IOStack.h

/*
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 *
 * IOStack.h
 * A non-contigous memory buffer that operates as a stack (LIFO).
 * Copyright (C) 2013 Simon Newton
 */

#ifndef INCLUDE_OLA_IO_IOSTACK_H_
#define INCLUDE_OLA_IO_IOSTACK_H_

#include <ola/base/Macro.h>
#include <ola/io/IOVecInterface.h>
#include <ola/io/InputBuffer.h>
#include <ola/io/OutputBuffer.h>
#include <stdint.h>
#include <deque>
#include <iostream>
#include <queue>
#include <string>

namespace ola {
namespace io {

class IOStack: public IOVecInterface,
 public InputBufferInterface,
 public OutputBufferInterface {
 public:
 IOStack();
 explicit IOStack(class MemoryBlockPool *block_pool);

 ~IOStack();

 unsigned int Size() const;

 bool Empty() const {
 // guard against the case of Empty blocks.
 return m_blocks.empty() || Size() == 0;
 }

 // From OutputBufferInterface
 void Write(const uint8_t *data, unsigned int length);

 // From InputBufferInterface, these reads consume data from the buffer.
 unsigned int Read(uint8_t *data, unsigned int length);
 unsigned int Read(std::string *output, unsigned int length);

 // From IOVecInterface
 const struct IOVec *AsIOVec(int *io_count) const;
 void Pop(unsigned int n);

 // 0-copy append to an IOQueue
 void MoveToIOQueue(class IOQueue *queue);

 // purge the underlying memory pool
 void Purge();

 void Dump(std::ostream *output);

 private:
 typedef std::deque<class MemoryBlock*> BlockVector;

 class MemoryBlockPool* m_pool;
 bool m_delete_pool;

 BlockVector m_blocks;

 void PrependBlock();

 // no copying / assignment for now
 DISALLOW_COPY_AND_ASSIGN(IOStack);
};
} // namespace io
} // namespace ola
#endif // INCLUDE_OLA_IO_IOSTACK_H_