nuclear@0: #include <stdio.h>
nuclear@0: #include <stdlib.h>
nuclear@0: #include <string.h>
nuclear@0: #include <errno.h>
nuclear@0: #include <inttypes.h>
nuclear@0: #include <unistd.h>
nuclear@0: #include <fcntl.h>
nuclear@0: #include <sys/mman.h>
nuclear@0: #include <sys/stat.h>
nuclear@0: #include <arpa/inet.h>
nuclear@0: #include "midi.h"
nuclear@0: 
nuclear@0: #define FMT_SINGLE		0
nuclear@0: #define FMT_MULTI_TRACK	1
nuclear@0: #define FMT_MULTI_SEQ	2
nuclear@0: 
nuclear@0: /* meta events */
nuclear@0: #define META_SEQ		0
nuclear@0: #define META_TEXT		1
nuclear@0: #define META_COPYRIGHT	2
nuclear@0: #define META_NAME		3
nuclear@0: #define META_INSTR		4
nuclear@0: #define META_LYRICS		5
nuclear@0: #define META_MARKER		6
nuclear@0: #define META_CUE		7
nuclear@0: #define META_CHANPREFIX	32
nuclear@0: #define META_END_TRACK	47
nuclear@0: #define META_TEMPO		81
nuclear@0: #define META_SMPTE_OFFS	84
nuclear@0: #define META_TMSIG		88
nuclear@0: #define META_KEYSIG		89
nuclear@0: #define META_SPECIFIC	127
nuclear@0: 
nuclear@0: struct midi {
nuclear@0: 	int bpm;
nuclear@0: 
nuclear@0: 	int num_tracks;
nuclear@0: 	struct midi_track *tracks;
nuclear@0: };
nuclear@0: 
nuclear@0: struct midi_track {
nuclear@0: 	char *name;
nuclear@0: 	struct midi_event *head, *tail;
nuclear@0: 	int num_ev;
nuclear@0: };
nuclear@0: 
nuclear@0: struct midi_event {
nuclear@0: 	long dt;
nuclear@0: 	int type;
nuclear@0: 	int channel;
nuclear@0: 	int arg[2];
nuclear@0: 
nuclear@0: 	struct midi_event *next;
nuclear@0: };
nuclear@0: 
nuclear@0: #define CHUNK_HDR_SIZE	8
nuclear@0: struct chunk_hdr {
nuclear@0: 	char id[4];
nuclear@0: 	uint32_t size;
nuclear@0: 	unsigned char data[1];
nuclear@0: };
nuclear@0: 
nuclear@0: struct midi_hdr {
nuclear@0: 	uint16_t fmt;	/* 0: single, 1: multi-track, 2: multiple independent */
nuclear@0: 	uint16_t num_tracks;
nuclear@0: 	uint16_t tm_div;
nuclear@0: 
nuclear@0: } __attribute__ ((packed));
nuclear@0: 
nuclear@0: static void destroy_track(struct midi_track *trk);
nuclear@0: static int read_track(struct midi *midi, struct chunk_hdr *chunk);
nuclear@0: static long read_vardata(unsigned char **pptr);
nuclear@0: static int read_meta_event(struct midi *midi, struct midi_track *trk, unsigned char **pptr);
nuclear@0: static int read_sysex_event(struct midi *midi, unsigned char **pptr);
nuclear@0: static int ischunk(struct chunk_hdr *chunk, const char *name);
nuclear@0: static struct chunk_hdr *mkchunk(void *ptr);
nuclear@0: static struct chunk_hdr *skip_chunk(struct chunk_hdr *chunk);
nuclear@0: static struct midi_hdr *mkmidi(void *ptr);
nuclear@0: static void bigend(void *ptr, int sz);
nuclear@0: static void *map_file(const char *fname, int *size);
nuclear@0: static void unmap_file(void *mem, int size);
nuclear@0: 
nuclear@0: #define IS_VALID_EVTYPE(x) ((x) >= MIDI_NOTE_OFF && (x) <= MIDI_PITCH_BEND)
nuclear@0: 
nuclear@0: /* XXX the event arity table must match the MIDI_* defines in midi.h */
nuclear@0: static int ev_arity[] = {
nuclear@0: 	0, 0, 0, 0, 0, 0, 0, 0,
nuclear@0: 	2, /* note off (note, velocity)*/
nuclear@0: 	2, /* note on (note, velocity)*/
nuclear@0: 	2, /* note aftertouch (note, aftertouch value) */
nuclear@0: 	2, /* controller (controller number, value) */
nuclear@0: 	1, /* prog change (prog number) */
nuclear@0: 	1, /* channel aftertouch (aftertouch value) */
nuclear@0: 	2  /* pitch bend (pitch LSB, pitch MSB) */
nuclear@0: };
nuclear@0: 
nuclear@0: 
nuclear@0: struct midi *load_midi(const char *fname)
nuclear@0: {
nuclear@0: 	struct midi *midi;
nuclear@0: 	char *mem;
nuclear@0: 	int size;
nuclear@0: 	struct chunk_hdr *chunk;
nuclear@0: 	struct midi_hdr *hdr;
nuclear@0: 
nuclear@0: 	if(!(mem = map_file(fname, &size))) {
nuclear@0: 		return 0;
nuclear@0: 	}
nuclear@0: 	chunk = mkchunk(mem);
nuclear@0: 
nuclear@0: 	if(!ischunk(chunk, "MThd") || chunk->size != 6) {
nuclear@0: 		fprintf(stderr, "invalid or corrupted midi file: %s\n", fname);
nuclear@0: 		goto end;
nuclear@0: 	}
nuclear@0: 	hdr = mkmidi(chunk->data);
nuclear@0: 
nuclear@0: 	printf("format: %d\n", (int)hdr->fmt);
nuclear@0: 	printf("tracks: %d\n", (int)hdr->num_tracks);
nuclear@0: 
nuclear@0: 	if((hdr->tm_div & 0x8000) == 0) {
nuclear@0: 		/* division is in pulses / quarter note */
nuclear@0: 		printf("time division: %d ppqn\n", (int)hdr->tm_div);
nuclear@0: 	} else {
nuclear@0: 		/* division in frames / sec */
nuclear@0: 		int fps = (hdr->tm_div & 0x7f00) >> 8;
nuclear@0: 		int ticks_per_frame = hdr->tm_div & 0xff;
nuclear@0: 		printf("time division: %d fps, %d ticks/frame\n", fps, ticks_per_frame);
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	if(!(midi = malloc(sizeof *midi))) {
nuclear@0: 		perror("failed to allocate memory");
nuclear@0: 		goto end;
nuclear@0: 	}
nuclear@0: 	if(!(midi->tracks = malloc(hdr->num_tracks * sizeof *midi->tracks))) {
nuclear@0: 		perror("failed to allocate memory");
nuclear@0: 		goto end;
nuclear@0: 	}
nuclear@0: 	midi->num_tracks = 0;
nuclear@0: 
nuclear@0: 	while((chunk = skip_chunk(chunk))) {
nuclear@0: 		if(ischunk(chunk, "MTrk")) {
nuclear@0: 			if(read_track(midi, chunk) == -1) {
nuclear@0: 				fprintf(stderr, "failed to read track\n");
nuclear@0: 			}
nuclear@0: 		} else {
nuclear@0: 			printf("ignoring chunk: %c%c%c%c\n", chunk->id[0], chunk->id[1], chunk->id[2], chunk->id[3]);
nuclear@0: 		}
nuclear@0: 	}
nuclear@0: 
nuclear@0: end:
nuclear@0: 	unmap_file(mem, size);
nuclear@0: 	if(midi) {
nuclear@0: 		free_midi(midi);
nuclear@0: 		midi = 0;
nuclear@0: 	}
nuclear@0: 	return midi;
nuclear@0: }
nuclear@0: 
nuclear@0: void free_midi(struct midi *midi)
nuclear@0: {
nuclear@0: 	int i;
nuclear@0: 
nuclear@0: 	if(!midi) return;
nuclear@0: 
nuclear@0: 	for(i=0; i<midi->num_tracks; i++) {
nuclear@0: 		destroy_track(midi->tracks + i);
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	free(midi->tracks);	/* TODO free tracks properly */
nuclear@0: 	free(midi);
nuclear@0: }
nuclear@0: 
nuclear@0: static void destroy_track(struct midi_track *trk)
nuclear@0: {
nuclear@0: 	free(trk->name);
nuclear@0: 	while(trk->head) {
nuclear@0: 		void *tmp = trk->head;
nuclear@0: 		trk->head = trk->head->next;
nuclear@0: 		free(tmp);
nuclear@0: 	}
nuclear@0: }
nuclear@0: 
nuclear@0: static int read_track(struct midi *midi, struct chunk_hdr *chunk)
nuclear@0: {
nuclear@0: 	unsigned char *ptr;
nuclear@0: 	struct midi_track trk = {0, 0, 0, 0};
nuclear@0: 
nuclear@0: 	if(!ischunk(chunk, "MTrk")) {
nuclear@0: 		return -1;
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	ptr = chunk->data;
nuclear@0: 	while(ptr < chunk->data + chunk->size) {
nuclear@0: 		long dt;
nuclear@0: 		unsigned char stat;
nuclear@0: 
nuclear@0: 		/* TODO also convert dt to some standard unit */
nuclear@0: 		dt = read_vardata(&ptr);
nuclear@0: 		stat = *ptr++;
nuclear@0: 
nuclear@0: 		if(stat == 0xff) {
nuclear@0: 			read_meta_event(midi, &trk, &ptr);
nuclear@0: 		} else if(stat == 0xf0) {
nuclear@0: 			read_sysex_event(midi, &ptr);
nuclear@0: 		} else {
nuclear@0: 			struct midi_event *ev = malloc(sizeof *ev);
nuclear@0: 
nuclear@0: 			if(trk.head) {
nuclear@0: 				trk.tail->next = ev;
nuclear@0: 			} else {
nuclear@0: 				trk.head = ev;
nuclear@0: 			}
nuclear@0: 			trk.tail = ev;
nuclear@0: 			ev->next = 0;
nuclear@0: 			trk.num_ev++;
nuclear@0: 
nuclear@0: 			ev->dt = dt;
nuclear@0: 			ev->type = (stat >> 4) & 0xf;
nuclear@0: 			if(!IS_VALID_EVTYPE(ev->type)) {
nuclear@0: 				fprintf(stderr, "warning, skipping track with unknown event %d\n", ev->type);
nuclear@0: 				return -1;
nuclear@0: 			}
nuclear@0: 			ev->channel = stat & 0xf;
nuclear@0: 
nuclear@0: 			ev->arg[0] = *ptr++;
nuclear@0: 			if(ev_arity[ev->type] > 1) {
nuclear@0: 				ev->arg[1] = *ptr++;
nuclear@0: 			}
nuclear@0: 		}
nuclear@0: 	}
nuclear@0: 
nuclear@0: 	/* if we did actually add any events ... */
nuclear@0: 	if(trk.num_ev) {
nuclear@0: 		midi->tracks[midi->num_tracks++] = trk;
nuclear@0: 	}
nuclear@0: 	return 0;
nuclear@0: }
nuclear@0: 
nuclear@0: static long read_vardata(unsigned char **pptr)
nuclear@0: {
nuclear@0: 	int i;
nuclear@0: 	long res = 0;
nuclear@0: 	unsigned char *ptr = *pptr;
nuclear@0: 
nuclear@0: 	for(i=0; i<4; i++) {
nuclear@0: 		res |= (long)(*ptr & 0x7f) << (i * 8);
nuclear@0: 
nuclear@0: 		/* if first bit is not set we're done */
nuclear@0: 		if((*ptr++ & 0x80) == 0)
nuclear@0: 			break;
nuclear@0: 	}
nuclear@0: 	*pptr = ptr;
nuclear@0: 	return res;
nuclear@0: }
nuclear@0: 
nuclear@0: static int read_meta_event(struct midi *midi, struct midi_track *trk, unsigned char **pptr)
nuclear@0: {
nuclear@0: 	unsigned char *ptr = *pptr;
nuclear@0: 	unsigned char type;
nuclear@0: 	long size;
nuclear@0: 
nuclear@0: 	type = *ptr++;
nuclear@0: 	size = read_vardata(&ptr);
nuclear@0: 
nuclear@0: 	switch(type) {
nuclear@0: 	case META_NAME:
nuclear@0: 		free(trk->name);
nuclear@0: 		trk->name = malloc(size + 1);
nuclear@0: 		memcpy(trk->name, ptr, size);
nuclear@0: 		trk->name[size] = 0;
nuclear@0: 		break;
nuclear@0: 
nuclear@0: 	case META_TEMPO:
nuclear@0: 		/* TODO add a tempo change event to the midi struct */
nuclear@0: 		break;
nuclear@0: 
nuclear@0: 	default:
nuclear@0: 		break;
nuclear@0: 	}
nuclear@0: 	*pptr = ptr + size;
nuclear@0: 	return 0;
nuclear@0: }
nuclear@0: 
nuclear@0: /* ignore sysex events */
nuclear@0: static int read_sysex_event(struct midi *midi, unsigned char **pptr)
nuclear@0: {
nuclear@0: 	long size = read_vardata(pptr);
nuclear@0: 	*pptr += size;
nuclear@0: 	return 0;
nuclear@0: }
nuclear@0: 
nuclear@0: static int ischunk(struct chunk_hdr *chunk, const char *name)
nuclear@0: {
nuclear@0: 	return memcmp(chunk->id, name, 4) == 0;
nuclear@0: }
nuclear@0: 
nuclear@0: static struct chunk_hdr *mkchunk(void *ptr)
nuclear@0: {
nuclear@0: 	struct chunk_hdr *chdr = ptr;
nuclear@0: 	bigend(&chdr->size, sizeof chdr->size);
nuclear@0: 	return chdr;
nuclear@0: }
nuclear@0: 
nuclear@0: static struct chunk_hdr *skip_chunk(struct chunk_hdr *chunk)
nuclear@0: {
nuclear@0: 	return mkchunk((char*)chunk + CHUNK_HDR_SIZE + chunk->size);
nuclear@0: }
nuclear@0: 
nuclear@0: static struct midi_hdr *mkmidi(void *ptr)
nuclear@0: {
nuclear@0: 	struct midi_hdr *midi = ptr;
nuclear@0: 
nuclear@0: 	bigend(&midi->fmt, sizeof midi->fmt);
nuclear@0: 	bigend(&midi->num_tracks, sizeof midi->num_tracks);
nuclear@0: 	bigend(&midi->tm_div, sizeof midi->tm_div);
nuclear@0: 	return midi;
nuclear@0: }
nuclear@0: 
nuclear@0: static void bigend(void *ptr, int sz)
nuclear@0: {
nuclear@0: 	switch(sz) {
nuclear@0: 	case 4:
nuclear@0: 		*((uint32_t*)ptr) = ntohl(*(uint32_t*)ptr);
nuclear@0: 		break;
nuclear@0: 
nuclear@0: 	case 2:
nuclear@0: 		*(uint16_t*)ptr = ntohs(*(uint16_t*)ptr);
nuclear@0: 		break;
nuclear@0: 
nuclear@0: 	case 1:
nuclear@0: 	default:
nuclear@0: 		break;
nuclear@0: 	}
nuclear@0: }
nuclear@0: 
nuclear@0: static void *map_file(const char *fname, int *size)
nuclear@0: {
nuclear@0: 	int fd;
nuclear@0: 	struct stat st;
nuclear@0: 	void *mem;
nuclear@0: 
nuclear@0: 	if((fd = open(fname, O_RDONLY)) == -1) {
nuclear@0: 		fprintf(stderr, "failed to open midi file: %s: %s\n", fname, strerror(errno));
nuclear@0: 		return 0;
nuclear@0: 	}
nuclear@0: 	fstat(fd, &st);
nuclear@0: 
nuclear@0: 	if((mem = mmap(0, st.st_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0)) == (void*)-1) {
nuclear@0: 		fprintf(stderr, "failed to map midi file: %s: %s\n", fname, strerror(errno));
nuclear@0: 		close(fd);
nuclear@0: 		return 0;
nuclear@0: 	}
nuclear@0: 	close(fd);
nuclear@0: 
nuclear@0: 	*size = st.st_size;
nuclear@0: 	return mem;
nuclear@0: }
nuclear@0: 
nuclear@0: static void unmap_file(void *mem, int size)
nuclear@0: {
nuclear@0: 	munmap(mem, size);
nuclear@0: }