mstream.h

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/*
    This file is part of Mitsuba, a physically based rendering system.

    Copyright (c) 2007-2014 by Wenzel Jakob and others.

    Mitsuba is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License Version 3
    as published by the Free Software Foundation.

    Mitsuba 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 General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program. If not, see <http://www.gnu.org/licenses/>.
*/

#pragma once
#if !defined(__MITSUBA_CORE_MSTREAM_H_)
#define __MITSUBA_CORE_MSTREAM_H_

#include <mitsuba/mitsuba.h>

MTS_NAMESPACE_BEGIN

/** \brief Simple memory buffer-based stream with automatic memory management
 *
 * The underlying memory storage of this implementation dynamically expands
 * as data is written to the stream.
 *
 * \ingroup libcore
 * \ingroup libpython
 */
class MTS_EXPORT_CORE MemoryStream : public Stream {
public:
        // =============================================================
        //! @{ \name Constructors
        // =============================================================

        /// Create a new memory stream
        MemoryStream(size_t initialSize = 512);

        /**
         * \brief Create a memory stream, which operates on a
         * pre-allocated buffer.
         *
         * A memory stream created in this way will never resize the
         * underlying buffer. An exception is thrown e.g. when attempting
         * to extend its size
         *
         * \remark This constructor is not available in the python bindings
         */
        MemoryStream(void *ptr, size_t size);

        //! @}
        // =============================================================

        // =============================================================
        //! @{ \name Memory stream-specific features
        // =============================================================

        /// Return the underlying data
        inline uint8_t *getData() { return m_data; }

        /// Return the underlying data (const version)
        inline const uint8_t *getData() const { return m_data; }

        /// Return the underlying data at the current position
        inline uint8_t *getCurrentData() { return m_data + m_pos; }

        /// Return the underlying data at the current position (const version)
        inline const uint8_t *getCurrentData() const { return m_data + m_pos; }

        /// Set size and position to zero without changing the underlying buffer
        void reset();

        //! @}
        // =============================================================

        // =============================================================
        //! @{ \name Implementation of the Stream interface
        // =============================================================

        void read(void *ptr, size_t size);
        void write(const void *ptr, size_t size);
        void seek(size_t pos);
        size_t getPos() const;
        size_t getSize() const;
        void truncate(size_t size);
        void flush();
        bool canWrite() const;
        bool canRead() const;

        //! @}
        // =============================================================

        /// Return a string representation
        std::string toString() const;

        MTS_DECLARE_CLASS()
protected:
        void resize(size_t newSize);

        // \brief Virtual destructor
        virtual ~MemoryStream();
protected:
        size_t m_capacity;
        size_t m_size;
        size_t m_pos;
        bool m_ownsBuffer;
        uint8_t *m_data;
};

MTS_NAMESPACE_END

#endif /* __MITSUBA_CORE_MSTREAM_H_ */