valid.c

/*
 * valid.c : part of the code use to do the DTD handling and the validity
 *           checking
 *
 * See Copyright for the status of this software.
 *
 * Daniel.Veillard@w3.org
 */

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

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

#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif

#include <libxml/xmlmemory.h>
#include <libxml/hash.h>
#include <libxml/valid.h>
#include <libxml/parser.h>
#include <libxml/parserInternals.h>
#include <libxml/xmlerror.h>

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

#define PUSH_AND_POP(scope, type, name)					\
scope int name##VPush(xmlValidCtxtPtr ctxt, type value) {		\
    if (ctxt->name##Nr >= ctxt->name##Max) {				\
	ctxt->name##Max *= 2;						\
        ctxt->name##Tab = (type *) xmlRealloc(ctxt->name##Tab,		\
	             ctxt->name##Max * sizeof(ctxt->name##Tab[0]));	\
        if (ctxt->name##Tab == NULL) {					\
	    xmlGenericError(xmlGenericErrorContext,			\
		    "realloc failed !\n");				\
	    return(0);							\
	}								\
    }									\
    ctxt->name##Tab[ctxt->name##Nr] = value;				\
    ctxt->name = value;							\
    return(ctxt->name##Nr++);						\
}									\
scope type name##VPop(xmlValidCtxtPtr ctxt) {				\
    type ret;								\
    if (ctxt->name##Nr <= 0) return(0);					\
    ctxt->name##Nr--;							\
    if (ctxt->name##Nr > 0)						\
	ctxt->name = ctxt->name##Tab[ctxt->name##Nr - 1];		\
    else								\
        ctxt->name = NULL;						\
    ret = ctxt->name##Tab[ctxt->name##Nr];				\
    ctxt->name##Tab[ctxt->name##Nr] = 0;				\
    return(ret);							\
}									\

PUSH_AND_POP(static, xmlNodePtr, node)

/* #define DEBUG_VALID_ALGO */

#ifdef DEBUG_VALID_ALGO
void xmlValidPrintNodeList(xmlNodePtr cur) {
    if (cur == NULL)
	xmlGenericError(xmlGenericErrorContext, "null ");
    while (cur != NULL) {
	switch (cur->type) {
	    case XML_ELEMENT_NODE:
		xmlGenericError(xmlGenericErrorContext, "%s ", cur->name);
		break;
	    case XML_TEXT_NODE:
		xmlGenericError(xmlGenericErrorContext, "text ");
		break;
	    case XML_CDATA_SECTION_NODE:
		xmlGenericError(xmlGenericErrorContext, "cdata ");
		break;
	    case XML_ENTITY_REF_NODE:
		xmlGenericError(xmlGenericErrorContext, "&%s; ", cur->name);
		break;
	    case XML_PI_NODE:
		xmlGenericError(xmlGenericErrorContext, "pi(%s) ", cur->name);
		break;
	    case XML_COMMENT_NODE:
		xmlGenericError(xmlGenericErrorContext, "comment ");
		break;
	    case XML_ATTRIBUTE_NODE:
		xmlGenericError(xmlGenericErrorContext, "?attr? ");
		break;
	    case XML_ENTITY_NODE:
		xmlGenericError(xmlGenericErrorContext, "?ent? ");
		break;
	    case XML_DOCUMENT_NODE:
		xmlGenericError(xmlGenericErrorContext, "?doc? ");
		break;
	    case XML_DOCUMENT_TYPE_NODE:
		xmlGenericError(xmlGenericErrorContext, "?doctype? ");
		break;
	    case XML_DOCUMENT_FRAG_NODE:
		xmlGenericError(xmlGenericErrorContext, "?frag? ");
		break;
	    case XML_NOTATION_NODE:
		xmlGenericError(xmlGenericErrorContext, "?nota? ");
		break;
	    case XML_HTML_DOCUMENT_NODE:
		xmlGenericError(xmlGenericErrorContext, "?html? ");
		break;
	    case XML_DTD_NODE:
		xmlGenericError(xmlGenericErrorContext, "?dtd? ");
		break;
	    case XML_ELEMENT_DECL:
		xmlGenericError(xmlGenericErrorContext, "?edecl? ");
		break;
	    case XML_ATTRIBUTE_DECL:
		xmlGenericError(xmlGenericErrorContext, "?adecl? ");
		break;
	    case XML_ENTITY_DECL:
		xmlGenericError(xmlGenericErrorContext, "?entdecl? ");
		break;
	}
	cur = cur->next;
    }
}

void xmlValidDebug(xmlNodePtr cur, xmlElementContentPtr cont) {
    char expr[1000];

    expr[0] = 0;
    xmlGenericError(xmlGenericErrorContext, "valid: ");
    xmlValidPrintNodeList(cur);
    xmlGenericError(xmlGenericErrorContext, "against ");
    xmlSprintfElementContent(expr, cont, 0);
    xmlGenericError(xmlGenericErrorContext, "%s\n", expr);
}

#define DEBUG_VALID_STATE(n,c) xmlValidDebug(n,c);
#else
#define DEBUG_VALID_STATE(n,c)
#endif

/* TODO: use hash table for accesses to elem and attribute dedinitions */

#define VERROR							\
   if ((ctxt != NULL) && (ctxt->error != NULL)) ctxt->error

#define VWARNING						\
   if ((ctxt != NULL) && (ctxt->warning != NULL)) ctxt->warning

#define CHECK_DTD						\
   if (doc == NULL) return(0);					\
   else if ((doc->intSubset == NULL) &&				\
	    (doc->extSubset == NULL)) return(0)

xmlElementPtr xmlGetDtdElementDesc(xmlDtdPtr dtd, const xmlChar *name);
xmlAttributePtr xmlScanAttributeDecl(xmlDtdPtr dtd, const xmlChar *elem);

/************************************************************************
 *									*
 *			QName handling helper				*
 *									*
 ************************************************************************/

/**
 * xmlSplitQName2:
 * @name:  an XML parser context
 * @prefix:  a xmlChar ** 
 *
 * parse an XML qualified name string
 *
 * [NS 5] QName ::= (Prefix ':')? LocalPart
 *
 * [NS 6] Prefix ::= NCName
 *
 * [NS 7] LocalPart ::= NCName
 *
 * Returns NULL if not a QName, otherwise the local part, and prefix
 *   is updated to get the Prefix if any.
 */

xmlChar *
xmlSplitQName2(const xmlChar *name, xmlChar **prefix) {
    int len = 0;
    xmlChar *ret = NULL;

    *prefix = NULL;

    /* xml: prefix is not really a namespace */
    if ((name[0] == 'x') && (name[1] == 'm') &&
        (name[2] == 'l') && (name[3] == ':'))
	return(NULL);

    /* nasty but valid */
    if (name[0] == ':')
	return(NULL);

    /*
     * we are not trying to validate but just to cut, and yes it will
     * work even if this is as set of UTF-8 encoded chars
     */
    while ((name[len] != 0) && (name[len] != ':')) 
	len++;
    
    if (name[len] == 0)
	return(NULL);

    *prefix = xmlStrndup(name, len);
    ret = xmlStrdup(&name[len + 1]);

    return(ret);
}

/****************************************************************
 *								*
 *	Util functions for data allocation/deallocation		*
 *								*
 ****************************************************************/

/**
 * xmlNewElementContent:
 * @name:  the subelement name or NULL
 * @type:  the type of element content decl
 *
 * Allocate an element content structure.
 *
 * Returns NULL if not, othervise the new element content structure
 */
xmlElementContentPtr
xmlNewElementContent(xmlChar *name, xmlElementContentType type) {
    xmlElementContentPtr ret;

    switch(type) {
	case XML_ELEMENT_CONTENT_ELEMENT:
	    if (name == NULL) {
	        xmlGenericError(xmlGenericErrorContext,
			"xmlNewElementContent : name == NULL !\n");
	    }
	    break;
        case XML_ELEMENT_CONTENT_PCDATA:
	case XML_ELEMENT_CONTENT_SEQ:
	case XML_ELEMENT_CONTENT_OR:
	    if (name != NULL) {
	        xmlGenericError(xmlGenericErrorContext,
			"xmlNewElementContent : name != NULL !\n");
	    }
	    break;
	default:
	    xmlGenericError(xmlGenericErrorContext,
		    "xmlNewElementContent: unknown type %d\n", type);
	    return(NULL);
    }
    ret = (xmlElementContentPtr) xmlMalloc(sizeof(xmlElementContent));
    if (ret == NULL) {
	xmlGenericError(xmlGenericErrorContext,
		"xmlNewElementContent : out of memory!\n");
	return(NULL);
    }
    ret->type = type;
    ret->ocur = XML_ELEMENT_CONTENT_ONCE;
    if (name != NULL)
        ret->name = xmlStrdup(name);
    else
        ret->name = NULL;
    ret->c1 = ret->c2 = NULL;
    return(ret);
}

/**
 * xmlCopyElementContent:
 * @content:  An element content pointer.
 *
 * Build a copy of an element content description.
 * 
 * Returns the new xmlElementContentPtr or NULL in case of error.
 */
xmlElementContentPtr
xmlCopyElementContent(xmlElementContentPtr cur) {
    xmlElementContentPtr ret;

    if (cur == NULL) return(NULL);
    ret = xmlNewElementContent((xmlChar *) cur->name, cur->type);
    if (ret == NULL) {
        xmlGenericError(xmlGenericErrorContext,
		"xmlCopyElementContent : out of memory\n");
	return(NULL);
    }
    ret->ocur = cur->ocur;
    if (cur->c1 != NULL) ret->c1 = xmlCopyElementContent(cur->c1);
    if (cur->c2 != NULL) ret->c2 = xmlCopyElementContent(cur->c2);
    return(ret);
}

/**
 * xmlFreeElementContent:
 * @cur:  the element content tree to free
 *
 * Free an element content structure. This is a recursive call !
 */
void
xmlFreeElementContent(xmlElementContentPtr cur) {
    if (cur == NULL) return;
    switch (cur->type) {
	case XML_ELEMENT_CONTENT_PCDATA:
	case XML_ELEMENT_CONTENT_ELEMENT:
	case XML_ELEMENT_CONTENT_SEQ:
	case XML_ELEMENT_CONTENT_OR:
	    break;
	default:
	    xmlGenericError(xmlGenericErrorContext,
		    "xmlFreeElementContent : type %d\n", cur->type);
	    return;
    }
    if (cur->c1 != NULL) xmlFreeElementContent(cur->c1);
    if (cur->c2 != NULL) xmlFreeElementContent(cur->c2);
    if (cur->name != NULL) xmlFree((xmlChar *) cur->name);
    memset(cur, -1, sizeof(xmlElementContent));
    xmlFree(cur);
}

/**
 * xmlDumpElementContent:
 * @buf:  An XML buffer
 * @content:  An element table
 * @glob: 1 if one must print the englobing parenthesis, 0 otherwise
 *
 * This will dump the content of the element table as an XML DTD definition
 */
void
xmlDumpElementContent(xmlBufferPtr buf, xmlElementContentPtr content, int glob) {
    if (content == NULL) return;

    if (glob) xmlBufferWriteChar(buf, "(");
    switch (content->type) {
        case XML_ELEMENT_CONTENT_PCDATA:
            xmlBufferWriteChar(buf, "#PCDATA");
	    break;
	case XML_ELEMENT_CONTENT_ELEMENT:
	    xmlBufferWriteCHAR(buf, content->name);
	    break;
	case XML_ELEMENT_CONTENT_SEQ:
	    if ((content->c1->type == XML_ELEMENT_CONTENT_OR) ||
	        (content->c1->type == XML_ELEMENT_CONTENT_SEQ))
		xmlDumpElementContent(buf, content->c1, 1);
	    else
		xmlDumpElementContent(buf, content->c1, 0);
            xmlBufferWriteChar(buf, " , ");
	    if (content->c2->type == XML_ELEMENT_CONTENT_OR)
		xmlDumpElementContent(buf, content->c2, 1);
	    else
		xmlDumpElementContent(buf, content->c2, 0);
	    break;
	case XML_ELEMENT_CONTENT_OR:
	    if ((content->c1->type == XML_ELEMENT_CONTENT_OR) ||
	        (content->c1->type == XML_ELEMENT_CONTENT_SEQ))
		xmlDumpElementContent(buf, content->c1, 1);
	    else
		xmlDumpElementContent(buf, content->c1, 0);
            xmlBufferWriteChar(buf, " | ");
	    if (content->c2->type == XML_ELEMENT_CONTENT_SEQ)
		xmlDumpElementContent(buf, content->c2, 1);
	    else
		xmlDumpElementContent(buf, content->c2, 0);
	    break;
	default:
	    xmlGenericError(xmlGenericErrorContext,
		    "xmlDumpElementContent: unknown type %d\n",
	            content->type);
    }
    if (glob)
        xmlBufferWriteChar(buf, ")");
    switch (content->ocur) {
        case XML_ELEMENT_CONTENT_ONCE:
	    break;
        case XML_ELEMENT_CONTENT_OPT:
	    xmlBufferWriteChar(buf, "?");
	    break;
        case XML_ELEMENT_CONTENT_MULT:
	    xmlBufferWriteChar(buf, "*");
	    break;
        case XML_ELEMENT_CONTENT_PLUS:
	    xmlBufferWriteChar(buf, "+");
	    break;
    }
}

/**
 * xmlSprintfElementContent:
 * @buf:  an output buffer
 * @content:  An element table
 * @glob: 1 if one must print the englobing parenthesis, 0 otherwise
 *
 * This will dump the content of the element content definition
 * Intended just for the debug routine
 */
void
xmlSprintfElementContent(char *buf, xmlElementContentPtr content, int glob) {
    if (content == NULL) return;
    if (glob) strcat(buf, "(");
    switch (content->type) {
        case XML_ELEMENT_CONTENT_PCDATA:
            strcat(buf, "#PCDATA");
	    break;
	case XML_ELEMENT_CONTENT_ELEMENT:
	    strcat(buf, (char *) content->name);
	    break;
	case XML_ELEMENT_CONTENT_SEQ:
	    if ((content->c1->type == XML_ELEMENT_CONTENT_OR) ||
	        (content->c1->type == XML_ELEMENT_CONTENT_SEQ))
		xmlSprintfElementContent(buf, content->c1, 1);
	    else
		xmlSprintfElementContent(buf, content->c1, 0);
            strcat(buf, " , ");
	    if (content->c2->type == XML_ELEMENT_CONTENT_OR)
		xmlSprintfElementContent(buf, content->c2, 1);
	    else
		xmlSprintfElementContent(buf, content->c2, 0);
	    break;
	case XML_ELEMENT_CONTENT_OR:
	    if ((content->c1->type == XML_ELEMENT_CONTENT_OR) ||
	        (content->c1->type == XML_ELEMENT_CONTENT_SEQ))
		xmlSprintfElementContent(buf, content->c1, 1);
	    else
		xmlSprintfElementContent(buf, content->c1, 0);
            strcat(buf, " | ");
	    if (content->c2->type == XML_ELEMENT_CONTENT_SEQ)
		xmlSprintfElementContent(buf, content->c2, 1);
	    else
		xmlSprintfElementContent(buf, content->c2, 0);
	    break;
    }
    if (glob)
        strcat(buf, ")");
    switch (content->ocur) {
        case XML_ELEMENT_CONTENT_ONCE:
	    break;
        case XML_ELEMENT_CONTENT_OPT:
	    strcat(buf, "?");
	    break;
        case XML_ELEMENT_CONTENT_MULT:
	    strcat(buf, "*");
	    break;
        case XML_ELEMENT_CONTENT_PLUS:
	    strcat(buf, "+");
	    break;
    }
}

/****************************************************************
 *								*
 *	Registration of DTD declarations			*
 *								*
 ****************************************************************/

/**
 * xmlCreateElementTable:
 *
 * create and initialize an empty element hash table.
 *
 * Returns the xmlElementTablePtr just created or NULL in case of error.
 */
xmlElementTablePtr
xmlCreateElementTable(void) {
    return(xmlHashCreate(0));
}

/**
 * xmlFreeElement:
 * @elem:  An element
 *
 * Deallocate the memory used by an element definition
 */
void
xmlFreeElement(xmlElementPtr elem) {
    if (elem == NULL) return;
    xmlUnlinkNode((xmlNodePtr) elem);
    xmlFreeElementContent(elem->content);
    if (elem->name != NULL)
	xmlFree((xmlChar *) elem->name);
    if (elem->prefix != NULL)
	xmlFree((xmlChar *) elem->prefix);
    memset(elem, -1, sizeof(xmlElement));
    xmlFree(elem);
}


/**
 * xmlAddElementDecl:
 * @ctxt:  the validation context
 * @dtd:  pointer to the DTD
 * @name:  the entity name
 * @type:  the element type
 * @content:  the element content tree or NULL
 *
 * Register a new element declaration
 *
 * Returns NULL if not, othervise the entity
 */
xmlElementPtr
xmlAddElementDecl(xmlValidCtxtPtr ctxt, xmlDtdPtr dtd, const xmlChar *name,
                  xmlElementTypeVal type,
		  xmlElementContentPtr content) {
    xmlElementPtr ret;
    xmlElementTablePtr table;
    xmlChar *ns, *uqname;

    if (dtd == NULL) {
        xmlGenericError(xmlGenericErrorContext,
		"xmlAddElementDecl: dtd == NULL\n");
	return(NULL);
    }
    if (name == NULL) {
        xmlGenericError(xmlGenericErrorContext,
		"xmlAddElementDecl: name == NULL\n");
	return(NULL);
    }
    switch (type) {
        case XML_ELEMENT_TYPE_EMPTY:
	    if (content != NULL) {
	        xmlGenericError(xmlGenericErrorContext,
		        "xmlAddElementDecl: content != NULL for EMPTY\n");
		return(NULL);
	    }
	    break;
	case XML_ELEMENT_TYPE_ANY:
	    if (content != NULL) {
	        xmlGenericError(xmlGenericErrorContext,
		        "xmlAddElementDecl: content != NULL for ANY\n");
		return(NULL);
	    }
	    break;
	case XML_ELEMENT_TYPE_MIXED:
	    if (content == NULL) {
	        xmlGenericError(xmlGenericErrorContext,
		        "xmlAddElementDecl: content == NULL for MIXED\n");
		return(NULL);
	    }
	    break;
	case XML_ELEMENT_TYPE_ELEMENT:
	    if (content == NULL) {
	        xmlGenericError(xmlGenericErrorContext,
		        "xmlAddElementDecl: content == NULL for ELEMENT\n");
		return(NULL);
	    }
	    break;
	default:
	    xmlGenericError(xmlGenericErrorContext,
		    "xmlAddElementDecl: unknown type %d\n", type);
	    return(NULL);
    }

    /*
     * check if name is a QName
     */
    uqname = xmlSplitQName2(name, &ns);
    if (uqname != NULL)
	name = uqname;

    /*
     * Create the Element table if needed.
     */
    table = (xmlElementTablePtr) dtd->elements;
    if (table == NULL) {
        table = xmlCreateElementTable();
	dtd->elements = (void *) table;
    }
    if (table == NULL) {
	xmlGenericError(xmlGenericErrorContext,
		"xmlAddElementDecl: Table creation failed!\n");
        return(NULL);
    }

    ret = (xmlElementPtr) xmlMalloc(sizeof(xmlElement));
    if (ret == NULL) {
	xmlGenericError(xmlGenericErrorContext,
		"xmlAddElementDecl: out of memory\n");
	return(NULL);
    }
    memset(ret, 0, sizeof(xmlElement));
    ret->type = XML_ELEMENT_DECL;

    /*
     * fill the structure.
     */
    ret->etype = type;
    ret->name = xmlStrdup(name);
    ret->prefix = ns;
    ret->content = xmlCopyElementContent(content);
    ret->attributes = xmlScanAttributeDecl(dtd, name);

    /*
     * Validity Check:
     * Insertion must not fail
     */
    if (xmlHashAddEntry2(table, name, ns, ret)) {
	/*
	 * The element is already defined in this Dtd.
	 */
	VERROR(ctxt->userData, "Redefinition of element %s\n", name);
	xmlFreeElement(ret);
	if (uqname != NULL)
	    xmlFree(uqname);
	return(NULL);
    }

    /*
     * Link it to the Dtd
     */
    ret->parent = dtd;
    ret->doc = dtd->doc;
    if (dtd->last == NULL) {
	dtd->children = dtd->last = (xmlNodePtr) ret;
    } else {
        dtd->last->next = (xmlNodePtr) ret;
	ret->prev = dtd->last;
	dtd->last = (xmlNodePtr) ret;
    }
    if (uqname != NULL)
	xmlFree(uqname);
    return(ret);
}

/**
 * xmlFreeElementTable:
 * @table:  An element table
 *
 * Deallocate the memory used by an element hash table.
 */
void
xmlFreeElementTable(xmlElementTablePtr table) {
    xmlHashFree(table, (xmlHashDeallocator) xmlFreeElement);
}

/**
 * xmlCopyElement:
 * @elem:  An element
 *
 * Build a copy of an element.
 * 
 * Returns the new xmlElementPtr or NULL in case of error.
 */
xmlElementPtr
xmlCopyElement(xmlElementPtr elem) {
    xmlElementPtr cur;

    cur = (xmlElementPtr) xmlMalloc(sizeof(xmlElement));
    if (cur == NULL) {
	xmlGenericError(xmlGenericErrorContext,
		"xmlCopyElement: out of memory !\n");
	return(NULL);
    }
    memset(cur, 0, sizeof(xmlElement));
    cur->type = XML_ELEMENT_DECL;
    cur->etype = elem->etype;
    if (elem->name != NULL)
	cur->name = xmlStrdup(elem->name);
    else
	cur->name = NULL;
    if (elem->prefix != NULL)
	cur->prefix = xmlStrdup(elem->prefix);
    else
	cur->prefix = NULL;
    cur->content = xmlCopyElementContent(elem->content);
    /* TODO : rebuild the attribute list on the copy */
    cur->attributes = NULL;
    return(cur);
}

/**
 * xmlCopyElementTable:
 * @table:  An element table
 *
 * Build a copy of an element table.
 * 
 * Returns the new xmlElementTablePtr or NULL in case of error.
 */
xmlElementTablePtr
xmlCopyElementTable(xmlElementTablePtr table) {
    return((xmlElementTablePtr) xmlHashCopy(table,
		                            (xmlHashCopier) xmlCopyElement));
}

/**
 * xmlDumpElementDecl:
 * @buf:  the XML buffer output
 * @elem:  An element table
 *
 * This will dump the content of the element declaration as an XML
 * DTD definition
 */
void
xmlDumpElementDecl(xmlBufferPtr buf, xmlElementPtr elem) {
    switch (elem->etype) {
	case XML_ELEMENT_TYPE_EMPTY:
	    xmlBufferWriteChar(buf, "<!ELEMENT ");
	    xmlBufferWriteCHAR(buf, elem->name);
	    xmlBufferWriteChar(buf, " EMPTY>\n");
	    break;
	case XML_ELEMENT_TYPE_ANY:
	    xmlBufferWriteChar(buf, "<!ELEMENT ");
	    xmlBufferWriteCHAR(buf, elem->name);
	    xmlBufferWriteChar(buf, " ANY>\n");
	    break;
	case XML_ELEMENT_TYPE_MIXED:
	    xmlBufferWriteChar(buf, "<!ELEMENT ");
	    xmlBufferWriteCHAR(buf, elem->name);
	    xmlBufferWriteChar(buf, " ");
	    xmlDumpElementContent(buf, elem->content, 1);
	    xmlBufferWriteChar(buf, ">\n");
	    break;
	case XML_ELEMENT_TYPE_ELEMENT:
	    xmlBufferWriteChar(buf, "<!ELEMENT ");
	    xmlBufferWriteCHAR(buf, elem->name);
	    xmlBufferWriteChar(buf, " ");
	    xmlDumpElementContent(buf, elem->content, 1);
	    xmlBufferWriteChar(buf, ">\n");
	    break;
	default:
	    xmlGenericError(xmlGenericErrorContext,
		"xmlDumpElementDecl: internal: unknown type %d\n",
		    elem->etype);
    }
}

/**
 * xmlDumpElementTable:
 * @buf:  the XML buffer output
 * @table:  An element table
 *
 * This will dump the content of the element table as an XML DTD definition
 */
void
xmlDumpElementTable(xmlBufferPtr buf, xmlElementTablePtr table) {
    xmlHashScan(table, (xmlHashScanner) xmlDumpElementDecl, buf);
}

/**
 * xmlCreateEnumeration:
 * @name:  the enumeration name or NULL
 *
 * create and initialize an enumeration attribute node.
 *
 * Returns the xmlEnumerationPtr just created or NULL in case
 *                of error.
 */
xmlEnumerationPtr
xmlCreateEnumeration(xmlChar *name) {
    xmlEnumerationPtr ret;

    ret = (xmlEnumerationPtr) xmlMalloc(sizeof(xmlEnumeration));
    if (ret == NULL) {
        xmlGenericError(xmlGenericErrorContext,
		"xmlCreateEnumeration : xmlMalloc(%ld) failed\n",
	        (long)sizeof(xmlEnumeration));
        return(NULL);
    }
    memset(ret, 0, sizeof(xmlEnumeration));

    if (name != NULL)
        ret->name = xmlStrdup(name);
    return(ret);
}

/**
 * xmlFreeEnumeration:
 * @cur:  the tree to free.
 *
 * free an enumeration attribute node (recursive).
 */
void
xmlFreeEnumeration(xmlEnumerationPtr cur) {
    if (cur == NULL) return;

    if (cur->next != NULL) xmlFreeEnumeration(cur->next);

    if (cur->name != NULL) xmlFree((xmlChar *) cur->name);
    memset(cur, -1, sizeof(xmlEnumeration));
    xmlFree(cur);
}

/**
 * xmlCopyEnumeration:
 * @cur:  the tree to copy.
 *
 * Copy an enumeration attribute node (recursive).
 *
 * Returns the xmlEnumerationPtr just created or NULL in case
 *                of error.
 */
xmlEnumerationPtr
xmlCopyEnumeration(xmlEnumerationPtr cur) {
    xmlEnumerationPtr ret;

    if (cur == NULL) return(NULL);
    ret = xmlCreateEnumeration((xmlChar *) cur->name);

    if (cur->next != NULL) ret->next = xmlCopyEnumeration(cur->next);
    else ret->next = NULL;

    return(ret);
}

/**
 * xmlDumpEnumeration:
 * @buf:  the XML buffer output
 * @enum:  An enumeration
 *
 * This will dump the content of the enumeration
 */
void
xmlDumpEnumeration(xmlBufferPtr buf, xmlEnumerationPtr cur) {
    if (cur == NULL)  return;
    
    xmlBufferWriteCHAR(buf, cur->name);
    if (cur->next == NULL)
	xmlBufferWriteChar(buf, ")");
    else {
	xmlBufferWriteChar(buf, " | ");
	xmlDumpEnumeration(buf, cur->next);
    }
}

/**
 * xmlCreateAttributeTable:
 *
 * create and initialize an empty attribute hash table.
 *
 * Returns the xmlAttributeTablePtr just created or NULL in case
 *                of error.
 */
xmlAttributeTablePtr
xmlCreateAttributeTable(void) {
    return(xmlHashCreate(0));
}

/**
 * xmlScanAttributeDeclCallback:
 * @attr:  the attribute decl
 * @list:  the list to update
 *
 * Callback called by xmlScanAttributeDecl when a new attribute
 * has to be entered in the list.
 */
void
xmlScanAttributeDeclCallback(xmlAttributePtr attr, xmlAttributePtr *list,
	                     const xmlChar* name) {
    attr->nexth = *list;
    *list = attr;
}

/**
 * xmlScanAttributeDecl:
 * @dtd:  pointer to the DTD
 * @elem:  the element name
 *
 * When inserting a new element scan the DtD for existing attributes
 * for taht element and initialize the Attribute chain
 *
 * Returns the pointer to the first attribute decl in the chain,
 *         possibly NULL.
 */
xmlAttributePtr
xmlScanAttributeDecl(xmlDtdPtr dtd, const xmlChar *elem) {
    xmlAttributePtr ret = NULL;
    xmlAttributeTablePtr table;

    if (dtd == NULL) {
        xmlGenericError(xmlGenericErrorContext,
		"xmlScanAttributeDecl: dtd == NULL\n");
	return(NULL);
    }
    if (elem == NULL) {
        xmlGenericError(xmlGenericErrorContext,
		"xmlScanAttributeDecl: elem == NULL\n");
	return(NULL);
    }
    table = (xmlAttributeTablePtr) dtd->attributes;
    if (table == NULL) 
        return(NULL);

    /* WRONG !!! */
    xmlHashScan3(table, NULL, NULL, elem,
	        (xmlHashScanner) xmlScanAttributeDeclCallback, &ret);
    return(ret);
}

/**
 * xmlScanIDAttributeDecl:
 * @ctxt:  the validation context
 * @elem:  the element name
 *
 * Verify that the element don't have too many ID attributes
 * declared.
 *
 * Returns the number of ID attributes found.
 */
int
xmlScanIDAttributeDecl(xmlValidCtxtPtr ctxt, xmlElementPtr elem) {
    xmlAttributePtr cur;
    int ret = 0;

    if (elem == NULL) return(0);
    cur = elem->attributes;
    while (cur != NULL) {
        if (cur->atype == XML_ATTRIBUTE_ID) {
	    ret ++;
	    if (ret > 1)
		VERROR(ctxt->userData, 
	       "Element %s has too may ID attributes defined : %s\n",
		       elem->name, cur->name);
	}
	cur = cur->nexth;
    }
    return(ret);
}

/**
 * xmlFreeAttribute:
 * @elem:  An attribute
 *
 * Deallocate the memory used by an attribute definition
 */
void
xmlFreeAttribute(xmlAttributePtr attr) {
    if (attr == NULL) return;
    xmlUnlinkNode((xmlNodePtr) attr);
    if (attr->tree != NULL)
        xmlFreeEnumeration(attr->tree);
    if (attr->elem != NULL)
	xmlFree((xmlChar *) attr->elem);
    if (attr->name != NULL)
	xmlFree((xmlChar *) attr->name);
    if (attr->defaultValue != NULL)
	xmlFree((xmlChar *) attr->defaultValue);
    if (attr->prefix != NULL)
	xmlFree((xmlChar *) attr->prefix);
    memset(attr, -1, sizeof(xmlAttribute));
    xmlFree(attr);
}


/**
 * xmlAddAttributeDecl:
 * @ctxt:  the validation context
 * @dtd:  pointer to the DTD
 * @elem:  the element name
 * @name:  the attribute name
 * @ns:  the attribute namespace prefix
 * @type:  the attribute type
 * @def:  the attribute default type
 * @defaultValue:  the attribute default value
 * @tree:  if it's an enumeration, the associated list
 *
 * Register a new attribute declaration
 * Note that @tree becomes the ownership of the DTD
 *
 * Returns NULL if not new, othervise the attribute decl
 */
xmlAttributePtr
xmlAddAttributeDecl(xmlValidCtxtPtr ctxt, xmlDtdPtr dtd, const xmlChar *elem,
                    const xmlChar *name, const xmlChar *ns,
		    xmlAttributeType type, xmlAttributeDefault def,
		    const xmlChar *defaultValue, xmlEnumerationPtr tree) {
    xmlAttributePtr ret;
    xmlAttributeTablePtr table;
    xmlElementPtr elemDef;

    if (dtd == NULL) {
        xmlGenericError(xmlGenericErrorContext,
		"xmlAddAttributeDecl: dtd == NULL\n");
	xmlFreeEnumeration(tree);
	return(NULL);
    }
    if (name == NULL) {
        xmlGenericError(xmlGenericErrorContext,
		"xmlAddAttributeDecl: name == NULL\n");
	xmlFreeEnumeration(tree);
	return(NULL);
    }
    if (elem == NULL) {
        xmlGenericError(xmlGenericErrorContext,
		"xmlAddAttributeDecl: elem == NULL\n");
	xmlFreeEnumeration(tree);
	return(NULL);
    }
    /*
     * Check the type and possibly the default value.
     */
    switch (type) {
        case XML_ATTRIBUTE_CDATA:
	    break;
        case XML_ATTRIBUTE_ID:
	    break;
        case XML_ATTRIBUTE_IDREF:
	    break;
        case XML_ATTRIBUTE_IDREFS:
	    break;
        case XML_ATTRIBUTE_ENTITY:
	    break;
        case XML_ATTRIBUTE_ENTITIES:
	    break;
        case XML_ATTRIBUTE_NMTOKEN:
	    break;
        case XML_ATTRIBUTE_NMTOKENS:
	    break;
        case XML_ATTRIBUTE_ENUMERATION:
	    break;
        case XML_ATTRIBUTE_NOTATION:
	    break;
	default:
	    xmlGenericError(xmlGenericErrorContext,
		    "xmlAddAttributeDecl: unknown type %d\n", type);
	    xmlFreeEnumeration(tree);
	    return(NULL);
    }
    if ((defaultValue != NULL) && 
        (!xmlValidateAttributeValue(type, defaultValue))) {
	VERROR(ctxt->userData, "Attribute %s on %s: invalid default value\n",
	       elem, name, defaultValue);
	defaultValue = NULL;
    }

    /*
     * Create the Attribute table if needed.
     */
    table = (xmlAttributeTablePtr) dtd->attributes;
    if (table == NULL) {
        table = xmlCreateAttributeTable();
	dtd->attributes = (void *) table;
    }
    if (table == NULL) {
	xmlGenericError(xmlGenericErrorContext,
		"xmlAddAttributeDecl: Table creation failed!\n");
        return(NULL);
    }


    ret = (xmlAttributePtr) xmlMalloc(sizeof(xmlAttribute));
    if (ret == NULL) {
	xmlGenericError(xmlGenericErrorContext,
		"xmlAddAttributeDecl: out of memory\n");
	return(NULL);
    }
    memset(ret, 0, sizeof(xmlAttribute));
    ret->type = XML_ATTRIBUTE_DECL;

    /*
     * fill the structure.
     */
    ret->atype = type;
    ret->name = xmlStrdup(name);
    ret->prefix = xmlStrdup(ns);
    ret->elem = xmlStrdup(elem);
    ret->def = def;
    ret->tree = tree;
    if (defaultValue != NULL)
	ret->defaultValue = xmlStrdup(defaultValue);

    /*
     * Validity Check:
     * Search the DTD for previous declarations of the ATTLIST
     */
    if (xmlHashAddEntry3(table, name, ns, elem, ret) < 0) {
	/*
	 * The attribute is already defined in this Dtd.
	 */
	VWARNING(ctxt->userData,
		 "Attribute %s on %s: already defined\n",
		 name, elem);
	xmlFreeAttribute(ret);
	return(NULL);
    }

    /*
     * Validity Check:
     * Multiple ID per element
     */
    elemDef = xmlGetDtdElementDesc(dtd, elem);
    if (elemDef != NULL) {
        if ((type == XML_ATTRIBUTE_ID) &&
	    (xmlScanIDAttributeDecl(NULL, elemDef) != 0))
	    VERROR(ctxt->userData, 
	   "Element %s has too may ID attributes defined : %s\n",
		   elem, name);
        ret->nexth = elemDef->attributes;
        elemDef->attributes = ret;
    }

    /*
     * Link it to the Dtd
     */
    ret->parent = dtd;
    ret->doc = dtd->doc;
    if (dtd->last == NULL) {
	dtd->children = dtd->last = (xmlNodePtr) ret;
    } else {
        dtd->last->next = (xmlNodePtr) ret;
	ret->prev = dtd->last;
	dtd->last = (xmlNodePtr) ret;
    }
    return(ret);
}

/**
 * xmlFreeAttributeTable:
 * @table:  An attribute table
 *
 * Deallocate the memory used by an entities hash table.
 */
void
xmlFreeAttributeTable(xmlAttributeTablePtr table) {
    xmlHashFree(table, (xmlHashDeallocator) xmlFreeAttribute);
}

/**
 * xmlCopyAttribute:
 * @attr:  An attribute
 *
 * Build a copy of an attribute.
 * 
 * Returns the new xmlAttributePtr or NULL in case of error.
 */
xmlAttributePtr
xmlCopyAttribute(xmlAttributePtr attr) {
    xmlAttributePtr cur;

    cur = (xmlAttributePtr) xmlMalloc(sizeof(xmlAttribute));
    if (cur == NULL) {
	xmlGenericError(xmlGenericErrorContext,
		"xmlCopyAttribute: out of memory !\n");
	return(NULL);
    }
    memset(cur, 0, sizeof(xmlAttribute));
    cur->atype = attr->atype;
    cur->def = attr->def;
    cur->tree = xmlCopyEnumeration(attr->tree);
    if (attr->elem != NULL)
	cur->elem = xmlStrdup(attr->elem);
    if (attr->name != NULL)
	cur->name = xmlStrdup(attr->name);
    if (attr->defaultValue != NULL)
	cur->defaultValue = xmlStrdup(attr->defaultValue);
    return(cur);
}

/**
 * xmlCopyAttributeTable:
 * @table:  An attribute table
 *
 * Build a copy of an attribute table.
 * 
 * Returns the new xmlAttributeTablePtr or NULL in case of error.
 */
xmlAttributeTablePtr
xmlCopyAttributeTable(xmlAttributeTablePtr table) {
    return((xmlAttributeTablePtr) xmlHashCopy(table,
				    (xmlHashCopier) xmlCopyAttribute));
}

/**
 * xmlDumpAttributeDecl:
 * @buf:  the XML buffer output
 * @attr:  An attribute declaration
 *
 * This will dump the content of the attribute declaration as an XML
 * DTD definition
 */
void
xmlDumpAttributeDecl(xmlBufferPtr buf, xmlAttributePtr attr) {
    xmlBufferWriteChar(buf, "<!ATTLIST ");
    xmlBufferWriteCHAR(buf, attr->elem);
    xmlBufferWriteChar(buf, " ");
    if (attr->prefix != NULL) {
	xmlBufferWriteCHAR(buf, attr->prefix);
	xmlBufferWriteChar(buf, ":");
    }
    xmlBufferWriteCHAR(buf, attr->name);
    switch (attr->atype) {
	case XML_ATTRIBUTE_CDATA:
	    xmlBufferWriteChar(buf, " CDATA");
	    break;
	case XML_ATTRIBUTE_ID:
	    xmlBufferWriteChar(buf, " ID");
	    break;
	case XML_ATTRIBUTE_IDREF:
	    xmlBufferWriteChar(buf, " IDREF");
	    break;
	case XML_ATTRIBUTE_IDREFS:
	    xmlBufferWriteChar(buf, " IDREFS");
	    break;
	case XML_ATTRIBUTE_ENTITY:
	    xmlBufferWriteChar(buf, " ENTITY");
	    break;
	case XML_ATTRIBUTE_ENTITIES:
	    xmlBufferWriteChar(buf, " ENTITIES");
	    break;
	case XML_ATTRIBUTE_NMTOKEN:
	    xmlBufferWriteChar(buf, " NMTOKEN");
	    break;
	case XML_ATTRIBUTE_NMTOKENS:
	    xmlBufferWriteChar(buf, " NMTOKENS");
	    break;
	case XML_ATTRIBUTE_ENUMERATION:
	    xmlBufferWriteChar(buf, " (");
	    xmlDumpEnumeration(buf, attr->tree);
	    break;
	case XML_ATTRIBUTE_NOTATION:
	    xmlBufferWriteChar(buf, " NOTATION (");
	    xmlDumpEnumeration(buf, attr->tree);
	    break;
	default:
	    xmlGenericError(xmlGenericErrorContext,
		"xmlDumpAttributeTable: internal: unknown type %d\n",
		    attr->atype);
    }
    switch (attr->def) {
	case XML_ATTRIBUTE_NONE:
	    break;
	case XML_ATTRIBUTE_REQUIRED:
	    xmlBufferWriteChar(buf, " #REQUIRED");
	    break;
	case XML_ATTRIBUTE_IMPLIED:
	    xmlBufferWriteChar(buf, " #IMPLIED");
	    break;
	case XML_ATTRIBUTE_FIXED:
	    xmlBufferWriteChar(buf, " #FIXED");
	    break;
	default:
	    xmlGenericError(xmlGenericErrorContext,
		"xmlDumpAttributeTable: internal: unknown default %d\n",
		    attr->def);
    }
    if (attr->defaultValue != NULL) {
	xmlBufferWriteChar(buf, " ");
	xmlBufferWriteQuotedString(buf, attr->defaultValue);
    }
    xmlBufferWriteChar(buf, ">\n");
}

/**
 * xmlDumpAttributeTable:
 * @buf:  the XML buffer output
 * @table:  An attribute table
 *
 * This will dump the content of the attribute table as an XML DTD definition
 */
void
xmlDumpAttributeTable(xmlBufferPtr buf, xmlAttributeTablePtr table) {
    xmlHashScan(table, (xmlHashScanner) xmlDumpAttributeDecl, buf);
}

/************************************************************************
 *									*
 *				NOTATIONs				*
 *									*
 ************************************************************************/
/**
 * xmlCreateNotationTable:
 *
 * create and initialize an empty notation hash table.
 *
 * Returns the xmlNotationTablePtr just created or NULL in case
 *                of error.
 */
xmlNotationTablePtr
xmlCreateNotationTable(void) {
    return(xmlHashCreate(0));
}

/**
 * xmlFreeNotation:
 * @not:  A notation
 *
 * Deallocate the memory used by an notation definition
 */
void
xmlFreeNotation(xmlNotationPtr nota) {
    if (nota == NULL) return;
    if (nota->name != NULL)
	xmlFree((xmlChar *) nota->name);
    if (nota->PublicID != NULL)
	xmlFree((xmlChar *) nota->PublicID);
    if (nota->SystemID != NULL)
	xmlFree((xmlChar *) nota->SystemID);
    memset(nota, -1, sizeof(xmlNotation));
    xmlFree(nota);
}


/**
 * xmlAddNotationDecl:
 * @dtd:  pointer to the DTD
 * @ctxt:  the validation context
 * @name:  the entity name
 * @PublicID:  the public identifier or NULL
 * @SystemID:  the system identifier or NULL
 *
 * Register a new notation declaration
 *
 * Returns NULL if not, othervise the entity
 */
xmlNotationPtr
xmlAddNotationDecl(xmlValidCtxtPtr ctxt, xmlDtdPtr dtd, const xmlChar *name,
                   const xmlChar *PublicID, const xmlChar *SystemID) {
    xmlNotationPtr ret;
    xmlNotationTablePtr table;

    if (dtd == NULL) {
        xmlGenericError(xmlGenericErrorContext,
		"xmlAddNotationDecl: dtd == NULL\n");
	return(NULL);
    }
    if (name == NULL) {
        xmlGenericError(xmlGenericErrorContext,
		"xmlAddNotationDecl: name == NULL\n");
	return(NULL);
    }
    if ((PublicID == NULL) && (SystemID == NULL)) {
        xmlGenericError(xmlGenericErrorContext,
		"xmlAddNotationDecl: no PUBLIC ID nor SYSTEM ID\n");
    }

    /*
     * Create the Notation table if needed.
     */
    table = (xmlNotationTablePtr) dtd->notations;
    if (table == NULL) 
        dtd->notations = table = xmlCreateNotationTable();
    if (table == NULL) {
	xmlGenericError(xmlGenericErrorContext,
		"xmlAddNotationDecl: Table creation failed!\n");
        return(NULL);
    }

    ret = (xmlNotationPtr) xmlMalloc(sizeof(xmlNotation));
    if (ret == NULL) {
	xmlGenericError(xmlGenericErrorContext,
		"xmlAddNotationDecl: out of memory\n");
	return(NULL);
    }
    memset(ret, 0, sizeof(xmlNotation));

    /*
     * fill the structure.
     */
    ret->name = xmlStrdup(name);
    if (SystemID != NULL)
        ret->SystemID = xmlStrdup(SystemID);
    if (PublicID != NULL)
        ret->PublicID = xmlStrdup(PublicID);

    /*
     * Validity Check:
     * Check the DTD for previous declarations of the ATTLIST
     */
    if (xmlHashAddEntry(table, name, ret)) {
	xmlGenericError(xmlGenericErrorContext,
		"xmlAddNotationDecl: %s already defined\n", name);
	xmlFreeNotation(ret);
	return(NULL);
    }
    return(ret);
}

/**
 * xmlFreeNotationTable:
 * @table:  An notation table
 *
 * Deallocate the memory used by an entities hash table.
 */
void
xmlFreeNotationTable(xmlNotationTablePtr table) {
    xmlHashFree(table, (xmlHashDeallocator) xmlFreeNotation);
}

/**
 * xmlCopyNotation:
 * @nota:  A notation
 *
 * Build a copy of a notation.
 * 
 * Returns the new xmlNotationPtr or NULL in case of error.
 */
xmlNotationPtr
xmlCopyNotation(xmlNotationPtr nota) {
    xmlNotationPtr cur;

    cur = (xmlNotationPtr) xmlMalloc(sizeof(xmlNotation));
    if (cur == NULL) {
	xmlGenericError(xmlGenericErrorContext,
		"xmlCopyNotation: out of memory !\n");
	return(NULL);
    }
    if (nota->name != NULL)
	cur->name = xmlStrdup(nota->name);
    else
	cur->name = NULL;
    if (nota->PublicID != NULL)
	cur->PublicID = xmlStrdup(nota->PublicID);
    else
	cur->PublicID = NULL;
    if (nota->SystemID != NULL)
	cur->SystemID = xmlStrdup(nota->SystemID);
    else
	cur->SystemID = NULL;
    return(cur);
}

/**
 * xmlCopyNotationTable:
 * @table:  A notation table
 *
 * Build a copy of a notation table.
 * 
 * Returns the new xmlNotationTablePtr or NULL in case of error.
 */
xmlNotationTablePtr
xmlCopyNotationTable(xmlNotationTablePtr table) {
    return((xmlNotationTablePtr) xmlHashCopy(table,
				    (xmlHashCopier) xmlCopyNotation));
}

/**
 * xmlDumpNotationDecl:
 * @buf:  the XML buffer output
 * @nota:  A notation declaration
 *
 * This will dump the content the notation declaration as an XML DTD definition
 */
void
xmlDumpNotationDecl(xmlBufferPtr buf, xmlNotationPtr nota) {
    xmlBufferWriteChar(buf, "<!NOTATION ");
    xmlBufferWriteCHAR(buf, nota->name);
    if (nota->PublicID != NULL) {
	xmlBufferWriteChar(buf, " PUBLIC ");
	xmlBufferWriteQuotedString(buf, nota->PublicID);
	if (nota->SystemID != NULL) {
	    xmlBufferWriteChar(buf, " ");
	    xmlBufferWriteCHAR(buf, nota->SystemID);
	}
    } else {
	xmlBufferWriteChar(buf, " SYSTEM ");
	xmlBufferWriteCHAR(buf, nota->SystemID);
    }
    xmlBufferWriteChar(buf, " >\n");
}

/**
 * xmlDumpNotationTable:
 * @buf:  the XML buffer output
 * @table:  A notation table
 *
 * This will dump the content of the notation table as an XML DTD definition
 */
void
xmlDumpNotationTable(xmlBufferPtr buf, xmlNotationTablePtr table) {
    xmlHashScan(table, (xmlHashScanner) xmlDumpNotationDecl, buf);
}

/************************************************************************
 *									*
 *				IDs					*
 *									*
 ************************************************************************/
/**
 * xmlCreateIDTable:
 *
 * create and initialize an empty id hash table.
 *
 * Returns the xmlIDTablePtr just created or NULL in case
 *                of error.
 */
xmlIDTablePtr
xmlCreateIDTable(void) {
    return(xmlHashCreate(0));
}

/**
 * xmlFreeID:
 * @not:  A id
 *
 * Deallocate the memory used by an id definition
 */
void
xmlFreeID(xmlIDPtr id) {
    if (id == NULL) return;
    if (id->value != NULL)
	xmlFree((xmlChar *) id->value);
    memset(id, -1, sizeof(xmlID));
    xmlFree(id);
}

/**
 * xmlAddID:
 * @ctxt:  the validation context
 * @doc:  pointer to the document
 * @value:  the value name
 * @attr:  the attribute holding the ID
 *
 * Register a new id declaration
 *
 * Returns NULL if not, othervise the new xmlIDPtr
 */
xmlIDPtr 
xmlAddID(xmlValidCtxtPtr ctxt, xmlDocPtr doc, const xmlChar *value,
         xmlAttrPtr attr) {
    xmlIDPtr ret;
    xmlIDTablePtr table;

    if (doc == NULL) {
        xmlGenericError(xmlGenericErrorContext,
		"xmlAddIDDecl: doc == NULL\n");
	return(NULL);
    }
    if (value == NULL) {
        xmlGenericError(xmlGenericErrorContext,
		"xmlAddIDDecl: value == NULL\n");
	return(NULL);
    }
    if (attr == NULL) {
        xmlGenericError(xmlGenericErrorContext,
		"xmlAddIDDecl: attr == NULL\n");
	return(NULL);
    }

    /*
     * Create the ID table if needed.
     */
    table = (xmlIDTablePtr) doc->ids;
    if (table == NULL) 
        doc->ids = table = xmlCreateIDTable();
    if (table == NULL) {
	xmlGenericError(xmlGenericErrorContext,
		"xmlAddID: Table creation failed!\n");
        return(NULL);
    }

    ret = (xmlIDPtr) xmlMalloc(sizeof(xmlID));
    if (ret == NULL) {
	xmlGenericError(xmlGenericErrorContext,
		"xmlAddID: out of memory\n");
	return(NULL);
    }

    /*
     * fill the structure.
     */
    ret->value = xmlStrdup(value);
    ret->attr = attr;

    if (xmlHashAddEntry(table, value, ret) < 0) {
	/*
	 * The id is already defined in this Dtd.
	 */
	VERROR(ctxt->userData, "ID %s already defined\n", value);
	xmlFreeID(ret);
	return(NULL);
    }
    return(ret);
}

/**
 * xmlFreeIDTable:
 * @table:  An id table
 *
 * Deallocate the memory used by an ID hash table.
 */
void
xmlFreeIDTable(xmlIDTablePtr table) {
    xmlHashFree(table, (xmlHashDeallocator) xmlFreeID);
}

/**
 * xmlIsID:
 * @doc:  the document
 * @elem:  the element carrying the attribute
 * @attr:  the attribute
 *
 * Determine whether an attribute is of type ID. In case we have Dtd(s)
 * then this is simple, otherwise we use an heuristic: name ID (upper
 * or lowercase).
 *
 * Returns 0 or 1 depending on the lookup result
 */
int
xmlIsID(xmlDocPtr doc, xmlNodePtr elem, xmlAttrPtr attr) {
    if (doc == NULL) return(0);
    if (attr == NULL) return(0);
    if ((doc->intSubset == NULL) && (doc->extSubset == NULL)) {
	return(0);
    } else if (doc->type == XML_HTML_DOCUMENT_NODE) {
        if ((xmlStrEqual(BAD_CAST "id", attr->name)) ||
	    (xmlStrEqual(BAD_CAST "name", attr->name)))
	    return(1);
	return(0);    
    } else {
	xmlAttributePtr attrDecl;

	if (elem == NULL) return(0);
	attrDecl = xmlGetDtdAttrDesc(doc->intSubset, elem->name, attr->name);
	if ((attrDecl == NULL) && (doc->extSubset != NULL))
	    attrDecl = xmlGetDtdAttrDesc(doc->extSubset, elem->name,
	                                 attr->name);

        if ((attrDecl != NULL) && (attrDecl->atype == XML_ATTRIBUTE_ID))
	    return(1);
    }
    return(0);
}

/**
 * xmlRemoveID
 * @doc:  the document
 * @attr:  the attribute
 *
 * Remove the given attribute from the ID table maintained internally.
 *
 * Returns -1 if the lookup failed and 0 otherwise
 */
int
xmlRemoveID(xmlDocPtr doc, xmlAttrPtr attr) {
    xmlAttrPtr cur;
    xmlIDTablePtr table;
    xmlChar *ID;

    if (doc == NULL) return(-1);
    if (attr == NULL) return(-1);
    table = (xmlIDTablePtr) doc->ids;
    if (table == NULL) 
        return(-1);

    if (attr == NULL)
	return(-1);
    ID = xmlNodeListGetString(doc, attr->children, 1);
    if (ID == NULL)
	return(-1);
    cur = xmlHashLookup(table, ID);
    if (cur != attr) {
	xmlFree(ID);
	return(-1);
    }
    xmlHashUpdateEntry(table, ID, NULL, (xmlHashDeallocator) xmlFreeID);
    xmlFree(ID);
    return(0);
}

/**
 * xmlGetID:
 * @doc:  pointer to the document
 * @ID:  the ID value
 *
 * Search the attribute declaring the given ID
 *
 * Returns NULL if not found, otherwise the xmlAttrPtr defining the ID
 */
xmlAttrPtr 
xmlGetID(xmlDocPtr doc, const xmlChar *ID) {
    xmlIDTablePtr table;
    xmlIDPtr id;

    if (doc == NULL) {
        xmlGenericError(xmlGenericErrorContext, "xmlGetID: doc == NULL\n");
	return(NULL);
    }

    if (ID == NULL) {
        xmlGenericError(xmlGenericErrorContext, "xmlGetID: ID == NULL\n");
	return(NULL);
    }

    table = (xmlIDTablePtr) doc->ids;
    if (table == NULL) 
        return(NULL);

    id = xmlHashLookup(table, ID);
    if (id == NULL)
	return(NULL);
    return(id->attr);
}

/************************************************************************
 *									*
 *				Refs					*
 *									*
 ************************************************************************/
/**
 * xmlCreateRefTable:
 *
 * create and initialize an empty ref hash table.
 *
 * Returns the xmlRefTablePtr just created or NULL in case
 *                of error.
 */
xmlRefTablePtr
xmlCreateRefTable(void) {
    return(xmlHashCreate(0));
}

/**
 * xmlFreeRef:
 * @ref:  A ref
 *
 * Deallocate the memory used by an ref definition
 */
void
xmlFreeRef(xmlRefPtr ref) {
    if (ref == NULL) return;
    if (ref->value != NULL)
	xmlFree((xmlChar *) ref->value);
    memset(ref, -1, sizeof(xmlRef));
    xmlFree(ref);
}

/**
 * xmlAddRef:
 * @ctxt:  the validation context
 * @doc:  pointer to the document
 * @value:  the value name
 * @attr:  the attribute holding the Ref
 *
 * Register a new ref declaration
 *
 * Returns NULL if not, othervise the new xmlRefPtr
 */
xmlRefPtr 
xmlAddRef(xmlValidCtxtPtr ctxt, xmlDocPtr doc, const xmlChar *value,
         xmlAttrPtr attr) {
    xmlRefPtr ret;
    xmlRefTablePtr table;

    if (doc == NULL) {
        xmlGenericError(xmlGenericErrorContext,
		"xmlAddRefDecl: doc == NULL\n");
	return(NULL);
    }
    if (value == NULL) {
        xmlGenericError(xmlGenericErrorContext,
		"xmlAddRefDecl: value == NULL\n");
	return(NULL);
    }
    if (attr == NULL) {
        xmlGenericError(xmlGenericErrorContext,
		"xmlAddRefDecl: attr == NULL\n");
	return(NULL);
    }

    /*
     * Create the Ref table if needed.
     */
    table = (xmlRefTablePtr) doc->refs;
    if (table == NULL) 
        doc->refs = table = xmlCreateRefTable();
    if (table == NULL) {
	xmlGenericError(xmlGenericErrorContext,
		"xmlAddRef: Table creation failed!\n");
        return(NULL);
    }

    ret = (xmlRefPtr) xmlMalloc(sizeof(xmlRef));
    if (ret == NULL) {
	xmlGenericError(xmlGenericErrorContext,
		"xmlAddRef: out of memory\n");
	return(NULL);
    }

    /*
     * fill the structure.
     */
    ret->value = xmlStrdup(value);
    ret->attr = attr;

    /*
     * !!! Should we keep track of all refs ? and use xmlHashAddEntry2 ?
     */
    if (xmlHashAddEntry(table, value, ret) < 0) {
	/*
	 * Since there is no discrimination on error returns
	 * from xmlHashAddEntry, I'm presuming <0 means the
	 * key already exists.
	 */
	xmlHashUpdateEntry(table, value, ret, (xmlHashDeallocator) xmlFreeRef);
    }
    return(ret);
}

/**
 * xmlFreeRefTable:
 * @table:  An ref table
 *
 * Deallocate the memory used by an Ref hash table.
 */
void
xmlFreeRefTable(xmlRefTablePtr table) {
    xmlHashFree(table, (xmlHashDeallocator) xmlFreeRef);
}

/**
 * xmlIsRef:
 * @doc:  the document
 * @elem:  the element carrying the attribute
 * @attr:  the attribute
 *
 * Determine whether an attribute is of type Ref. In case we have Dtd(s)
 * then this is simple, otherwise we use an heuristic: name Ref (upper
 * or lowercase).
 *
 * Returns 0 or 1 depending on the lookup result
 */
int
xmlIsRef(xmlDocPtr doc, xmlNodePtr elem, xmlAttrPtr attr) {
    if ((doc->intSubset == NULL) && (doc->extSubset == NULL)) {
        return(0);
    } else if (doc->type == XML_HTML_DOCUMENT_NODE) {
	/* TODO @@@ */
	return(0);    
    } else {
	xmlAttributePtr attrDecl;

	attrDecl = xmlGetDtdAttrDesc(doc->intSubset, elem->name, attr->name);
	if ((attrDecl == NULL) && (doc->extSubset != NULL))
	    attrDecl = xmlGetDtdAttrDesc(doc->extSubset, elem->name,
	                                 attr->name);

        if ((attrDecl != NULL) && (attrDecl->atype == XML_ATTRIBUTE_IDREF))
	    return(1);
    }
    return(0);
}

/**
 * xmlRemoveRef
 * @doc:  the document
 * @attr:  the attribute
 *
 * Remove the given attribute from the Ref table maintained internally.
 *
 * Returns -1 if the lookup failed and 0 otherwise
 */
int
xmlRemoveRef(xmlDocPtr doc, xmlAttrPtr attr) {
    xmlAttrPtr cur;
    xmlRefTablePtr table;
    xmlChar *ID;

    if (doc == NULL) return(-1);
    if (attr == NULL) return(-1);
    table = (xmlRefTablePtr) doc->refs;
    if (table == NULL) 
        return(-1);

    if (attr == NULL)
	return(-1);
    ID = xmlNodeListGetString(doc, attr->children, 1);
    if (ID == NULL)
	return(-1);
    cur = xmlHashLookup(table, ID);
    if (cur != attr) {
	xmlFree(ID);
	return(-1);
    }
    xmlHashUpdateEntry(table, ID, NULL, (xmlHashDeallocator) xmlFreeRef);
    xmlFree(ID);
    return(0);
}

/**
 * xmlGetRef:
 * @doc:  pointer to the document
 * @Ref:  the Ref value
 *
 * Search the next attribute declaring the given Ref
 *
 * Returns NULL if not found, otherwise the xmlAttrPtr defining the Ref
 */
xmlAttrPtr 
xmlGetRef(xmlDocPtr doc, const xmlChar *Ref) {
    xmlRefTablePtr table;

    if (doc == NULL) {
        xmlGenericError(xmlGenericErrorContext, "xmlGetRef: doc == NULL\n");
	return(NULL);
    }

    if (Ref == NULL) {
        xmlGenericError(xmlGenericErrorContext, "xmlGetRef: Ref == NULL\n");
	return(NULL);
    }

    table = (xmlRefTablePtr) doc->refs;
    if (table == NULL) 
        return(NULL);

    return(xmlHashLookup(table, Ref));
}

/************************************************************************
 *									*
 *		Routines for validity checking				*
 *									*
 ************************************************************************/

/**
 * xmlGetDtdElementDesc:
 * @dtd:  a pointer to the DtD to search
 * @name:  the element name
 *
 * Search the Dtd for the description of this element
 *
 * returns the xmlElementPtr if found or NULL
 */

xmlElementPtr
xmlGetDtdElementDesc(xmlDtdPtr dtd, const xmlChar *name) {
    xmlElementTablePtr table;
    xmlElementPtr cur;
    xmlChar *uqname = NULL, *prefix = NULL;

    if (dtd == NULL) return(NULL);
    if (dtd->elements == NULL) return(NULL);
    table = (xmlElementTablePtr) dtd->elements;

    uqname = xmlSplitQName2(name, &prefix);
    if (uqname != NULL) {
	cur = xmlHashLookup2(table, uqname, prefix);
	if (prefix != NULL) xmlFree(prefix);
	if (uqname != NULL) xmlFree(uqname);
    } else
	cur = xmlHashLookup2(table, name, NULL);
    return(cur);
}

/**
 * xmlGetDtdQElementDesc:
 * @dtd:  a pointer to the DtD to search
 * @name:  the element name
 * @prefix:  the element namespace prefix
 *
 * Search the Dtd for the description of this element
 *
 * returns the xmlElementPtr if found or NULL
 */

xmlElementPtr
xmlGetDtdQElementDesc(xmlDtdPtr dtd, const xmlChar *name,
	              const xmlChar *prefix) {
    xmlElementTablePtr table;

    if (dtd == NULL) return(NULL);
    if (dtd->elements == NULL) return(NULL);
    table = (xmlElementTablePtr) dtd->elements;

    return(xmlHashLookup2(table, name, prefix));
}

/**
 * xmlGetDtdAttrDesc:
 * @dtd:  a pointer to the DtD to search
 * @elem:  the element name
 * @name:  the attribute name
 *
 * Search the Dtd for the description of this attribute on
 * this element.
 *
 * returns the xmlAttributePtr if found or NULL
 */

xmlAttributePtr
xmlGetDtdAttrDesc(xmlDtdPtr dtd, const xmlChar *elem, const xmlChar *name) {
    xmlAttributeTablePtr table;
    xmlAttributePtr cur;
    xmlChar *uqname = NULL, *prefix = NULL;

    if (dtd == NULL) return(NULL);
    if (dtd->attributes == NULL) return(NULL);

    table = (xmlAttributeTablePtr) dtd->attributes;
    if (table == NULL)
	return(NULL);

    uqname = xmlSplitQName2(name, &prefix);

    if (uqname != NULL) {
	cur = xmlHashLookup3(table, uqname, prefix, elem);
	if (prefix != NULL) xmlFree(prefix);
	if (uqname != NULL) xmlFree(uqname);
    } else
	cur = xmlHashLookup3(table, name, NULL, elem);
    return(cur);
}

/**
 * xmlGetDtdQAttrDesc:
 * @dtd:  a pointer to the DtD to search
 * @elem:  the element name
 * @name:  the attribute name
 * @prefix:  the attribute namespace prefix
 *
 * Search the Dtd for the description of this qualified attribute on
 * this element.
 *
 * returns the xmlAttributePtr if found or NULL
 */

xmlAttributePtr
xmlGetDtdQAttrDesc(xmlDtdPtr dtd, const xmlChar *elem, const xmlChar *name,
	          const xmlChar *prefix) {
    xmlAttributeTablePtr table;

    if (dtd == NULL) return(NULL);
    if (dtd->attributes == NULL) return(NULL);
    table = (xmlAttributeTablePtr) dtd->attributes;

    return(xmlHashLookup3(table, name, prefix, elem));
}

/**
 * xmlGetDtdNotationDesc:
 * @dtd:  a pointer to the DtD to search
 * @name:  the notation name
 *
 * Search the Dtd for the description of this notation
 *
 * returns the xmlNotationPtr if found or NULL
 */

xmlNotationPtr
xmlGetDtdNotationDesc(xmlDtdPtr dtd, const xmlChar *name) {
    xmlNotationTablePtr table;

    if (dtd == NULL) return(NULL);
    if (dtd->notations == NULL) return(NULL);
    table = (xmlNotationTablePtr) dtd->notations;

    return(xmlHashLookup(table, name));
}

/**
 * xmlValidateNotationUse:
 * @ctxt:  the validation context
 * @doc:  the document
 * @notationName:  the notation name to check
 *
 * Validate that the given mame match a notation declaration.
 * - [ VC: Notation Declared ]
 *
 * returns 1 if valid or 0 otherwise
 */

int
xmlValidateNotationUse(xmlValidCtxtPtr ctxt, xmlDocPtr doc,
                       const xmlChar *notationName) {
    xmlNotationPtr notaDecl;
    if ((doc == NULL) || (doc->intSubset == NULL)) return(-1);

    notaDecl = xmlGetDtdNotationDesc(doc->intSubset, notationName);
    if ((notaDecl == NULL) && (doc->extSubset != NULL))
	notaDecl = xmlGetDtdNotationDesc(doc->extSubset, notationName);

    if (notaDecl == NULL) {
	VERROR(ctxt->userData, "NOTATION %s is not declared\n",
	       notationName);
	return(0);
    }
    return(1);
}

/**
 * xmlIsMixedElement
 * @doc:  the document
 * @name:  the element name
 *
 * Search in the DtDs whether an element accept Mixed content (or ANY)
 * basically if it is supposed to accept text childs
 *
 * returns 0 if no, 1 if yes, and -1 if no element description is available
 */

int
xmlIsMixedElement(xmlDocPtr doc, const xmlChar *name) {
    xmlElementPtr elemDecl;

    if ((doc == NULL) || (doc->intSubset == NULL)) return(-1);

    elemDecl = xmlGetDtdElementDesc(doc->intSubset, name);
    if ((elemDecl == NULL) && (doc->extSubset != NULL))
	elemDecl = xmlGetDtdElementDesc(doc->extSubset, name);
    if (elemDecl == NULL) return(-1);
    switch (elemDecl->etype) {
	case XML_ELEMENT_TYPE_ELEMENT:
	    return(0);
        case XML_ELEMENT_TYPE_EMPTY:
	    /*
	     * return 1 for EMPTY since we want VC error to pop up
	     * on <empty>     </empty> for example
	     */
	case XML_ELEMENT_TYPE_ANY:
	case XML_ELEMENT_TYPE_MIXED:
	    return(1);
    }
    return(1);
}

/**
 * xmlValidateNameValue:
 * @value:  an Name value
 *
 * Validate that the given value match Name production
 *
 * returns 1 if valid or 0 otherwise
 */

int
xmlValidateNameValue(const xmlChar *value) {
    const xmlChar *cur;

    if (value == NULL) return(0);
    cur = value;
    
    if (!IS_LETTER(*cur) && (*cur != '_') &&
        (*cur != ':')) {
	return(0);
    }

    while ((IS_LETTER(*cur)) || (IS_DIGIT(*cur)) ||
           (*cur == '.') || (*cur == '-') ||
	   (*cur == '_') || (*cur == ':') || 
	   (IS_COMBINING(*cur)) ||
	   (IS_EXTENDER(*cur)))
	   cur++;

    if (*cur != 0) return(0);

    return(1);
}

/**
 * xmlValidateNamesValue:
 * @value:  an Names value
 *
 * Validate that the given value match Names production
 *
 * returns 1 if valid or 0 otherwise
 */

int
xmlValidateNamesValue(const xmlChar *value) {
    const xmlChar *cur;

    if (value == NULL) return(0);
    cur = value;
    
    if (!IS_LETTER(*cur) && (*cur != '_') &&
        (*cur != ':')) {
	return(0);
    }

    while ((IS_LETTER(*cur)) || (IS_DIGIT(*cur)) ||
           (*cur == '.') || (*cur == '-') ||
	   (*cur == '_') || (*cur == ':') || 
	   (IS_COMBINING(*cur)) ||
	   (IS_EXTENDER(*cur)))
	   cur++;

    while (IS_BLANK(*cur)) {
	while (IS_BLANK(*cur)) cur++;

	if (!IS_LETTER(*cur) && (*cur != '_') &&
	    (*cur != ':')) {
	    return(0);
	}

	while ((IS_LETTER(*cur)) || (IS_DIGIT(*cur)) ||
	       (*cur == '.') || (*cur == '-') ||
	       (*cur == '_') || (*cur == ':') || 
	       (IS_COMBINING(*cur)) ||
	       (IS_EXTENDER(*cur)))
	       cur++;
    }

    if (*cur != 0) return(0);

    return(1);
}

/**
 * xmlValidateNmtokenValue:
 * @value:  an Mntoken value
 *
 * Validate that the given value match Nmtoken production
 *
 * [ VC: Name Token ]
 * 
 * returns 1 if valid or 0 otherwise
 */

int
xmlValidateNmtokenValue(const xmlChar *value) {
    const xmlChar *cur;

    if (value == NULL) return(0);
    cur = value;
    
    if (!IS_LETTER(*cur) && !IS_DIGIT(*cur) &&
        (*cur != '.') && (*cur != '-') &&
        (*cur != '_') && (*cur != ':') && 
        (!IS_COMBINING(*cur)) &&
        (!IS_EXTENDER(*cur)))
	return(0);

    while ((IS_LETTER(*cur)) || (IS_DIGIT(*cur)) ||
           (*cur == '.') || (*cur == '-') ||
	   (*cur == '_') || (*cur == ':') || 
	   (IS_COMBINING(*cur)) ||
	   (IS_EXTENDER(*cur)))
	   cur++;

    if (*cur != 0) return(0);

    return(1);
}

/**
 * xmlValidateNmtokensValue:
 * @value:  an Mntokens value
 *
 * Validate that the given value match Nmtokens production
 *
 * [ VC: Name Token ]
 * 
 * returns 1 if valid or 0 otherwise
 */

int
xmlValidateNmtokensValue(const xmlChar *value) {
    const xmlChar *cur;

    if (value == NULL) return(0);
    cur = value;
    
    while (IS_BLANK(*cur)) cur++;
    if (!IS_LETTER(*cur) && !IS_DIGIT(*cur) &&
        (*cur != '.') && (*cur != '-') &&
        (*cur != '_') && (*cur != ':') && 
        (!IS_COMBINING(*cur)) &&
        (!IS_EXTENDER(*cur)))
	return(0);

    while ((IS_LETTER(*cur)) || (IS_DIGIT(*cur)) ||
           (*cur == '.') || (*cur == '-') ||
	   (*cur == '_') || (*cur == ':') || 
	   (IS_COMBINING(*cur)) ||
	   (IS_EXTENDER(*cur)))
	   cur++;

    while (IS_BLANK(*cur)) {
	while (IS_BLANK(*cur)) cur++;
	if (*cur == 0) return(1);

	if (!IS_LETTER(*cur) && !IS_DIGIT(*cur) &&
	    (*cur != '.') && (*cur != '-') &&
	    (*cur != '_') && (*cur != ':') && 
	    (!IS_COMBINING(*cur)) &&
	    (!IS_EXTENDER(*cur)))
	    return(0);

	while ((IS_LETTER(*cur)) || (IS_DIGIT(*cur)) ||
	       (*cur == '.') || (*cur == '-') ||
	       (*cur == '_') || (*cur == ':') || 
	       (IS_COMBINING(*cur)) ||
	       (IS_EXTENDER(*cur)))
	       cur++;
    }

    if (*cur != 0) return(0);

    return(1);
}

/**
 * xmlValidateNotationDecl:
 * @ctxt:  the validation context
 * @doc:  a document instance
 * @nota:  a notation definition
 *
 * Try to validate a single notation definition
 * basically it does the following checks as described by the
 * XML-1.0 recommendation:
 *  - it seems that no validity constraing exist on notation declarations
 * But this function get called anyway ...
 *
 * returns 1 if valid or 0 otherwise
 */

int
xmlValidateNotationDecl(xmlValidCtxtPtr ctxt, xmlDocPtr doc,
                         xmlNotationPtr nota) {
    int ret = 1;

    return(ret);
}

/**
 * xmlValidateAttributeValue:
 * @type:  an attribute type
 * @value:  an attribute value
 *
 * Validate that the given attribute value match  the proper production
 *
 * [ VC: ID ]
 * Values of type ID must match the Name production....
 *
 * [ VC: IDREF ]
 * Values of type IDREF must match the Name production, and values
 * of type IDREFS must match Names ...
 *
 * [ VC: Entity Name ]
 * Values of type ENTITY must match the Name production, values
 * of type ENTITIES must match Names ...
 *
 * [ VC: Name Token ]
 * Values of type NMTOKEN must match the Nmtoken production; values
 * of type NMTOKENS must match Nmtokens. 
 *
 * returns 1 if valid or 0 otherwise
 */

int
xmlValidateAttributeValue(xmlAttributeType type, const xmlChar *value) {
    switch (type) {
	case XML_ATTRIBUTE_ENTITIES:
	case XML_ATTRIBUTE_IDREFS:
	    return(xmlValidateNamesValue(value));
	case XML_ATTRIBUTE_ENTITY:
	case XML_ATTRIBUTE_IDREF:
	case XML_ATTRIBUTE_ID:
	case XML_ATTRIBUTE_NOTATION:
	    return(xmlValidateNameValue(value));
	case XML_ATTRIBUTE_NMTOKENS:
	case XML_ATTRIBUTE_ENUMERATION:
	    return(xmlValidateNmtokensValue(value));
	case XML_ATTRIBUTE_NMTOKEN:
	    return(xmlValidateNmtokenValue(value));
        case XML_ATTRIBUTE_CDATA:
	    break;
    }
    return(1);
}

/**
 * xmlValidateAttributeValue2:
 * @ctxt:  the validation context
 * @doc:  the document
 * @name:  the attribute name (used for error reporting only)
 * @type:  the attribute type
 * @value:  the attribute value
 *
 * Validate that the given attribute value match a given type.
 * This typically cannot be done before having finished parsing
 * the subsets.
 *
 * [ VC: IDREF ]
 * Values of type IDREF must match one of the declared IDs
 * Values of type IDREFS must match a sequence of the declared IDs
 * each Name must match the value of an ID attribute on some element
 * in the XML document; i.e. IDREF values must match the value of
 * some ID attribute
 *
 * [ VC: Entity Name ]
 * Values of type ENTITY must match one declared entity
 * Values of type ENTITIES must match a sequence of declared entities
 *
 * [ VC: Notation Attributes ]
 * all notation names in the declaration must be declared.
 *
 * returns 1 if valid or 0 otherwise
 */

int
xmlValidateAttributeValue2(xmlValidCtxtPtr ctxt, xmlDocPtr doc,
      const xmlChar *name, xmlAttributeType type, const xmlChar *value) {
    int ret = 1;
    switch (type) {
	case XML_ATTRIBUTE_IDREFS:
	case XML_ATTRIBUTE_IDREF:
	case XML_ATTRIBUTE_ID:
	case XML_ATTRIBUTE_NMTOKENS:
	case XML_ATTRIBUTE_ENUMERATION:
	case XML_ATTRIBUTE_NMTOKEN:
        case XML_ATTRIBUTE_CDATA:
	    break;
	case XML_ATTRIBUTE_ENTITY: {
	    xmlEntityPtr ent;

	    ent = xmlGetDocEntity(doc, value);
	    if (ent == NULL) {
		VERROR(ctxt->userData, 
   "ENTITY attribute %s reference an unknown entity \"%s\"\n",
		       name, value);
		ret = 0;
	    } else if (ent->etype != XML_EXTERNAL_GENERAL_UNPARSED_ENTITY) {
		VERROR(ctxt->userData, 
   "ENTITY attribute %s reference an entity \"%s\" of wrong type\n",
		       name, value);
		ret = 0;
	    }
	    break;
        }
	case XML_ATTRIBUTE_ENTITIES: {
	    xmlChar *dup, *nam = NULL, *cur, save;
	    xmlEntityPtr ent;

	    dup = xmlStrdup(value);
	    if (dup == NULL)
		return(0);
	    cur = dup;
	    while (*cur != 0) {
		nam = cur;
		while ((*cur != 0) && (!IS_BLANK(*cur))) cur++;
		save = *cur;
		*cur = 0;
		ent = xmlGetDocEntity(doc, nam);
		if (ent == NULL) {
		    VERROR(ctxt->userData, 
       "ENTITIES attribute %s reference an unknown entity \"%s\"\n",
			   name, nam);
		    ret = 0;
		} else if (ent->etype != XML_EXTERNAL_GENERAL_UNPARSED_ENTITY) {
		    VERROR(ctxt->userData, 
       "ENTITIES attribute %s reference an entity \"%s\" of wrong type\n",
			   name, nam);
		    ret = 0;
		}
		if (save == 0)
		    break;
		*cur = save;
		while (IS_BLANK(*cur)) cur++;
	    }
	    xmlFree(dup);
	    break;
	}
	case XML_ATTRIBUTE_NOTATION: {
	    xmlNotationPtr nota;

	    nota = xmlGetDtdNotationDesc(doc->intSubset, value);
	    if ((nota == NULL) && (doc->extSubset != NULL))
		nota = xmlGetDtdNotationDesc(doc->extSubset, value);

	    if (nota == NULL) {
		VERROR(ctxt->userData, 
       "NOTATION attribute %s reference an unknown notation \"%s\"\n",
		       name, value);
		ret = 0;
	    }
	    break;
        }
    }
    return(ret);
}

/**
 * xmlValidNormalizeAttributeValue:
 * @doc:  the document
 * @elem:  the parent
 * @name:  the attribute name
 * @value:  the attribute value
 *
 * Does the validation related extra step of the normalization of attribute
 * values:
 *
 * If the declared value is not CDATA, then the XML processor must further
 * process the normalized attribute value by discarding any leading and
 * trailing space (#x20) characters, and by replacing sequences of space
 * (#x20) characters by single space (#x20) character.
 *
 * returns a new normalized string if normalization is needed, NULL otherwise
 *      the caller must free the returned value.
 */

xmlChar *
xmlValidNormalizeAttributeValue(xmlDocPtr doc, xmlNodePtr elem,
			        const xmlChar *name, const xmlChar *value) {
    xmlChar *ret, *dst;
    const xmlChar *src;
    xmlAttributePtr attrDecl = NULL;

    if (doc == NULL) return(NULL);
    if (elem == NULL) return(NULL);
    if (name == NULL) return(NULL);
    if (value == NULL) return(NULL);

    if ((elem->ns != NULL) && (elem->ns->prefix != NULL)) {
	xmlChar qname[500];
#ifdef HAVE_SNPRINTF
	snprintf((char *) qname, sizeof(qname), "%s:%s",
		 elem->ns->prefix, elem->name);
#else
	sprintf((char *) qname, "%s:%s", elem->ns->prefix, elem->name);
#endif
        qname[sizeof(qname) - 1] = 0;
	attrDecl = xmlGetDtdAttrDesc(doc->intSubset, qname, name);
	if ((attrDecl == NULL) && (doc->extSubset != NULL))
	    attrDecl = xmlGetDtdAttrDesc(doc->extSubset, qname, name);
    }
    attrDecl = xmlGetDtdAttrDesc(doc->intSubset, elem->name, name);
    if ((attrDecl == NULL) && (doc->extSubset != NULL))
	attrDecl = xmlGetDtdAttrDesc(doc->extSubset, elem->name, name);

    if (attrDecl == NULL)
	return(NULL);
    if (attrDecl->atype == XML_ATTRIBUTE_CDATA)
	return(NULL);

    ret = xmlStrdup(value);
    if (ret == NULL)
	return(NULL);
    src = value;
    dst = ret;
    while (*src == 0x20) src++;
    while (*src != 0) {
	if (*src == 0x20) {
	    while (*src == 0x20) src++;
	    if (*src != 0)
		*dst++ = 0x20;
	} else {
	    *dst++ = *src++;
	}
    }
    *dst = 0;
    return(ret);
}

void
xmlValidateAttributeIdCallback(xmlAttributePtr attr, int *count,
	                       const xmlChar* name) {
    if (attr->atype == XML_ATTRIBUTE_ID) (*count)++;
}

/**
 * xmlValidateAttributeDecl:
 * @ctxt:  the validation context
 * @doc:  a document instance
 * @attr:  an attribute definition
 *
 * Try to validate a single attribute definition
 * basically it does the following checks as described by the
 * XML-1.0 recommendation:
 *  - [ VC: Attribute Default Legal ]
 *  - [ VC: Enumeration ]
 *  - [ VC: ID Attribute Default ]
 *
 * The ID/IDREF uniqueness and matching are done separately
 *
 * returns 1 if valid or 0 otherwise
 */

int
xmlValidateAttributeDecl(xmlValidCtxtPtr ctxt, xmlDocPtr doc,
                         xmlAttributePtr attr) {
    int ret = 1;
    int val;
    CHECK_DTD;
    if(attr == NULL) return(1);
    
    /* Attribute Default Legal */
    /* Enumeration */
    if (attr->defaultValue != NULL) {
	val = xmlValidateAttributeValue(attr->atype, attr->defaultValue);
	if (val == 0) {
	    VERROR(ctxt->userData, 
	       "Syntax of default value for attribute %s on %s is not valid\n",
	           attr->name, attr->elem);
	}
        ret &= val;
    }

    /* ID Attribute Default */
    if ((attr->atype == XML_ATTRIBUTE_ID)&&
        (attr->def != XML_ATTRIBUTE_IMPLIED) &&
	(attr->def != XML_ATTRIBUTE_REQUIRED)) {
	VERROR(ctxt->userData, 
          "ID attribute %s on %s is not valid must be #IMPLIED or #REQUIRED\n",
	       attr->name, attr->elem);
	ret = 0;
    }

    /* One ID per Element Type */
    if (attr->atype == XML_ATTRIBUTE_ID) {
        int nbId;

	/* the trick is taht we parse DtD as their own internal subset */
        xmlElementPtr elem = xmlGetDtdElementDesc(doc->intSubset,
	                                          attr->elem);
	if (elem != NULL) {
	    nbId = xmlScanIDAttributeDecl(NULL, elem);
	} else {
	    xmlAttributeTablePtr table;

	    /*
	     * The attribute may be declared in the internal subset and the
	     * element in the external subset.
	     */
	    nbId = 0;
	    table = (xmlAttributeTablePtr) doc->intSubset->attributes;
	    xmlHashScan3(table, NULL, NULL, attr->elem, (xmlHashScanner)
		         xmlValidateAttributeIdCallback, &nbId);
	}
	if (nbId > 1) {
	    VERROR(ctxt->userData, 
       "Element %s has %d ID attribute defined in the internal subset : %s\n",
		   attr->elem, nbId, attr->name);
	} else if (doc->extSubset != NULL) {
	    int extId = 0;
	    elem = xmlGetDtdElementDesc(doc->extSubset, attr->elem);
	    if (elem != NULL) {
		extId = xmlScanIDAttributeDecl(NULL, elem);
	    }
	    if (extId > 1) {
		VERROR(ctxt->userData, 
       "Element %s has %d ID attribute defined in the external subset : %s\n",
		       attr->elem, extId, attr->name);
	    } else if (extId + nbId > 1) {
		VERROR(ctxt->userData, 
"Element %s has ID attributes defined in the internal and external subset : %s\n",
		       attr->elem, attr->name);
	    }
	}
    }

    /* Validity Constraint: Enumeration */
    if ((attr->defaultValue != NULL) && (attr->tree != NULL)) {
        xmlEnumerationPtr tree = attr->tree;
	while (tree != NULL) {
	    if (xmlStrEqual(tree->name, attr->defaultValue)) break;
	    tree = tree->next;
	}
	if (tree == NULL) {
	    VERROR(ctxt->userData, 
"Default value \"%s\" for attribute %s on %s is not among the enumerated set\n",
		   attr->defaultValue, attr->name, attr->elem);
	    ret = 0;
	}
    }

    return(ret);
}

/**
 * xmlValidateElementDecl:
 * @ctxt:  the validation context
 * @doc:  a document instance
 * @elem:  an element definition
 *
 * Try to validate a single element definition
 * basically it does the following checks as described by the
 * XML-1.0 recommendation:
 *  - [ VC: One ID per Element Type ]
 *  - [ VC: No Duplicate Types ]
 *  - [ VC: Unique Element Type Declaration ]
 *
 * returns 1 if valid or 0 otherwise
 */

int
xmlValidateElementDecl(xmlValidCtxtPtr ctxt, xmlDocPtr doc,
                       xmlElementPtr elem) {
    int ret = 1;
    xmlElementPtr tst;

    CHECK_DTD;
    
    if (elem == NULL) return(1);

    /* No Duplicate Types */
    if (elem->etype == XML_ELEMENT_TYPE_MIXED) {
	xmlElementContentPtr cur, next;
        const xmlChar *name;

	cur = elem->content;
	while (cur != NULL) {
	    if (cur->type != XML_ELEMENT_CONTENT_OR) break;
	    if (cur->c1 == NULL) break;
	    if (cur->c1->type == XML_ELEMENT_CONTENT_ELEMENT) {
		name = cur->c1->name;
		next = cur->c2;
		while (next != NULL) {
		    if (next->type == XML_ELEMENT_CONTENT_ELEMENT) {
		        if (xmlStrEqual(next->name, name)) {
			    VERROR(ctxt->userData, 
		   "Definition of %s has duplicate references of %s\n",
				   elem->name, name);
			    ret = 0;
			}
			break;
		    }
		    if (next->c1 == NULL) break;
		    if (next->c1->type != XML_ELEMENT_CONTENT_ELEMENT) break;
		    if (xmlStrEqual(next->c1->name, name)) {
			VERROR(ctxt->userData, 
	       "Definition of %s has duplicate references of %s\n",
			       elem->name, name);
			ret = 0;
		    }
		    next = next->c2;
		}
	    }
	    cur = cur->c2;
	}
    }

    /* VC: Unique Element Type Declaration */
    tst = xmlGetDtdElementDesc(doc->intSubset, elem->name);
    if ((tst != NULL ) && (tst != elem)) {
	VERROR(ctxt->userData, "Redefinition of element %s\n",
	       elem->name);
	ret = 0;
    }
    tst = xmlGetDtdElementDesc(doc->extSubset, elem->name);
    if ((tst != NULL ) && (tst != elem)) {
	VERROR(ctxt->userData, "Redefinition of element %s\n",
	       elem->name);
	ret = 0;
    }

    /* One ID per Element Type */
    if (xmlScanIDAttributeDecl(ctxt, elem) > 1) {
	ret = 0;
    }
    return(ret);
}

/**
 * xmlValidateOneAttribute:
 * @ctxt:  the validation context
 * @doc:  a document instance
 * @elem:  an element instance
 * @attr:  an attribute instance
 * @value:  the attribute value (without entities processing)
 *
 * Try to validate a single attribute for an element
 * basically it does the following checks as described by the
 * XML-1.0 recommendation:
 *  - [ VC: Attribute Value Type ]
 *  - [ VC: Fixed Attribute Default ]
 *  - [ VC: Entity Name ]
 *  - [ VC: Name Token ]
 *  - [ VC: ID ]
 *  - [ VC: IDREF ]
 *  - [ VC: Entity Name ]
 *  - [ VC: Notation Attributes ]
 *
 * The ID/IDREF uniqueness and matching are done separately
 *
 * returns 1 if valid or 0 otherwise
 */

int
xmlValidateOneAttribute(xmlValidCtxtPtr ctxt, xmlDocPtr doc,
                        xmlNodePtr elem, xmlAttrPtr attr, const xmlChar *value) {
    /* xmlElementPtr elemDecl; */
    xmlAttributePtr attrDecl =  NULL;
    int val;
    int ret = 1;

    CHECK_DTD;
    if ((elem == NULL) || (elem->name == NULL)) return(0);
    if ((attr == NULL) || (attr->name == NULL)) return(0);

    if ((elem->ns != NULL) && (elem->ns->prefix != NULL)) {
	xmlChar qname[500];
#ifdef HAVE_SNPRINTF
	snprintf((char *) qname, sizeof(qname), "%s:%s",
		 elem->ns->prefix, elem->name);
#else
	sprintf((char *) qname, "%s:%s", elem->ns->prefix, elem->name);
#endif
        qname[sizeof(qname) - 1] = 0;
	if (attr->ns != NULL) {
	    attrDecl = xmlGetDtdQAttrDesc(doc->intSubset, qname,
		                          attr->name, attr->ns->prefix);
	    if ((attrDecl == NULL) && (doc->extSubset != NULL))
		attrDecl = xmlGetDtdQAttrDesc(doc->extSubset, qname,
					      attr->name, attr->ns->prefix);
	} else {
	    attrDecl = xmlGetDtdAttrDesc(doc->intSubset, qname, attr->name);
	    if ((attrDecl == NULL) && (doc->extSubset != NULL))
		attrDecl = xmlGetDtdAttrDesc(doc->extSubset,
					     qname, attr->name);
	}
    }
    if (attrDecl == NULL) {
	if (attr->ns != NULL) {
	    attrDecl = xmlGetDtdQAttrDesc(doc->intSubset, elem->name,
		                          attr->name, attr->ns->prefix);
	    if ((attrDecl == NULL) && (doc->extSubset != NULL))
		attrDecl = xmlGetDtdQAttrDesc(doc->extSubset, elem->name,
					      attr->name, attr->ns->prefix);
	} else {
	    attrDecl = xmlGetDtdAttrDesc(doc->intSubset,
		                         elem->name, attr->name);
	    if ((attrDecl == NULL) && (doc->extSubset != NULL))
		attrDecl = xmlGetDtdAttrDesc(doc->extSubset,
					     elem->name, attr->name);
	}
    }


    /* Validity Constraint: Attribute Value Type */
    if (attrDecl == NULL) {
	VERROR(ctxt->userData,
	       "No declaration for attribute %s on element %s\n",
	       attr->name, elem->name);
	return(0);
    }
    attr->atype = attrDecl->atype;

    val = xmlValidateAttributeValue(attrDecl->atype, value);
    if (val == 0) {
	VERROR(ctxt->userData, 
	   "Syntax of value for attribute %s on %s is not valid\n",
	       attr->name, elem->name);
        ret = 0;
    }

    /* Validity constraint: Fixed Attribute Default */
    if (attrDecl->def == XML_ATTRIBUTE_FIXED) {
	if (!xmlStrEqual(value, attrDecl->defaultValue)) {
	    VERROR(ctxt->userData, 
	   "Value for attribute %s on %s is differnt from default \"%s\"\n",
		   attr->name, elem->name, attrDecl->defaultValue);
	    ret = 0;
	}
    }

    /* Validity Constraint: ID uniqueness */
    if (attrDecl->atype == XML_ATTRIBUTE_ID) {
        if (xmlAddID(ctxt, doc, value, attr) == NULL)
	    ret = 0;
    }

    if ((attrDecl->atype == XML_ATTRIBUTE_IDREF) ||
	(attrDecl->atype == XML_ATTRIBUTE_IDREFS)) {
        if (xmlAddRef(ctxt, doc, value, attr) == NULL)
	    ret = 0;
    }

    /* Validity Constraint: Notation Attributes */
    if (attrDecl->atype == XML_ATTRIBUTE_NOTATION) {
        xmlEnumerationPtr tree = attrDecl->tree;
        xmlNotationPtr nota;

        /* First check that the given NOTATION was declared */
	nota = xmlGetDtdNotationDesc(doc->intSubset, value);
	if (nota == NULL)
	    nota = xmlGetDtdNotationDesc(doc->extSubset, value);
	
	if (nota == NULL) {
	    VERROR(ctxt->userData, 
       "Value \"%s\" for attribute %s on %s is not a declared Notation\n",
		   value, attr->name, elem->name);
	    ret = 0;
        }

	/* Second, verify that it's among the list */
	while (tree != NULL) {
	    if (xmlStrEqual(tree->name, value)) break;
	    tree = tree->next;
	}
	if (tree == NULL) {
	    VERROR(ctxt->userData, 
"Value \"%s\" for attribute %s on %s is not among the enumerated notations\n",
		   value, attr->name, elem->name);
	    ret = 0;
	}
    }

    /* Validity Constraint: Enumeration */
    if (attrDecl->atype == XML_ATTRIBUTE_ENUMERATION) {
        xmlEnumerationPtr tree = attrDecl->tree;
	while (tree != NULL) {
	    if (xmlStrEqual(tree->name, value)) break;
	    tree = tree->next;
	}
	if (tree == NULL) {
	    VERROR(ctxt->userData, 
       "Value \"%s\" for attribute %s on %s is not among the enumerated set\n",
		   value, attr->name, elem->name);
	    ret = 0;
	}
    }

    /* Fixed Attribute Default */
    if ((attrDecl->def == XML_ATTRIBUTE_FIXED) &&
        (!xmlStrEqual(attrDecl->defaultValue, value))) {
	VERROR(ctxt->userData, 
	   "Value for attribute %s on %s must be \"%s\"\n",
	       attr->name, elem->name, attrDecl->defaultValue);
        ret = 0;
    }

    /* Extra check for the attribute value */
    ret &= xmlValidateAttributeValue2(ctxt, doc, attr->name,
				      attrDecl->atype, value);

    return(ret);
}

/* Find the next XML_ELEMENT_NODE, subject to the content constraints.
 * Return -1 if we found something unexpected, or 1 otherwise.
 */

static int
xmlValidateFindNextElement(xmlValidCtxtPtr ctxt, xmlNodePtr *child,
                           xmlElementContentPtr cont)
{
  while (*child && (*child)->type != XML_ELEMENT_NODE) {
    switch ((*child)->type) {
      /*
       * If there is an entity declared and it's not empty
       * Push the current node on the stack and process with the
       * entity content.
       */
      case XML_ENTITY_REF_NODE:
        if (((*child)->children != NULL) &&
            ((*child)->children->children != NULL)) {
          nodeVPush(ctxt, *child);
          *child = (*child)->children->children;
          continue;
        }
        break;

      /* These things are ignored (skipped) during validation.  */
      case XML_PI_NODE:
      case XML_COMMENT_NODE:
      case XML_XINCLUDE_START:
      case XML_XINCLUDE_END:
        break;

      case XML_TEXT_NODE:
        if (xmlIsBlankNode(*child)
            && (cont->type == XML_ELEMENT_CONTENT_ELEMENT
                || cont->type == XML_ELEMENT_CONTENT_SEQ
                || cont->type == XML_ELEMENT_CONTENT_OR))
          break;
        return -1;

      default:
        return -1;
    }
    *child = (*child)->next;
  }

  return 1;
}

int xmlValidateElementTypeElement(xmlValidCtxtPtr ctxt, xmlNodePtr *child,
				  xmlElementContentPtr cont);

/**
 * xmlValidateElementTypeExpr:
 * @ctxt:  the validation context
 * @child:  pointer to the child list
 * @cont:  pointer to the content declaration
 *
 * Try to validate the content of an element of type element
 * but don't handle the occurence factor
 *
 * returns 1 if valid or 0 and -1 if PCDATA stuff is found,
 *         also update child value in-situ.
 */

int
xmlValidateElementTypeExpr(xmlValidCtxtPtr ctxt, xmlNodePtr *child,
			   xmlElementContentPtr cont) {
    xmlNodePtr cur;
    int ret = 1;

    if (cont == NULL) return(-1);
    DEBUG_VALID_STATE(*child, cont)
    ret = xmlValidateFindNextElement(ctxt, child, cont);
    if (ret < 0)
	    return(-1);
    DEBUG_VALID_STATE(*child, cont)
    switch (cont->type) {
	case XML_ELEMENT_CONTENT_PCDATA:
	    if (*child == NULL) return(0);
	    if ((*child)->type == XML_TEXT_NODE) return(1);
	    return(0);
	case XML_ELEMENT_CONTENT_ELEMENT:
	    if (*child == NULL) return(0);
	    ret = (xmlStrEqual((*child)->name, cont->name));
	    if (ret == 1) {
		while ((*child)->next == NULL) {
                    if (((*child)->parent != NULL) &&
			((*child)->parent->type == XML_ENTITY_DECL)) {
			*child = nodeVPop(ctxt);
		    } else
			break;
		}
	        *child = (*child)->next;
	    }
	    return(ret);
	case XML_ELEMENT_CONTENT_OR:
	    cur = *child;
	    ret = xmlValidateElementTypeElement(ctxt, child, cont->c1);
	    if (ret == -1) return(-1);
	    if (ret == 1) {
		 return(1);
	    }
	    /* rollback and retry the other path */
	    *child = cur;
	    ret = xmlValidateElementTypeElement(ctxt, child, cont->c2);
	    if (ret == -1) return(-1);
	    if (ret == 0) {
		*child = cur;
		return(0);
	    }
	    return(1);
	case XML_ELEMENT_CONTENT_SEQ:
	    cur = *child;
	    ret = xmlValidateElementTypeElement(ctxt, child, cont->c1);
	    if (ret == -1) return(-1);
	    if (ret == 0) {
		*child = cur;
		return(0);
	    }
	    ret = xmlValidateElementTypeElement(ctxt, child, cont->c2);
	    if (ret == -1) return(-1);
	    if (ret == 0) {
		*child = cur;
		return(0);
	    }
	    return(1);
    }
    return(ret);
}

/**
 * xmlValidateElementTypeElement:
 * @ctxt:  the validation context
 * @child:  pointer to the child list
 * @cont:  pointer to the content declaration
 *
 * Try to validate the content of an element of type element
 * yeah, Yet Another Regexp Implementation, and recursive
 *
 * returns 1 if valid or 0 and -1 if PCDATA stuff is found,
 *         also update child and content values in-situ.
 */

int
xmlValidateElementTypeElement(xmlValidCtxtPtr ctxt, xmlNodePtr *child,
			      xmlElementContentPtr cont) {
    xmlNodePtr cur;
    int ret;

    if (cont == NULL) return(-1);

    DEBUG_VALID_STATE(*child, cont)
    ret = xmlValidateFindNextElement(ctxt, child, cont);
    if (ret < 0)
	    return(-1);
    DEBUG_VALID_STATE(*child, cont)
    cur = *child;
    ret = xmlValidateElementTypeExpr(ctxt, child, cont);
    if (ret == -1) return(-1);
    switch (cont->ocur) {
	case XML_ELEMENT_CONTENT_ONCE:
	    if (ret == 1) {
		/* skip ignorable elems */
		while ((*child != NULL) &&
		       ((*child)->type == XML_PI_NODE
                        || (*child)->type == XML_COMMENT_NODE
                        || (*child)->type == XML_XINCLUDE_START
                        || (*child)->type == XML_XINCLUDE_END)) {
		    while ((*child)->next == NULL) {
			if (((*child)->parent != NULL) &&
			    ((*child)->parent->type == XML_ENTITY_REF_NODE)) {
			    *child = (*child)->parent;
			} else
			    break;
		    }
		    *child = (*child)->next;
		}
		return(1);
	    }
	    *child = cur;
	    return(0);
	case XML_ELEMENT_CONTENT_OPT:
	    if (ret == 0) {
		*child = cur;
	        return(1);
	    }
	    break;
	case XML_ELEMENT_CONTENT_MULT:
	    if (ret == 0) {
		*child = cur;
	        break;
	    }
	    /* no break on purpose */
	case XML_ELEMENT_CONTENT_PLUS:
	    if (ret == 0) {
		*child = cur;
	        return(0);
	    }
	    if (ret == -1) return(-1);
	    cur = *child;
	    do {
		if (*child == NULL)
		    break; /* while */
		if ((*child)->type == XML_TEXT_NODE
                    && xmlIsBlankNode(*child)) {
		    *child = (*child)->next;
		    continue;
		}
		ret = xmlValidateElementTypeExpr(ctxt, child, cont);
		if (ret == 1)
		    cur = *child;
	    } while (ret == 1);
	    if (ret == -1) return(-1);
	    *child = cur;
	    break;
    }

    return xmlValidateFindNextElement(ctxt, child, cont);
}

/**
 * xmlSprintfElementChilds:
 * @buf:  an output buffer
 * @content:  An element
 * @glob: 1 if one must print the englobing parenthesis, 0 otherwise
 *
 * This will dump the list of childs to the buffer
 * Intended just for the debug routine
 */
void
xmlSprintfElementChilds(char *buf, xmlNodePtr node, int glob) {
    xmlNodePtr cur;

    if (node == NULL) return;
    if (glob) strcat(buf, "(");
    cur = node->children;
    while (cur != NULL) {
        switch (cur->type) {
            case XML_ELEMENT_NODE:
	         strcat(buf, (char *) cur->name);
		 if (cur->next != NULL)
		     strcat(buf, " ");
		 break;
            case XML_TEXT_NODE:
		 if (xmlIsBlankNode(cur))
		     break;
            case XML_CDATA_SECTION_NODE:
            case XML_ENTITY_REF_NODE:
	         strcat(buf, "CDATA");
		 if (cur->next != NULL)
		     strcat(buf, " ");
		 break;
            case XML_ATTRIBUTE_NODE:
            case XML_DOCUMENT_NODE:
#ifdef LIBXML_SGML_ENABLED
	    case XML_SGML_DOCUMENT_NODE:
#endif
	    case XML_HTML_DOCUMENT_NODE:
            case XML_DOCUMENT_TYPE_NODE:
            case XML_DOCUMENT_FRAG_NODE:
            case XML_NOTATION_NODE:
	    case XML_NAMESPACE_DECL:
	         strcat(buf, "???");
		 if (cur->next != NULL)
		     strcat(buf, " ");
		 break;
            case XML_ENTITY_NODE:
            case XML_PI_NODE:
            case XML_DTD_NODE:
            case XML_COMMENT_NODE:
	    case XML_ELEMENT_DECL:
	    case XML_ATTRIBUTE_DECL:
	    case XML_ENTITY_DECL:
	    case XML_XINCLUDE_START:
	    case XML_XINCLUDE_END:
		 break;
	}
	cur = cur->next;
    }
    if (glob) strcat(buf, ")");
}


/**
 * xmlValidateOneElement:
 * @ctxt:  the validation context
 * @doc:  a document instance
 * @elem:  an element instance
 *
 * Try to validate a single element and it's attributes,
 * basically it does the following checks as described by the
 * XML-1.0 recommendation:
 *  - [ VC: Element Valid ]
 *  - [ VC: Required Attribute ]
 * Then call xmlValidateOneAttribute() for each attribute present.
 *
 * The ID/IDREF checkings are done separately
 *
 * returns 1 if valid or 0 otherwise
 */

int
xmlValidateOneElement(xmlValidCtxtPtr ctxt, xmlDocPtr doc,
                      xmlNodePtr elem) {
    xmlElementPtr elemDecl = NULL;
    xmlElementContentPtr cont;
    xmlAttributePtr attr;
    xmlNodePtr child;
    int ret = 1;
    const xmlChar *name;

    CHECK_DTD;

    if (elem == NULL) return(0);
    if (elem->type == XML_TEXT_NODE) {
    }
    switch (elem->type) {
        case XML_ATTRIBUTE_NODE:
	    VERROR(ctxt->userData, 
		   "Attribute element not expected here\n");
	    return(0);
        case XML_TEXT_NODE:
	    if (elem->children != NULL) {
		VERROR(ctxt->userData, "Text element has childs !\n");
		return(0);
	    }
	    if (elem->properties != NULL) {
		VERROR(ctxt->userData, "Text element has attributes !\n");
		return(0);
	    }
	    if (elem->ns != NULL) {
		VERROR(ctxt->userData, "Text element has namespace !\n");
		return(0);
	    }
	    if (elem->nsDef != NULL) {
		VERROR(ctxt->userData, 
		       "Text element carries namespace definitions !\n");
		return(0);
	    }
	    if (elem->content == NULL) {
		VERROR(ctxt->userData, 
		       "Text element has no content !\n");
		return(0);
	    }
	    return(1);
        case XML_XINCLUDE_START:
        case XML_XINCLUDE_END:
            return(1);
        case XML_CDATA_SECTION_NODE:
        case XML_ENTITY_REF_NODE:
        case XML_PI_NODE:
        case XML_COMMENT_NODE:
	    return(1);
        case XML_ENTITY_NODE:
	    VERROR(ctxt->userData, 
		   "Entity element not expected here\n");
	    return(0);
        case XML_NOTATION_NODE:
	    VERROR(ctxt->userData, 
		   "Notation element not expected here\n");
	    return(0);
        case XML_DOCUMENT_NODE:
        case XML_DOCUMENT_TYPE_NODE:
        case XML_DOCUMENT_FRAG_NODE:
	    VERROR(ctxt->userData, 
		   "Document element not expected here\n");
	    return(0);
        case XML_HTML_DOCUMENT_NODE:
	    VERROR(ctxt->userData, 
		   "\n");
	    return(0);
        case XML_ELEMENT_NODE:
	    break;
	default:
	    VERROR(ctxt->userData, 
		   "unknown element type %d\n", elem->type);
	    return(0);
    }
    if (elem->name == NULL) return(0);

    /*
     * Fetch the declaration for the qualified name
     */
    if ((elem->ns != NULL) && (elem->ns->prefix != NULL)) {
	elemDecl = xmlGetDtdQElementDesc(doc->intSubset,
		                         elem->name, elem->ns->prefix);
	if ((elemDecl == NULL) && (doc->extSubset != NULL))
	    elemDecl = xmlGetDtdQElementDesc(doc->extSubset,
		                             elem->name, elem->ns->prefix);
    }

    /*
     * Fetch the declaration for the non qualified name
     */
    if (elemDecl == NULL) {
	elemDecl = xmlGetDtdElementDesc(doc->intSubset, elem->name);
	if ((elemDecl == NULL) && (doc->extSubset != NULL))
	    elemDecl = xmlGetDtdElementDesc(doc->extSubset, elem->name);
    }
    if (elemDecl == NULL) {
	VERROR(ctxt->userData, "No declaration for element %s\n",
	       elem->name);
	return(0);
    }

    /* Check taht the element content matches the definition */
    switch (elemDecl->etype) {
        case XML_ELEMENT_TYPE_EMPTY:
	    if (elem->children != NULL) {
		VERROR(ctxt->userData,
	       "Element %s was declared EMPTY this one has content\n",
	               elem->name);
		ret = 0;
	    }
	    break;
        case XML_ELEMENT_TYPE_ANY:
	    /* I don't think anything is required then */
	    break;
        case XML_ELEMENT_TYPE_MIXED:
	    /* Hum, this start to get messy */
	    child = elem->children;
	    while (child != NULL) {
	        if (child->type == XML_ELEMENT_NODE) {
		    name = child->name;
		    if ((child->ns != NULL) && (child->ns->prefix != NULL)) {
			xmlChar qname[500];
#ifdef HAVE_SNPRINTF
			snprintf((char *) qname, sizeof(qname), "%s:%s",
				 child->ns->prefix, child->name);
#else
			sprintf((char *) qname, "%s:%s",
                                 child->ns->prefix, child->name);
#endif
                        qname[sizeof(qname) - 1] = 0;
			cont = elemDecl->content;
			while (cont != NULL) {
			    if (cont->type == XML_ELEMENT_CONTENT_ELEMENT) {
				if (xmlStrEqual(cont->name, qname)) break;
			    } else if ((cont->type == XML_ELEMENT_CONTENT_OR) &&
			       (cont->c1 != NULL) &&
			       (cont->c1->type == XML_ELEMENT_CONTENT_ELEMENT)){
				if (xmlStrEqual(cont->c1->name, qname)) break;
			    } else if ((cont->type != XML_ELEMENT_CONTENT_OR) ||
				(cont->c1 == NULL) ||
				(cont->c1->type != XML_ELEMENT_CONTENT_PCDATA)){
				/* Internal error !!! */
				xmlGenericError(xmlGenericErrorContext,
					"Internal: MIXED struct bad\n");
				break;
			    }
			    cont = cont->c2;
			}
			if (cont != NULL)
			    goto child_ok;
		    }
		    cont = elemDecl->content;
		    while (cont != NULL) {
		        if (cont->type == XML_ELEMENT_CONTENT_ELEMENT) {
			    if (xmlStrEqual(cont->name, name)) break;
			} else if ((cont->type == XML_ELEMENT_CONTENT_OR) &&
			   (cont->c1 != NULL) &&
			   (cont->c1->type == XML_ELEMENT_CONTENT_ELEMENT)) {
			    if (xmlStrEqual(cont->c1->name, name)) break;
			} else if ((cont->type != XML_ELEMENT_CONTENT_OR) ||
			    (cont->c1 == NULL) ||
			    (cont->c1->type != XML_ELEMENT_CONTENT_PCDATA)) {
			    /* Internal error !!! */
			    xmlGenericError(xmlGenericErrorContext,
				    "Internal: MIXED struct bad\n");
			    break;
			}
			cont = cont->c2;
		    }
		    if (cont == NULL) {
			VERROR(ctxt->userData,
	       "Element %s is not declared in %s list of possible childs\n",
			       name, elem->name);
			ret = 0;
		    }
		}
child_ok:
	        child = child->next;
	    }
	    break;
        case XML_ELEMENT_TYPE_ELEMENT:
	    child = elem->children;
	    cont = elemDecl->content;
	    ret = xmlValidateElementTypeElement(ctxt, &child, cont);
	    while ((child != NULL) && (child->type == XML_TEXT_NODE) &&
		(xmlIsBlankNode(child))) {
		child = child->next;
		continue;
	    }
	    if ((ret == 0) || (child != NULL)) {
	        char expr[1000];
	        char list[2000];

		expr[0] = 0;
		xmlSprintfElementContent(expr, cont, 1);
		list[0] = 0;
		xmlSprintfElementChilds(list, elem, 1);

		VERROR(ctxt->userData,
	   "Element %s content doesn't follow the Dtd\nExpecting %s, got %s\n",
	               elem->name, expr, list);
		ret = 0;
	    }
	    break;
    }

    /* [ VC: Required Attribute ] */
    attr = elemDecl->attributes;
    while (attr != NULL) {
	if (attr->def == XML_ATTRIBUTE_REQUIRED) {
	    xmlAttrPtr attrib;
	    int qualified = -1;
	    
	    attrib = elem->properties;
	    while (attrib != NULL) {
		if (xmlStrEqual(attrib->name, attr->name)) {
		    if (attr->prefix != NULL) {
		        xmlNsPtr nameSpace = attrib->ns;

			if (nameSpace == NULL)
			    nameSpace = elem->ns;
			/*
			 * qualified names handling is problematic, having a
			 * different prefix should be possible but DTDs don't
			 * allow to define the URI instead of the prefix :-(
			 */
			if (nameSpace == NULL) {
			    if (qualified < 0) 
				qualified = 0;
	    		} else if (!xmlStrEqual(nameSpace->prefix, attr->prefix)) {
			    if (qualified < 1) 
				qualified = 1;
			} else
			    goto found;
		    } else {
		        /*
			 * We should allow applications to define namespaces
			 * for their application even if the DTD doesn't 
			 * carry one, otherwise, basically we would always
			 * break.
			 */
			goto found;
		    }
		}
		attrib = attrib->next;
	    }
	    if (qualified == -1) {
		if (attr->prefix == NULL) {
		    VERROR(ctxt->userData,
		       "Element %s doesn't carry attribute %s\n",
			   elem->name, attr->name);
		    ret = 0;
	        } else {
		    VERROR(ctxt->userData,
		       "Element %s doesn't carry attribute %s:%s\n",
			   elem->name, attr->prefix,attr->name);
		    ret = 0;
		}
	    } else if (qualified == 0) {
		VWARNING(ctxt->userData,
		   "Element %s required attribute %s:%s has no prefix\n",
		       elem->name, attr->prefix,attr->name);
	    } else if (qualified == 1) {
		VWARNING(ctxt->userData,
		   "Element %s required attribute %s:%s has different prefix\n",
		       elem->name, attr->prefix,attr->name);
	    }
	}
found:	    
        attr = attr->nexth;
    }
    return(ret);
}

/**
 * xmlValidateRoot:
 * @ctxt:  the validation context
 * @doc:  a document instance
 *
 * Try to validate a the root element
 * basically it does the following check as described by the
 * XML-1.0 recommendation:
 *  - [ VC: Root Element Type ]
 * it doesn't try to recurse or apply other check to the element
 *
 * returns 1 if valid or 0 otherwise
 */

int
xmlValidateRoot(xmlValidCtxtPtr ctxt, xmlDocPtr doc) {
    xmlNodePtr root;
    if (doc == NULL) return(0);

    root = xmlDocGetRootElement(doc);
    if ((root == NULL) || (root->name == NULL)) {
	VERROR(ctxt->userData, "Not valid: no root element\n");
        return(0);
    }

    /*
     * When doing post validation against a separate DTD, those may
     * no internal subset has been generated
     */
    if ((doc->intSubset != NULL) &&
	(doc->intSubset->name != NULL)) {
	/*
	 * Check first the document root against the NQName
	 */
	if (!xmlStrEqual(doc->intSubset->name, root->name)) {
	    if ((root->ns != NULL) && (root->ns->prefix != NULL)) {
		xmlChar qname[500];
#ifdef HAVE_SNPRINTF
		snprintf((char *) qname, sizeof(qname), "%s:%s",
			 root->ns->prefix, root->name);
#else
		sprintf((char *) qname, "%s:%s", root->ns->prefix, root->name);
#endif
		qname[sizeof(qname) - 1] = 0;
		if (xmlStrEqual(doc->intSubset->name, qname))
		    goto name_ok;
	    } 
	    if ((xmlStrEqual(doc->intSubset->name, BAD_CAST "HTML")) &&
		(xmlStrEqual(root->name, BAD_CAST "html")))
		goto name_ok;
	    VERROR(ctxt->userData,
		   "Not valid: root and DtD name do not match '%s' and '%s'\n",
		   root->name, doc->intSubset->name);
	    return(0);
	    
	}
    }
name_ok:
    return(1);
}


/**
 * xmlValidateElement:
 * @ctxt:  the validation context
 * @doc:  a document instance
 * @elem:  an element instance
 *
 * Try to validate the subtree under an element 
 *
 * returns 1 if valid or 0 otherwise
 */

int
xmlValidateElement(xmlValidCtxtPtr ctxt, xmlDocPtr doc, xmlNodePtr elem) {
    xmlNodePtr child;
    xmlAttrPtr attr;
    xmlChar *value;
    int ret = 1;

    if (elem == NULL) return(0);

    /*
     * XInclude elements were added after parsing in the infoset,
     * they don't really mean anything validation wise.
     */
    if ((elem->type == XML_XINCLUDE_START) ||
	(elem->type == XML_XINCLUDE_END))
	return(1);

    CHECK_DTD;

    ret &= xmlValidateOneElement(ctxt, doc, elem);
    attr = elem->properties;
    while(attr != NULL) {
        value = xmlNodeListGetString(doc, attr->children, 0);
	ret &= xmlValidateOneAttribute(ctxt, doc, elem, attr, value);
	if (value != NULL)
	    xmlFree(value);
	attr= attr->next;
    }
    child = elem->children;
    while (child != NULL) {
        ret &= xmlValidateElement(ctxt, doc, child);
        child = child->next;
    }

    return(ret);
}


void
xmlValidateCheckRefCallback(xmlRefPtr ref, xmlValidCtxtPtr ctxt,
	                   const xmlChar *name) {
    xmlAttrPtr id;
    xmlAttrPtr attr;

    if (ref == NULL)
	return;
    attr = ref->attr;
    if (attr == NULL)
	return;
    if (attr->atype == XML_ATTRIBUTE_IDREF) {
	id = xmlGetID(ctxt->doc, name);
	if (id == NULL) {
	    VERROR(ctxt->userData, 
	       "IDREF attribute %s reference an unknown ID \"%s\"\n",
		   attr->name, name);
	    ctxt->valid = 0;
	}
    } else if (attr->atype == XML_ATTRIBUTE_IDREFS) {
	xmlChar *dup, *str = NULL, *cur, save;

	dup = xmlStrdup(name);
	if (dup == NULL) {
	    ctxt->valid = 0;
	    return;
	}
	cur = dup;
	while (*cur != 0) {
	    str = cur;
	    while ((*cur != 0) && (!IS_BLANK(*cur))) cur++;
	    save = *cur;
	    *cur = 0;
	    id = xmlGetID(ctxt->doc, str);
	    if (id == NULL) {
		VERROR(ctxt->userData, 
	       "IDREFS attribute %s reference an unknown ID \"%s\"\n",
		       attr->name, str);
		ctxt->valid = 0;
	    }
	    if (save == 0)
		break;
	    *cur = save;
	    while (IS_BLANK(*cur)) cur++;
	}
	xmlFree(dup);
    }
}

/**
 * xmlValidateDocumentFinal:
 * @ctxt:  the validation context
 * @doc:  a document instance
 *
 * Does the final step for the document validation once all the
 * incremental validation steps have been completed
 *
 * basically it does the following checks described by the XML Rec
 * 
 *
 * returns 1 if valid or 0 otherwise
 */

int
xmlValidateDocumentFinal(xmlValidCtxtPtr ctxt, xmlDocPtr doc) {
    xmlRefTablePtr table;

    if (doc == NULL) {
        xmlGenericError(xmlGenericErrorContext,
		"xmlValidateDocumentFinal: doc == NULL\n");
	return(0);
    }

    /*
     * Check all the NOTATION/NOTATIONS attributes
     */
    /*
     * Check all the ENTITY/ENTITIES attributes definition for validity
     */
    /*
     * Check all the IDREF/IDREFS attributes definition for validity
     */
    table = (xmlRefTablePtr) doc->refs;
    ctxt->doc = doc;
    ctxt->valid = 1;
    xmlHashScan(table, (xmlHashScanner) xmlValidateCheckRefCallback, ctxt);
    return(ctxt->valid);
}

/**
 * xmlValidateDtd:
 * @ctxt:  the validation context
 * @doc:  a document instance
 * @dtd:  a dtd instance
 *
 * Try to validate the document against the dtd instance
 *
 * basically it does check all the definitions in the DtD.
 *
 * returns 1 if valid or 0 otherwise
 */

int
xmlValidateDtd(xmlValidCtxtPtr ctxt, xmlDocPtr doc, xmlDtdPtr dtd) {
    int ret;
    xmlDtdPtr oldExt;
    xmlNodePtr root;

    if (dtd == NULL) return(0);
    if (doc == NULL) return(0);
    oldExt = doc->extSubset;
    doc->extSubset = dtd;
    ret = xmlValidateRoot(ctxt, doc);
    if (ret == 0) {
	doc->extSubset = oldExt;
	return(ret);
    }
    if (doc->ids != NULL) {
          xmlFreeIDTable(doc->ids);
          doc->ids = NULL;
    }
    if (doc->refs != NULL) {
          xmlFreeRefTable(doc->refs);
          doc->refs = NULL;
    }
    root = xmlDocGetRootElement(doc);
    ret = xmlValidateElement(ctxt, doc, root);
    ret &= xmlValidateDocumentFinal(ctxt, doc);
    doc->extSubset = oldExt;
    return(ret);
}

void
xmlValidateAttributeCallback(xmlAttributePtr cur, xmlValidCtxtPtr ctxt,
	                    const xmlChar *name) {
    if (cur == NULL)
	return;
    switch (cur->atype) {
	case XML_ATTRIBUTE_CDATA:
	case XML_ATTRIBUTE_ID:
	case XML_ATTRIBUTE_IDREF	:
	case XML_ATTRIBUTE_IDREFS:
	case XML_ATTRIBUTE_NMTOKEN:
	case XML_ATTRIBUTE_NMTOKENS:
	case XML_ATTRIBUTE_ENUMERATION:
	    break;
	case XML_ATTRIBUTE_ENTITY:
	case XML_ATTRIBUTE_ENTITIES:
	case XML_ATTRIBUTE_NOTATION:
	    if (cur->defaultValue != NULL) {
		ctxt->valid &= xmlValidateAttributeValue2(ctxt, ctxt->doc,
			    cur->name, cur->atype, cur->defaultValue);
	    }
	    if (cur->tree != NULL) {
		xmlEnumerationPtr tree = cur->tree;
		while (tree != NULL) {
		    ctxt->valid &= xmlValidateAttributeValue2(ctxt, ctxt->doc,
				    cur->name, cur->atype, tree->name);
		    tree = tree->next;
		}
	    }
    }
}

/**
 * xmlValidateDtdFinal:
 * @ctxt:  the validation context
 * @doc:  a document instance
 *
 * Does the final step for the dtds validation once all the
 * subsets have been parsed
 *
 * basically it does the following checks described by the XML Rec
 * - check that ENTITY and ENTITIES type attributes default or 
 *   possible values matches one of the defined entities.
 * - check that NOTATION type attributes default or 
 *   possible values matches one of the defined notations.
 *
 * returns 1 if valid or 0 otherwise
 */

int
xmlValidateDtdFinal(xmlValidCtxtPtr ctxt, xmlDocPtr doc) {
    int ret = 1;
    xmlDtdPtr dtd;
    xmlAttributeTablePtr table;

    if (doc == NULL) return(0);
    if ((doc->intSubset == NULL) && (doc->extSubset == NULL))
	return(0);
    ctxt->doc = doc;
    ctxt->valid = ret;
    dtd = doc->intSubset;
    if ((dtd != NULL) && (dtd->attributes != NULL)) {
	table = (xmlAttributeTablePtr) dtd->attributes;
	xmlHashScan(table, (xmlHashScanner) xmlValidateAttributeCallback, ctxt);
    }
    dtd = doc->extSubset;
    if ((dtd != NULL) && (dtd->attributes != NULL)) {
	table = (xmlAttributeTablePtr) dtd->attributes;
	xmlHashScan(table, (xmlHashScanner) xmlValidateAttributeCallback, ctxt);
    }
    return(ctxt->valid);
}

/**
 * xmlValidateDocument:
 * @ctxt:  the validation context
 * @doc:  a document instance
 *
 * Try to validate the document instance
 *
 * basically it does the all the checks described by the XML Rec
 * i.e. validates the internal and external subset (if present)
 * and validate the document tree.
 *
 * returns 1 if valid or 0 otherwise
 */

int
xmlValidateDocument(xmlValidCtxtPtr ctxt, xmlDocPtr doc) {
    int ret;
    xmlNodePtr root;

    if ((doc->intSubset == NULL) && (doc->extSubset == NULL))
	return(0);
    if ((doc->intSubset != NULL) && ((doc->intSubset->SystemID != NULL) ||
	(doc->intSubset->ExternalID != NULL)) && (doc->extSubset == NULL)) {
        doc->extSubset = xmlParseDTD(doc->intSubset->ExternalID,
		                     doc->intSubset->SystemID);
        if (doc->extSubset == NULL) {
	    if (doc->intSubset->SystemID != NULL) {
		VERROR(ctxt->userData, 
		       "Could not load the external subset \"%s\"\n",
		       doc->intSubset->SystemID);
	    } else {
		VERROR(ctxt->userData, 
		       "Could not load the external subset \"%s\"\n",
		       doc->intSubset->ExternalID);
	    }
	    return(0);
	}
    }

    if (doc->ids != NULL) {
          xmlFreeIDTable(doc->ids);
          doc->ids = NULL;
    }
    if (doc->refs != NULL) {
          xmlFreeRefTable(doc->refs);
          doc->refs = NULL;
    }
    ret = xmlValidateDtdFinal(ctxt, doc);
    if (!xmlValidateRoot(ctxt, doc)) return(0);

    root = xmlDocGetRootElement(doc);
    ret &= xmlValidateElement(ctxt, doc, root);
    ret &= xmlValidateDocumentFinal(ctxt, doc);
    return(ret);
}


/************************************************************************
 *									*
 *		Routines for dynamic validation editing			*
 *									*
 ************************************************************************/

/**
 * xmlValidGetPotentialChildren:
 * @ctree:  an element content tree
 * @list:  an array to store the list of child names
 * @len:  a pointer to the number of element in the list
 * @max:  the size of the array
 *
 * Build/extend a list of  potential children allowed by the content tree
 *
 * returns the number of element in the list, or -1 in case of error.
 */

int
xmlValidGetPotentialChildren(xmlElementContent *ctree, const xmlChar **list,
                             int *len, int max) {
    int i;

    if ((ctree == NULL) || (list == NULL) || (len == NULL))
        return(-1);
    if (*len >= max) return(*len);

    switch (ctree->type) {
	case XML_ELEMENT_CONTENT_PCDATA: 
	    for (i = 0; i < *len;i++)
		if (xmlStrEqual(BAD_CAST "#PCDATA", list[i])) return(*len);
	    list[(*len)++] = BAD_CAST "#PCDATA";
	    break;
	case XML_ELEMENT_CONTENT_ELEMENT: 
	    for (i = 0; i < *len;i++)
		if (xmlStrEqual(ctree->name, list[i])) return(*len);
	    list[(*len)++] = ctree->name;
	    break;
	case XML_ELEMENT_CONTENT_SEQ: 
	    xmlValidGetPotentialChildren(ctree->c1, list, len, max);
	    xmlValidGetPotentialChildren(ctree->c2, list, len, max);
	    break;
	case XML_ELEMENT_CONTENT_OR:
	    xmlValidGetPotentialChildren(ctree->c1, list, len, max);
	    xmlValidGetPotentialChildren(ctree->c2, list, len, max);
	    break;
   }
   
   return(*len);
}

/**
 * xmlValidGetValidElements:
 * @prev:  an element to insert after
 * @next:  an element to insert next
 * @list:  an array to store the list of child names
 * @max:  the size of the array
 *
 * This function returns the list of authorized children to insert
 * within an existing tree while respecting the validity constraints
 * forced by the Dtd. The insertion point is defined using @prev and
 * @next in the following ways:
 *  to insert before 'node': xmlValidGetValidElements(node->prev, node, ...
 *  to insert next 'node': xmlValidGetValidElements(node, node->next, ...
 *  to replace 'node': xmlValidGetValidElements(node->prev, node->next, ...
 *  to prepend a child to 'node': xmlValidGetValidElements(NULL, node->childs,
 *  to append a child to 'node': xmlValidGetValidElements(node->last, NULL, ...
 *
 * pointers to the element names are inserted at the beginning of the array
 * and do not need to be freed.
 *
 * returns the number of element in the list, or -1 in case of error. If
 *    the function returns the value @max the caller is invited to grow the
 *    receiving array and retry.
 */

int
xmlValidGetValidElements(xmlNode *prev, xmlNode *next, const xmlChar **list,
                         int max) {
    int nb_valid_elements = 0;
    const xmlChar *elements[256];
    int nb_elements = 0, i;
    
    xmlNode *ref_node;
    xmlNode *parent;
    xmlNode *test_node;
    
    xmlNode *prev_next;
    xmlNode *next_prev;
    xmlNode *parent_childs;
    xmlNode *parent_last;
    
    xmlElement *element_desc;

    if (prev == NULL && next == NULL)
        return(-1);

    if (list == NULL) return(-1);
    if (max <= 0) return(-1);

    nb_valid_elements = 0;
    ref_node = prev ? prev : next;
    parent = ref_node->parent;

    /*
     * Retrieves the parent element declaration
     */
    element_desc = xmlGetDtdElementDesc(parent->doc->intSubset,
                                         parent->name);
    if ((element_desc == NULL) && (parent->doc->extSubset != NULL))
        element_desc = xmlGetDtdElementDesc(parent->doc->extSubset,
                                             parent->name);
    if (element_desc == NULL) return(-1);
	
    /*
     * Do a backup of the current tree structure
     */
    prev_next = prev ? prev->next : NULL;
    next_prev = next ? next->prev : NULL;
    parent_childs = parent->children;
    parent_last = parent->last;

    /*
     * Creates a dummy node and insert it into the tree
     */    
    test_node = xmlNewNode (NULL, BAD_CAST "<!dummy?>");
    test_node->doc = ref_node->doc;
    test_node->parent = parent;
    test_node->prev = prev;
    test_node->next = next;
    
    if (prev) prev->next = test_node;
    else parent->children = test_node;
		
    if (next) next->prev = test_node;
    else parent->last = test_node;

    /*
     * Insert each potential child node and check if the parent is
     * still valid
     */
    nb_elements = xmlValidGetPotentialChildren(element_desc->content,
		       elements, &nb_elements, 256);
    
    for (i = 0;i < nb_elements;i++) {
	test_node->name = elements[i];
	if (xmlValidateOneElement(NULL, parent->doc, parent)) {
	    int j;

	    for (j = 0; j < nb_valid_elements;j++)
		if (xmlStrEqual(elements[i], list[j])) break;
	    list[nb_valid_elements++] = elements[i];
	    if (nb_valid_elements >= max) break;
	}
    }

    /*
     * Restore the tree structure
     */
    if (prev) prev->next = prev_next;
    if (next) next->prev = next_prev;
    parent->children = parent_childs;
    parent->last = parent_last;
    
    return(nb_valid_elements);
}