#include <stdio.h>#include <stdbool.h>#include <stdlib.h>#include <string.h>#include <fcntl.h>#include <unistd.h>#include "tags.h" #define USED(x) (void)x typedef struct Aux Aux; struct Aux {	int fd;}; static const char *t2s[] = {	[Talbum] = "album",	[Talbumartist] = "albumartist",	[Talbumgain] = "albumgain",	[Talbumpeak] = "albumpeak",	[Tartist] = "artist",	[Tcomment] = "comment",	[Tcomposer] = "composer",	[Tdate] = "date",	[Tgenre] = "genre",	[Timage] = "image",	[Ttitle] = "title",	[Ttrack] = "track",	[Ttrackgain] = "trackgain",	[Ttrackpeak] = "trackpeak",}; static bool image; static voidtag(Tagctx *ctx, int t, const char *k, const char *v, int offset, int size, Tagread f){	USED(k); USED(f);	if(image){		if(t != Timage)			return;		char *raw = malloc(size);		Aux *aux = ctx->aux;		int prevoffset = lseek(aux->fd, 0, 1);		if(lseek(aux->fd, offset, 0) != offset ||		   read(aux->fd, raw, size) != size ||		   (f != NULL && f(raw, &size) != 0)){			fprintf(stderr, "failed to read the image\n");			exit(1);		}		lseek(aux->fd, prevoffset, 0);		write(1, raw, size);		exit(0);		return;	}	if(t == Timage)		printf("%-12s %s %d %d\n", t2s[t], v, offset, size);	else if(t == Tunknown)		printf("%-12s %s\n", k, v);	else		printf("%-12s %s\n", t2s[t], v);} static voidtoc(Tagctx *ctx, int ms, int offset){	USED(ctx); USED(ms); USED(offset);} static intctxread(Tagctx *ctx, void *buf, int cnt){	Aux *aux = ctx->aux;	return read(aux->fd, buf, cnt);} static intctxseek(Tagctx *ctx, int offset, int whence){	Aux *aux = ctx->aux;	return lseek(aux->fd, offset, whence);} intmain(int argc, char **argv){	int i;	char buf[256], *argv0;	Aux aux;	Tagctx ctx = {		.read = ctxread,		.seek = ctxseek,		.tag = tag,		.toc = toc,		.buf = buf,		.bufsz = sizeof(buf),		.aux = &aux,	}; 	argv0 = argv[0];	if(argc > 1 && strcmp(argv[1], "-i") == 0){		image = true;		argc--;		argv++;	} 	if(argc < 2){		fprintf(stderr, "usage: %s [-i] FILE...\n", argv0);		return 1;	} 	for(i = 1; i < argc; i++){		if(!image)			printf("*** %s\n", argv[i]);		if((aux.fd = open(argv[i], O_RDONLY)) < 0)			perror("failed to open");		else{			if(tagsget(&ctx) != 0){				fprintf(stderr, "no tags or failed to read tags\n");				return 1;			}else if(image){				fprintf(stderr, "no images found\n");				return 1;			}else{				if(ctx.duration > 0)					printf("%-12s %d ms\n", "duration", ctx.duration);				if(ctx.samplerate > 0)					printf("%-12s %d\n", "samplerate", ctx.samplerate);				if(ctx.channels > 0)					printf("%-12s %d\n", "channels", ctx.channels);				if(ctx.bitrate > 0)					printf("%-12s %d\n", "bitrate", ctx.bitrate);			}			close(aux.fd);		}		if(i+1 < argc)			printf("\n");	} 	return 0;}