1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/src/midi.c	Thu Jan 26 00:31:39 2012 +0200
     1.3 @@ -0,0 +1,362 @@
     1.4 +#include <stdio.h>
     1.5 +#include <stdlib.h>
     1.6 +#include <string.h>
     1.7 +#include <errno.h>
     1.8 +#include <inttypes.h>
     1.9 +#include <unistd.h>
    1.10 +#include <fcntl.h>
    1.11 +#include <sys/mman.h>
    1.12 +#include <sys/stat.h>
    1.13 +#include <arpa/inet.h>
    1.14 +#include "midi.h"
    1.15 +
    1.16 +#define FMT_SINGLE		0
    1.17 +#define FMT_MULTI_TRACK	1
    1.18 +#define FMT_MULTI_SEQ	2
    1.19 +
    1.20 +/* meta events */
    1.21 +#define META_SEQ		0
    1.22 +#define META_TEXT		1
    1.23 +#define META_COPYRIGHT	2
    1.24 +#define META_NAME		3
    1.25 +#define META_INSTR		4
    1.26 +#define META_LYRICS		5
    1.27 +#define META_MARKER		6
    1.28 +#define META_CUE		7
    1.29 +#define META_CHANPREFIX	32
    1.30 +#define META_END_TRACK	47
    1.31 +#define META_TEMPO		81
    1.32 +#define META_SMPTE_OFFS	84
    1.33 +#define META_TMSIG		88
    1.34 +#define META_KEYSIG		89
    1.35 +#define META_SPECIFIC	127
    1.36 +
    1.37 +struct midi {
    1.38 +	int bpm;
    1.39 +
    1.40 +	int num_tracks;
    1.41 +	struct midi_track *tracks;
    1.42 +};
    1.43 +
    1.44 +struct midi_track {
    1.45 +	char *name;
    1.46 +	struct midi_event *head, *tail;
    1.47 +	int num_ev;
    1.48 +};
    1.49 +
    1.50 +struct midi_event {
    1.51 +	long dt;
    1.52 +	int type;
    1.53 +	int channel;
    1.54 +	int arg[2];
    1.55 +
    1.56 +	struct midi_event *next;
    1.57 +};
    1.58 +
    1.59 +#define CHUNK_HDR_SIZE	8
    1.60 +struct chunk_hdr {
    1.61 +	char id[4];
    1.62 +	uint32_t size;
    1.63 +	unsigned char data[1];
    1.64 +};
    1.65 +
    1.66 +struct midi_hdr {
    1.67 +	uint16_t fmt;	/* 0: single, 1: multi-track, 2: multiple independent */
    1.68 +	uint16_t num_tracks;
    1.69 +	uint16_t tm_div;
    1.70 +
    1.71 +} __attribute__ ((packed));
    1.72 +
    1.73 +static void destroy_track(struct midi_track *trk);
    1.74 +static int read_track(struct midi *midi, struct chunk_hdr *chunk);
    1.75 +static long read_vardata(unsigned char **pptr);
    1.76 +static int read_meta_event(struct midi *midi, struct midi_track *trk, unsigned char **pptr);
    1.77 +static int read_sysex_event(struct midi *midi, unsigned char **pptr);
    1.78 +static int ischunk(struct chunk_hdr *chunk, const char *name);
    1.79 +static struct chunk_hdr *mkchunk(void *ptr);
    1.80 +static struct chunk_hdr *skip_chunk(struct chunk_hdr *chunk);
    1.81 +static struct midi_hdr *mkmidi(void *ptr);
    1.82 +static void bigend(void *ptr, int sz);
    1.83 +static void *map_file(const char *fname, int *size);
    1.84 +static void unmap_file(void *mem, int size);
    1.85 +
    1.86 +#define IS_VALID_EVTYPE(x) ((x) >= MIDI_NOTE_OFF && (x) <= MIDI_PITCH_BEND)
    1.87 +
    1.88 +/* XXX the event arity table must match the MIDI_* defines in midi.h */
    1.89 +static int ev_arity[] = {
    1.90 +	0, 0, 0, 0, 0, 0, 0, 0,
    1.91 +	2, /* note off (note, velocity)*/
    1.92 +	2, /* note on (note, velocity)*/
    1.93 +	2, /* note aftertouch (note, aftertouch value) */
    1.94 +	2, /* controller (controller number, value) */
    1.95 +	1, /* prog change (prog number) */
    1.96 +	1, /* channel aftertouch (aftertouch value) */
    1.97 +	2  /* pitch bend (pitch LSB, pitch MSB) */
    1.98 +};
    1.99 +
   1.100 +
   1.101 +struct midi *load_midi(const char *fname)
   1.102 +{
   1.103 +	struct midi *midi;
   1.104 +	char *mem;
   1.105 +	int size;
   1.106 +	struct chunk_hdr *chunk;
   1.107 +	struct midi_hdr *hdr;
   1.108 +
   1.109 +	if(!(mem = map_file(fname, &size))) {
   1.110 +		return 0;
   1.111 +	}
   1.112 +	chunk = mkchunk(mem);
   1.113 +
   1.114 +	if(!ischunk(chunk, "MThd") || chunk->size != 6) {
   1.115 +		fprintf(stderr, "invalid or corrupted midi file: %s\n", fname);
   1.116 +		goto end;
   1.117 +	}
   1.118 +	hdr = mkmidi(chunk->data);
   1.119 +
   1.120 +	printf("format: %d\n", (int)hdr->fmt);
   1.121 +	printf("tracks: %d\n", (int)hdr->num_tracks);
   1.122 +
   1.123 +	if((hdr->tm_div & 0x8000) == 0) {
   1.124 +		/* division is in pulses / quarter note */
   1.125 +		printf("time division: %d ppqn\n", (int)hdr->tm_div);
   1.126 +	} else {
   1.127 +		/* division in frames / sec */
   1.128 +		int fps = (hdr->tm_div & 0x7f00) >> 8;
   1.129 +		int ticks_per_frame = hdr->tm_div & 0xff;
   1.130 +		printf("time division: %d fps, %d ticks/frame\n", fps, ticks_per_frame);
   1.131 +	}
   1.132 +
   1.133 +	if(!(midi = malloc(sizeof *midi))) {
   1.134 +		perror("failed to allocate memory");
   1.135 +		goto end;
   1.136 +	}
   1.137 +	if(!(midi->tracks = malloc(hdr->num_tracks * sizeof *midi->tracks))) {
   1.138 +		perror("failed to allocate memory");
   1.139 +		goto end;
   1.140 +	}
   1.141 +	midi->num_tracks = 0;
   1.142 +
   1.143 +	while((chunk = skip_chunk(chunk))) {
   1.144 +		if(ischunk(chunk, "MTrk")) {
   1.145 +			if(read_track(midi, chunk) == -1) {
   1.146 +				fprintf(stderr, "failed to read track\n");
   1.147 +			}
   1.148 +		} else {
   1.149 +			printf("ignoring chunk: %c%c%c%c\n", chunk->id[0], chunk->id[1], chunk->id[2], chunk->id[3]);
   1.150 +		}
   1.151 +	}
   1.152 +
   1.153 +end:
   1.154 +	unmap_file(mem, size);
   1.155 +	if(midi) {
   1.156 +		free_midi(midi);
   1.157 +		midi = 0;
   1.158 +	}
   1.159 +	return midi;
   1.160 +}
   1.161 +
   1.162 +void free_midi(struct midi *midi)
   1.163 +{
   1.164 +	int i;
   1.165 +
   1.166 +	if(!midi) return;
   1.167 +
   1.168 +	for(i=0; i<midi->num_tracks; i++) {
   1.169 +		destroy_track(midi->tracks + i);
   1.170 +	}
   1.171 +
   1.172 +	free(midi->tracks);	/* TODO free tracks properly */
   1.173 +	free(midi);
   1.174 +}
   1.175 +
   1.176 +static void destroy_track(struct midi_track *trk)
   1.177 +{
   1.178 +	free(trk->name);
   1.179 +	while(trk->head) {
   1.180 +		void *tmp = trk->head;
   1.181 +		trk->head = trk->head->next;
   1.182 +		free(tmp);
   1.183 +	}
   1.184 +}
   1.185 +
   1.186 +static int read_track(struct midi *midi, struct chunk_hdr *chunk)
   1.187 +{
   1.188 +	unsigned char *ptr;
   1.189 +	struct midi_track trk = {0, 0, 0, 0};
   1.190 +
   1.191 +	if(!ischunk(chunk, "MTrk")) {
   1.192 +		return -1;
   1.193 +	}
   1.194 +
   1.195 +	ptr = chunk->data;
   1.196 +	while(ptr < chunk->data + chunk->size) {
   1.197 +		long dt;
   1.198 +		unsigned char stat;
   1.199 +
   1.200 +		/* TODO also convert dt to some standard unit */
   1.201 +		dt = read_vardata(&ptr);
   1.202 +		stat = *ptr++;
   1.203 +
   1.204 +		if(stat == 0xff) {
   1.205 +			read_meta_event(midi, &trk, &ptr);
   1.206 +		} else if(stat == 0xf0) {
   1.207 +			read_sysex_event(midi, &ptr);
   1.208 +		} else {
   1.209 +			struct midi_event *ev = malloc(sizeof *ev);
   1.210 +
   1.211 +			if(trk.head) {
   1.212 +				trk.tail->next = ev;
   1.213 +			} else {
   1.214 +				trk.head = ev;
   1.215 +			}
   1.216 +			trk.tail = ev;
   1.217 +			ev->next = 0;
   1.218 +			trk.num_ev++;
   1.219 +
   1.220 +			ev->dt = dt;
   1.221 +			ev->type = (stat >> 4) & 0xf;
   1.222 +			if(!IS_VALID_EVTYPE(ev->type)) {
   1.223 +				fprintf(stderr, "warning, skipping track with unknown event %d\n", ev->type);
   1.224 +				return -1;
   1.225 +			}
   1.226 +			ev->channel = stat & 0xf;
   1.227 +
   1.228 +			ev->arg[0] = *ptr++;
   1.229 +			if(ev_arity[ev->type] > 1) {
   1.230 +				ev->arg[1] = *ptr++;
   1.231 +			}
   1.232 +		}
   1.233 +	}
   1.234 +
   1.235 +	/* if we did actually add any events ... */
   1.236 +	if(trk.num_ev) {
   1.237 +		midi->tracks[midi->num_tracks++] = trk;
   1.238 +	}
   1.239 +	return 0;
   1.240 +}
   1.241 +
   1.242 +static long read_vardata(unsigned char **pptr)
   1.243 +{
   1.244 +	int i;
   1.245 +	long res = 0;
   1.246 +	unsigned char *ptr = *pptr;
   1.247 +
   1.248 +	for(i=0; i<4; i++) {
   1.249 +		res |= (long)(*ptr & 0x7f) << (i * 8);
   1.250 +
   1.251 +		/* if first bit is not set we're done */
   1.252 +		if((*ptr++ & 0x80) == 0)
   1.253 +			break;
   1.254 +	}
   1.255 +	*pptr = ptr;
   1.256 +	return res;
   1.257 +}
   1.258 +
   1.259 +static int read_meta_event(struct midi *midi, struct midi_track *trk, unsigned char **pptr)
   1.260 +{
   1.261 +	unsigned char *ptr = *pptr;
   1.262 +	unsigned char type;
   1.263 +	long size;
   1.264 +
   1.265 +	type = *ptr++;
   1.266 +	size = read_vardata(&ptr);
   1.267 +
   1.268 +	switch(type) {
   1.269 +	case META_NAME:
   1.270 +		free(trk->name);
   1.271 +		trk->name = malloc(size + 1);
   1.272 +		memcpy(trk->name, ptr, size);
   1.273 +		trk->name[size] = 0;
   1.274 +		break;
   1.275 +
   1.276 +	case META_TEMPO:
   1.277 +		/* TODO add a tempo change event to the midi struct */
   1.278 +		break;
   1.279 +
   1.280 +	default:
   1.281 +		break;
   1.282 +	}
   1.283 +	*pptr = ptr + size;
   1.284 +	return 0;
   1.285 +}
   1.286 +
   1.287 +/* ignore sysex events */
   1.288 +static int read_sysex_event(struct midi *midi, unsigned char **pptr)
   1.289 +{
   1.290 +	long size = read_vardata(pptr);
   1.291 +	*pptr += size;
   1.292 +	return 0;
   1.293 +}
   1.294 +
   1.295 +static int ischunk(struct chunk_hdr *chunk, const char *name)
   1.296 +{
   1.297 +	return memcmp(chunk->id, name, 4) == 0;
   1.298 +}
   1.299 +
   1.300 +static struct chunk_hdr *mkchunk(void *ptr)
   1.301 +{
   1.302 +	struct chunk_hdr *chdr = ptr;
   1.303 +	bigend(&chdr->size, sizeof chdr->size);
   1.304 +	return chdr;
   1.305 +}
   1.306 +
   1.307 +static struct chunk_hdr *skip_chunk(struct chunk_hdr *chunk)
   1.308 +{
   1.309 +	return mkchunk((char*)chunk + CHUNK_HDR_SIZE + chunk->size);
   1.310 +}
   1.311 +
   1.312 +static struct midi_hdr *mkmidi(void *ptr)
   1.313 +{
   1.314 +	struct midi_hdr *midi = ptr;
   1.315 +
   1.316 +	bigend(&midi->fmt, sizeof midi->fmt);
   1.317 +	bigend(&midi->num_tracks, sizeof midi->num_tracks);
   1.318 +	bigend(&midi->tm_div, sizeof midi->tm_div);
   1.319 +	return midi;
   1.320 +}
   1.321 +
   1.322 +static void bigend(void *ptr, int sz)
   1.323 +{
   1.324 +	switch(sz) {
   1.325 +	case 4:
   1.326 +		*((uint32_t*)ptr) = ntohl(*(uint32_t*)ptr);
   1.327 +		break;
   1.328 +
   1.329 +	case 2:
   1.330 +		*(uint16_t*)ptr = ntohs(*(uint16_t*)ptr);
   1.331 +		break;
   1.332 +
   1.333 +	case 1:
   1.334 +	default:
   1.335 +		break;
   1.336 +	}
   1.337 +}
   1.338 +
   1.339 +static void *map_file(const char *fname, int *size)
   1.340 +{
   1.341 +	int fd;
   1.342 +	struct stat st;
   1.343 +	void *mem;
   1.344 +
   1.345 +	if((fd = open(fname, O_RDONLY)) == -1) {
   1.346 +		fprintf(stderr, "failed to open midi file: %s: %s\n", fname, strerror(errno));
   1.347 +		return 0;
   1.348 +	}
   1.349 +	fstat(fd, &st);
   1.350 +
   1.351 +	if((mem = mmap(0, st.st_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0)) == (void*)-1) {
   1.352 +		fprintf(stderr, "failed to map midi file: %s: %s\n", fname, strerror(errno));
   1.353 +		close(fd);
   1.354 +		return 0;
   1.355 +	}
   1.356 +	close(fd);
   1.357 +
   1.358 +	*size = st.st_size;
   1.359 +	return mem;
   1.360 +}
   1.361 +
   1.362 +static void unmap_file(void *mem, int size)
   1.363 +{
   1.364 +	munmap(mem, size);
   1.365 +}