[SCM] calf/master: + LV2: added missing LV2-MIDI extension header
js at users.alioth.debian.org
js at users.alioth.debian.org
Tue May 7 15:37:00 UTC 2013
The following commit has been merged in the master branch:
commit d3a978f1d4ea5a48367f7dade2828b84dabd2bbc
Author: kfoltman <kfoltman at 78b06b96-2940-0410-b7fc-879d825d01d8>
Date: Wed Jan 16 19:13:31 2008 +0000
+ LV2: added missing LV2-MIDI extension header
git-svn-id: https://calf.svn.sourceforge.net/svnroot/calf/trunk@106 78b06b96-2940-0410-b7fc-879d825d01d8
diff --git a/src/calf/lv2-midiport.h b/src/calf/lv2-midiport.h
new file mode 100644
index 0000000..30309b6
--- /dev/null
+++ b/src/calf/lv2-midiport.h
@@ -0,0 +1,177 @@
+/****************************************************************************
+
+ lv2-midiport.h - header file for using MIDI in LV2 plugins
+
+ Copyright (C) 2006 Lars Luthman <lars.luthman at gmail.com>
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU Lesser 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 Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 01222-1307 USA
+
+****************************************************************************/
+
+/** @file
+ This file contains the specification for an LV2 MIDI port extension.
+*/
+
+#ifndef LV2_MIDIPORT_H
+#define LV2_MIDIPORT_H
+
+
+/** This data structure is used to contain the MIDI events for one run()
+ cycle. The port buffer for an LV2 port of the type
+ <http://ll-plugins.nongnu.org/lv2/ext/MidiPort> should be a pointer
+ to an instance of this struct.
+
+ To store two Note On events on MIDI channel 0 in a buffer, with timestamps
+ 12 and 35.5, you could use something like this code (assuming that
+ midi_data is a variable of type LV2_MIDI):
+ @code
+
+ uint32_t buffer_offset = 0;
+ *(double*)(midi_data->data + buffer_offset) = 12;
+ buffer_offset += sizeof(double);
+ *(uint32_t*)(midi_data->data + buffer_offset) = 3;
+ buffer_offset += sizeof(uint32_t);
+ midi_data->data[buffer_offset++] = 0x90;
+ midi_data->data[buffer_offset++] = 0x48;
+ midi_data->data[buffer_offset++] = 0x64;
+ ++midi_data->event_count;
+
+ *(double*)(midi_data->data + buffer_offset) = 35.5;
+ buffer_offset += sizeof(double);
+ *(uint32_t*)(midi_data->data + buffer_offset) = 3;
+ buffer_offset += sizeof(uint32_t);
+ midi_data->data[buffer_offset++] = 0x90;
+ midi_data->data[buffer_offset++] = 0x55;
+ midi_data->data[buffer_offset++] = 0x64;
+ ++midi_data->event_count;
+
+ midi_data->size = buffer_offset;
+
+ @endcode
+
+ This would be done by the host in the case of an input port, and by the
+ plugin in the case of an output port. Whoever is writing events to the
+ buffer must also take care not to exceed the capacity of the data buffer.
+
+ To read events from a buffer, you could do something like this:
+ @code
+
+ uint32_t buffer_offset = 0;
+ uint32_t i;
+ for (i = 0; i < midi_data->event_count; ++i) {
+ double timestamp = *(double*)(midi_data->data + buffer_offset);
+ buffer_offset += sizeof(double);
+ uint32_t size = *(uint32_t*)(midi_data->data + buffer_offset);
+ buffer_offset += sizeof(uint32_t);
+ do_something_with_event(timestamp, size,
+ midi_data->data + buffer_offset);
+ buffer_offset += size;
+ }
+
+ @endcode
+
+ If you think this looks like too much code to simply read and write MIDI
+ events, take a look at the helper functions in lv2-midifunctions.h. They
+ are not an official part of this extension, but they can be convenient.
+*/
+typedef struct {
+
+ /** The number of MIDI events in the data buffer.
+ INPUT PORTS: It's the host's responsibility to set this field to the
+ number of MIDI events contained in the data buffer before calling the
+ plugin's run() function. The plugin may not change this field.
+ OUTPUT PORTS: It's the plugin's responsibility to set this field to the
+ number of MIDI events it has stored in the data buffer before returning
+ from the run() function. Any initial value should be ignored by the
+ plugin.
+ */
+ uint32_t event_count;
+
+ /** The size of the data buffer in bytes. It is set by the host and may not
+ be changed by the plugin. The host is allowed to change this between
+ run() calls.
+ */
+ uint32_t capacity;
+
+ /** The size of the initial part of the data buffer that actually contains
+ data.
+ INPUT PORTS: It's the host's responsibility to set this field to the
+ number of bytes used by all MIDI events it has written to the buffer
+ (including timestamps and size fields) before calling the plugin's
+ run() function. The plugin may not change this field.
+ OUTPUT PORTS: It's the plugin's responsibility to set this field to
+ the number of bytes used by all MIDI events it has written to the
+ buffer (including timestamps and size fields) before returning from
+ the run() function. Any initial value should be ignored by the plugin.
+ */
+ uint32_t size;
+
+ /** The data buffer that is used to store MIDI events. The events are packed
+ after each other, and the format of each event is as follows:
+
+ First there is a timestamp, which should have the type "double",
+ i.e. have the same bit size as a double and the same bit layout as a
+ double (whatever that is on the current platform). This timestamp gives
+ the offset from the beginning of the current cycle, in frames, that
+ the MIDI event occurs on. It must be strictly smaller than the 'nframes'
+ parameter to the current run() call. The MIDI events in the buffer must
+ be ordered by their timestamp, e.g. an event with a timestamp of 123.23
+ must be stored after an event with a timestamp of 65.0.
+
+ The second part of the event is a size field, which should have the type
+ "uint32_t" (as defined in the standard C header stddef.h). It should
+ contain the size of the MIDI data for this event, i.e. the number of
+ bytes used to store the actual MIDI event. The bytes used by the
+ timestamp and the size field should not be counted.
+
+ The third part of the event is the actual MIDI data. There are some
+ requirements that must be followed:
+
+ * Running status is not allowed. Every event must have its own status
+ byte.
+ * Note On events with velocity 0 are not allowed. These events are
+ equivalent to Note Off in standard MIDI streams, but in order to make
+ plugins and hosts easier to write, as well as more efficient, only
+ proper Note Off events are allowed as Note Off.
+ * "Realtime events" (status bytes 0xF8 to 0xFF) are allowed, but may not
+ occur inside other events like they are allowed to in hardware MIDI
+ streams.
+ * All events must be fully contained in a single data buffer, i.e. events
+ may not "wrap around" by storing the first few bytes in one buffer and
+ then wait for the next run() call to store the rest of the event. If
+ there isn't enough space in the current data buffer to store an event,
+ the event will either have to wait until next run() call, be ignored,
+ or compensated for in some more clever way.
+ * All events must be valid MIDI events. This means for example that
+ only the first byte in each event (the status byte) may have the eighth
+ bit set, that Note On and Note Off events are always 3 bytes long etc.
+ The MIDI writer (host or plugin) is responsible for writing valid MIDI
+ events to the buffer, and the MIDI reader (plugin or host) can assume
+ that all events are valid.
+
+ On a platform where double is 8 bytes the data buffer layout for a
+ 3-byte event followed by a 4-byte event may look something like this:
+ _______________________________________________________________
+ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ...
+ |TIMESTAMP 1 |SIZE 1 |DATA |TIMESTAMP 2 |SIZE 2 |DATA | ...
+
+ */
+ unsigned char* data;
+
+} LV2_MIDI;
+
+
+
+#endif
--
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