SDL

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/*
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  Simple DirectMedia Layer
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  Copyright (C) 1997-2024 Sam Lantinga <slouken@libsdl.org>
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  This software is provided 'as-is', without any express or implied
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  warranty.  In no event will the authors be held liable for any damages
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  arising from the use of this software.
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  Permission is granted to anyone to use this software for any purpose,
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  including commercial applications, and to alter it and redistribute it
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  freely, subject to the following restrictions:
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  1. The origin of this software must not be misrepresented; you must not
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     claim that you wrote the original software. If you use this software
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     in a product, an acknowledgment in the product documentation would be
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     appreciated but is not required.
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  2. Altered source versions must be plainly marked as such, and must not be
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     misrepresented as being the original software.
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  3. This notice may not be removed or altered from any source distribution.
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*/
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/*
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 Used by the test execution component.
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 Original source code contributed by A. Schiffler for GSOC project.
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*/
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#include <SDL3/SDL_test.h>
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int SDLTest_Crc32Init(SDLTest_Crc32Context *crcContext)
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{
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    int i, j;
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    CrcUint32 c;
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    /* Sanity check context pointer */
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    if (!crcContext) {
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        return -1;
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    }
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    /*
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     * Build auxiliary table for parallel byte-at-a-time CRC-32
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     */
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#ifdef ORIGINAL_METHOD
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    for (i = 0; i < 256; ++i) {
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        for (c = i << 24, j = 8; j > 0; --j) {
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            c = c & 0x80000000 ? (c << 1) ^ CRC32_POLY : (c << 1);
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        }
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        crcContext->crc32_table[i] = c;
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    }
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#else
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    for (i = 0; i < 256; i++) {
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        c = i;
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        for (j = 8; j > 0; j--) {
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            if (c & 1) {
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                c = (c >> 1) ^ CRC32_POLY;
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            } else {
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                c >>= 1;
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            }
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        }
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        crcContext->crc32_table[i] = c;
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    }
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#endif
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    return 0;
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}
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/* Complete CRC32 calculation on a memory block */
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int SDLTest_Crc32Calc(SDLTest_Crc32Context *crcContext, CrcUint8 *inBuf, CrcUint32 inLen, CrcUint32 *crc32)
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{
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    if (SDLTest_Crc32CalcStart(crcContext, crc32)) {
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        return -1;
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    }
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    if (SDLTest_Crc32CalcBuffer(crcContext, inBuf, inLen, crc32)) {
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        return -1;
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    }
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    if (SDLTest_Crc32CalcEnd(crcContext, crc32)) {
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        return -1;
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    }
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    return 0;
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}
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/* Start crc calculation */
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int SDLTest_Crc32CalcStart(SDLTest_Crc32Context *crcContext, CrcUint32 *crc32)
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{
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    /* Sanity check pointers */
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    if (!crcContext) {
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        *crc32 = 0;
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        return -1;
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    }
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    /*
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     * Preload shift register, per CRC-32 spec
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     */
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    *crc32 = 0xffffffff;
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    return 0;
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}
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/* Finish crc calculation */
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int SDLTest_Crc32CalcEnd(SDLTest_Crc32Context *crcContext, CrcUint32 *crc32)
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{
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    /* Sanity check pointers */
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    if (!crcContext) {
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        *crc32 = 0;
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        return -1;
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    }
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    /*
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     * Return complement, per CRC-32 spec
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     */
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    *crc32 = (~(*crc32));
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    return 0;
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}
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/* Include memory block in crc */
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int SDLTest_Crc32CalcBuffer(SDLTest_Crc32Context *crcContext, CrcUint8 *inBuf, CrcUint32 inLen, CrcUint32 *crc32)
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{
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    CrcUint8 *p;
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    register CrcUint32 crc;
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    if (!crcContext) {
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        *crc32 = 0;
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        return -1;
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    }
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    if (!inBuf) {
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        return -1;
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    }
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    /*
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     * Calculate CRC from data
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     */
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    crc = *crc32;
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    for (p = inBuf; inLen > 0; ++p, --inLen) {
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#ifdef ORIGINAL_METHOD
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        crc = (crc << 8) ^ crcContext->crc32_table[(crc >> 24) ^ *p];
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#else
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        crc = ((crc >> 8) & 0x00FFFFFF) ^ crcContext->crc32_table[(crc ^ *p) & 0xFF];
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#endif
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    }
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    *crc32 = crc;
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    return 0;
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}
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int SDLTest_Crc32Done(SDLTest_Crc32Context *crcContext)
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{
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    if (!crcContext) {
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        return -1;
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    }
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    return 0;
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}
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