nuttx/libs/libc/misc/lib_crc8.c
Alin Jerpelea 231b8518b7 NuttX: Ken Pettit: update licenses to Apache
Ken Pettit has submitted the ICLA and we can migrate the licenses
 to Apache.

Sebastien Lorquet has submitted the ICLA and we can migrate the licenses
 to Apache.

Gregory Nutt has submitted the SGA and we can migrate the licenses
 to Apache.

Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
2021-04-10 06:42:19 -05:00

131 lines
4.6 KiB
C

/****************************************************************************
* libs/libc/misc/lib_crc8.c
*
* 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <sys/types.h>
#include <stdint.h>
#include <crc8.h>
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* CRC8 table generated with:
*
* #define POLY 0xB2 ((uint8_t) 0x14D) ^ 0xFF
*
* printf(" ");
* for (y = 0; y < 256; y++)
* {
* crc = y;
* for (x = 0; x < 8; x++)
* {
* crc = (crc & 1) ? POLY ^ (crc >> 1) : crc >> 1;
* }
*
* printf("0x%02X, ", crc);
* if ((y & 0x07) == 0x7)
* {
* printf("\n ");
* }
* }
*
****************************************************************************/
static const uint8_t crc8_tab[256] =
{
0x00, 0x3e, 0x7c, 0x42, 0xf8, 0xc6, 0x84, 0xba,
0x95, 0xab, 0xe9, 0xd7, 0x6d, 0x53, 0x11, 0x2f,
0x4f, 0x71, 0x33, 0x0d, 0xb7, 0x89, 0xcb, 0xf5,
0xda, 0xe4, 0xa6, 0x98, 0x22, 0x1c, 0x5e, 0x60,
0x9e, 0xa0, 0xe2, 0xdc, 0x66, 0x58, 0x1a, 0x24,
0x0b, 0x35, 0x77, 0x49, 0xf3, 0xcd, 0x8f, 0xb1,
0xd1, 0xef, 0xad, 0x93, 0x29, 0x17, 0x55, 0x6b,
0x44, 0x7a, 0x38, 0x06, 0xbc, 0x82, 0xc0, 0xfe,
0x59, 0x67, 0x25, 0x1b, 0xa1, 0x9f, 0xdd, 0xe3,
0xcc, 0xf2, 0xb0, 0x8e, 0x34, 0x0a, 0x48, 0x76,
0x16, 0x28, 0x6a, 0x54, 0xee, 0xd0, 0x92, 0xac,
0x83, 0xbd, 0xff, 0xc1, 0x7b, 0x45, 0x07, 0x39,
0xc7, 0xf9, 0xbb, 0x85, 0x3f, 0x01, 0x43, 0x7d,
0x52, 0x6c, 0x2e, 0x10, 0xaa, 0x94, 0xd6, 0xe8,
0x88, 0xb6, 0xf4, 0xca, 0x70, 0x4e, 0x0c, 0x32,
0x1d, 0x23, 0x61, 0x5f, 0xe5, 0xdb, 0x99, 0xa7,
0xb2, 0x8c, 0xce, 0xf0, 0x4a, 0x74, 0x36, 0x08,
0x27, 0x19, 0x5b, 0x65, 0xdf, 0xe1, 0xa3, 0x9d,
0xfd, 0xc3, 0x81, 0xbf, 0x05, 0x3b, 0x79, 0x47,
0x68, 0x56, 0x14, 0x2a, 0x90, 0xae, 0xec, 0xd2,
0x2c, 0x12, 0x50, 0x6e, 0xd4, 0xea, 0xa8, 0x96,
0xb9, 0x87, 0xc5, 0xfb, 0x41, 0x7f, 0x3d, 0x03,
0x63, 0x5d, 0x1f, 0x21, 0x9b, 0xa5, 0xe7, 0xd9,
0xf6, 0xc8, 0x8a, 0xb4, 0x0e, 0x30, 0x72, 0x4c,
0xeb, 0xd5, 0x97, 0xa9, 0x13, 0x2d, 0x6f, 0x51,
0x7e, 0x40, 0x02, 0x3c, 0x86, 0xb8, 0xfa, 0xc4,
0xa4, 0x9a, 0xd8, 0xe6, 0x5c, 0x62, 0x20, 0x1e,
0x31, 0x0f, 0x4d, 0x73, 0xc9, 0xf7, 0xb5, 0x8b,
0x75, 0x4b, 0x09, 0x37, 0x8d, 0xb3, 0xf1, 0xcf,
0xe0, 0xde, 0x9c, 0xa2, 0x18, 0x26, 0x64, 0x5a,
0x3a, 0x04, 0x46, 0x78, 0xc2, 0xfc, 0xbe, 0x80,
0xaf, 0x91, 0xd3, 0xed, 0x57, 0x69, 0x2b, 0x15
};
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: crc8part
*
* Description:
* Continue CRC calculation on a part of the buffer.
*
****************************************************************************/
uint8_t crc8part(FAR const uint8_t *src, size_t len, uint8_t crc8val)
{
size_t i;
crc8val ^= 0xff;
for (i = 0; i < len; i++)
{
crc8val = crc8_tab[crc8val ^ src[i]];
}
return crc8val ^ 0xff;
}
/****************************************************************************
* Name: crc8
*
* Description:
* Return a 8-bit CRC of the contents of the 'src' buffer, length 'len'
* using a CRC with the polynomial x^8+x^6+x^3+x^2+1 (Koopman, et al.
* "0xA6" polynomial).
*
****************************************************************************/
uint8_t crc8(FAR const uint8_t *src, size_t len)
{
return crc8part(src, len, 0);
}