1 files changed, 149 insertions, 0 deletions
diff --git a/CPP/7zip/Compress/Shrink/ShrinkDecoder.cpp b/CPP/7zip/Compress/Shrink/ShrinkDecoder.cpp
new file mode 100755
index 00000000..12d1b8d0
--- /dev/null
+++ b/CPP/7zip/Compress/Shrink/ShrinkDecoder.cpp
@@ -0,0 +1,149 @@
+// ShrinkDecoder.cpp
+
+#include "StdAfx.h"
+
+#include "ShrinkDecoder.h"
+
+#include "../../../Common/Alloc.h"
+#include "../../Common/InBuffer.h"
+#include "../../Common/OutBuffer.h"
+#include "../../Common/LSBFDecoder.h"
+
+namespace NCompress {
+namespace NShrink {
+
+static const UInt32 kBufferSize = (1 << 20);
+
+static const int kNumMinBits = 9;   
+
+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();
+
+  UInt64 prevPos = 0;
+  int numBits = kNumMinBits;
+  UInt32 head = 257;
+
+  bool needPrev = false;
+
+  _parents[256] = 0; // virus protection
+  _suffixes[256] = 0;
+
+  int i;
+  for (i = 0; i < 257; i++)
+    _isFree[i] = false;
+  for (; i < kNumItems; i++)
+    _isFree[i] = true;
+
+  UInt32 lastSymbol = 0;
+  for (;;)
+  {
+    outBuffer.Flush();
+    UInt32 symbol = inBuffer.ReadBits(numBits);
+    if (inBuffer.ExtraBitsWereRead())
+      break;
+    if (_isFree[symbol])
+      return S_FALSE;
+    if (symbol == 256)
+    {
+      // fix it;
+      UInt32 symbol = inBuffer.ReadBits(numBits);
+      if (symbol == 1)
+      {
+        if (numBits < kNumMaxBits)
+          numBits++;
+      }
+      else if (symbol == 2)
+      {
+        /* 
+        maybe need delete prev also ?
+        if (needPrev)
+          _isFree[head - 1] = true;
+        */
+        for (i = 257; i < kNumItems; i++)
+          _isParent[i] = false;
+        for (i = 257; i < kNumItems; i++)
+          if (!_isFree[i])
+            _isParent[_parents[i]] = true;
+        for (i = 257; i < kNumItems; i++)
+          if (!_isParent[i])
+            _isFree[i] = true;
+        head = 257;
+        while(head < ((UInt32)1 << numBits) && !_isFree[head])
+          head++;
+        if (head < ((UInt32)1 << numBits))
+        {
+          needPrev = true;
+          _isFree[head] = false;
+          _parents[head] = (UInt16)lastSymbol;
+          head++;
+        }
+      }
+      else 
+        return S_FALSE;
+      continue;
+    }
+    UInt32 cur = symbol;
+    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]));
+    while(head < ((UInt32)1 << numBits) && !_isFree[head])
+      head++;
+    if (head < ((UInt32)1 << numBits))
+    {
+      needPrev = true;
+      _isFree[head] = false;
+      _parents[head] = (UInt16)symbol;
+      head++;
+    }
+    else
+      needPrev = false;
+    lastSymbol = symbol;
+
+    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; }
+}
+
+}}