comment Accessing user's files: scanfilename, inputfile, opendigit, definefont;

comment This page contains the most operating-system dependent aspects
of the TEX input system;

internal saf string array fontname[0:nfonts-1] # user name for each font code;

IFTENEX require ifc TOPS20 thenc "TEXF20.SAI" elsec "TEXFIL.SAI" endc source_file;
ENDTENEX
IFTOPS10 require "TEXF10.SAI" source_file; ENDTOPS10

ifc (SUAI or MIT) thenc

IFSUAI
saf string array fname[0:2] # file name, extension, and directory;
simp procedure scanfilename # sets up fname[0:2];
begin integer j;
fname[0]←fname[1]←fname[2]←null;
j←0;
loop	begin getnctok;
	if curcmd = spacer then done;
	if curcmd≥charcodes then
		begin backerror("Blank space should follow file name"); done;
		end;
	if curchar = "." then j←1
	else if curchar = "[" then j←2;
	fname[j]←fname[j]&curchar;
	end;
end;
ENDSUAI

IFMIT
string fnamedir, fname1, fname2;
simp procedure scanfilename # sets up file name in fnamedir, fname1, fname2;
begin
    string fcomp;           # file name component;
    boolean firstchar, vbar;
    fcomp←fnamedir←fname1←fname2←null;
    firstchar←true;
    vbar←false;
    loop    begin getnctok;
		if firstchar and curcmd = spacer then done;
		if curcmd≥charcodes then
			begin backerror("Blank space should follow file name"); done;
			end;
		if curcmd = spacer then
		    begin
			if fcomp≠null then
				if fname1=null then fname1←fcomp else fname2←fcomp;
			fcomp←null;
			if not vbar then done
		    end
		else if curchar = "|" then
			if firstchar then vbar←true else done
		else if curchar = ";" then
		    begin
			if fcomp≠null then fnamedir←fcomp;
			fcomp←null
		    end
		else fcomp←fcomp&curchar;
		firstchar←false;
	    end;
    if fcomp≠null then
	    if fname1=null then fname1←fcomp else fname2←fcomp;
    if fnamedir≠null then fnamedir←fnamedir&";";
    if fname1=null then fname1←"@";
end;
ENDMIT

internal procedure inputfile;
begin comment "\input" has just been scanned. This procedure scans the user's
file name, employing the appropriate operating system naming conventions,
then reads in the first line and feeds it to the input system;
integer chan;
label abort # if something goes wrong trying to read the file;
label try # go here to try or try again;
string flname;
integer pageno # number of pages successfully read;
define checkeof=⊂if eof then begin print(")");go to abort end⊃;
try:
scanfilename;
IFSUAI
	if fname[1]=0 then fname[1]←".TEX";
	flname←fname[0]&fname[1]&fname[2];
ENDSUAI
IFMIT
	if fname2=null then fname2←">";
	flname←fnamedir&fname1&" "&fname2;
ENDMIT
open(chan←getchan,"DSK",0,if inptr=0 then 19 else 2, 0,
	150,brchar,eof);
comment On the SAIL system, 19 buffers is the most efficient for disk files;
comment The lines read in must have at most 150 characters;
lookup(chan,flname,eof);
IFSUAI
if eof and fname[2]=0 then lookup(chan,fname[0]&fname[1]&"[TEX,SYS]",eof);
ENDSUAI
IFMIT
if eof then lookup(chan,"TEX;"&fname1&" "&fname2,eof);
ENDMIT
if eof then
	begin error("Lookup failed on file "&flname);
	release(chan); go to try;
	end;
print(" (",flname);
pushinput # save present file status;
state←newline; recovery←chan; filename←flname;
inbuf←input(chan,crffbreak) # get first line of file;
checkeof; print(" 1");
if equ(inbuf[1 to 9],"COMMENT ⊗") then
	begin comment Skip TVedit directory page;
	while brchar≠'14 and not eof do inbuf←input(chan,ffbreak);
	checkeof;
	inbuf←input(chan,crffbreak) # get first line of second page;
	checkeof; print(" 2");
	pageno←2;
	end
else pageno←1;
while brchar='14 do
	begin comment Ignore empty pages at beginning of file;
	inbuf←input(chan,crffbreak); checkeof; pageno←pageno+1; print(" ",pageno);
	end;
loc ← (pageno lsh infod) + 1 # line 1 of the current page;
if tracing land '20 then
	begin integer p # garbage bin;
	if inbuf='12 then p←lop(inbuf);
	if length(inbuf)=1 then inbuf←" "&inbuf;
	print(nextline);
	ifc MIT thenc outstr( elsec ptostr(0, endc
		inbuf[1 to ∞-1]) # show inbuf on screen;
	inbuf←inchwl&inbuf[∞ to ∞];
	end;
curbuf←inbuf;

comment Now define the output file name if it hasn't yet been defined;
IFSUAI
if ofilname=0 then declareofil(fname[0]&ofilext);
ENDSUAI
IFMIT
if ofilname=0 then declareofil(fnamedir&fname1&" "&ofilext);
ENDMIT
return;

abort: release(chan);
popinput;
end;

internal integer procedure opendigit(integer d) # Do this after "\open d =";
begin integer chan; string s;
scanfilename;
IFSUAI if fname[1]=0 then fname[1]←".TEX"; s←fname[0]&fname[1]&fname[2]; ENDSUAI
IFMIT if fname2=null then fname2←">"; s←fnamedir&fname1&" "&fname2; ENDMIT
open(chan←getchan,"DSK",0,0,2,0,0,eof);
loop	begin enter(chan,s,eof);
	if eof then
		begin print(nextline,"I can't write on file ",s,
			nextline,"Output file for \open "&d&" = ");
		s←inchwl;
		end
	else done
	end;
return(chan);
end;

internal procedure definefont(integer f) # Do this after seeing "=" of font def;
begin integer n,p,chan; string s;
label try # go here to try or try again;
try: scanfilename;
IFSUAI
    if fname[2]=0 then fname[2]←libraryarea;
    s←fname[0]&fname[2];
ENDSUAI
IFMIT
    if fnamedir=null then fnamedir←libraryarea;
    s←fnamedir&fname1&" "&fname2;
ENDMIT
    if fontname[f] and not equ(s,fontname[f]) then
	begin error("Sorry, this font code is already defined to be "&fontname[f]);
	return;
	end;
    if parbase[f]=0 then
	    begin string ss; comment font information not preloaded;
	    open(chan←getchan,"DSK",8,2,0,0,0,eof);
IFSUAI
	    lookup(chan,ss←fname[0]&deviceext&fname[2],eof);
ENDSUAI
IFMIT
	    lookup(chan,ss←fnamedir&fname1&" "&deviceext,eof);
ENDMIT
	    if eof then
		    begin error("Lookup failed on file "&ss);
		    release(chan); go to try;
		    end;
	    readfontinfo(chan,f) # input font info for use by TEXSEM and TEXOUT;
	    release(chan);
	    end;
    fontname[f]←s;
    p←fontglue+f*gluespecsize # location of "font glue";
    mem[p]←1000000 lsh infod # "infinite" reference count;
    gluespace(p)←fontpar(f,spacewd);
    gluestretch(p)←fontpar(f,spacestr);
    glueshrink(p)←fontpar(f,spaceshr);
end;
endc