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-rwxr-xr-xCPP/7zip/Compress/RangeCoder.h205
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diff --git a/CPP/7zip/Compress/RangeCoder.h b/CPP/7zip/Compress/RangeCoder.h
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+++ b/CPP/7zip/Compress/RangeCoder.h
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+// Compress/RangeCoder.h
+// 2009-05-30 : Igor Pavlov : Public domain
+
+#ifndef __COMPRESS_RANGE_CODER_H
+#define __COMPRESS_RANGE_CODER_H
+
+#include "../Common/InBuffer.h"
+#include "../Common/OutBuffer.h"
+
+namespace NCompress {
+namespace NRangeCoder {
+
+const int kNumTopBits = 24;
+const UInt32 kTopValue = (1 << kNumTopBits);
+
+class CEncoder
+{
+ UInt32 _cacheSize;
+ Byte _cache;
+public:
+ UInt64 Low;
+ UInt32 Range;
+ COutBuffer Stream;
+ bool Create(UInt32 bufferSize) { return Stream.Create(bufferSize); }
+
+ void SetStream(ISequentialOutStream *stream) { Stream.SetStream(stream); }
+ void Init()
+ {
+ Stream.Init();
+ Low = 0;
+ Range = 0xFFFFFFFF;
+ _cacheSize = 1;
+ _cache = 0;
+ }
+
+ void FlushData()
+ {
+ // Low += 1;
+ for(int i = 0; i < 5; i++)
+ ShiftLow();
+ }
+
+ HRESULT FlushStream() { return Stream.Flush(); }
+
+ void ReleaseStream() { Stream.ReleaseStream(); }
+
+ void Encode(UInt32 start, UInt32 size, UInt32 total)
+ {
+ Low += start * (Range /= total);
+ Range *= size;
+ while (Range < kTopValue)
+ {
+ Range <<= 8;
+ ShiftLow();
+ }
+ }
+
+ void ShiftLow()
+ {
+ if ((UInt32)Low < (UInt32)0xFF000000 || (int)(Low >> 32) != 0)
+ {
+ Byte temp = _cache;
+ do
+ {
+ Stream.WriteByte((Byte)(temp + (Byte)(Low >> 32)));
+ temp = 0xFF;
+ }
+ while(--_cacheSize != 0);
+ _cache = (Byte)((UInt32)Low >> 24);
+ }
+ _cacheSize++;
+ Low = (UInt32)Low << 8;
+ }
+
+ void EncodeDirectBits(UInt32 value, int numBits)
+ {
+ for (numBits--; numBits >= 0; numBits--)
+ {
+ Range >>= 1;
+ Low += Range & (0 - ((value >> numBits) & 1));
+ if (Range < kTopValue)
+ {
+ Range <<= 8;
+ ShiftLow();
+ }
+ }
+ }
+
+ void EncodeBit(UInt32 size0, UInt32 numTotalBits, UInt32 symbol)
+ {
+ UInt32 newBound = (Range >> numTotalBits) * size0;
+ if (symbol == 0)
+ Range = newBound;
+ else
+ {
+ Low += newBound;
+ Range -= newBound;
+ }
+ while (Range < kTopValue)
+ {
+ Range <<= 8;
+ ShiftLow();
+ }
+ }
+
+ UInt64 GetProcessedSize() { return Stream.GetProcessedSize() + _cacheSize + 4; }
+};
+
+class CDecoder
+{
+public:
+ CInBuffer Stream;
+ UInt32 Range;
+ UInt32 Code;
+ bool Create(UInt32 bufferSize) { return Stream.Create(bufferSize); }
+
+ void Normalize()
+ {
+ while (Range < kTopValue)
+ {
+ Code = (Code << 8) | Stream.ReadByte();
+ Range <<= 8;
+ }
+ }
+
+ void SetStream(ISequentialInStream *stream) { Stream.SetStream(stream); }
+ void Init()
+ {
+ Stream.Init();
+ Code = 0;
+ Range = 0xFFFFFFFF;
+ for(int i = 0; i < 5; i++)
+ Code = (Code << 8) | Stream.ReadByte();
+ }
+
+ void ReleaseStream() { Stream.ReleaseStream(); }
+
+ UInt32 GetThreshold(UInt32 total)
+ {
+ return (Code) / ( Range /= total);
+ }
+
+ void Decode(UInt32 start, UInt32 size)
+ {
+ Code -= start * Range;
+ Range *= size;
+ Normalize();
+ }
+
+ UInt32 DecodeDirectBits(int numTotalBits)
+ {
+ UInt32 range = Range;
+ UInt32 code = Code;
+ UInt32 result = 0;
+ for (int i = numTotalBits; i != 0; i--)
+ {
+ range >>= 1;
+ /*
+ result <<= 1;
+ if (code >= range)
+ {
+ code -= range;
+ result |= 1;
+ }
+ */
+ UInt32 t = (code - range) >> 31;
+ code -= range & (t - 1);
+ result = (result << 1) | (1 - t);
+
+ if (range < kTopValue)
+ {
+ code = (code << 8) | Stream.ReadByte();
+ range <<= 8;
+ }
+ }
+ Range = range;
+ Code = code;
+ return result;
+ }
+
+ UInt32 DecodeBit(UInt32 size0, UInt32 numTotalBits)
+ {
+ UInt32 newBound = (Range >> numTotalBits) * size0;
+ UInt32 symbol;
+ if (Code < newBound)
+ {
+ symbol = 0;
+ Range = newBound;
+ }
+ else
+ {
+ symbol = 1;
+ Code -= newBound;
+ Range -= newBound;
+ }
+ Normalize();
+ return symbol;
+ }
+
+ UInt64 GetProcessedSize() {return Stream.GetProcessedSize(); }
+};
+
+}}
+
+#endif