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fit_decoder
0.1.0
A high-performance Elixir library for decoding Garmin .fit files using a C++ NIF.
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c_src/fit_sdk/cpp/fit_crc.cpp
/////////////////////////////////////////////////////////////////////////////////////////////
// Copyright 2025 Garmin International, Inc.
// Licensed under the Flexible and Interoperable Data Transfer (FIT) Protocol License; you
// may not use this file except in compliance with the Flexible and Interoperable Data
// Transfer (FIT) Protocol License.
/////////////////////////////////////////////////////////////////////////////////////////////
// ****WARNING**** This file is auto-generated! Do NOT edit this file.
// Profile Version = 21.171.0Release
// Tag = production/release/21.171.0-0-g57fed75
/////////////////////////////////////////////////////////////////////////////////////////////
#include "fit_crc.hpp"
namespace fit
{
FIT_UINT16 CRC::Get16(FIT_UINT16 crc, FIT_UINT8 byte)
{
static const FIT_UINT16 crc_table[16] =
{
0x0000, 0xCC01, 0xD801, 0x1400, 0xF001, 0x3C00, 0x2800, 0xE401,
0xA001, 0x6C00, 0x7800, 0xB401, 0x5000, 0x9C01, 0x8801, 0x4400
};
FIT_UINT16 tmp;
// compute checksum of lower four bits of byte
tmp = crc_table[crc & 0xF];
crc = (crc >> 4) & 0x0FFF;
crc = crc ^ tmp ^ crc_table[byte & 0xF];
// now compute checksum of upper four bits of byte
tmp = crc_table[crc & 0xF];
crc = (crc >> 4) & 0x0FFF;
crc = crc ^ tmp ^ crc_table[(byte >> 4) & 0xF];
return crc;
}
FIT_UINT16 CRC::Calc16(const volatile void *data, FIT_UINT32 size)
{
FIT_UINT16 crc = 0;
FIT_BYTE *data_ptr = (FIT_BYTE *)data;
while (size)
{
crc = CRC::Get16(crc, *data_ptr);
data_ptr++;
size--;
}
return crc;
}
} // namespace fit
#if defined(FIT_CPP_INCLUDE_C)
// Include C Implementation
#include "fit_crc.c"
#endif