Page Speed Optimization Libraries  1.4.26.1
net/instaweb/util/public/circular_buffer.h
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00001 /*
00002  * Copyright 2011 Google Inc.
00003  *
00004  * Licensed under the Apache License, Version 2.0 (the "License");
00005  * you may not use this file except in compliance with the License.
00006  * You may obtain a copy of the License at
00007  *
00008  *      http:///www.apache.org/licenses/LICENSE-2.0
00009  *
00010  * Unless required by applicable law or agreed to in writing, software
00011  * distributed under the License is distributed on an "AS IS" BASIS,
00012  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  * See the License for the specific language governing permissions and
00014  * limitations under the License.
00015  */
00016 
00018 
00019 #ifndef NET_INSTAWEB_UTIL_PUBLIC_CIRCULAR_BUFFER_H_
00020 #define NET_INSTAWEB_UTIL_PUBLIC_CIRCULAR_BUFFER_H_
00021 
00022 #include "net/instaweb/util/public/basictypes.h"
00023 #include "net/instaweb/util/public/string.h"
00024 #include "net/instaweb/util/public/string_util.h"
00025 
00026 namespace net_instaweb {
00027 
00028 class MessageHandler;
00029 
00032 class CircularBuffer {
00033  public:
00035   static CircularBuffer* Create(const int capacity);
00043   static CircularBuffer* Init(bool parent, void* block,
00044                               const int block_size,
00045                               const int capacity);
00049   static int Sizeof(const int capacity) {
00051     int total = sizeof(CircularBuffer) + capacity - 1;
00052     return total;
00053   }
00056   void Clear();
00058   bool Write(const StringPiece& message);
00060   GoogleString ToString(MessageHandler* handler);
00061 
00062  private:
00065   CircularBuffer();
00066   ~CircularBuffer();
00068   StringPiece FirstChunk();
00070   StringPiece SecondChunk();
00071 
00073   int capacity_;
00075   bool wrapped_;
00077   int offset_;
00079   char buffer_[1];
00080 
00081   DISALLOW_COPY_AND_ASSIGN(CircularBuffer);
00082 };
00083 
00084 }  
00085 
00086 #endif  ///< NET_INSTAWEB_UTIL_PUBLIC_CIRCULAR_BUFFER_H_
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