string hash from cairo

cairo_hash_string.c

#define _CAIRO_HASH_INIT_VALUE 5381

unsigned long _cairo_hash_string (const char *c)
{
    /* This is the djb2 hash. */
    unsigned long hash = _CAIRO_HASH_INIT_VALUE;
    while (c && *c)
	hash = ((hash << 5) + hash) + *c++;
    return hash;
}