138 lines
4.1 KiB
C
138 lines
4.1 KiB
C
|
/**
|
||
|
|
* \file
|
||
|
|
*
|
||
|
|
* \brief 32-bit CRC header.
|
||
|
|
*
|
||
|
|
* Copyright (C) 2013-2015 Atmel Corporation. All rights reserved.
|
||
|
|
*
|
||
|
|
* \asf_license_start
|
||
|
|
*
|
||
|
|
* \page License
|
||
|
|
*
|
||
|
|
* Redistribution and use in source and binary forms, with or without
|
||
|
|
* modification, are permitted provided that the following conditions are met:
|
||
|
|
*
|
||
|
|
* 1. Redistributions of source code must retain the above copyright notice,
|
||
|
|
* this list of conditions and the following disclaimer.
|
||
|
|
*
|
||
|
|
* 2. Redistributions in binary form must reproduce the above copyright notice,
|
||
|
|
* this list of conditions and the following disclaimer in the documentation
|
||
|
|
* and/or other materials provided with the distribution.
|
||
|
|
*
|
||
|
|
* 3. The name of Atmel may not be used to endorse or promote products derived
|
||
|
|
* from this software without specific prior written permission.
|
||
|
|
*
|
||
|
|
* 4. This software may only be redistributed and used in connection with an
|
||
|
|
* Atmel microcontroller product.
|
||
|
|
*
|
||
|
|
* THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED
|
||
|
|
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
|
||
|
|
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
|
||
|
|
* EXPRESSLY AND SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR
|
||
|
|
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
||
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
||
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
||
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
|
||
|
|
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
|
||
|
|
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
||
|
|
* POSSIBILITY OF SUCH DAMAGE.
|
||
|
|
*
|
||
|
|
* \asf_license_stop
|
||
|
|
*
|
||
|
|
*/
|
||
|
|
/*
|
||
|
|
* Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
|
||
|
|
*/
|
||
|
|
|
||
|
|
#ifndef CRC32_H
|
||
|
|
#define CRC32_H
|
||
|
|
|
||
|
|
|
||
|
|
#include <compiler.h>
|
||
|
|
|
||
|
|
|
||
|
|
/**
|
||
|
|
* \defgroup common_services_crc32 CRC-32 calculation service
|
||
|
|
*
|
||
|
|
* See \ref common_services_crc32_quickstart.
|
||
|
|
*
|
||
|
|
* This service enables the user to calculate 32-bit CRC using the polynomial
|
||
|
|
* defined in the IEEE 802.3 standard, with support for multiple data blocks
|
||
|
|
* of arbitrary sizes, and any alignment in memory.
|
||
|
|
*
|
||
|
|
* @{
|
||
|
|
*/
|
||
|
|
|
||
|
|
|
||
|
|
//! Type to contain 32-bit CRC.
|
||
|
|
typedef uint32_t crc32_t;
|
||
|
|
|
||
|
|
|
||
|
|
#ifdef __cplusplus
|
||
|
|
extern "C" {
|
||
|
|
#endif
|
||
|
|
|
||
|
|
enum status_code crc32_recalculate(const void *data, size_t length, crc32_t *crc);
|
||
|
|
|
||
|
|
#ifdef __cplusplus
|
||
|
|
}
|
||
|
|
#endif
|
||
|
|
|
||
|
|
|
||
|
|
/**
|
||
|
|
* \brief Calculate 32-bit CRC for initial block
|
||
|
|
*
|
||
|
|
* This function calculates the CRC for the specified data block, which may be
|
||
|
|
* first of an arbitrary number of blocks.
|
||
|
|
*
|
||
|
|
* The actual calculation is done in \ref crc32_recalculate(), while this
|
||
|
|
* function just sets up the initial CRC value.
|
||
|
|
*
|
||
|
|
* \param[in] data Address of data.
|
||
|
|
* \param[in] length Length of data.
|
||
|
|
* \param[out] crc Address of variable to store the calculated CRC in.
|
||
|
|
*
|
||
|
|
* \return Status of calculation.
|
||
|
|
* \retval STATUS_OK if calculation succeeded.
|
||
|
|
* \retval <other> if calculation failed somehow.
|
||
|
|
*
|
||
|
|
* \note To calculate the CRC of multiple blocks, use this function first, then
|
||
|
|
* \ref crc32_recalculate() for the following blocks.
|
||
|
|
*/
|
||
|
|
static inline enum status_code crc32_calculate(const void *data, size_t length,
|
||
|
|
crc32_t *crc)
|
||
|
|
{
|
||
|
|
*crc = 0;
|
||
|
|
|
||
|
|
return crc32_recalculate(data, length, crc);
|
||
|
|
}
|
||
|
|
|
||
|
|
/** @} */
|
||
|
|
|
||
|
|
/**
|
||
|
|
* \page common_services_crc32_quickstart Quick Start Guide for CRC-32
|
||
|
|
*
|
||
|
|
* To use this service, the user must supply a \ref crc32_t "container" variable
|
||
|
|
* for the CRC and call \ref crc32_calculate() with the parameters for the first
|
||
|
|
* block in the dataset. For subsequent blocks, \ref crc32_recalculate() must be
|
||
|
|
* used.
|
||
|
|
*
|
||
|
|
* \note The user may also initialize the container with a known CRC value and
|
||
|
|
* use that as the "seed" for \ref crc32_recalculate().
|
||
|
|
*
|
||
|
|
*
|
||
|
|
* \section common_services_crc32_quickstart_code Example Code
|
||
|
|
*
|
||
|
|
\code
|
||
|
|
uint8_t block1[10] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
|
||
|
|
uint8_t block2[6] = {0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f};
|
||
|
|
|
||
|
|
crc32_t my_crc;
|
||
|
|
|
||
|
|
crc32_calculate(block1, sizeof(block1), &my_crc);
|
||
|
|
crc32_recalculate(block2, sizeof(block2), &my_crc);
|
||
|
|
\endcode
|
||
|
|
*
|
||
|
|
*/
|
||
|
|
|
||
|
|
#endif // CRC32_H
|