ec6957f356
- upgraded to the latest LZMA SDK git-svn-id: https://svn.code.sf.net/p/nsis/code/NSIS/trunk@3637 212acab6-be3b-0410-9dea-997c60f758d6
55 lines
938 B
C++
55 lines
938 B
C++
// Common/CRC.cpp
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#include "StdAfx.h"
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#include "CRC.h"
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static const UInt32 kCRCPoly = 0xEDB88320;
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UInt32 CCRC::Table[256];
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void CCRC::InitTable()
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{
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for (UInt32 i = 0; i < 256; i++)
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{
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UInt32 r = i;
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for (int j = 0; j < 8; j++)
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if (r & 1)
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r = (r >> 1) ^ kCRCPoly;
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else
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r >>= 1;
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CCRC::Table[i] = r;
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}
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}
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class CCRCTableInit
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{
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public:
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CCRCTableInit() { CCRC::InitTable(); }
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} g_CRCTableInit;
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void CCRC::Update(Byte b)
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{
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_value = Table[((Byte)(_value)) ^ b] ^ (_value >> 8);
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}
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void CCRC::Update(UInt32 v)
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{
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for (int i = 0; i < 4; i++)
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Update((Byte)(v >> (8 * i)));
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}
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void CCRC::Update(const UInt64 &v)
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{
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for (int i = 0; i < 8; i++)
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Update((Byte)(v >> (8 * i)));
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}
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void CCRC::Update(const void *data, UInt32 size)
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{
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UInt32 v = _value;
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const Byte *p = (const Byte *)data;
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for (; size > 0 ; size--, p++)
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v = Table[((Byte)(v)) ^ *p] ^ (v >> 8);
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_value = v;
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}
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