Initialer Commit

CPP/7zip/Compress/LzmsDecoder.h

@@ -0,0 +1,271 @@
+// LzmsDecoder.h
+// The code is based on LZMS description from wimlib code
+
+#ifndef __LZMS_DECODER_H
+#define __LZMS_DECODER_H
+
+// #define SHOW_DEBUG_INFO
+
+#ifdef SHOW_DEBUG_INFO
+#include <stdio.h>
+#define PRF(x) x
+#else
+// #define PRF(x)
+#endif
+
+#include "../../../C/CpuArch.h"
+#include "../../../C/HuffEnc.h"
+
+#include "../../Common/MyBuffer.h"
+#include "../../Common/MyCom.h"
+
+#include "../ICoder.h"
+
+#include "HuffmanDecoder.h"
+
+namespace NCompress {
+namespace NLzms {
+
+class CBitDecoder
+{
+public:
+  const Byte *_buf;
+  unsigned _bitPos;
+
+  void Init(const Byte *buf, size_t size) throw()
+  {
+    _buf = buf + size;
+    _bitPos = 0;
+  }
+
+  UInt32 GetValue(unsigned numBits) const
+  {
+    UInt32 v = ((UInt32)_buf[-1] << 16) | ((UInt32)_buf[-2] << 8) | (UInt32)_buf[-3];
+    v >>= (24 - numBits - _bitPos);
+    return v & ((1 << numBits) - 1);
+  }
+  
+  void MovePos(unsigned numBits)
+  {
+    _bitPos += numBits;
+    _buf -= (_bitPos >> 3);
+    _bitPos &= 7;
+  }
+
+  UInt32 ReadBits32(unsigned numBits)
+  {
+    UInt32 mask = (((UInt32)1 << numBits) - 1);
+    numBits += _bitPos;
+    const Byte *buf = _buf;
+    UInt32 v = GetUi32(buf - 4);
+    if (numBits > 32)
+    {
+      v <<= (numBits - 32);
+      v |= (UInt32)buf[-5] >> (40 - numBits);
+    }
+    else
+      v >>= (32 - numBits);
+    _buf = buf - (numBits >> 3);
+    _bitPos = numBits & 7;
+    return v & mask;
+  }
+};
+
+
+const unsigned k_NumLitSyms = 256;
+const unsigned k_NumLenSyms = 54;
+const unsigned k_NumPosSyms = 799;
+const unsigned k_NumPowerSyms = 8;
+
+const unsigned k_NumProbBits = 6;
+const unsigned k_ProbLimit = 1 << k_NumProbBits;
+const unsigned k_InitialProb = 48;
+const UInt32 k_InitialHist = 0x55555555;
+
+const unsigned k_NumReps = 3;
+
+const unsigned k_NumMainProbs  = 16;
+const unsigned k_NumMatchProbs = 32;
+const unsigned k_NumRepProbs   = 64;
+
+const unsigned k_NumHuffmanBits = 15;
+
+template <UInt32 m_NumSyms, UInt32 m_RebuildFreq, unsigned numTableBits>
+class CHuffDecoder: public NCompress::NHuffman::CDecoder<k_NumHuffmanBits, m_NumSyms, numTableBits>
+{
+public:
+  UInt32 RebuildRem;
+  UInt32 NumSyms;
+  UInt32 Freqs[m_NumSyms];
+
+  void Generate() throw()
+  {
+    UInt32 vals[m_NumSyms];
+    Byte levels[m_NumSyms];
+
+    // We need to check that our algorithm is OK, when optimal Huffman tree uses more than 15 levels !!!
+    Huffman_Generate(Freqs, vals, levels, NumSyms, k_NumHuffmanBits);
+
+    /*
+    for (UInt32 i = NumSyms; i < m_NumSyms; i++)
+      levels[i] = 0;
+    */
+    this->BuildFull(levels, NumSyms);
+  }
+  
+  void Rebuild() throw()
+  {
+    Generate();
+    RebuildRem = m_RebuildFreq;
+    UInt32 num = NumSyms;
+    for (UInt32 i = 0; i < num; i++)
+      Freqs[i] = (Freqs[i] >> 1) + 1;
+  }
+
+public:
+  void Init(UInt32 numSyms = m_NumSyms) throw()
+  {
+    RebuildRem = m_RebuildFreq;
+    NumSyms = numSyms;
+    for (UInt32 i = 0; i < numSyms; i++)
+      Freqs[i] = 1;
+    // for (; i < m_NumSyms; i++) Freqs[i] = 0;
+    Generate();
+  }
+};
+
+
+struct CProbEntry
+{
+  UInt32 Prob;
+  UInt64 Hist;
+
+  void Init()
+  {
+    Prob = k_InitialProb;
+    Hist = k_InitialHist;
+  }
+
+  UInt32 GetProb() const throw()
+  {
+    UInt32 prob = Prob;
+    if (prob == 0)
+      prob = 1;
+    else if (prob == k_ProbLimit)
+      prob = k_ProbLimit - 1;
+    return prob;
+  }
+
+  void Update(unsigned bit) throw()
+  {
+    Prob += (Int32)(Hist >> (k_ProbLimit - 1)) - (Int32)bit;
+    Hist = (Hist << 1) | bit;
+  }
+};
+
+
+struct CRangeDecoder
+{
+  UInt32 range;
+  UInt32 code;
+  const Byte *cur;
+  // const Byte *end;
+
+  void Init(const Byte *data, size_t /* size */) throw()
+  {
+    range = 0xFFFFFFFF;
+    code = (((UInt32)GetUi16(data)) << 16) | GetUi16(data + 2);
+    cur = data + 4;
+    // end = data + size;
+  }
+
+  void Normalize()
+  {
+    if (range <= 0xFFFF)
+    {
+      range <<= 16;
+      code <<= 16;
+      // if (cur >= end) throw 1;
+      code |= GetUi16(cur);
+      cur += 2;
+    }
+  }
+
+  unsigned Decode(UInt32 *state, UInt32 numStates, struct CProbEntry *probs)
+  {
+    UInt32 st = *state;
+    CProbEntry *entry = &probs[st];
+    st = (st << 1) & (numStates - 1);
+
+    UInt32 prob = entry->GetProb();
+
+    if (range <= 0xFFFF)
+    {
+      range <<= 16;
+      code <<= 16;
+      // if (cur >= end) throw 1;
+      code |= GetUi16(cur);
+      cur += 2;
+    }
+
+    UInt32 bound = (range >> k_NumProbBits) * prob;
+    
+    if (code < bound)
+    {
+      range = bound;
+      *state = st;
+      entry->Update(0);
+      return 0;
+    }
+    else
+    {
+      range -= bound;
+      code -= bound;
+      *state = st | 1;
+      entry->Update(1);
+      return 1;
+    }
+  }
+};
+
+
+class CDecoder
+{
+  // CRangeDecoder _rc;
+  // CBitDecoder _bs;
+  size_t _pos;
+
+  UInt32 _reps[k_NumReps + 1];
+  UInt64 _deltaReps[k_NumReps + 1];
+
+  UInt32 mainState;
+  UInt32 matchState;
+  UInt32 lzRepStates[k_NumReps];
+  UInt32 deltaRepStates[k_NumReps];
+
+  struct CProbEntry mainProbs[k_NumMainProbs];
+  struct CProbEntry matchProbs[k_NumMatchProbs];
+  
+  struct CProbEntry lzRepProbs[k_NumReps][k_NumRepProbs];
+  struct CProbEntry deltaRepProbs[k_NumReps][k_NumRepProbs];
+
+  CHuffDecoder<k_NumLitSyms, 1024, 9> m_LitDecoder;
+  CHuffDecoder<k_NumPosSyms, 1024, 9> m_PosDecoder;
+  CHuffDecoder<k_NumLenSyms, 512, 8> m_LenDecoder;
+  CHuffDecoder<k_NumPowerSyms, 512, 6> m_PowerDecoder;
+  CHuffDecoder<k_NumPosSyms, 1024, 9> m_DeltaDecoder;
+
+  Int32 *_x86_history;
+
+  HRESULT CodeReal(const Byte *in, size_t inSize, Byte *out, size_t outSize);
+public:
+  CDecoder();
+  ~CDecoder();
+
+  HRESULT Code(const Byte *in, size_t inSize, Byte *out, size_t outSize);
+  const size_t GetUnpackSize() const { return _pos; }
+};
+
+}}
+
+#endif