/*
 * Copyright 2009-2014, Haiku, Inc. All Rights Reserved.
 * Distributed under the terms of the MIT License.
 *
 * Authors:
 *              Bruno Albuquerque, bga@bug-br.org.br
 */

#ifndef _DYNAMIC_BUFFER_H
#define _DYNAMIC_BUFFER_H

#include <DataIO.h>
#include <SupportDefs.h>


class DynamicBuffer : public BDataIO {
public:
        DynamicBuffer(size_t initialSize = 0);
        ~DynamicBuffer();

        DynamicBuffer(const DynamicBuffer& buffer);
        
        // InitCheck() should be called to guarantee the object initialization
        // didn't fail. If it does not return B_OK, the initialization failed.
        status_t InitCheck() const;
        
        // Insert data at the end of the buffer. The buffer will be increased to
        // accomodate the data if needed.
        virtual ssize_t Write(const void* data, size_t size);
        
        // Remove data from the start of the buffer. Move the buffer start
        // pointer to point to the data following it.
        virtual ssize_t Read(void* data, size_t size);

        // Return a pointer to the underlying buffer. Note this will not
        // necessarily be a pointer to the start of the allocated memory as the
        // initial data may be positioned at an offset inside the buffer. In other
        // words, this returns a pointer to the start of data inside the buffer.
        unsigned char* Data() const;
        
        // Returns the actual buffer size. This is the amount of memory allocated
        // for the buffer.
        size_t Size() const;
        
        // Number of bytes of data still present in the buffer that can be
        // extracted through calls to Remove().
        size_t BytesRemaining() const;

        // Dump some buffer statistics to stdout.
        void PrintToStream();

private:
        status_t _GrowToFit(size_t size, bool exact = false);
        
        unsigned char* fBuffer;
        size_t fBufferSize;
        size_t fDataStart;
        size_t fDataEnd;
        
        status_t fInit;
};

#endif  // _DYNAMIC_BUFFER_H