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#include "uwsgi.h"
extern struct uwsgi_server uwsgi;
// Bernstein classic hash (this is not static as it is used by other areas)
uint32_t djb33x_hash(char *key, uint64_t keylen) {
register uint32_t hash = 5381;
uint64_t i;
for (i = 0; i < keylen; i++) {
hash = ((hash << 5) + hash) ^ key[i];
}
return hash;
}
// Murmur2 hash Copyright (C) Austin Appleby
// adapted from nginx
static uint32_t murmur2_hash(char *key, uint64_t keylen) {
uint32_t h, k;
uint8_t *ukey = (uint8_t *) key;
h = 0 ^ keylen;
while (keylen >= 4) {
k = ukey[0];
k |= ukey[1] << 8;
k |= ukey[2] << 16;
k |= ukey[3] << 24;
k *= 0x5bd1e995;
k ^= k >> 24;
k *= 0x5bd1e995;
h *= 0x5bd1e995;
h ^= k;
ukey += 4;
keylen -= 4;
}
switch (keylen) {
case 3:
h ^= key[2] << 16;
/* fallthrough */
case 2:
h ^= key[1] << 8;
/* fallthrough */
case 1:
h ^= key[0];
h *= 0x5bd1e995;
}
h ^= h >> 13;
h *= 0x5bd1e995;
h ^= h >> 15;
return h;
}
static uint32_t random_hash(char *key, uint64_t keylen) {
return (uint32_t) rand();
}
/*
not atomic, avoid its use in multithreaded modes
*/
static uint32_t rr_hash(char *key, uint64_t keylen) {
static uint32_t rr = 0;
uint32_t max_value = uwsgi_str_num(key, keylen);
uint32_t ret = rr;
rr++;
if (rr > max_value) {
rr = 0;
}
return ret;
}
struct uwsgi_hash_algo *uwsgi_hash_algo_get(char *name) {
struct uwsgi_hash_algo *uha = uwsgi.hash_algos;
while(uha) {
if (!strcmp(name, uha->name)) {
return uha;
}
uha = uha->next;
}
return NULL;
}
void uwsgi_hash_algo_register(char *name, uint32_t (*func)(char *, uint64_t)) {
struct uwsgi_hash_algo *old_uha = NULL, *uha = uwsgi.hash_algos;
while(uha) {
if (!strcmp(uha->name, name)) return;
old_uha = uha;
uha = uha->next;
}
uha = uwsgi_calloc(sizeof(struct uwsgi_hash_algo));
uha->name = name;
uha->func = func;
if (old_uha) {
old_uha->next = uha;
}
else {
uwsgi.hash_algos = uha;
}
}
void uwsgi_hash_algo_register_all() {
uwsgi_hash_algo_register("djb33x", djb33x_hash);
uwsgi_hash_algo_register("murmur2", murmur2_hash);
uwsgi_hash_algo_register("random", random_hash);
uwsgi_hash_algo_register("rand", random_hash);
uwsgi_hash_algo_register("rr", rr_hash);
}
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