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      1 /*
      2  * Copyright (C) 2012 Google Inc.  All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions are
      6  * met:
      7  *
      8  *     * Redistributions of source code must retain the above copyright
      9  * notice, this list of conditions and the following disclaimer.
     10  *     * Redistributions in binary form must reproduce the above
     11  * copyright notice, this list of conditions and the following disclaimer
     12  * in the documentation and/or other materials provided with the
     13  * distribution.
     14  *     * Neither the name of Google Inc. nor the names of its
     15  * contributors may be used to endorse or promote products derived from
     16  * this software without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 #ifndef WebSocketDeflater_h
     32 #define WebSocketDeflater_h
     33 
     34 #include "wtf/Noncopyable.h"
     35 #include "wtf/OwnPtr.h"
     36 #include "wtf/PassOwnPtr.h"
     37 #include "wtf/Vector.h"
     38 
     39 struct z_stream_s;
     40 typedef z_stream_s z_stream;
     41 
     42 namespace blink {
     43 
     44 class WebSocketDeflater {
     45     WTF_MAKE_FAST_ALLOCATED;
     46 public:
     47     // This enum is reused for histogram. When this needs to be modified, add a
     48     // new enum for histogram and convert mode values into values in the new
     49     // enum to keep new data consistent with old one.
     50     enum ContextTakeOverMode {
     51         DoNotTakeOverContext,
     52         TakeOverContext,
     53         ContextTakeOverModeMax,
     54     };
     55     static PassOwnPtr<WebSocketDeflater> create(int windowBits, ContextTakeOverMode = TakeOverContext);
     56 
     57     ~WebSocketDeflater();
     58 
     59     bool initialize();
     60     bool addBytes(const char*, size_t);
     61     bool finish();
     62     const char* data() { return m_buffer.data(); }
     63     size_t size() const { return m_buffer.size(); }
     64     // Reset the deflate result.
     65     void softReset();
     66     // Reset the deflate result and internal state if the take over mode is DoNotTakeOverContext.
     67     void reset();
     68 
     69 private:
     70     WebSocketDeflater(int windowBits, ContextTakeOverMode);
     71 
     72     int m_windowBits;
     73     ContextTakeOverMode m_contextTakeOverMode;
     74     bool m_isBytesAdded;
     75     Vector<char> m_buffer;
     76     OwnPtr<z_stream> m_stream;
     77 };
     78 
     79 class WebSocketInflater {
     80     WTF_MAKE_FAST_ALLOCATED;
     81 public:
     82     static PassOwnPtr<WebSocketInflater> create(int windowBits = 15);
     83 
     84     ~WebSocketInflater();
     85 
     86     bool initialize();
     87     bool addBytes(const char*, size_t);
     88     bool finish();
     89     const char* data() { return m_buffer.data(); }
     90     size_t size() const { return m_buffer.size(); }
     91     // Reset the inflate result.
     92     void reset();
     93 
     94 private:
     95     explicit WebSocketInflater(int windowBits);
     96 
     97     int m_windowBits;
     98     Vector<char> m_buffer;
     99     OwnPtr<z_stream> m_stream;
    100 };
    101 
    102 }
    103 
    104 #endif // WebSocketDeflater_h
    105