lfs_util.c

00001 /*
00002  * lfs util functions
00003  *
00004  * Copyright (c) 2017 ARM Limited
00005  *
00006  * Licensed under the Apache License, Version 2.0 (the "License");
00007  * you may not use this file except in compliance with the License.
00008  * You may obtain a copy of the License at
00009  *
00010  *     http://www.apache.org/licenses/LICENSE-2.0
00011  *
00012  * Unless required by applicable law or agreed to in writing, software
00013  * distributed under the License is distributed on an "AS IS" BASIS,
00014  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00015  * See the License for the specific language governing permissions and
00016  * limitations under the License.
00017  */
00018 #include "lfs_util.h"
00019 
00020 
00021 void lfs_crc(uint32_t *restrict crc, const void *buffer, size_t size) {
00022     static const uint32_t rtable[16] = {
00023         0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac,
00024         0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c,
00025         0xedb88320, 0xf00f9344, 0xd6d6a3e8, 0xcb61b38c,
00026         0x9b64c2b0, 0x86d3d2d4, 0xa00ae278, 0xbdbdf21c,
00027     };
00028 
00029     const uint8_t *data = buffer;
00030 
00031     for (size_t i = 0; i < size; i++) {
00032         *crc = (*crc >> 4) ^ rtable[(*crc ^ (data[i] >> 0)) & 0xf];
00033         *crc = (*crc >> 4) ^ rtable[(*crc ^ (data[i] >> 4)) & 0xf];
00034     }
00035 }
00036