-# Title: TTFMOD.PL
-# Author: M. Hosken
-# Description: Read TTF file calling user functions for each table
-# and output transformed tables to new TTF file.
-# Useage: TTFMOD provides the complete control loop for processing
-# the TTF files. All that the caller need supply is an
-# associative array of functions to call keyed by the TTF
-# table name and the two filenames.
-#
-# &ttfmod($infile, $outfile, *fns [, @must]);
-#
-# *fns is an associative array keyed by table name with
-# values of the name of the subroutine in package main to
-# be called to transfer the table from INFILE to OUTFILE.
-# The subroutine is called with the following parameters and
-# expected return values:
-#
-# ($len, $csum) = &sub(*INFILE, *OUTFILE, $len);
-#
-# INFILE and OUTFILE are the input and output streams, $len
-# is the length of the table according to the directory.
-# The return values are $len = new length of table to be
-# given in the table directory. $csum = new value of table
-# checksum. A way to test that this is correct is to
-# checksum the whole file (e.g. using CSUM.BAT) and to
-# ensure that the value is 0xB1B0AFBA according to a 32 bit
-# checksum calculated bigendien.
-#
-# @must consists of a list of tables which must exist in the
-# final output file, either by being there alread or by being
-# inserted.
-#
-# Modifications:
-# MJPH 1.00 22-SEP-1994 Original
-# MJPH 1.1 18-MAR-1998 Added @must to ttfmod()
-# MJPH 1.1.1 25-MAR-1998 Added $csum to copytab (to make reusable)
-
-package ttfmod;
-
-sub main'ttfmod {
- local($infile, $outfile, *fns, @must) = @_;
-
- # open files as binary. Notice OUTFILE is opened for update not just write
- open(INFILE, "$infile") || die "Unable top open \"$infile\" for reading";
- binmode INFILE;
- open(OUTFILE, "+>$outfile") || die "Unable to open \"$outfile\" for writing";
- binmode OUTFILE;
-
- seek(INFILE, 0, 0);
- read(INFILE, $dir_head, 12) || die "Reading table header";
- ($dir_num) = unpack("x4n", $dir_head);
- print OUTFILE $dir_head;
- # read and unpack table directory
- for ($i = 0; $i < $dir_num; $i++)
- {
- read(INFILE, $dir_val, 16) || die "Reading table entry";
- $dir{unpack("a4", $dir_val)} = join(":", $i, unpack("x4NNN", $dir_val));
- print OUTFILE $dir_val;
- printf STDERR "%s %08x\n", unpack("a4", $dir_val), unpack("x8N", $dir_val)
- if (defined $main'opt_z);
- }
- foreach $n (@must)
- {
- next if defined $dir{$n};
- $dir{$n} = "$i:0:-1:0";
- $i++; $dir_num++;
- print OUTFILE pack("a4NNN", $n, 0, -1, 0);
- }
- substr($dir_head, 4, 2) = pack("n", $dir_num);
- $csum = unpack("%32N*", $dir_head);
- $off = tell(OUTFILE);
- seek(OUTFILE, 0, 0);
- print OUTFILE $dir_head;
- seek (OUTFILE, $off, 0);
- # process tables in order they occur in the file
- @dirlist = sort byoffset keys(%dir);
- foreach $tab (@dirlist)
- {
- @tab_split = split(':', $dir{$tab});
- seek(INFILE, $tab_split[2], 0); # offset
- $tab_split[2] = tell(OUTFILE);
- if (defined $fns{$tab})
- {
- $temp = "main'$fns{$tab}";
- ($dir_len, $sum) = &$temp(*INFILE, *OUTFILE, $tab_split[3]);
- }
- else
- {
- ($dir_len, $sum) = ©tab(*INFILE, *OUTFILE, $tab_split[3]);
- }
- $tab_split[3] = $dir_len; # len
- $tab_split[1] = $sum; # checksum
- $out_dir{$tab} = join(":", @tab_split);
- }
- # now output directory in same order as original directory
- @dirlist = sort byindex keys(%out_dir);
- foreach $tab (@dirlist)
- {
- @tab_split = split(':', $out_dir{$tab});
- seek (OUTFILE, 12 + $tab_split[0] * 16, 0); # directory index
- print OUTFILE pack("A4N3", $tab, @tab_split[1..3]);
- foreach $i (1..3, 1) # checksum directory values with csum twice
- {
- $csum += $tab_split[$i];
- # this line ensures $csum stays within 32 bit bounds, clipping as necessary
- if ($csum > 0xffffffff) { $csum -= 0xffffffff; $csum--; }
- }
- # checksum the tag
- $csum += unpack("N", $tab);
- if ($csum > 0xffffffff) { $csum -= 0xffffffff; $csum--; }
- }
- # handle main checksum
- @tab_split = split(':', $out_dir{"head"});
- seek(OUTFILE, $tab_split[2], 0);
- read(OUTFILE, $head_head, 12); # read first bit of "head" table
- @head_split = unpack("N3", $head_head);
- $tab_split[1] -= $head_split[2]; # subtract old checksum
- $csum -= $head_split[2] * 2; # twice because had double effect
- # already
- if ($csum < 0 ) { $csum += 0xffffffff; $csum++; }
- $head_split[2] = 0xB1B0AFBA - $csum; # calculate new checksum
- seek (OUTFILE, 12 + $tab_split[0] * 16, 0);
- print OUTFILE pack("A4N3", "head", @tab_split[1..3]);
- seek (OUTFILE, $tab_split[2], 0); # rewrite first bit of "head" table
- print OUTFILE pack("N3", @head_split);
-
- # finish up
- close(OUTFILE);
- close(INFILE);
- }
-
-# support function for sorting by table offset
-sub byoffset {
- @t1 = split(':', $dir{$a});
- @t2 = split(':', $dir{$b});
- return 1 if ($t1[2] == -1); # put inserted tables at the end
- return -1 if ($t2[2] == -1);
- return $t1[2] <=> $t2[2];
- }
-
-# support function for sorting by directory entry order
-sub byindex {
- $t1 = split(':', $dir{$a}, 1);
- $t2 = split(':', $dir{$b}, 1);
- return $t1 <=> $t2;
- }
-
-# default table action: copies a table from input to output, recalculating
-# the checksum (just to be absolutely sure).
-sub copytab {
- local(*INFILE, *OUTFILE, $len, $csum) = @_;
-
- while ($len > 0)
- {
- $count = ($len > 8192) ? 8192 : $len; # 8K buffering
- read(INFILE, $buf, $count) == $count || die "Copying";
- $buf .= "\0" x (4 - ($count & 3)) if ($count & 3); # pad to long
- print OUTFILE $buf;
- $csum += unpack("%32N*", $buf);
- if ($csum > 0xffffffff) { $csum -= 0xffffffff; $csum--; }
- $len -= $count;
- }
- ($_[2], $csum);
- }
-
-# test routine to copy file from input to output, no changes
-package main;
-
-if ($test_package)
- {
- &ttfmod($ARGV[0], $ARGV[1], *dummy);
- }
-else
- { 1; }