src/test/SDL_test_crc32.c
author Ryan C. Gordon <icculus@icculus.org>
Sun, 21 Oct 2018 22:40:17 -0400
changeset 12345 50e1cca28b39
parent 11811 5d94cb6b24d3
child 12503 806492103856
permissions -rw-r--r--
wasapi/win32: Sort initial device lists by device GUID.

This makes an unchanged set of hardware always report devices in the same
order on each run.
     1 /*
     2   Simple DirectMedia Layer
     3   Copyright (C) 1997-2018 Sam Lantinga <slouken@libsdl.org>
     4 
     5   This software is provided 'as-is', without any express or implied
     6   warranty.  In no event will the authors be held liable for any damages
     7   arising from the use of this software.
     8 
     9   Permission is granted to anyone to use this software for any purpose,
    10   including commercial applications, and to alter it and redistribute it
    11   freely, subject to the following restrictions:
    12 
    13   1. The origin of this software must not be misrepresented; you must not
    14      claim that you wrote the original software. If you use this software
    15      in a product, an acknowledgment in the product documentation would be
    16      appreciated but is not required.
    17   2. Altered source versions must be plainly marked as such, and must not be
    18      misrepresented as being the original software.
    19   3. This notice may not be removed or altered from any source distribution.
    20 */
    21 
    22 /*
    23 
    24  Used by the test execution component.
    25  Original source code contributed by A. Schiffler for GSOC project.
    26 
    27 */
    28 
    29 #include "SDL_config.h"
    30 
    31 #include "SDL_test.h"
    32 
    33 
    34 int SDLTest_Crc32Init(SDLTest_Crc32Context *crcContext)
    35 {
    36   int i,j;
    37   CrcUint32 c;
    38 
    39   /* Sanity check context pointer */
    40   if (crcContext==NULL) {
    41    return -1;
    42   }
    43 
    44   /*
    45    * Build auxiliary table for parallel byte-at-a-time CRC-32
    46    */
    47 #ifdef ORIGINAL_METHOD
    48   for (i = 0; i < 256; ++i) {
    49     for (c = i << 24, j = 8; j > 0; --j) {
    50       c = c & 0x80000000 ? (c << 1) ^ CRC32_POLY : (c << 1);
    51     }
    52     crcContext->crc32_table[i] = c;
    53   }
    54 #else
    55   for (i=0; i<256; i++) {
    56    c = i;
    57    for (j=8; j>0; j--) {
    58     if (c & 1) {
    59      c = (c >> 1) ^ CRC32_POLY;
    60     } else {
    61      c >>= 1;
    62     }
    63    }
    64    crcContext->crc32_table[i] = c;
    65   }
    66 #endif
    67 
    68   return 0;
    69 }
    70 
    71 /* Complete CRC32 calculation on a memory block */
    72 int SDLTest_Crc32Calc(SDLTest_Crc32Context * crcContext, CrcUint8 *inBuf, CrcUint32 inLen, CrcUint32 *crc32)
    73 {
    74   if (SDLTest_Crc32CalcStart(crcContext,crc32)) {
    75    return -1;
    76   }
    77 
    78   if (SDLTest_Crc32CalcBuffer(crcContext, inBuf, inLen, crc32)) {
    79    return -1;
    80   }
    81 
    82   if (SDLTest_Crc32CalcEnd(crcContext, crc32)) {
    83    return -1;
    84   }
    85 
    86   return 0;
    87 }
    88 
    89 /* Start crc calculation */
    90 
    91 int SDLTest_Crc32CalcStart(SDLTest_Crc32Context * crcContext, CrcUint32 *crc32)
    92 {
    93   /* Sanity check pointers */
    94   if (crcContext==NULL) {
    95    *crc32=0;
    96    return -1;
    97   }
    98 
    99   /*
   100    * Preload shift register, per CRC-32 spec
   101    */
   102   *crc32 = 0xffffffff;
   103 
   104   return 0;
   105 }
   106 
   107 /* Finish crc calculation */
   108 
   109 int SDLTest_Crc32CalcEnd(SDLTest_Crc32Context * crcContext, CrcUint32 *crc32)
   110 {
   111   /* Sanity check pointers */
   112   if (crcContext==NULL) {
   113    *crc32=0;
   114    return -1;
   115   }
   116 
   117   /*
   118    * Return complement, per CRC-32 spec
   119    */
   120   *crc32 = (~(*crc32));
   121 
   122   return 0;
   123 }
   124 
   125 /* Include memory block in crc */
   126 
   127 int SDLTest_Crc32CalcBuffer(SDLTest_Crc32Context * crcContext, CrcUint8 *inBuf, CrcUint32 inLen, CrcUint32 *crc32)
   128 {
   129   CrcUint8    *p;
   130   register CrcUint32    crc;
   131 
   132   if (crcContext==NULL) {
   133    *crc32=0;
   134    return -1;
   135   }
   136 
   137   if (inBuf==NULL) {
   138    return -1;
   139   }
   140 
   141   /*
   142    * Calculate CRC from data
   143    */
   144   crc = *crc32;
   145   for (p = inBuf; inLen > 0; ++p, --inLen) {
   146 #ifdef ORIGINAL_METHOD
   147     crc = (crc << 8) ^ crcContext->crc32_table[(crc >> 24) ^ *p];
   148 #else
   149     crc = ((crc >> 8) & 0x00FFFFFF) ^ crcContext->crc32_table[ (crc ^ *p) & 0xFF ];
   150 #endif
   151   }
   152   *crc32 = crc;
   153 
   154   return 0;
   155 }
   156 
   157 int SDLTest_Crc32Done(SDLTest_Crc32Context * crcContext)
   158 {
   159   if (crcContext==NULL) {
   160      return -1;
   161   }
   162 
   163   return 0;
   164 }
   165 
   166 /* vi: set ts=4 sw=4 expandtab: */