/**
 * xmlListLowerSearch:
 * @l:  a list
 * @data:  a data
 *
 * Search data in the ordered list walking from the beginning
 *
 * Returns the link containing the data or NULL
 */
static xmlLinkPtr 
xmlListLowerSearch(xmlListPtr l, void *data) 
{
    xmlLinkPtr lk;

    for(lk = l->sentinel->next;lk != l->sentinel && l->linkCompare(lk->data, data) <0 ;lk = lk->next);
    return lk;    
}

/**
 * xmlListHigherSearch:
 * @l:  a list
 * @data:  a data
 *
 * Search data in the ordered list walking backward from the end
 *
 * Returns the link containing the data or NULL
 */
static xmlLinkPtr 
xmlListHigherSearch(xmlListPtr l, void *data) 
{
    xmlLinkPtr lk;

    for(lk = l->sentinel->prev;lk != l->sentinel && l->linkCompare(lk->data, data) >0 ;lk = lk->prev);
    return lk;    
}

/**
 * xmlLinkDeallocator:
 * @l:  a list
 * @lk:  a link
 *
 * Unlink and deallocate @lk from list @l
 */
static void
xmlLinkDeallocator(xmlListPtr l, xmlLinkPtr lk)
{
    (lk->prev)->next = lk->next;
    (lk->next)->prev = lk->prev;
    if (l->linkDeallocator)
        l->linkDeallocator(lk);
    xmlFree(lk);
}

/**
 * xmlListLinkReverseSearch:
 * @param l a list
 * @param data a data
 *
 * Search data in the list processing backward
 *
 * Returns the link containing the data or NULL
 */
static xmlLinkPtr
xmlListLinkReverseSearch(xmlListPtr list, void *data)
{
    xmlLinkPtr lk;
    lk = xmlListHigherSearch(list, data);
    if (lk == list->sentinel)
        return NULL;
    else {
        if (list->linkCompare(lk->data, data) ==0)
            return lk;
        return NULL;
    }
}

/**
 * xmlListSearch:
 * @l:  a list
 * @data:  a data
 *
 * Search data in the list
 *
 * Returns the link containing the data or NULL
 */
static xmlLinkPtr 
xmlListLinkSearch(xmlListPtr l, void *data) 
{
    xmlLinkPtr lk;
    lk = xmlListLowerSearch(l, data);
    if (lk == l->sentinel)
        return NULL;
    else {
        if (l->linkCompare(lk->data, data) ==0)
            return lk;
        return NULL;
    }
}