mirror of
https://github.com/DarkFlippers/unleashed-firmware
synced 2024-12-25 04:03:07 +00:00
36 lines
1.1 KiB
C
36 lines
1.1 KiB
C
/* Copyright (C) 2022-2023 Salvatore Sanfilippo -- All Rights Reserved
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* See the LICENSE file for information about the license. */
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#include <stdint.h>
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#include <stddef.h>
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/* CRC8 with the specified initialization value 'init' and
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* polynomial 'poly'. */
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uint8_t crc8(const uint8_t* data, size_t len, uint8_t init, uint8_t poly) {
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uint8_t crc = init;
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size_t i, j;
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for(i = 0; i < len; i++) {
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crc ^= data[i];
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for(j = 0; j < 8; j++) {
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if((crc & 0x80) != 0)
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crc = (uint8_t)((crc << 1) ^ poly);
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else
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crc <<= 1;
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}
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}
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return crc;
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}
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/* Sum all the specified bytes modulo 256.
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* Initialize the sum with 'init' (usually 0). */
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uint8_t sum_bytes(const uint8_t* data, size_t len, uint8_t init) {
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for(size_t i = 0; i < len; i++) init += data[i];
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return init;
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}
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/* Perform the bitwise xor of all the specified bytes.
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* Initialize xor value with 'init' (usually 0). */
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uint8_t xor_bytes(const uint8_t* data, size_t len, uint8_t init) {
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for(size_t i = 0; i < len; i++) init ^= data[i];
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return init;
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}
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