summaryrefslogtreecommitdiffstats
path: root/CS/7zip/Compress/RangeCoder/RangeCoderBitTree.cs
diff options
context:
space:
mode:
Diffstat (limited to 'CS/7zip/Compress/RangeCoder/RangeCoderBitTree.cs')
-rwxr-xr-xCS/7zip/Compress/RangeCoder/RangeCoderBitTree.cs157
1 files changed, 157 insertions, 0 deletions
diff --git a/CS/7zip/Compress/RangeCoder/RangeCoderBitTree.cs b/CS/7zip/Compress/RangeCoder/RangeCoderBitTree.cs
new file mode 100755
index 0000000..3309c14
--- /dev/null
+++ b/CS/7zip/Compress/RangeCoder/RangeCoderBitTree.cs
@@ -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;
+ }
+ }
+}