implement Tcs; include "sys.m";	sys: Sys;include "draw.m";include "arg.m";include "bufio.m";	bufio: Bufio;	Iobuf: import bufio;include "convcs.m";	convcs: Convcs; Tcs: module{	init: fn (nil: ref Draw->Context, args: list of string);}; stderr: ref Sys->FD; init(nil: ref Draw->Context, args: list of string){	sys = load Sys Sys->PATH;	stderr = sys->fildes(2);	if ((arg := load Arg Arg->PATH) == nil)		badmodule(Arg->PATH);	if ((bufio = load Bufio Bufio->PATH) == nil)		badmodule(Bufio->PATH);	if ((convcs = load Convcs Convcs->PATH) == nil)		badmodule(Convcs->PATH); 	arg->init(args);	arg->setusage("tcs [-C configfile] [-l] [-f ics] [-t ocs] file ...");	lflag := 0;	vflag := 0;	ics := "utf8";	ocs := "utf8";	csfile := "";	while ((c := arg->opt()) != 0) {		case c {		'C' =>			csfile = arg->arg();		'f' =>			ics = arg->arg();		'l' =>			lflag = 1;		't' =>			ocs = arg->arg();		'v' =>			vflag = 1;		* =>			arg->usage();		}	}	file := arg->arg(); 	out := bufio->fopen(sys->fildes(1), Sys->OWRITE);	err := convcs->init(csfile);	if (err != nil) {		sys->fprint(stderr, "convcs: %s\n", err);		raise "fail:init";	} 	if (lflag) {		if (file != nil)			dumpaliases(out, file, vflag);		else			dumpconvs(out, vflag);		return;	}		stob: Stob;	btos: Btos;	(stob, err) = convcs->getstob(ocs);	if (err != nil) {		sys->fprint(stderr, "tcs: %s: %s\n", ocs, err);		raise "fail:badarg";	}	(btos, err) = convcs->getbtos(ics);	if (err != nil) {		sys->fprint(stderr, "tcs: %s: %s\n", ics, err);		raise "fail:badarg";	} 	fd: ref Sys->FD;	if (file == nil) {		fd = sys->fildes(0);		file = "standard input";	} else		fd = open(file); 	inbuf := array [Sys->ATOMICIO] of byte;	for(;;){		btoss: Convcs->State = nil;		stobs: Convcs->State = nil; 		unc := 0;		nc: int;		s: string;		while ((n := sys->read(fd, inbuf[unc:], len inbuf - unc)) > 0) {			n += unc;		# include unconsumed prefix			(btoss, s, nc) = btos->btos(btoss, inbuf[0:n], -1);			if (s != nil)				stobs = output(out, stob, stobs, s);			# copy down unconverted part of buffer			unc = n - nc;			if (unc > 0 && nc > 0)				inbuf[0:] = inbuf[nc: n];		}		if (n < 0) {			sys->fprint(stderr, "tcs: error reading %s: %r\n", file);			raise "fail:read error";		} 		# flush conversion state		(nil, s, nil) = btos->btos(btoss, inbuf[0: unc], 0);		if(s != nil)			stobs = output(out, stob, stobs, s);		output(out, stob, stobs, ""); 		if(out.flush() != 0) {			sys->fprint(stderr, "tcs: write error: %r\n");			raise "fail:write error";		}		file = arg->arg();		if (file == nil)			break;		fd = open(file);	}} output(out: ref Iobuf, stob: Stob, stobs: Convcs->State, s: string): Convcs->State{	outbuf: array of byte;	(stobs, outbuf) = stob->stob(stobs, s);	if(outbuf != nil)		out.write(outbuf, len outbuf);	return stobs;} badmodule(s: string){	sys->fprint(stderr, "tcs: cannot load module %s: %r\n", s);	raise "fail:init";} dumpconvs(out: ref Iobuf, verbose: int){	first := 1;	for (csl := convcs->enumcs(); csl != nil; csl = tl csl) {		(name, desc, mode) := hd csl;		if (!verbose) {			if (!first)				out.putc(' ');			out.puts(name);		} else {			ms := "";			case mode {			Convcs->BTOS =>				ms = "(from)";			Convcs->STOB =>				ms = "(to)";			}			out.puts(sys->sprint("%s%s\t%s\n", name, ms, desc));		}		first = 0;	}	if (!verbose)		out.putc('\n');	out.flush();} dumpaliases(out: ref Iobuf, cs: string, verbose: int){	(desc, asl) := convcs->aliases(cs);	if (asl == nil) {		sys->fprint(stderr, "%s\n", desc);		return;	} 	if (verbose) {		out.puts(desc);		out.putc('\n');	}	first := 1;	for (; asl != nil; asl = tl asl) {		a := hd asl;		if (!first)			out.putc(' ');		out.puts(a);		first = 0;	}	out.putc('\n');	out.flush();} open(path: string): ref Sys->FD{	fd := sys->open(path, Bufio->OREAD);	if (fd == nil) {		sys->fprint(stderr, "tcs: cannot open %s: %r\n", path);		raise "fail:open";	}	return fd;}