xpath.c

SIP 1.5.0源代码

/*
 * xpath.c: XML Path Language implementation
 *          XPath is a language for addressing parts of an XML document,
 *          designed to be used by both XSLT and XPointer.
 *
 * Reference: W3C Working Draft internal 5 July 1999
 *     http://www.w3.org/Style/XSL/Group/1999/07/xpath-19990705.html
 * Public reference:
 *     http://www.w3.org/TR/WD-xpath/
 *
 * See COPYRIGHT for the status of this software
 *
 * Author: [e-mail]
 */

#include "global.h"
#ifdef WIN32
#include "win32config.h"
#else
#include "config.h"
#endif

#include "xmlversion.h"
#ifdef LIBXML_XPATH_ENABLED

#include <stdio.h>
#include <string.h>

#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_MATH_H
#include <math.h>
#endif
#ifdef HAVE_MATH_H
#include <float.h>
#endif
#ifdef HAVE_IEEEFP_H
#include <ieeefp.h>
#endif
#ifdef HAVE_NAN_H
#include <nan.h>
#endif
#ifdef HAVE_CTYPE_H
#include <ctype.h>
#endif

#include <libxml/xmlmemory.h>
#include <libxml/tree.h>
#include <libxml/valid.h>
#include <libxml/xpath.h>
#include <libxml/parserInternals.h>

/* #define DEBUG */
/* #define DEBUG_STEP */
/* #define DEBUG_EXPR */

/*
 * Setup stuff for floating point
 * The lack of portability of this section of the libc is annoying !
 */
double xmlXPathNAN = 0;
double xmlXPathPINF = 1;
double xmlXPathMINF = -1;

#ifndef isinf
#ifndef HAVE_ISINF

#if HAVE_FPCLASS

int isinf(double d) {
    fpclass_t	type = fpclass(d);
    switch (type) {
	case FP_NINF:
	    return(-1);
	case FP_PINF:
	    return(1);
    }
    return(0);
}

#elif defined(HAVE_FP_CLASS) || defined(HAVE_FP_CLASS_D)

#if HAVE_FP_CLASS_H
#include <fp_class.h>
#endif

int isinf(double d) {
#if HAVE_FP_CLASS
    int	fpclass = fp_class(d);
#else
    int	fpclass = fp_class_d(d);
#endif
    if (fpclass == FP_POS_INF)
	return(1);
    if (fpclass == FP_NEG_INF)
	return(-1);
    return(0);
}

#elif defined(HAVE_CLASS)

int isinf(double d) {
    int	fpclass = class(d);
    if (fpclass == FP_PLUS_INF)
	return(1);
    if (fpclass == FP_MINUS_INF)
	return(-1);
    return(0);
}
#elif defined(finite) || defined(HAVE_FINITE)
int isinf(double x) { return !finite(x) && x==x; }
#elif defined(HUGE_VAL)
int isinf(double x)
{
    if (x == HUGE_VAL)
        return(1);
    if (x == -HUGE_VAL)
        return(-1);
    return(0);
}
#endif 

#endif /* ! HAVE_ISINF */
#endif /* ! defined(isinf) */

#ifndef isnan
#ifndef HAVE_ISNAN

#ifdef HAVE_ISNAND
#define isnan(f) isnand(f)
#endif /* HAVE_iSNAND */

#endif /* ! HAVE_iSNAN */
#endif /* ! defined(isnan) */

/**
 * xmlXPathInit:
 *
 * Initialize the XPath environment
 */
void
xmlXPathInit(void) {
    static int initialized = 0;

    if (initialized) return;

    xmlXPathNAN = 0;
    xmlXPathNAN /= 0;

    xmlXPathPINF = 1;
    xmlXPathPINF /= 0;

    xmlXPathMINF = -1;
    xmlXPathMINF /= 0;

    initialized = 1;
}

FILE *xmlXPathDebug = NULL;

#define TODO 								\
    fprintf(xmlXPathDebug, "Unimplemented block at %s:%d\n",		\
            __FILE__, __LINE__);

#define STRANGE 							\
    fprintf(xmlXPathDebug, "Internal error at %s:%d\n",			\
            __FILE__, __LINE__);

double xmlXPathStringEvalNumber(const xmlChar *str);
void xmlXPathStringFunction(xmlXPathParserContextPtr ctxt, int nargs);

/************************************************************************
 *									*
 * 		Parser stacks related functions and macros		*
 *									*
 ************************************************************************/

/*
 * Generic function for accessing stacks in the Parser Context
 */

#define PUSH_AND_POP(type, name)					\
extern int name##Push(xmlXPathParserContextPtr ctxt, type value) {	\
    if (ctxt->name##Nr >= ctxt->name##Max) {				\
	ctxt->name##Max *= 2;						\
        ctxt->name##Tab = (void *) xmlRealloc(ctxt->name##Tab,		\
	             ctxt->name##Max * sizeof(ctxt->name##Tab[0]));	\
        if (ctxt->name##Tab == NULL) {					\
	    fprintf(xmlXPathDebug, "realloc failed !\n");		\
	    return(0);							\
	}								\
    }									\
    ctxt->name##Tab[ctxt->name##Nr] = value;				\
    ctxt->name = value;							\
    return(ctxt->name##Nr++);						\
}									\
extern type name##Pop(xmlXPathParserContextPtr ctxt) {			\
    type ret;								\
    if (ctxt->name##Nr <= 0) return(0);					\
    ctxt->name##Nr--;							\
    if (ctxt->name##Nr > 0)						\
	ctxt->name = ctxt->name##Tab[ctxt->name##Nr - 1];		\
    else								\
        ctxt->name = NULL;						\
    ret = ctxt->name##Tab[ctxt->name##Nr];				\
    ctxt->name##Tab[ctxt->name##Nr] = 0;				\
    return(ret);							\
}									\

PUSH_AND_POP(xmlXPathObjectPtr, value)

/*
 * Macros for accessing the content. Those should be used only by the parser,
 * and not exported.
 *
 * Dirty macros, i.e. one need to make assumption on the context to use them
 *
 *   CUR_PTR return the current pointer to the xmlChar to be parsed.
 *   CUR     returns the current xmlChar value, i.e. a 8 bit value
 *           in ISO-Latin or UTF-8.
 *           This should be used internally by the parser
 *           only to compare to ASCII values otherwise it would break when
 *           running with UTF-8 encoding.
 *   NXT(n)  returns the n'th next xmlChar. Same as CUR is should be used only
 *           to compare on ASCII based substring.
 *   SKIP(n) Skip n xmlChar, and must also be used only to skip ASCII defined
 *           strings within the parser.
 *   CURRENT Returns the current char value, with the full decoding of
 *           UTF-8 if we are using this mode. It returns an int.
 *   NEXT    Skip to the next character, this does the proper decoding
 *           in UTF-8 mode. It also pop-up unfinished entities on the fly.
 *           It returns the pointer to the current xmlChar.
 */

#define CUR (*ctxt->cur)
#define SKIP(val) ctxt->cur += (val)
#define NXT(val) ctxt->cur[(val)]
#define CUR_PTR ctxt->cur

#define SKIP_BLANKS 							\
    while (IS_BLANK(*(ctxt->cur))) NEXT

#define CURRENT (*ctxt->cur)
#define NEXT ((*ctxt->cur) ?  ctxt->cur++: ctxt->cur)

/************************************************************************
 *									*
 *			Error handling routines				*
 *									*
 ************************************************************************/

#define XPATH_EXPRESSION_OK		0
#define XPATH_NUMBER_ERROR		1
#define XPATH_UNFINISHED_LITERAL_ERROR	2
#define XPATH_START_LITERAL_ERROR	3
#define XPATH_VARIABLE_REF_ERROR	4
#define XPATH_UNDEF_VARIABLE_ERROR	5
#define XPATH_INVALID_PREDICATE_ERROR	6
#define XPATH_EXPR_ERROR		7
#define XPATH_UNCLOSED_ERROR		8
#define XPATH_UNKNOWN_FUNC_ERROR	9
#define XPATH_INVALID_OPERAND		10
#define XPATH_INVALID_TYPE		11
#define XPATH_INVALID_ARITY		12

const char *xmlXPathErrorMessages[] = {
    "Ok",
    "Number encoding",
    "Unfinished litteral",
    "Start of litteral",
    "Expected $ for variable reference",
    "Undefined variable",
    "Invalid predicate",
    "Invalid expression",
    "Missing closing curly brace",
    "Unregistered function",
    "Invalid operand",
    "Invalid type",
    "Invalid number of arguments",
};

/**
 * xmlXPathError:
 * @ctxt:  the XPath Parser context
 * @file:  the file name
 * @line:  the line number
 * @no:  the error number
 *
 * Create a new xmlNodeSetPtr of type double and of value @val
 *
 * Returns the newly created object.
 */
void
xmlXPatherror(xmlXPathParserContextPtr ctxt, const char *file,
              int line, int no) {
    int n;
    const xmlChar *cur;
    const xmlChar *base;

    fprintf(xmlXPathDebug, "Error %s:%d: %s\n", file, line,
            xmlXPathErrorMessages[no]);

    cur = ctxt->cur;
    base = ctxt->base;
    while ((cur > base) && ((*cur == '\n') || (*cur == '\r'))) {
	cur--;
    }
    n = 0;
    while ((n++ < 80) && (cur > base) && (*cur != '\n') && (*cur != '\r'))
        cur--;
    if ((*cur == '\n') || (*cur == '\r')) cur++;
    base = cur;
    n = 0;
    while ((*cur != 0) && (*cur != '\n') && (*cur != '\r') && (n < 79)) {
        fprintf(xmlXPathDebug, "%c", (unsigned char) *cur++);
	n++;
    }
    fprintf(xmlXPathDebug, "\n");
    cur = ctxt->cur;
    while ((*cur == '\n') || (*cur == '\r'))
	cur--;
    n = 0;
    while ((cur != base) && (n++ < 80)) {
        fprintf(xmlXPathDebug, " ");
        base++;
    }
    fprintf(xmlXPathDebug,"^\n");
}

#define CHECK_ERROR							\
    if (ctxt->error != XPATH_EXPRESSION_OK) return

#ifdef WIN32
#undef ERROR
#endif
#define ERROR(X)							\
    { xmlXPatherror(ctxt, __FILE__, __LINE__, X);			\
      ctxt->error = (X); return; }

#define ERROR0(X)							\
    { xmlXPatherror(ctxt, __FILE__, __LINE__, X);			\
      ctxt->error = (X); return(0); }

#define CHECK_TYPE(typeval)						\
    if ((ctxt->value == NULL) || (ctxt->value->type != typeval))	\
        ERROR(XPATH_INVALID_TYPE)					\


/************************************************************************
 *									*
 *			Routines to handle NodeSets			*
 *									*
 ************************************************************************/

#define XML_NODESET_DEFAULT	10
/**
 * xmlXPathNodeSetCreate:
 * @val:  an initial xmlNodePtr, or NULL
 *
 * Create a new xmlNodeSetPtr of type double and of value @val
 *
 * Returns the newly created object.
 */
xmlNodeSetPtr
xmlXPathNodeSetCreate(xmlNodePtr val) {
    xmlNodeSetPtr ret;

    ret = (xmlNodeSetPtr) xmlMalloc(sizeof(xmlNodeSet));
    if (ret == NULL) {
        fprintf(xmlXPathDebug, "xmlXPathNewNodeSet: out of memory\n");
	return(NULL);
    }
    memset(ret, 0 , (size_t) sizeof(xmlNodeSet));
    if (val != NULL) {
        ret->nodeTab = (xmlNodePtr *) xmlMalloc(XML_NODESET_DEFAULT *
					     sizeof(xmlNodePtr));
	if (ret->nodeTab == NULL) {
	    fprintf(xmlXPathDebug, "xmlXPathNewNodeSet: out of memory\n");
	    return(NULL);
	}
	memset(ret->nodeTab, 0 ,
	       XML_NODESET_DEFAULT * (size_t) sizeof(xmlNodePtr));
        ret->nodeMax = XML_NODESET_DEFAULT;
	ret->nodeTab[ret->nodeNr++] = val;
    }
    return(ret);
}

/**
 * xmlXPathNodeSetAdd:
 * @cur:  the initial node set
 * @val:  a new xmlNodePtr
 *
 * add a new xmlNodePtr ot an existing NodeSet
 */
void
xmlXPathNodeSetAdd(xmlNodeSetPtr cur, xmlNodePtr val) {
    int i;

    if (val == NULL) return;

    /*
     * check against doublons
     */
    for (i = 0;i < cur->nodeNr;i++)
        if (cur->nodeTab[i] == val) return;

    /*
     * grow the nodeTab if needed
     */
    if (cur->nodeMax == 0) {
        cur->nodeTab = (xmlNodePtr *) xmlMalloc(XML_NODESET_DEFAULT *
					     sizeof(xmlNodePtr));
	if (cur->nodeTab == NULL) {
	    fprintf(xmlXPathDebug, "xmlXPathNodeSetAdd: out of memory\n");
	    return;
	}
	memset(cur->nodeTab, 0 ,
	       XML_NODESET_DEFAULT * (size_t) sizeof(xmlNodePtr));
        cur->nodeMax = XML_NODESET_DEFAULT;
    } else if (cur->nodeNr == cur->nodeMax) {
        xmlNodePtr *temp;

        cur->nodeMax *= 2;
	temp = (xmlNodePtr *) xmlRealloc(cur->nodeTab, cur->nodeMax *
				      sizeof(xmlNodePtr));
	if (temp == NULL) {
	    fprintf(xmlXPathDebug, "xmlXPathNodeSetAdd: out of memory\n");
	    return;
	}
	cur->nodeTab = temp;
    }
    cur->nodeTab[cur->nodeNr++] = val;
}

/**
 * xmlXPathNodeSetMerge:
 * @val1:  the first NodeSet
 * @val2:  the second NodeSet
 *
 * Merges two nodesets, all nodes from @val2 are added to @val1
 *
 * Returns val1 once extended or NULL in case of error.
 */
xmlNodeSetPtr
xmlXPathNodeSetMerge(xmlNodeSetPtr val1, xmlNodeSetPtr val2) {
    int i;

    if (val1 == NULL) return(NULL);
    if (val2 == NULL) return(val1);

    /*
     * !!!!! this can be optimized a lot, knowing that both
     *       val1 and val2 already have unicity of their values.
     */

    for (i = 0;i < val2->nodeNr;i++)
        xmlXPathNodeSetAdd(val1, val2->nodeTab[i]);

    return(val1);
}

/**
 * xmlXPathNodeSetDel:
 * @cur:  the initial node set
 * @val:  an xmlNodePtr
 *
 * Removes an xmlNodePtr from an existing NodeSet
 */
void
xmlXPathNodeSetDel(xmlNodeSetPtr cur, xmlNodePtr val) {
    int i;

    if (cur == NULL) return;
    if (val == NULL) return;

    /*
     * check against doublons
     */
    for (i = 0;i < cur->nodeNr;i++)
        if (cur->nodeTab[i] == val) break;