circular_buffer.h

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/*
 * Copyright 2011 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http:///www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


#ifndef PAGESPEED_KERNEL_UTIL_CIRCULAR_BUFFER_H_
#define PAGESPEED_KERNEL_UTIL_CIRCULAR_BUFFER_H_

#include "pagespeed/kernel/base/basictypes.h"
#include "pagespeed/kernel/base/string.h"
#include "pagespeed/kernel/base/string_util.h"

namespace net_instaweb {

class MessageHandler;

class CircularBuffer {
 public:
  static CircularBuffer* Create(const int capacity);
  static CircularBuffer* Init(bool parent, void* block,
                              const int block_size,
                              const int capacity);
  static int Sizeof(const int capacity) {
    int total = sizeof(CircularBuffer) + capacity - 1;
    return total;
  }
  void Clear();
  bool Write(const StringPiece& message);
  GoogleString ToString(MessageHandler* handler);

 private:
  CircularBuffer();
  ~CircularBuffer();
  StringPiece FirstChunk();
  StringPiece SecondChunk();

  int capacity_;
  bool wrapped_;
  int offset_;
  char buffer_[1];

  
};

}  

#endif