3.13

7zip/Common/MSBFEncoder.h

@@ -0,0 +1,70 @@
+// Stream/MSBFEncoder.h
+// the Most Significant Bit of byte is First
+
+#pragma once
+
+#ifndef __STREAM_MSBFENCODER_H
+#define __STREAM_MSBFENCODER_H
+
+#include "Common/Defs.h"
+#include "Interface/IInOutStreams.h"
+
+namespace NStream {
+namespace NMSBF {
+
+template<class TOutByte>
+class CEncoder
+{
+  TOutByte m_Stream;
+  UINT32 m_BitPos;
+  BYTE m_CurByte;
+public:
+  void Init(ISequentialOutStream *aStream)
+  {
+    m_Stream.Init(aStream);
+    m_BitPos = 8; 
+    m_CurByte = 0;
+  }
+  HRESULT Flush()
+  {
+    if(m_BitPos < 8)
+      WriteBits(0, m_BitPos);
+    return m_Stream.Flush();
+  }
+
+  void ReleaseStream()
+  {
+    m_Stream.ReleaseStream();
+  }
+
+  void WriteBits(UINT32 aValue, UINT32 aNumBits)
+  {
+    while(aNumBits > 0)
+    {
+      UINT32 aNumNewBits = MyMin(aNumBits, m_BitPos);
+      aNumBits -= aNumNewBits;
+      
+      
+      m_CurByte <<= aNumNewBits;
+      UINT32 aNewBits = aValue >> aNumBits;
+      m_CurByte |= BYTE(aNewBits);
+      aValue -= (aNewBits << aNumBits);
+      
+      
+      m_BitPos -= aNumNewBits;
+      
+      if (m_BitPos == 0)
+      {
+        m_Stream.WriteByte(m_CurByte);
+        m_BitPos = 8;
+      }
+    }
+  }
+  UINT64 GetProcessedSize() const { 
+      return m_Stream.GetProcessedSize() + (8 - m_BitPos + 7) /8; }
+};
+
+}}
+
+#endif
+