scripts/cleanfile

   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 # Default options
  11 $max_width = 79;
  12
  13 # Clean up space-tab sequences, either by removing spaces or
  14 # replacing them with tabs.
  15 sub clean_space_tabs($)
  16 {
  17     no bytes;                   # Tab alignment depends on characters
  18
  19     my($li) = @_;
  20     my($lo) = '';
  21     my $pos = 0;
  22     my $nsp = 0;
  23     my($i, $c);
  24
  25     for ($i = 0; $i < length($li); $i++) {
  26         $c = substr($li, $i, 1);
  27         if ($c eq "\t") {
  28             my $npos = ($pos+$nsp+8) & ~7;
  29             my $ntab = ($npos >> 3) - ($pos >> 3);
  30             $lo .= "\t" x $ntab;
  31             $pos = $npos;
  32             $nsp = 0;
  33         } elsif ($c eq "\n" || $c eq "\r") {
  34             $lo .= " " x $nsp;
  35             $pos += $nsp;
  36             $nsp = 0;
  37             $lo .= $c;
  38             $pos = 0;
  39         } elsif ($c eq " ") {
  40             $nsp++;
  41         } else {
  42             $lo .= " " x $nsp;
  43             $pos += $nsp;
  44             $nsp = 0;
  45             $lo .= $c;
  46             $pos++;
  47         }
  48     }
  49     $lo .= " " x $nsp;
  50     return $lo;
  51 }
  52
  53 # Compute the visual width of a string
  54 sub strwidth($) {
  55     no bytes;                   # Tab alignment depends on characters
  56
  57     my($li) = @_;
  58     my($c, $i);
  59     my $pos = 0;
  60     my $mlen = 0;
  61
  62     for ($i = 0; $i < length($li); $i++) {
  63         $c = substr($li,$i,1);
  64         if ($c eq "\t") {
  65             $pos = ($pos+8) & ~7;
  66         } elsif ($c eq "\n") {
  67             $mlen = $pos if ($pos > $mlen);
  68             $pos = 0;
  69         } else {
  70             $pos++;
  71         }
  72     }
  73
  74     $mlen = $pos if ($pos > $mlen);
  75     return $mlen;
  76 }
  77
  78 $name = basename($0);
  79
  80 @files = ();
  81
  82 while (defined($a = shift(@ARGV))) {
  83     if ($a =~ /^-/) {
  84         if ($a eq '-width' || $a eq '-w') {
  85             $max_width = shift(@ARGV)+0;
  86         } else {
  87             print STDERR "Usage: $name [-width #] files...\n";
  88             exit 1;
  89         }
  90     } else {
  91         push(@files, $a);
  92     }
  93 }
  94
  95 foreach $f ( @files ) {
  96     print STDERR "$name: $f\n";
  97
  98     if (! -f $f) {
  99         print STDERR "$f: not a file\n";
 100         next;
 101     }
 102
 103     if (!open(FILE, '+<', $f)) {
 104         print STDERR "$name: Cannot open file: $f: $!\n";
 105         next;
 106     }
 107
 108     binmode FILE;
 109
 110     # First, verify that it is not a binary file; consider any file
 111     # with a zero byte to be a binary file.  Is there any better, or
 112     # additional, heuristic that should be applied?
 113     $is_binary = 0;
 114
 115     while (read(FILE, $data, 65536) > 0) {
 116         if ($data =~ /\0/) {
 117             $is_binary = 1;
 118             last;
 119         }
 120     }
 121
 122     if ($is_binary) {
 123         print STDERR "$name: $f: binary file\n";
 124         next;
 125     }
 126
 127     seek(FILE, 0, 0);
 128
 129     $in_bytes = 0;
 130     $out_bytes = 0;
 131     $blank_bytes = 0;
 132
 133     @blanks = ();
 134     @lines  = ();
 135     $lineno = 0;
 136
 137     while ( defined($line = <FILE>) ) {
 138         $lineno++;
 139         $in_bytes += length($line);
 140         $line =~ s/[ \t\r]*$//;         # Remove trailing spaces
 141         $line = clean_space_tabs($line);
 142
 143         if ( $line eq "\n" ) {
 144             push(@blanks, $line);
 145             $blank_bytes += length($line);
 146         } else {
 147             push(@lines, @blanks);
 148             $out_bytes += $blank_bytes;
 149             push(@lines, $line);
 150             $out_bytes += length($line);
 151             @blanks = ();
 152             $blank_bytes = 0;
 153         }
 154
 155         $l_width = strwidth($line);
 156         if ($max_width && $l_width > $max_width) {
 157             print STDERR
 158                 "$f:$lineno: line exceeds $max_width characters ($l_width)\n";
 159         }
 160     }
 161
 162     # Any blanks at the end of the file are discarded
 163
 164     if ($in_bytes != $out_bytes) {
 165         # Only write to the file if changed
 166         seek(FILE, 0, 0);
 167         print FILE @lines;
 168
 169         if ( !defined($where = tell(FILE)) ||
 170              !truncate(FILE, $where) ) {
 171             die "$name: Failed to truncate modified file: $f: $!\n";
 172         }
 173     }
 174
 175     close(FILE);
 176 }