/*
 * fast path concatation
 */
char *path_cat(const char *s1, char *s2)
{
    size_t slen[2] = {
        strlen(s1),
        strlen(s2)
    };

    char *result = malloc((slen[0] + slen[1] + 1) * sizeof(char));

    memcpy(result, s1, strlen(s1));

    int i,j;
    for (i = slen[0], j = 0; ((i <(slen[0] + slen[1])) && (j < slen[1])); i++, j++)
        result[i] = s2[j];

    return (!(result[slen[0]+slen[1]] = '\0')) ? result : NULL
}