Mercurial > vba-linux
comparison src/win32/7zip/7z/CPP/7zip/Archive/Lzh/LzhCRC.cpp @ 1:f9f4f1b99eed
importing src directory
author | Robert McIntyre <rlm@mit.edu> |
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date | Sat, 03 Mar 2012 10:31:27 -0600 |
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0:8ced16adf2e1 | 1:f9f4f1b99eed |
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1 // LzhCRC.cpp | |
2 | |
3 #include "StdAfx.h" | |
4 | |
5 #include "LzhCRC.h" | |
6 | |
7 namespace NArchive { | |
8 namespace NLzh { | |
9 | |
10 static const UInt16 kCRCPoly = 0xA001; | |
11 | |
12 UInt16 CCRC::Table[256]; | |
13 | |
14 void CCRC::InitTable() | |
15 { | |
16 for (UInt32 i = 0; i < 256; i++) | |
17 { | |
18 UInt32 r = i; | |
19 for (int j = 0; j < 8; j++) | |
20 if (r & 1) | |
21 r = (r >> 1) ^ kCRCPoly; | |
22 else | |
23 r >>= 1; | |
24 CCRC::Table[i] = (UInt16)r; | |
25 } | |
26 } | |
27 | |
28 class CCRCTableInit | |
29 { | |
30 public: | |
31 CCRCTableInit() { CCRC::InitTable(); } | |
32 } g_CRCTableInit; | |
33 | |
34 void CCRC::Update(const void *data, size_t size) | |
35 { | |
36 UInt16 v = _value; | |
37 const Byte *p = (const Byte *)data; | |
38 for (; size > 0; size--, p++) | |
39 v = (UInt16)(Table[((Byte)(v)) ^ *p] ^ (v >> 8)); | |
40 _value = v; | |
41 } | |
42 | |
43 }} |