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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 <iostream>
#include <algorithm>
#include <ardour/types.h>
#include <ardour/buffer.h>
#include <ardour/event_type_map.h>
#include <evoral/EventSink.hpp>
#include <evoral/EventRingBuffer.hpp>
namespace ARDOUR {
/** A RingBuffer for (MIDI) events.
*
* This is simply a wrapper around a raw ringbuffer which writes/reads events
* as flat placked blobs.
* The buffer looks like this:
*
* [timestamp][type][size][size bytes of raw MIDI][timestamp][type][size](etc...)
*/
class MidiRingBuffer : public Evoral::EventRingBuffer {
public:
/** @param size Size in bytes.
*/
MidiRingBuffer(size_t size)
: Evoral::EventRingBuffer(size)
, _channel_mask(0x0000FFFF)
{}
inline bool read_prefix(EventTime* time, EventType* type, uint32_t* size);
inline bool read_contents(uint32_t size, uint8_t* buf);
size_t read(MidiBuffer& dst, nframes_t start, nframes_t end, nframes_t offset=0);
/** Set the channel filtering mode.
* @param mask If mode is FilterChannels, each bit represents a midi channel:
* bit 0 = channel 0, bit 1 = channel 1 etc. the read and write methods will only
* process events whose channel bit is 1.
* If mode is ForceChannel, mask is simply a channel number which all events will
* be forced to while reading.
*/
void set_channel_mode(ChannelMode mode, uint16_t mask) {
g_atomic_int_set(&_channel_mask, ((uint16_t)mode << 16) | mask);
}
ChannelMode get_channel_mode() const {
return static_cast<ChannelMode>((g_atomic_int_get(&_channel_mask) & 0xFFFF0000) >> 16);
}
uint16_t get_channel_mask() const {
return static_cast<ChannelMode>((g_atomic_int_get(&_channel_mask) & 0x0000FFFF));
}
protected:
inline bool is_channel_event(uint8_t event_type_byte) {
// mask out channel information
event_type_byte &= 0xF0;
// midi channel events range from 0x80 to 0xE0
return (0x80 <= event_type_byte) && (event_type_byte <= 0xE0);
}
private:
volatile uint32_t _channel_mask; // 16 bits mode, 16 bits mask
};
/** Read the time and size of an event. This call MUST be immediately proceeded
* by a call to read_contents (or the read pointer will be garabage).
*/
inline bool
MidiRingBuffer::read_prefix(EventTime* time, EventType* type, uint32_t* size)
{
bool success = Evoral::EventRingBuffer::full_read(sizeof(EventTime), (uint8_t*)time);
if (success)
success = Evoral::EventRingBuffer::full_read(sizeof(EventType), (uint8_t*)type);
if (success)
success = Evoral::EventRingBuffer::full_read(sizeof(uint32_t), (uint8_t*)size);
return success;
}
/** Read the contenst of an event. This call MUST be immediately preceeded
* by a call to read_prefix (or the returned even will be garabage).
*/
inline bool
MidiRingBuffer::read_contents(uint32_t size, uint8_t* buf)
{
return Evoral::EventRingBuffer::full_read(size, buf);
}
/** Read a block of MIDI events from buffer.
*
* Timestamps of events returned are relative to start (ie event with stamp 0
* occurred at start), with offset added.
*/
inline size_t
MidiRingBuffer::read(MidiBuffer& dst, nframes_t start, nframes_t end, nframes_t offset)
{
if (read_space() == 0) {
//std::cerr << "MRB: NO READ SPACE" << std::endl;
return 0;
}
EventTime ev_time;
EventType ev_type;
uint32_t ev_size;
size_t count = 0;
//std::cerr << "MRB read " << start << " .. " << end << " + " << offset << std::endl;
while (read_space() > sizeof(EventTime) + sizeof(EventType) + sizeof(uint32_t)) {
full_peek(sizeof(EventTime), (uint8_t*)&ev_time);
if (ev_time > end) {
//std::cerr << "MRB: PAST END (" << ev_time << " : " << end << ")" << std::endl;
break;
} else if (ev_time < start) {
//std::cerr << "MRB (start " << start << ") - Skipping event at (too early) time " << ev_time << std::endl;
break;
}
bool success = read_prefix(&ev_time, &ev_type, &ev_size);
if (!success) {
std::cerr << "WARNING: error reading event prefix from MIDI ring" << std::endl;
continue;
}
// This event marks a loop happening. this means that
// the next events timestamp will be non-monotonic.
if (ev_type == LoopEventType) {
ev_time -= start;
Evoral::MIDIEvent loopevent(LoopEventType, ev_time);
dst.push_back(loopevent);
// We can safely return, without reading the data, because
// a LoopEvent does not have data.
return count + 1;
}
uint8_t status;
success = full_peek(sizeof(uint8_t), &status);
assert(success); // If this failed, buffer is corrupt, all hope is lost
// Ignore event if it doesn't match channel filter
if (is_channel_event(status) && get_channel_mode() == FilterChannels) {
const uint8_t channel = status & 0x0F;
if ( !(get_channel_mask() & (1L << channel)) ) {
//std::cerr << "MRB skipping event due to channel mask" << std::endl;
skip(ev_size); // Advance read pointer to next event
continue;
}
}
//std::cerr << "MRB " << this << " - Reading event, time = "
// << ev_time << " - " << start << " => " << ev_time - start
// << ", size = " << ev_size << std::endl;
assert(ev_time >= start);
ev_time -= start;
ev_time += offset;
uint8_t* write_loc = dst.reserve(ev_time, ev_size);
if (write_loc == NULL) {
//std::cerr << "MRB: Unable to reserve space in buffer, event skipped";
continue;
}
success = Evoral::EventRingBuffer::full_read(ev_size, write_loc);
if (success) {
if (is_channel_event(status) && get_channel_mode() == ForceChannel) {
write_loc[0] = (write_loc[0] & 0xF0) | (get_channel_mask() & 0x0F);
}
++count;
//std::cerr << "MRB - read event at time " << ev_time << std::endl;
} else {
std::cerr << "WARNING: error reading event contents from MIDI ring" << std::endl;
}
}
//std::cerr << "MTB read space: " << read_space() << std::endl;
return count;
}
} // namespace ARDOUR
#endif // __ardour_midi_ring_buffer_h__
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