Implemented support for changing zlib compression levels from the

Tight encoder.


git-svn-id: svn://svn.code.sf.net/p/tigervnc/code/trunk@334 3789f03b-4d11-0410-bbf8-ca57d06f2519

rdr/ZlibOutStream.cxx

@@ -25,7 +25,8 @@ using namespace rdr;
 enum { DEFAULT_BUF_SIZE = 16384 };
 
 ZlibOutStream::ZlibOutStream(OutStream* os, int bufSize_, int compressLevel)
-  : underlying(os), bufSize(bufSize_ ? bufSize_ : DEFAULT_BUF_SIZE), offset(0)
+  : underlying(os), compressionLevel(compressLevel), newLevel(compressLevel),
+    bufSize(bufSize_ ? bufSize_ : DEFAULT_BUF_SIZE), offset(0)
 {
   zs = new z_stream;
   zs->zalloc    = Z_NULL;
@@ -55,6 +56,14 @@ void ZlibOutStream::setUnderlying(OutStream* os)
   underlying = os;
 }
 
+void ZlibOutStream::setCompressionLevel(int level)
+{
+  if (level < -1 || level > 9)
+    level = -1;                 // Z_DEFAULT_COMPRESSION
+
+  newLevel = level;
+}
+
 int ZlibOutStream::length()
 {
   return offset + ptr - start;
@@ -76,6 +85,7 @@ void ZlibOutStream::flush()
 
 //        fprintf(stderr,"zos flush: calling deflate, avail_in %d, avail_out %d\n",
 //                zs->avail_in,zs->avail_out);
+      checkCompressionLevel();
       int rc = deflate(zs, Z_SYNC_FLUSH);
       if (rc != Z_OK) throw Exception("ZlibOutStream: deflate failed");
 
@@ -109,6 +119,7 @@ int ZlibOutStream::overrun(int itemSize, int nItems)
 //        fprintf(stderr,"zos overrun: calling deflate, avail_in %d, avail_out %d\n",
 //                zs->avail_in,zs->avail_out);
 
+      checkCompressionLevel();
       int rc = deflate(zs, 0);
       if (rc != Z_OK) throw Exception("ZlibOutStream: deflate failed");
 
@@ -138,3 +149,13 @@ int ZlibOutStream::overrun(int itemSize, int nItems)
 
   return nItems;
 }
+
+void ZlibOutStream::checkCompressionLevel()
+{
+  if (newLevel != compressionLevel) {
+    if (deflateParams (zs, newLevel, Z_DEFAULT_STRATEGY) != Z_OK) {
+      throw Exception("ZlibOutStream: deflateParams failed");
+    }
+    compressionLevel = newLevel;
+  }
+}

rdr/ZlibOutStream.h

@@ -38,14 +38,18 @@ namespace rdr {
     virtual ~ZlibOutStream();
 
     void setUnderlying(OutStream* os);
+    void setCompressionLevel(int level=-1);
     void flush();
     int length();
 
   private:
 
     int overrun(int itemSize, int nItems);
+    void checkCompressionLevel();
 
     OutStream* underlying;
+    int compressionLevel;
+    int newLevel;
     int bufSize;
     int offset;
     z_stream_s* zs;

rfb/tightEncode.h

@@ -192,6 +192,7 @@ static void compressData(rdr::OutStream *os, rdr::ZlibOutStream *zos,
     //        Maybe use the same static object used in the JPEG coder?
     rdr::MemOutStream mem_os;
     zos->setUnderlying(&mem_os);
+    zos->setCompressionLevel(zlibLevel);
     zos->writeBytes(buf, length);
     zos->flush();
     os->writeCompactLength(mem_os.length());