CircularBuffer.h++

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/* ---------------------------------------------------------------------------
   commonc++ - A C++ Common Class Library
   Copyright (C) 2005-2014  Mark A Lindner

   This file is part of commonc++.

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License as published by the Free Software Foundation; either
   version 2 of the License, or (at your option) any later version.

   This library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with this library; if not, write to the Free
   Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   ---------------------------------------------------------------------------
*/

#ifndef __ccxx_CircularBuffer_hxx
#define __ccxx_CircularBuffer_hxx

#include <commonc++/Common.h++>
#include <commonc++/AbstractBuffer.h++>
#include <commonc++/IOException.h++>
#include <commonc++/MemoryBlock.h++>
#include <commonc++/Stream.h++>

#include <algorithm>
#include <cstdlib>
#include <cstring>

#ifdef CCXX_OS_POSIX
#include <sys/uio.h>
#endif

namespace ccxx {

template <typename T> class CircularBuffer : public AbstractBuffer<T>
{
 public:

  CircularBuffer(uint_t size);

  ~CircularBuffer();

  void clear();

  void setSize(uint_t newSize);

  uint_t write(const T* buf, uint_t count);

  uint_t write(Buffer<T>& buffer, uint_t count = 0);

  uint_t write(Stream& stream, uint_t count = 0);

  uint_t read(T* buf, uint_t count);

  uint_t read(Buffer<T>& buffer, uint_t count = 0);

  uint_t read(Stream& stream, uint_t count = 0);

  uint_t peek(const T& value, uint_t maxlen, bool& found,
              bool resetPeek = true);

  uint_t fill(const T& value, uint_t count);

  uint_t getReadExtent() const;

  uint_t getWriteExtent() const;

  inline uint_t getRemaining() const
  { return(_avail); }

  inline uint_t getPeekRemaining() const
  { return(_peekAvail); }

  inline bool isEmpty() const
  { return(_avail == 0); }

  inline bool isFull() const
  { return(this->_size == _avail); }

  inline uint_t getFree() const
  { return(this->_size - _avail); }

  inline T* getReadPos()
  { return(_readPos); }

  inline T* getWritePos()
  { return(_writePos); }

  inline T* getPeekPos()
  { return(_peekPos); }

  T* advanceReadPos(uint_t count);

  T* advanceWritePos(uint_t count);

  inline T* advanceReadPos()
  { return(advanceReadPos(getReadExtent())); }

  inline T* advanceWritePos()
  { return(advanceWritePos(getWriteExtent())); }

  T* advancePeekPos(uint_t count);

  void resetPeekPos();

  bool isPartialWrite() const
  { return(_writeShift > 0); }

  bool isPartialRead() const
  { return(_readShift > 0); }

  void markReadPos();

  void rewindReadPos();

  void markWritePos();

  void rewindWritePos();

  bool setReadPosFromMark(uint_t count);

  bool setWritePosFromMark(uint_t count);

 private:

  T* _end;
  T* _readPos;
  T* _writePos;
  T* _peekPos;
  T* _readMark;
  T* _writeMark;
  uint_t _avail;
  uint_t _peekAvail;
  uint_t _readShift;
  uint_t _writeShift;

  CCXX_COPY_DECLS(CircularBuffer);
};

#include <commonc++/CircularBufferImpl.h++>

typedef CircularBuffer<byte_t> CircularByteBuffer;
typedef CircularBuffer<char> CircularCharBuffer;

} // namespace ccxx

#endif // __ccxx_CircularBuffer_hxx