Jack2: JackMidiPort.cpp Source File

Jack2 1.9.12

JackMidiPort.cpp
1 /*
2 Copyright (C) 2007 Dmitry Baikov
3 Original JACK MIDI implementation Copyright (C) 2004 Ian Esten
4
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU Lesser General Public License as published by
7 the Free Software Foundation; either version 2.1 of the License, or
8 (at your option) any later version.
9
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public License
16 along with this program; if not, write to the Free Software
17 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18
19 */
20
21 #include "JackError.h"
22 #include "JackPortType.h"
23 #include "JackMidiPort.h"
24 #include <assert.h>
25 #include <string.h>
26
27 namespace Jack
28 {
29
30 SERVER_EXPORT void JackMidiBuffer::Reset(jack_nframes_t nframes)
31 {
32 /* This line ate 1 hour of my life... dsbaikov */
33 this->nframes = nframes;
34 write_pos = 0;
35 event_count = 0;
36 lost_events = 0;
37 }
38
39 SERVER_EXPORT jack_shmsize_t JackMidiBuffer::MaxEventSize() const
40 {
41 assert (((jack_shmsize_t) - 1) < 0); // jack_shmsize_t should be signed
42 jack_shmsize_t left = buffer_size - (sizeof(JackMidiBuffer) + sizeof(JackMidiEvent) * (event_count + 1) + write_pos);
43 if (left < 0) {
44 return 0;
45 }
46 if (left <= JackMidiEvent::INLINE_SIZE_MAX) {
47 return JackMidiEvent::INLINE_SIZE_MAX;
48 }
49 return left;
50 }
51
52 SERVER_EXPORT jack_midi_data_t* JackMidiBuffer::ReserveEvent(jack_nframes_t time, jack_shmsize_t size)
53 {
54 jack_shmsize_t space = MaxEventSize();
55 if (space == 0 || size > space) {
56 jack_error("JackMidiBuffer::ReserveEvent - the buffer does not have "
57 "enough room to enqueue a %lu byte event", size);
58 lost_events++;
59 return 0;
60 }
61 JackMidiEvent* event = &events[event_count++];
62 event->time = time;
63 event->size = size;
64
65 if (size <= JackMidiEvent::INLINE_SIZE_MAX) {
66 return event->data;
67 }
68
69 write_pos += size;
70 event->offset = buffer_size - write_pos;
71 return (jack_midi_data_t*)this + event->offset;
72 }
73
74 void MidiBufferInit(void* buffer, size_t buffer_size, jack_nframes_t nframes)
75 {
76 JackMidiBuffer* midi = (JackMidiBuffer*)buffer;
77 midi->magic = JackMidiBuffer::MAGIC;
78 /* Since port buffer has actually always BUFFER_SIZE_MAX frames, we can safely use all the size */
79 midi->buffer_size = BUFFER_SIZE_MAX * sizeof(jack_default_audio_sample_t);
80 midi->Reset(nframes);
81 }
82
83 /*
84 * The mixdown function below, is a simplest (read slowest) implementation possible.
85 * But, since it is unlikely that it will mix many buffers with many events,
86 * it should perform quite good.
87 * More efficient (and possibly, fastest possible) implementation (it exists),
88 * using calendar queue algorithm is about 3 times bigger, and uses alloca().
89 * So, let's listen to D.Knuth about premature optimisation, a leave the current
90 * implementation as is, until it is proved to be a bottleneck.
91 * Dmitry Baikov.
92 */
93 static void MidiBufferMixdown(void* mixbuffer, void** src_buffers, int src_count, jack_nframes_t nframes)
94 {
95 JackMidiBuffer* mix = static_cast<JackMidiBuffer*>(mixbuffer);
96 if (!mix->IsValid()) {
97 jack_error("Jack::MidiBufferMixdown - invalid mix buffer");
98 return;
99 }
100 mix->Reset(nframes);
101
102 uint32_t mix_index[src_count];
103 int event_count = 0;
104 for (int i = 0; i < src_count; ++i) {
105 JackMidiBuffer* buf = static_cast<JackMidiBuffer*>(src_buffers[i]);
106 if (!buf->IsValid()) {
107 jack_error("Jack::MidiBufferMixdown - invalid source buffer");
108 return;
109 }
110 mix_index[i] = 0;
111 event_count += buf->event_count;
112 mix->lost_events += buf->lost_events;
113 }
114
115 int events_done;
116 for (events_done = 0; events_done < event_count; ++events_done) {
117 JackMidiBuffer* next_buf = 0;
118 JackMidiEvent* next_event = 0;
119 uint32_t next_buf_index = 0;
120
121 // find the earliest event
122 for (int i = 0; i < src_count; ++i) {
123 JackMidiBuffer* buf = static_cast<JackMidiBuffer*>(src_buffers[i]);
124 if (mix_index[i] >= buf->event_count)
125 continue;
126 JackMidiEvent* e = &buf->events[mix_index[i]];
127 if (!next_event || e->time < next_event->time) {
128 next_event = e;
129 next_buf = buf;
130 next_buf_index = i;
131 }
132 }
133 assert(next_event != 0);
134
135 // write the event
136 jack_midi_data_t* dest = mix->ReserveEvent(next_event->time, next_event->size);
137 if (!dest) break;
138
139 memcpy(dest, next_event->GetData(next_buf), next_event->size);
140 mix_index[next_buf_index]++;
141 }
142 mix->lost_events += event_count - events_done;
143 }
144
145 static size_t MidiBufferSize()
146 {
147 return BUFFER_SIZE_MAX * sizeof(jack_default_audio_sample_t);
148 }
149
150 const JackPortType gMidiPortType =
151 {
152 JACK_DEFAULT_MIDI_TYPE,
153 MidiBufferSize,
154 MidiBufferInit,
155 MidiBufferMixdown
156 };
157
158 } // namespace Jack
jack_error
SERVER_EXPORT void jack_error(const char *fmt,...)
Definition: JackError.cpp:92
Jack::JackMidiBuffer::write_pos
jack_shmsize_t write_pos
data write position from the end of the buffer.
Definition: JackMidiPort.h:82