/*
 *** midtotxt.c: SMF ファイルをテキスト形式に変換する ***
 *		(1999.8.12: YH)
 *		(1999.8.17 (revised))
 *		(2017.10.31 (revised))
 *
 * * 使用法： midtotxt [-options] [SMF-file]
 *   出力は stdout へ。
 * * options
 *   b: バイト情報のみを出力
 *   n: ノート情報のみを出力
 *
 *** このプログラムはあくまで SMF ファイルのバイト列を可視化するだけの
 *   ものであり、実用的価値は低い（PMML の逆コンパイラなどを利用すること）。
 * * 入力の MIDI ファイルにはエラーはないものとし、ファイル内容についての
 *   エラー処理は省略してある。
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/* option flags */
int byteflag = 0;		/* 1 ならバイト情報のみを出力 */
int noteflag = 0;		/* 1 ならノート情報のみを出力 */

#define	MAXLEN	1000000		/* SMF ファイル読み込みバッファの大きさ */

int format;			/* フォーマット： 0/1/2 */
int tracks;			/* トラック数 */
int tqtm;			/* 時間単位 */

int ntrack;			/* 現在のトラック番号 (0, 1, 2, ...) */
int ttime;			/* 現在のトラック中の通算時間 */
int delta;			/* イベントのデルタ・タイム */
int status;			/* イベントのステータス・バイト */
int start;			/* イベント（ないしチャンク）の先頭バイト */
int trackbytes;			/* トラック・データセクションのバイト数 */
int events;			/* 総イベント数 */
int tevents;			/* トラックのイベント数 */

/*
 *** mid ファイル読み込み ***
 */

FILE *fin;
char filename[100];		/* 入力 SMF ファイル名 */
unsigned char mbuf[MAXLEN];	/* SMF ファイル読み込みバッファ */
int mlen;			/* SMF ファイルの長さ（バイト数） */
int mp;				/* 現在のバイト位置 */

void
readfile()			/* SMF ファイルを内部バッファに読み込む */
{
	int c;
	mlen = 0;
	while ((c = getc(fin)) != EOF) {
		if (mlen >= MAXLEN) {
			fprintf(stderr, "*** SMF file too large ***\n");
			exit(1);
		}
		mbuf[mlen++] = c;
	}
	mp = 0;
}

/*
 *** 数値入力 ***
 */

#define	getb()		mbuf[mp++]	/* １バイトの読み込み */
#define	ungetb()	mp--

int
getn(b)				/* 固定長数値の読み込み b: バイト数 */
	int b;
{
	int n, i;
	for (i=0, n=0; i<b; i++) {
		n = (n << 8) | getb();
	}
	return(n);
}

int
getv()				/* 可変長数値の読み込み */
{
	int c, n = 0;
	do {
		c = getb();
		n = (n << 7) | (c & 0x7f);
	} while(c & 0x80);
	return(n);
}

/*
 *** putheader(): ヘッダ行（カウンタ情報、バイト列）の出力 ***
 */

int runstatus = 0;		/* running status の場合のバイト値 (MIDI event) */

void
putheader(from, to, chunkflag, textflag)
	int from, to, chunkflag, textflag;
{
	int i;
	int xto = (textflag)? textflag: to;

	printf("%05d", start);
	if (chunkflag) {
		printf(" --------- ------ [\"%c%c%c%c\" ",
			mbuf[from], mbuf[from+1], mbuf[from+2], mbuf[from+3]);
		from += 4;
	} else {
		printf(" %02d:%06d %06d [", ntrack, ttime, delta);
		/* デルタ・タイム部 */
		for (i=from;; i++) {
			if (i > from) printf(" ");
			printf("%02x", mbuf[i]);
			if ((mbuf[i] & 0x80) == 0) break;
		}
		from = i+1;
		printf("]+");
		if (runstatus) printf("<%02x>+", runstatus);
		printf("[");
	}
	for (i=from; i<xto; i++) {
		if (i > from) printf(" ");
		printf("%02x", mbuf[i]);
	}
	if (textflag) {
		printf(" \"");
		for (i=xto; i<to; i++) printf("%c", mbuf[i]);
		printf("\"");
	}
	printf("]\n");
}

/*
 *** HeaderChunk(): ヘッダ・チャンクの読み込み・表示 ***
 */

void
HeaderChunk()
{
	int len;

	start = mp;
	if (strncmp((char *)(mbuf+mp), "MThd", 4)) { /* first 4 bytes are "MThd"? */
		/* error: shouldn't happen */
	}
	mp += 4;
	len = getn(4);
	if (len != 6) {
		/* error: shouldn't happen */
	}

	format = getn(2);
	if ((format < 0) || (format > 2)) {
		/* error: shouldn't happen */
	}

	tracks = getn(2);	/* error check omitted */

	tqtm = getn(2);		/* error check omitted */

	putheader(start, mp, 1, 0);
	if (byteflag) return;
	printf("\t\t*** Header Chunk ***\n");
	printf("\t\t    Format      : %d\n", format);
	printf("\t\t    # of Tracks : %d\n", tracks);
	printf("\t\t    Time quantum: %d\n", tqtm);
	printf("\n");
}

/*
 *** トラック読み込み ***
 */

static int textflag;
static char obuf[1000];
static int op;

void
event_error()				/* 解析不能イベント：異常終了 */
{
	putheader(start, start+10, 0, 0);
	printf("\t*** unknown event, aborting ***\n");
	exit(1);
}

static char *notenames[12] = {		/* 音名（note-number % 12) */
	"C    ",
	"C#/Db",
	"D    ",
	"D#/Eb",
	"E    ",
	"F    ",
	"F#/Gb",
	"G    ",
	"G#/Ab",
	"A    ",
	"A#/Bb",
	"B    ",
};

#define	print_note(note) \
	op += sprintf(obuf+op, " [%d%s]", note/12-1, notenames[note % 12])

#define	Controlmsg(str)	\
	op += sprintf(obuf+op, " (%s (%s))", str, (d1 & 0x20)? "LSB": "MSB")

void
Control_event(d1, d2)		/* control change (0xBx) メッセージの詳細 */
	int d1, d2;
{
	switch(d1) {
		case 0x00: case 0x20: Controlmsg("bank select");	break;
		case 0x01: case 0x21: Controlmsg("modulation");		break;
		case 0x02: case 0x22: Controlmsg("breath control");	break;
		case 0x04: case 0x24: Controlmsg("foot control");	break;
		case 0x05: case 0x25: Controlmsg("portamento time");	break;
		case 0x06: case 0x26: Controlmsg("data entry");		break;
		case 0x07: case 0x27: Controlmsg("main volume");	break;
		case 0x08: case 0x28: Controlmsg("balance control");	break;
		case 0x0a: case 0x2a: Controlmsg("panpot");		break;
		case 0x0b: case 0x2b: Controlmsg("expression");		break;

		case 0x0c:
			op += sprintf(obuf+op, " (effect control (KORG))");
			break;
		case 0x0d:
			op += sprintf(obuf+op, " (effect control (KORG))");
			break;

		case 0x40:
			op += sprintf(obuf+op, " (hold 1 (damper) on/off)");
			break;
		case 0x41:
			op += sprintf(obuf+op, " (portamento)");
			break;
		case 0x42:
			op += sprintf(obuf+op, " (sostenuto)");
			break;
		case 0x43:
			op += sprintf(obuf+op, " (soft)");
			break;
		case 0x45:
			op += sprintf(obuf+op, " (hold 2 (freeze))");
			break;
		case 0x48:
			op += sprintf(obuf+op, " (release time (KORG))");
			break;
		case 0x49:
			op += sprintf(obuf+op, " (attack time (KORG))");
			break;
		case 0x4a:
			op += sprintf(obuf+op, " (brightness (KORG))");
			break;
		case 0x54:
			op += sprintf(obuf+op, " (portamento control (Roland))");
			break;
		case 0x5b:
			op += sprintf(obuf+op, " (external effect depth)");
			break;
		case 0x5c:
			op += sprintf(obuf+op, " (tremolo depth)");
			break;
		case 0x5d:
			op += sprintf(obuf+op, " (chorus depth)");
			break;
		case 0x5e:
			op += sprintf(obuf+op, " (celeste depth)");
			break;
		case 0x5f:
			op += sprintf(obuf+op, " (phaser depth)");
			break;

		case 0x60:
			op += sprintf(obuf+op, " (data increment)");
			break;
		case 0x61:
			op += sprintf(obuf+op, " (data decrement)");
			break;
		case 0x62:
			op += sprintf(obuf+op, " (NRPN LSB)");
			break;
		case 0x63:
			op += sprintf(obuf+op, " (NRPN MSB)");
			break;
		case 0x64:
			op += sprintf(obuf+op, " (RPN LSB)");
			break;
		case 0x65:
			op += sprintf(obuf+op, " (RPN MSB)");
			break;
		case 0x78:
			op += sprintf(obuf+op, " (all sound off)");
			break;
		case 0x79:
			op += sprintf(obuf+op, " (reset all controllers)");
			break;
		case 0x7a:
			op += sprintf(obuf+op, " (local control)");
			break;
		case 0x7b:
			op += sprintf(obuf+op, " (all notes off)");
			break;
		case 0x7c:
			op += sprintf(obuf+op, " (omni mode off)");
			break;
		case 0x7d:
			op += sprintf(obuf+op, " (omni mode on)");
			break;
		case 0x7e:
			op += sprintf(obuf+op, " (mono mode on)");
			break;
		case 0x7f:
			op += sprintf(obuf+op, " (poly mode on)");
			break;
		default: break;
	}
}

void
MIDI_event()
{
	int message, channel, d1, d2;

	op += sprintf(obuf+op, "\t\t<MIDI>  ");
	message = status & 0xf0;
	channel = status & 0x0f;

	switch(message) {
		case 0x80:			/* note off */
			d1 = getn(1); d2 = getn(1);
			op += sprintf(obuf+op, "#%02d note off %3d %3d",
				channel, d1, d2);
			print_note(d1);
			break;
		case 0x90:			/* note on */
			d1 = getn(1); d2 = getn(1);
			op += sprintf(obuf+op, "#%02d note on  %3d %3d",
				channel, d1, d2);
			print_note(d1);
			break;
		case 0xa0:			/* polyphonic key pressure */
			d1 = getn(1); d2 = getn(1);
			op += sprintf(obuf+op, "#%02d poly. key pressure %3d %3d",
				channel, d1, d2);
			print_note(d1);
			break;
		case 0xb0:			/* control change */
			d1 = getn(1); d2 = getn(1);
			op += sprintf(obuf+op, "#%02d control change %3d %3d",
				channel, d1, d2);
			/* 個別内容については以下で追記出力 */
			Control_event(d1, d2);
			break;
		case 0xc0:			/* program change */
			d1 = getn(1);
			op += sprintf(obuf+op, "#%02d program change %d",
				channel, d1);
			break;
		case 0xd0:			/* channel pressure */
			d1 = getn(1);
			op += sprintf(obuf+op, "#%02d channel pressure %d",
				channel, d1);
			break;
		case 0xe0:			/* pitch bend */
			d1 = getn(1); d2 = getn(1);
			op += sprintf(obuf+op, "#%02d pitch bend %d",
				channel, ((d2 << 7) | d1)-0x2000);
			break;
		case 0xf0:
			switch(channel) {
				/* common messages */
				case 0x01:
					d1 = getn(1);
					op += sprintf(obuf+op, "quarter frame %d", d1);
					break;
				case 0x02:
					d1 = getn(1); d2 = getn(1);
					d1 |= d2 << 7;
					op += sprintf(obuf+op,
						"song position pointer %d", d1);
					break;
				case 0x03:
					d1 = getn(1);
					op += sprintf(obuf+op, "song select %d", d1);
					break;
				case 0x06:
					op += sprintf(obuf+op, "tune request");
					break;

				/* real-time messages */
				case 0x08:
					op += sprintf(obuf+op, "timing clock");
					break;
				case 0x0a:
					op += sprintf(obuf+op, "start");
					break;
				case 0x0b:
					op += sprintf(obuf+op, "continue");
					break;
				case 0x0c:
					op += sprintf(obuf+op, "stop");
					break;
				case 0x0e:
					op += sprintf(obuf+op, "active sensing");
					break;

				default:
					event_error();
			}
			break;
		default:
			event_error();	/* shouldn't happen */
	}

	if (runstatus) {
		op += sprintf(obuf+op, " *");
	}
	op += sprintf(obuf+op, "\n");
}

void
SysEx_event()
{
	int len = getv();

	op += sprintf(obuf+op, "\t\t<SysEx> system exclusive\n");
	mp += len;
}

static char *sharpkey[8][2] = {		/* 調名：嬰（シャープ）系 */
	{ "C major", "A minor" },
	{ "G major", "E minor" },
	{ "D major", "B minor" },
	{ "A major", "F# minor" },
	{ "E major", "C# minor" },
	{ "B major", "G# minor" },
	{ "F# major", "D# minor" },
	{ "C# major", "A# minor" },
};

static char *flatkey[8][2] = {		/* 調名：変（フラット）系 */
	{ "C major", "A minor" },
	{ "F major", "D minor" },
	{ "Bb major", "G minor" },
	{ "Eb major", "C minor" },
	{ "Ab major", "F minor" },
	{ "Db major", "Bb minor" },
	{ "Gb major", "Eb minor" },
	{ "Cb major", "Ab minor" },
};

void
Meta_event()
{
	int n, event_type;

	op += sprintf(obuf+op, "\t\t<Meta>  ");
	switch(event_type = getb()) {
		case 0x00:
			if (getb() != 0x02) event_error();
			op += sprintf(obuf+op, "sequence number: %d\n", getn(2));
			break;
		case 0x01:
			op += sprintf(obuf+op, "text");
			goto TEXT;
		case 0x02:
			op += sprintf(obuf+op, "copyright notice");
			goto TEXT;
		case 0x03:
			op += sprintf(obuf+op, "sequence/track name");
			goto TEXT;
		case 0x04:
			op += sprintf(obuf+op, "instrument name");
			goto TEXT;
		case 0x05:
			op += sprintf(obuf+op, "lyric");
			goto TEXT;
		case 0x06:
			op += sprintf(obuf+op, "marker");
			goto TEXT;
		case 0x07:
			op += sprintf(obuf+op, "cue point");
		case 0x08: case 0x09: case 0x0a: case 0x0b:
		case 0x0c: case 0x0d: case 0x0e: case 0x0f:
			op += sprintf(obuf+op, "other texts");
		TEXT:
			n = getv();
			textflag = mp;
			op += sprintf(obuf+op, " (%d bytes)\n", n);
			mp += n;
			break;

		case 0x20:
		case 0x21:	/* patch */
			if (getb() != 0x01) event_error();
			op += sprintf(obuf+op, "MIDI channel prefix: %d\n", getn(1));
			break;
		case 0x2f:
			if (getb() != 0x00) event_error();
			op += sprintf(obuf+op, "end of track (%d events)\n", tevents);
			break;
		case 0x51:
			if (getb() != 0x03) event_error();
			op += sprintf(obuf+op, "set tempo: %d\n", getn(3));
			break;
		case 0x54:
			if (getb() != 0x05) event_error();
			op += sprintf(obuf+op, "SMPTE offset");
			n = getn(1);
			op += sprintf(obuf+op, " %d - %02d", n >> 5, n & 0x1f);
			n = getn(1);
			op += sprintf(obuf+op, ":%02d", n);
			n = getn(1);
			op += sprintf(obuf+op, ":%02d", n);
			n = getn(1);
			op += sprintf(obuf+op, ".%02d", n);
			n = getn(1);
			op += sprintf(obuf+op, " %3d\n", n);
			break;
		case 0x58:
			if (getb() != 0x04) event_error();
			op += sprintf(obuf+op, "time signature:");
			n = getn(1);
			op += sprintf(obuf+op, " %d", n);
			n = getn(1);
			op += sprintf(obuf+op, "/%d", 1 << n);
			n = getn(1);
			op += sprintf(obuf+op, "  %d", n);
			n = getn(1);
			op += sprintf(obuf+op, "  %d\n", n);
			break;
		case 0x59:
			if (getb() != 0x02) event_error();
			op += sprintf(obuf+op, "key signature:");
			n = getn(1);
			if (n & 0x80) {
				n = 0x100 - n;
				op += sprintf(obuf+op, " %s\n",
					flatkey[n][getn(1)]);
			} else {
				op += sprintf(obuf+op, " %s\n", sharpkey[n][getn(1)]);
			}
			break;
		case 0x7f:
			n = getv();
			sprintf(obuf+op, "sequencer specific (%d bytes)\n", n);
			mp += n;
			break;
		default:
			event_error();
	}
}


void
get_event()			/* イベント１コの処理 */
{
	int b, savstatus;

	start = mp;
	textflag = 0;
	op = 0;
	runstatus = 0;
	tevents++;

	delta = getv();
	ttime += delta;

	b = getb();
	if (b & 0x80) {
		savstatus = status;
		switch(status = b) {
			default:
				MIDI_event();
				if (status >= 0xf8) status = savstatus;
				break;
			case 0xf0: case 0xf7:
				SysEx_event();
				break;
			case 0xff:
				Meta_event();
				status = savstatus;
				break;
		}
	} else {	/* running status */
		ungetb();
		runstatus = status;
		MIDI_event();
	}

	b = status & 0xf0;
	if (noteflag && (b != 0x80) && (b != 0x90)) return;
	putheader(start, mp, 0, textflag);
	if (byteflag) return;
	printf("%s", obuf);
}

void
TrackChunk()			/* トラック・チャンク処理 */
{
	int endtrack;
	start = mp;
	ttime = 0;
	tevents = 0;

	/* header part */
	if (strncmp((char *)(mbuf+mp), "MTrk", 4)) { /* first 4 bytes are "MTrk"? */
		/* error: shouldn't happen */
	}
	mp += 4;
	trackbytes = getn(4);
	endtrack = mp + trackbytes;

	putheader(start, mp, 1, 0);
	if (!byteflag)
		printf("\t\t*** Track Chunk %d (%d bytes) ***\n\n",
			ntrack, trackbytes);

	while (mp < endtrack) get_event();
	events += tevents;
	if (!byteflag) printf("\n");
}

/*
 *** トップレベル ***
 */
void
main(argc, argv)
	int argc; char **argv;
{
	int i, j;

	fin = stdin;
	strcpy(filename, "(stdin)");

	for (i=1; i<argc; i++) {
		if (argv[i][0] == '-') {
			for (j=1; argv[i][j]; j++) switch(argv[i][j]) {
				case 'b': byteflag = 1; break;
				case 'n': noteflag = 1; break;
			}
		} else {
			strcpy(filename, argv[i]);
			if ((fin = fopen(filename, "r")) == NULL) {
				fprintf(stderr, "%s: can't open", filename);
				exit(1);
			}
		}
	}
	if (!byteflag) printf("\t\t*** Input file name: %s\n", filename);

	readfile();
	HeaderChunk();

	events = 0;
	for (ntrack = 0; ntrack < tracks; ntrack++) TrackChunk();

	if (!byteflag) printf("\t\t*** (%d bytes, %d events) ***\n\n", mlen, events);
}