1 files changed, 56 insertions, 0 deletions
diff --git a/hostTools/lzma/decompress/RangeCoder.h b/hostTools/lzma/decompress/RangeCoder.h
new file mode 100644
index 0000000..ae6f974
--- /dev/null
+++ b/hostTools/lzma/decompress/RangeCoder.h
@@ -0,0 +1,56 @@
+#ifndef __COMPRESSION_RANGECODER_H
+#define __COMPRESSION_RANGECODER_H
+
+#include "IInOutStreams.h"
+
+#define kNumTopBits 24
+#define kTopValue (1 << kNumTopBits)
+
+typedef struct CRangeDecoder
+{
+  UINT32  m_Range;
+  UINT32  m_Code;
+} CRangeDecoder;
+
+
+
+INLINE void RangeDecoderInit(
+    ISequentialInStream *in_stream, 
+    CRangeDecoder *rangeDecoder)
+  {
+    int i;
+    rangeDecoder->m_Code = 0;
+    rangeDecoder->m_Range = (UINT32)(-1);
+    for(i = 0; i < 5; i++)
+      rangeDecoder->m_Code = (rangeDecoder->m_Code << 8) | InStreamReadByte(in_stream);
+  }
+
+INLINE UINT32 RangeDecodeDirectBits(
+    ISequentialInStream *in_stream, 
+    CRangeDecoder *rangeDecoder, 
+    UINT32 aNumTotalBits)
+  {
+    UINT32 aRange = rangeDecoder->m_Range;
+    UINT32 aCode = rangeDecoder->m_Code;        
+    UINT32 aResult = 0;
+    UINT32 i;
+    for (i = aNumTotalBits; i > 0; i--)
+    {
+      UINT32 t;
+      aRange >>= 1;
+      t = (aCode - aRange) >> 31;
+      aCode -= aRange & (t - 1);
+      aResult = (aResult << 1) | (1 - t);
+
+      if (aRange < kTopValue)
+      {
+        aCode = (aCode << 8) | InStreamReadByte(in_stream);
+        aRange <<= 8; 
+      }
+    }
+    rangeDecoder->m_Range = aRange;
+    rangeDecoder->m_Code = aCode;
+    return aResult;
+  }
+
+#endif