4.20

7zip/Compress/Z/ZDecoder.cpp

@@ -0,0 +1,172 @@
+// ZDecoder.cpp
+
+#include "StdAfx.h"
+
+#include "ZDecoder.h"
+
+#include "../../../Common/Alloc.h"
+#include "../../Common/InBuffer.h"
+#include "../../Common/OutBuffer.h"
+#include "../../Common/LSBFDecoder.h"
+
+namespace NCompress {
+namespace NZ {
+
+static const UInt32 kBufferSize = (1 << 20);
+static const Byte kNumBitsMask = 0x1F;   
+static const Byte kBlockModeMask = 0x80;   
+static const int kNumMinBits = 9;   
+static const int kNumMaxBits = 16;   
+
+void CDecoder::Free()
+{
+  MyFree(_parents);
+  _parents = 0;
+  MyFree(_suffixes);
+  _suffixes = 0;
+  MyFree(_stack);
+  _stack = 0;
+}
+
+bool CDecoder::Alloc(size_t numItems)
+{
+  Free();
+  _parents = (UInt16 *)MyAlloc(numItems * sizeof(UInt16));
+  if (_parents == 0)
+    return false;
+  _suffixes = (Byte *)MyAlloc(numItems * sizeof(Byte));
+  if (_suffixes == 0)
+    return false;
+  _stack = (Byte *)MyAlloc(numItems * sizeof(Byte));
+  return _stack != 0;
+}
+
+CDecoder::~CDecoder()
+{
+  Free();
+}
+
+STDMETHODIMP CDecoder::CodeReal(ISequentialInStream *inStream,
+    ISequentialOutStream *outStream, const UInt64 *inSize, const UInt64 *outSize,
+    ICompressProgressInfo *progress)
+{
+  NStream::NLSBF::CBaseDecoder<CInBuffer> inBuffer;
+  COutBuffer outBuffer;
+
+  if (!inBuffer.Create(kBufferSize))
+    return E_OUTOFMEMORY;
+  inBuffer.SetStream(inStream);
+  inBuffer.Init();
+
+  if (!outBuffer.Create(kBufferSize))
+    return E_OUTOFMEMORY;
+  outBuffer.SetStream(outStream);
+  outBuffer.Init();
+
+  int	maxbits = _properties & kNumBitsMask;
+  if (maxbits < kNumMinBits || maxbits > kNumMaxBits)
+    return S_FALSE;
+  UInt32 numItems = 1 << maxbits;
+  bool blockMode = ((_properties & kBlockModeMask) != 0);
+  if (!blockMode)
+    return E_NOTIMPL;
+
+  if (maxbits != _numMaxBits || _parents == 0 || _suffixes == 0 || _stack == 0)
+  {
+    if (!Alloc(numItems))
+      return E_OUTOFMEMORY;
+    _numMaxBits = maxbits;
+  }
+
+  UInt64 prevPos = 0;
+  int numBits = kNumMinBits;
+  UInt32 head = blockMode ? 257 : 256;
+
+  bool needPrev = false;
+
+  int keepBits = 0;
+
+  _parents[256] = 0; // virus protection
+  _suffixes[256] = 0;
+
+  while (true)
+  {
+    if (keepBits < numBits)
+      keepBits = numBits * 8;
+    UInt32 symbol = inBuffer.ReadBits(numBits);
+    if (inBuffer.ExtraBitsWereRead())
+      break;
+    keepBits -= numBits;
+    if (symbol >= head)
+      return S_FALSE;
+    if (blockMode && symbol == 256)
+    {
+      for (;keepBits > 0; keepBits--)
+        inBuffer.ReadBits(1);
+      numBits = kNumMinBits;
+      head = 257;
+      needPrev = false;
+      continue;
+    }
+    UInt32 cur = symbol;
+    int i = 0;
+    while (cur >= 256)
+    {
+      _stack[i++] = _suffixes[cur];
+      cur = _parents[cur];
+    }
+    _stack[i++] = (Byte)cur;
+    if (needPrev)
+    {
+      _suffixes[head - 1] = (Byte)cur;
+      if (symbol == head - 1)
+        _stack[0] = (Byte)cur;
+    }
+    while (i > 0)
+      outBuffer.WriteByte((_stack[--i]));
+    if (head < numItems)
+    {
+      needPrev = true;
+      _parents[head++] = (UInt16)symbol;
+      if (head > ((UInt32)1 << numBits))
+      {
+        if (numBits < maxbits)
+        {
+          numBits++;
+          keepBits = numBits * 8;
+        }
+      }
+    }
+    else
+      needPrev = false;
+
+    UInt64 nowPos = outBuffer.GetProcessedSize();
+    if (progress != NULL && nowPos - prevPos > (1 << 18))
+    {
+      prevPos = nowPos;
+      UInt64 packSize = inBuffer.GetProcessedSize();
+      RINOK(progress->SetRatioInfo(&packSize, &nowPos));
+    }
+  }
+  return outBuffer.Flush();
+}
+
+STDMETHODIMP CDecoder::Code(ISequentialInStream *inStream,
+    ISequentialOutStream *outStream, const UInt64 *inSize, const UInt64 *outSize,
+    ICompressProgressInfo *progress)
+{
+  try { return CodeReal(inStream, outStream, inSize, outSize, progress); }
+  catch(const CInBufferException &e) { return e.ErrorCode; }
+  catch(const COutBufferException &e) { return e.ErrorCode; }
+  catch(...) { return S_FALSE; }
+}
+
+STDMETHODIMP CDecoder::SetDecoderProperties2(const Byte *data, UInt32 size)
+{
+  if (size < 1)
+    return E_INVALIDARG;
+  _properties = data[0];
+  return S_OK;
+}
+
+}}