event_ring_buffer.h

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/*
 * Copyright (C) 2014 David Robillard <d@drobilla.net>
 *
 * 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.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
 
#pragma once
 
#include <algorithm>
#include <cassert>
#include <iostream>
 
#include "pbd/ringbufferNPT.h"
 
#include "evoral/EventSink.h"
#include "evoral/types.h"
 
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;
        }
 
        assert (vec.len[0] > 0 || vec.len[1] > 0);
 
        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)
{
        assert (size > 0);
        if (!buf || size == 0 || 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