xmlregexp.c

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

#define IN_LIBXML
#include "libxml.h"

#ifdef LIBXML_REGEXP_ENABLED

/* #define DEBUG_ERR */

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

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

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

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

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

#define CUR_SCHAR(s, l) xmlStringCurrentChar(NULL, s, &l)
#define NEXTL(l) ctxt->cur += l;
#define XML_REG_STRING_SEPARATOR '|'

/**
 * 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,
    XML_REGEXP_SINK_STATE
} xmlRegStateType;

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

typedef struct _xmlRegRange xmlRegRange;
typedef xmlRegRange *xmlRegRangePtr;

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

typedef struct _xmlRegAtom xmlRegAtom;
typedef xmlRegAtom *xmlRegAtomPtr;

typedef struct _xmlAutomataState xmlRegState;
typedef xmlRegState *xmlRegStatePtr;

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

    void *valuep;
    void *valuep2;
    int neg;
    int codepoint;
    xmlRegStatePtr start;
    xmlRegStatePtr 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;
    xmlRegMarkedType reached;
    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;
    /*
     * That's the compact form for determinists automatas
     */
    int nbstates;
    int *compact;
    void **transdata;
    int nbstrings;
    xmlChar **stringMap;
};

typedef struct _xmlRegExecRollback xmlRegExecRollback;
typedef xmlRegExecRollback *xmlRegExecRollbackPtr;

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

typedef struct _xmlRegInputToken xmlRegInputToken;
typedef xmlRegInputToken *xmlRegInputTokenPtr;

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

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

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

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

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

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

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

#define REGEXP_ALL_COUNTER	0x123456
#define REGEXP_ALL_LAX_COUNTER	0x123457

static void xmlFAParseRegExp(xmlRegParserCtxtPtr ctxt, int top);
static void xmlRegFreeState(xmlRegStatePtr state);
static void xmlRegFreeAtom(xmlRegAtomPtr atom);

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

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

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

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

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

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

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

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

	stateRemap = xmlMalloc(ret->nbStates * sizeof(int));
	if (stateRemap == NULL) {
	    xmlRegexpErrMemory(ctxt, "compiling regexp");
	    xmlFree(ret);
	    return(NULL);
	}
	for (i = 0;i < ret->nbStates;i++) {
	    if (ret->states[i] != NULL) {
		stateRemap[i] = nbstates;
		nbstates++;
	    } else {
		stateRemap[i] = -1;
	    }
	}
#ifdef DEBUG_COMPACTION
	printf("Final: %d states\n", nbstates);
#endif
	stringMap = xmlMalloc(ret->nbAtoms * sizeof(char *));
	if (stringMap == NULL) {
	    xmlRegexpErrMemory(ctxt, "compiling regexp");
	    xmlFree(stateRemap);
	    xmlFree(ret);