#!/usr/bin/perl
# 
# Sample mp3 player for perl.
# Requires Audio::Mad and Audio::Ao

use Audio::Mad qw(:all);
use Audio::Ao qw(:all);
use IO::Select;

my $stream   = new Audio::Mad::Stream();
my $frame    = new Audio::Mad::Frame();
my $synth    = new Audio::Mad::Synth();
my $timer    = new Audio::Mad::Timer();
my $resample = new Audio::Mad::Resample(44100, 22050);
my $dither   = new Audio::Mad::Dither();

my $select = IO::Select->new(\*STDIN);
my $BUFSIZE = 65536;

my $buffer;
my $tbytes = 0;

if (sysread(STDIN,$buffer,$BUFSIZE,0)) {
	$tbytes += length($buffer);
	print "Buffer read OK [$tbytes bytes read so far]\n";
} else {
	die("Unable to read from STDIN!?\n$!\n");
}
$stream->buffer($buffer);

initialize_ao;

my $device = open_live(default_driver_id(), 16, 22050, 2, is_big_endian(), {});
die("Unable to open sound device\n") unless defined($device);
my ($fsize);

FOO:
while (1) {
	if ($frame->decode($stream) == -1) {
		next if ($stream->err_ok());
		if ($stream->error == MAD_ERROR_BUFLEN || 
			 $stream->error == MAD_ERROR_BUFPTR) {

			# Make sure we don't drop the last frame fragment
			$buffer = substr($buffer, $stream->next_frame());

			last if (sysread(STDIN, $buffer, $BUFSIZE - length($buffer), length($buffer)) == 0);

			$tbytes += length($buffer);
			$stream->buffer($buffer);
			print "Buffer read OK [$tbytes bytes read so far]\n";

			redo FOO;
		}

		print STDERR "Fatal error\n";
		last;
	}
	$fsize = ($stream->next_frame() - $stream->this_frame()) unless defined($fsize);
	if ($fsize - 10 > ($stream->next_frame() - $stream->this_frame())) {
		$oldbuf = substr($buffer,$stream->this_frame());
	}
	$synth->synth($frame);
	my $pcm = $dither->dither($resample->resample($synth->samples()));

	play($device,$pcm,length($pcm));
}
#if (read(STDIN,$buffer,$BUFSIZE,0)) {
	#print "Buffer read OK [$tbytes bytes read so far]\n";
	#$buffer = $oldbuf . $buffer;
	#$oldbuf = undef;
	#$stream->buffer($buffer);
	#$stream->sync();
	#$tbytes += length($buffer);
	#goto FOO;
#}

close_ao($device);
shutdown_ao;