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// LzhCRC.cpp
#include "StdAfx.h"
#include "LzhCRC.h"
namespace NArchive {
namespace NLzh {
static const UInt16 kCRCPoly = 0xA001;
UInt16 CCRC::Table[256];
void CCRC::InitTable()
{
for (UInt32 i = 0; i < 256; i++)
{
UInt32 r = i;
for (int j = 0; j < 8; j++)
if (r & 1)
r = (r >> 1) ^ kCRCPoly;
else
r >>= 1;
CCRC::Table[i] = (UInt16)r;
}
}
class CCRCTableInit
{
public:
CCRCTableInit() { CCRC::InitTable(); }
} g_CRCTableInit;
void CCRC::Update(const void *data, size_t size)
{
UInt16 v = _value;
const Byte *p = (const Byte *)data;
for (; size > 0; size--, p++)
v = (UInt16)(Table[((Byte)(v)) ^ *p] ^ (v >> 8));
_value = v;
}
}}
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