Clear up ZlibInStream::reset() behaviour

It previously only did a reset of the ZlibInStream object, not the
underlying zlib stream. It also had the side effect of flushing
the underlying stream and disassociating from it.

Clear things up by changing the naming, and introducing a proper
reset function (which is needed by the Tight decoder).

common/rdr/ZlibInStream.cxx

@@ -16,6 +16,8 @@
  * USA.
  */
 
+#include <assert.h>
+
 #include <rdr/ZlibInStream.h>
 #include <rdr/Exception.h>
 #include <zlib.h>
@@ -26,26 +28,16 @@ enum { DEFAULT_BUF_SIZE = 16384 };
 
 ZlibInStream::ZlibInStream(int bufSize_)
   : underlying(0), bufSize(bufSize_ ? bufSize_ : DEFAULT_BUF_SIZE), offset(0),
-    bytesIn(0)
+    zs(NULL), bytesIn(0)
 {
-  zs = new z_stream;
-  zs->zalloc    = Z_NULL;
-  zs->zfree     = Z_NULL;
-  zs->opaque    = Z_NULL;
-  zs->next_in   = Z_NULL;
-  zs->avail_in  = 0;
-  if (inflateInit(zs) != Z_OK) {
-    delete zs;
-    throw Exception("ZlibInStream: inflateInit failed");
-  }
   ptr = end = start = new U8[bufSize];
+  init();
 }
 
 ZlibInStream::~ZlibInStream()
 {
+  deinit();
   delete [] start;
-  inflateEnd(zs);
-  delete zs;
 }
 
 void ZlibInStream::setUnderlying(InStream* is, int bytesIn_)
@@ -60,7 +52,7 @@ int ZlibInStream::pos()
   return offset + ptr - start;
 }
 
-void ZlibInStream::reset()
+void ZlibInStream::removeUnderlying()
 {
   ptr = end = start;
   if (!underlying) return;
@@ -72,6 +64,38 @@ void ZlibInStream::reset()
   underlying = 0;
 }
 
+void ZlibInStream::reset()
+{
+  deinit();
+  init();
+}
+
+void ZlibInStream::init()
+{
+  assert(zs == NULL);
+
+  zs = new z_stream;
+  zs->zalloc    = Z_NULL;
+  zs->zfree     = Z_NULL;
+  zs->opaque    = Z_NULL;
+  zs->next_in   = Z_NULL;
+  zs->avail_in  = 0;
+  if (inflateInit(zs) != Z_OK) {
+    delete zs;
+    zs = NULL;
+    throw Exception("ZlibInStream: inflateInit failed");
+  }
+}
+
+void ZlibInStream::deinit()
+{
+  assert(zs != NULL);
+  removeUnderlying();
+  inflateEnd(zs);
+  delete zs;
+  zs = NULL;
+}
+
 int ZlibInStream::overrun(int itemSize, int nItems, bool wait)
 {
   if (itemSize > bufSize)

common/rdr/ZlibInStream.h

@@ -38,11 +38,15 @@ namespace rdr {
     virtual ~ZlibInStream();
 
     void setUnderlying(InStream* is, int bytesIn);
-    void reset();
+    void removeUnderlying();
     int pos();
+    void reset();
 
   private:
 
+    void init();
+    void deinit();
+
     int overrun(int itemSize, int nItems, bool wait);
     bool decompress(bool wait);
 

common/rfb/TightDecoder.cxx

@@ -165,7 +165,7 @@ void TightDecoder::decodeRect(const Rect& r, const void* buffer,
   bufptr += 1;
   buflen -= 1;
 
-  // Flush zlib streams if we are told by the server to do so.
+  // Reset zlib streams if we are told by the server to do so.
   for (int i = 0; i < 4; i++) {
     if (comp_ctl & 1) {
       zis[i].reset();
@@ -309,8 +309,8 @@ void TightDecoder::decodeRect(const Rect& r, const void* buffer,
     netbuf = new rdr::U8[dataSize];
 
     zis[streamId].readBytes(netbuf, dataSize);
-    zis[streamId].reset();
 
+    zis[streamId].removeUnderlying();
     delete ms;
 
     bufptr = netbuf;

common/rfb/zrleDecode.h

@@ -177,7 +177,7 @@ void ZRLE_DECODE (const Rect& r, rdr::InStream* is,
     }
   }
 
-  zis->reset();
+  zis->removeUnderlying();
 }
 
 #undef ZRLE_DECODE