e6885a4515
Move crc implementation to own directory and reduce clutter in lib/os. Signed-off-by: Anas Nashif <anas.nashif@intel.com>
77 lines
1.3 KiB
C
77 lines
1.3 KiB
C
/*
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* Copyright (c) 2017 Intel Corporation.
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <zephyr/sys/crc.h>
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uint16_t crc16(uint16_t poly, uint16_t seed, const uint8_t *src, size_t len)
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{
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uint16_t crc = seed;
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size_t i, j;
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for (i = 0; i < len; i++) {
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crc ^= (uint16_t)(src[i] << 8U);
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for (j = 0; j < 8; j++) {
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if (crc & 0x8000UL) {
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crc = (crc << 1U) ^ poly;
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} else {
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crc = crc << 1U;
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}
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}
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}
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return crc;
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}
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uint16_t crc16_reflect(uint16_t poly, uint16_t seed, const uint8_t *src, size_t len)
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{
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uint16_t crc = seed;
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size_t i, j;
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for (i = 0; i < len; i++) {
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crc ^= (uint16_t)src[i];
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for (j = 0; j < 8; j++) {
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if (crc & 0x0001UL) {
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crc = (crc >> 1U) ^ poly;
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} else {
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crc = crc >> 1U;
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}
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}
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}
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return crc;
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}
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uint16_t crc16_ccitt(uint16_t seed, const uint8_t *src, size_t len)
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{
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for (; len > 0; len--) {
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uint8_t e, f;
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e = seed ^ *src++;
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f = e ^ (e << 4);
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seed = (seed >> 8) ^ ((uint16_t)f << 8) ^ ((uint16_t)f << 3) ^ ((uint16_t)f >> 4);
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}
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return seed;
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}
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uint16_t crc16_itu_t(uint16_t seed, const uint8_t *src, size_t len)
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{
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for (; len > 0; len--) {
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seed = (seed >> 8U) | (seed << 8U);
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seed ^= *src++;
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seed ^= (seed & 0xffU) >> 4U;
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seed ^= seed << 12U;
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seed ^= (seed & 0xffU) << 5U;
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}
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return seed;
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}
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