blob: 6b75fa598bc09a4e98c2afa7c73d06503da9eb96 [file] [log] [blame] [raw]
/*
* Copyright (C) Igor Sysoev
*/
#include <ngx_config.h>
#include <ngx_core.h>
ngx_int_t
ngx_hash_init(ngx_hash_t *hash, ngx_pool_t *pool, void *names, ngx_uint_t nelts)
{
u_char *p;
ngx_str_t *name, *bucket;
ngx_uint_t i, n, key, size, best, *test, buckets, min_buckets;
if (nelts == 0) {
for (name = (ngx_str_t *) names;
name->len;
name = (ngx_str_t *) ((char *) name + hash->bucket_size))
{
nelts++;
}
}
test = ngx_alloc(hash->max_size * sizeof(ngx_uint_t), pool->log);
if (test == NULL) {
return NGX_ERROR;
}
min_buckets = hash->bucket_limit + 1;
#if (NGX_SUPPRESS_WARN)
best = 0;
#endif
for (size = 1; size < hash->max_size; size++) {
buckets = 0;
for (i = 0; i < size; i++) {
test[i] = 0;
}
for (n = 0, name = (ngx_str_t *) names;
n < nelts;
n++, name = (ngx_str_t *) ((char *) name + hash->bucket_size))
{
key = 0;
for (i = 0; i < name->len; i++) {
key += ngx_tolower(name->data[i]);
}
key %= size;
if (test[key] == hash->bucket_limit) {
break;
}
test[key]++;
if (buckets < test[key]) {
buckets = test[key];
}
}
if (n == nelts) {
if (min_buckets > buckets) {
min_buckets = buckets;
best = size;
}
if (hash->bucket_limit == 1) {
break;
}
}
}
if (min_buckets == hash->bucket_limit + 1) {
ngx_log_error(NGX_LOG_EMERG, pool->log, 0,
"could not build the %s hash, you should increase "
"either %s_size: %i or %s_bucket_limit: %i",
hash->name, hash->name, hash->max_size,
hash->name, hash->bucket_limit);
ngx_free(test);
return NGX_ERROR;
}
hash->buckets = ngx_pcalloc(pool, best * hash->bucket_size);
if (hash->buckets == NULL) {
ngx_free(test);
return NGX_ERROR;
}
if (hash->bucket_limit != 1) {
for (i = 0; i < best; i++) {
test[i] = 0;
}
for (n = 0, name = (ngx_str_t *) names;
n < nelts;
n++, name = (ngx_str_t *) ((char *) name + hash->bucket_size))
{
key = 0;
for (i = 0; i < name->len; i++) {
key += ngx_tolower(name->data[i]);
}
key %= best;
test[key]++;
}
for (i = 0; i < best; i++) {
if (test[i] == 0) {
continue;
}
bucket = ngx_palloc(pool, test[i] * hash->bucket_size);
if (bucket == NULL) {
ngx_free(test);
return NGX_ERROR;
}
hash->buckets[i] = bucket;
bucket->len = 0;
}
}
for (n = 0, name = (ngx_str_t *) names;
n < nelts;
n++, name = (ngx_str_t *) ((char *) name + hash->bucket_size))
{
key = 0;
for (i = 0; i < name->len; i++) {
key += ngx_tolower(name->data[i]);
}
key %= best;
if (hash->bucket_limit == 1) {
p = (u_char *) hash->buckets + key * hash->bucket_size;
ngx_memcpy(p, name, hash->bucket_size);
continue;
}
for (bucket = hash->buckets[key];
bucket->len;
bucket = (ngx_str_t *) ((char *) bucket + hash->bucket_size))
{
bucket->len &= 0x7fffffff;
}
ngx_memcpy(bucket, name, hash->bucket_size);
bucket->len |= 0x80000000;
}
ngx_free(test);
hash->hash_size = best;
hash->min_buckets = min_buckets;
return NGX_OK;
}