| /* |
| Simple DirectMedia Layer |
| Copyright (C) 1997-2023 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. |
| */ |
| |
| /* |
| |
| Used by the test execution component. |
| Original source code contributed by A. Schiffler for GSOC project. |
| |
| */ |
| |
| #include "SDL_config.h" |
| |
| #include "SDL_test.h" |
| |
| int SDLTest_Crc32Init(SDLTest_Crc32Context *crcContext) |
| { |
| int i, j; |
| CrcUint32 c; |
| |
| /* Sanity check context pointer */ |
| if (crcContext == NULL) { |
| return -1; |
| } |
| |
| /* |
| * Build auxiliary table for parallel byte-at-a-time CRC-32 |
| */ |
| #ifdef ORIGINAL_METHOD |
| for (i = 0; i < 256; ++i) { |
| for (c = i << 24, j = 8; j > 0; --j) { |
| c = c & 0x80000000 ? (c << 1) ^ CRC32_POLY : (c << 1); |
| } |
| crcContext->crc32_table[i] = c; |
| } |
| #else |
| for (i = 0; i < 256; i++) { |
| c = i; |
| for (j = 8; j > 0; j--) { |
| if (c & 1) { |
| c = (c >> 1) ^ CRC32_POLY; |
| } else { |
| c >>= 1; |
| } |
| } |
| crcContext->crc32_table[i] = c; |
| } |
| #endif |
| |
| return 0; |
| } |
| |
| /* Complete CRC32 calculation on a memory block */ |
| int SDLTest_Crc32Calc(SDLTest_Crc32Context *crcContext, CrcUint8 *inBuf, CrcUint32 inLen, CrcUint32 *crc32) |
| { |
| if (SDLTest_Crc32CalcStart(crcContext, crc32)) { |
| return -1; |
| } |
| |
| if (SDLTest_Crc32CalcBuffer(crcContext, inBuf, inLen, crc32)) { |
| return -1; |
| } |
| |
| if (SDLTest_Crc32CalcEnd(crcContext, crc32)) { |
| return -1; |
| } |
| |
| return 0; |
| } |
| |
| /* Start crc calculation */ |
| |
| int SDLTest_Crc32CalcStart(SDLTest_Crc32Context *crcContext, CrcUint32 *crc32) |
| { |
| /* Sanity check pointers */ |
| if (crcContext == NULL) { |
| *crc32 = 0; |
| return -1; |
| } |
| |
| /* |
| * Preload shift register, per CRC-32 spec |
| */ |
| *crc32 = 0xffffffff; |
| |
| return 0; |
| } |
| |
| /* Finish crc calculation */ |
| |
| int SDLTest_Crc32CalcEnd(SDLTest_Crc32Context *crcContext, CrcUint32 *crc32) |
| { |
| /* Sanity check pointers */ |
| if (crcContext == NULL) { |
| *crc32 = 0; |
| return -1; |
| } |
| |
| /* |
| * Return complement, per CRC-32 spec |
| */ |
| *crc32 = (~(*crc32)); |
| |
| return 0; |
| } |
| |
| /* Include memory block in crc */ |
| |
| int SDLTest_Crc32CalcBuffer(SDLTest_Crc32Context *crcContext, CrcUint8 *inBuf, CrcUint32 inLen, CrcUint32 *crc32) |
| { |
| CrcUint8 *p; |
| register CrcUint32 crc; |
| |
| if (crcContext == NULL) { |
| *crc32 = 0; |
| return -1; |
| } |
| |
| if (inBuf == NULL) { |
| return -1; |
| } |
| |
| /* |
| * Calculate CRC from data |
| */ |
| crc = *crc32; |
| for (p = inBuf; inLen > 0; ++p, --inLen) { |
| #ifdef ORIGINAL_METHOD |
| crc = (crc << 8) ^ crcContext->crc32_table[(crc >> 24) ^ *p]; |
| #else |
| crc = ((crc >> 8) & 0x00FFFFFF) ^ crcContext->crc32_table[(crc ^ *p) & 0xFF]; |
| #endif |
| } |
| *crc32 = crc; |
| |
| return 0; |
| } |
| |
| int SDLTest_Crc32Done(SDLTest_Crc32Context *crcContext) |
| { |
| if (crcContext == NULL) { |
| return -1; |
| } |
| |
| return 0; |
| } |
| |
| /* vi: set ts=4 sw=4 expandtab: */ |