Implement WebSocketDeflater.

net/websockets/websocket_deflater.h

+// Copyright (c) 2013 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.
+
+#ifndef NET_WEBSOCKETS_WEBSOCKET_DEFLATER_H_
+#define NET_WEBSOCKETS_WEBSOCKET_DEFLATER_H_
+
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "third_party/zlib/zlib.h"
+
+namespace net {
+
+class IOBufferWithSize;
+
+class WebSocketDeflater {
+ public:
+  enum ContextTakeOverMode {
+    DO_NOT_TAKE_OVER_CONTEXT,
+    TAKE_OVER_CONTEXT,
+  };
+
+  // |window_bits| must be between 8 and 15 (both inclusive).
+  WebSocketDeflater(int window_bits, ContextTakeOverMode mode);
+  ~WebSocketDeflater();
+
+  // Adds bytes to |stream_|.
+  // Returns true if there is no error and false otherwise.
+  bool AddBytes(const char* data, size_t size);
+
+  // Flushes and returns deflated result.
+  // Returns null if there is an error.
+  scoped_refptr<IOBufferWithSize> Finish();
+
+ private:
+  void Reset();
+
+  scoped_ptr<z_stream> stream_;
+  ContextTakeOverMode mode_;
+  std::vector<char> buffer_;
+  bool are_bytes_added_;
+
+  DISALLOW_COPY_AND_ASSIGN(WebSocketDeflater);
+};
+
+}  // namespace net
+
+#endif  // NET_WEBSOCKETS_WEBSOCKET_DEFLATER_H_