% gftodvi.ch for C compilation with web2c.
%
% History:
% 01/20/90 Karl		New gftodvi.web (same version number).
% 12/02/89 Karl Berry	To version 3.
% 
% Revision 1.7.1.5  86/02/01  15:29:58  richards
% 	Released again for MF 1.0 package
% Revision 1.7.1.4  86/02/01  15:06:50  richards
% 	Added: <nl> at end of successful run
% Revision 1.7.1.3  86/01/27  16:39:48  richards
% 	Fixed: syntax error in previous edits
% Revision 1.7.1.2  86/01/27  15:55:58  richards
% 	Added: dvi_buf_type declaration and redefined dvi_buf[] in
% 	       terms of it, so we can use it as a parameter to b_write_buf()
% Revision 1.7.1.1  86/01/27  15:39:10  richards
% 	First edit to use new binary I/O routines
% Revision 1.7  85/10/21  21:55:50  richards
% 	Released for GFtoDVI 1.7
% Revision 1.3.7.1  85/10/18  22:59:01  richards
% 	Updated for GFtoDVI Version 1.7 (Distributed w/ MF84 Version 0.9999)
% Revision 1.3.5.1  85/10/09  17:02:35  richards
% 	First draft to run at 1.5 level
% Revision 1.3  85/05/27  21:15:30  richards
% 	Updated for GFtoDVI Version 1.3 (Distributed w/ MF84 Version 0.91)
% Revision 1.2  85/04/25  19:33:30  richards
% 	Updated to GFtoDVI Version 1.2 (Distributed w/ MF84 Version 0.81)
% Revision 1.1  85/03/03  21:47:17  richards
% 	Updated for GF utilities distributed with MF Version 0.77
% Revision 1.0  84/12/16  22:38:22  richards
% 	Updated for GFtoDVI Version 1.0 (New GF file format)
% Revision 0.6  84/12/05  13:32:01  richards
% 	Updated for GFtoDVI Version 0.6; merged in changes from sdcarl!rusty
% 	Note: still has BUGFIX in section 199 to keep GFtoDVI from trying
% 	to use non-existent characters in a gray font
% Revision 0.3  84/11/17  23:51:56  richards
% 	Base version for GFtoDVI Version 0.3


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [0] WEAVE: print changes only.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
\pageno=\contentspagenumber \advance\pageno by 1
@y
\pageno=\contentspagenumber \advance\pageno by 1
\let\maybe=\iffalse
\def\title{GF$\,$\lowercase{to}$\,$DVI changes for C}
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [1] Change banner string.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
@d banner=='This is GFtoDVI, Version 3.0' {printed when the program starts}
@y
@d banner=='This is GFtoDVI, C Version 3.0' {printed when the program starts}
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [3] Redirect output to term_out.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
@d print(#)==write(#)
@d print_ln(#)==write_ln(#)
@d print_nl(#)==@+begin write_ln; write(#);@+end
@y
@d term_out==stdout
@d print(#)==write(term_out, #)
@d print_ln(#)==write_ln(term_out, #)
@d print_nl(#)==@+begin write_ln(term_out); write(term_out, #);@+end
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [still 3] Fix program header.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
@p program GF_to_DVI(@!output);
label @<Labels in the outer block@>@/
const @<Constants in the outer block@>@/
type @<Types in the outer block@>@/
var @<Globals in the outer block@>@/
procedure initialize; {this procedure gets things started properly}
  var @!i,@!j,@!m,@!n:integer; {loop indices for initializations}
  begin print_ln(banner);@/
@y
@p program GF_to_DVI;
const @<Constants in the outer block@>@/
type @<Types in the outer block@>@/
var @<Globals in the outer block@>@/
procedure initialize; {this procedure gets things started properly}
  var @!i,@!j,@!m,@!n:integer; {loop indices for initializations}
      @<Local variables for initialization@>
  begin
    if argc > n_options + arg_options + 2
    then begin
      print_ln
      ('Usage: gftodvi [-verbose] [-overflow-label-offset=<real>] <gf file>.');
@.Usage: ...@>
      uexit (1);
    end;

    @<Initialize the option variables@>;
    @<Parse arguments@>;
    if verbose then print_ln (banner);@/
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [4] Remove the final_end label.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
@x
@ If the program has to stop prematurely, it goes to the
`|final_end|'.

@d final_end=9999 {label for the end of it all}

@<Labels...@>=final_end;
@y
@ This module deleted, since it only defined the label |final_end|.
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [5] Make file_name_size match the system constant.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
@<Constants...@>=
@y
@d file_name_size==PATH_MAX {a file name shouldn't be longer than this}
@<Constants...@>=
@z
@x
@!file_name_size=50; {a file name shouldn't be longer than this}
@y
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [8] Add newline to end of abort() message, and exit abnormally.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
@d abort(#)==@+begin print(' ',#); jump_out;@+end
@y
@d abort(#)==@+begin print_ln (#); uexit (1);@+end
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [8] Remove nonlocal goto.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
@x
@p procedure jump_out;
begin goto final_end;
end;
@y
@p procedure jump_out;
begin uexit(0);
end;
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [11] The text_char type is used as an array index into xord.  The
% default type `char' produces signed integers, which are bad array
% indices in C.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
@x
@d text_char == char {the data type of characters in text files}
@y
@d text_char == ASCII_code {the data type of characters in text files}
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [14] Allow any input character.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
for i:=0 to @'37 do xchr[i]:='?';
for i:=@'177 to @'377 do xchr[i]:='?';
@y
for i:=1 to @'37 do xchr[i]:=chr(i);
for i:=@'177 to @'377 do xchr[i]:=chr(i);
@z


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [15] Change `update_terminal' to `flush', `term_in' is stdin.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
Since the terminal is being used for both input and output, some systems
need a special routine to make sure that the user can see a prompt message
before waiting for input based on that message. (Otherwise the message
may just be sitting in a hidden buffer somewhere, and the user will have
no idea what the program is waiting for.) We shall call a system-dependent
subroutine |update_terminal| in order to avoid this problem.

@d update_terminal == break(output) {empty the terminal output buffer}

@<Glob...@>=
@!buffer:array[0..terminal_line_length] of 0..255;
@!term_in:text_file; {the terminal, considered as an input file}
@y
Since the terminal is being used for both input and output, some systems
need a special routine to make sure that the user can see a prompt message
before waiting for input based on that message. (Otherwise the message
may just be sitting in a hidden buffer somewhere, and the user will have
no idea what the program is waiting for.) We shall call a system-dependent
subroutine |update_terminal| in order to avoid this problem.
@^system dependencies@>

@d update_terminal == flush (stdout) {empty the terminal output buffer}
@d term_in == stdin {standard input}

@<Glob...@>=
@!buffer:array[0..terminal_line_length] of 0..255;
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [17] Change term_in^, etc.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
@p procedure input_ln; {inputs a line from the terminal}
begin update_terminal; reset(term_in);
if eoln(term_in) then read_ln(term_in);
line_length:=0;
while (line_length<terminal_line_length)and not eoln(term_in) do
  begin buffer[line_length]:=xord[term_in^]; incr(line_length); get(term_in);
  end;
end;
@y
@p procedure input_ln; {inputs a line from the terminal}
begin update_terminal;
if eoln(term_in) then read_ln(term_in);
line_length:=0;
while (line_length<terminal_line_length)and not eoln(term_in) do
  begin buffer[line_length]:=xord[getc(term_in)]; incr(line_length);
  end;
end;
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [47] Open files based on paths.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
@p procedure open_gf_file; {prepares to read packed bytes in |gf_file|}
begin reset(gf_file,name_of_file);
cur_loc:=0;
end;
@#
procedure open_tfm_file; {prepares to read packed bytes in |tfm_file|}
begin reset(tfm_file,name_of_file);
end;
@y
In C, we use the external |test_read_access| procedure, which also does path
searching based on the user's environment or the default path.  We also
read the command line and print the banner here (since we don't want to
print the banner if the command line is unreasonable).

@p procedure open_gf_file; {prepares to read packed bytes in |gf_file|}
begin
   if test_read_access (name_of_file, GF_FILE_PATH)
   then begin
      reset (gf_file, name_of_file);
   end else begin
     print_pascal_string (name_of_file);
     abort (': GF file not found.');
   end;
   cur_loc := 0;
end;
@#
procedure open_tfm_file; {prepares to read packed bytes in |tfm_file|}
begin
   if test_read_access (name_of_file, TFM_FILE_PATH)
   then begin
      reset (tfm_file, name_of_file);
   end else begin
      print_pascal_string (name_of_file);
      abort (': TFM file not found.');
   end;
end;
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [51] Make get_n_bytes routines work with 16-bit math.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
get_two_bytes:=a*256+b;
@y
get_two_bytes:=a*toint(256)+b;
@z
@x
get_three_bytes:=(a*256+b)*256+c;
@y
get_three_bytes:=(a*toint(256)+b)*256+c;
@z
@x
if a<128 then signed_quad:=((a*256+b)*256+c)*256+d
else signed_quad:=(((a-256)*256+b)*256+c)*256+d;
@y
if a<128 then signed_quad:=((a*toint(256)+b)*256+c)*256+d
else signed_quad:=(((a-256)*toint(256)+b)*256+c)*256+d;
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [52] The memory_word structure is too hard to translate via web2c, so
% we use a hand-coded include file.  Also, b0 (et al.) is used both as a
% field and as a regular variable.  web2c puts field names in the global
% symbol table, so this loses.  Rather than fix web2c (hard), we change
% the name of the field (ugly, but easy).
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
@x
@!four_quarters = packed record@;@/
  @!b0:quarterword;
  @!b1:quarterword;
  @!b2:quarterword;
  @!b3:quarterword;
  end;
@!memory_word = record@;@/
  case boolean of
  true: (@!sc:scaled);
  false: (@!qqqq:four_quarters);
  end;
@y
@!four_quarters = packed record@;@/
  @!B0:quarterword;
  @!B1:quarterword;
  @!B2:quarterword;
  @!B3:quarterword;
  end;
@\@/@=#include "gftodmem.h";@>@\ {note the |;| so |web2c| will translate
                                  types that come after this}
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [55] fix references to .b0
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
@x
@d char_width_end(#)==#.b0].sc
@d char_width(#)==font_info[width_base[#]+char_width_end
@d char_exists(#)==(#.b0>min_quarterword)
@d char_italic_end(#)==(qo(#.b2)) div 4].sc
@d char_italic(#)==font_info[italic_base[#]+char_italic_end
@d height_depth(#)==qo(#.b1)
@d char_height_end(#)==(#) div 16].sc
@d char_height(#)==font_info[height_base[#]+char_height_end
@d char_depth_end(#)==# mod 16].sc
@d char_depth(#)==font_info[depth_base[#]+char_depth_end
@d char_tag(#)==((qo(#.b2)) mod 4)
@d skip_byte(#)==qo(#.b0)
@d next_char(#)==#.b1
@d op_byte(#)==qo(#.b2)
@d rem_byte(#)==#.b3
@y
@d char_width_end(#)==#.B0].sc
@d char_width(#)==font_info[width_base[#]+char_width_end
@d char_exists(#)==(#.B0>min_quarterword)
@d char_italic_end(#)==(qo(#.B2)) div 4].sc
@d char_italic(#)==font_info[italic_base[#]+char_italic_end
@d height_depth(#)==qo(#.B1)
@d char_height_end(#)==(#) div 16].sc
@d char_height(#)==font_info[height_base[#]+char_height_end
@d char_depth_end(#)==# mod 16].sc
@d char_depth(#)==font_info[depth_base[#]+char_depth_end
@d char_tag(#)==((qo(#.B2)) mod 4)
@d skip_byte(#)==qo(#.B0)
@d next_char(#)==#.B1
@d op_byte(#)==qo(#.B2)
@d rem_byte(#)==#.B3
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [60] Fix 16-bit arithmetic bugs in TFM calculations.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
@x
@ @d read_two_halves_end(#)==#:=b2*256+b3
@d read_two_halves(#)==read_tfm_word; #:=b0*256+b1; read_two_halves_end
@y
@ @d read_two_halves_end(#)==#:=b2*toint(256)+b3
@d read_two_halves(#)==read_tfm_word; #:=b0*toint(256)+b1; read_two_halves_end
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [62] More .b?'s.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
@x
  qw.b0:=qi(b0); qw.b1:=qi(b1); qw.b2:=qi(b2); qw.b3:=qi(b3);
@y
  qw.B0:=qi(b0); qw.B1:=qi(b1); qw.B2:=qi(b2); qw.B3:=qi(b3);
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [62] More arithmetic fixes.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
@x
z:=((b0*256+b1)*256+b2)*16+(b3 div 16);
@y
z:=((b0*toint(256)+b1)*toint(256)+b2)*16+(b3 div 16);
@z
@x
      else if 256*(b2-128)+b3>=nk then abend;
@y
      else if toint(256)*(b2-128)+b3>=nk then abend;
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [78] Change default extension to `.2602gf'.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
l:=3; init_str3(".")("g")("f")(gf_ext);@/
@y
l:=7; init_str7(".")("2")("6")("0")("2")("g")("f")(gf_ext);@/
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [88] Change home_font_area to null_string.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
@ Font metric files whose areas are not given
explicitly are assumed to appear in a standard system area called
|home_font_area|.  This system area name will, of course, vary from place
to place. The program here sets it to `\.{TeXfonts:}'.
@^system dependencies@>
@.TeXfonts@>

@<Initialize the strings@>=
l:=9; init_str9("T")("e")("X")("f")("o")("n")("t")("s")(":")(home_font_area);@/
@y
@ Font metric files whose areas are not given
explicitly are assumed to appear in a standard system area called
|home_font_area|.  This system area name will, of course, vary from place
to place. In the {\mc UNIX} version, we set |home_font_area|
to |null_string| because the default areas to search for \.{TFM} files
are built into the routine |test_read_access|.
@^system dependencies@>

@<Initialize the strings@>=
l:=0; init_str0(home_font_area);@/
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [90] Change more_name to understand UNIX file name syntax.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
else  begin if (c=">")or(c=":") then
    begin area_delimiter:=pool_ptr; ext_delimiter:=0;
    end
  else if (c=".")and(ext_delimiter=0) then ext_delimiter:=pool_ptr;
@y
else  begin if (c="/") then
    begin area_delimiter:=pool_ptr; ext_delimiter:=0;
    end
  else if c="." then ext_delimiter:=pool_ptr;
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [94] Change start_gf to get file name from the command line.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
@ The |start_gf| procedure prompts the user for the name of the generic
font file to be input. It opens the file, making sure that some input is
present; then it opens the output file.

Although this routine is system-independent, it should probably be
modified to take the file name from the command line (without an initial
prompt), on systems that permit such things.

@p procedure start_gf;
label found,done;
begin loop@+begin print_nl('GF file name: '); input_ln;
@.GF file name@>
  buf_ptr:=0; buffer[line_length]:="?";
  while buffer[buf_ptr]=" " do incr(buf_ptr);
  if buf_ptr<line_length then
    begin @<Scan the file name in the buffer@>;
    if cur_ext=null_string then cur_ext:=gf_ext;
    pack_file_name(cur_name,cur_area,cur_ext); open_gf_file;
    if not eof(gf_file) then goto found;
    print_nl('Oops... I can''t find file '); print(name_of_file);
@.Oops...@>
@.I can't find...@>
    end;
  end;
found:job_name:=cur_name; pack_file_name(job_name,null_string,dvi_ext);
open_dvi_file;
end;
@y
@ The |start_gf| procedure obtains the name of the generic font file to
be input from the command line.  It opens the file, making sure that
some input is present; then it opens the output file.

@p procedure start_gf;
label done;
var arg_buffer: packed array [1..PATH_MAX] of char;
    arg_buf_ptr: 1..PATH_MAX;
begin
  if optind = argc
  then begin
    print ('GF file name: ');
    input_ln;
@.GF file name:@>
  end else begin
    argv (optind, arg_buffer);
    arg_buffer[PATH_MAX] := ' ';
    arg_buf_ptr := 1;
    line_length := 0;
    while (arg_buf_ptr < PATH_MAX)
          and (arg_buffer[arg_buf_ptr] = ' ')
      do incr(arg_buf_ptr);

    while (arg_buf_ptr < PATH_MAX)
          and (line_length < terminal_line_length)
          and (arg_buffer[arg_buf_ptr] <> ' ')
    do begin
      buffer[line_length] := xord[arg_buffer[arg_buf_ptr]];
      incr(line_length);
      incr(arg_buf_ptr);
    end;
  end;

  buf_ptr:=0; buffer[line_length]:="?";
  while buffer[buf_ptr]=" " do incr(buf_ptr);
  if buf_ptr < line_length
  then begin
    @<Scan the file name in the buffer@>;
    if cur_ext = null_string then cur_ext:=gf_ext;
    pack_file_name (cur_name, cur_area, cur_ext);
    open_gf_file;
  end;
  job_name := cur_name;
  pack_file_name(job_name, null_string, dvi_ext);
  open_dvi_file;
end;
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [107] `write_dvi' is now an external C routine.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
@p procedure write_dvi(@!a,@!b:dvi_index);
var k:dvi_index;
begin for k:=a to b do write(dvi_file,dvi_buf[k]);
end;
@y
In C, we can write out the entire array with one call.
@p procedure write_dvi(@!a,@!b:dvi_index);
begin 
  write_chunk (dvi_file, dvi_buf, a, b);
end;
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [111] More .b?'s.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
@x
dvi_out(qo(font_check[f].b0));
dvi_out(qo(font_check[f].b1));
dvi_out(qo(font_check[f].b2));
dvi_out(qo(font_check[f].b3));@/
@y
dvi_out(qo(font_check[f].B0));
dvi_out(qo(font_check[f].B1));
dvi_out(qo(font_check[f].B2));
dvi_out(qo(font_check[f].B3));@/
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [115] Don't go to final_end, just exit; this is the normal exit from
% the program, so we want to end with a newline if we are being verbose.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
goto final_end;
@y
if verbose then print_ln (' ');
uexit (0);
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [118] And still more .b?'s.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
@x
dummy_info.b0:=qi(0); dummy_info.b1:=qi(0); dummy_info.b2:=qi(0);
dummy_info.b3:=qi(0);
@y
dummy_info.B0:=qi(0); dummy_info.B1:=qi(0); dummy_info.B2:=qi(0);
dummy_info.B3:=qi(0);
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [138] write_ln formatting.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
@x
  begin print_nl('Sorry, I can''t make diagonal rules of slant ',r:10:5,'!');
@y
  begin print_nl('Sorry, I can''t make diagonal rules of slant ');
        print_real(r,10,5); print('!');
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [164] No progress report unless verbose.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
@x
print('[',total_pages:1); update_terminal; {print a progress report}
@y
if verbose
then begin
  print('[',total_pages:1);
  update_terminal; {print a progress report}
end;
@z

@x
print(']'); update_terminal;
@y
if verbose
then begin
  print(']');
  if total_pages mod 13 = 0
  then print_ln (' ')
  else print (' ');
  update_terminal;
end;
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [170] Change offset for overflow labels.  The defaults adds about 2.1
% inches to the right edge of the diagram, which puts it off the paper
% for even moderately large fonts.  Instead, we make it a command-line
% option.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
over_col:=over_col+delta_x+10000000;
@y
over_col := over_col + delta_x + overflow_label_offset;
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [215] Some broken compilers cannot handle 165 labels for the same
% branch of a switch.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
@<Read and process...@>=
loop  @+begin continue: case cur_gf of
  sixty_four_cases(0): k:=cur_gf;
  paint1:k:=get_byte;
  paint2:k:=get_two_bytes;
  paint3:k:=get_three_bytes;
  eoc:goto done1;
  skip0:end_with(blank_rows:=0; do_skip);
  skip1:end_with(blank_rows:=get_byte; do_skip);
  skip2:end_with(blank_rows:=get_two_bytes; do_skip);
  skip3:end_with(blank_rows:=get_three_bytes; do_skip);
  sixty_four_cases(new_row_0),sixty_four_cases(new_row_0+64),
   thirty_two_cases(new_row_0+128),five_cases(new_row_0+160):
    end_with(z:=cur_gf-new_row_0;paint_black:=true);
  xxx1,xxx2,xxx3,xxx4,yyy,no_op:begin skip_nop; goto continue;
    end;
  othercases bad_gf('Improper opcode')
  endcases;@/
@y
@<Read and process...@>=
loop  @+begin continue:
 if (cur_gf>=new_row_0)and(cur_gf<=new_row_0+164) then
    end_with(z:=cur_gf-new_row_0;paint_black:=true)
 else case cur_gf of
  sixty_four_cases(0): k:=cur_gf;
  paint1:k:=get_byte;
  paint2:k:=get_two_bytes;
  paint3:k:=get_three_bytes;
  eoc:goto done1;
  skip0:end_with(blank_rows:=0; do_skip);
  skip1:end_with(blank_rows:=get_byte; do_skip);
  skip2:end_with(blank_rows:=get_two_bytes; do_skip);
  skip3:end_with(blank_rows:=get_three_bytes; do_skip);
  xxx1,xxx2,xxx3,xxx4,yyy,no_op:begin skip_nop; goto continue;
    end;
  othercases bad_gf('Improper opcode')
  endcases;@/
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [219] Call `setpaths'.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
start_gf; {open the input and output files}
@y
{initialize paths from environment variables}
set_paths (GF_FILE_PATH_BIT + TFM_FILE_PATH_BIT);
start_gf; {open the input and output files}
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [still 219] If verbose, output a newline at the end.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
final_end:end.
@y
  if verbose and (total_pages mod 13 <> 0) then print_ln (' ');
end.
@z

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% [222] System-dependent changes.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
@x
@* System-dependent changes.
This section should be replaced, if necessary, by changes to the program
that are necessary to make \.{GFtoDVI} work at a particular installation.
It is usually best to design your change file so that all changes to
previous sections preserve the section numbering; then everybody's version
will be consistent with the printed program. More extensive changes,
which introduce new sections, can be inserted here; then only the index
itself will get a new section number.
@^system dependencies@>
@y
@* System-dependent changes.  We want to parse a Unix-style command
line.

This macro tests if its argument is the current option, as represented
by the index variable |option_index|.

@d argument_is (#) == (strcmp (long_options[option_index].name, #) = 0)

@<Parse arguments@> =
begin
  @<Define the option table@>;
  repeat
    getopt_return_val := getopt_long_only (argc, gargv, '', long_options,
                                           address_of_int (option_index));
    if getopt_return_val <> -1
    then begin
      if getopt_return_val = "?"
      then uexit (1); {|getopt| has already given an error message.}
      
      if argument_is ('overflow-label-offset')
      then begin
        offset_in_points := atof (optarg);
        overflow_label_offset := round (offset_in_points * 65536);
      end
      
      else
        {It was just a flag; |getopt| has already done the assignment.}
        do_nothing;
    end;
  until getopt_return_val = -1;

  {Now |optind| is the index of first non-option on the command line.}
end


@ The array of information we pass in.  The type |getopt_struct| is
defined in C, to avoid type clashes.  We also need to know the return
value from getopt, and the index of the current option.

@<Local var...@> =
@!long_options: array[0..n_options] of getopt_struct;
@!getopt_return_val: integer;
@!option_index: integer;
@!current_option: 0..n_options;

@ Here are the options we allow.  The first is just a switch that
determines whether or not we print status information.
@.-verbose@>

@<Define the option...@> =
current_option := 0;
long_options[0].name := 'verbose';
long_options[0].has_arg := 0;
long_options[0].flag := address_of_int (verbose);
long_options[0].val := 1;
incr (current_option);

@ Here is the variable to go with the switch.

@<Glob...@> =
@!verbose: integer;

@ |verbose| starts off |false|.

@<Initialize the option...@> =
verbose := false;

@ The second option determines how far from the right edge of the
character boxes we print overflow labels.
@.-overflow-label-offset@>

@<Define the option...@> =
long_options[current_option].name := 'overflow-label-offset';
long_options[current_option].has_arg := 1;
long_options[current_option].flag := 0;
long_options[current_option].val := 0;
incr (current_option);

@ It's easier on the user to specify the value in \TeX\ points, but we
want to store it in scaled points.

@<Glob...@> =
@!overflow_label_offset: integer; {in scaled points}
@!offset_in_points: real;

@ The default offset is ten million scaled points---a little more than
two inches.

@<Initialize the option...@> =
overflow_label_offset := 10000000;

@ An element with all zeros always ends the list.

@<Define the option...@> =
long_options[current_option].name := 0;
long_options[current_option].has_arg := 0;
long_options[current_option].flag := 0;
long_options[current_option].val := 0;

@ Pascal compilers won't count the number of elements in an array
constant for us.  This doesn't include the zero-element at the end,
because this array starts at index zero.

@<Constants...@> =
n_options = 2;
arg_options = 1;
@z