/*
 * 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 thise includes:
 *    - 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

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

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

#define ERROR(str) ctxt->error = 1;					\
    xmlGenericError(xmlGenericErrorContext, "Regexp: %s: %s\n", str, ctxt->cur)
#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;

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


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

typedef enum {
    XML_REGEXP_EPSILON = 1,
    XML_REGEXP_CHARVAL,
    XML_REGEXP_RANGES,
    XML_REGEXP_SUBREG,
    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,
    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
} 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;
    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;
    int neg;
    int codepoint;
    xmlRegStatePtr start;
    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;
};

struct _xmlAutomataState {
    xmlRegStateType type;
    xmlRegMarkedType mark;
    int no;

    int maxTrans;
    int nbTrans;
    xmlRegTrans *trans;
};

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;
};

struct _xmlRegexp {
    xmlChar *string;
    int nbStates;
    xmlRegStatePtr *states;
    int nbAtoms;
    xmlRegAtomPtr *atoms;
    int nbCounters;
    xmlRegCounter *counters;
    int determinist;
};

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 automate 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 found an inderterministic 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 char 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 */

};

#define REGEXP_ALL_COUNTER	0x123456
#define REGEXP_ALL_LAX_COUNTER	0x123457

static void xmlFAParseRegExp(xmlRegParserCtxtPtr ctxt, int top);

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

/**
 * xmlRegEpxFromParse:
 * @ctxt:  the parser context used to build it
 *
 * Allocate a new regexp and fill it with the reult 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)
	return(NULL);
    memset(ret, 0, sizeof(xmlRegexp));
    ret->string = ctxt->string;
    ctxt->string = NULL;
    ret->nbStates = ctxt->nbStates;
    ctxt->nbStates = 0;
    ret->states = ctxt->states;
    ctxt->states = NULL;
    ret->nbAtoms = ctxt->nbAtoms;
    ctxt->nbAtoms = 0;
    ret->atoms = ctxt->atoms;
    ctxt->atoms = NULL;
    ret->nbCounters = ctxt->nbCounters;
    ctxt->nbCounters = 0;
    ret->counters = ctxt->counters;
    ctxt->counters = NULL;
    ret->determinist = ctxt->determinist;
    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->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) {
	ERROR("failed to allocate regexp 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);
}

/**
 * xmlRegNewAtom:
 * @ctxt:  the regexp parser context
 * @type:  the type of atom
 *
 * Allocate a new regexp range
 *
 * 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) {
	ERROR("failed to allocate regexp 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)
	xmlFree(atom->valuep);
    xmlFree(atom);
}

static xmlRegStatePtr
xmlRegNewState(xmlRegParserCtxtPtr ctxt) {
    xmlRegStatePtr ret;

    ret = (xmlRegStatePtr) xmlMalloc(sizeof(xmlRegState));
    if (ret == NULL) {
	ERROR("failed to allocate regexp 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);
    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;
    }
    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->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]));
    }
}

#if 0
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) {
	    ERROR("add range: allocation failed");
	    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) {
	    ERROR("add range: allocation failed");
	    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) {
	    ERROR("reg counter: allocation failed");
	    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) {
	    ERROR("reg counter: allocation failed");
	    ctxt->maxCounters /= 2;
	    return(-1);
	}
	ctxt->counters = tmp;
    }
    ctxt->counters[ctxt->nbCounters].min = -1;
    ctxt->counters[ctxt->nbCounters].max = -1;
    return(ctxt->nbCounters++);
}

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

static void 
xmlRegStateAddTrans(xmlRegParserCtxtPtr ctxt, xmlRegStatePtr state,
	            xmlRegAtomPtr atom, xmlRegStatePtr target,
		    int counter, int count) {
    if (state == NULL) {
	ERROR("add state: state is NULL");
	return;
    }
    if (target == NULL) {
	ERROR("add state: target is NULL");
	return;
    }
    if (state->maxTrans == 0) {
	state->maxTrans = 4;
	state->trans = (xmlRegTrans *) xmlMalloc(state->maxTrans *
		                             sizeof(xmlRegTrans));
	if (state->trans == NULL) {
	    ERROR("add range: allocation failed");
	    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) {
	    ERROR("add range: allocation failed");
	    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");
    else (count >= 0)
	printf("count based %d", count);
    else if (counter >= 0)
	printf("counted %d", counter);
    else if (atom == NULL)
	printf("epsilon transition");
    printf("\n");
#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->nbTrans++;
}

static void 
xmlRegStatePush(xmlRegParserCtxtPtr ctxt, xmlRegStatePtr state) {
    if (ctxt->maxStates == 0) {
	ctxt->maxStates = 4;
	ctxt->states = (xmlRegStatePtr *) xmlMalloc(ctxt->maxStates *
		                             sizeof(xmlRegStatePtr));
	if (ctxt->states == NULL) {
	    ERROR("add range: allocation failed");
	    ctxt->maxStates = 0;
	    return;
	}
    } else if (ctxt->nbStates >= ctxt->maxStates) {
	xmlRegStatePtr *tmp;
	ctxt->maxStates *= 2;
	tmp = (xmlRegStatePtr *) xmlRealloc(ctxt->states, ctxt->maxStates *
		                             sizeof(xmlRegStatePtr));
	if (tmp == NULL) {
	    ERROR("add range: allocation failed");
	    ctxt->maxStates /= 2;
	    return;
	}
	ctxt->states = tmp;
    }
    state->no = ctxt->nbStates;
    ctxt->states[ctxt->nbStates++] = state;
}

/**
 * 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
 *
 */
static void
xmlFAGenerateTransitions(xmlRegParserCtxtPtr ctxt, xmlRegStatePtr from,
	                 xmlRegStatePtr to, xmlRegAtomPtr atom) {
    if (atom == NULL) {
	ERROR("genrate transition: atom == NULL");
	return;
    }
    if (atom->type == XML_REGEXP_SUBREG) {
	/*
	 * this is a subexpression handling one should not need to
	 * create a new node excep for XML_REGEXP_QUANT_RANGE.
	 */
	xmlRegAtomPush(ctxt, atom);
	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);
	}
	switch (atom->quant) {
	    case XML_REGEXP_QUANT_OPT:
		atom->quant = XML_REGEXP_QUANT_ONCE;
		xmlFAGenerateEpsilonTransition(ctxt, atom->start, atom->stop);
		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 newstate;

		/*
		 * This one is nasty:
		 *   1/ register a new counter
		 *   2/ register an epsilon transition associated to
		 *      this counter going from atom->stop to atom->start
		 *   3/ create a new state
		 *   4/ generate a counted transition from atom->stop to
		 *      that state
		 */
		counter = xmlRegGetCounter(ctxt);
		ctxt->counters[counter].min = atom->min - 1;
		ctxt->counters[counter].max = atom->max - 1;
		atom->min = 0;
		atom->max = 0;
		atom->quant = XML_REGEXP_QUANT_ONCE;
		xmlFAGenerateCountedEpsilonTransition(ctxt, atom->stop,
			                              atom->start, counter);
		if (to != NULL) {
		    newstate = to;
		} else {
		    newstate = xmlRegNewState(ctxt);
		    xmlRegStatePush(ctxt, newstate);
		    ctxt->state = newstate;
		}
		xmlFAGenerateCountedTransition(ctxt, atom->stop,
			                       newstate, counter);
	    }
	    default:
		break;
	}
	return;
    } else {
	if (to == NULL) {
	    to = xmlRegNewState(ctxt);
	    xmlRegStatePush(ctxt, to);
	}
	xmlRegStateAddTrans(ctxt, from, atom, to, -1, -1);
	xmlRegAtomPush(ctxt, atom);
	ctxt->state = to;
    }
    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;
	default:
	    break;
    }
}

/**
 * xmlFAReduceEpsilonTransitions:
 * @ctxt:  a regexp parser context
 * @fromnr:  the from state
 * @tonr:  the to state 
 * @cpunter:  should that transition be associted 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].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;
}

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

    /*
     * build the completed transitions bypassing the epsilons
     * Use a marking algorithm to avoid loops
     */
    for (statenr = 0;statenr < ctxt->nbStates;statenr++) {
	state = ctxt->states[statenr];
	if (state == NULL)
	    continue;
	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
		    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
     */
    for (statenr = 0;statenr < ctxt->nbStates;statenr++) {
	state = ctxt->states[statenr];
	if (state == NULL)
	    continue;
	for (transnr = 0;transnr < state->nbTrans;transnr++) {
	    if ((state->trans[transnr].atom == NULL) &&
		(state->trans[transnr].count < 0) &&
		(state->trans[transnr].to >= 0)) {
		state->trans[transnr].to = -1;
	    }
	}
    }
}

/**
 * xmlFACompareAtoms:
 * @atom1:  an atom
 * @atom2:  an atom
 *
 * Compares two atoms to check whether they are equivatents
 *
 * Returns 1 if yes and 0 otherwise
 */
static int
xmlFACompareAtoms(xmlRegAtomPtr atom1, xmlRegAtomPtr atom2) {
    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_STRING:
	    return(xmlStrEqual((xmlChar *)atom1->valuep,
			       (xmlChar *)atom2->valuep));
        case XML_REGEXP_EPSILON:
	    return(1);
        case XML_REGEXP_CHARVAL:
	    return(atom1->codepoint == atom2->codepoint);
        case XML_REGEXP_RANGES:
	    TODO;
	    return(0);
	default:
	    break;
    }
    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 transnr;
    xmlRegTransPtr t1;

    if (state == NULL)
	return(ret);
    for (transnr = 0;transnr < state->nbTrans;transnr++) {
	t1 = &(state->trans[transnr]);
	/*
	 * check transitions conflicting with the one looked at
	 */
	if (t1->atom == NULL) {
	    if (t1->to == -1)
		continue;
	    ret = xmlFARecurseDeterminism(ctxt, ctxt->states[t1->to],
		                           to, atom);
	    if (ret == 0)
		return(0);
	    continue;
	}
	if (t1->to != to)
	    continue;
	if (xmlFACompareAtoms(t1->atom, atom))
	    return(0);
    }
    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;
    int i;
    int ret = 1;

    if (ctxt->determinist != -1)
	return(ctxt->determinist);

    /*
     * Check for all states that there isn'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;
	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) {
		    if (t1->to == t2->to) {
			if (xmlFACompareAtoms(t1->atom, t2->atom))
			    t2->to = -1; /* eliminate */
		    } else {
			/* not determinist ! */
			if (xmlFACompareAtoms(t1->atom, t2->atom))
			    ret = 0;
		    }
		} 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);
		    if (ret == 0)
			return(0);
		}
	    }
	    if (ret == 0)
		break;
	}
	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 = (xmlIsLetter(codepoint) || 
		   (codepoint == '_') || (codepoint == ':'));
	    break;
        case XML_REGEXP_NOTNAMECHAR:
	    neg = !neg;
        case XML_REGEXP_NAMECHAR:
	    ret = (xmlIsLetter(codepoint) || xmlIsDigit(codepoint) ||
		   (codepoint == '.') || (codepoint == '-') ||
		   (codepoint == '_') || (codepoint == ':') ||
		   xmlIsCombining(codepoint) || xmlIsExtender(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) || (!xmlIsChar(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) {
		    ret = xmlRegCheckCharacterRange(range->type, codepoint,
						0, range->start, range->end,
						range->blockName);
		    if (ret != 0)
			return(0); /* excluded char */
		} 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 an 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 ", exec->inputStack[exec->inputStackNr - (i + 1)]);
    } 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

    if (exec->maxRollbacks == 0) {
	exec->maxRollbacks = 4;
	exec->rollbacks = (xmlRegExecRollback *) xmlMalloc(exec->maxRollbacks *
		                             sizeof(xmlRegExecRollback));
	if (exec->rollbacks == NULL) {
	    fprintf(stderr, "exec save: allocation failed");
	    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) {
	    fprintf(stderr, "exec save: allocation failed");
	    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) {
		fprintf(stderr, "exec save: allocation failed");
		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
}

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

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

    exec->inputString = content;
    exec->index = 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;
    if (comp->nbCounters > 0) {
	exec->counts = (int *) xmlMalloc(comp->nbCounters * sizeof(int));
	if (exec->counts == NULL)
	    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;

	/*
	 * 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 = 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);
		}
		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 = 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;
    }
    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)
	return(0);
    return(exec->status);
}

/************************************************************************
 * 									*
 *	Progressive interface to the verifyer one atom at a time	*
 * 									*
 ************************************************************************/

/**
 * xmlRegExecCtxtPtr:
 * @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.
 */
xmlRegExecCtxtPtr
xmlRegNewExecCtxt(xmlRegexpPtr comp, xmlRegExecCallbacks callback, void *data) {
    xmlRegExecCtxtPtr exec;

    if (comp == NULL)
	return(NULL);
    exec = (xmlRegExecCtxtPtr) xmlMalloc(sizeof(xmlRegExecCtxt));
    if (exec == NULL) {
	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;
    exec->state = comp->states[0];
    exec->transno = 0;
    exec->transcount = 0;
    exec->callback = callback;
    exec->data = data;
    if (comp->nbCounters > 0) {
	exec->counts = (int *) xmlMalloc(comp->nbCounters * sizeof(int));
	if (exec->counts == NULL) {
	    xmlFree(exec);
	    return(NULL);
	}
        memset(exec->counts, 0, comp->nbCounters * sizeof(int));
    } else
	exec->counts = NULL;
    exec->inputStackMax = 0;
    exec->inputStackNr = 0;
    exec->inputStack = NULL;
    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++)
	    xmlFree(exec->inputStack[i].value);
	xmlFree(exec->inputStack);
    }
    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) {
	    fprintf(stderr, "push input: allocation failed");
	    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) {
	    fprintf(stderr, "push input: allocation failed");
	    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;
}


/**
 * xmlRegExecPushString:
 * @exec: a regexp execution context
 * @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) {
    xmlRegTransPtr trans;
    xmlRegAtomPtr atom;
    int ret;
    int final = 0;

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

    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) &&
			    (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 = xmlStrEqual(value, atom->valuep);
		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)) {
		    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]++;
		}
#ifdef DEBUG_PUSH
		printf("entering state %d\n", trans->to);
#endif
		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:
	    /*
	     * 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
	    }
	}
progress:
	continue;
    }
    if (exec->status == 0) {
        return(exec->state->type == XML_REGEXP_FINAL_STATE);
    }
    return(exec->status);
}

#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);
		}
		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 Shemas 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 = 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)
		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);
	}
    }
}

/**
 * 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'))) {
		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;
    int start = -1;
    int end = -1;

    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;
    } else if ((cur != 0x5B) && (cur != 0x5D)) {
	end = start = cur;
    } else {
	ERROR("Expecting a char range");
	return;
    }
    NEXT;
    if (start == '-') {
	return;
    }
    cur = CUR;
    if (cur != '-') {
        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;
	}
    } else if ((cur != 0x5B) && (cur != 0x5D)) {
	end = cur;
    } else {
	ERROR("Expecting the end of a char range");
	return;
    }
    NEXT;
    /* 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 == '\\') || (CUR == '.')) {
	    xmlFAParseCharClassEsc(ctxt);
	} else {
	    xmlFAParseCharRange(ctxt);
	}
    } while ((CUR != ']') && (CUR != '^') && (CUR != '-') &&
	     (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 == '-') {
	    NEXT;
	    ctxt->neg = !ctxt->neg;
	    if (CUR != '[') {
		ERROR("charClassExpr: '[' expected");
		break;
	    }
	    NEXT;
	    xmlFAParseCharGroup(ctxt);
	    if (CUR == ']') {
		NEXT;
	    } else {
		ERROR("charClassExpr: ']' expected");
		break;
	    }
	    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]+
 */
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;
	    cur = xmlFAParseQuantExact(ctxt);
	    if (cur >= 0)
		max = cur;
	}
	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;

	NEXT;
	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->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
 * @first:  is taht the first
 *
 * [2]   branch   ::=   piece*
 */
static void
xmlFAParseBranch(xmlRegParserCtxtPtr ctxt, int first) {
    xmlRegStatePtr previous;
    xmlRegAtomPtr prevatom = NULL;
    int ret;

    previous = ctxt->state;
    ret = xmlFAParsePiece(ctxt);
    if (ret != 0) {
	if (first) {
	    xmlFAGenerateTransitions(ctxt, previous, NULL, ctxt->atom);
	    previous = ctxt->state;
	} else {
	    prevatom = ctxt->atom;
	}
	ctxt->atom = NULL;
    }
    while ((ret != 0) && (ctxt->error == 0)) {
	ret = xmlFAParsePiece(ctxt);
	if (ret != 0) {
	    if (first) {
		xmlFAGenerateTransitions(ctxt, previous, NULL, ctxt->atom);
	    } else {
		xmlFAGenerateTransitions(ctxt, previous, NULL, prevatom);
		prevatom = ctxt->atom;
	    }
	    previous = ctxt->state;
	    ctxt->atom = NULL;
	}
    }
    if (!first) {
	xmlFAGenerateTransitions(ctxt, previous, ctxt->end, prevatom);
    }
}

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

    oldend = ctxt->end;

    start = ctxt->state;
    xmlFAParseBranch(ctxt, (ctxt->end == NULL));
    if (CUR != '|') {
	ctxt->end = ctxt->state;
	return;
    }
    end = ctxt->state;
    while ((CUR == '|') && (ctxt->error == 0)) {
	NEXT;
	ctxt->state = start;
	ctxt->end = end;
	xmlFAParseBranch(ctxt, 0);
    }
    if (!top)
	ctxt->end = oldend;
}

/************************************************************************
 * 									*
 * 			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;

    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 build 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");
    }
    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 generate the value
 *
 * Returns 1 if it matches, 0 if not and a negativa value in case of error
 */
int
xmlRegexpExec(xmlRegexpPtr comp, const xmlChar *content) {
    if ((comp == NULL) || (content == NULL))
	return(-1);
    return(xmlFARegExec(comp, content));
}

/**
 * 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);
    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);
    xmlRegStatePush(ctxt, ctxt->start);

    return(ctxt);
}

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

/**
 * xmlAutomataGetInitState:
 * @am: an automata
 *
 * 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 create 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);
    atom->data = data;
    if (atom == NULL)
	return(NULL);
    atom->valuep = xmlStrdup(token);

    xmlFAGenerateTransitions(am, from, to, atom);
    if (to == NULL)
	return(am->state);
    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
 * @min:  the maximum successive occurences of token
 *
 * If @to is NULL, this create 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;

    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;

    xmlFAGenerateTransitions(am, from, to, atom);
    if (to == NULL)
	to = am->state;
    if (to == NULL)
	return(NULL);
    if (min == 0)
	xmlFAGenerateEpsilonTransition(am, from, 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
 * @min:  the maximum successive occurences of token
 *
 * If @to is NULL, this create 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 transistion 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;
    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 = 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;
    if (to == NULL)
	to = am->state;
    if (to == NULL)
	return(NULL);
    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);
}

/**
 * xmlAutomataNewTransition:
 * @am: an automata
 * @from: the starting point of the transition
 * @to: the target point of the transition or NULL
 *
 * If @to is NULL, this create first a new target state in the automata
 * and then adds a 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
 *
 * If @to is NULL, this create 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 create 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 create 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;

    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 */
#endif /* LIBXML_REGEXP_ENABLED */