This commit is contained in:
Ben V. Brown
2022-06-21 20:51:47 +10:00
parent 9fb063ba29
commit 51ad2f71c7
3 changed files with 29 additions and 25 deletions

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@@ -0,0 +1,29 @@
#pragma once
#include <stdint.h>
#define DEFAULT_POLY 0x973afb51
template <uint32_t polynomial = DEFAULT_POLY> struct CRC32Table {
constexpr CRC32Table() : table() {
for (uint32_t i = 0; i < 256; i++) {
uint32_t c = i;
for (auto j = 0; j < 8; j++) {
if (c & 1) {
c = polynomial ^ (c >> 1);
} else {
c >>= 1;
}
}
table[i] = c;
}
}
uint32_t table[256];
uint32_t computeCRC32(uint32_t initial, const uint8_t *buf, int len) {
uint32_t c = initial ^ 0xFFFFFFFF;
for (auto i = 0; i < len; ++i) {
c = table[(c ^ buf[i]) & 0xFF] ^ (c >> 8);
}
return c ^ 0xFFFFFFFF;
}
};

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@@ -1,19 +0,0 @@
#include "crc16.hpp"
#define POLYNOM 0x8005
unsigned int crc16(unsigned int crcValue, unsigned char newByte) {
unsigned char i;
for (i = 0; i < 8; i++) {
if (((crcValue & 0x8000) >> 8) ^ (newByte & 0x80)) {
crcValue = (crcValue << 1) ^ POLYNOM;
} else {
crcValue = (crcValue << 1);
}
newByte <<= 1;
}
return crcValue;
}

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@@ -1,6 +0,0 @@
#ifndef DRIVERS_CRC16_H_
#define DRIVERS_CRC16_H_
unsigned int crc16(unsigned int crcValue, unsigned char newByte);
#endif