Keep only base/extractor.[cc|h].

third_party/lzma/v4_65/files/CS/7zip/Compress/RangeCoder/RangeCoderBitTree.cs

-using System;
-
-namespace SevenZip.Compression.RangeCoder
-{
-        struct BitTreeEncoder
-        {
-                BitEncoder[] Models;
-                int NumBitLevels;
-
-                public BitTreeEncoder(int numBitLevels)
-                {
-                        NumBitLevels = numBitLevels;
-                        Models = new BitEncoder[1 << numBitLevels];
-                }
-
-                public void Init()
-                {
-                        for (uint i = 1; i < (1 << NumBitLevels); i++)
-                                Models[i].Init();
-                }
-
-                public void Encode(Encoder rangeEncoder, UInt32 symbol)
-                {
-                        UInt32 m = 1;
-                        for (int bitIndex = NumBitLevels; bitIndex > 0; )
-                        {
-                                bitIndex--;
-                                UInt32 bit = (symbol >> bitIndex) & 1;
-                                Models[m].Encode(rangeEncoder, bit);
-                                m = (m << 1) | bit;
-                        }
-                }
-
-                public void ReverseEncode(Encoder rangeEncoder, UInt32 symbol)
-                {
-                        UInt32 m = 1;
-                        for (UInt32 i = 0; i < NumBitLevels; i++)
-                        {
-                                UInt32 bit = symbol & 1;
-                                Models[m].Encode(rangeEncoder, bit);
-                                m = (m << 1) | bit;
-                                symbol >>= 1;
-                        }
-                }
-
-                public UInt32 GetPrice(UInt32 symbol)
-                {
-                        UInt32 price = 0;
-                        UInt32 m = 1;
-                        for (int bitIndex = NumBitLevels; bitIndex > 0; )
-                        {
-                                bitIndex--;
-                                UInt32 bit = (symbol >> bitIndex) & 1;
-                                price += Models[m].GetPrice(bit);
-                                m = (m << 1) + bit;
-                        }
-                        return price;
-                }
-
-                public UInt32 ReverseGetPrice(UInt32 symbol)
-                {
-                        UInt32 price = 0;
-                        UInt32 m = 1;
-                        for (int i = NumBitLevels; i > 0; i--)
-                        {
-                                UInt32 bit = symbol & 1;
-                                symbol >>= 1;
-                                price += Models[m].GetPrice(bit);
-                                m = (m << 1) | bit;
-                        }
-                        return price;
-                }
-
-                public static UInt32 ReverseGetPrice(BitEncoder[] Models, UInt32 startIndex,
-                        int NumBitLevels, UInt32 symbol)
-                {
-                        UInt32 price = 0;
-                        UInt32 m = 1;
-                        for (int i = NumBitLevels; i > 0; i--)
-                        {
-                                UInt32 bit = symbol & 1;
-                                symbol >>= 1;
-                                price += Models[startIndex + m].GetPrice(bit);
-                                m = (m << 1) | bit;
-                        }
-                        return price;
-                }
-
-                public static void ReverseEncode(BitEncoder[] Models, UInt32 startIndex,
-                        Encoder rangeEncoder, int NumBitLevels, UInt32 symbol)
-                {
-                        UInt32 m = 1;
-                        for (int i = 0; i < NumBitLevels; i++)
-                        {
-                                UInt32 bit = symbol & 1;
-                                Models[startIndex + m].Encode(rangeEncoder, bit);
-                                m = (m << 1) | bit;
-                                symbol >>= 1;
-                        }
-                }
-        }
-
-        struct BitTreeDecoder
-        {
-                BitDecoder[] Models;
-                int NumBitLevels;
-
-                public BitTreeDecoder(int numBitLevels)
-                {
-                        NumBitLevels = numBitLevels;
-                        Models = new BitDecoder[1 << numBitLevels];
-                }
-
-                public void Init()
-                {
-                        for (uint i = 1; i < (1 << NumBitLevels); i++)
-                                Models[i].Init();
-                }
-
-                public uint Decode(RangeCoder.Decoder rangeDecoder)
-                {
-                        uint m = 1;
-                        for (int bitIndex = NumBitLevels; bitIndex > 0; bitIndex--)
-                                m = (m << 1) + Models[m].Decode(rangeDecoder);
-                        return m - ((uint)1 << NumBitLevels);
-                }
-
-                public uint ReverseDecode(RangeCoder.Decoder rangeDecoder)
-                {
-                        uint m = 1;
-                        uint symbol = 0;
-                        for (int bitIndex = 0; bitIndex < NumBitLevels; bitIndex++)
-                        {
-                                uint bit = Models[m].Decode(rangeDecoder);
-                                m <<= 1;
-                                m += bit;
-                                symbol |= (bit << bitIndex);
-                        }
-                        return symbol;
-                }
-
-                public static uint ReverseDecode(BitDecoder[] Models, UInt32 startIndex,
-                        RangeCoder.Decoder rangeDecoder, int NumBitLevels)
-                {
-                        uint m = 1;
-                        uint symbol = 0;
-                        for (int bitIndex = 0; bitIndex < NumBitLevels; bitIndex++)
-                        {
-                                uint bit = Models[startIndex + m].Decode(rangeDecoder);
-                                m <<= 1;
-                                m += bit;
-                                symbol |= (bit << bitIndex);
-                        }
-                        return symbol;
-                }
-        }
-}