jack-headers/midiport.h

198 lines
6.7 KiB
C

/*
Copyright (C) 2004 Ian Esten
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 2.1 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 02111-1307, USA.
*/
#ifndef __JACK_MIDIPORT_H
#define __JACK_MIDIPORT_H
#ifdef __cplusplus
extern "C" {
#endif
#include <jack/weakmacros.h>
#include <jack/types.h>
#include <stdlib.h>
/** Type for raw event data contained in @ref jack_midi_event_t. */
typedef unsigned char jack_midi_data_t;
/** A Jack MIDI event. */
typedef struct _jack_midi_event
{
jack_nframes_t time; /**< Sample index at which event is valid */
size_t size; /**< Number of bytes of data in \a buffer */
jack_midi_data_t *buffer; /**< Raw MIDI data */
} jack_midi_event_t;
/**
* @defgroup MIDIAPI Reading and writing MIDI data
* @{
*/
/** Get number of events in a port buffer.
*
* @param port_buffer Port buffer from which to retrieve event.
* @return number of events inside @a port_buffer
*/
uint32_t
jack_midi_get_event_count(void* port_buffer) JACK_OPTIONAL_WEAK_EXPORT;
/** Get a MIDI event from an event port buffer.
*
* Jack MIDI is normalised, the MIDI event returned by this function is
* guaranteed to be a complete MIDI event (the status byte will always be
* present, and no realtime events will interspered with the event).
*
* This rule does not apply to System Exclusive MIDI messages
* since they can be of arbitrary length.
* To maintain smooth realtime operation such events CAN be deliverd
* as multiple, non-normalised events.
* The maximum size of one event "chunk" depends on the MIDI backend in use.
* For example the midiseq driver will create chunks of 256 bytes.
* The first SysEx "chunked" event starts with 0xF0 and the last
* delivered chunk ends with 0xF7.
* To receive the full SysEx message, a caller of jack_midi_event_get()
* must concatenate chunks until a chunk ends with 0xF7.
*
* @param event Event structure to store retrieved event in.
* @param port_buffer Port buffer from which to retrieve event.
* @param event_index Index of event to retrieve.
* @return 0 on success, ENODATA if buffer is empty.
*/
int
jack_midi_event_get(jack_midi_event_t *event,
void *port_buffer,
uint32_t event_index) JACK_OPTIONAL_WEAK_EXPORT;
/** Clear an event buffer.
*
* This should be called at the beginning of each process cycle before calling
* @ref jack_midi_event_reserve or @ref jack_midi_event_write. This
* function may not be called on an input port's buffer.
*
* @param port_buffer Port buffer to clear (must be an output port buffer).
*/
void
jack_midi_clear_buffer(void *port_buffer) JACK_OPTIONAL_WEAK_EXPORT;
/** Reset an event buffer (from data allocated outside of JACK).
*
* This should be called at the beginning of each process cycle before calling
* @ref jack_midi_event_reserve or @ref jack_midi_event_write. This
* function may not be called on an input port's buffer.
*
* @deprecated Please use jack_midi_clear_buffer().
*
* @param port_buffer Port buffer to reset.
*/
void
jack_midi_reset_buffer(void *port_buffer) JACK_OPTIONAL_WEAK_DEPRECATED_EXPORT;
/** Get the size of the largest event that can be stored by the port.
*
* This function returns the current space available, taking into account
* events already stored in the port.
*
* @param port_buffer Port buffer to check size of.
*/
size_t
jack_midi_max_event_size(void* port_buffer) JACK_OPTIONAL_WEAK_EXPORT;
/** Allocate space for an event to be written to an event port buffer.
*
* Clients are to write the actual event data to be written starting at the
* pointer returned by this function. Clients must not write more than
* @a data_size bytes into this buffer. Clients must write normalised
* MIDI data to the port - no running status and no (1-byte) realtime
* messages interspersed with other messages (realtime messages are fine
* when they occur on their own, like other messages).
*
* Events must be written in order, sorted by their sample offsets.
* JACK will not sort the events for you, and will refuse to store
* out-of-order events.
*
* @param port_buffer Buffer to write event to.
* @param time Sample offset of event.
* @param data_size Length of event's raw data in bytes.
* @return Pointer to the beginning of the reserved event's data buffer, or
* NULL on error (ie not enough space).
*/
jack_midi_data_t*
jack_midi_event_reserve(void *port_buffer,
jack_nframes_t time,
size_t data_size) JACK_OPTIONAL_WEAK_EXPORT;
/** Write an event into an event port buffer.
*
* This function is simply a wrapper for @ref jack_midi_event_reserve
* which writes the event data into the space reserved in the buffer.
*
* Clients must not write more than
* @a data_size bytes into this buffer. Clients must write normalised
* MIDI data to the port - no running status and no (1-byte) realtime
* messages interspersed with other messages (realtime messages are fine
* when they occur on their own, like other messages).
*
* Events must be written in order, sorted by their sample offsets.
* JACK will not sort the events for you, and will refuse to store
* out-of-order events.
*
* @param port_buffer Buffer to write event to.
* @param time Sample offset of event.
* @param data Message data to be written.
* @param data_size Length of @a data in bytes.
* @return 0 on success, ENOBUFS if there's not enough space in buffer for event.
*/
int
jack_midi_event_write(void *port_buffer,
jack_nframes_t time,
const jack_midi_data_t *data,
size_t data_size) JACK_OPTIONAL_WEAK_EXPORT;
/** Get the number of events that could not be written to @a port_buffer.
*
* This function returning a non-zero value implies @a port_buffer is full.
* Currently the only way this can happen is if events are lost on port mixdown.
*
* @param port_buffer Port to receive count for.
* @returns Number of events that could not be written to @a port_buffer.
*/
uint32_t
jack_midi_get_lost_event_count(void *port_buffer) JACK_OPTIONAL_WEAK_EXPORT;
/**@}*/
#ifdef __cplusplus
}
#endif
#endif /* __JACK_MIDIPORT_H */