#include <u.h>#include <libc.h>#include <bio.h>#define MINIMP3_IMPLEMENTATION#define MINIMP3_NO_STDIO#include "minimp3_ex.h" static int noseek;static uvlong curpos;static Biobufhdr in;static uchar inb[MINIMP3_BUF_SIZE]; static size_treadcb(void *buf, size_t size, void *){	int n;	return (n = Bread(&in, buf, size)) > 0 ? n : 0;} static intseekcb(uint64_t position, void *){	int n; 	if(noseek){		if(curpos > position)			return -1;		for(; position > 0; position -= n, curpos += n){			if((n = Bread(&in, inb, MINIMP3_MIN(position, sizeof(inb)))) < 0)				return 0;		}	}else		curpos = Bseek(&in, position, 0); 	return 0;} static voidusage(void){	fprint(2, "usage: %s [ -s SECONDS ]\n", argv0);	exits("usage");} static mp3dec_ex_t dec;static mp3dec_io_t io = {	.read = readcb,	.seek = seekcb,};static mp3d_sample_t buf[2*4410]; voidmain(int argc, char **argv){	size_t n;	double seekto;	int out, pfd[2], pid;	char fmt[32]; 	seekto = 0.0;	ARGBEGIN{	case 's':		seekto = atof(EARGF(usage()));		break;	default:		usage();	}ARGEND 	if(Binits(&in, 0, OREAD, inb, sizeof(inb)) != 0)		sysfatal("Binits");	noseek = Bseek(&in, 0, 2) < 0;	if(!noseek)		Bseek(&in, 0, 0);	if(mp3dec_ex_open_cb(&dec, &io, MP3D_SEEK_TO_SAMPLE|MP3D_DO_NOT_SCAN) != 0)		sysfatal("mp3dec_ex_open_cb");	if(seekto != 0.0)		fprint(2, "time: %g\n", (noseek || mp3dec_ex_seek(&dec, seekto*dec.info.channels*dec.info.hz) != 0) ? 0.0 : seekto); 	out = 1;	if((dec.info.channels != 2 || dec.info.hz != 44100)){		pid = -1;		if(pipe(pfd) < 0 || (pid = fork()) < 0)			sysfatal("%r");		if(pid == 0){			dup(pfd[1], 0);			close(pfd[1]);			close(pfd[0]);			snprint(fmt, sizeof(fmt), "s16c%dr%d", dec.info.channels, dec.info.hz);			execl("/bin/audio/pcmconv", "pcmconv", "-i", fmt, nil);			sysfatal("%r");		}		close(1);		close(pfd[1]);		out = pfd[0];	} 	while((n = mp3dec_ex_read(&dec, buf, nelem(buf))) > 0)		write(out, buf, n*sizeof(buf[0])); 	Bterm(&in);	close(out);	mp3dec_ex_close(&dec);	waitpid(); 	exits(nil);}