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>
30 /* FIXME: this is probably too much inlined code */
34 * Read/Write realtime safe.
35 * Single-reader Single-writer thread safe.
37 * This is Raul::RingBuffer, lifted for MIDIRingBuffer to inherit from as it works
38 * a bit differently than PBD::Ringbuffer. This could/should be replaced with
39 * the PBD ringbuffer to decrease code size, but this code is tested and known to
40 * work, so here it sits for now...
42 * Ignore this class, use MidiRingBuffer.
45 class MidiRingBufferBase {
48 /** @param size Size in bytes.
50 MidiRingBufferBase(size_t size)
55 assert(read_space() == 0);
56 assert(write_space() == size - 1);
59 virtual ~MidiRingBufferBase() {
63 /** Reset(empty) the ringbuffer.
67 g_atomic_int_set(&_write_ptr, 0);
68 g_atomic_int_set(&_read_ptr, 0);
71 size_t write_space() const {
73 const size_t w = g_atomic_int_get(&_write_ptr);
74 const size_t r = g_atomic_int_get(&_read_ptr);
77 return ((r - w + _size) % _size) - 1;
85 size_t read_space() const {
87 const size_t w = g_atomic_int_get(&_write_ptr);
88 const size_t r = g_atomic_int_get(&_read_ptr);
93 return (w - r + _size) % _size;
97 size_t capacity() const { return _size; }
99 size_t peek(size_t size, T* dst);
100 bool full_peek(size_t size, T* dst);
102 size_t read(size_t size, T* dst);
103 bool full_read(size_t size, T* dst);
105 void write(size_t size, const T* src);
108 mutable gint _write_ptr;
109 mutable gint _read_ptr;
111 size_t _size; ///< Size (capacity) in bytes
112 T* _buf; ///< size, event, size, event...
116 /** Peek at the ringbuffer (read w/o advancing read pointer).
118 * Note that a full read may not be done if the data wraps around.
119 * Caller must check return value and call again if necessary, or use the
120 * full_peek method which does this automatically.
124 MidiRingBufferBase<T>::peek(size_t size, T* dst)
126 const size_t priv_read_ptr = g_atomic_int_get(&_read_ptr);
128 const size_t read_size = (priv_read_ptr + size < _size)
130 : _size - priv_read_ptr;
132 memcpy(dst, &_buf[priv_read_ptr], read_size);
140 MidiRingBufferBase<T>::full_peek(size_t size, T* dst)
142 if (read_space() < size)
145 const size_t read_size = peek(size, dst);
147 if (read_size < size)
148 peek(size - read_size, dst + read_size);
154 /** Read from the ringbuffer.
156 * Note that a full read may not be done if the data wraps around.
157 * Caller must check return value and call again if necessary, or use the
158 * full_read method which does this automatically.
162 MidiRingBufferBase<T>::read(size_t size, T* dst)
164 const size_t priv_read_ptr = g_atomic_int_get(&_read_ptr);
166 const size_t read_size = (priv_read_ptr + size < _size)
168 : _size - priv_read_ptr;
170 memcpy(dst, &_buf[priv_read_ptr], read_size);
172 g_atomic_int_set(&_read_ptr, (priv_read_ptr + read_size) % _size);
180 MidiRingBufferBase<T>::full_read(size_t size, T* dst)
182 if (read_space() < size)
185 const size_t read_size = read(size, dst);
187 if (read_size < size)
188 read(size - read_size, dst + read_size);
196 MidiRingBufferBase<T>::write(size_t size, const T* src)
198 const size_t priv_write_ptr = g_atomic_int_get(&_write_ptr);
200 if (priv_write_ptr + size <= _size) {
201 memcpy(&_buf[priv_write_ptr], src, size);
202 g_atomic_int_set(&_write_ptr, (priv_write_ptr + size) % _size);
204 const size_t this_size = _size - priv_write_ptr;
205 assert(this_size < size);
206 assert(priv_write_ptr + this_size <= _size);
207 memcpy(&_buf[priv_write_ptr], src, this_size);
208 memcpy(&_buf[0], src+this_size, size - this_size);
209 g_atomic_int_set(&_write_ptr, size - this_size);
214 /* ******************************************************************** */
217 /** A MIDI RingBuffer.
219 * This is timestamps and MIDI packed sequentially into a single buffer, similarly
220 * to LV2 MIDI. The buffer looks like this:
222 * [timestamp][size][size bytes of raw MIDI][timestamp][size][etc..]
224 class MidiRingBuffer : public MidiRingBufferBase<Byte> {
227 /** @param size Size in bytes.
229 MidiRingBuffer(size_t size)
230 : MidiRingBufferBase<Byte>(size)
233 size_t write(double time, size_t size, const Byte* buf);
234 bool read(double* time, size_t* size, Byte* buf);
236 size_t read(MidiBuffer& dst, nframes_t start, nframes_t end, nframes_t offset=0);
241 MidiRingBuffer::read(double* time, size_t* size, Byte* buf)
243 bool success = MidiRingBufferBase<Byte>::full_read(sizeof(double), (Byte*)time);
245 success = MidiRingBufferBase<Byte>::full_read(sizeof(size_t), (Byte*)size);
247 success = MidiRingBufferBase<Byte>::full_read(*size, buf);
254 MidiRingBuffer::write(double time, size_t size, const Byte* buf)
256 //printf("MRB - write %#X %d %d with time %lf\n",
257 // buf[0], buf[1], buf[2], time);
261 if (write_space() < (sizeof(double) + sizeof(size_t) + size)) {
264 MidiRingBufferBase<Byte>::write(sizeof(double), (Byte*)&time);
265 MidiRingBufferBase<Byte>::write(sizeof(size_t), (Byte*)&size);
266 MidiRingBufferBase<Byte>::write(size, buf);
272 /** Read a block of MIDI events from buffer.
274 * Timestamps of events returned are relative to start (ie event with stamp 0
275 * occurred at start), with offset added.
278 MidiRingBuffer::read(MidiBuffer& dst, nframes_t start, nframes_t end, nframes_t offset)
280 if (read_space() == 0)
287 //printf("MRB - read %u .. %u + %u\n", start, end, offset);
289 while (read_space() > sizeof(double) + sizeof(size_t)) {
291 full_peek(sizeof(double), (Byte*)&ev.time());
296 bool success = MidiRingBufferBase<Byte>::full_read(sizeof(double), (Byte*)&ev.time());
298 success = MidiRingBufferBase<Byte>::full_read(sizeof(size_t), (Byte*)&ev.size());
301 std::cerr << "MRB: READ ERROR (time/size)" << std::endl;
305 if (ev.time() >= start) {
307 Byte* write_loc = dst.reserve(ev.time(), ev.size());
308 success = MidiRingBufferBase<Byte>::full_read(ev.size(), write_loc);
312 //printf("MRB - read event at time %lf\n", ev.time);
314 std::cerr << "MRB: READ ERROR (data)" << std::endl;
318 printf("MRB - SKIPPING EVENT (with time %f)\n", ev.time());
322 //printf("(R) read space: %zu\n", read_space());
328 } // namespace ARDOUR
330 #endif // __ardour_midi_ring_buffer_h__