preparing update of physfs

2026-08-20 20:51:22 +02:00 · 2013-12-20 21:19:16 +01:00
parent f95fbc8a70
commit 3a8901d831
579 changed files with 0 additions and 0 deletions
@@ -0,0 +1,120 @@
+// Compress/RangeCoder/RangeCoderBit.h
+
+#ifndef __COMPRESS_RANGECODER_BIT_H
+#define __COMPRESS_RANGECODER_BIT_H
+
+#include "RangeCoder.h"
+
+namespace NCompress {
+namespace NRangeCoder {
+
+const int kNumBitModelTotalBits  = 11;
+const UInt32 kBitModelTotal = (1 << kNumBitModelTotalBits);
+
+const int kNumMoveReducingBits = 2;
+
+const int kNumBitPriceShiftBits = 6;
+const UInt32 kBitPrice = 1 << kNumBitPriceShiftBits;
+
+class CPriceTables
+{
+public:
+  static UInt32 ProbPrices[kBitModelTotal >> kNumMoveReducingBits];
+  static void Init();
+  CPriceTables();
+};
+
+template <int numMoveBits>
+class CBitModel
+{
+public:
+  UInt32 Prob;
+  void UpdateModel(UInt32 symbol)
+  {
+    /*
+    Prob -= (Prob + ((symbol - 1) & ((1 << numMoveBits) - 1))) >> numMoveBits;
+    Prob += (1 - symbol) << (kNumBitModelTotalBits - numMoveBits);
+    */
+    if (symbol == 0)
+      Prob += (kBitModelTotal - Prob) >> numMoveBits;
+    else
+      Prob -= (Prob) >> numMoveBits;
+  }
+public:
+  void Init() { Prob = kBitModelTotal / 2; }
+};
+
+template <int numMoveBits>
+class CBitEncoder: public CBitModel<numMoveBits>
+{
+public:
+  void Encode(CEncoder *encoder, UInt32 symbol)
+  {
+    /*
+    encoder->EncodeBit(this->Prob, kNumBitModelTotalBits, symbol);
+    this->UpdateModel(symbol);
+    */
+    UInt32 newBound = (encoder->Range >> kNumBitModelTotalBits) * this->Prob;
+    if (symbol == 0)
+    {
+      encoder->Range = newBound;
+      this->Prob += (kBitModelTotal - this->Prob) >> numMoveBits;
+    }
+    else
+    {
+      encoder->Low += newBound;
+      encoder->Range -= newBound;
+      this->Prob -= (this->Prob) >> numMoveBits;
+    }
+    if (encoder->Range < kTopValue)
+    {
+      encoder->Range <<= 8;
+      encoder->ShiftLow();
+    }
+  }
+  UInt32 GetPrice(UInt32 symbol) const
+  {
+    return CPriceTables::ProbPrices[
+      (((this->Prob - symbol) ^ ((-(int)symbol))) & (kBitModelTotal - 1)) >> kNumMoveReducingBits];
+  }
+  UInt32 GetPrice0() const { return CPriceTables::ProbPrices[this->Prob >> kNumMoveReducingBits]; }
+  UInt32 GetPrice1() const { return CPriceTables::ProbPrices[(kBitModelTotal - this->Prob) >> kNumMoveReducingBits]; }
+};
+
+
+template <int numMoveBits>
+class CBitDecoder: public CBitModel<numMoveBits>
+{
+public:
+  UInt32 Decode(CDecoder *decoder)
+  {
+    UInt32 newBound = (decoder->Range >> kNumBitModelTotalBits) * this->Prob;
+    if (decoder->Code < newBound)
+    {
+      decoder->Range = newBound;
+      this->Prob += (kBitModelTotal - this->Prob) >> numMoveBits;
+      if (decoder->Range < kTopValue)
+      {
+        decoder->Code = (decoder->Code << 8) | decoder->Stream.ReadByte();
+        decoder->Range <<= 8;
+      }
+      return 0;
+    }
+    else
+    {
+      decoder->Range -= newBound;
+      decoder->Code -= newBound;
+      this->Prob -= (this->Prob) >> numMoveBits;
+      if (decoder->Range < kTopValue)
+      {
+        decoder->Code = (decoder->Code << 8) | decoder->Stream.ReadByte();
+        decoder->Range <<= 8;
+      }
+      return 1;
+    }
+  }
+};
+
+}}
+
+#endif