$file = shift(@ARGV);
$add_gray = ".80";
$del_gray = ".60";
$program = $0;
$program =~ s/.*\///g;
sub usage {
warn "Usage: $program ORIGINAL_FILE < DIFF\n\n";
warn "Program reads a diff file from its standard input and annotates
ORIGINAL_FILE to show the changes made to the file. The easiest way to use
this program is to use it as an input filter for GNU enscript:
\$ enscript -G2re --filter='rcsdiff %s | diffpp %s' *.c *.h
\$ enscript -G2re --filter='diff %s~ %s | diffpp %s' *.c *.h
";
}
if (!defined($file) || defined($ARGV[0])) {
&usage;
exit 1;
}
if ($file eq "--help") {
&usage;
exit 0;
}
if ($file eq "--version") {
warn "diffpp 1.0\n";
exit 0;
}
open(FP, $file) || die "$program: couldn't open file `$file' for input: $!\n";
@orig_file = <FP>;
close(FP);
$[ = 1;
$orig_line_num = 1;
$orig_num_lines = @orig_file;
@diffs = <STDIN>;
$diff_line_num = 1;
$diff_num_lines = @diffs;
while ($diff_line_num <= $diff_num_lines) {
$_ = $diffs[$diff_line_num];
if (/a/) {
do_add($_);
} elsif (/d/) {
do_delete($_);
} elsif (/c/) {
do_change($_);
}
}
while ($orig_line_num <= $orig_num_lines) {
print $orig_file[$orig_line_num++];
}
sub do_add {
($line) = @_;
if ($line =~ /(\d+)a(\d+),(\d+)/) {
$insert_at_line = $1;
$num_new_lines = $3 - $2 + 1;
} elsif ($line =~ /(\d+)a(\d+)/) {
$insert_at_line = $1;
$num_new_lines = 1;
}
&skip_to_line($insert_at_line);
printf("\000shade{$add_gray}");
&mark_to_line($num_new_lines, "+");
printf("\000shade{1.0}");
}
sub do_delete {
($line) = @_;
if ($line =~ /(\d+),(\d+)d(\d+)/) {
$num_del_lines = $2 - $1 + 1;
} elsif ($line =~ /(\d+)d(\d+)/) {
$num_del_lines = 1;
}
$del_from = $1;
&skip_to_line($del_from - 1);
printf("\000shade{$del_gray}");
&mark_to_line($num_del_lines, "-");
printf("\000shade{1.0}");
$orig_line_num += $num_del_lines;
}
sub do_change {
($line) = @_;
if ($line =~ /(\d+),(\d+)c(\d+),(\d+)/) {
$num_old_lines = $2 - $1 + 1;
$num_new_lines = $4 - $3 + 1;
$change_at_line = $1;
} elsif ($line =~ /(\d+),(\d+)c(\d+)/) {
$num_old_lines = $2 - $1 + 1;
$num_new_lines = 1;
$change_at_line = $1;
} elsif ($line =~ /(\d+)c(\d+),(\d+)/) {
$num_old_lines = 1;
$num_new_lines = $3 - $2 + 1;
$change_at_line = $1;
} elsif ($line =~ /(\d+)c(\d+)/) {
$num_old_lines = 1;
$num_new_lines = 1;
$change_at_line = $1;
}
&skip_to_line($change_at_line - 1);
$orig_line_num += $num_old_lines; printf("\000shade{$del_gray}");
&mark_to_line($num_old_lines, "-");
printf("\000shade{1.0}");
printf("\000shade{$add_gray}");
&mark_to_line($num_new_lines, "+");
printf("\000shade{1.0}");
}
sub skip_to_line {
($line) = @_;
while ($orig_line_num <= $line) {
print $orig_file[$orig_line_num];
$orig_line_num++;
}
}
sub mark_to_line {
($num_lines, $marker) = @_;
$diff_line_num++; while ($num_lines > 0) {
$diff_line = substr($diffs[$diff_line_num++],3);
print "\000ps{gsave -5 0 rmoveto ($marker) show grestore}";
print $diff_line;
$num_lines--;
}
}