event_ring_buffer.h

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/*
    Copyright (C) 2006-2014 Paul Davis
    Author: David Robillard

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

    This program 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, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#ifndef __ardour_event_ring_buffer_h__
#define __ardour_event_ring_buffer_h__

#include <algorithm>
#include <iostream>

#include "pbd/ringbufferNPT.h"

#include "evoral/EventSink.hpp"
#include "evoral/types.hpp"

namespace ARDOUR {

template<typename Time>
class EventRingBuffer : public PBD::RingBufferNPT<uint8_t>
                      , public Evoral::EventSink<Time> {
public:

        EventRingBuffer(size_t capacity) : PBD::RingBufferNPT<uint8_t>(capacity)
        {}

        inline size_t capacity() const { return bufsize(); }

        inline bool peek (uint8_t*, size_t size);

        inline uint32_t write(Time  time, Evoral::EventType  type, uint32_t  size, const uint8_t* buf);
        inline bool     read (Time* time, Evoral::EventType* type, uint32_t* size,       uint8_t* buf);
};

template<typename Time>
inline bool
EventRingBuffer<Time>::peek (uint8_t* buf, size_t size)
{
        PBD::RingBufferNPT<uint8_t>::rw_vector vec;

        get_read_vector (&vec);

        if (vec.len[0] + vec.len[1] < size) {
                return false;
        }

        if (vec.len[0] > 0) {
                memcpy (buf, vec.buf[0], std::min (vec.len[0], size));
        }

        if (vec.len[0] < size) {
                if (vec.len[1]) {
                        memcpy (buf + vec.len[0], vec.buf[1], size - vec.len[0]);
                }
        }

        return true;
}

template<typename Time>
inline bool
EventRingBuffer<Time>::read(Time* time, Evoral::EventType* type, uint32_t* size, uint8_t* buf)
{
        if (PBD::RingBufferNPT<uint8_t>::read ((uint8_t*)time, sizeof (Time)) != sizeof (Time)) {
                return false;
        }

        if (PBD::RingBufferNPT<uint8_t>::read ((uint8_t*)type, sizeof(Evoral::EventType)) != sizeof (Evoral::EventType)) {
                return false;
        }

        if (PBD::RingBufferNPT<uint8_t>::read ((uint8_t*)size, sizeof(uint32_t)) != sizeof (uint32_t)) {
                return false;
        }

        if (PBD::RingBufferNPT<uint8_t>::read (buf, *size) != *size) {
                return false;
        }

        return true;
}

template<typename Time>
inline uint32_t
EventRingBuffer<Time>::write(Time time, Evoral::EventType type, uint32_t size, const uint8_t* buf)
{
        if (!buf || write_space() < (sizeof(Time) + sizeof(Evoral::EventType) + sizeof(uint32_t) + size)) {
                return 0;
        } else {
                PBD::RingBufferNPT<uint8_t>::write ((uint8_t*)&time, sizeof(Time));
                PBD::RingBufferNPT<uint8_t>::write ((uint8_t*)&type, sizeof(Evoral::EventType));
                PBD::RingBufferNPT<uint8_t>::write ((uint8_t*)&size, sizeof(uint32_t));
                PBD::RingBufferNPT<uint8_t>::write (buf, size);
                return size;
        }
}

} // namespace ARDOUR

#endif // __ardour_event_ring_buffer_h__