implement Mpeg; include "sys.m";sys: Sys;FD, Connection: import Sys;include "draw.m";draw: Draw;Display, Rect, Image: import draw;include "mpeg.m"; Chroma: con 16r05; getenv(){	if(sys != nil)		return; 	sys = load Sys Sys->PATH;	draw = load Draw Draw->PATH;} copy(files: list of string, notify: chan of string, mpctl, mpdata: ref FD){	ok, n: int;	c: Connection;	name: list of string;	 	while(files != nil) {		file := hd files;		(n, name) = sys->tokenize(file, "@");		m : ref FD;		case n {		1 =>			m = sys->open(file, sys->OREAD);			if(m == nil) {				notify <-= "mpeg open:" + file;				return;			}		2 =>			(ok, c) = sys->dial(hd tl name, nil);			if(ok < 0) {				notify <-= "dial:" + hd tl name;				return;			}			sys->fprint(c.dfd, "%s\n", hd name);			c.cfd = nil;			m = c.dfd;		* =>			notify <-= "bad file:"+hd name;			return;		}		sys->stream(m, mpdata, 64*1024);		files = tl files;	}	sys->fprint(mpctl, "stop");	sys->fprint(mpctl, "window 0 0 0 0");	notify <-= "";} play(display: ref Display, w: ref Image, paint: int, r: Rect, file: string, notify: chan of string): string{ 	i, j: int;	line: string;	cfg: array of byte;	buf := array[1024] of byte;	arg, words, files: list of string; 	getenv(); 	mpdata := sys->open("/dev/mpeg", sys->OWRITE);	if(mpdata == nil)		return sys->sprint("can't open /dev/mpeg: %r"); 	obj := sys->open(file, sys->OREAD);	if(obj == nil)		return "open failed:"+file; 	n := sys->read(obj, buf, len buf);	if(n < 0)		return "mpeg object: read error"; 	mpctl := sys->open("/dev/mpegctl", sys->OWRITE);	if(mpctl == nil)		return "open mpeg ctl file"; 	# Parse into lines	(n, arg) = sys->tokenize(string buf[0:n], "\n");	for(i = 0; i < n; i++) {		# Parse into words		line = hd arg;		(j, words) = sys->tokenize(line, " \t"); 		# Pass device config lines through to the ctl file		if(hd words == "files")			files = tl words;		else {			cfg = array of byte line;			if(sys->write(mpctl, cfg, len cfg) < 0)				return "invalid device config:"+line;		}		arg = tl arg;	} 	if(files == nil)		return "no file to play"; 	# now the driver is configured initialize the dsp's	# and set up the trident overlay	sys->fprint(mpctl, "init");	sys->fprint(mpctl, "window %d %d %d %d",			r.min.x, r.min.y, r.max.x, r.max.y); 	# paint the window with the chroma key color	if(paint)		w.draw(r, keycolor(display), nil, r.min); 	if(notify != nil) {		spawn copy(files, notify, mpctl, mpdata);		return "";	}	notify = chan of string;	spawn copy(files, notify, mpctl, mpdata);	return <-notify;} ctl(msg: string): int{	mpc: ref FD; 	getenv(); 	mpc = sys->open("/dev/mpegctl", sys->OWRITE);	if(mpc == nil)		return -1; 	b := array of byte msg;	n := sys->write(mpc, b, len b);	if(n != len b)		n = -1; 	return n; } keycolor(display: ref Display): ref Image{	getenv();	return display.color(Chroma);}