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crc.cpp
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crc.cpp
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/*
* Copyright (C) 2023 Debayan Sutradhar (rnayabed) ([email protected])
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include "crc.h"
namespace CRC
{
uint16_t generateCRC16CCITT(std::span<const unsigned char> bytes)
{
uint16_t result = 0;
for (auto&& byte : bytes)
{
// we xor the MSB of result (u16) with the byte -> we get the index (byte value) to fetch.
// then we xor the whole result with the existing result
result = (result << 8) ^ CRC::CRC16CCITTable[(((result >> 8) ^ byte))];
}
return result;
}
}