text: /**
   * \file
   *
   * \brief 32-bit CRC header.
   *
   * Copyright (C) 2013-2014 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