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/*
Copyright (C) 2006 Paul Davis
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_midi_ring_buffer_h__
#define __ardour_midi_ring_buffer_h__
#include <algorithm>
#include <ardour/types.h>
#include <pbd/ringbufferNPT.h>
#include <ardour/buffer.h>
namespace ARDOUR {
/** A MIDI RingBuffer
* (necessary because MIDI events are variable sized so a generic RB won't do).
*
* ALL publically accessible sizes refer to event COUNTS. What actually goes
* on in here is none of the callers business :)
*/
class MidiRingBuffer {
public:
MidiRingBuffer (size_t size)
: _size(size)
, _max_event_size(MidiBuffer::max_event_size())
, _ev_buf(new MidiEvent[size])
, _raw_buf(new RawMidi[size * _max_event_size])
{
reset ();
assert(read_space() == 0);
assert(write_space() == size - 1);
}
virtual ~MidiRingBuffer() {
delete[] _ev_buf;
delete[] _raw_buf;
}
void reset () {
/* !!! NOT THREAD SAFE !!! */
g_atomic_int_set (&_write_ptr, 0);
g_atomic_int_set (&_read_ptr, 0);
}
size_t write_space () {
size_t w, r;
w = g_atomic_int_get (&_write_ptr);
r = g_atomic_int_get (&_read_ptr);
if (w > r) {
return ((r - w + _size) % _size) - 1;
} else if (w < r) {
return (r - w) - 1;
} else {
return _size - 1;
}
}
size_t read_space () {
size_t w, r;
w = g_atomic_int_get (&_write_ptr);
r = g_atomic_int_get (&_read_ptr);
if (w > r) {
return w - r;
} else {
return (w - r + _size) % _size;
}
}
size_t capacity() const { return _size; }
/** Read one event and appends it to @a out. */
//size_t read(MidiBuffer& out);
/** Write one event (@a in) */
size_t write(const MidiEvent& in); // deep copies in
/** Read events all events up to time @a end into @a out, leaving stamps intact.
* Any events before @a start will be dropped. */
size_t read(MidiBuffer& out, jack_nframes_t start, jack_nframes_t end);
/** Write all events from @a in, applying @a offset to all time stamps */
size_t write(const MidiBuffer& in, jack_nframes_t offset = 0);
inline void clear_event(size_t index);
private:
// _event_ indices
mutable gint _write_ptr;
mutable gint _read_ptr;
size_t _size; // size (capacity) in events
size_t _max_event_size; // ratio of raw_buf size to ev_buf size
MidiEvent* _ev_buf; // these point into...
RawMidi* _raw_buf; // this
};
/** Just for sanity checking */
inline void
MidiRingBuffer::clear_event(size_t index)
{
memset(&_ev_buf[index].buffer, 0, _max_event_size);
_ev_buf[index].time = 0;
_ev_buf[index].size = 0;
_ev_buf[index].buffer = 0;
}
inline size_t
MidiRingBuffer::write (const MidiEvent& ev)
{
//static jack_nframes_t last_write_time = 0;
assert(ev.size > 0);
size_t priv_write_ptr = g_atomic_int_get(&_write_ptr);
if (write_space () == 0) {
return 0;
} else {
//assert(ev.time >= last_write_time);
const size_t raw_index = priv_write_ptr * _max_event_size;
MidiEvent* const write_ev = &_ev_buf[priv_write_ptr];
*write_ev = ev;
memcpy(&_raw_buf[raw_index], ev.buffer, ev.size);
write_ev->buffer = &_raw_buf[raw_index];
g_atomic_int_set(&_write_ptr, (priv_write_ptr + 1) % _size);
//printf("MRB - wrote %xd %d %d with time %u at index %zu (raw index %zu)\n",
// write_ev->buffer[0], write_ev->buffer[1], write_ev->buffer[2], write_ev->time,
// priv_write_ptr, raw_index);
assert(write_ev->size = ev.size);
//last_write_time = ev.time;
//printf("(W) read space: %zu\n", read_space());
return 1;
}
}
inline size_t
MidiRingBuffer::read(MidiBuffer& dst, jack_nframes_t start, jack_nframes_t end)
{
if (read_space() == 0)
return 0;
size_t priv_read_ptr = g_atomic_int_get(&_read_ptr);
jack_nframes_t time = _ev_buf[priv_read_ptr].time;
size_t count = 0;
size_t limit = read_space();
while (time <= end && limit > 0) {
MidiEvent* const read_ev = &_ev_buf[priv_read_ptr];
if (time >= start) {
dst.push_back(*read_ev);
//printf("MRB - read %#X %d %d with time %u at index %zu\n",
// read_ev->buffer[0], read_ev->buffer[1], read_ev->buffer[2], read_ev->time,
// priv_read_ptr);
} else {
printf("MRB - SKIPPING - %#X %d %d with time %u at index %zu\n",
read_ev->buffer[0], read_ev->buffer[1], read_ev->buffer[2], read_ev->time,
priv_read_ptr);
break;
}
clear_event(priv_read_ptr);
++count;
--limit;
priv_read_ptr = (priv_read_ptr + 1) % _size;
assert(read_ev->time <= end);
time = _ev_buf[priv_read_ptr].time;
}
g_atomic_int_set(&_read_ptr, priv_read_ptr);
//printf("(R) read space: %zu\n", read_space());
return count;
}
inline size_t
MidiRingBuffer::write(const MidiBuffer& in, jack_nframes_t offset)
{
size_t num_events = in.size();
size_t to_write = std::min(write_space(), num_events);
// FIXME: double copy :/
for (size_t i=0; i < to_write; ++i) {
MidiEvent ev = in[i];
ev.time += offset;
write(ev);
}
return to_write;
}
} // namespace ARDOUR
#endif // __ardour_midi_ring_buffer_h__
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