1 files changed, 32 insertions, 1 deletions

diff --git a/CPP/7zip/Compress/ZlibDecoder.h b/CPP/7zip/Compress/ZlibDecoder.h
index 95c11002..8c5e73b0 100755..100644
--- a/CPP/7zip/Compress/ZlibDecoder.h
+++ b/CPP/7zip/Compress/ZlibDecoder.h
@@ -16,13 +16,15 @@ class COutStreamWithAdler:
 {
   CMyComPtr<ISequentialOutStream> _stream;
   UInt32 _adler;
+  UInt64 _size;
 public:
   MY_UNKNOWN_IMP
   STDMETHOD(Write)(const void *data, UInt32 size, UInt32 *processedSize);
   void SetStream(ISequentialOutStream *stream) { _stream = stream; }
   void ReleaseStream() { _stream.Release(); }
-  void Init() { _adler = ADLER_INIT_VAL; }
+  void Init() { _adler = ADLER_INIT_VAL; _size = 0; }
   UInt32 GetAdler() const { return _adler; }
+  UInt64 GetSize() const { return _size; }
 };
 
 class CDecoder:
@@ -39,10 +41,39 @@ public:
       const UInt64 *inSize, const UInt64 *outSize, ICompressProgressInfo *progress);
 
   UInt64 GetInputProcessedSize() const { return DeflateDecoderSpec->GetInputProcessedSize() + 2; }
+  UInt64 GetOutputProcessedSize() const { return AdlerSpec->GetSize(); }
 
   MY_UNKNOWN_IMP
 };
 
+static bool inline IsZlib(const Byte *p)
+{
+  if ((p[0] & 0xF) != 8) // method
+    return false;
+  if (((unsigned)p[0] >> 4) > 7) // logar_window_size minus 8.
+    return false;
+  if ((p[1] & 0x20) != 0) // dictPresent
+    return false;
+  if ((((UInt32)p[0] << 8) + p[1]) % 31 != 0)
+    return false;
+  return true;
+}
+
+// IsZlib_3bytes checks 2 bytes of zlib header and starting byte of Deflate stream
+
+static bool inline IsZlib_3bytes(const Byte *p)
+{
+  if (!IsZlib(p))
+    return false;
+  unsigned val = p[2];
+  unsigned blockType = (val >> 1) & 0x3;
+  if (blockType == 3) // unsupported block type for deflate
+    return false;
+  if (blockType == NCompress::NDeflate::NBlockType::kStored && (val >> 3) != 0)
+    return false;
+  return true;
+}
+
 }}
 
 #endif