keychron_qmk_firmware/quantum/crc.h
Stefan Kerkmann ef92c9ee2c
Add CRC8 calculation subsystem to quantum (#12641)
* Intended usage is data validation in split transport code.
* Default space efficient algorithm.
* Opt-in fast table based algorithmn with #define CRC8_USE_TABLE switch.
* Define switches for size and speed optimized versions, the default is size
  optimized by using uint_least8_t as datatype for calculations.
  * #define CRC8_OPTIMIZE_SPEED uses uint_fast8_t as datatype for
    calculations, this only affects 32-bit Archs like ARM and RISC-V.
* Placeholder crc_init() function for hardware backed crc calculation,
  not implemented yet.
2021-06-18 00:09:43 +01:00

44 lines
1.3 KiB
C

/* Copyright 2021 QMK
*
* 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 2 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.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
#include "quantum.h"
/**
* The type of the CRC values.
*
* This type must be big enough to contain at least 8 bits.
*/
#if defined(CRC8_OPTIMIZE_SPEED)
typedef uint_fast8_t crc_t;
#else
typedef uint_least8_t crc_t;
#endif
/**
* Initialize crc subsystem.
*/
__attribute__((weak)) void crc_init(void);
/**
* Generate CRC8 value from given data.
*
* \param[in] data Pointer to a buffer of \a data_len bytes.
* \param[in] data_len Number of bytes in the \a data buffer.
* \return The calculated crc value.
*/
__attribute__((weak)) uint8_t crc8(const void *data, size_t data_len);