/src/libxml2/pattern.c

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/*
 * pattern.c: Implementation of selectors for nodes
 *
 * Reference:
 *   http://www.w3.org/TR/2001/REC-xmlschema-1-20010502/
 *   to some extent
 *   http://www.w3.org/TR/1999/REC-xml-19991116
 *
 * See Copyright for the status of this software.
 *
 * daniel@veillard.com
 */

/*
 * TODO:
 * - compilation flags to check for specific syntaxes
 *   using flags of xmlPatterncompile()
 * - making clear how pattern starting with / or . need to be handled,
 *   currently push(NULL, NULL) means a reset of the streaming context
 *   and indicating we are on / (the document node), probably need
 *   something similar for .
 * - get rid of the "compile" starting with lowercase
 * - DONE (2006-05-16): get rid of the Strdup/Strndup in case of dictionary
 */

#define IN_LIBXML
#include "libxml.h"

#include <string.h>
#include <libxml/pattern.h>
#include <libxml/xmlmemory.h>
#include <libxml/tree.h>
#include <libxml/dict.h>
#include <libxml/xmlerror.h>
#include <libxml/parserInternals.h>

#ifdef LIBXML_PATTERN_ENABLED

#ifdef ERROR
#undef ERROR
#endif
#define ERROR(a, b, c, d)
#define ERROR5(a, b, c, d, e)

#define XML_STREAM_STEP_DESC  1
#define XML_STREAM_STEP_FINAL 2
#define XML_STREAM_STEP_ROOT  4
#define XML_STREAM_STEP_ATTR  8
#define XML_STREAM_STEP_NODE  16
#define XML_STREAM_STEP_IN_SET  32

/*
* NOTE: Those private flags (XML_STREAM_xxx) are used
*   in _xmlStreamCtxt->flag. They extend the public
*   xmlPatternFlags, so be careful not to interfere with the
*   reserved values for xmlPatternFlags.
*/
#define XML_STREAM_FINAL_IS_ANY_NODE 1<<14
#define XML_STREAM_FROM_ROOT 1<<15
#define XML_STREAM_DESC 1<<16

/*
* XML_STREAM_ANY_NODE is used for comparison against
* xmlElementType enums, to indicate a node of any type.
*/
#define XML_STREAM_ANY_NODE 100

#define XML_PATTERN_NOTPATTERN  (XML_PATTERN_XPATH | \
         XML_PATTERN_XSSEL | \
         XML_PATTERN_XSFIELD)

#define XML_STREAM_XS_IDC(c) ((c)->flags & \
    (XML_PATTERN_XSSEL | XML_PATTERN_XSFIELD))

#define XML_STREAM_XS_IDC_SEL(c) ((c)->flags & XML_PATTERN_XSSEL)

#define XML_STREAM_XS_IDC_FIELD(c) ((c)->flags & XML_PATTERN_XSFIELD)

#define XML_PAT_COPY_NSNAME(c, r, nsname) \
    if ((c)->comp->dict) \
  r = (xmlChar *) xmlDictLookup((c)->comp->dict, BAD_CAST nsname, -1); \
    else r = xmlStrdup(BAD_CAST nsname);

#define XML_PAT_FREE_STRING(c, r) if ((c)->comp->dict == NULL) xmlFree(r);

typedef struct _xmlStreamStep xmlStreamStep;
typedef xmlStreamStep *xmlStreamStepPtr;
struct _xmlStreamStep {
    int flags;      /* properties of that step */
    const xmlChar *name;  /* first string value if NULL accept all */
    const xmlChar *ns;    /* second string value */
    int nodeType;   /* type of node */
};

typedef struct _xmlStreamComp xmlStreamComp;
typedef xmlStreamComp *xmlStreamCompPtr;
struct _xmlStreamComp {
    xmlDict *dict;    /* the dictionary if any */
    int nbStep;     /* number of steps in the automata */
    int maxStep;    /* allocated number of steps */
    xmlStreamStepPtr steps; /* the array of steps */
    int flags;
};

struct _xmlStreamCtxt {
    struct _xmlStreamCtxt *next;/* link to next sub pattern if | */
    xmlStreamCompPtr comp;  /* the compiled stream */
    int nbState;    /* number of states in the automata */
    int maxState;   /* allocated number of states */
    int level;      /* how deep are we ? */
    int *states;    /* the array of step indexes */
    int flags;      /* validation options */
    int blockLevel;
};

static void xmlFreeStreamComp(xmlStreamCompPtr comp);

/*
 * Types are private:
 */

typedef enum {
    XML_OP_END=0,
    XML_OP_ROOT,
    XML_OP_ELEM,
    XML_OP_CHILD,
    XML_OP_ATTR,
    XML_OP_PARENT,
    XML_OP_ANCESTOR,
    XML_OP_NS,
    XML_OP_ALL
} xmlPatOp;


typedef struct _xmlStepState xmlStepState;
typedef xmlStepState *xmlStepStatePtr;
struct _xmlStepState {
    int step;
    xmlNodePtr node;
};

typedef struct _xmlStepStates xmlStepStates;
typedef xmlStepStates *xmlStepStatesPtr;
struct _xmlStepStates {
    int nbstates;
    int maxstates;
    xmlStepStatePtr states;
};

typedef struct _xmlStepOp xmlStepOp;
typedef xmlStepOp *xmlStepOpPtr;
struct _xmlStepOp {
    xmlPatOp op;
    const xmlChar *value;
    const xmlChar *value2; /* The namespace name */
};

#define PAT_FROM_ROOT (1<<8)
#define PAT_FROM_CUR  (1<<9)

struct _xmlPattern {
    void *data;   /* the associated template */
    xmlDictPtr dict;    /* the optional dictionary */
    struct _xmlPattern *next; /* next pattern if | is used */
    const xmlChar *pattern; /* the pattern */
    int flags;      /* flags */
    int nbStep;
    int maxStep;
    xmlStepOpPtr steps;        /* ops for computation */
    xmlStreamCompPtr stream;  /* the streaming data if any */
};

typedef struct _xmlPatParserContext xmlPatParserContext;
typedef xmlPatParserContext *xmlPatParserContextPtr;
struct _xmlPatParserContext {
    const xmlChar *cur;     /* the current char being parsed */
    const xmlChar *base;    /* the full expression */
    int            error;   /* error code */
    xmlDictPtr     dict;    /* the dictionary if any */
    xmlPatternPtr  comp;    /* the result */
    xmlNodePtr     elem;    /* the current node if any */
    const xmlChar **namespaces;   /* the namespaces definitions */
    int   nb_namespaces;    /* the number of namespaces */
};

/************************************************************************
 *                  *
 *      Type functions          *
 *                  *
 ************************************************************************/

/**
 * xmlNewPattern:
 *
 * Create a new XSLT Pattern
 *
 * Returns the newly allocated xmlPatternPtr or NULL in case of error
 */
static xmlPatternPtr
xmlNewPattern(void) {
    xmlPatternPtr cur;

    cur = (xmlPatternPtr) xmlMalloc(sizeof(xmlPattern));
    if (cur == NULL) {
  ERROR(NULL, NULL, NULL,
    "xmlNewPattern : malloc failed\n");
  return(NULL);
    }
    memset(cur, 0, sizeof(xmlPattern));
    cur->maxStep = 10;
    cur->steps = (xmlStepOpPtr) xmlMalloc(cur->maxStep * sizeof(xmlStepOp));
    if (cur->steps == NULL) {
        xmlFree(cur);
  ERROR(NULL, NULL, NULL,
    "xmlNewPattern : malloc failed\n");
  return(NULL);
    }
    return(cur);
}

/**
 * xmlFreePattern:
 * @comp:  an XSLT comp
 *
 * Free up the memory allocated by @comp
 */
void
xmlFreePattern(xmlPatternPtr comp) {
    xmlFreePatternList(comp);
}

static void
xmlFreePatternInternal(xmlPatternPtr comp) {
    xmlStepOpPtr op;
    int i;

    if (comp == NULL)
  return;
    if (comp->stream != NULL)
        xmlFreeStreamComp(comp->stream);
    if (comp->pattern != NULL)
  xmlFree((xmlChar *)comp->pattern);
    if (comp->steps != NULL) {
        if (comp->dict == NULL) {
      for (i = 0;i < comp->nbStep;i++) {
    op = &comp->steps[i];
    if (op->value != NULL)
        xmlFree((xmlChar *) op->value);
    if (op->value2 != NULL)
        xmlFree((xmlChar *) op->value2);
      }
  }
  xmlFree(comp->steps);
    }
    if (comp->dict != NULL)
        xmlDictFree(comp->dict);

    memset(comp, -1, sizeof(xmlPattern));
    xmlFree(comp);
}

/**
 * xmlFreePatternList:
 * @comp:  an XSLT comp list
 *
 * Free up the memory allocated by all the elements of @comp
 */
void
xmlFreePatternList(xmlPatternPtr comp) {
    xmlPatternPtr cur;

    while (comp != NULL) {
  cur = comp;
  comp = comp->next;
  cur->next = NULL;
  xmlFreePatternInternal(cur);
    }
}

/**
 * xmlNewPatParserContext:
 * @pattern:  the pattern context
 * @dict:  the inherited dictionary or NULL
 * @namespaces: the prefix definitions, array of [URI, prefix] terminated
 *              with [NULL, NULL] or NULL if no namespace is used
 *
 * Create a new XML pattern parser context
 *
 * Returns the newly allocated xmlPatParserContextPtr or NULL in case of error
 */
static xmlPatParserContextPtr
xmlNewPatParserContext(const xmlChar *pattern, xmlDictPtr dict,
                       const xmlChar **namespaces) {
    xmlPatParserContextPtr cur;

    if (pattern == NULL)
        return(NULL);

    cur = (xmlPatParserContextPtr) xmlMalloc(sizeof(xmlPatParserContext));
    if (cur == NULL) {
  ERROR(NULL, NULL, NULL,
    "xmlNewPatParserContext : malloc failed\n");
  return(NULL);
    }
    memset(cur, 0, sizeof(xmlPatParserContext));
    cur->dict = dict;
    cur->cur = pattern;
    cur->base = pattern;
    if (namespaces != NULL) {
        int i;
        for (i = 0;namespaces[2 * i] != NULL;i++)
            ;
        cur->nb_namespaces = i;
    } else {
        cur->nb_namespaces = 0;
    }
    cur->namespaces = namespaces;
    return(cur);
}

/**
 * xmlFreePatParserContext:
 * @ctxt:  an XSLT parser context
 *
 * Free up the memory allocated by @ctxt
 */
static void
xmlFreePatParserContext(xmlPatParserContextPtr ctxt) {
    if (ctxt == NULL)
  return;
    memset(ctxt, -1, sizeof(xmlPatParserContext));
    xmlFree(ctxt);
}

/**
 * xmlPatternAdd:
 * @comp:  the compiled match expression
 * @op:  an op
 * @value:  the first value
 * @value2:  the second value
 *
 * Add a step to an XSLT Compiled Match
 *
 * Returns -1 in case of failure, 0 otherwise.
 */
static int
xmlPatternAdd(xmlPatParserContextPtr ctxt, xmlPatternPtr comp,
              xmlPatOp op, xmlChar * value, xmlChar * value2)
{
    if (comp->nbStep >= comp->maxStep) {
        xmlStepOpPtr temp;
  temp = (xmlStepOpPtr) xmlRealloc(comp->steps, comp->maxStep * 2 *
                                   sizeof(xmlStepOp));
        if (temp == NULL) {
      ERROR(ctxt, NULL, NULL,
           "xmlPatternAdd: realloc failed\n");
            ctxt->error = -1;
      return (-1);
  }
  comp->steps = temp;
  comp->maxStep *= 2;
    }
    comp->steps[comp->nbStep].op = op;
    comp->steps[comp->nbStep].value = value;
    comp->steps[comp->nbStep].value2 = value2;
    comp->nbStep++;
    return (0);
}

/**
 * xmlReversePattern:
 * @comp:  the compiled match expression
 *
 * reverse all the stack of expressions
 *
 * returns 0 in case of success and -1 in case of error.
 */
static int
xmlReversePattern(xmlPatternPtr comp) {
    int i, j;

    /*
     * remove the leading // for //a or .//a
     */
    if ((comp->nbStep > 0) && (comp->steps[0].op == XML_OP_ANCESTOR)) {
        for (i = 0, j = 1;j < comp->nbStep;i++,j++) {
      comp->steps[i].value = comp->steps[j].value;
      comp->steps[i].value2 = comp->steps[j].value2;
      comp->steps[i].op = comp->steps[j].op;
  }
  comp->nbStep--;
    }
    if (comp->nbStep >= comp->maxStep) {
        xmlStepOpPtr temp;
  temp = (xmlStepOpPtr) xmlRealloc(comp->steps, comp->maxStep * 2 *
                                   sizeof(xmlStepOp));
        if (temp == NULL) {
      ERROR(ctxt, NULL, NULL,
           "xmlReversePattern: realloc failed\n");
      return (-1);
  }
  comp->steps = temp;
  comp->maxStep *= 2;
    }
    i = 0;
    j = comp->nbStep - 1;
    while (j > i) {
  register const xmlChar *tmp;
  register xmlPatOp op;
  tmp = comp->steps[i].value;
  comp->steps[i].value = comp->steps[j].value;
  comp->steps[j].value = tmp;
  tmp = comp->steps[i].value2;
  comp->steps[i].value2 = comp->steps[j].value2;
  comp->steps[j].value2 = tmp;
  op = comp->steps[i].op;
  comp->steps[i].op = comp->steps[j].op;
  comp->steps[j].op = op;
  j--;
  i++;
    }
    comp->steps[comp->nbStep].value = NULL;
    comp->steps[comp->nbStep].value2 = NULL;
    comp->steps[comp->nbStep++].op = XML_OP_END;
    return(0);
}

/************************************************************************
 *                  *
 *    The interpreter for the precompiled patterns    *
 *                  *
 ************************************************************************/

static int
xmlPatPushState(xmlStepStates *states, int step, xmlNodePtr node) {
    if (states->maxstates <= states->nbstates) {
        size_t newSize = states->maxstates ? states->maxstates * 2 : 4;
        xmlStepState *tmp;

  tmp = xmlRealloc(states->states, newSize * sizeof(tmp[0]));
  if (tmp == NULL)
      return(-1);
  states->states = tmp;
  states->maxstates *= 2;
    }
    states->states[states->nbstates].step = step;
    states->states[states->nbstates++].node = node;
    return(0);
}

/**
 * xmlPatMatch:
 * @comp: the precompiled pattern
 * @node: a node
 *
 * Test whether the node matches the pattern
 *
 * Returns 1 if it matches, 0 if it doesn't and -1 in case of failure
 */
static int
xmlPatMatch(xmlPatternPtr comp, xmlNodePtr node) {
    int i;
    xmlStepOpPtr step;
    xmlStepStates states = {0, 0, NULL}; /* // may require backtrack */

    if ((comp == NULL) || (node == NULL)) return(-1);
    i = 0;
restart:
    for (;i < comp->nbStep;i++) {
  step = &comp->steps[i];
  switch (step->op) {
            case XML_OP_END:
    goto found;
            case XML_OP_ROOT:
    if (node->type == XML_NAMESPACE_DECL)
        goto rollback;
    node = node->parent;
    if ((node->type == XML_DOCUMENT_NODE) ||
        (node->type == XML_HTML_DOCUMENT_NODE))
        continue;
    goto rollback;
            case XML_OP_ELEM:
    if (node->type != XML_ELEMENT_NODE)
        goto rollback;
    if (step->value == NULL)
        continue;
    if (step->value[0] != node->name[0])
        goto rollback;
    if (!xmlStrEqual(step->value, node->name))
        goto rollback;

    /* Namespace test */
    if (node->ns == NULL) {
        if (step->value2 != NULL)
      goto rollback;
    } else if (node->ns->href != NULL) {
        if (step->value2 == NULL)
      goto rollback;
        if (!xmlStrEqual(step->value2, node->ns->href))
      goto rollback;
    }
    continue;
            case XML_OP_CHILD: {
    xmlNodePtr lst;

    if ((node->type != XML_ELEMENT_NODE) &&
        (node->type != XML_DOCUMENT_NODE) &&
        (node->type != XML_HTML_DOCUMENT_NODE))
        goto rollback;

    lst = node->children;

    if (step->value != NULL) {
        while (lst != NULL) {
      if ((lst->type == XML_ELEMENT_NODE) &&
          (step->value[0] == lst->name[0]) &&
          (xmlStrEqual(step->value, lst->name)))
          break;
      lst = lst->next;
        }
        if (lst != NULL)
      continue;
    }
    goto rollback;
      }
            case XML_OP_ATTR:
    if (node->type != XML_ATTRIBUTE_NODE)
        goto rollback;
    if (step->value != NULL) {
        if (step->value[0] != node->name[0])
      goto rollback;
        if (!xmlStrEqual(step->value, node->name))
      goto rollback;
    }
    /* Namespace test */
    if (node->ns == NULL) {
        if (step->value2 != NULL)
      goto rollback;
    } else if (step->value2 != NULL) {
        if (!xmlStrEqual(step->value2, node->ns->href))
      goto rollback;
    }
    continue;
            case XML_OP_PARENT:
    if ((node->type == XML_DOCUMENT_NODE) ||
        (node->type == XML_HTML_DOCUMENT_NODE) ||
        (node->type == XML_NAMESPACE_DECL))
        goto rollback;
    node = node->parent;
    if (node == NULL)
        goto rollback;
    if (step->value == NULL)
        continue;
    if (step->value[0] != node->name[0])
        goto rollback;
    if (!xmlStrEqual(step->value, node->name))
        goto rollback;
    /* Namespace test */
    if (node->ns == NULL) {
        if (step->value2 != NULL)
      goto rollback;
    } else if (node->ns->href != NULL) {
        if (step->value2 == NULL)
      goto rollback;
        if (!xmlStrEqual(step->value2, node->ns->href))
      goto rollback;
    }
    continue;
            case XML_OP_ANCESTOR:
    /* TODO: implement coalescing of ANCESTOR/NODE ops */
    if (step->value == NULL) {
        i++;
        step = &comp->steps[i];
        if (step->op == XML_OP_ROOT)
      goto found;
        if (step->op != XML_OP_ELEM)
      goto rollback;
        if (step->value == NULL)
      return(-1);
    }
    if (node == NULL)
        goto rollback;
    if ((node->type == XML_DOCUMENT_NODE) ||
        (node->type == XML_HTML_DOCUMENT_NODE) ||
        (node->type == XML_NAMESPACE_DECL))
        goto rollback;
    node = node->parent;
    while (node != NULL) {
        if ((node->type == XML_ELEMENT_NODE) &&
      (step->value[0] == node->name[0]) &&
      (xmlStrEqual(step->value, node->name))) {
      /* Namespace test */
      if (node->ns == NULL) {
          if (step->value2 == NULL)
        break;
      } else if (node->ns->href != NULL) {
          if ((step->value2 != NULL) &&
              (xmlStrEqual(step->value2, node->ns->href)))
        break;
      }
        }
        node = node->parent;
    }
    if (node == NULL)
        goto rollback;
    /*
     * prepare a potential rollback from here
     * for ancestors of that node.
     */
    if (step->op == XML_OP_ANCESTOR)
        xmlPatPushState(&states, i, node);
    else
        xmlPatPushState(&states, i - 1, node);
    continue;
            case XML_OP_NS:
    if (node->type != XML_ELEMENT_NODE)
        goto rollback;
    if (node->ns == NULL) {
        if (step->value != NULL)
      goto rollback;
    } else if (node->ns->href != NULL) {
        if (step->value == NULL)
      goto rollback;
        if (!xmlStrEqual(step->value, node->ns->href))
      goto rollback;
    }
    break;
            case XML_OP_ALL:
    if (node->type != XML_ELEMENT_NODE)
        goto rollback;
    break;
  }
    }
found:
    if (states.states != NULL) {
        /* Free the rollback states */
  xmlFree(states.states);
    }
    return(1);
rollback:
    /* got an error try to rollback */
    if (states.states == NULL)
  return(0);
    if (states.nbstates <= 0) {
  xmlFree(states.states);
  return(0);
    }
    states.nbstates--;
    i = states.states[states.nbstates].step;
    node = states.states[states.nbstates].node;
    goto restart;
}

/************************************************************************
 *                  *
 *      Dedicated parser for templates      *
 *                  *
 ************************************************************************/

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

#define SKIP_BLANKS             \
    while (IS_BLANK_CH(CUR)) NEXT

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


#define PUSH(op, val, val2)           \
    if (xmlPatternAdd(ctxt, ctxt->comp, (op), (val), (val2))) goto error;

/**
 * xmlPatScanName:
 * @ctxt:  the XPath Parser context
 *
 * [4] NameChar ::= Letter | Digit | '.' | '-' | '_' |
 *                  CombiningChar | Extender
 *
 * [5] Name ::= (Letter | '_' | ':') (NameChar)*
 *
 * [6] Names ::= Name (S Name)*
 *
 * Returns the Name parsed or NULL
 */

static xmlChar *
xmlPatScanName(xmlPatParserContextPtr ctxt) {
    const xmlChar *q, *cur;
    xmlChar *ret = NULL;
    int val, len;

    SKIP_BLANKS;

    cur = q = CUR_PTR;
    val = xmlStringCurrentChar(NULL, cur, &len);
    if (!IS_LETTER(val) && (val != '_') && (val != ':'))
  return(NULL);

    while ((IS_LETTER(val)) || (IS_DIGIT(val)) ||
           (val == '.') || (val == '-') ||
     (val == '_') ||
     (IS_COMBINING(val)) ||
     (IS_EXTENDER(val))) {
  cur += len;
  val = xmlStringCurrentChar(NULL, cur, &len);
    }
    if (ctxt->dict)
  ret = (xmlChar *) xmlDictLookup(ctxt->dict, q, cur - q);
    else
  ret = xmlStrndup(q, cur - q);
    CUR_PTR = cur;
    return(ret);
}

/**
 * xmlPatScanNCName:
 * @ctxt:  the XPath Parser context
 *
 * Parses a non qualified name
 *
 * Returns the Name parsed or NULL
 */

static xmlChar *
xmlPatScanNCName(xmlPatParserContextPtr ctxt) {
    const xmlChar *q, *cur;
    xmlChar *ret = NULL;
    int val, len;

    SKIP_BLANKS;

    cur = q = CUR_PTR;
    val = xmlStringCurrentChar(NULL, cur, &len);
    if (!IS_LETTER(val) && (val != '_'))
  return(NULL);

    while ((IS_LETTER(val)) || (IS_DIGIT(val)) ||
           (val == '.') || (val == '-') ||
     (val == '_') ||
     (IS_COMBINING(val)) ||
     (IS_EXTENDER(val))) {
  cur += len;
  val = xmlStringCurrentChar(NULL, cur, &len);
    }
    if (ctxt->dict)
  ret = (xmlChar *) xmlDictLookup(ctxt->dict, q, cur - q);
    else
  ret = xmlStrndup(q, cur - q);
    if (ret == NULL)
        ctxt->error = -1;
    CUR_PTR = cur;
    return(ret);
}

/**
 * xmlCompileAttributeTest:
 * @ctxt:  the compilation context
 *
 * Compile an attribute test.
 */
static void
xmlCompileAttributeTest(xmlPatParserContextPtr ctxt) {
    xmlChar *token = NULL;
    xmlChar *name = NULL;
    xmlChar *URL = NULL;

    SKIP_BLANKS;
    name = xmlPatScanNCName(ctxt);
    if (ctxt->error < 0)
        return;
    if (name == NULL) {
  if (CUR == '*') {
      PUSH(XML_OP_ATTR, NULL, NULL);
      NEXT;
  } else {
      ERROR(NULL, NULL, NULL,
    "xmlCompileAttributeTest : Name expected\n");
      ctxt->error = 1;
  }
  return;
    }
    if (CUR == ':') {
  int i;
  xmlChar *prefix = name;

  NEXT;

  if (IS_BLANK_CH(CUR)) {
      ERROR5(NULL, NULL, NULL, "Invalid QName.\n", NULL);
      ctxt->error = 1;
      goto error;
  }
  /*
  * This is a namespace match
  */
  token = xmlPatScanName(ctxt);
  if ((prefix[0] == 'x') &&
      (prefix[1] == 'm') &&
      (prefix[2] == 'l') &&
      (prefix[3] == 0))
  {
      XML_PAT_COPY_NSNAME(ctxt, URL, XML_XML_NAMESPACE);
  } else {
      for (i = 0;i < ctxt->nb_namespaces;i++) {
    if (xmlStrEqual(ctxt->namespaces[2 * i + 1], prefix)) {
        XML_PAT_COPY_NSNAME(ctxt, URL, ctxt->namespaces[2 * i])
        break;
    }
      }
      if (i >= ctxt->nb_namespaces) {
    ERROR5(NULL, NULL, NULL,
        "xmlCompileAttributeTest : no namespace bound to prefix %s\n",
        prefix);
    ctxt->error = 1;
    goto error;
      }
  }
        XML_PAT_FREE_STRING(ctxt, name);
        name = NULL;
  if (token == NULL) {
      if (CUR == '*') {
    NEXT;
    PUSH(XML_OP_ATTR, NULL, URL);
      } else {
    ERROR(NULL, NULL, NULL,
        "xmlCompileAttributeTest : Name expected\n");
    ctxt->error = 1;
    goto error;
      }
  } else {
      PUSH(XML_OP_ATTR, token, URL);
  }
    } else {
  PUSH(XML_OP_ATTR, name, NULL);
    }
    return;
error:
    if (name != NULL)
  XML_PAT_FREE_STRING(ctxt, name);
    if (URL != NULL)
  XML_PAT_FREE_STRING(ctxt, URL)
    if (token != NULL)
  XML_PAT_FREE_STRING(ctxt, token);
}

/**
 * xmlCompileStepPattern:
 * @ctxt:  the compilation context
 *
 * Compile the Step Pattern and generates a precompiled
 * form suitable for fast matching.
 *
 * [3]    Step    ::=    '.' | NameTest
 * [4]    NameTest    ::=    QName | '*' | NCName ':' '*'
 */

static void
xmlCompileStepPattern(xmlPatParserContextPtr ctxt) {
    xmlChar *token = NULL;
    xmlChar *name = NULL;
    xmlChar *URL = NULL;
    int hasBlanks = 0;

    SKIP_BLANKS;
    if (CUR == '.') {
  /*
  * Context node.
  */
  NEXT;
  PUSH(XML_OP_ELEM, NULL, NULL);
  return;
    }
    if (CUR == '@') {
  /*
  * Attribute test.
  */
  if (XML_STREAM_XS_IDC_SEL(ctxt->comp)) {
      ERROR5(NULL, NULL, NULL,
    "Unexpected attribute axis in '%s'.\n", ctxt->base);
      ctxt->error = 1;
      return;
  }
  NEXT;
  xmlCompileAttributeTest(ctxt);
  if (ctxt->error != 0)
      goto error;
  return;
    }
    name = xmlPatScanNCName(ctxt);
    if (ctxt->error < 0)
        return;
    if (name == NULL) {
  if (CUR == '*') {
      NEXT;
      PUSH(XML_OP_ALL, NULL, NULL);
      return;
  } else {
      ERROR(NULL, NULL, NULL,
        "xmlCompileStepPattern : Name expected\n");
      ctxt->error = 1;
      return;
  }
    }
    if (IS_BLANK_CH(CUR)) {
  hasBlanks = 1;
  SKIP_BLANKS;
    }
    if (CUR == ':') {
  NEXT;
  if (CUR != ':') {
      xmlChar *prefix = name;
      int i;

      if (hasBlanks || IS_BLANK_CH(CUR)) {
    ERROR5(NULL, NULL, NULL, "Invalid QName.\n", NULL);
    ctxt->error = 1;
    goto error;
      }
      /*
       * This is a namespace match
       */
      token = xmlPatScanName(ctxt);
      if ((prefix[0] == 'x') &&
    (prefix[1] == 'm') &&
    (prefix[2] == 'l') &&
    (prefix[3] == 0))
      {
    XML_PAT_COPY_NSNAME(ctxt, URL, XML_XML_NAMESPACE)
      } else {
    for (i = 0;i < ctxt->nb_namespaces;i++) {
        if (xmlStrEqual(ctxt->namespaces[2 * i + 1], prefix)) {
      XML_PAT_COPY_NSNAME(ctxt, URL, ctxt->namespaces[2 * i])
      break;
        }
    }
    if (i >= ctxt->nb_namespaces) {
        ERROR5(NULL, NULL, NULL,
      "xmlCompileStepPattern : no namespace bound to prefix %s\n",
      prefix);
        ctxt->error = 1;
        goto error;
    }
      }
      XML_PAT_FREE_STRING(ctxt, prefix);
      name = NULL;
      if (token == NULL) {
    if (CUR == '*') {
        NEXT;
        PUSH(XML_OP_NS, URL, NULL);
    } else {
        ERROR(NULL, NULL, NULL,
          "xmlCompileStepPattern : Name expected\n");
        ctxt->error = 1;
        goto error;
    }
      } else {
    PUSH(XML_OP_ELEM, token, URL);
      }
  } else {
      NEXT;
      if (xmlStrEqual(name, (const xmlChar *) "child")) {
    XML_PAT_FREE_STRING(ctxt, name);
    name = xmlPatScanName(ctxt);
    if (name == NULL) {
        if (CUR == '*') {
      NEXT;
      PUSH(XML_OP_ALL, NULL, NULL);
      return;
        } else {
      ERROR(NULL, NULL, NULL,
          "xmlCompileStepPattern : QName expected\n");
      ctxt->error = 1;
      goto error;
        }
    }
    if (CUR == ':') {
        xmlChar *prefix = name;
        int i;

        NEXT;
        if (IS_BLANK_CH(CUR)) {
      ERROR5(NULL, NULL, NULL, "Invalid QName.\n", NULL);
      ctxt->error = 1;
      goto error;
        }
        /*
        * This is a namespace match
        */
        token = xmlPatScanName(ctxt);
        if ((prefix[0] == 'x') &&
      (prefix[1] == 'm') &&
      (prefix[2] == 'l') &&
      (prefix[3] == 0))
        {
      XML_PAT_COPY_NSNAME(ctxt, URL, XML_XML_NAMESPACE)
        } else {
      for (i = 0;i < ctxt->nb_namespaces;i++) {
          if (xmlStrEqual(ctxt->namespaces[2 * i + 1], prefix)) {
        XML_PAT_COPY_NSNAME(ctxt, URL, ctxt->namespaces[2 * i])
        break;
          }
      }
      if (i >= ctxt->nb_namespaces) {
          ERROR5(NULL, NULL, NULL,
        "xmlCompileStepPattern : no namespace bound "
        "to prefix %s\n", prefix);
          ctxt->error = 1;
          goto error;
      }
        }
        XML_PAT_FREE_STRING(ctxt, prefix);
        name = NULL;
        if (token == NULL) {
      if (CUR == '*') {
          NEXT;
          PUSH(XML_OP_NS, URL, NULL);
      } else {
          ERROR(NULL, NULL, NULL,
        "xmlCompileStepPattern : Name expected\n");
          ctxt->error = 1;
          goto error;
      }
        } else {
      PUSH(XML_OP_CHILD, token, URL);
        }
    } else
        PUSH(XML_OP_CHILD, name, NULL);
    return;
      } else if (xmlStrEqual(name, (const xmlChar *) "attribute")) {
    XML_PAT_FREE_STRING(ctxt, name)
    name = NULL;
    if (XML_STREAM_XS_IDC_SEL(ctxt->comp)) {
        ERROR5(NULL, NULL, NULL,
      "Unexpected attribute axis in '%s'.\n", ctxt->base);
        ctxt->error = 1;
        goto error;
    }
    xmlCompileAttributeTest(ctxt);
    if (ctxt->error != 0)
        goto error;
    return;
      } else {
    ERROR5(NULL, NULL, NULL,
        "The 'element' or 'attribute' axis is expected.\n", NULL);
    ctxt->error = 1;
    goto error;
      }
  }
    } else if (CUR == '*') {
        if (name != NULL) {
      ctxt->error = 1;
      goto error;
  }
  NEXT;
  PUSH(XML_OP_ALL, token, NULL);
    } else {
  PUSH(XML_OP_ELEM, name, NULL);
    }
    return;
error:
    if (URL != NULL)
  XML_PAT_FREE_STRING(ctxt, URL)
    if (token != NULL)
  XML_PAT_FREE_STRING(ctxt, token)
    if (name != NULL)
  XML_PAT_FREE_STRING(ctxt, name)
}

/**
 * xmlCompilePathPattern:
 * @ctxt:  the compilation context
 *
 * Compile the Path Pattern and generates a precompiled
 * form suitable for fast matching.
 *
 * [5]    Path    ::=    ('.//')? ( Step '/' )* ( Step | '@' NameTest )
 */
static void
xmlCompilePathPattern(xmlPatParserContextPtr ctxt) {
    SKIP_BLANKS;
    if (CUR == '/') {
        ctxt->comp->flags |= PAT_FROM_ROOT;
    } else if ((CUR == '.') || (ctxt->comp->flags & XML_PATTERN_NOTPATTERN)) {
        ctxt->comp->flags |= PAT_FROM_CUR;
    }

    if ((CUR == '/') && (NXT(1) == '/')) {
  PUSH(XML_OP_ANCESTOR, NULL, NULL);
  NEXT;
  NEXT;
    } else if ((CUR == '.') && (NXT(1) == '/') && (NXT(2) == '/')) {
  PUSH(XML_OP_ANCESTOR, NULL, NULL);
  NEXT;
  NEXT;
  NEXT;
  /* Check for incompleteness. */
  SKIP_BLANKS;
  if (CUR == 0) {
      ERROR5(NULL, NULL, NULL,
         "Incomplete expression '%s'.\n", ctxt->base);
      ctxt->error = 1;
      goto error;
  }
    }
    if (CUR == '@') {
  NEXT;
  xmlCompileAttributeTest(ctxt);
        if (ctxt->error != 0)
            goto error;
  SKIP_BLANKS;
  /* TODO: check for incompleteness */
  if (CUR != 0) {
      xmlCompileStepPattern(ctxt);
      if (ctxt->error != 0)
    goto error;
  }
    } else {
        if (CUR == '/') {
      PUSH(XML_OP_ROOT, NULL, NULL);
      NEXT;
      /* Check for incompleteness. */
      SKIP_BLANKS;
      if (CUR == 0) {
    ERROR5(NULL, NULL, NULL,
        "Incomplete expression '%s'.\n", ctxt->base);
    ctxt->error = 1;
    goto error;
      }
  }
  xmlCompileStepPattern(ctxt);
  if (ctxt->error != 0)
      goto error;
  SKIP_BLANKS;
  while (CUR == '/') {
      if (NXT(1) == '/') {
          PUSH(XML_OP_ANCESTOR, NULL, NULL);
    NEXT;
    NEXT;
    SKIP_BLANKS;
    xmlCompileStepPattern(ctxt);
    if (ctxt->error != 0)
        goto error;
      } else {
          PUSH(XML_OP_PARENT, NULL, NULL);
    NEXT;
    SKIP_BLANKS;
    if (CUR == 0) {
        ERROR5(NULL, NULL, NULL,
        "Incomplete expression '%s'.\n", ctxt->base);
        ctxt->error = 1;
        goto error;
    }
    xmlCompileStepPattern(ctxt);
    if (ctxt->error != 0)
        goto error;
      }
  }
    }
    if (CUR != 0) {
  ERROR5(NULL, NULL, NULL,
         "Failed to compile pattern %s\n", ctxt->base);
  ctxt->error = 1;
    }
error:
    return;
}

/**
 * xmlCompileIDCXPathPath:
 * @ctxt:  the compilation context
 *
 * Compile the Path Pattern and generates a precompiled
 * form suitable for fast matching.
 *
 * [5]    Path    ::=    ('.//')? ( Step '/' )* ( Step | '@' NameTest )
 */
static void
xmlCompileIDCXPathPath(xmlPatParserContextPtr ctxt) {
    SKIP_BLANKS;
    if (CUR == '/') {
  ERROR5(NULL, NULL, NULL,
      "Unexpected selection of the document root in '%s'.\n",
      ctxt->base);
  goto error;
    }
    ctxt->comp->flags |= PAT_FROM_CUR;

    if (CUR == '.') {
  /* "." - "self::node()" */
  NEXT;
  SKIP_BLANKS;
  if (CUR == 0) {
      /*
      * Selection of the context node.
      */
      PUSH(XML_OP_ELEM, NULL, NULL);
      return;
  }
  if (CUR != '/') {
      /* TODO: A more meaningful error message. */
      ERROR5(NULL, NULL, NULL,
      "Unexpected token after '.' in '%s'.\n", ctxt->base);
      goto error;
  }
  /* "./" - "self::node()/" */
  NEXT;
  SKIP_BLANKS;
  if (CUR == '/') {
      if (IS_BLANK_CH(PEEKPREV(1))) {
    /*
    * Disallow "./ /"
    */
    ERROR5(NULL, NULL, NULL,
        "Unexpected '/' token in '%s'.\n", ctxt->base);
    goto error;
      }
      /* ".//" - "self:node()/descendant-or-self::node()/" */
      PUSH(XML_OP_ANCESTOR, NULL, NULL);
      NEXT;
      SKIP_BLANKS;
  }
  if (CUR == 0)
      goto error_unfinished;
    }
    /*
    * Process steps.
    */
    do {
  xmlCompileStepPattern(ctxt);
  if (ctxt->error != 0)
      goto error;
  SKIP_BLANKS;
  if (CUR != '/')
      break;
  PUSH(XML_OP_PARENT, NULL, NULL);
  NEXT;
  SKIP_BLANKS;
  if (CUR == '/') {
      /*
      * Disallow subsequent '//'.
      */
      ERROR5(NULL, NULL, NULL,
    "Unexpected subsequent '//' in '%s'.\n",
    ctxt->base);
      goto error;
  }
  if (CUR == 0)
      goto error_unfinished;

    } while (CUR != 0);

    if (CUR != 0) {
  ERROR5(NULL, NULL, NULL,
      "Failed to compile expression '%s'.\n", ctxt->base);
  ctxt->error = 1;
    }
    return;
error:
    ctxt->error = 1;
    return;

error_unfinished:
    ctxt->error = 1;
    ERROR5(NULL, NULL, NULL,
  "Unfinished expression '%s'.\n", ctxt->base);
}

/************************************************************************
 *                  *
 *      The streaming code        *
 *                  *
 ************************************************************************/

/**
 * xmlNewStreamComp:
 * @size: the number of expected steps
 *
 * build a new compiled pattern for streaming
 *
 * Returns the new structure or NULL in case of error.
 */
static xmlStreamCompPtr
xmlNewStreamComp(int size) {
    xmlStreamCompPtr cur;

    if (size < 4)
        size  = 4;

    cur = (xmlStreamCompPtr) xmlMalloc(sizeof(xmlStreamComp));
    if (cur == NULL) {
  ERROR(NULL, NULL, NULL,
    "xmlNewStreamComp: malloc failed\n");
  return(NULL);
    }
    memset(cur, 0, sizeof(xmlStreamComp));
    cur->steps = (xmlStreamStepPtr) xmlMalloc(size * sizeof(xmlStreamStep));
    if (cur->steps == NULL) {
  xmlFree(cur);
  ERROR(NULL, NULL, NULL,
        "xmlNewStreamComp: malloc failed\n");
  return(NULL);
    }
    cur->nbStep = 0;
    cur->maxStep = size;
    return(cur);
}

/**
 * xmlFreeStreamComp:
 * @comp: the compiled pattern for streaming
 *
 * Free the compiled pattern for streaming
 */
static void
xmlFreeStreamComp(xmlStreamCompPtr comp) {
    if (comp != NULL) {
        if (comp->steps != NULL)
      xmlFree(comp->steps);
  if (comp->dict != NULL)
      xmlDictFree(comp->dict);
        xmlFree(comp);
    }
}

/**
 * xmlStreamCompAddStep:
 * @comp: the compiled pattern for streaming
 * @name: the first string, the name, or NULL for *
 * @ns: the second step, the namespace name
 * @flags: the flags for that step
 *
 * Add a new step to the compiled pattern
 *
 * Returns -1 in case of error or the step index if successful
 */
static int
xmlStreamCompAddStep(xmlStreamCompPtr comp, const xmlChar *name,
                     const xmlChar *ns, int nodeType, int flags) {
    xmlStreamStepPtr cur;

    if (comp->nbStep >= comp->maxStep) {
  cur = (xmlStreamStepPtr) xmlRealloc(comp->steps,
         comp->maxStep * 2 * sizeof(xmlStreamStep));
  if (cur == NULL) {
      ERROR(NULL, NULL, NULL,
      "xmlNewStreamComp: malloc failed\n");
      return(-1);
  }
  comp->steps = cur;
        comp->maxStep *= 2;
    }
    cur = &comp->steps[comp->nbStep++];
    cur->flags = flags;
    cur->name = name;
    cur->ns = ns;
    cur->nodeType = nodeType;
    return(comp->nbStep - 1);
}

/**
 * xmlStreamCompile:
 * @comp: the precompiled pattern
 *
 * Tries to stream compile a pattern
 *
 * Returns -1 in case of failure and 0 in case of success.
 */
static int
xmlStreamCompile(xmlPatternPtr comp) {
    xmlStreamCompPtr stream;
    int i, s = 0, root = 0, flags = 0, prevs = -1;
    xmlStepOp step;

    if ((comp == NULL) || (comp->steps == NULL))
        return(-1);
    /*
     * special case for .
     */
    if ((comp->nbStep == 1) &&
        (comp->steps[0].op == XML_OP_ELEM) &&
  (comp->steps[0].value == NULL) &&
  (comp->steps[0].value2 == NULL)) {
  stream = xmlNewStreamComp(0);
  if (stream == NULL)
      return(-1);
  /* Note that the stream will have no steps in this case. */
  stream->flags |= XML_STREAM_FINAL_IS_ANY_NODE;
  comp->stream = stream;
  return(0);
    }

    stream = xmlNewStreamComp((comp->nbStep / 2) + 1);
    if (stream == NULL)
        return(-1);
    if (comp->dict != NULL) {
        stream->dict = comp->dict;
  xmlDictReference(stream->dict);
    }

    i = 0;
    if (comp->flags & PAT_FROM_ROOT)
  stream->flags |= XML_STREAM_FROM_ROOT;

    for (;i < comp->nbStep;i++) {
  step = comp->steps[i];
        switch (step.op) {
      case XML_OP_END:
          break;
      case XML_OP_ROOT:
          if (i != 0)
        goto error;
    root = 1;
    break;
      case XML_OP_NS:
    s = xmlStreamCompAddStep(stream, NULL, step.value,
        XML_ELEMENT_NODE, flags);
    if (s < 0)
        goto error;
    prevs = s;
    flags = 0;
    break;
      case XML_OP_ATTR:
    flags |= XML_STREAM_STEP_ATTR;
    prevs = -1;
    s = xmlStreamCompAddStep(stream,
        step.value, step.value2, XML_ATTRIBUTE_NODE, flags);
    flags = 0;
    if (s < 0)
        goto error;
    break;
      case XML_OP_ELEM:
          if ((step.value == NULL) && (step.value2 == NULL)) {
        /*
        * We have a "." or "self::node()" here.
        * Eliminate redundant self::node() tests like in "/./."
        * or "//./"
        * The only case we won't eliminate is "//.", i.e. if
        * self::node() is the last node test and we had
        * continuation somewhere beforehand.
        */
        if ((comp->nbStep == i + 1) &&
      (flags & XML_STREAM_STEP_DESC)) {
      /*
      * Mark the special case where the expression resolves
      * to any type of node.
      */
      if (comp->nbStep == i + 1) {
          stream->flags |= XML_STREAM_FINAL_IS_ANY_NODE;
      }
      flags |= XML_STREAM_STEP_NODE;
      s = xmlStreamCompAddStep(stream, NULL, NULL,
          XML_STREAM_ANY_NODE, flags);
      if (s < 0)
          goto error;
      flags = 0;
      /*
      * If there was a previous step, mark it to be added to
      * the result node-set; this is needed since only
      * the last step will be marked as "final" and only
      * "final" nodes are added to the resulting set.
      */
      if (prevs != -1) {
          stream->steps[prevs].flags |= XML_STREAM_STEP_IN_SET;
          prevs = -1;
      }
      break;

        } else {
      /* Just skip this one. */
      continue;
        }
    }
    /* An element node. */
          s = xmlStreamCompAddStep(stream, step.value, step.value2,
        XML_ELEMENT_NODE, flags);
    if (s < 0)
        goto error;
    prevs = s;
    flags = 0;
    break;
      case XML_OP_CHILD:
    /* An element node child. */
          s = xmlStreamCompAddStep(stream, step.value, step.value2,
        XML_ELEMENT_NODE, flags);
    if (s < 0)
        goto error;
    prevs = s;
    flags = 0;
    break;
      case XML_OP_ALL:
          s = xmlStreamCompAddStep(stream, NULL, NULL,
        XML_ELEMENT_NODE, flags);
    if (s < 0)
        goto error;
    prevs = s;
    flags = 0;
    break;
      case XML_OP_PARENT:
          break;
      case XML_OP_ANCESTOR:
    /* Skip redundant continuations. */
    if (flags & XML_STREAM_STEP_DESC)
        break;
          flags |= XML_STREAM_STEP_DESC;
    /*
    * Mark the expression as having "//".
    */
    if ((stream->flags & XML_STREAM_DESC) == 0)
        stream->flags |= XML_STREAM_DESC;
    break;
  }
    }
    if ((! root) && (comp->flags & XML_PATTERN_NOTPATTERN) == 0) {
  /*
  * If this should behave like a real pattern, we will mark
  * the first step as having "//", to be reentrant on every
  * tree level.
  */
  if ((stream->flags & XML_STREAM_DESC) == 0)
      stream->flags |= XML_STREAM_DESC;

  if (stream->nbStep > 0) {
      if ((stream->steps[0].flags & XML_STREAM_STEP_DESC) == 0)
    stream->steps[0].flags |= XML_STREAM_STEP_DESC;
  }
    }
    if (stream->nbStep <= s)
  goto error;
    stream->steps[s].flags |= XML_STREAM_STEP_FINAL;
    if (root)
  stream->steps[0].flags |= XML_STREAM_STEP_ROOT;
    comp->stream = stream;
    return(0);
error:
    xmlFreeStreamComp(stream);
    return(0);
}

/**
 * xmlNewStreamCtxt:
 * @size: the number of expected states
 *
 * build a new stream context
 *
 * Returns the new structure or NULL in case of error.
 */
static xmlStreamCtxtPtr
xmlNewStreamCtxt(xmlStreamCompPtr stream) {
    xmlStreamCtxtPtr cur;

    cur = (xmlStreamCtxtPtr) xmlMalloc(sizeof(xmlStreamCtxt));
    if (cur == NULL) {
  ERROR(NULL, NULL, NULL,
    "xmlNewStreamCtxt: malloc failed\n");
  return(NULL);
    }
    memset(cur, 0, sizeof(xmlStreamCtxt));
    cur->states = (int *) xmlMalloc(4 * 2 * sizeof(int));
    if (cur->states == NULL) {
  xmlFree(cur);
  ERROR(NULL, NULL, NULL,
        "xmlNewStreamCtxt: malloc failed\n");
  return(NULL);
    }
    cur->nbState = 0;
    cur->maxState = 4;
    cur->level = 0;
    cur->comp = stream;
    cur->blockLevel = -1;
    return(cur);
}

/**
 * xmlFreeStreamCtxt:
 * @stream: the stream context
 *
 * Free the stream context
 */
void
xmlFreeStreamCtxt(xmlStreamCtxtPtr stream) {
    xmlStreamCtxtPtr next;

    while (stream != NULL) {
        next = stream->next;
        if (stream->states != NULL)
      xmlFree(stream->states);
        xmlFree(stream);
  stream = next;
    }
}

/**
 * xmlStreamCtxtAddState:
 * @comp: the stream context
 * @idx: the step index for that streaming state
 *
 * Add a new state to the stream context
 *
 * Returns -1 in case of error or the state index if successful
 */
static int
xmlStreamCtxtAddState(xmlStreamCtxtPtr comp, int idx, int level) {
    int i;
    for (i = 0;i < comp->nbState;i++) {
        if (comp->states[2 * i] < 0) {
      comp->states[2 * i] = idx;
      comp->states[2 * i + 1] = level;
      return(i);
  }
    }
    if (comp->nbState >= comp->maxState) {
        int *cur;

  cur = (int *) xmlRealloc(comp->states,
         comp->maxState * 4 * sizeof(int));
  if (cur == NULL) {
      ERROR(NULL, NULL, NULL,
      "xmlNewStreamCtxt: malloc failed\n");
      return(-1);
  }
  comp->states = cur;
        comp->maxState *= 2;
    }
    comp->states[2 * comp->nbState] = idx;
    comp->states[2 * comp->nbState++ + 1] = level;
    return(comp->nbState - 1);
}

/**
 * xmlStreamPushInternal:
 * @stream: the stream context
 * @name: the current name
 * @ns: the namespace name
 * @nodeType: the type of the node
 *
 * Push new data onto the stream. NOTE: if the call xmlPatterncompile()
 * indicated a dictionary, then strings for name and ns will be expected
 * to come from the dictionary.
 * Both @name and @ns being NULL means the / i.e. the root of the document.
 * This can also act as a reset.
 *
 * Returns: -1 in case of error, 1 if the current state in the stream is a
 *    match and 0 otherwise.
 */
static int
xmlStreamPushInternal(xmlStreamCtxtPtr stream,
          const xmlChar *name, const xmlChar *ns,
          int nodeType) {
    int ret = 0, final = 0, tmp, i, m, match, stepNr, desc;
    xmlStreamCompPtr comp;
    xmlStreamStep step;

    if ((stream == NULL) || (stream->nbState < 0))
        return(-1);

    while (stream != NULL) {
  comp = stream->comp;

  if ((nodeType == XML_ELEMENT_NODE) &&
      (name == NULL) && (ns == NULL)) {
      /* We have a document node here (or a reset). */
      stream->nbState = 0;
      stream->level = 0;
      stream->blockLevel = -1;
      if (comp->flags & XML_STREAM_FROM_ROOT) {
    if (comp->nbStep == 0) {
        /* TODO: We have a "/." here? */
        ret = 1;
    } else {
        if ((comp->nbStep == 1) &&
      (comp->steps[0].nodeType == XML_STREAM_ANY_NODE) &&
      (comp->steps[0].flags & XML_STREAM_STEP_DESC))
        {
      /*
      * In the case of "//." the document node will match
      * as well.
      */
      ret = 1;
        } else if (comp->steps[0].flags & XML_STREAM_STEP_ROOT) {
      if (xmlStreamCtxtAddState(stream, 0, 0) < 0)
                            return(-1);
        }
    }
      }
      stream = stream->next;
      continue; /* while */
  }

  /*
  * Fast check for ".".
  */
  if (comp->nbStep == 0) {
      /*
       * / and . are handled at the XPath node set creation
       * level by checking min depth
       */
      if (stream->flags & XML_PATTERN_XPATH) {
    stream = stream->next;
    continue; /* while */
      }
      /*
      * For non-pattern like evaluation like XML Schema IDCs
      * or traditional XPath expressions, this will match if
      * we are at the first level only, otherwise on every level.
      */
      if ((nodeType != XML_ATTRIBUTE_NODE) &&
    (((stream->flags & XML_PATTERN_NOTPATTERN) == 0) ||
    (stream->level == 0))) {
        ret = 1;
      }
      stream->level++;
      goto stream_next;
  }
  if (stream->blockLevel != -1) {
      /*
      * Skip blocked expressions.
      */
      stream->level++;
      goto stream_next;
  }

  if ((nodeType != XML_ELEMENT_NODE) &&
      (nodeType != XML_ATTRIBUTE_NODE) &&
      ((comp->flags & XML_STREAM_FINAL_IS_ANY_NODE) == 0)) {
      /*
      * No need to process nodes of other types if we don't
      * resolve to those types.
      * TODO: Do we need to block the context here?
      */
      stream->level++;
      goto stream_next;
  }

  /*
   * Check evolution of existing states
   */
  i = 0;
  m = stream->nbState;
  while (i < m) {
      if ((comp->flags & XML_STREAM_DESC) == 0) {
    /*
    * If there is no "//", then only the last
    * added state is of interest.
    */
    stepNr = stream->states[2 * (stream->nbState -1)];
    /*
    * TODO: Security check, should not happen, remove it.
    */
    if (stream->states[(2 * (stream->nbState -1)) + 1] <
        stream->level) {
        return (-1);
    }
    desc = 0;
    /* loop-stopper */
    i = m;
      } else {
    /*
    * If there are "//", then we need to process every "//"
    * occurring in the states, plus any other state for this
    * level.
    */
    stepNr = stream->states[2 * i];

    /* TODO: should not happen anymore: dead states */
    if (stepNr < 0)
        goto next_state;

    tmp = stream->states[(2 * i) + 1];

    /* skip new states just added */
    if (tmp > stream->level)
        goto next_state;

    /* skip states at ancestor levels, except if "//" */
    desc = comp->steps[stepNr].flags & XML_STREAM_STEP_DESC;
    if ((tmp < stream->level) && (!desc))
        goto next_state;
      }
      /*
      * Check for correct node-type.
      */
      step = comp->steps[stepNr];
      if (step.nodeType != nodeType) {
    if (step.nodeType == XML_ATTRIBUTE_NODE) {
        /*
        * Block this expression for deeper evaluation.
        */
        if ((comp->flags & XML_STREAM_DESC) == 0)
      stream->blockLevel = stream->level +1;
        goto next_state;
    } else if (step.nodeType != XML_STREAM_ANY_NODE)
        goto next_state;
      }
      /*
      * Compare local/namespace-name.
      */
      match = 0;
      if (step.nodeType == XML_STREAM_ANY_NODE) {
    match = 1;
      } else if (step.name == NULL) {
    if (step.ns == NULL) {
        /*
        * This lets through all elements/attributes.
        */
        match = 1;
    } else if (ns != NULL)
        match = xmlStrEqual(step.ns, ns);
      } else if (((step.ns != NULL) == (ns != NULL)) &&
    (name != NULL) &&
    (step.name[0] == name[0]) &&
    xmlStrEqual(step.name, name) &&
    ((step.ns == ns) || xmlStrEqual(step.ns, ns)))
      {
    match = 1;
      }
      if (match) {
    final = step.flags & XML_STREAM_STEP_FINAL;
                if (final) {
                    ret = 1;
                } else if (xmlStreamCtxtAddState(stream, stepNr + 1,
                                                 stream->level + 1) < 0) {
                    return(-1);
                }
    if ((ret != 1) && (step.flags & XML_STREAM_STEP_IN_SET)) {
        /*
        * Check if we have a special case like "foo/bar//.", where
        * "foo" is selected as well.
        */
        ret = 1;
    }
      }
      if (((comp->flags & XML_STREAM_DESC) == 0) &&
    ((! match) || final))  {
    /*
    * Mark this expression as blocked for any evaluation at
    * deeper levels. Note that this includes "/foo"
    * expressions if the *pattern* behaviour is used.
    */
    stream->blockLevel = stream->level +1;
      }
next_state:
      i++;
  }

  stream->level++;

  /*
  * Re/enter the expression.
  * Don't reenter if it's an absolute expression like "/foo",
  *   except "//foo".
  */
  step = comp->steps[0];
  if (step.flags & XML_STREAM_STEP_ROOT)
      goto stream_next;

  desc = step.flags & XML_STREAM_STEP_DESC;
  if (stream->flags & XML_PATTERN_NOTPATTERN) {
      /*
      * Re/enter the expression if it is a "descendant" one,
      * or if we are at the 1st level of evaluation.
      */

      if (stream->level == 1) {
    if (XML_STREAM_XS_IDC(stream)) {
        /*
        * XS-IDC: The missing "self::node()" will always
        * match the first given node.
        */
        goto stream_next;
    } else
        goto compare;
      }
      /*
      * A "//" is always reentrant.
      */
      if (desc)
    goto compare;

      /*
      * XS-IDC: Process the 2nd level, since the missing
      * "self::node()" is responsible for the 2nd level being
      * the real start level.
      */
      if ((stream->level == 2) && XML_STREAM_XS_IDC(stream))
    goto compare;

      goto stream_next;
  }

compare:
  /*
  * Check expected node-type.
  */
  if (step.nodeType != nodeType) {
      if (nodeType == XML_ATTRIBUTE_NODE)
    goto stream_next;
      else if (step.nodeType != XML_STREAM_ANY_NODE)
    goto stream_next;
  }
  /*
  * Compare local/namespace-name.
  */
  match = 0;
  if (step.nodeType == XML_STREAM_ANY_NODE) {
      match = 1;
  } else if (step.name == NULL) {
      if (step.ns == NULL) {
    /*
    * This lets through all elements/attributes.
    */
    match = 1;
      } else if (ns != NULL)
    match = xmlStrEqual(step.ns, ns);
  } else if (((step.ns != NULL) == (ns != NULL)) &&
      (name != NULL) &&
      (step.name[0] == name[0]) &&
      xmlStrEqual(step.name, name) &&
      ((step.ns == ns) || xmlStrEqual(step.ns, ns)))
  {
      match = 1;
  }
  final = step.flags & XML_STREAM_STEP_FINAL;
  if (match) {
      if (final) {
    ret = 1;
            } else if (xmlStreamCtxtAddState(stream, 1, stream->level) < 0) {
                return(-1);
            }
      if ((ret != 1) && (step.flags & XML_STREAM_STEP_IN_SET)) {
    /*
    * Check if we have a special case like "foo//.", where
    * "foo" is selected as well.
    */
    ret = 1;
      }
  }
  if (((comp->flags & XML_STREAM_DESC) == 0) &&
      ((! match) || final))  {
      /*
      * Mark this expression as blocked for any evaluation at
      * deeper levels.
      */
      stream->blockLevel = stream->level;
  }

stream_next:
        stream = stream->next;
    } /* while stream != NULL */

    return(ret);
}

/**
 * xmlStreamPush:
 * @stream: the stream context
 * @name: the current name
 * @ns: the namespace name
 *
 * Push new data onto the stream. NOTE: if the call xmlPatterncompile()
 * indicated a dictionary, then strings for name and ns will be expected
 * to come from the dictionary.
 * Both @name and @ns being NULL means the / i.e. the root of the document.
 * This can also act as a reset.
 * Otherwise the function will act as if it has been given an element-node.
 *
 * Returns: -1 in case of error, 1 if the current state in the stream is a
 *    match and 0 otherwise.
 */
int
xmlStreamPush(xmlStreamCtxtPtr stream,
              const xmlChar *name, const xmlChar *ns) {
    return (xmlStreamPushInternal(stream, name, ns, XML_ELEMENT_NODE));
}

/**
 * xmlStreamPushNode:
 * @stream: the stream context
 * @name: the current name
 * @ns: the namespace name
 * @nodeType: the type of the node being pushed
 *
 * Push new data onto the stream. NOTE: if the call xmlPatterncompile()
 * indicated a dictionary, then strings for name and ns will be expected
 * to come from the dictionary.
 * Both @name and @ns being NULL means the / i.e. the root of the document.
 * This can also act as a reset.
 * Different from xmlStreamPush() this function can be fed with nodes of type:
 * element-, attribute-, text-, cdata-section-, comment- and
 * processing-instruction-node.
 *
 * Returns: -1 in case of error, 1 if the current state in the stream is a
 *    match and 0 otherwise.
 */
int
xmlStreamPushNode(xmlStreamCtxtPtr stream,
      const xmlChar *name, const xmlChar *ns,
      int nodeType)
{
    return (xmlStreamPushInternal(stream, name, ns,
  nodeType));
}

/**
* xmlStreamPushAttr:
* @stream: the stream context
* @name: the current name
* @ns: the namespace name
*
* Push new attribute data onto the stream. NOTE: if the call xmlPatterncompile()
* indicated a dictionary, then strings for name and ns will be expected
* to come from the dictionary.
* Both @name and @ns being NULL means the / i.e. the root of the document.
* This can also act as a reset.
* Otherwise the function will act as if it has been given an attribute-node.
*
* Returns: -1 in case of error, 1 if the current state in the stream is a
*    match and 0 otherwise.
*/
int
xmlStreamPushAttr(xmlStreamCtxtPtr stream,
      const xmlChar *name, const xmlChar *ns) {
    return (xmlStreamPushInternal(stream, name, ns, XML_ATTRIBUTE_NODE));
}

/**
 * xmlStreamPop:
 * @stream: the stream context
 *
 * push one level from the stream.
 *
 * Returns: -1 in case of error, 0 otherwise.
 */
int
xmlStreamPop(xmlStreamCtxtPtr stream) {
    int i, lev;

    if (stream == NULL)
        return(-1);
    while (stream != NULL) {
  /*
  * Reset block-level.
  */
  if (stream->blockLevel == stream->level)
      stream->blockLevel = -1;

  /*
   *  stream->level can be zero when XML_FINAL_IS_ANY_NODE is set
   *  (see the thread at
   *  http://mail.gnome.org/archives/xslt/2008-July/msg00027.html)
   */
  if (stream->level)
      stream->level--;
  /*
   * Check evolution of existing states
   */
  for (i = stream->nbState -1; i >= 0; i--) {
      /* discard obsoleted states */
      lev = stream->states[(2 * i) + 1];
      if (lev > stream->level)
    stream->nbState--;
      if (lev <= stream->level)
    break;
  }
  stream = stream->next;
    }
    return(0);
}

/**
 * xmlStreamWantsAnyNode:
 * @streamCtxt: the stream context
 *
 * Query if the streaming pattern additionally needs to be fed with
 * text-, cdata-section-, comment- and processing-instruction-nodes.
 * If the result is 0 then only element-nodes and attribute-nodes
 * need to be pushed.
 *
 * Returns: 1 in case of need of nodes of the above described types,
 *          0 otherwise. -1 on API errors.
 */
int
xmlStreamWantsAnyNode(xmlStreamCtxtPtr streamCtxt)
{
    if (streamCtxt == NULL)
  return(-1);
    while (streamCtxt != NULL) {
  if (streamCtxt->comp->flags & XML_STREAM_FINAL_IS_ANY_NODE)
      return(1);
  streamCtxt = streamCtxt->next;
    }
    return(0);
}

/************************************************************************
 *                  *
 *      The public interfaces       *
 *                  *
 ************************************************************************/

/**
 * xmlPatternCompileSafe:
 * @pattern: the pattern to compile
 * @dict: an optional dictionary for interned strings
 * @flags: compilation flags, see xmlPatternFlags
 * @namespaces: the prefix definitions, array of [URI, prefix] or NULL
 * @patternOut: output pattern
 *
 * Compile a pattern.
 *
 * Available since 2.13.0.
 *
 * Returns 0 on success, 1 on error, -1 if a memory allocation failed.
 */
int
xmlPatternCompileSafe(const xmlChar *pattern, xmlDict *dict, int flags,
                      const xmlChar **namespaces, xmlPatternPtr *patternOut) {
    xmlPatternPtr ret = NULL, cur;
    xmlPatParserContextPtr ctxt = NULL;
    const xmlChar *or, *start;
    xmlChar *tmp = NULL;
    int type = 0;
    int streamable = 1;
    int error;

    if (patternOut == NULL)
        return(1);

    if (pattern == NULL) {
        error = 1;
        goto error;
    }

    start = pattern;
    or = start;
    while (*or != 0) {
  tmp = NULL;
  while ((*or != 0) && (*or != '|')) or++;
        if (*or == 0)
      ctxt = xmlNewPatParserContext(start, dict, namespaces);
  else {
      tmp = xmlStrndup(start, or - start);
      if (tmp != NULL) {
    ctxt = xmlNewPatParserContext(tmp, dict, namespaces);
      }
      or++;
  }
  if (ctxt == NULL) {
            error = -1;
            goto error;
        }
  cur = xmlNewPattern();
  if (cur == NULL) {
            error = -1;
            goto error;
        }
  /*
  * Assign string dict.
  */
  if (dict) {
      cur->dict = dict;
      xmlDictReference(dict);
  }
  if (ret == NULL)
      ret = cur;
  else {
      cur->next = ret->next;
      ret->next = cur;
  }
  cur->flags = flags;
  ctxt->comp = cur;

  if (XML_STREAM_XS_IDC(cur))
      xmlCompileIDCXPathPath(ctxt);
  else
      xmlCompilePathPattern(ctxt);
  if (ctxt->error != 0) {
            error = ctxt->error;
      goto error;
        }
  xmlFreePatParserContext(ctxt);
  ctxt = NULL;


        if (streamable) {
      if (type == 0) {
          type = cur->flags & (PAT_FROM_ROOT | PAT_FROM_CUR);
      } else if (type == PAT_FROM_ROOT) {
          if (cur->flags & PAT_FROM_CUR)
        streamable = 0;
      } else if (type == PAT_FROM_CUR) {
          if (cur->flags & PAT_FROM_ROOT)
        streamable = 0;
      }
  }
  if (streamable) {
      error = xmlStreamCompile(cur);
            if (error != 0)
                goto error;
        }
  error = xmlReversePattern(cur);
        if (error != 0)
      goto error;
  if (tmp != NULL) {
      xmlFree(tmp);
      tmp = NULL;
  }
  start = or;
    }
    if (streamable == 0) {
        cur = ret;
  while (cur != NULL) {
      if (cur->stream != NULL) {
    xmlFreeStreamComp(cur->stream);
    cur->stream = NULL;
      }
      cur = cur->next;
  }
    }

    *patternOut = ret;
    return(0);
error:
    if (ctxt != NULL) xmlFreePatParserContext(ctxt);
    if (ret != NULL) xmlFreePattern(ret);
    if (tmp != NULL) xmlFree(tmp);
    *patternOut = NULL;
    return(error);
}

/**
 * xmlPatterncompile:
 * @pattern: the pattern to compile
 * @dict: an optional dictionary for interned strings
 * @flags: compilation flags, see xmlPatternFlags
 * @namespaces: the prefix definitions, array of [URI, prefix] or NULL
 *
 * Compile a pattern.
 *
 * Returns the compiled form of the pattern or NULL in case of error
 */
xmlPatternPtr
xmlPatterncompile(const xmlChar *pattern, xmlDict *dict, int flags,
                  const xmlChar **namespaces) {
    xmlPatternPtr ret;
    xmlPatternCompileSafe(pattern, dict, flags, namespaces, &ret);
    return(ret);
}

/**
 * xmlPatternMatch:
 * @comp: the precompiled pattern
 * @node: a node
 *
 * Test whether the node matches the pattern
 *
 * Returns 1 if it matches, 0 if it doesn't and -1 in case of failure
 */
int
xmlPatternMatch(xmlPatternPtr comp, xmlNodePtr node)
{
    int ret = 0;

    if ((comp == NULL) || (node == NULL))
        return(-1);

    while (comp != NULL) {
        ret = xmlPatMatch(comp, node);
  if (ret != 0)
      return(ret);
  comp = comp->next;
    }
    return(ret);
}

/**
 * xmlPatternGetStreamCtxt:
 * @comp: the precompiled pattern
 *
 * Get a streaming context for that pattern
 * Use xmlFreeStreamCtxt to free the context.
 *
 * Returns a pointer to the context or NULL in case of failure
 */
xmlStreamCtxtPtr
xmlPatternGetStreamCtxt(xmlPatternPtr comp)
{
    xmlStreamCtxtPtr ret = NULL, cur;

    if ((comp == NULL) || (comp->stream == NULL))
        return(NULL);

    while (comp != NULL) {
        if (comp->stream == NULL)
      goto failed;
  cur = xmlNewStreamCtxt(comp->stream);
  if (cur == NULL)
      goto failed;
  if (ret == NULL)
      ret = cur;
  else {
      cur->next = ret->next;
      ret->next = cur;
  }
  cur->flags = comp->flags;
  comp = comp->next;
    }
    return(ret);
failed:
    xmlFreeStreamCtxt(ret);
    return(NULL);
}

/**
 * xmlPatternStreamable:
 * @comp: the precompiled pattern
 *
 * Check if the pattern is streamable i.e. xmlPatternGetStreamCtxt()
 * should work.
 *
 * Returns 1 if streamable, 0 if not and -1 in case of error.
 */
int
xmlPatternStreamable(xmlPatternPtr comp) {
    if (comp == NULL)
        return(-1);
    while (comp != NULL) {
        if (comp->stream == NULL)
      return(0);
  comp = comp->next;
    }
    return(1);
}

/**
 * xmlPatternMaxDepth:
 * @comp: the precompiled pattern
 *
 * Check the maximum depth reachable by a pattern
 *
 * Returns -2 if no limit (using //), otherwise the depth,
 *         and -1 in case of error
 */
int
xmlPatternMaxDepth(xmlPatternPtr comp) {
    int ret = 0, i;
    if (comp == NULL)
        return(-1);
    while (comp != NULL) {
        if (comp->stream == NULL)
      return(-1);
  for (i = 0;i < comp->stream->nbStep;i++)
      if (comp->stream->steps[i].flags & XML_STREAM_STEP_DESC)
          return(-2);
  if (comp->stream->nbStep > ret)
      ret = comp->stream->nbStep;
  comp = comp->next;
    }
    return(ret);
}

/**
 * xmlPatternMinDepth:
 * @comp: the precompiled pattern
 *
 * Check the minimum depth reachable by a pattern, 0 mean the / or . are
 * part of the set.
 *
 * Returns -1 in case of error otherwise the depth,
 *
 */
int
xmlPatternMinDepth(xmlPatternPtr comp) {
    int ret = 12345678;
    if (comp == NULL)
        return(-1);
    while (comp != NULL) {
        if (comp->stream == NULL)
      return(-1);
  if (comp->stream->nbStep < ret)
      ret = comp->stream->nbStep;
  if (ret == 0)
      return(0);
  comp = comp->next;
    }
    return(ret);
}

/**
 * xmlPatternFromRoot:
 * @comp: the precompiled pattern
 *
 * Check if the pattern must be looked at from the root.
 *
 * Returns 1 if true, 0 if false and -1 in case of error
 */
int
xmlPatternFromRoot(xmlPatternPtr comp) {
    if (comp == NULL)
        return(-1);
    while (comp != NULL) {
        if (comp->stream == NULL)
      return(-1);
  if (comp->flags & PAT_FROM_ROOT)
      return(1);
  comp = comp->next;
    }
    return(0);

}

#endif /* LIBXML_PATTERN_ENABLED */

Coverage Report

Created: 2024-09-06 07:53