mirror of
https://github.com/blawar/GLideN64.git
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63 lines
1.1 KiB
C++
63 lines
1.1 KiB
C++
#include "CRC.h"
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#define XXH_INLINE_ALL
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#include "xxHash/xxhash.h"
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#define CRC32_POLYNOMIAL 0x04C11DB7
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unsigned int CRCTable[ 256 ];
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static
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u32 Reflect( u32 ref, char ch )
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{
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u32 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 (int i = 1; i < (ch + 1); ++i) {
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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_Init()
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{
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u32 crc;
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for (int i = 0; i < 256; ++i) {
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crc = Reflect( i, 8 ) << 24;
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for (int 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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u32 CRC_Calculate_Strict( u32 crc, const void * buffer, u32 count )
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{
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u8 *p;
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u32 orig = crc;
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p = (u8*) 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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u64 CRC_Calculate( u64 crc, const void * buffer, u32 count )
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{
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return XXH3_64bits_withSeed(buffer, count, crc);
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}
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u64 CRC_CalculatePalette( u64 crc, const void * buffer, u32 count )
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{
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u8 *p = (u8*) buffer;
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while (count--) {
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crc = XXH3_64bits_withSeed(p, 2, crc);
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p += 8;
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}
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return crc;
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}
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