Initialer Commit

CPP/7zip/Compress/BitmEncoder.h

@@ -0,0 +1,49 @@
+// BitmEncoder.h -- the Most Significant Bit of byte is First
+
+#ifndef __BITM_ENCODER_H
+#define __BITM_ENCODER_H
+
+#include "../IStream.h"
+
+template<class TOutByte>
+class CBitmEncoder
+{
+  unsigned _bitPos;
+  Byte _curByte;
+  TOutByte _stream;
+public:
+  bool Create(UInt32 bufferSize) { return _stream.Create(bufferSize); }
+  void SetStream(ISequentialOutStream *outStream) { _stream.SetStream(outStream);}
+  UInt64 GetProcessedSize() const { return _stream.GetProcessedSize() + ((8 - _bitPos + 7) >> 3); }
+  void Init()
+  {
+    _stream.Init();
+    _bitPos = 8;
+    _curByte = 0;
+  }
+  HRESULT Flush()
+  {
+    if (_bitPos < 8)
+      WriteBits(0, _bitPos);
+    return _stream.Flush();
+  }
+  void WriteBits(UInt32 value, unsigned numBits)
+  {
+    while (numBits > 0)
+    {
+      if (numBits < _bitPos)
+      {
+        _curByte |= ((Byte)value << (_bitPos -= numBits));
+        return;
+      }
+      numBits -= _bitPos;
+      UInt32 newBits = (value >> numBits);
+      value -= (newBits << numBits);
+      _stream.WriteByte((Byte)(_curByte | newBits));
+      _bitPos = 8;
+      _curByte = 0;
+    }
+  }
+};
+
+#endif