EncoderZlib/DecoderZlib for chromoting

remoting/base/compressor_zlib.cc

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "remoting/base/compressor_zlib.h"
 
 #if defined(USE_SYSTEM_ZLIB)
 #include <zlib.h>
 // The code below uses the MOZ_Z_ forms of these functions in order that things
 // should work on Windows. In order to make this code cross platform, we map
@@ skipping 19 matching lines @@
 
   deflateInit(stream_.get(), Z_BEST_SPEED);
 }
 
 CompressorZlib::~CompressorZlib() {
   deflateEnd(stream_.get());
 }
 
 bool CompressorZlib::Process(const uint8* input_data, int input_size,
                              uint8* output_data, int output_size,
-                             int* consumed, int* written) {
+                             CompressorFlush flush, int* consumed,
+                             int* written) {
   DCHECK_GT(output_size, 0);
 
   // Setup I/O parameters.
   stream_->avail_in = input_size;
   stream_->next_in = (Bytef*)input_data;
   stream_->avail_out = output_size;
   stream_->next_out = (Bytef*)output_data;
 
-  int ret = deflate(stream_.get(), input_size ? Z_NO_FLUSH : Z_FINISH);
+  int z_flush = 0;
+  if (flush == CompressorSyncFlush) {
+    z_flush = Z_SYNC_FLUSH;
+  } else if (flush == CompressorFinish) {
+    z_flush = Z_FINISH;
+  } else if (flush == CompressorNoFlush) {
+    z_flush = Z_NO_FLUSH;
+  } else {
+    NOTREACHED() << "Unsupported flush mode";
+  }
+
+  int ret = deflate(stream_.get(), z_flush);
   if (ret == Z_STREAM_ERROR) {
     NOTREACHED() << "zlib compression failed";
   }
 
   *consumed = input_size - stream_->avail_in;
   *written = output_size - stream_->avail_out;
 
-  // Return true when we get Z_BUF_ERROR, this way we can feed more data
-  // to zlib.
-  return ret == Z_OK || ret == Z_BUF_ERROR;
+  // If |ret| equals Z_STREAM_END we have reached the end of stream.
+  // If |ret| equals Z_BUF_ERROR we have the end of the synchronication point.
+  // For these two cases we need to stop compressing.
+  if (ret == Z_OK) {
+    return true;
+  } else if (ret == Z_STREAM_END) {
+    return false;
+  } else if (ret == Z_BUF_ERROR) {
+    return stream_->avail_out == 0;
+  } else {
+    NOTREACHED() << "Unexpected zlib error: " << ret;
+    return false;
+  }
 }
 
 }  // namespace remoting