--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/misc/libphysfs/lzma/CS/7zip/Compress/RangeCoder/RangeCoderBitTree.cs	Mon Apr 10 12:06:43 2017 -0400
@@ -0,0 +1,157 @@
+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;
+		}
+	}
+}