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