kc3-lang/SDL/src/stdlib/SDL_crc16.c

• Show log

  Commit

• Hash : b8d85c69
  Author :
  Date : 2022-11-30T12:51:59
  

  Update for SDL3 coding style (#6717) I updated .clang-format and ran clang-format 14 over the src and test directories to standardize the code base. In general I let clang-format have it's way, and added markup to prevent formatting of code that would break or be completely unreadable if formatted. The script I ran for the src directory is added as build-scripts/clang-format-src.sh This fixes: #6592 #6593 #6594 (cherry picked from commit 5750bcb174300011b91d1de20edb288fcca70f8c)

Download

• src/stdlib/SDL_crc16.c

• /*
    Simple DirectMedia Layer
    Copyright (C) 1997-2022 Sam Lantinga <slouken@libsdl.org>
  
    This software is provided 'as-is', without any express or implied
    warranty.  In no event will the authors be held liable for any damages
    arising from the use of this software.
  
    Permission is granted to anyone to use this software for any purpose,
    including commercial applications, and to alter it and redistribute it
    freely, subject to the following restrictions:
  
    1. The origin of this software must not be misrepresented; you must not
       claim that you wrote the original software. If you use this software
       in a product, an acknowledgment in the product documentation would be
       appreciated but is not required.
    2. Altered source versions must be plainly marked as such, and must not be
       misrepresented as being the original software.
    3. This notice may not be removed or altered from any source distribution.
  */
  #include "../SDL_internal.h"
  
  #include "SDL_stdinc.h"
  
  
  /* Public domain CRC implementation adapted from:
     http://home.thep.lu.se/~bjorn/crc/crc32_simple.c
  
     This algorithm is compatible with the 16-bit CRC described here:
     https://www.lammertbies.nl/comm/info/crc-calculation
  */
  /* NOTE: DO NOT CHANGE THIS ALGORITHM
     There is code that relies on this in the joystick code
  */
  
  static Uint16 crc16_for_byte(Uint8 r)
  {
      Uint16 crc = 0;
      int i;
      for (i = 0; i < 8; ++i) {
          crc = ((crc ^ r) & 1 ? 0xA001 : 0) ^ crc >> 1;
          r >>= 1;
      }
      return crc;
  }
  
  Uint16 SDL_crc16(Uint16 crc, const void *data, size_t len)
  {
      /* As an optimization we can precalculate a 256 entry table for each byte */
      size_t i;
      for (i = 0; i < len; ++i) {
          crc = crc16_for_byte((Uint8)crc ^ ((const Uint8 *)data)[i]) ^ crc >> 8;
      }
      return crc;
  }
  
  /* vi: set ts=4 sw=4 expandtab: */
  

Download