110 lines
2.6 KiB
C++
110 lines
2.6 KiB
C++
/***************************************************************************
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* *
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* Project64-video - A Nintendo 64 gfx plugin. *
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* http://www.pj64-emu.com/ *
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* Copyright (C) 2017 Project64. All rights reserved. *
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* Copyright (C) 2003-2009 Sergey 'Gonetz' Lipski *
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* Copyright (C) 2002 Dave2001 *
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* *
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* License: *
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* GNU/GPLv2 http://www.gnu.org/licenses/gpl-2.0.html *
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* version 2 of the License, or (at your option) any later version. *
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* *
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****************************************************************************/
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#define CRC32_POLYNOMIAL 0x04C11DB7
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unsigned int CRCTable[256];
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unsigned int Reflect(unsigned int ref, char ch)
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{
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unsigned int value = 0;
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// Swap bit 0 for bit 7
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// bit 1 for bit 6, etc.
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for (char i = 1; i < (ch + 1); i++)
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{
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if (ref & 1)
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value |= 1 << (ch - i);
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ref >>= 1;
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}
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return value;
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}
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void CRC_BuildTable()
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{
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unsigned int crc;
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for (unsigned i = 0; i <= 255; i++)
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{
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crc = Reflect(i, 8) << 24;
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for (unsigned j = 0; j < 8; j++)
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crc = (crc << 1) ^ (crc & (1 << 31) ? CRC32_POLYNOMIAL : 0);
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CRCTable[i] = Reflect(crc, 32);
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}
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}
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//*/
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//*
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unsigned int CRC32(unsigned int crc, void *buffer, unsigned int count)
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{
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unsigned int orig = crc;
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unsigned char * p = reinterpret_cast<unsigned char*>(buffer);
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while (count--)
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crc = (crc >> 8) ^ CRCTable[(crc & 0xFF) ^ *p++];
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return crc ^ orig;
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}
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//*/
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/*
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uint32_t CRC_Calculate( uint32_t crc, void *buffer, uint32_t count )
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{
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uint32_t Crc32=crc;
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__asm {
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mov esi, buffer
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mov ecx, count
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mov edx, crc
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xor eax, eax
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loop1:
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inc esi
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mov al, dl
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xor al, byte ptr [esi]
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shr edx, 8
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mov ebx, [CRCTable+eax*4]
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xor edx, ebx
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loop loop1
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xor Crc32, edx
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}
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return Crc32;
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}
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*/
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/*
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unsigned int CRC_Calculate( unsigned int crc, void *buffer, unsigned int count )
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{
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unsigned int Crc32=crc;
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__asm {
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mov esi, buffer
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mov edx, count
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add edx, esi
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mov ecx, crc
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loop1:
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mov bl, byte ptr [esi]
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movzx eax, cl
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inc esi
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xor al, bl
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shr ecx, 8
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mov ebx, [CRCTable+eax*4]
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xor ecx, ebx
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cmp edx, esi
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jne loop1
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xor Crc32, ecx
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}
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return Crc32;
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}
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//*/ |