Refactor ZLib and Verbatim encoders.

remoting/base/compressor.h

 // 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.
 
 #ifndef REMOTING_BASE_COMPRESSOR_H_
 #define REMOTING_BASE_COMPRESSOR_H_
 
 #include "base/basictypes.h"
 
 namespace remoting {
 
 // An object to compress data losslessly. Compressed data can be fully
 // recovered by a Decompressor.
 //
 // Note that a Compressor can only be used on one stream during its
 // lifetime. This object should be destroyed after use.
 class Compressor {
  public:
 
   // Defines the flush modes for a compressor.
   enum CompressorFlush {
     CompressorNoFlush,
     CompressorSyncFlush,
     CompressorFinish,
   };
   virtual ~Compressor() {}
 
+  // Resets all the internal state so the compressor behaves as if it
+  // was just created.
+  virtual void Reset() = 0;
+
   // Compress |input_data| with |input_size| bytes.
   //
   // |output_data| is provided by the caller and |output_size| is the
   // size of |output_data|. |output_size| must be greater than 0.
   //
   // |flush| is set to one of the three value:
   // - CompressorNoFlush
   //   No flushing is requested
   // - CompressorSyncFlush
   //   Write all pending output and write a synchronization point in the
   //   output data stream.
   // - CompressorFinish
   //   Mark the end of stream.
   //
   // Compressed data is written to |output_data|. |consumed| will
   // contain the number of bytes consumed from the input. |written|
   // contains the number of bytes written to output.
   //
   // Returns true if this method needs to be called again because
   // there is more data to be written out. This is particularly
   // useful for end of the compression stream.
   virtual bool Process(const uint8* input_data, int input_size,
                        uint8* output_data, int output_size,
                        CompressorFlush flush, int* consumed, int* written) = 0;
 };
 
 }  // namespace remoting
 
 #endif  // REMOTING_BASE_COMPRESSOR_H_