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author | David Robillard <d@drobilla.net> | 2008-02-01 03:42:02 +0000 |
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committer | David Robillard <d@drobilla.net> | 2008-02-01 03:42:02 +0000 |
commit | a06c7eeef68cfe87589f557570f812da4391de96 (patch) | |
tree | 39d622cef75b668721d3144c8ded8b8cf033a17c /hosts/lv2-miditype.h | |
parent | 8c4e3d5e615e24561d183d13ee7d837fcca3c396 (diff) | |
download | lilv-a06c7eeef68cfe87589f557570f812da4391de96.tar.gz lilv-a06c7eeef68cfe87589f557570f812da4391de96.tar.bz2 lilv-a06c7eeef68cfe87589f557570f812da4391de96.zip |
Generic LV2 event support in lv2_jack_host.
git-svn-id: http://svn.drobilla.net/lad/slv2@1122 a436a847-0d15-0410-975c-d299462d15a1
Diffstat (limited to 'hosts/lv2-miditype.h')
-rw-r--r-- | hosts/lv2-miditype.h | 170 |
1 files changed, 0 insertions, 170 deletions
diff --git a/hosts/lv2-miditype.h b/hosts/lv2-miditype.h deleted file mode 100644 index 465d5d5..0000000 --- a/hosts/lv2-miditype.h +++ /dev/null @@ -1,170 +0,0 @@ -/**************************************************************************** - - lv2-miditype.h - header file for using MIDI in LV2 plugins - - Copyright (C) 2006 Lars Luthman <lars.luthman@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 - -****************************************************************************/ - -#ifndef LV2_MIDITYPE_H -#define LV2_MIDITYPE_H - - -/** This data structure is used to contain the MIDI events for one run() - cycle. The port buffer for a LV2 port that has the datatype - <http://ll-plugins.nongnu.org/lv2/ext/miditype> 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 - - size_t buffer_offset = 0; - *(double*)(midi_data->data + buffer_offset) = 12; - buffer_offset += sizeof(double); - *(size_t*)(midi_data->data + buffer_offset) = 3; - buffer_offset += sizeof(size_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); - *(size_t*)(midi_data->data + buffer_offset) = 3; - buffer_offset += sizeof(size_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 - - size_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); - size_t size = *(size_t*)(midi_data->data + buffer_offset); - buffer_offset += sizeof(size_t); - do_something_with_event(timestamp, size, - midi_data->data + buffer_offset); - buffer_offset += size; - } - - @endcode -*/ -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 - "size_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 and size_t is 4 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 |