uint32_t vb__hash_ketama(const char *key, size_t key_length)
{
unsigned char digest[16];
vb__hash_md5(key, key_length, digest);
return (uint32_t) ( (digest[3] << 24)
|(digest[2] << 16)
|(digest[1] << 8)
| digest[0]);
}
static int
update_ketama(lcbvb_CONFIG *cfg)
{
char host[MAX_AUTHORITY_SIZE+10] = "";
int nhost;
unsigned pp, hh, ss, nn;
unsigned char digest[16];
lcbvb_CONTINUUM *new_continuum, *old_continuum;
qsort(cfg->servers, cfg->ndatasrv, sizeof(*cfg->servers), server_cmp);
new_continuum = calloc(160 * cfg->ndatasrv, sizeof(*new_continuum));
/* 40 hashes, 4 numbers per hash = 160 points per server */
for (ss = 0, pp = 0; ss < cfg->ndatasrv; ++ss) {
/* we can add more points to server which have more memory */
for (hh = 0; hh < 40; ++hh) {
lcbvb_SERVER *srv = cfg->servers + ss;
nhost = snprintf(host, MAX_AUTHORITY_SIZE+10, "%s-%u", srv->authority, hh);
vb__hash_md5(host, nhost, digest);
for (nn = 0; nn < 4; ++nn, ++pp) {
new_continuum[pp].index = ss;
new_continuum[pp].point = ((uint32_t) (digest[3 + nn * 4] & 0xFF) << 24)
| ((uint32_t) (digest[2 + nn * 4] & 0xFF) << 16)
| ((uint32_t) (digest[1 + nn * 4] & 0xFF) << 8)
| (digest[0 + nn * 4] & 0xFF);
}
}
}
qsort(new_continuum, pp, sizeof *new_continuum, continuum_item_cmp);
old_continuum = cfg->continuum;
cfg->continuum = new_continuum;
cfg->ncontinuum = pp;
free(old_continuum);
return 1;
}
