3.13

7zip/Common/LSBFEncoder.cpp

@@ -0,0 +1,46 @@
+// LSBFEncoder.cpp
+
+#include "StdAfx.h"
+
+#include "LSBFEncoder.h"
+#include "Common/Defs.h"
+
+namespace NStream {
+namespace NLSBF {
+
+void CEncoder::WriteBits(UINT32 aValue, UINT32 aNumBits)
+{
+  while(aNumBits > 0)
+  {
+    UINT32 aNumNewBits = MyMin(aNumBits, m_BitPos);
+    aNumBits -= aNumNewBits;
+
+    UINT32 aMask = (1 << aNumNewBits) - 1;
+    m_CurByte |= (aValue & aMask) << (8 - m_BitPos);
+    aValue >>= aNumNewBits;
+
+    m_BitPos -= aNumNewBits;
+
+    if (m_BitPos == 0)
+    {
+      m_Stream.WriteByte(m_CurByte);
+      m_BitPos = 8;
+      m_CurByte = 0;
+    }
+  }
+}
+
+
+void CReverseEncoder::WriteBits(UINT32 aValue, UINT32 aNumBits)
+{
+  UINT32 aReverseValue = 0;
+  for(UINT32 i = 0; i < aNumBits; i++) 
+  {
+    aReverseValue <<= 1;
+    aReverseValue |= aValue & 1;
+    aValue >>= 1;
+  } 
+  m_Encoder->WriteBits(aReverseValue, aNumBits);
+}
+
+}}