Initial commit

Unity Studio/7zip/Compress/RangeCoder/RangeCoder.cs

@@ -0,0 +1,234 @@
+using System;
+
+namespace SevenZip.Compression.RangeCoder
+{
+	class Encoder
+	{
+		public const uint kTopValue = (1 << 24);
+
+		System.IO.Stream Stream;
+
+		public UInt64 Low;
+		public uint Range;
+		uint _cacheSize;
+		byte _cache;
+
+		long StartPosition;
+
+		public void SetStream(System.IO.Stream stream)
+		{
+			Stream = stream;
+		}
+
+		public void ReleaseStream()
+		{
+			Stream = null;
+		}
+
+		public void Init()
+		{
+			StartPosition = Stream.Position;
+
+			Low = 0;
+			Range = 0xFFFFFFFF;
+			_cacheSize = 1;
+			_cache = 0;
+		}
+
+		public void FlushData()
+		{
+			for (int i = 0; i < 5; i++)
+				ShiftLow();
+		}
+
+		public void FlushStream()
+		{
+			Stream.Flush();
+		}
+
+		public void CloseStream()
+		{
+			Stream.Close();
+		}
+
+		public void Encode(uint start, uint size, uint total)
+		{
+			Low += start * (Range /= total);
+			Range *= size;
+			while (Range < kTopValue)
+			{
+				Range <<= 8;
+				ShiftLow();
+			}
+		}
+
+		public void ShiftLow()
+		{
+			if ((uint)Low < (uint)0xFF000000 || (uint)(Low >> 32) == 1)
+			{
+				byte temp = _cache;
+				do
+				{
+					Stream.WriteByte((byte)(temp + (Low >> 32)));
+					temp = 0xFF;
+				}
+				while (--_cacheSize != 0);
+				_cache = (byte)(((uint)Low) >> 24);
+			}
+			_cacheSize++;
+			Low = ((uint)Low) << 8;
+		}
+
+		public void EncodeDirectBits(uint v, int numTotalBits)
+		{
+			for (int i = numTotalBits - 1; i >= 0; i--)
+			{
+				Range >>= 1;
+				if (((v >> i) & 1) == 1)
+					Low += Range;
+				if (Range < kTopValue)
+				{
+					Range <<= 8;
+					ShiftLow();
+				}
+			}
+		}
+
+		public void EncodeBit(uint size0, int numTotalBits, uint symbol)
+		{
+			uint newBound = (Range >> numTotalBits) * size0;
+			if (symbol == 0)
+				Range = newBound;
+			else
+			{
+				Low += newBound;
+				Range -= newBound;
+			}
+			while (Range < kTopValue)
+			{
+				Range <<= 8;
+				ShiftLow();
+			}
+		}
+
+		public long GetProcessedSizeAdd()
+		{
+			return _cacheSize +
+				Stream.Position - StartPosition + 4;
+			// (long)Stream.GetProcessedSize();
+		}
+	}
+
+	class Decoder
+	{
+		public const uint kTopValue = (1 << 24);
+		public uint Range;
+		public uint Code;
+		// public Buffer.InBuffer Stream = new Buffer.InBuffer(1 << 16);
+		public System.IO.Stream Stream;
+
+		public void Init(System.IO.Stream stream)
+		{
+			// Stream.Init(stream);
+			Stream = stream;
+
+			Code = 0;
+			Range = 0xFFFFFFFF;
+			for (int i = 0; i < 5; i++)
+				Code = (Code << 8) | (byte)Stream.ReadByte();
+		}
+
+		public void ReleaseStream()
+		{
+			// Stream.ReleaseStream();
+			Stream = null;
+		}
+
+		public void CloseStream()
+		{
+			Stream.Close();
+		}
+
+		public void Normalize()
+		{
+			while (Range < kTopValue)
+			{
+				Code = (Code << 8) | (byte)Stream.ReadByte();
+				Range <<= 8;
+			}
+		}
+
+		public void Normalize2()
+		{
+			if (Range < kTopValue)
+			{
+				Code = (Code << 8) | (byte)Stream.ReadByte();
+				Range <<= 8;
+			}
+		}
+
+		public uint GetThreshold(uint total)
+		{
+			return Code / (Range /= total);
+		}
+
+		public void Decode(uint start, uint size, uint total)
+		{
+			Code -= start * Range;
+			Range *= size;
+			Normalize();
+		}
+
+		public uint DecodeDirectBits(int numTotalBits)
+		{
+			uint range = Range;
+			uint code = Code;
+			uint result = 0;
+			for (int i = numTotalBits; i > 0; i--)
+			{
+				range >>= 1;
+				/*
+				result <<= 1;
+				if (code >= range)
+				{
+					code -= range;
+					result |= 1;
+				}
+				*/
+				uint t = (code - range) >> 31;
+				code -= range & (t - 1);
+				result = (result << 1) | (1 - t);
+
+				if (range < kTopValue)
+				{
+					code = (code << 8) | (byte)Stream.ReadByte();
+					range <<= 8;
+				}
+			}
+			Range = range;
+			Code = code;
+			return result;
+		}
+
+		public uint DecodeBit(uint size0, int numTotalBits)
+		{
+			uint newBound = (Range >> numTotalBits) * size0;
+			uint symbol;
+			if (Code < newBound)
+			{
+				symbol = 0;
+				Range = newBound;
+			}
+			else
+			{
+				symbol = 1;
+				Code -= newBound;
+				Range -= newBound;
+			}
+			Normalize();
+			return symbol;
+		}
+
+		// ulong GetProcessedSize() {return Stream.GetProcessedSize(); }
+	}
+}