fnv_hash.c

00001 /*
00002  * Copyright (c) 2016-2017, Arm Limited and affiliates.
00003  * SPDX-License-Identifier: Apache-2.0
00004  *
00005  * Licensed under the Apache License, Version 2.0 (the "License");
00006  * you may not use this file except in compliance with the License.
00007  * You may obtain a copy of the License at
00008  *
00009  *     http://www.apache.org/licenses/LICENSE-2.0
00010  *
00011  * Unless required by applicable law or agreed to in writing, software
00012  * distributed under the License is distributed on an "AS IS" BASIS,
00013  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00014  * See the License for the specific language governing permissions and
00015  * limitations under the License.
00016  */
00017 
00018 #include "nsconfig.h"
00019 #include "fnv_hash.h"
00020 
00021 #if 0
00022 uint32_t fnv_hash_1a_32_block(const uint8_t *data, uint16_t len)
00023 {
00024     return fnv_hash_1a_32_block_update(UINT32_C(0x811c9dc5), data, len);
00025 }
00026 
00027 uint32_t fnv_hash_1a_32_block_update(uint32_t hash, const uint8_t *data, uint16_t len)
00028 {
00029     for (; len; --len) {
00030         hash ^= *data++;
00031         hash *= UINT32_C(0x01000193);
00032     }
00033     return hash;
00034 }
00035 #endif
00036 
00037 uint32_t fnv_hash_1a_32_reverse_block(const uint8_t *data, uint16_t len)
00038 {
00039     return fnv_hash_1a_32_reverse_block_update(UINT32_C(0x811c9dc5), data, len);
00040 }
00041 
00042 uint32_t fnv_hash_1a_32_reverse_block_update(uint32_t hash, const uint8_t *data, uint16_t len)
00043 {
00044     for (data += len; len; --len) {
00045         hash ^= *--data;
00046         hash *= UINT32_C(0x01000193);
00047     }
00048     return hash;
00049 }