implement Du; include "sys.m";	sys: Sys;	sprint: import sys;include "draw.m";include "string.m";	strmod: String;include "readdir.m";	readdir: Readdir;include "bufio.m";	bufio: Bufio;	Iobuf: import bufio;include "arg.m"; aflag := 0;	# all files, not just directoriesnflag := 0;	# names only (but see -t); implies -asflag := 0;	# summary of top level namestflag := 0;	# use modification time, not size; netlib format if -n also givenuflag := 0;	# use last use (access) time, not sizeblocksize := big 1024;	# quantise length to this block size (still displayed in kb)bout: ref Iobuf; Du: module{	init:	fn(nil: ref Draw->Context, arg: list of string);}; kb(b: big): big{	return (((b + blocksize - big 1)/blocksize)*blocksize)/big 1024;} report(name: string, mtime: int, atime: int, l: big, chksum: int){	t := mtime;	if(uflag)		t = atime;	if(nflag){		if(tflag)			bout.puts(sprint("%q %ud %bd %d\n", name, t, l, chksum));		else			bout.puts(sprint("%q\n", name));	}else{		if(tflag)			bout.puts(sprint("%ud %q\n", t, name));		else			bout.puts(sprint("%-4bd %q\n", kb(l), name));	}} # Avoid loops in tangled namespaces.NCACHE: con 1024; # must be power of twocache := array[NCACHE] of list of ref sys->Dir; seen(dir: ref sys->Dir): int{	h := int dir.qid.path & (NCACHE-1);	for(c := cache[h]; c!=nil; c = tl c){		t := hd c;		if(dir.qid.path==t.qid.path && dir.dtype==t.dtype && dir.dev==t.dev)			return 1;	}	cache[h] = dir :: cache[h];	return 0;} dir(dirname: string): big{	prefix := dirname+"/";	if(dirname==".")		prefix = nil;	sum := big 0;	(de, nde) := readdir->init(dirname, readdir->NAME);	if(nde < 0)		warn("can't read", dirname);	for(i := 0; i < nde; i++) {		s := prefix+de[i].name;		if(de[i].mode & Sys->DMDIR){			if(!seen(de[i])){	# arguably should apply to files as well				size := dir(s);				sum += size;				if(!sflag && !nflag)					report(s, de[i].mtime, de[i].atime, size, 0);			}		}else{			l := de[i].length;			sum += l;			if(aflag)				report(s, de[i].mtime, de[i].atime, l, 0);		}	}	return sum;} du(name: string){	(rc, d) := sys->stat(name);	if(rc < 0){		warn("can't stat", name);		return;	}	if(d.mode & Sys->DMDIR){		d.length = dir(name);		if(nflag && !sflag)			return;	}	report(name, d.mtime, d.atime, d.length, 0);} warn(why: string, f: string){	sys->fprint(sys->fildes(2), "du: %s %q: %r\n", why, f);} init(nil: ref Draw->Context, args: list of string){	sys = load Sys Sys->PATH;	bufio = load Bufio Bufio->PATH;	strmod = load String String->PATH;	readdir = load Readdir Readdir->PATH;	arg := load Arg Arg->PATH;	if(arg == nil || bufio==nil || arg==nil || readdir==nil || readdir==nil){		sys->fprint(sys->fildes(2), "du: load Error: %r\n");		raise "fail:can't load";	}	sys->pctl(Sys->FORKFD, nil);	bout = bufio->fopen(sys->fildes(1), bufio->OWRITE);	arg->init(args);	arg->setusage("du [-anstu] [-b bsize] [file ...]");	while((o := arg->opt()) != 0)		case o {		'a' =>			aflag = 1;		'b' =>			s := arg->earg();			blocksize = big s;			if(len s > 0 && s[len s-1] == 'k')				blocksize *= big 1024;			if(blocksize <= big 0)				blocksize = big 1;		'n' =>			nflag = 1;			aflag = 1;		's' =>			sflag = 1;		't' =>			tflag = 1;		'u' =>			uflag = 1;			tflag = 1;		* =>			arg->usage();		}	args = arg->argv();	arg = nil; 	if(args==nil)		args = "." :: nil;	for(; args!=nil; args = tl args)		du(hd args);	bout.close();}