src/base/crc.hh

   1 /*
   2  * Copyright (c) 2017 ARM Limited
   3  * All rights reserved
   4  *
   5  * The license below extends only to copyright in the software and shall
   6  * not be construed as granting a license to any other intellectual
   7  * property including but not limited to intellectual property relating
   8  * to a hardware implementation of the functionality of the software
   9  * licensed hereunder.  You may use the software subject to the license
  10  * terms below provided that you ensure that this notice is replicated
  11  * unmodified and in its entirety in all distributions of the software,
  12  * modified or unmodified, in source code or in binary form.
  13  *
  14  * Redistribution and use in source and binary forms, with or without
  15  * modification, are permitted provided that the following conditions are
  16  * met: redistributions of source code must retain the above copyright
  17  * notice, this list of conditions and the following disclaimer;
  18  * redistributions in binary form must reproduce the above copyright
  19  * notice, this list of conditions and the following disclaimer in the
  20  * documentation and/or other materials provided with the distribution;
  21  * neither the name of the copyright holders nor the names of its
  22  * contributors may be used to endorse or promote products derived from
  23  * this software without specific prior written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  26  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  27  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  28  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  29  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  30  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  31  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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  34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  35  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36  */
  37
  38 #ifndef __BASE_CRC_HH__
  39 #define __BASE_CRC_HH__
  40
  41 #include "base/bitfield.hh"
  42
  43 /**
  44  * Evaluate the CRC32 of the first size bytes of a data buffer,
  45  * using a specific polynomium and an initial value.
  46  * The crc is accomplished by reversing the input, the initial value
  47  * and the output (remainder).
  48  *
  49  * @param data: Input data buffer pointer
  50  * @param crc:  Initial value of the checksum
  51  * @param size: Number of bytes
  52  *
  53  * @return 32-bit remainder of the checksum
  54  *
  55  * @ingroup api_base_utils
  56  */
  57 template <uint32_t Poly>
  58 uint32_t
  59 crc32(const uint8_t* data, uint32_t crc, std::size_t size)
  60 {
  61     uint32_t byte = 0;
  62
  63     crc = reverseBits(crc);
  64     for (auto i = 0; i < size; i++) {
  65         byte = data[i];
  66
  67         // 32-bit reverse
  68         byte = reverseBits(byte);
  69         for (auto j = 0; j <= 7; j++) {
  70             if ((int)(crc ^ byte) < 0) {
  71                 crc = (crc << 1) ^ Poly;
  72             } else {
  73                 crc = crc << 1;
  74             }
  75             byte = byte << 1;
  76         }
  77     }
  78     return reverseBits(crc);
  79 }
  80
  81 #endif // __BASE_CRC_HH__