source: vbox/trunk/src/libs/libxml2-2.13.2/pattern.c@ 105589

/*
 * 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);
}

#if 0
/**
 * xsltSwapTopPattern:
 * @comp:  the compiled match expression
 *
 * reverse the two top steps.
 */
static void
xsltSwapTopPattern(xmlPatternPtr comp) {
    int i;
    int j = comp->nbStep - 1;

    if (j > 0) {
        register const xmlChar *tmp;
        register xmlPatOp op;
        i = j - 1;
        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;
    }
}
#endif

/**
 * 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->states == NULL) || (states->maxstates <= 0)) {
        states->maxstates = 4;
        states->nbstates = 0;
        states->states = xmlMalloc(4 * sizeof(xmlStepState));
    }
    else if (states->maxstates <= states->nbstates) {
        xmlStepState *tmp;

        tmp = (xmlStepStatePtr) xmlRealloc(states->states,
                               2 * states->maxstates * sizeof(xmlStepState));
        if (tmp == NULL)
            return(-1);
        states->states = tmp;
        states->maxstates *= 2;
    }
    states->states[states->nbstates].step = step;
    states->states[states->nbstates++].node = node;
#if 0
    fprintf(stderr, "Push: %d, %s\n", step, node->name);
#endif
    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;
#if 0
    fprintf(stderr, "Pop: %d, %s\n", i, node->name);
#endif
    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;

#if 0
/**
 * xmlPatScanLiteral:
 * @ctxt:  the XPath Parser context
 *
 * Parse an XPath Literal:
 *
 * [29] Literal ::= '"' [^"]* '"'
 *                | "'" [^']* "'"
 *
 * Returns the Literal parsed or NULL
 */

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

    SKIP_BLANKS;
    if (CUR == '"') {
        NEXT;
        cur = q = CUR_PTR;
        val = xmlStringCurrentChar(NULL, cur, &len);
        while ((IS_CHAR(val)) && (val != '"')) {
            cur += len;
            val = xmlStringCurrentChar(NULL, cur, &len);
        }
        if (!IS_CHAR(val)) {
            ctxt->error = 1;
            return(NULL);
        } else {
            if (ctxt->dict)
                ret = (xmlChar *) xmlDictLookup(ctxt->dict, q, cur - q);
            else
                ret = xmlStrndup(q, cur - q);
        }
        cur += len;
        CUR_PTR = cur;
    } else if (CUR == '\'') {
        NEXT;
        cur = q = CUR_PTR;
        val = xmlStringCurrentChar(NULL, cur, &len);
        while ((IS_CHAR(val)) && (val != '\'')) {
            cur += len;
            val = xmlStringCurrentChar(NULL, cur, &len);
        }
        if (!IS_CHAR(val)) {
            ctxt->error = 1;
            return(NULL);
        } else {
            if (ctxt->dict)
                ret = (xmlChar *) xmlDictLookup(ctxt->dict, q, cur - q);
            else
                ret = xmlStrndup(q, cur - q);
        }
        cur += len;
        CUR_PTR = cur;
    } else {
        /* XP_ERROR(XPATH_START_LITERAL_ERROR); */
        ctxt->error = 1;
        return(NULL);
    }
    return(ret);
}
#endif

/**
 * 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);
}

#if 0
/**
 * xmlPatScanQName:
 * @ctxt:  the XPath Parser context
 * @prefix:  the place to store the prefix
 *
 * Parse a qualified name
 *
 * Returns the Name parsed or NULL
 */

static xmlChar *
xmlPatScanQName(xmlPatParserContextPtr ctxt, xmlChar **prefix) {
    xmlChar *ret = NULL;

    *prefix = NULL;
    ret = xmlPatScanNCName(ctxt);
    if (CUR == ':') {
        *prefix = ret;
        NEXT;
        ret = xmlPatScanNCName(ctxt);
    }
    return(ret);
}
#endif

/**
 * 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);
    return;
}

/************************************************************************
 *                                                                      *
 *                      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 0
/*
* TODO: Pointer comparison won't work, since not guaranteed that the given
*  values are in the same dict; especially if it's the namespace name,
*  normally coming from ns->href. We need a namespace dict mechanism !
*/
            } else if (comp->dict) {
                if (step.name == NULL) {
                    if (step.ns == NULL)
                        match = 1;
                    else
                        match = (step.ns == ns);
                } else {
                    match = ((step.name == name) && (step.ns == ns));
                }
#endif /* if 0 ------------------------------------------------------- */
            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 */