This script cleans up various classes of stealth whitespace. In particular, it cleans up: - Whitespace (spaces or tabs)before newline; - DOS line endings (CR before LF); - Space before tab (spaces are deleted or converted to tabs); - Empty lines at end of file.
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| 1 | +#!/usr/bin/perl -w | |
| 2 | +# | |
| 3 | +# Clean a text file -- or directory of text files -- of stealth whitespace. | |
| 4 | +# WARNING: this can be a highly destructive operation. Use with caution. | |
| 5 | +# | |
| 6 | + | |
| 7 | +use bytes; | |
| 8 | +use File::Basename; | |
| 9 | + | |
| 10 | +# | |
| 11 | +# Clean up space-tab sequences, either by removing spaces or | |
| 12 | +# replacing them with tabs. | |
| 13 | +sub clean_space_tabs($) | |
| 14 | +{ | |
| 15 | + no bytes; # Tab alignment depends on characters | |
| 16 | + | |
| 17 | + my($li) = @_; | |
| 18 | + my($lo) = ''; | |
| 19 | + my $pos = 0; | |
| 20 | + my $nsp = 0; | |
| 21 | + my($i, $c); | |
| 22 | + | |
| 23 | + for ($i = 0; $i < length($li); $i++) { | |
| 24 | + $c = substr($li, $i, 1); | |
| 25 | + if ($c eq "\t") { | |
| 26 | + my $npos = ($pos+$nsp+8) & ~7; | |
| 27 | + my $ntab = ($npos >> 3) - ($pos >> 3); | |
| 28 | + $lo .= "\t" x $ntab; | |
| 29 | + $pos = $npos; | |
| 30 | + $nsp = 0; | |
| 31 | + } elsif ($c eq "\n" || $c eq "\r") { | |
| 32 | + $lo .= " " x $nsp; | |
| 33 | + $pos += $nsp; | |
| 34 | + $nsp = 0; | |
| 35 | + $lo .= $c; | |
| 36 | + $pos = 0; | |
| 37 | + } elsif ($c eq " ") { | |
| 38 | + $nsp++; | |
| 39 | + } else { | |
| 40 | + $lo .= " " x $nsp; | |
| 41 | + $pos += $nsp; | |
| 42 | + $nsp = 0; | |
| 43 | + $lo .= $c; | |
| 44 | + $pos++; | |
| 45 | + } | |
| 46 | + } | |
| 47 | + $lo .= " " x $nsp; | |
| 48 | + return $lo; | |
| 49 | +} | |
| 50 | + | |
| 51 | +$name = basename($0); | |
| 52 | + | |
| 53 | +foreach $f ( @ARGV ) { | |
| 54 | + print STDERR "$name: $f\n"; | |
| 55 | + | |
| 56 | + if (! -f $f) { | |
| 57 | + print STDERR "$f: not a file\n"; | |
| 58 | + next; | |
| 59 | + } | |
| 60 | + | |
| 61 | + if (!open(FILE, '+<', $f)) { | |
| 62 | + print STDERR "$name: Cannot open file: $f: $!\n"; | |
| 63 | + next; | |
| 64 | + } | |
| 65 | + | |
| 66 | + binmode FILE; | |
| 67 | + | |
| 68 | + # First, verify that it is not a binary file; consider any file | |
| 69 | + # with a zero byte to be a binary file. Is there any better, or | |
| 70 | + # additional, heuristic that should be applied? | |
| 71 | + $is_binary = 0; | |
| 72 | + | |
| 73 | + while (read(FILE, $data, 65536) > 0) { | |
| 74 | + if ($data =~ /\0/) { | |
| 75 | + $is_binary = 1; | |
| 76 | + last; | |
| 77 | + } | |
| 78 | + } | |
| 79 | + | |
| 80 | + if ($is_binary) { | |
| 81 | + print STDERR "$name: $f: binary file\n"; | |
| 82 | + next; | |
| 83 | + } | |
| 84 | + | |
| 85 | + seek(FILE, 0, 0); | |
| 86 | + | |
| 87 | + $in_bytes = 0; | |
| 88 | + $out_bytes = 0; | |
| 89 | + $blank_bytes = 0; | |
| 90 | + | |
| 91 | + @blanks = (); | |
| 92 | + @lines = (); | |
| 93 | + | |
| 94 | + while ( defined($line = <FILE>) ) { | |
| 95 | + $in_bytes += length($line); | |
| 96 | + $line =~ s/[ \t\r]*$//; # Remove trailing spaces | |
| 97 | + $line = clean_space_tabs($line); | |
| 98 | + | |
| 99 | + if ( $line eq "\n" ) { | |
| 100 | + push(@blanks, $line); | |
| 101 | + $blank_bytes += length($line); | |
| 102 | + } else { | |
| 103 | + push(@lines, @blanks); | |
| 104 | + $out_bytes += $blank_bytes; | |
| 105 | + push(@lines, $line); | |
| 106 | + $out_bytes += length($line); | |
| 107 | + @blanks = (); | |
| 108 | + $blank_bytes = 0; | |
| 109 | + } | |
| 110 | + } | |
| 111 | + | |
| 112 | + # Any blanks at the end of the file are discarded | |
| 113 | + | |
| 114 | + if ($in_bytes != $out_bytes) { | |
| 115 | + # Only write to the file if changed | |
| 116 | + seek(FILE, 0, 0); | |
| 117 | + print FILE @lines; | |
| 118 | + | |
| 119 | + if ( !defined($where = tell(FILE)) || | |
| 120 | + !truncate(FILE, $where) ) { | |
| 121 | + die "$name: Failed to truncate modified file: $f: $!\n"; | |
| 122 | + } | |
| 123 | + } | |
| 124 | + | |
| 125 | + close(FILE); | |
| 126 | +} | |