21.04

CPP/Common/CksumReg.cpp

@@ -0,0 +1,60 @@
+// CksumReg.cpp
+
+#include "StdAfx.h"
+
+#include "../../C/CpuArch.h"
+
+#include "../Common/MyCom.h"
+
+#include "../7zip/Common/RegisterCodec.h"
+
+#include "../7zip/Compress/BZip2Crc.h"
+
+class CCksumHasher:
+  public IHasher,
+  public CMyUnknownImp
+{
+  CBZip2Crc _crc;
+  UInt64 _size;
+  Byte mtDummy[1 << 7];
+  
+public:
+  CCksumHasher()
+  {
+    _crc.Init(0);
+    _size = 0;
+  }
+
+  MY_UNKNOWN_IMP1(IHasher)
+  INTERFACE_IHasher(;)
+};
+
+STDMETHODIMP_(void) CCksumHasher::Init() throw()
+{
+  _crc.Init(0);
+  _size = 0;
+}
+
+STDMETHODIMP_(void) CCksumHasher::Update(const void *data, UInt32 size) throw()
+{
+  _size += size;
+  CBZip2Crc crc = _crc;
+  for (UInt32 i = 0; i < size; i++)
+    crc.UpdateByte(((const Byte *)data)[i]);
+  _crc = crc;
+}
+
+STDMETHODIMP_(void) CCksumHasher::Final(Byte *digest) throw()
+{
+  UInt64 size = _size;
+  CBZip2Crc crc = _crc;
+  while (size)
+  {
+    crc.UpdateByte((Byte)size);
+    size >>= 8;
+  }
+  const UInt32 val = crc.GetDigest();
+  SetUi32(digest, val);
+}
+
+REGISTER_HASHER(CCksumHasher, 0x203, "CKSUM", 4)