Sources/crc32iso3309.c

/*
 Copyright (c) 2015-2021 Spotify AB.

 Licensed to the Apache Software Foundation (ASF) under one
 or more contributor license agreements.  See the NOTICE file
 distributed with this work for additional information
 regarding copyright ownership.  The ASF licenses this file
 to you 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 "crc32iso3309.h"

/**
 Algorithms is taken from RFC-1952. Appendix: Sample CRC Code
 */

/* Table of CRCs of all 8-bit messages. */
static const uint32_t crc_table[] = {
    0x00000000U, 0x77073096U, 0xee0e612cU, 0x990951baU,
    0x076dc419U, 0x706af48fU, 0xe963a535U, 0x9e6495a3U,
    0x0edb8832U, 0x79dcb8a4U, 0xe0d5e91eU, 0x97d2d988U,
    0x09b64c2bU, 0x7eb17cbdU, 0xe7b82d07U, 0x90bf1d91U,
    0x1db71064U, 0x6ab020f2U, 0xf3b97148U, 0x84be41deU,
    0x1adad47dU, 0x6ddde4ebU, 0xf4d4b551U, 0x83d385c7U,
    0x136c9856U, 0x646ba8c0U, 0xfd62f97aU, 0x8a65c9ecU,
    0x14015c4fU, 0x63066cd9U, 0xfa0f3d63U, 0x8d080df5U,
    0x3b6e20c8U, 0x4c69105eU, 0xd56041e4U, 0xa2677172U,
    0x3c03e4d1U, 0x4b04d447U, 0xd20d85fdU, 0xa50ab56bU,
    0x35b5a8faU, 0x42b2986cU, 0xdbbbc9d6U, 0xacbcf940U,
    0x32d86ce3U, 0x45df5c75U, 0xdcd60dcfU, 0xabd13d59U,
    0x26d930acU, 0x51de003aU, 0xc8d75180U, 0xbfd06116U,
    0x21b4f4b5U, 0x56b3c423U, 0xcfba9599U, 0xb8bda50fU,
    0x2802b89eU, 0x5f058808U, 0xc60cd9b2U, 0xb10be924U,
    0x2f6f7c87U, 0x58684c11U, 0xc1611dabU, 0xb6662d3dU,
    0x76dc4190U, 0x01db7106U, 0x98d220bcU, 0xefd5102aU,
    0x71b18589U, 0x06b6b51fU, 0x9fbfe4a5U, 0xe8b8d433U,
    0x7807c9a2U, 0x0f00f934U, 0x9609a88eU, 0xe10e9818U,
    0x7f6a0dbbU, 0x086d3d2dU, 0x91646c97U, 0xe6635c01U,
    0x6b6b51f4U, 0x1c6c6162U, 0x856530d8U, 0xf262004eU,
    0x6c0695edU, 0x1b01a57bU, 0x8208f4c1U, 0xf50fc457U,
    0x65b0d9c6U, 0x12b7e950U, 0x8bbeb8eaU, 0xfcb9887cU,
    0x62dd1ddfU, 0x15da2d49U, 0x8cd37cf3U, 0xfbd44c65U,
    0x4db26158U, 0x3ab551ceU, 0xa3bc0074U, 0xd4bb30e2U,
    0x4adfa541U, 0x3dd895d7U, 0xa4d1c46dU, 0xd3d6f4fbU,
    0x4369e96aU, 0x346ed9fcU, 0xad678846U, 0xda60b8d0U,
    0x44042d73U, 0x33031de5U, 0xaa0a4c5fU, 0xdd0d7cc9U,
    0x5005713cU, 0x270241aaU, 0xbe0b1010U, 0xc90c2086U,
    0x5768b525U, 0x206f85b3U, 0xb966d409U, 0xce61e49fU,
    0x5edef90eU, 0x29d9c998U, 0xb0d09822U, 0xc7d7a8b4U,
    0x59b33d17U, 0x2eb40d81U, 0xb7bd5c3bU, 0xc0ba6cadU,
    0xedb88320U, 0x9abfb3b6U, 0x03b6e20cU, 0x74b1d29aU,
    0xead54739U, 0x9dd277afU, 0x04db2615U, 0x73dc1683U,
    0xe3630b12U, 0x94643b84U, 0x0d6d6a3eU, 0x7a6a5aa8U,
    0xe40ecf0bU, 0x9309ff9dU, 0x0a00ae27U, 0x7d079eb1U,
    0xf00f9344U, 0x8708a3d2U, 0x1e01f268U, 0x6906c2feU,
    0xf762575dU, 0x806567cbU, 0x196c3671U, 0x6e6b06e7U,
    0xfed41b76U, 0x89d32be0U, 0x10da7a5aU, 0x67dd4accU,
    0xf9b9df6fU, 0x8ebeeff9U, 0x17b7be43U, 0x60b08ed5U,
    0xd6d6a3e8U, 0xa1d1937eU, 0x38d8c2c4U, 0x4fdff252U,
    0xd1bb67f1U, 0xa6bc5767U, 0x3fb506ddU, 0x48b2364bU,
    0xd80d2bdaU, 0xaf0a1b4cU, 0x36034af6U, 0x41047a60U,
    0xdf60efc3U, 0xa867df55U, 0x316e8eefU, 0x4669be79U,
    0xcb61b38cU, 0xbc66831aU, 0x256fd2a0U, 0x5268e236U,
    0xcc0c7795U, 0xbb0b4703U, 0x220216b9U, 0x5505262fU,
    0xc5ba3bbeU, 0xb2bd0b28U, 0x2bb45a92U, 0x5cb36a04U,
    0xc2d7ffa7U, 0xb5d0cf31U, 0x2cd99e8bU, 0x5bdeae1dU,
    0x9b64c2b0U, 0xec63f226U, 0x756aa39cU, 0x026d930aU,
    0x9c0906a9U, 0xeb0e363fU, 0x72076785U, 0x05005713U,
    0x95bf4a82U, 0xe2b87a14U, 0x7bb12baeU, 0x0cb61b38U,
    0x92d28e9bU, 0xe5d5be0dU, 0x7cdcefb7U, 0x0bdbdf21U,
    0x86d3d2d4U, 0xf1d4e242U, 0x68ddb3f8U, 0x1fda836eU,
    0x81be16cdU, 0xf6b9265bU, 0x6fb077e1U, 0x18b74777U,
    0x88085ae6U, 0xff0f6a70U, 0x66063bcaU, 0x11010b5cU,
    0x8f659effU, 0xf862ae69U, 0x616bffd3U, 0x166ccf45U,
    0xa00ae278U, 0xd70dd2eeU, 0x4e048354U, 0x3903b3c2U,
    0xa7672661U, 0xd06016f7U, 0x4969474dU, 0x3e6e77dbU,
    0xaed16a4aU, 0xd9d65adcU, 0x40df0b66U, 0x37d83bf0U,
    0xa9bcae53U, 0xdebb9ec5U, 0x47b2cf7fU, 0x30b5ffe9U,
    0xbdbdf21cU, 0xcabac28aU, 0x53b39330U, 0x24b4a3a6U, 
    0xbad03605U, 0xcdd70693U, 0x54de5729U, 0x23d967bfU, 
    0xb3667a2eU, 0xc4614ab8U, 0x5d681b02U, 0x2a6f2b94U, 
    0xb40bbe37U, 0xc30c8ea1U, 0x5a05df1bU, 0x2d02ef8dU
};

/*
 Update a running crc with the bytes buf[0..len-1] and return
 the updated crc. The crc should be initialized to zero. Pre- and
 post-conditioning (one's complement) is performed within this
 function so it shouldn't be done by the caller. Usage example:

 uint32_t crc = 0L;

 while (read_buffer(buffer, length) != EOF) {
 crc = update_crc(crc, buffer, length);
 }
 if (crc != original_crc) error();
 */
static uint32_t update_crc(uint32_t crc, const uint8_t *buf, size_t len)
{
    uint32_t c = crc ^ 0xffFFffFFU;

    for (size_t n = 0; n < len; ++n) {
        c = crc_table[(c ^ buf[n]) & 0xFF] ^ (c >> 8);
    }
    return c ^ 0xffFFffFFU;
}

/* Return the CRC of the bytes buf[0..len-1]. */
uint32_t spt_crc32(const uint8_t *buf, size_t len)
{
    return update_crc(0L, buf, len);
}