Zlib compressor 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
+// back to the normal functions here in the case that we are using the system
+// zlib.
+#define MOZ_Z_deflate deflate
+#define MOZ_Z_deflateEnd deflateEnd
+#define MOZ_Z_deflateInit_ deflateInit_
+#else
+#include "third_party/zlib/zlib.h"
+#endif
+#include "base/logging.h"
+
+namespace remoting {
+
+CompressorZlib::CompressorZlib() {
+  stream_.reset(new z_stream());
+
+  stream_->next_in = Z_NULL;
+  stream_->zalloc = Z_NULL;
+  stream_->zfree = Z_NULL;
+  stream_->opaque = Z_NULL;
+
+  deflateInit(stream_.get(), Z_BEST_SPEED);
+}
+
+CompressorZlib::~CompressorZlib() {
+  deflateEnd(stream_.get());
+}
+
+void CompressorZlib::Write(const uint8* input_data, int input_size,
+                           uint8* output_data, int output_size,
+                           int* consumed, int* written) {
+  // 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(), Z_NO_FLUSH);
+  if (ret == Z_STREAM_ERROR) {
+    NOTREACHED() << "zlib compression failed";
+  }
+
+  *consumed = input_size - stream_->avail_in;
+  *written = output_size - stream_->avail_out;
+}
+
+bool CompressorZlib::Flush(uint8* output_data, int output_size,
+                           int* written) {
+  // Setup I/O parameters.
+  stream_->avail_in = 0;
+  stream_->next_in = NULL;
+  stream_->avail_out = output_size;
+  stream_->next_out = (Bytef*)output_data;
+
+  int ret = deflate(stream_.get(), Z_FINISH);
+  if (ret == Z_STREAM_ERROR) {
+    NOTREACHED() << "zlib compression failed";
+  }
+
+  *written = output_size - stream_->avail_out;
+  return ret == Z_OK;
+}
+
+}  // namespace remoting