mirror of
https://github.com/Relintai/sdl2_frt.git
synced 2024-12-25 09:17:12 +01:00
167 lines
3.4 KiB
C
167 lines
3.4 KiB
C
/*
|
|
Simple DirectMedia Layer
|
|
Copyright (C) 1997-2020 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: */
|