *
 * Check whether @exp accepts all the languages accexpted by @sub
 * the input being a subexpression.
 *
 * Returns 1 if true 0 if false and -1 in case of failure.
 */
int
xmlExpSubsume(xmlExpCtxtPtr ctxt, xmlExpNodePtr exp, xmlExpNodePtr sub) {
    xmlExpNodePtr tmp;
    
    if ((exp == NULL) || (ctxt == NULL) || (sub == NULL))
        return(-1);

    /*
     * TODO: speedup by checking the language of sub is a subset of the
     *       language of exp
     */
    /*
     * O(1) speedups
     */
    if (IS_NILLABLE(sub) && (!IS_NILLABLE(exp))) {
#ifdef DEBUG_DERIV
      printf("Sub nillable and not exp : can't subsume\n");
#endif
        return(0);
    }
    if (xmlExpCheckCard(exp, sub) == 0) {
#ifdef DEBUG_DERIV
      printf("sub generate longuer sequances than exp : can't subsume\n");
#endif
        return(0);
    }
    tmp = xmlExpExpDeriveInt(ctxt, exp, sub);
#ifdef DEBUG_DERIV
    printf("Result derivation :\n");
    PRINT_EXP(tmp);
#endif
    if (tmp == NULL)
        return(-1);
    if (tmp == forbiddenExp)
      return(0);
    if (tmp == emptyExp)
      return(1);
    if ((tmp != NULL) && (IS_NILLABLE(tmp))) {
        xmlExpFree(ctxt, tmp);
        return(1);
    }
    xmlExpFree(ctxt, tmp);
    return(0);
}

/************************************************************************
 *                                                    *
 *                Parsing expression                        *
 *                                                    *
 ************************************************************************/

static xmlExpNodePtr xmlExpParseExpr(xmlExpCtxtPtr ctxt);

#undef CUR
#define CUR (*ctxt->cur)
#undef NEXT
#define NEXT ctxt->cur++;
#undef IS_BLANK
#define IS_BLANK(c) ((c == ' ') || (c == '\n') || (c == '\r') || (c == '\t'))
#define SKIP_BLANKS while (IS_BLANK(*ctxt->cur)) ctxt->cur++;

static int
xmlExpParseNumber(xmlExpCtxtPtr ctxt) {
    int ret = 0;

    SKIP_BLANKS
    if (CUR == '*') {
      NEXT
      return(-1);
    }
    if ((CUR < '0') || (CUR > '9'))
        return(-1);
    while ((CUR >= '0') && (CUR <= '9')) {
        ret = ret * 10 + (CUR - '0');
      NEXT
    }
    return(ret);
}

static xmlExpNodePtr
xmlExpParseOr(xmlExpCtxtPtr ctxt) {
    const char *base;
    xmlExpNodePtr ret;
    const xmlChar *val;

    SKIP_BLANKS
    base = ctxt->cur;
    if (*ctxt->cur == '(') {
        NEXT
      ret = xmlExpParseExpr(ctxt);
      SKIP_BLANKS
      if (*ctxt->cur != ')') {
          fprintf(stderr, "unbalanced '(' : %s\n", base);
          xmlExpFree(ctxt, ret);
          return(NULL);
      }
      NEXT;
      SKIP_BLANKS
      goto parse_quantifier;
    }
    while ((CUR != 0) && (!(IS_BLANK(CUR))) && (CUR != '(') &&
           (CUR != ')') && (CUR != '|') && (CUR != ',') && (CUR != '{') &&
         (CUR != '*') && (CUR != '+') && (CUR != '?') && (CUR != '}'))
      NEXT;
    val = xmlDictLookup(ctxt->dict, BAD_CAST base, ctxt->cur - base);
    if (val == NULL)
        return(NULL);
    ret = xmlExpHashGetEntry(ctxt, XML_EXP_ATOM, NULL, NULL, val, 0, 0);
    if (ret == NULL)
        return(NULL);
    SKIP_BLANKS
parse_quantifier:
    if (CUR == '{') {
        int min, max;

        NEXT
      min = xmlExpParseNumber(ctxt);
      if (min < 0) {
          xmlExpFree(ctxt, ret);
          return(NULL);
      }
      SKIP_BLANKS
      if (CUR == ',') {
          NEXT
          max = xmlExpParseNumber(ctxt);
          SKIP_BLANKS
      } else
          max = min;
      if (CUR != '}') {
          xmlExpFree(ctxt, ret);
          return(NULL);
      }
        NEXT
      ret = xmlExpHashGetEntry(ctxt, XML_EXP_COUNT, ret, NULL, NULL,
                               min, max);
      SKIP_BLANKS
    } else if (CUR == '?') {
        NEXT
      ret = xmlExpHashGetEntry(ctxt, XML_EXP_COUNT, ret, NULL, NULL,
                               0, 1);
      SKIP_BLANKS
    } else if (CUR == '+') {
        NEXT
      ret = xmlExpHashGetEntry(ctxt, XML_EXP_COUNT, ret, NULL, NULL,
                               1, -1);
      SKIP_BLANKS
    } else if (CUR == '*') {
        NEXT
      ret = xmlExpHashGetEntry(ctxt, XML_EXP_COUNT, ret, NULL, NULL,
                               0, -1);
      SKIP_BLANKS
    } 
    return(ret);
}


static xmlExpNodePtr
xmlExpParseSeq(xmlExpCtxtPtr ctxt) {
    xmlExpNodePtr ret, right;

    ret = xmlExpParseOr(ctxt);
    SKIP_BLANKS
    while (CUR == '|') {
        NEXT
      right = xmlExpParseOr(ctxt);
      if (right == NULL) {
          xmlExpFree(ctxt, ret);
          return(NULL);
      }
      ret = xmlExpHashGetEntry(ctxt, XML_EXP_OR, ret, right, NULL, 0, 0);
      if (ret == NULL)
          return(NULL);
    }
    return(ret);
}

static xmlExpNodePtr
xmlExpParseExpr(xmlExpCtxtPtr ctxt) {
    xmlExpNodePtr ret, right;

    ret = xmlExpParseSeq(ctxt);
    SKIP_BLANKS
    while (CUR == ',') {
        NEXT
      right = xmlExpParseSeq(ctxt);
      if (right == NULL) {
          xmlExpFree(ctxt, ret);
          return(NULL);
      }
      ret = xmlExpHashGetEntry(ctxt, XML_EXP_SEQ, ret, right, NULL, 0, 0);
      if (ret == NULL)
          return(NULL);
    }
    return(ret);
}

/**
 * xmlExpParse:
 * @ctxt: the expressions context
 * @expr: the 0 terminated string
 *
 * Minimal parser for regexps, it understand the following constructs
 *  - string terminals
 *  - choice operator |
 *  - sequence operator ,
 *  - subexpressions (...)
 *  - usual cardinality operators + * and ?
 *  - finite sequences  { min, max }
 *  - infinite sequences { min, * }
 * There is minimal checkings made especially no checking on strings values
 *
 * Returns a new expression or NULL in case of failure
 */
xmlExpNodePtr
xmlExpParse(xmlExpCtxtPtr ctxt, const char *expr) {
    xmlExpNodePtr ret;

    ctxt->expr = expr;
    ctxt->cur = expr;

    ret = xmlExpParseExpr(ctxt);
    SKIP_BLANKS
    if (*ctxt->cur != 0) {
        xmlExpFree(ctxt, ret);
        return(NULL);
    }
    return(ret);
}

static void
xmlExpDumpInt(xmlBufferPtr buf, xmlExpNodePtr expr, int glob) {
    xmlExpNodePtr c;

    if (expr == NULL) return;
    if (glob) xmlBufferWriteChar(buf, "(");
    switch (expr->type) {
        case XML_EXP_EMPTY:
          xmlBufferWriteChar(buf, "empty");
          break;
        case XML_EXP_FORBID:
          xmlBufferWriteChar(buf, "forbidden");
          break;
        case XML_EXP_ATOM:
          xmlBufferWriteCHAR(buf, expr->exp_str);
          break;
        case XML_EXP_SEQ:
          c = expr->exp_left;
          if ((c->type == XML_EXP_SEQ) || (c->type == XML_EXP_OR))
              xmlExpDumpInt(buf, c, 1);
          else
              xmlExpDumpInt(buf, c, 0);
          xmlBufferWriteChar(buf, " , ");
          c = expr->exp_right;
          if ((c->type == XML_EXP_SEQ) || (c->type == XML_EXP_OR))
              xmlExpDumpInt(buf, c, 1);
          else
              xmlExpDumpInt(buf, c, 0);
            break;
        case XML_EXP_OR:
          c = expr->exp_left;
          if ((c->type == XML_EXP_SEQ) || (c->type == XML_EXP_OR))
              xmlExpDumpInt(buf, c, 1);
          else
              xmlExpDumpInt(buf, c, 0);
          xmlBufferWriteChar(buf, " | ");
          c = expr->exp_right;
          if ((c->type == XML_EXP_SEQ) || (c->type == XML_EXP_OR))
              xmlExpDumpInt(buf, c, 1);
          else
              xmlExpDumpInt(buf, c, 0);
            break;
        case XML_EXP_COUNT: {
          char rep[40];
          
          c = expr->exp_left;
          if ((c->type == XML_EXP_SEQ) || (c->type == XML_EXP_OR))
              xmlExpDumpInt(buf, c, 1);
          else
              xmlExpDumpInt(buf, c, 0);
          if ((expr->exp_min == 0) && (expr->exp_max == 1)) {
            rep[0] = '?';
            rep[1] = 0;
          } else if ((expr->exp_min == 0) && (expr->exp_max == -1)) {
            rep[0] = '*';
            rep[1] = 0;
          } else if ((expr->exp_min == 1) && (expr->exp_max == -1)) {
            rep[0] = '+';
            rep[1] = 0;
          } else if (expr->exp_max == expr->exp_min) {
              snprintf(rep, 39, "{%d}", expr->exp_min);
          } else if (expr->exp_max < 0) {
              snprintf(rep, 39, "{%d,inf}", expr->exp_min);
          } else {
              snprintf(rep, 39, "{%d,%d}", expr->exp_min, expr->exp_max);
          }
          rep[39] = 0;
          xmlBufferWriteChar(buf, rep);
          break;
      }
      default:
          fprintf(stderr, "Error in tree\n");
    }
    if (glob)
        xmlBufferWriteChar(buf, ")");
}
/**
 * xmlExpDump:
 * @buf:  a buffer to receive the output
 * @expr:  the compiled expression
 *
 * Serialize the expression as compiled to the buffer
 */
void
xmlExpDump(xmlBufferPtr buf, xmlExpNodePtr expr) {
    if ((buf == NULL) || (expr == NULL))
        return;
    xmlExpDumpInt(buf, expr, 0);
}

/**
 * xmlExpMaxToken:
 * @expr: a compiled expression
 *
 * Indicate the maximum number of input a expression can accept
 *
 * Returns the maximum length or -1 in case of error
 */
int
xmlExpMaxToken(xmlExpNodePtr expr) {
    if (expr == NULL)
        return(-1);
    return(expr->c_max);
}

/**
 * xmlExpCtxtNbNodes:
 * @ctxt: an expression context
 *
 * Debugging facility provides the number of allocated nodes at a that point
 *
 * Returns the number of nodes in use or -1 in case of error
 */
int
xmlExpCtxtNbNodes(xmlExpCtxtPtr ctxt) {
    if (ctxt == NULL)
        return(-1);
    return(ctxt->nb_nodes);
}

/**
 * xmlExpCtxtNbCons:
 * @ctxt: an expression context
 *
 * Debugging facility provides the number of allocated nodes over lifetime
 *
 * Returns the number of nodes ever allocated or -1 in case of error
 */
int
xmlExpCtxtNbCons(xmlExpCtxtPtr ctxt) {
    if (ctxt == NULL)
        return(-1);
    return(ctxt->nb_cons);
}

#endif /* LIBXML_EXPR_ENABLED */
#define bottom_xmlregexp
#include "elfgcchack.h"
#endif /* LIBXML_REGEXP_ENABLED */

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