esp-idf/components/bt/common/osi/hash_functions.c

65 wiersze
1.7 KiB
C

/******************************************************************************
*
* Copyright (C) 2014 Google, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
******************************************************************************/
#include <string.h>
#include "osi/hash_functions.h"
hash_index_t hash_function_naive(const void *key)
{
return (hash_index_t)key;
}
hash_index_t hash_function_integer(const void *key)
{
return ((hash_index_t)key) * 2654435761;
}
hash_index_t hash_function_pointer(const void *key)
{
return ((hash_index_t)key) * 2654435761;
}
hash_index_t hash_function_string(const void *key)
{
hash_index_t hash = 5381;
const char *name = (const char *)key;
size_t string_len = strlen(name);
for (size_t i = 0; i < string_len; ++i) {
hash = ((hash << 5) + hash ) + name[i];
}
return hash;
}
void hash_function_blob(const unsigned char *s, unsigned int len, hash_key_t h)
{
size_t j;
while (len--) {
j = sizeof(hash_key_t)-1;
while (j) {
h[j] = ((h[j] << 7) | (h[j-1] >> 1)) + h[j];
--j;
}
h[0] = (h[0] << 7) + h[0] + *s++;
}
}