src/Util/CRC.hpp

   1 /*
   2 Copyright_License {
   3
   4   XCSoar Glide Computer - http://www.xcsoar.org/
   5   Copyright (C) 2000-2013 The XCSoar Project
   6   A detailed list of copyright holders can be found in the file "AUTHORS".
   7
   8   This program is free software; you can redistribute it and/or
   9   modify it under the terms of the GNU General Public License
  10   as published by the Free Software Foundation; either version 2
  11   of the License, or (at your option) any later version.
  12
  13   This program is distributed in the hope that it will be useful,
  14   but WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16   GNU General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with this program; if not, write to the Free Software
  20   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  21 }
  22 */
  23
  24 #ifndef XCSOAR_CRC_HPP
  25 #define XCSOAR_CRC_HPP
  26
  27 #include "Compiler.h"
  28
  29 #include <stdint.h>
  30 #include <stddef.h>
  31
  32 extern const uint16_t crc16ccitt_table[256];
  33
  34 gcc_const
  35 static inline uint16_t
  36 UpdateCRC16CCITT(uint8_t octet, uint16_t crc)
  37 {
  38   return (crc << 8) ^ crc16ccitt_table[(crc >> 8) ^ octet];
  39 }
  40
  41 gcc_pure
  42 static inline uint16_t
  43 UpdateCRC16CCITT(const uint8_t *data, const uint8_t *end, uint16_t crc)
  44 {
  45   while (data < end)
  46     crc = UpdateCRC16CCITT(*data++, crc);
  47   return crc;
  48 }
  49
  50 gcc_pure
  51 static inline uint16_t
  52 UpdateCRC16CCITT(const void *data, size_t length, uint16_t crc)
  53 {
  54   const uint8_t *p = (const uint8_t *)data, *end = p + length;
  55   return UpdateCRC16CCITT(p, end, crc);
  56 }
  57
  58 #endif