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    1 /**
    2  * @page c_crc CRC32 API
    3  *
    4  * @subpage le_crc.h "API Reference"
    5  *
    6  * <HR>
    7  *
    8  * This module provides APIs for computing CRC of a binary buffer.
    9  *
   10  * CRC (Cyclic Redundancy Check) are used to verify the integrity of data, like file, messages, etc...
   11  *
   12  * @section Crc32 Computing a CRC32
   13  *
   14  *   - @c le_crc_Crc32() - Compute the CRC32 of a memory buffer
   15  *
   16  * The CRC32 is computed by the function @ref le_crc_Crc32. It takes a base buffer address, a length
   17  * and a CRC32. When the CRC32 is expected to be first computed, the value @ref LE_CRC_START_CRC32
   18  * needs to be set as crc32 value.
   19  *
   20  * @note It is possible to compute a "global" CRC32 of a huge amount of data by splitting into small
   21  * blocks and continue computing the CRC32 on each one.
   22  *
   23  * This code compute the whole CRC32 of amount of data splitted into an array of small blocks:
   24  * @code
   25  * #define MAX_BLOCKS 4  // Maximum number of blocks
   26  *
   27  * typedef struct
   28  * {
   29  *     size_t   blockSize;  // size of the block
   30  *     uint8_t *blockPtr;   // pointer of the data
   31  * }
   32  * block_t;
   33  *
   34  * uint32_t ComputeArrayCRC32
   35  * (
   36  *     block_t blockArray[]
   37  * )
   38  * {
   39  *     uint32_t crc = LE_CRC_START_CRC32;  // New CRC initialized
   40  *     int iBlock;
   41  *
   42  *     for (iBlock = 0; iBlock < MAX_BLOCKS; iBlock++)
   43  *     {
   44  *         if (blockArray[iBlock].blockPtr)
   45  *         {
   46  *             crc = le_crc_Crc32(blockArray[iBlock].blockPtr,
   47  *                                blockArray[iBlock].blockSize,
   48  *                                crc);
   49  *         }
   50  *     }
   51  *     return crc;
   52  * }
   53  * @endcode
   54  *
   55  * <HR>
   56  *
   57  * Copyright (C) Sierra Wireless Inc.
   58  *
   59  */
   60 
   61 //--------------------------------------------------------------------------------------------------
   62 /** @file le_crc.h
   63  *
   64  * Legato @ref c_crc include file.
   65  *
   66  * Copyright (C) Sierra Wireless Inc.
   67  */
   68 //--------------------------------------------------------------------------------------------------
   69 
   70 #ifndef LEGATO_CRC_INCLUDE_GUARD
   71 #define LEGATO_CRC_INCLUDE_GUARD
   72 
   73 #ifndef LE_COMPONENT_NAME
   74 #define LE_COMPONENT_NAME
   75 #endif
   76 
   77 //--------------------------------------------------------------------------------------------------
   78 /**
   79  * Initial value for CRC32 calculation
   80  */
   81 //--------------------------------------------------------------------------------------------------
   82 #define LE_CRC_START_CRC32         0xFFFFFFFFU
   83 
   84 //--------------------------------------------------------------------------------------------------
   85 /**
   86  * This function is used to calculate a CRC-32
   87  *
   88  * @return
   89  *      - 32-bit CRC
   90  */
   91 //--------------------------------------------------------------------------------------------------
   92 uint32_t le_crc_Crc32
   93 (
   94     const uint8_t   *addressPtr,    ///< [IN] Input buffer
   95     size_t           size,          ///< [IN] Number of bytes to read
   96     uint32_t         crc            ///< [IN] Starting CRC seed
   97 );
   98 
   99 #endif // LEGATO_CRC_INCLUDE_GUARD
le_crc_Crc32
uint32_t le_crc_Crc32(const uint8_t *addressPtr, size_t size, uint32_t crc)