2 Copyright (C) 2006 Paul Davis
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software
16 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 #ifndef __ardour_midi_ring_buffer_h__
20 #define __ardour_midi_ring_buffer_h__
24 #include <ardour/types.h>
25 #include <ardour/buffer.h>
26 #include <ardour/event_type_map.h>
27 #include <evoral/EventSink.hpp>
28 #include <evoral/EventRingBuffer.hpp>
33 /** A RingBuffer for (MIDI) events.
35 * This is simply a wrapper around a raw ringbuffer which writes/reads events
36 * as flat placked blobs.
37 * The buffer looks like this:
39 * [timestamp][type][size][size bytes of raw MIDI][timestamp][type][size](etc...)
41 class MidiRingBuffer : public Evoral::EventRingBuffer {
43 /** @param size Size in bytes.
45 MidiRingBuffer(size_t size)
46 : Evoral::EventRingBuffer(size)
47 , _channel_mask(0x0000FFFF)
50 inline bool read_prefix(Evoral::EventTime* time, Evoral::EventType* type, uint32_t* size);
51 inline bool read_contents(uint32_t size, uint8_t* buf);
53 size_t read(MidiBuffer& dst, nframes_t start, nframes_t end, nframes_t offset=0);
55 /** Set the channel filtering mode.
56 * @param mask If mode is FilterChannels, each bit represents a midi channel:
57 * bit 0 = channel 0, bit 1 = channel 1 etc. the read and write methods will only
58 * process events whose channel bit is 1.
59 * If mode is ForceChannel, mask is simply a channel number which all events will
60 * be forced to while reading.
62 void set_channel_mode(ChannelMode mode, uint16_t mask) {
63 g_atomic_int_set(&_channel_mask, ((uint16_t)mode << 16) | mask);
66 ChannelMode get_channel_mode() const {
67 return static_cast<ChannelMode>((g_atomic_int_get(&_channel_mask) & 0xFFFF0000) >> 16);
70 uint16_t get_channel_mask() const {
71 return static_cast<ChannelMode>((g_atomic_int_get(&_channel_mask) & 0x0000FFFF));
75 inline bool is_channel_event(uint8_t event_type_byte) {
76 // mask out channel information
77 event_type_byte &= 0xF0;
78 // midi channel events range from 0x80 to 0xE0
79 return (0x80 <= event_type_byte) && (event_type_byte <= 0xE0);
83 volatile uint32_t _channel_mask; // 16 bits mode, 16 bits mask
87 /** Read the time and size of an event. This call MUST be immediately proceeded
88 * by a call to read_contents (or the read pointer will be garbage).
91 MidiRingBuffer::read_prefix(Evoral::EventTime* time, Evoral::EventType* type, uint32_t* size)
93 bool success = Evoral::EventRingBuffer::full_read(sizeof(Evoral::EventTime), (uint8_t*)time);
95 success = Evoral::EventRingBuffer::full_read(sizeof(Evoral::EventType), (uint8_t*)type);
97 success = Evoral::EventRingBuffer::full_read(sizeof(uint32_t), (uint8_t*)size);
103 /** Read the content of an event. This call MUST be immediately preceded
104 * by a call to read_prefix (or the returned even will be garbage).
107 MidiRingBuffer::read_contents(uint32_t size, uint8_t* buf)
109 return Evoral::EventRingBuffer::full_read(size, buf);
113 /** Read a block of MIDI events from buffer.
115 * Timestamps of events returned are relative to start (i.e. event with stamp 0
116 * occurred at start), with offset added.
119 MidiRingBuffer::read(MidiBuffer& dst, nframes_t start, nframes_t end, nframes_t offset)
121 if (read_space() == 0) {
122 //std::cerr << "MRB: NO READ SPACE" << std::endl;
126 Evoral::EventTime ev_time;
127 Evoral::EventType ev_type;
132 //std::cerr << "MRB read " << start << " .. " << end << " + " << offset << std::endl;
134 while (read_space() >= sizeof(Evoral::EventTime) + sizeof(Evoral::EventType) + sizeof(uint32_t)) {
136 full_peek(sizeof(Evoral::EventTime), (uint8_t*)&ev_time);
139 //std::cerr << "MRB: PAST END (" << ev_time << " : " << end << ")" << std::endl;
141 } else if (ev_time < start) {
142 //std::cerr << "MRB (start " << start << ") - Skipping event at (too early) time " << ev_time << std::endl;
146 bool success = read_prefix(&ev_time, &ev_type, &ev_size);
148 std::cerr << "WARNING: error reading event prefix from MIDI ring" << std::endl;
152 // This event marks a loop happening. this means that
153 // the next events timestamp will be non-monotonic.
154 if (ev_type == LoopEventType) {
157 Evoral::MIDIEvent loopevent(LoopEventType, ev_time);
158 dst.push_back(loopevent);
161 // We can safely return, without reading the data, because
162 // a LoopEvent does not have data.
167 success = full_peek(sizeof(uint8_t), &status);
168 assert(success); // If this failed, buffer is corrupt, all hope is lost
170 // Ignore event if it doesn't match channel filter
171 if (is_channel_event(status) && get_channel_mode() == FilterChannels) {
172 const uint8_t channel = status & 0x0F;
173 if ( !(get_channel_mask() & (1L << channel)) ) {
174 //std::cerr << "MRB skipping event due to channel mask" << std::endl;
175 skip(ev_size); // Advance read pointer to next event
180 //std::cerr << "MRB " << this << " - Reading event, time = "
181 // << ev_time << " - " << start << " => " << ev_time - start
182 // << ", size = " << ev_size << std::endl;
184 assert(ev_time >= start);
188 uint8_t* write_loc = dst.reserve(ev_time, ev_size);
189 if (write_loc == NULL) {
190 //std::cerr << "MRB: Unable to reserve space in buffer, event skipped";
194 success = Evoral::EventRingBuffer::full_read(ev_size, write_loc);
197 if (is_channel_event(status) && get_channel_mode() == ForceChannel) {
198 write_loc[0] = (write_loc[0] & 0xF0) | (get_channel_mask() & 0x0F);
201 //std::cerr << "MRB - read event at time " << ev_time << std::endl;
203 std::cerr << "WARNING: error reading event contents from MIDI ring" << std::endl;
207 //std::cerr << "MTB read space: " << read_space() << std::endl;
213 } // namespace ARDOUR
215 #endif // __ardour_midi_ring_buffer_h__