127 lines
2.5 KiB
Perl
Executable File
127 lines
2.5 KiB
Perl
Executable File
#!/usr/bin/perl -w
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#
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# Clean a text file -- or directory of text files -- of stealth whitespace.
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# WARNING: this can be a highly destructive operation. Use with caution.
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#
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use bytes;
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use File::Basename;
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#
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# Clean up space-tab sequences, either by removing spaces or
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# replacing them with tabs.
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sub clean_space_tabs($)
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{
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no bytes; # Tab alignment depends on characters
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my($li) = @_;
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my($lo) = '';
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my $pos = 0;
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my $nsp = 0;
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my($i, $c);
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for ($i = 0; $i < length($li); $i++) {
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$c = substr($li, $i, 1);
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if ($c eq "\t") {
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my $npos = ($pos+$nsp+8) & ~7;
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my $ntab = ($npos >> 3) - ($pos >> 3);
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$lo .= "\t" x $ntab;
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$pos = $npos;
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$nsp = 0;
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} elsif ($c eq "\n" || $c eq "\r") {
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$lo .= " " x $nsp;
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$pos += $nsp;
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$nsp = 0;
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$lo .= $c;
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$pos = 0;
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} elsif ($c eq " ") {
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$nsp++;
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} else {
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$lo .= " " x $nsp;
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$pos += $nsp;
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$nsp = 0;
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$lo .= $c;
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$pos++;
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}
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}
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$lo .= " " x $nsp;
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return $lo;
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}
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$name = basename($0);
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foreach $f ( @ARGV ) {
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print STDERR "$name: $f\n";
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if (! -f $f) {
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print STDERR "$f: not a file\n";
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next;
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}
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if (!open(FILE, '+<', $f)) {
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print STDERR "$name: Cannot open file: $f: $!\n";
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next;
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}
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binmode FILE;
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# First, verify that it is not a binary file; consider any file
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# with a zero byte to be a binary file. Is there any better, or
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# additional, heuristic that should be applied?
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$is_binary = 0;
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while (read(FILE, $data, 65536) > 0) {
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if ($data =~ /\0/) {
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$is_binary = 1;
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last;
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}
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}
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if ($is_binary) {
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print STDERR "$name: $f: binary file\n";
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next;
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}
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seek(FILE, 0, 0);
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$in_bytes = 0;
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$out_bytes = 0;
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$blank_bytes = 0;
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@blanks = ();
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@lines = ();
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while ( defined($line = <FILE>) ) {
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$in_bytes += length($line);
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$line =~ s/[ \t\r]*$//; # Remove trailing spaces
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$line = clean_space_tabs($line);
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if ( $line eq "\n" ) {
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push(@blanks, $line);
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$blank_bytes += length($line);
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} else {
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push(@lines, @blanks);
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$out_bytes += $blank_bytes;
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push(@lines, $line);
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$out_bytes += length($line);
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@blanks = ();
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$blank_bytes = 0;
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}
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}
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# Any blanks at the end of the file are discarded
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if ($in_bytes != $out_bytes) {
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# Only write to the file if changed
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seek(FILE, 0, 0);
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print FILE @lines;
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if ( !defined($where = tell(FILE)) ||
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!truncate(FILE, $where) ) {
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die "$name: Failed to truncate modified file: $f: $!\n";
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}
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}
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close(FILE);
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}
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