implement RImagefile; include "sys.m";	sys: Sys; include "draw.m"; include "bufio.m";	bufio: Bufio;	Iobuf: import bufio; include "imagefile.m"; Header: adt{	fd:	ref Iobuf;	ch:	chan of (ref Rawimage, string);	# variables in i/o routines	buf:	array of byte;	bufi:	int;	nbuf:	int; 	TYPE:	string;	CHAN:	string;	NCHAN:	string;	CMAP:	int; 	dx:	int;	dy:	int;}; NBUF:	con 8*1024; init(iomod: Bufio){	if(sys == nil)		sys = load Sys Sys->PATH;	bufio = iomod;} read(fd: ref Iobuf): (ref Rawimage, string){	# spawn a subprocess so I/O errors can clean up easily 	ch := chan of (ref Rawimage, string);	spawn readslave(fd, ch); 	return <-ch;} readmulti(fd: ref Iobuf): (array of ref Rawimage, string){	(i, err) := read(fd);	if(i != nil){		a := array[1] of { i };		return (a, err);	}	return (nil, err);} readslave(fd: ref Iobuf, ch: chan of (ref Rawimage, string)){	(header, err) := header(fd, ch);	if(header == nil){		ch <-= (nil, err);		exit;	} 	ch <-= image(header);} readerror(): string{	return sys->sprint("ReadPIC: read error: %r");} header(fd: ref Iobuf, ch: chan of (ref Rawimage, string)): (ref Header, string){	h := ref Header; 	h.fd = fd;	h.ch = ch;	h.CMAP = 0;	h.dx = 0;	h.dy = 0;	cantparse := "ReadPIC: can't parse header";	for(;;){		s := fd.gets('\n');		if(s==nil || s[len s-1]!='\n')			return (nil, cantparse);		if(s == "\n")			break;		addfield(h, s[0:len s-1]);	}	if(h.dx<=0 || h.dy<=0)		return (nil, "ReadPIC: empty picture or WINDOW not set");	return (h, nil);} addfield(h: ref Header, s: string){	baddata := "ReadPIC: not a PIC header";	for(i:=0; i<len s; i++){		if(s[i] == '=')			break;		if(s[i]==0 || s[i]>16r7f){			h.ch <-= (nil, baddata);			exit;		}	}	if(i == len s){		h.ch <-= (nil, baddata);		exit;	}	case s[0:i]{	"TYPE" =>		h.TYPE = s[i+1:];	"CHAN" =>		h.CHAN = s[i+1:];	"NCHAN" =>		h.NCHAN = s[i+1:];	"CMAP" =>		h.CMAP = 1;	"WINDOW" =>		(n, l) := sys->tokenize(s[i+1:], " ");		if(n != 4){			h.ch <-= (nil, "ReadPIC: bad WINDOW specification");			exit;		}		x0 := int hd l;		l = tl l;		y0 := int hd l;		l = tl l;		h.dx = int hd l - x0;		l = tl l;		h.dy = int hd l - y0;	}} image(h: ref Header): (ref Rawimage, string){	if(h.TYPE!="dump" || h.CHAN!="rgb" || h.NCHAN!="3" || h.CMAP)		return (nil, "ReadPIC: can't handle this type of picture"); 	i := ref Rawimage;	i.r = ((0,0), (h.dx, h.dy));	i.cmap = nil;	i.transp = 0;	i.trindex = byte 0;	i.nchans = int h.NCHAN;	i.chans = array[i.nchans] of array of byte;	for(j:=0; j<i.nchans; j++)		i.chans[j] = array[h.dx*h.dy] of byte;	i.chandesc = CRGB;	n := h.dx*h.dy;	b := array[i.nchans*n] of byte;	if(h.fd.read(b, len b) != len b)		return (nil, "ReadPIC: file too short");	l := 0;	for(j=0; j<n; j++)		for(k:=0; k<i.nchans; k++)			i.chans[k][j] = b[l++];	return (i, nil);}