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