diff options
Diffstat (limited to 'other-licenses/7zstub/src/CS/7zip/Compress/RangeCoder/RangeCoder.cs')
| -rw-r--r-- | other-licenses/7zstub/src/CS/7zip/Compress/RangeCoder/RangeCoder.cs | 234 |
1 files changed, 234 insertions, 0 deletions
diff --git a/other-licenses/7zstub/src/CS/7zip/Compress/RangeCoder/RangeCoder.cs b/other-licenses/7zstub/src/CS/7zip/Compress/RangeCoder/RangeCoder.cs new file mode 100644 index 0000000000..4ced2477e4 --- /dev/null +++ b/other-licenses/7zstub/src/CS/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(); }
+ }
+}
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