smf_decode.c

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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.
 *
 */

#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <math.h>
#include <errno.h>
#ifdef PLATFORM_WINDOWS
#include <winsock2.h>
#else
#include <arpa/inet.h>
#endif
#include <stdint.h>
#include "smf.h"
#include "smf_private.h"

#define BUFFER_SIZE 1024

int
smf_event_is_metadata(const smf_event_t *event)
{
        assert(event->midi_buffer);
        assert(event->midi_buffer_length > 0);
        
        if (event->midi_buffer[0] == 0xFF)
                return (1);

        return (0);
}

int
smf_event_is_system_realtime(const smf_event_t *event)
{
        assert(event->midi_buffer);
        assert(event->midi_buffer_length > 0);

        if (smf_event_is_metadata(event))
                return (0);
        
        if (event->midi_buffer[0] >= 0xF8)
                return (1);

        return (0);
}

int
smf_event_is_system_common(const smf_event_t *event)
{
        assert(event->midi_buffer);
        assert(event->midi_buffer_length > 0);

        if (event->midi_buffer[0] >= 0xF0 && event->midi_buffer[0] <= 0xF7)
                return (1);

        return (0);
}
int
smf_event_is_sysex(const smf_event_t *event)
{
        assert(event->midi_buffer);
        assert(event->midi_buffer_length > 0);
        
        if (event->midi_buffer[0] == 0xF0)
                return (1);

        return (0);
}

static char *
smf_event_decode_textual(const smf_event_t *event, const char *name)
{
        int off = 0;
        char *buf, *extracted;

        buf = (char*)malloc(BUFFER_SIZE);
        if (buf == NULL) {
                g_critical("smf_event_decode_textual: malloc failed.");
                return (NULL);
        }

        extracted = smf_event_extract_text(event);
        if (extracted == NULL) {
                free(buf);
                return (NULL);
        }

        snprintf(buf + off, BUFFER_SIZE - off, "%s: %s", name, extracted);

        return (buf);
}

static char *
smf_event_decode_metadata(const smf_event_t *event)
{
        int off = 0, mspqn, flats, isminor;
        char *buf;

        static const char *const major_keys[] = {"Fb", "Cb", "Gb", "Db", "Ab",
                "Eb", "Bb", "F", "C", "G", "D", "A", "E", "B", "F#", "C#", "G#"};

        static const char *const minor_keys[] = {"Dbm", "Abm", "Ebm", "Bbm", "Fm",
                "Cm", "Gm", "Dm", "Am", "Em", "Bm", "F#m", "C#m", "G#m", "D#m", "A#m", "E#m"};

        assert(smf_event_is_metadata(event));

        switch (event->midi_buffer[1]) {
                case 0x01:
                        return (smf_event_decode_textual(event, "Text"));

                case 0x02:
                        return (smf_event_decode_textual(event, "Copyright"));

                case 0x03:
                        return (smf_event_decode_textual(event, "Sequence/Track Name"));

                case 0x04:
                        return (smf_event_decode_textual(event, "Instrument"));

                case 0x05:
                        return (smf_event_decode_textual(event, "Lyric"));

                case 0x06:
                        return (smf_event_decode_textual(event, "Marker"));

                case 0x07:
                        return (smf_event_decode_textual(event, "Cue Point"));

                case 0x08:
                        return (smf_event_decode_textual(event, "Program Name"));

                case 0x09:
                        return (smf_event_decode_textual(event, "Device (Port) Name"));

                default:
                        break;
        }

        buf = (char*)malloc(BUFFER_SIZE);
        if (buf == NULL) {
                g_critical("smf_event_decode_metadata: malloc failed.");
                return (NULL);
        }

        switch (event->midi_buffer[1]) {
                case 0x00:
                        off += snprintf(buf + off, BUFFER_SIZE - off, "Sequence number");
                        break;

                /* http://music.columbia.edu/pipermail/music-dsp/2004-August/061196.html */
                case 0x20:
                        if (event->midi_buffer_length < 4) {
                                g_critical("smf_event_decode_metadata: truncated MIDI message.");
                                goto error;
                        }

                        off += snprintf(buf + off, BUFFER_SIZE - off, "Channel Prefix: %d", event->midi_buffer[3]);
                        break;

                case 0x21:
                        if (event->midi_buffer_length < 4) {
                                g_critical("smf_event_decode_metadata: truncated MIDI message.");
                                goto error;
                        }

                        off += snprintf(buf + off, BUFFER_SIZE - off, "MIDI Port: %d", event->midi_buffer[3]);
                        break;

                case 0x2F:
                        off += snprintf(buf + off, BUFFER_SIZE - off, "End Of Track");
                        break;

                case 0x51:
                        if (event->midi_buffer_length < 6) {
                                g_critical("smf_event_decode_metadata: truncated MIDI message.");
                                goto error;
                        }

                        mspqn = (event->midi_buffer[3] << 16) + (event->midi_buffer[4] << 8) + event->midi_buffer[5];

                        off += snprintf(buf + off, BUFFER_SIZE - off, "Tempo: %d microseconds per quarter note, %.2f BPM",
                                mspqn, 60000000.0 / (double)mspqn);
                        break;

                case 0x54:
                        off += snprintf(buf + off, BUFFER_SIZE - off, "SMPTE Offset");
                        break;

                case 0x58:
                        if (event->midi_buffer_length < 7) {
                                g_critical("smf_event_decode_metadata: truncated MIDI message.");
                                goto error;
                        }

                        off += snprintf(buf + off, BUFFER_SIZE - off,
                                "Time Signature: %d/%d, %d clocks per click, %d notated 32nd notes per quarter note",
                                event->midi_buffer[3], (int)pow((double)2, event->midi_buffer[4]), event->midi_buffer[5],
                                event->midi_buffer[6]);
                        break;

                case 0x59:
                        if (event->midi_buffer_length < 5) {
                                g_critical("smf_event_decode_metadata: truncated MIDI message.");
                                goto error;
                        }

                        flats = event->midi_buffer[3];
                        isminor = event->midi_buffer[4];

                        if (isminor != 0 && isminor != 1) {
                                g_critical("smf_event_decode_metadata: last byte of the Key Signature event has invalid value %d.", isminor);
                                goto error;
                        }

                        off += snprintf(buf + off, BUFFER_SIZE - off, "Key Signature: ");

                        if (flats > 8 && flats < 248) {
                                off += snprintf(buf + off, BUFFER_SIZE - off, "%d %s, %s key", abs((int8_t)flats),
                                        flats > 127 ? "flats" : "sharps", isminor ? "minor" : "major");
                        } else {
                                int i = (flats - 248) & 255;

                                assert(i >= 0 && (size_t)i < sizeof(minor_keys) / sizeof(*minor_keys));
                                assert(i >= 0 && (size_t)i < sizeof(major_keys) / sizeof(*major_keys));

                                if (isminor)
                                        off += snprintf(buf + off, BUFFER_SIZE - off, "%s", minor_keys[i]);
                                else
                                        off += snprintf(buf + off, BUFFER_SIZE - off, "%s", major_keys[i]);
                        }

                        break;

                case 0x7F:
                        off += snprintf(buf + off, BUFFER_SIZE - off, "Proprietary (aka Sequencer) Event, length %zu",
                                event->midi_buffer_length);
                        break;

                default:
                        goto error;
        }

        assert (off <= BUFFER_SIZE);
        return (buf);

error:
        free(buf);

        return (NULL);
}

static char *
smf_event_decode_system_realtime(const smf_event_t *event)
{
        int off = 0;
        char *buf;

        assert(smf_event_is_system_realtime(event));

        if (event->midi_buffer_length != 1) {
                g_critical("smf_event_decode_system_realtime: event length is not 1.");
                return (NULL);
        }

        buf = (char*)malloc(BUFFER_SIZE);
        if (buf == NULL) {
                g_critical("smf_event_decode_system_realtime: malloc failed.");
                return (NULL);
        }

        switch (event->midi_buffer[0]) {
                case 0xF8:
                        off += snprintf(buf + off, BUFFER_SIZE - off, "MIDI Clock (realtime)");
                        break;

                case 0xF9:
                        off += snprintf(buf + off, BUFFER_SIZE - off, "Tick (realtime)");
                        break;

                case 0xFA:
                        off += snprintf(buf + off, BUFFER_SIZE - off, "MIDI Start (realtime)");
                        break;

                case 0xFB:
                        off += snprintf(buf + off, BUFFER_SIZE - off, "MIDI Continue (realtime)");
                        break;

                case 0xFC:
                        off += snprintf(buf + off, BUFFER_SIZE - off, "MIDI Stop (realtime)");
                        break;

                case 0xFE:
                        off += snprintf(buf + off, BUFFER_SIZE - off, "Active Sense (realtime)");
                        break;

                default:
                        free(buf);
                        return (NULL);
        }

        assert (off <= BUFFER_SIZE);
        return (buf);
}

static char *
smf_event_decode_sysex(const smf_event_t *event)
{
        int off = 0;
        char *buf, manufacturer, subid, subid2;

        assert(smf_event_is_sysex(event));

        if (event->midi_buffer_length < 5) {
                g_critical("smf_event_decode_sysex: truncated MIDI message.");
                return (NULL);
        }

        buf = (char*)malloc(BUFFER_SIZE);
        if (buf == NULL) {
                g_critical("smf_event_decode_sysex: malloc failed.");
                return (NULL);
        }

        manufacturer = event->midi_buffer[1];

        if (manufacturer == 0x7F) {
                off += snprintf(buf + off, BUFFER_SIZE - off, "SysEx, realtime, channel %d", event->midi_buffer[2]);
        } else if (manufacturer == 0x7E) {
                off += snprintf(buf + off, BUFFER_SIZE - off, "SysEx, non-realtime, channel %d", event->midi_buffer[2]);
        } else {
                off += snprintf(buf + off, BUFFER_SIZE - off, "SysEx, manufacturer 0x%x", manufacturer);

                assert (off <= BUFFER_SIZE);
                return (buf);
        }

        subid = event->midi_buffer[3];
        subid2 = event->midi_buffer[4];

        if (subid == 0x01)
                off += snprintf(buf + off, BUFFER_SIZE - off, ", Sample Dump Header");

        else if (subid == 0x02)
                off += snprintf(buf + off, BUFFER_SIZE - off, ", Sample Dump Data Packet");

        else if (subid == 0x03)
                off += snprintf(buf + off, BUFFER_SIZE - off, ", Sample Dump Request");

        else if (subid == 0x04 && subid2 == 0x01)
                off += snprintf(buf + off, BUFFER_SIZE - off, ", Master Volume");

        else if (subid == 0x05 && subid2 == 0x01)
                off += snprintf(buf + off, BUFFER_SIZE - off, ", Sample Dump Loop Point Retransmit");

        else if (subid == 0x05 && subid2 == 0x02)
                off += snprintf(buf + off, BUFFER_SIZE - off, ", Sample Dump Loop Point Request");

        else if (subid == 0x06 && subid2 == 0x01)
                off += snprintf(buf + off, BUFFER_SIZE - off, ", Identity Request");

        else if (subid == 0x06 && subid2 == 0x02)
                off += snprintf(buf + off, BUFFER_SIZE - off, ", Identity Reply");

        else if (subid == 0x08 && subid2 == 0x00)
                off += snprintf(buf + off, BUFFER_SIZE - off, ", Bulk Tuning Dump Request");

        else if (subid == 0x08 && subid2 == 0x01)
                off += snprintf(buf + off, BUFFER_SIZE - off, ", Bulk Tuning Dump");

        else if (subid == 0x08 && subid2 == 0x02)
                off += snprintf(buf + off, BUFFER_SIZE - off, ", Single Note Tuning Change");

        else if (subid == 0x08 && subid2 == 0x03)
                off += snprintf(buf + off, BUFFER_SIZE - off, ", Bulk Tuning Dump Request (Bank)");

        else if (subid == 0x08 && subid2 == 0x04)
                off += snprintf(buf + off, BUFFER_SIZE - off, ", Key Based Tuning Dump");

        else if (subid == 0x08 && subid2 == 0x05)
                off += snprintf(buf + off, BUFFER_SIZE - off, ", Scale/Octave Tuning Dump, 1 byte format");

        else if (subid == 0x08 && subid2 == 0x06)
                off += snprintf(buf + off, BUFFER_SIZE - off, ", Scale/Octave Tuning Dump, 2 byte format");

        else if (subid == 0x08 && subid2 == 0x07)
                off += snprintf(buf + off, BUFFER_SIZE - off, ", Single Note Tuning Change (Bank)");

        else if (subid == 0x09)
                off += snprintf(buf + off, BUFFER_SIZE - off, ", General MIDI %s", subid2 == 0 ? "disable" : "enable");

        else if (subid == 0x7C)
                off += snprintf(buf + off, BUFFER_SIZE - off, ", Sample Dump Wait");

        else if (subid == 0x7D)
                off += snprintf(buf + off, BUFFER_SIZE - off, ", Sample Dump Cancel");

        else if (subid == 0x7E)
                off += snprintf(buf + off, BUFFER_SIZE - off, ", Sample Dump NAK");

        else if (subid == 0x7F)
                off += snprintf(buf + off, BUFFER_SIZE - off, ", Sample Dump ACK");

        else
                off += snprintf(buf + off, BUFFER_SIZE - off, ", Unknown");

        assert (off <= BUFFER_SIZE);
        return (buf);
}

static char *
smf_event_decode_system_common(const smf_event_t *event)
{
        int off = 0;
        char *buf;

        assert(smf_event_is_system_common(event));

        if (smf_event_is_sysex(event))
                return (smf_event_decode_sysex(event));

        buf = (char*)malloc(BUFFER_SIZE);
        if (buf == NULL) {
                g_critical("smf_event_decode_system_realtime: malloc failed.");
                return (NULL);
        }

        switch (event->midi_buffer[0]) {
                case 0xF1:
                        off += snprintf(buf + off, BUFFER_SIZE - off, "MTC Quarter Frame");
                        break;

                case 0xF2:
                        off += snprintf(buf + off, BUFFER_SIZE - off, "Song Position Pointer");
                        break;

                case 0xF3:
                        off += snprintf(buf + off, BUFFER_SIZE - off, "Song Select");
                        break;

                case 0xF6:
                        off += snprintf(buf + off, BUFFER_SIZE - off, "Tune Request");
                        break;

                default:
                        free(buf);
                        return (NULL);
        }

        assert (off <= BUFFER_SIZE);
        return (buf);
}

static void
note_from_int(char *buf, int note_number)
{
        int note, octave;
        const char *names[] = {"C", "C#", "D", "D#", "E", "F", "F#", "G", "G#", "A", "A#", "B"};

        octave = note_number / 12 - 1;
        note = note_number % 12;

        sprintf(buf, "%s%d", names[note], octave);
}

char *
smf_event_decode(const smf_event_t *event)
{
        int off = 0, channel;
        char *buf, note[5];

        if (smf_event_is_metadata(event))
                return (smf_event_decode_metadata(event));

        if (smf_event_is_system_realtime(event))
                return (smf_event_decode_system_realtime(event));

        if (smf_event_is_system_common(event))
                return (smf_event_decode_system_common(event));

        if (!smf_event_length_is_valid(event)) {
                g_critical("smf_event_decode: incorrect MIDI message length.");
                return (NULL);
        }

        buf = (char*)malloc(BUFFER_SIZE);
        if (buf == NULL) {
                g_critical("smf_event_decode: malloc failed.");
                return (NULL);
        }

        /* + 1, because user-visible channels used to be in range <1-16>. */
        channel = (event->midi_buffer[0] & 0x0F) + 1;

        switch (event->midi_buffer[0] & 0xF0) {
                case 0x80:
                        note_from_int(note, event->midi_buffer[1]);
                        off += snprintf(buf + off, BUFFER_SIZE - off, "Note Off, channel %d, note %s, velocity %d",
                                        channel, note, event->midi_buffer[2]);
                        break;

                case 0x90:
                        note_from_int(note, event->midi_buffer[1]);
                        off += snprintf(buf + off, BUFFER_SIZE - off, "Note On, channel %d, note %s, velocity %d",
                                        channel, note, event->midi_buffer[2]);
                        break;

                case 0xA0:
                        note_from_int(note, event->midi_buffer[1]);
                        off += snprintf(buf + off, BUFFER_SIZE - off, "Aftertouch, channel %d, note %s, pressure %d",
                                        channel, note, event->midi_buffer[2]);
                        break;

                case 0xB0:
                        off += snprintf(buf + off, BUFFER_SIZE - off, "Controller, channel %d, controller %d, value %d",
                                        channel, event->midi_buffer[1], event->midi_buffer[2]);
                        break;

                case 0xC0:
                        off += snprintf(buf + off, BUFFER_SIZE - off, "Program Change, channel %d, controller %d",
                                        channel, event->midi_buffer[1]);
                        break;

                case 0xD0:
                        off += snprintf(buf + off, BUFFER_SIZE - off, "Channel Pressure, channel %d, pressure %d",
                                        channel, event->midi_buffer[1]);
                        break;

                case 0xE0:
                        off += snprintf(buf + off, BUFFER_SIZE - off, "Pitch Wheel, channel %d, value %d",
                                        channel, ((int)event->midi_buffer[2] << 7) | (int)event->midi_buffer[2]);
                        break;

                default:
                        free(buf);
                        return (NULL);
        }

        assert(off <= BUFFER_SIZE);

        return (buf);
}

char *
smf_decode(const smf_t *smf)
{
        int off = 0;
        char *buf;

        buf = (char*)malloc(BUFFER_SIZE);
        if (buf == NULL) {
                g_critical("smf_event_decode: malloc failed.");
                return (NULL);
        }

        off += snprintf(buf + off, BUFFER_SIZE - off, "format: %d ", smf->format);

        switch (smf->format) {
                case 0:
                        off += snprintf(buf + off, BUFFER_SIZE - off, "(single track)");
                        break;

                case 1:
                        off += snprintf(buf + off, BUFFER_SIZE - off, "(several simultaneous tracks)");
                        break;

                case 2:
                        off += snprintf(buf + off, BUFFER_SIZE - off, "(several independent tracks)");
                        break;

                default:
                        off += snprintf(buf + off, BUFFER_SIZE - off, "(INVALID FORMAT)");
                        break;
        }

        off += snprintf(buf + off, BUFFER_SIZE - off, "; number of tracks: %d", smf->number_of_tracks);

        if (smf->ppqn != 0)
                off += snprintf(buf + off, BUFFER_SIZE - off, "; division: %d PPQN", smf->ppqn);
        else
                off += snprintf(buf + off, BUFFER_SIZE - off, "; division: %d FPS, %d resolution", smf->frames_per_second, smf->resolution);

        assert (off <= BUFFER_SIZE);
        return (buf);
}