xmlStrstr(const xmlChar *str, const xmlChar *val) {
    int n;

    if (str == NULL) return(NULL);
    if (val == NULL) return(NULL);
    n = xmlStrlen(val);

    if (n == 0) return(str);
    while (*str != 0) { /* non input consuming */
        if (*str == *val) {
            if (!xmlStrncmp(str, val, n)) return((const xmlChar *) str);
        }
        str++;
    }
    return(NULL);
}
xmlStrstr(const xmlChar *str, const xmlChar *val) {
    int n;

    if (str == NULL) return(NULL);
    if (val == NULL) return(NULL);
    n = xmlStrlen(val);

    if (n == 0) return(str);
    while (*str != 0) {  
        if (*str == *val) {
            if (!xmlStrncmp(str, val, n)) return((const xmlChar *) str);
        }
        str++;
    }
    return(NULL);
}