libxml2/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 "xmlmemory.h"
#include "valid.h"
#include "parser.h"
#include "parserInternals.h"

/* 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) return(0)

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

/****************************************************************
 *								*
 *	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) {
	        fprintf(stderr, "xmlNewElementContent : name == NULL !\n");
	    }
	    break;
        case XML_ELEMENT_CONTENT_PCDATA:
	case XML_ELEMENT_CONTENT_SEQ:
	case XML_ELEMENT_CONTENT_OR:
	    if (name != NULL) {
	        fprintf(stderr, "xmlNewElementContent : name != NULL !\n");
	    }
	    break;
	default:
	    fprintf(stderr, "xmlNewElementContent: unknown type %d\n", type);
	    exit(1);
    }
    ret = (xmlElementContentPtr) xmlMalloc(sizeof(xmlElementContent));
    if (ret == NULL) {
	fprintf(stderr, "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) {
        fprintf(stderr, "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;
    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:
	    fprintf(stderr, "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) {
    xmlElementTablePtr ret;

    ret = (xmlElementTablePtr) 
         xmlMalloc(sizeof(xmlElementTable));
    if (ret == NULL) {
        fprintf(stderr, "xmlCreateElementTable : xmlMalloc(%ld) failed\n",
	        (long)sizeof(xmlElementTable));
        return(NULL);
    }
    ret->max_elements = XML_MIN_ELEMENT_TABLE;
    ret->nb_elements = 0;
    ret->table = (xmlElementPtr *) 
         xmlMalloc(ret->max_elements * sizeof(xmlElementPtr));
    if (ret == NULL) {
        fprintf(stderr, "xmlCreateElementTable : xmlMalloc(%ld) failed\n",
	        ret->max_elements * (long)sizeof(xmlElement));
	xmlFree(ret);
        return(NULL);
    }
    return(ret);
}


/**
 * 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, cur;
    xmlElementTablePtr table;
    int i;

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

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

    /*
     * Validity Check:
     * Search the DTD for previous declarations of the ELEMENT
     */
    for (i = 0;i < table->nb_elements;i++) {
        cur = table->table[i];
	if (!xmlStrcmp(cur->name, name)) {
	    /*
	     * The element is already defined in this Dtd.
	     */
	    VERROR(ctxt->userData, "Redefinition of element %s\n", name);
	    return(NULL);
	}
    }

    /*
     * Grow the table, if needed.
     */
    if (table->nb_elements >= table->max_elements) {
        /*
	 * need more elements.
	 */
	table->max_elements *= 2;
	table->table = (xmlElementPtr *) 
	    xmlRealloc(table->table, table->max_elements * sizeof(xmlElementPtr));
	if (table->table == NULL) {
	    fprintf(stderr, "xmlAddElementDecl: out of memory\n");
	    return(NULL);
	}
    }
    ret = (xmlElementPtr) xmlMalloc(sizeof(xmlElement));
    if (ret == NULL) {
	fprintf(stderr, "xmlAddElementDecl: out of memory\n");
	return(NULL);
    }
    table->table[table->nb_elements] = ret;

    /*
     * fill the structure.
     */
    ret->type = type;
    ret->name = xmlStrdup(name);
    ret->content = xmlCopyElementContent(content);
    ret->attributes = xmlScanAttributeDecl(dtd, name);
    table->nb_elements++;

    return(ret);
}

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

/**
 * xmlFreeElementTable:
 * @table:  An element table
 *
 * Deallocate the memory used by an element hash table.
 */
void
xmlFreeElementTable(xmlElementTablePtr table) {
    int i;

    if (table == NULL) return;

    for (i = 0;i < table->nb_elements;i++) {
        xmlFreeElement(table->table[i]);
    }
    xmlFree(table->table);
    xmlFree(table);
}

/**
 * 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) {
    xmlElementTablePtr ret;
    xmlElementPtr cur, ent;
    int i;

    ret = (xmlElementTablePtr) xmlMalloc(sizeof(xmlElementTable));
    if (ret == NULL) {
        fprintf(stderr, "xmlCopyElementTable: out of memory !\n");
	return(NULL);
    }
    ret->table = (xmlElementPtr *) xmlMalloc(table->max_elements *
                                         sizeof(xmlElementPtr));
    if (ret->table == NULL) {
        fprintf(stderr, "xmlCopyElementTable: out of memory !\n");
	xmlFree(ret);
	return(NULL);
    }
    ret->max_elements = table->max_elements;
    ret->nb_elements = table->nb_elements;
    for (i = 0;i < ret->nb_elements;i++) {
	cur = (xmlElementPtr) xmlMalloc(sizeof(xmlElement));
	if (cur == NULL) {
	    fprintf(stderr, "xmlCopyElementTable: out of memory !\n");
	    xmlFree(ret);
	    xmlFree(ret->table);
	    return(NULL);
	}
	ret->table[i] = cur;
	ent = table->table[i];
	cur->type = ent->type;
	if (ent->name != NULL)
	    cur->name = xmlStrdup(ent->name);
	else
	    cur->name = NULL;
	cur->content = xmlCopyElementContent(ent->content);
	/* TODO : rebuild the attribute list on the copy */
	cur->attributes = NULL;
    }
    return(ret);
}

/**
 * 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) {
    int i;
    xmlElementPtr cur;

    if (table == NULL) return;

    for (i = 0;i < table->nb_elements;i++) {
        cur = table->table[i];
        switch (cur->type) {
	    case XML_ELEMENT_TYPE_EMPTY:
	        xmlBufferWriteChar(buf, "<!ELEMENT ");
		xmlBufferWriteCHAR(buf, cur->name);
		xmlBufferWriteChar(buf, " EMPTY>\n");
	        break;
	    case XML_ELEMENT_TYPE_ANY:
	        xmlBufferWriteChar(buf, "<!ELEMENT ");
		xmlBufferWriteCHAR(buf, cur->name);
		xmlBufferWriteChar(buf, " ANY>\n");
	        break;
	    case XML_ELEMENT_TYPE_MIXED:
	        xmlBufferWriteChar(buf, "<!ELEMENT ");
		xmlBufferWriteCHAR(buf, cur->name);
		xmlBufferWriteChar(buf, " ");
		xmlDumpElementContent(buf, cur->content, 1);
		xmlBufferWriteChar(buf, ">\n");
	        break;
	    case XML_ELEMENT_TYPE_ELEMENT:
	        xmlBufferWriteChar(buf, "<!ELEMENT ");
		xmlBufferWriteCHAR(buf, cur->name);
		xmlBufferWriteChar(buf, " ");
		xmlDumpElementContent(buf, cur->content, 1);
		xmlBufferWriteChar(buf, ">\n");
	        break;
	    default:
	        fprintf(stderr,
		    "xmlDumpElementTable: internal: unknown type %d\n",
		        cur->type);
	}
    }
}

/**
 * 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) {
        fprintf(stderr, "xmlCreateEnumeration : xmlMalloc(%ld) failed\n",
	        (long)sizeof(xmlEnumeration));
        return(NULL);
    }

    if (name != NULL)
        ret->name = xmlStrdup(name);
    else
        ret->name = NULL;
    ret->next = NULL;
    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) {
    xmlAttributeTablePtr ret;

    ret = (xmlAttributeTablePtr) 
         xmlMalloc(sizeof(xmlAttributeTable));
    if (ret == NULL) {
        fprintf(stderr, "xmlCreateAttributeTable : xmlMalloc(%ld) failed\n",
	        (long)sizeof(xmlAttributeTable));
        return(NULL);
    }
    ret->max_attributes = XML_MIN_ATTRIBUTE_TABLE;
    ret->nb_attributes = 0;
    ret->table = (xmlAttributePtr *) 
         xmlMalloc(ret->max_attributes * sizeof(xmlAttributePtr));
    if (ret == NULL) {
        fprintf(stderr, "xmlCreateAttributeTable : xmlMalloc(%ld) failed\n",
	        ret->max_attributes * (long)sizeof(xmlAttributePtr));
	xmlFree(ret);
        return(NULL);
    }
    return(ret);
}

/**
 * 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;
    int i;

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

    for (i = 0;i < table->nb_attributes;i++) {
        if (!xmlStrcmp(table->table[i]->elem, elem)) {
	    table->table[i]->next = ret;
	    ret = table->table[i];
	}
    }
    return(ret);
}

/**
 * xmlScanIDAttributeDecl:
 * @ctxt:  the validation context
 * @elem:  the element name
 *
 * Veryfy 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->type == 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->next;
    }
    return(ret);
}


/**
 * xmlAddAttributeDecl:
 * @ctxt:  the validation context
 * @dtd:  pointer to the DTD
 * @elem:  the element name
 * @name:  the attribute name
 * @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
 *
 * Returns NULL if not, othervise the entity
 */
xmlAttributePtr
xmlAddAttributeDecl(xmlValidCtxtPtr ctxt, xmlDtdPtr dtd, const xmlChar *elem,
                    const xmlChar *name, xmlAttributeType type, 
                    xmlAttributeDefault def, const xmlChar *defaultValue,
                    xmlEnumerationPtr tree) {
    xmlAttributePtr ret, cur;
    xmlAttributeTablePtr table;
    xmlElementPtr elemDef;
    xmlChar *rname;
    xmlChar *ns;
    int i;

    if (dtd == NULL) {
        fprintf(stderr, "xmlAddAttributeDecl: dtd == NULL\n");
	return(NULL);
    }
    if (name == NULL) {
        fprintf(stderr, "xmlAddAttributeDecl: name == NULL\n");
	return(NULL);
    }
    if (elem == NULL) {
        fprintf(stderr, "xmlAddAttributeDecl: elem == NULL\n");
	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:
	    fprintf(stderr, "xmlAddAttributeDecl: unknown type %d\n", type);
	    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 = dtd->attributes;
    if (table == NULL) 
        table = dtd->attributes = xmlCreateAttributeTable();
    if (table == NULL) {
	fprintf(stderr, "xmlAddAttributeDecl: Table creation failed!\n");
        return(NULL);
    }

    /*
     * Split the full name into a namespace prefix and the tag name
     */
    rname = xmlSplitQName(name, &ns);

    /*
     * Validity Check:
     * Search the DTD for previous declarations of the ATTLIST
     */
    for (i = 0;i < table->nb_attributes;i++) {
        cur = table->table[i];
	if ((ns != NULL) && (cur->prefix == NULL)) continue;
	if ((ns == NULL) && (cur->prefix != NULL)) continue;
	if ((!xmlStrcmp(cur->name, rname)) && (!xmlStrcmp(cur->elem, elem)) &&
	    ((ns == NULL) || (!xmlStrcmp(cur->prefix, ns)))) {
	    /*
	     * The attribute is already defined in this Dtd.
	     */
	    VERROR(ctxt->userData, "Attribute %s on %s: already defined\n",
		   elem, name);
	}
    }

    /*
     * Grow the table, if needed.
     */
    if (table->nb_attributes >= table->max_attributes) {
        /*
	 * need more attributes.
	 */
	table->max_attributes *= 2;
	table->table = (xmlAttributePtr *) 
	    xmlRealloc(table->table, table->max_attributes * 
	            sizeof(xmlAttributePtr));
	if (table->table == NULL) {
	    fprintf(stderr, "xmlAddAttributeDecl: out of memory\n");
	    return(NULL);
	}
    }
    ret = (xmlAttributePtr) xmlMalloc(sizeof(xmlAttribute));
    if (ret == NULL) {
	fprintf(stderr, "xmlAddAttributeDecl: out of memory\n");
	return(NULL);
    }
    table->table[table->nb_attributes] = ret;

    /*
     * fill the structure.
     */
    ret->type = type;
    ret->name = rname;
    ret->prefix = ns;
    ret->elem = xmlStrdup(elem);
    ret->def = def;
    ret->tree = tree;
    if (defaultValue != NULL)
	ret->defaultValue = xmlStrdup(defaultValue);
    else
        ret->defaultValue = NULL;
    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->next = elemDef->attributes;
        elemDef->attributes = ret;
    }
    table->nb_attributes++;

    return(ret);
}

/**
 * xmlFreeAttribute:
 * @elem:  An attribute
 *
 * Deallocate the memory used by an attribute definition
 */
void
xmlFreeAttribute(xmlAttributePtr attr) {
    if (attr == NULL) return;
    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);
}

/**
 * xmlFreeAttributeTable:
 * @table:  An attribute table
 *
 * Deallocate the memory used by an entities hash table.
 */
void
xmlFreeAttributeTable(xmlAttributeTablePtr table) {
    int i;

    if (table == NULL) return;

    for (i = 0;i < table->nb_attributes;i++) {
        xmlFreeAttribute(table->table[i]);
    }
    xmlFree(table->table);
    xmlFree(table);
}

/**
 * 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) {
    xmlAttributeTablePtr ret;
    xmlAttributePtr cur, attr;
    int i;

    ret = (xmlAttributeTablePtr) xmlMalloc(sizeof(xmlAttributeTable));
    if (ret == NULL) {
        fprintf(stderr, "xmlCopyAttributeTable: out of memory !\n");
	return(NULL);
    }
    ret->table = (xmlAttributePtr *) xmlMalloc(table->max_attributes *
                                          sizeof(xmlAttributePtr));
    if (ret->table == NULL) {
        fprintf(stderr, "xmlCopyAttributeTable: out of memory !\n");
	xmlFree(ret);
	return(NULL);
    }
    ret->max_attributes = table->max_attributes;
    ret->nb_attributes = table->nb_attributes;
    for (i = 0;i < ret->nb_attributes;i++) {
	attr = table->table[i];
	cur = (xmlAttributePtr) xmlMalloc(sizeof(xmlAttribute));
	if (cur == NULL) {
	    fprintf(stderr, "xmlCopyAttributeTable: out of memory !\n");
	    xmlFree(ret);
	    xmlFree(ret->table);
	    return(NULL);
	}
	ret->table[i] = cur;
	cur->type = attr->type;
	cur->def = attr->def;
	cur->tree = xmlCopyEnumeration(attr->tree);
	if (attr->elem != NULL)
	    cur->elem = xmlStrdup(attr->elem);
	else
	    cur->elem = NULL;
	if (attr->name != NULL)
	    cur->name = xmlStrdup(attr->name);
	else
	    cur->name = NULL;
	if (attr->defaultValue != NULL)
	    cur->defaultValue = xmlStrdup(attr->defaultValue);
	else
	    cur->defaultValue = NULL;
	/* NEED to rebuild the next chain !!!!!! */
    }
    return(ret);
}

/**
 * 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) {
    int i;
    xmlAttributePtr cur;

    if (table == NULL) return;

    for (i = 0;i < table->nb_attributes;i++) {
        cur = table->table[i];
	xmlBufferWriteChar(buf, "<!ATTLIST ");
	xmlBufferWriteCHAR(buf, cur->elem);
	xmlBufferWriteChar(buf, " ");
	xmlBufferWriteCHAR(buf, cur->name);
        switch (cur->type) {
            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, cur->tree);
                break;
            case XML_ATTRIBUTE_NOTATION:
                xmlBufferWriteChar(buf, " NOTATION (");
		xmlDumpEnumeration(buf, cur->tree);
                break;
	    default:
	        fprintf(stderr,
		    "xmlDumpAttributeTable: internal: unknown type %d\n",
		        cur->type);
	}
        switch (cur->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:
	        fprintf(stderr,
		    "xmlDumpAttributeTable: internal: unknown default %d\n",
		        cur->def);
        }
	if (cur->defaultValue != NULL) {
	    xmlBufferWriteChar(buf, " ");
	    xmlBufferWriteQuotedString(buf, cur->defaultValue);
	}
        xmlBufferWriteChar(buf, ">\n");
    }
}

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

    ret = (xmlNotationTablePtr) 
         xmlMalloc(sizeof(xmlNotationTable));
    if (ret == NULL) {
        fprintf(stderr, "xmlCreateNotationTable : xmlMalloc(%ld) failed\n",
	        (long)sizeof(xmlNotationTable));
        return(NULL);
    }
    ret->max_notations = XML_MIN_NOTATION_TABLE;
    ret->nb_notations = 0;
    ret->table = (xmlNotationPtr *) 
         xmlMalloc(ret->max_notations * sizeof(xmlNotationPtr));
    if (ret == NULL) {
        fprintf(stderr, "xmlCreateNotationTable : xmlMalloc(%ld) failed\n",
	        ret->max_notations * (long)sizeof(xmlNotation));
	xmlFree(ret);
        return(NULL);
    }
    return(ret);
}


/**
 * 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, cur;
    xmlNotationTablePtr table;
    int i;

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

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

    /*
     * Validity Check:
     * Search the DTD for previous declarations of the ATTLIST
     */
    for (i = 0;i < table->nb_notations;i++) {
        cur = table->table[i];
	if (!xmlStrcmp(cur->name, name)) {
	    /*
	     * The notation is already defined in this Dtd.
	     */
	    fprintf(stderr,
		    "xmlAddNotationDecl: %s already defined\n", name);
	}
    }

    /*
     * Grow the table, if needed.
     */
    if (table->nb_notations >= table->max_notations) {
        /*
	 * need more notations.
	 */
	table->max_notations *= 2;
	table->table = (xmlNotationPtr *) 
	    xmlRealloc(table->table, table->max_notations *
	            sizeof(xmlNotationPtr));
	if (table->table == NULL) {
	    fprintf(stderr, "xmlAddNotationDecl: out of memory\n");
	    return(NULL);
	}
    }
    ret = (xmlNotationPtr) xmlMalloc(sizeof(xmlNotation));
    if (ret == NULL) {
	fprintf(stderr, "xmlAddNotationDecl: out of memory\n");
	return(NULL);
    }
    table->table[table->nb_notations] = ret;

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

    return(ret);
}

/**
 * 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);
}

/**
 * xmlFreeNotationTable:
 * @table:  An notation table
 *
 * Deallocate the memory used by an entities hash table.
 */
void
xmlFreeNotationTable(xmlNotationTablePtr table) {
    int i;

    if (table == NULL) return;

    for (i = 0;i < table->nb_notations;i++) {
        xmlFreeNotation(table->table[i]);
    }
    xmlFree(table->table);
    xmlFree(table);
}

/**
 * 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) {
    xmlNotationTablePtr ret;
    xmlNotationPtr cur, nota;
    int i;

    ret = (xmlNotationTablePtr) xmlMalloc(sizeof(xmlNotationTable));
    if (ret == NULL) {
        fprintf(stderr, "xmlCopyNotationTable: out of memory !\n");
	return(NULL);
    }
    ret->table = (xmlNotationPtr *) xmlMalloc(table->max_notations *
                                         sizeof(xmlNotationPtr));
    if (ret->table == NULL) {
        fprintf(stderr, "xmlCopyNotationTable: out of memory !\n");
	xmlFree(ret);
	return(NULL);
    }
    ret->max_notations = table->max_notations;
    ret->nb_notations = table->nb_notations;
    for (i = 0;i < ret->nb_notations;i++) {
	cur = (xmlNotationPtr) xmlMalloc(sizeof(xmlNotation));
	if (cur == NULL) {
	    fprintf(stderr, "xmlCopyNotationTable: out of memory !\n");
	    xmlFree(ret);
	    xmlFree(ret->table);
	    return(NULL);
	}
	ret->table[i] = cur;
	nota = table->table[i];
	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(ret);
}

/**
 * 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) {
    int i;
    xmlNotationPtr cur;

    if (table == NULL) return;

    for (i = 0;i < table->nb_notations;i++) {
        cur = table->table[i];
	xmlBufferWriteChar(buf, "<!NOTATION ");
	xmlBufferWriteCHAR(buf, cur->name);
	if (cur->PublicID != NULL) {
	    xmlBufferWriteChar(buf, " PUBLIC ");
	    xmlBufferWriteQuotedString(buf, cur->PublicID);
	    if (cur->SystemID != NULL) {
		xmlBufferWriteChar(buf, " ");
		xmlBufferWriteCHAR(buf, cur->SystemID);
	    }
	} else {
	    xmlBufferWriteChar(buf, " SYSTEM ");
	    xmlBufferWriteCHAR(buf, cur->SystemID);
	}
        xmlBufferWriteChar(buf, " >\n");
    }
}

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

    ret = (xmlIDTablePtr) 
         xmlMalloc(sizeof(xmlIDTable));
    if (ret == NULL) {
        fprintf(stderr, "xmlCreateIDTable : xmlMalloc(%ld) failed\n",
	        (long)sizeof(xmlIDTable));
        return(NULL);
    }
    ret->max_ids = XML_MIN_NOTATION_TABLE;
    ret->nb_ids = 0;
    ret->table = (xmlIDPtr *) 
         xmlMalloc(ret->max_ids * sizeof(xmlIDPtr));
    if (ret == NULL) {
        fprintf(stderr, "xmlCreateIDTable : xmlMalloc(%ld) failed\n",
	        ret->max_ids * (long)sizeof(xmlID));
	xmlFree(ret);
        return(NULL);
    }
    return(ret);
}


/**
 * 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, cur;
    xmlIDTablePtr table;
    int i;

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

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

    /*
     * Validity Check:
     * Search the DTD for previous declarations of the ATTLIST
     */
    for (i = 0;i < table->nb_ids;i++) {
        cur = table->table[i];
	if (!xmlStrcmp(cur->value, value)) {
	    /*
	     * The id is already defined in this Dtd.
	     */
	    VERROR(ctxt->userData, "ID %s already defined\n", value);
	    return(NULL);
	}
    }

    /*
     * Grow the table, if needed.
     */
    if (table->nb_ids >= table->max_ids) {
        /*
	 * need more ids.
	 */
	table->max_ids *= 2;
	table->table = (xmlIDPtr *) 
	    xmlRealloc(table->table, table->max_ids *
	            sizeof(xmlIDPtr));
	if (table->table == NULL) {
	    fprintf(stderr, "xmlAddID: out of memory\n");
	    return(NULL);
	}
    }
    ret = (xmlIDPtr) xmlMalloc(sizeof(xmlID));
    if (ret == NULL) {
	fprintf(stderr, "xmlAddID: out of memory\n");
	return(NULL);
    }
    table->table[table->nb_ids] = ret;

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

    return(ret);
}

/**
 * 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);
}

/**
 * xmlFreeIDTable:
 * @table:  An id table
 *
 * Deallocate the memory used by an ID hash table.
 */
void
xmlFreeIDTable(xmlIDTablePtr table) {
    int i;

    if (table == NULL) return;

    for (i = 0;i < table->nb_ids;i++) {
        xmlFreeID(table->table[i]);
    }
    xmlFree(table->table);
    xmlFree(table);
}

/**
 * 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->intSubset == NULL) && (doc->extSubset == NULL)) {
        if (((attr->name[0] == 'I') || (attr->name[0] == 'i')) &&
            ((attr->name[1] == 'D') || (attr->name[1] == 'd')) &&
	    (attr->name[2] == 0)) return(1);
    } 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->type == XML_ATTRIBUTE_ID))
	    return(1);
    }
    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) {
    xmlIDPtr cur;
    xmlIDTablePtr table;
    int i;

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

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

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

    /*
     * Search the ID list.
     */
    for (i = 0;i < table->nb_ids;i++) {
        cur = table->table[i];
	if (!xmlStrcmp(cur->value, ID)) {
	    return(cur->attr);
	}
    }
    return(NULL);
}

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

    ret = (xmlRefTablePtr) 
         xmlMalloc(sizeof(xmlRefTable));
    if (ret == NULL) {
        fprintf(stderr, "xmlCreateRefTable : xmlMalloc(%ld) failed\n",
	        (long)sizeof(xmlRefTable));
        return(NULL);
    }
    ret->max_refs = XML_MIN_NOTATION_TABLE;
    ret->nb_refs = 0;
    ret->table = (xmlRefPtr *) 
         xmlMalloc(ret->max_refs * sizeof(xmlRefPtr));
    if (ret == NULL) {
        fprintf(stderr, "xmlCreateRefTable : xmlMalloc(%ld) failed\n",
	        ret->max_refs * (long)sizeof(xmlRef));
	xmlFree(ret);
        return(NULL);
    }
    return(ret);
}


/**
 * 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) {
        fprintf(stderr, "xmlAddRefDecl: doc == NULL\n");
	return(NULL);
    }
    if (value == NULL) {
        fprintf(stderr, "xmlAddRefDecl: value == NULL\n");
	return(NULL);
    }
    if (attr == NULL) {
        fprintf(stderr, "xmlAddRefDecl: attr == NULL\n");
	return(NULL);
    }

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

    /*
     * Grow the table, if needed.
     */
    if (table->nb_refs >= table->max_refs) {
        /*
	 * need more refs.
	 */
	table->max_refs *= 2;
	table->table = (xmlRefPtr *) 
	    xmlRealloc(table->table, table->max_refs *
	            sizeof(xmlRefPtr));
	if (table->table == NULL) {
	    fprintf(stderr, "xmlAddRef: out of memory\n");
	    return(NULL);
	}
    }
    ret = (xmlRefPtr) xmlMalloc(sizeof(xmlRef));
    if (ret == NULL) {
	fprintf(stderr, "xmlAddRef: out of memory\n");
	return(NULL);
    }
    table->table[table->nb_refs] = ret;

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

    return(ret);
}

/**
 * xmlFreeRef:
 * @not:  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);
}

/**
 * xmlFreeRefTable:
 * @table:  An ref table
 *
 * Deallocate the memory used by an Ref hash table.
 */
void
xmlFreeRefTable(xmlRefTablePtr table) {
    int i;

    if (table == NULL) return;

    for (i = 0;i < table->nb_refs;i++) {
        xmlFreeRef(table->table[i]);
    }
    xmlFree(table->table);
    xmlFree(table);
}

/**
 * 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);
	/*******************
        if (((attr->name[0] == 'I') || (attr->name[0] == 'i')) &&
            ((attr->name[1] == 'D') || (attr->name[1] == 'd')) &&
	    (attr->name[2] == 0)) return(1);
	 *******************/
    } 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->type == XML_ATTRIBUTE_IDREF))
	    return(1);
    }
    return(0);
}

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

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

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

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

    /*
     * Search the Ref list.
     */
    for (i = 0;i < table->nb_refs;i++) {
        cur = table->table[i];
	if (!xmlStrcmp(cur->value, Ref)) {
	    return(cur->attr);
	}
    }
    return(NULL);
}

/************************************************************************
 *									*
 *		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;
    int i;

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

    for (i = 0;i < table->nb_elements;i++) {
        cur = table->table[i];
	if (!xmlStrcmp(cur->name, name))
	    return(cur);
    }
    return(NULL);
}

/**
 * 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;
    int i;

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

    for (i = 0;i < table->nb_attributes;i++) {
        cur = table->table[i];
	if ((!xmlStrcmp(cur->name, name)) &&
	    (!xmlStrcmp(cur->elem, elem)))
	    return(cur);
    }
    return(NULL);
}

/**
 * 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;
    xmlNotationPtr cur;
    int i;

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

    for (i = 0;i < table->nb_notations;i++) {
        cur = table->table[i];
	if (!xmlStrcmp(cur->name, name))
	    return(cur);
    }
    return(NULL);
}

/**
 * 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->type) {
	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;
    
    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 (!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);
}

/**
 * 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->type, 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->type == 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->type == XML_ATTRIBUTE_ID) && (doc->extSubset != NULL)) {
        int nbId = 0;

	/* the trick is taht we parse DtD as their own internal subset */
        xmlElementPtr elem = xmlGetDtdElementDesc(doc->extSubset,
	                                          attr->elem);
	if (elem != NULL) {
	    nbId = xmlScanIDAttributeDecl(NULL, elem);
	}
	if (nbId >= 1)
	    VERROR(ctxt->userData, 
	   "Element %s has ID attribute defined in the external subset : %s\n",
		   attr->elem, attr->name);
    }

    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->type == 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 (!xmlStrcmp(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 (!xmlStrcmp(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;
    int val;
    int ret = 1;

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


    /* 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);
    }
    val = xmlValidateAttributeValue(attrDecl->type, 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: ID uniqueness */
    if (attrDecl->type == XML_ATTRIBUTE_ID) {
        xmlAddID(ctxt, doc, value, attr);
    }

    if (attrDecl->type == XML_ATTRIBUTE_IDREF) {
        xmlAddRef(ctxt, doc, value, attr);
    }

    /* Validity Constraint: Notation Attributes */
    if (attrDecl->type == 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 (!xmlStrcmp(tree->name, value)) break;
	    tree = tree->next;
	}
	if (tree == NULL) {
	    VERROR(ctxt->userData, 
   "Value \"%s\" for attribute %s on %s is among the enumerated notations\n",
		   value, attr->name, elem->name);
	    ret = 0;
	}
    }

    /* Validity Constraint: Enumeration */
    if (attrDecl->type == XML_ATTRIBUTE_ENUMERATION) {
        xmlEnumerationPtr tree = attrDecl->tree;
	while (tree != NULL) {
	    if (!xmlStrcmp(tree->name, value)) break;
	    tree = tree->next;
	}
	if (tree == NULL) {
	    VERROR(ctxt->userData, 
       "Value \"%s\" for attribute %s on %s is among the enumerated set\n",
		   value, attr->name, elem->name);
	    ret = 0;
	}
    }

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

    /********
    elemDecl = xmlGetDtdElementDesc(doc->intSubset, elem->name);
    if ((elemDecl == NULL) && (doc->extSubset != NULL))
	elemDecl = xmlGetDtdElementDesc(doc->extSubset, elem->name);
    if (elemDecl == NULL) {
	return(0);
    }
     ********/
    return(ret);
}

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);
    while (*child != NULL) {
        if ((*child)->type == XML_PI_NODE) {
	    *child = (*child)->next;
	    continue;
	}
        if ((*child)->type == XML_COMMENT_NODE) {
	    *child = (*child)->next;
	    continue;
	}
	else if ((*child)->type != XML_ELEMENT_NODE) {
	    return(-1);
	}
	break;
    }
    switch (cont->type) {
	case XML_ELEMENT_CONTENT_PCDATA:
	    /* Internal error !!! */
	    fprintf(stderr, "Internal: MIXED struct bad\n");
	    return(-1);
	case XML_ELEMENT_CONTENT_ELEMENT:
	    if (*child == NULL) return(0);
	    ret = (!xmlStrcmp((*child)->name, cont->name));
	    if (ret == 1)
	        *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 = 1;

    if (cont == NULL) return(-1);
    while (*child != NULL) {
        if ((*child)->type == XML_PI_NODE) {
	    *child = (*child)->next;
	    continue;
	}
        if ((*child)->type == XML_COMMENT_NODE) {
	    *child = (*child)->next;
	    continue;
	}
	else if ((*child)->type != XML_ELEMENT_NODE) {
	    return(-1);
	}
	break;
    }
    cur = *child;
    ret = xmlValidateElementTypeExpr(ctxt, child, cont);
    if (ret == -1) return(-1);
    switch (cont->ocur) {
	case XML_ELEMENT_CONTENT_ONCE:
	    if (ret == 1) {
		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);
	    }
	    do {
		cur = *child;
		ret = xmlValidateElementTypeExpr(ctxt, child, cont);
	    } while (ret == 1);
	    if (ret == -1) return(-1);
	    *child = cur;
	    break;
    }
    while (*child != NULL) {
        if ((*child)->type == XML_PI_NODE) {
	    *child = (*child)->next;
	    continue;
	}
        if ((*child)->type == XML_COMMENT_NODE) {
	    *child = (*child)->next;
	    continue;
	}
	else if ((*child)->type != XML_ELEMENT_NODE) {
	    return(-1);
	}
	break;
    }
    return(1);
}

/**
 * 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->childs;
    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:
            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:
	    case XML_HTML_DOCUMENT_NODE:
            case XML_DOCUMENT_TYPE_NODE:
            case XML_DOCUMENT_FRAG_NODE:
            case XML_NOTATION_NODE:
	         strcat(buf, "???");
		 if (cur->next != NULL)
		     strcat(buf, " ");
		 break;
            case XML_ENTITY_NODE:
            case XML_PI_NODE:
            case XML_COMMENT_NODE:
		 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;
    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->childs != 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->ns != 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_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);

    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->type) {
        case XML_ELEMENT_TYPE_EMPTY:
	    if (elem->childs != 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->childs;
	    while (child != NULL) {
	        if (child->type == XML_ELEMENT_NODE) {
		    name = child->name;
		    cont = elemDecl->content;
		    while (cont != NULL) {
		        if (cont->type == XML_ELEMENT_CONTENT_ELEMENT) {
			    if (!xmlStrcmp(cont->name, name)) break;
			} else if ((cont->type == XML_ELEMENT_CONTENT_OR) &&
			   (cont->c1 != NULL) &&
			   (cont->c1->type == XML_ELEMENT_CONTENT_ELEMENT)) {
			    if (!xmlStrcmp(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 !!! */
			    fprintf(stderr, "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 = child->next;
	    }
	    break;
        case XML_ELEMENT_TYPE_ELEMENT:
	    child = elem->childs;
	    cont = elemDecl->content;
	    ret = xmlValidateElementTypeElement(ctxt, &child, cont);
	    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 (!xmlStrcmp(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 (xmlStrcmp(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);
	        } else {
		    VERROR(ctxt->userData,
		       "Element %s doesn't carry attribute %s:%s\n",
			   elem->name, attr->prefix,attr->name);
		}
	    } 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->next;
    }
    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);

    if ((doc->intSubset == NULL) ||
	(doc->intSubset->name == NULL)) {
	VERROR(ctxt->userData, "Not valid: no DtD found\n");
        return(0);
    }
    root = xmlDocGetRootElement(doc);
    if ((root == NULL) || (root->name == NULL)) {
	VERROR(ctxt->userData, "Not valid: no root element\n");
        return(0);
    }
    if (xmlStrcmp(doc->intSubset->name, root->name)) {
	VERROR(ctxt->userData,
	       "Not valid: root and DtD name do not match '%s' and '%s'\n",
	       root->name, doc->intSubset->name);
	return(0);
    }
    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);
    CHECK_DTD;

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

    return(ret);
}

/**
 * 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) {
    int ret = 1, i;
    xmlRefTablePtr table;
    xmlAttrPtr id;

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

    /*
     * Get the refs table
     */
    table = doc->refs;
    if (table != NULL) {
        for (i = 0; i < table->nb_refs; i++) {
	    id = xmlGetID(doc, table->table[i]->value);
	    if (id == NULL) {
		VERROR(ctxt->userData, 
		       "IDREF attribute %s reference an unknown ID '%s'\n",
		       table->table[i]->attr->name, table->table[i]->value);
	        ret = 0;
	    }
	}
    }
    return(ret);
}

/**
 * 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);
    }
    root = xmlDocGetRootElement(doc);
    ret = xmlValidateElement(ctxt, doc, root);
    ret &= xmlValidateDocumentFinal(ctxt, doc);
    doc->extSubset = oldExt;
    return(ret);
}

/**
 * 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 (!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 (!xmlStrcmp(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 (!xmlStrcmp(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->childs;
    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->childs = 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 (!xmlStrcmp(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->childs = parent_childs;
    parent->last = parent_last;
    
    return(nb_valid_elements);
}