Initialer Commit

CPP/7zip/Compress/ZlibDecoder.cpp

@@ -0,0 +1,92 @@
+// ZlibDecoder.cpp
+
+#include "StdAfx.h"
+
+#include "../Common/StreamUtils.h"
+
+#include "ZlibDecoder.h"
+
+namespace NCompress {
+namespace NZlib {
+
+#define DEFLATE_TRY_BEGIN try {
+#define DEFLATE_TRY_END } catch(...) { return S_FALSE; }
+
+#define ADLER_MOD 65521
+#define ADLER_LOOP_MAX 5550
+
+UInt32 Adler32_Update(UInt32 adler, const Byte *buf, size_t size)
+{
+  UInt32 a = adler & 0xFFFF;
+  UInt32 b = (adler >> 16) & 0xFFFF;
+  while (size > 0)
+  {
+    unsigned curSize = (size > ADLER_LOOP_MAX) ? ADLER_LOOP_MAX : (unsigned )size;
+    unsigned i;
+    for (i = 0; i < curSize; i++)
+    {
+      a += buf[i];
+      b += a;
+    }
+    buf += curSize;
+    size -= curSize;
+    a %= ADLER_MOD;
+    b %= ADLER_MOD;
+  }
+  return (b << 16) + a;
+}
+
+STDMETHODIMP COutStreamWithAdler::Write(const void *data, UInt32 size, UInt32 *processedSize)
+{
+  HRESULT result = S_OK;
+  if (_stream)
+    result = _stream->Write(data, size, &size);
+  _adler = Adler32_Update(_adler, (const Byte *)data, size);
+  _size += size;
+  if (processedSize)
+    *processedSize = size;
+  return result;
+}
+
+STDMETHODIMP CDecoder::Code(ISequentialInStream *inStream, ISequentialOutStream *outStream,
+    const UInt64 *inSize, const UInt64 *outSize, ICompressProgressInfo *progress)
+{
+  DEFLATE_TRY_BEGIN
+  if (!AdlerStream)
+    AdlerStream = AdlerSpec = new COutStreamWithAdler;
+  if (!DeflateDecoder)
+  {
+    DeflateDecoderSpec = new NDeflate::NDecoder::CCOMCoder;
+    DeflateDecoderSpec->ZlibMode = true;
+    DeflateDecoder = DeflateDecoderSpec;
+  }
+
+  if (inSize && *inSize < 2)
+    return S_FALSE;
+  Byte buf[2];
+  RINOK(ReadStream_FALSE(inStream, buf, 2));
+  if (!IsZlib(buf))
+    return S_FALSE;
+
+  AdlerSpec->SetStream(outStream);
+  AdlerSpec->Init();
+  
+  UInt64 inSize2 = 0;
+  if (inSize)
+    inSize2 = *inSize - 2;
+
+  HRESULT res = DeflateDecoder->Code(inStream, AdlerStream, inSize ? &inSize2 : NULL, outSize, progress);
+  AdlerSpec->ReleaseStream();
+
+  if (res == S_OK)
+  {
+    const Byte *p = DeflateDecoderSpec->ZlibFooter;
+    UInt32 adler = ((UInt32)p[0] << 24) | ((UInt32)p[1] << 16) | ((UInt32)p[2] << 8) | p[3];
+    if (adler != AdlerSpec->GetAdler())
+      return S_FALSE;
+  }
+  return res;
+  DEFLATE_TRY_END
+}
+
+}}