ardour/libs/ardour/ardour/event_ring_buffer.h

136 lines
3.9 KiB
C++

/*
* 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.
*/
#ifndef __ardour_event_ring_buffer_h__
#define __ardour_event_ring_buffer_h__
#include <algorithm>
#include <iostream>
#include "pbd/ringbufferNPT.h"
#include "evoral/EventSink.h"
#include "evoral/types.h"
namespace ARDOUR {
/** A RingBuffer of events (generic time-stamped binary "blobs").
*
* This packs a timestamp, size, and size bytes of data flat into the buffer.
* Useful for MIDI events, OSC messages, etc.
*
* Note: the uint8_t template argument to RingBufferNPT<> indicates "byte
* oriented data", not anything particular linked to MIDI or any other
* possible interpretation of uint8_t.
*/
template<typename Time>
class EventRingBuffer : public PBD::RingBufferNPT<uint8_t>
, public Evoral::EventSink<Time> {
public:
/** @param capacity Ringbuffer capacity in bytes.
*/
EventRingBuffer(size_t capacity) : PBD::RingBufferNPT<uint8_t>(capacity)
{}
inline size_t capacity() const { return bufsize(); }
/** Peek at the ringbuffer (read w/o advancing read pointer).
* @return how much has been peeked (wraps around if read exceeds
* the end of the buffer):
* <pre>
* |===========--------------R=============================|
* read-pointer---^
* </pre>
*/
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
#endif // __ardour_event_ring_buffer_h__