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livetrax/libs/evoral/libsmf/smf.h
Robin Gareus cd53301d06
Significantly speed up loading SMF tempo-maps 
Files that have many tracks, each with tempo information
were near impossible to load (30+ mins on modern 4.2Ghz CPU!),
because tempo is parsed incrementally:

```
For each new track:
  for each new tempo-event:
    rewind()
    for each loaded track so far:
      for each event on this track so far
```

This reduces the complexity from O(tracks^2 * tempos^2)
to O(tracks * tempos).

"Come Thou Fount Tempo Map.mid" has 238 Tracks and 56168 total
Tempo Changes (236 per track). This now requires only 56168 iterations
in smf_create_tempo_map_and_compute_seconds, rather than 1.64e+9
iterations
2022-02-05 17:33:21 +01:00

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/*-
* Copyright (c) 2007, 2008 Edward Tomasz Napierała <trasz@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* ALTHOUGH THIS SOFTWARE IS MADE OF WIN AND SCIENCE, IT IS PROVIDED BY THE
* AUTHOR AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
* OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
/**
* \file
*
* Public interface declaration for libsmf, Standard MIDI File format library.
*/
/**
*
* \page libsmf libsmf - general usage instructions
*
* An smf_t structure represents a "song". Every valid smf contains one or more tracks.
* Tracks contain zero or more events. Libsmf doesn't care about actual MIDI data, as long
* as it is valid from the MIDI specification point of view - it may be realtime message,
* SysEx, whatever.
*
* The only field in smf_t, smf_track_t, smf_event_t and smf_tempo_t structures your
* code may modify is event->midi_buffer and event->midi_buffer_length. Do not modify
* other fields, _ever_. You may read them, though. Do not declare static instances
* of these types, i.e. never do something like this: "smf_t smf;". Always use
* "smf_t *smf = smf_new();". The same applies to smf_track_t and smf_event_t.
*
* Say you want to load a Standard MIDI File (.mid) file and play it back somehow.
* This is (roughly) how you do this:
*
* \code
* smf_t *smf;
* smf_event_t *event;
*
* smf = smf_load(file_name);
* if (smf == NULL) {
* Whoops, something went wrong.
* return;
* }
*
* while ((event = smf_get_next_event(smf)) != NULL) {
* if (smf_event_is_metadata(event))
* continue;
*
* wait until event->time_seconds.
* feed_to_midi_output(event->midi_buffer, event->midi_buffer_length);
* }
*
* smf_delete(smf);
*
* \endcode
*
* Saving works like this:
*
* \code
*
* smf_t *smf;
* smf_track_t *track;
* smf_event_t *event;
*
* smf = smf_new();
* if (smf == NULL) {
* Whoops.
* return;
* }
*
* for (int i = 1; i <= number of tracks; i++) {
* track = smf_track_new();
* if (track == NULL) {
* Whoops.
* return;
* }
*
* smf_add_track(smf, track);
*
* for (int j = 1; j <= number of events you want to put into this track; j++) {
* event = smf_event_new_from_pointer(your MIDI message, message length);
* if (event == NULL) {
* Whoops.
* return;
* }
*
* smf_track_add_event_seconds(track, event, seconds since start of the song);
* }
* }
*
* ret = smf_save(smf, file_name);
* if (ret) {
* Whoops, saving failed for some reason.
* return;
* }
*
* smf_delete(smf);
*
* \endcode
*
* There are two basic ways of getting MIDI data out of smf - sequential or by track/event number.
* You may mix them if you need to. First one is used in the example above - seek to the point
* from which you want the playback to start (using smf_seek_to_seconds(), smf_seek_to_pulses()
* or smf_seek_to_event()) and then do smf_get_next_event() in loop, until it returns NULL.
* Calling smf_load() causes the smf to be rewound to the start of the song.
*
* Getting events by number works like this:
*
* \code
*
* smf_track_t *track = smf_get_track_by_number(smf, track_number);
* smf_event_t *event = smf_track_get_event_by_number(track, event_number);
*
* \endcode
*
* To create new event, use smf_event_new(), smf_event_new_from_pointer() or
* smf_event_new_from_bytes(). First one creates an empty event - you need to manually allocate
* (using malloc(3)) buffer for MIDI data, write MIDI data into it, put the address of that
* buffer into event->midi_buffer, and the length of MIDI data into event->midi_buffer_length.
* Note that deleting the event (using smf_event_delete()) will free the buffer.
*
* Second form does most of this for you: it takes an address of the buffer containing MIDI data,
* allocates storage and copies MIDI data into it.
*
* Third form is useful for manually creating short events, up to three bytes in length, for
* example Note On or Note Off events. It simply takes three bytes and creates MIDI event
* containing them. If you need to create MIDI message that takes only two bytes, pass -1 as
* the third byte. For one byte message (System Realtime), pass -1 as second and third byte.
*
* To free an event, use smf_event_delete().
*
* To add event to the track, use smf_track_add_event_delta_pulses(), smf_track_add_event_pulses(),
* or smf_track_add_event_seconds(). The difference between them is in the way you specify the
* time of the event - with the first one, you specify it as an interval, in pulses, from the
* previous event in this track; with the second one, you specify it as pulses from the start
* of the song, and with the last one, you specify it as seconds from the start of the song.
* Obviously, the first version can only append events at the end of the track.
*
* To remove an event from the track it's attached to, use smf_event_remove_from_track().
* You may want to free the event (using smf_event_delete()) afterwards.
*
* To create new track, use smf_track_new(). To add track to the smf, use smf_add_track().
* To remove track from its smf, use smf_track_remove_from_smf(). To free the track structure,
* use smf_track_delete().
*
* Note that libsmf keeps things consistent. If you free (using smf_track_delete()) a track
* that is attached to an smf and contains events, libsmf will detach the events, free them,
* detach the track, free it etc.
*
* Tracks and events are numbered consecutively, starting from one. If you remove a track
* or event, the rest of tracks/events will get renumbered. To get the number of a given
* event in its track, use event->event_number. To get the number of track in its smf, use
* track->track_number. To get the number of events in the track, use track->number_of_events.
* To get the number of tracks in the smf, use smf->number_of_tracks.
*
* In SMF File Format, each track has to end with End Of Track metaevent. If you load SMF file
* using smf_load(), that will be the case. If you want to create or edit an SMF, you don't
* need to worry about EOT events; libsmf automatically takes care of them for you. If you
* try to save an SMF with tracks that do not end with EOTs, smf_save() will append them.
* If you try to add event that happens after EOT metaevent, libsmf will remove the EOT.
* If you want to add EOT manually, you can, of course, using smf_track_add_eot_seconds()
* or smf_track_add_eot_pulses().
*
* Each event carries three time values - event->time_seconds, which is seconds since
* the start of the song, event->time_pulses, which is PPQN clocks since the start of
* the song, and event->delta_pulses, which is PPQN clocks since the previous event
* in that track. These values are invalid if the event is not attached to the track.
* If event is attached, all three values are valid. Time of the event is specified when
* adding the event (using smf_track_add_event_seconds(), smf_track_add_event_pulses() or
* smf_track_add_event_delta_pulses()); the remaining two values are computed from that.
*
* Tempo related stuff happens automatically - when you add a metaevent that is Tempo PropertyChange or
* Time Signature, libsmf adds that event to the tempo map. If you remove Tempo PropertyChange event
* that is in the middle of the song, the rest of the events will have their event->time_seconds
* recomputed from event->time_pulses before smf_event_remove_from_track() function returns.
* Adding Tempo PropertyChange in the middle of the song works in a similar way.
*
* MIDI data (event->midi_buffer) is always kept in normalized form - it always begins with
* status byte (no running status), there are no System Realtime events embedded in them etc.
* Events like SysExes are in "on the wire" form, without embedded length that is used in SMF
* file format. Obviously libsmf "normalizes" MIDI data during loading and "denormalizes" (adding
* length to SysExes, escaping System Common and System Realtime messages etc) during writing.
*
* Note that you always have to first add the track to smf, and then add events to the track.
* Doing it the other way around will trip asserts. Also, try to add events at the end of the
* track and remove them from the end of the track, that's much more efficient.
*
* All the libsmf functions have prefix "smf_". First argument for routines whose names start
* with "smf_event_" is "smf_event_t *", for routines whose names start with "smf_track_" -
* "smf_track_t *", and for plain "smf_" - "smf_t *". The only exception are smf_whatever_new
* routines. Library does not use any global variables and is thread-safe, as long as you
* don't try to work on the same SMF (smf_t and its descendant tracks and events) from several
* threads at once without protecting it with mutex. Library depends on glib and nothing else.
* License is BSD, two clause, which basically means you can use it freely in your software,
* both Open Source (including GPL) and closed source.
*
*/
#ifndef SMF_H
#define SMF_H
#ifdef __cplusplus
extern "C" {
#endif
#include <stdio.h>
#include <stdint.h>
#include <glib.h>
#if defined(__GNUC__) && __GNUC__ >= 4
#define WARN_UNUSED_RESULT __attribute__ ((warn_unused_result))
#else
#define WARN_UNUSED_RESULT
#endif
/** Represents a "song", that is, collection of one or more tracks. */
struct smf_struct {
int format;
/** These fields are extracted from "division" field of MThd header.
* Valid is _either_ ppqn or frames_per_second/resolution. */
uint16_t ppqn;
int frames_per_second;
int resolution;
int number_of_tracks;
/** These are private fields using only by loading and saving routines. */
FILE *stream;
void *file_buffer;
size_t file_buffer_length;
size_t next_chunk_offset;
int expected_number_of_tracks;
/** Private, used by smf.c. */
GPtrArray *tracks_array;
double last_seek_position;
int need_tempo_map_compute;
/** Private, used by smf_tempo.c. */
/** Array of pointers to smf_tempo_struct. */
GPtrArray *tempo_array;
};
typedef struct smf_struct smf_t;
/** Describes a single tempo or time signature change. */
struct smf_tempo_struct {
size_t time_pulses;
int microseconds_per_quarter_note;
int numerator;
int denominator;
int clocks_per_click;
int notes_per_note;
};
typedef struct smf_tempo_struct smf_tempo_t;
/** Represents a single track. */
struct smf_track_struct {
smf_t *smf;
int track_number;
size_t number_of_events;
/* this will be set from the SMF file if present, during loading */
char* name;
char* instrument;
/** These are private fields using only by loading and saving routines. */
void *file_buffer;
size_t file_buffer_length;
int last_status; /* Used for "running status". */
/** Private, used by smf.c. */
/** Offset into buffer, used in parse_next_event(). */
size_t next_event_offset;
size_t next_event_number;
/** Absolute time of next event on events_queue. */
size_t time_of_next_event;
GPtrArray *events_array;
};
typedef struct smf_track_struct smf_track_t;
/** Represents a single MIDI event or metaevent. */
struct smf_event_struct {
/** Pointer to the track, or NULL if event is not attached. */
smf_track_t *track;
/** Number of this event in the track. Events are numbered consecutively, starting from 1. */
size_t event_number;
/** Note that the time fields are invalid, if event is not attached to a track. */
/** Time, in pulses, since the previous event on this track. */
int32_t delta_time_pulses;
/** Time, in pulses, since the start of the song. */
size_t time_pulses;
/** Tracks are numbered consecutively, starting from 1. */
int track_number;
/** Pointer to the buffer containing MIDI message. This is freed by smf_event_delete. */
uint8_t *midi_buffer;
/** Length of the MIDI message in the buffer, in bytes. */
size_t midi_buffer_length;
};
typedef struct smf_event_struct smf_event_t;
/* Routines for manipulating smf_t. */
smf_t *smf_new(void) WARN_UNUSED_RESULT;
void smf_delete(smf_t *smf);
int smf_set_format(smf_t *smf, int format) WARN_UNUSED_RESULT;
int smf_set_ppqn(smf_t *smf, uint16_t ppqn) WARN_UNUSED_RESULT;
char *smf_decode(const smf_t *smf) WARN_UNUSED_RESULT;
smf_track_t *smf_get_track_by_number(const smf_t *smf, int track_number) WARN_UNUSED_RESULT;
smf_event_t *smf_peek_next_event(smf_t *smf) WARN_UNUSED_RESULT;
smf_event_t *smf_get_next_event(smf_t *smf) WARN_UNUSED_RESULT;
void smf_skip_next_event(smf_t *smf);
void smf_rewind(smf_t *smf);
int smf_seek_to_pulses(smf_t *smf, size_t pulses) WARN_UNUSED_RESULT;
int smf_seek_to_event(smf_t *smf, const smf_event_t *event) WARN_UNUSED_RESULT;
size_t smf_get_length_pulses(const smf_t *smf) WARN_UNUSED_RESULT;
int smf_event_is_last(const smf_event_t *event) WARN_UNUSED_RESULT;
void smf_add_track(smf_t *smf, smf_track_t *track);
void smf_track_remove_from_smf(smf_track_t *track);
/* Routines for manipulating smf_track_t. */
smf_track_t *smf_track_new(void) WARN_UNUSED_RESULT;
void smf_track_delete(smf_track_t *track);
smf_event_t *smf_track_get_next_event(smf_track_t *track) WARN_UNUSED_RESULT;
smf_event_t *smf_track_get_event_by_number(const smf_track_t *track, size_t num) WARN_UNUSED_RESULT;
smf_event_t *smf_track_get_last_event(const smf_track_t *track) WARN_UNUSED_RESULT;
void smf_track_add_event_delta_pulses(smf_track_t *track, smf_event_t *event, uint32_t delta);
void smf_track_add_event_pulses(smf_track_t *track, smf_event_t *event, size_t pulses);
int smf_track_add_eot_delta_pulses(smf_track_t *track, uint32_t delta) WARN_UNUSED_RESULT;
int smf_track_add_eot_pulses(smf_track_t *track, size_t pulses) WARN_UNUSED_RESULT;
void smf_event_remove_from_track(smf_event_t *event);
/* Routines for manipulating smf_event_t. */
smf_event_t *smf_event_new(void) WARN_UNUSED_RESULT;
smf_event_t *smf_event_new_from_pointer(const void *midi_data, size_t len) WARN_UNUSED_RESULT;
smf_event_t *smf_event_new_from_bytes(int byte1, int byte2, int byte3) WARN_UNUSED_RESULT;
smf_event_t *smf_event_new_textual(int type, const char *text) WARN_UNUSED_RESULT;
void smf_event_delete(smf_event_t *event);
int smf_event_is_valid(const smf_event_t *event) WARN_UNUSED_RESULT;
int smf_event_is_metadata(const smf_event_t *event) WARN_UNUSED_RESULT;
int smf_event_is_system_realtime(const smf_event_t *event) WARN_UNUSED_RESULT;
int smf_event_is_system_common(const smf_event_t *event) WARN_UNUSED_RESULT;
int smf_event_is_sysex(const smf_event_t *event) WARN_UNUSED_RESULT;
int smf_event_is_eot(const smf_event_t *event) WARN_UNUSED_RESULT;
int smf_event_is_textual(const smf_event_t *event) WARN_UNUSED_RESULT;
char *smf_event_decode(const smf_event_t *event) WARN_UNUSED_RESULT;
char *smf_event_extract_text(const smf_event_t *event) WARN_UNUSED_RESULT;
/* Routines for dealing with Variable Length Quantities (VLQ's).
Slightly odd names reflect original static names within libsmf
*/
int smf_format_vlq (unsigned char *buf, int length, unsigned long value);
int smf_extract_vlq(const unsigned char *buf, const size_t buffer_length, uint32_t *value, uint32_t *len);
/* Routines for loading SMF files. */
smf_t *smf_load(FILE *) WARN_UNUSED_RESULT;
smf_t *smf_load_from_memory(void *buffer, const size_t buffer_length) WARN_UNUSED_RESULT;
/* Routine for writing SMF files. */
int smf_save(smf_t *smf, FILE *file) WARN_UNUSED_RESULT;
/* Routines for manipulating smf_tempo_t. */
smf_tempo_t *smf_get_tempo_by_pulses(const smf_t *smf, size_t pulses) WARN_UNUSED_RESULT;
smf_tempo_t *smf_get_tempo_by_seconds(const smf_t *smf, double seconds) WARN_UNUSED_RESULT;
int smf_get_tempo_count (const smf_t *smf) WARN_UNUSED_RESULT;
smf_tempo_t *smf_get_tempo_by_number(const smf_t *smf, size_t number) WARN_UNUSED_RESULT;
smf_tempo_t *smf_get_last_tempo(const smf_t *smf) WARN_UNUSED_RESULT;
const char *smf_get_version(void) WARN_UNUSED_RESULT;
#ifdef __cplusplus
}
#endif
#endif /* SMF_H */
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