scripts/cleanfile

   1 #!/usr/bin/env perl
   2 # SPDX-License-Identifier: GPL-2.0
   3 #
   4 # Clean a text file -- or directory of text files -- of stealth whitespace.
   5 # WARNING: this can be a highly destructive operation.  Use with caution.
   6 #
   7
   8 use warnings;
   9 use bytes;
  10 use File::Basename;
  11
  12 # Default options
  13 $max_width = 79;
  14
  15 # Clean up space-tab sequences, either by removing spaces or
  16 # replacing them with tabs.
  17 sub clean_space_tabs($)
  18 {
  19     no bytes;                   # Tab alignment depends on characters
  20
  21     my($li) = @_;
  22     my($lo) = '';
  23     my $pos = 0;
  24     my $nsp = 0;
  25     my($i, $c);
  26
  27     for ($i = 0; $i < length($li); $i++) {
  28         $c = substr($li, $i, 1);
  29         if ($c eq "\t") {
  30             my $npos = ($pos+$nsp+8) & ~7;
  31             my $ntab = ($npos >> 3) - ($pos >> 3);
  32             $lo .= "\t" x $ntab;
  33             $pos = $npos;
  34             $nsp = 0;
  35         } elsif ($c eq "\n" || $c eq "\r") {
  36             $lo .= " " x $nsp;
  37             $pos += $nsp;
  38             $nsp = 0;
  39             $lo .= $c;
  40             $pos = 0;
  41         } elsif ($c eq " ") {
  42             $nsp++;
  43         } else {
  44             $lo .= " " x $nsp;
  45             $pos += $nsp;
  46             $nsp = 0;
  47             $lo .= $c;
  48             $pos++;
  49         }
  50     }
  51     $lo .= " " x $nsp;
  52     return $lo;
  53 }
  54
  55 # Compute the visual width of a string
  56 sub strwidth($) {
  57     no bytes;                   # Tab alignment depends on characters
  58
  59     my($li) = @_;
  60     my($c, $i);
  61     my $pos = 0;
  62     my $mlen = 0;
  63
  64     for ($i = 0; $i < length($li); $i++) {
  65         $c = substr($li,$i,1);
  66         if ($c eq "\t") {
  67             $pos = ($pos+8) & ~7;
  68         } elsif ($c eq "\n") {
  69             $mlen = $pos if ($pos > $mlen);
  70             $pos = 0;
  71         } else {
  72             $pos++;
  73         }
  74     }
  75
  76     $mlen = $pos if ($pos > $mlen);
  77     return $mlen;
  78 }
  79
  80 $name = basename($0);
  81
  82 @files = ();
  83
  84 while (defined($a = shift(@ARGV))) {
  85     if ($a =~ /^-/) {
  86         if ($a eq '-width' || $a eq '-w') {
  87             $max_width = shift(@ARGV)+0;
  88         } else {
  89             print STDERR "Usage: $name [-width #] files...\n";
  90             exit 1;
  91         }
  92     } else {
  93         push(@files, $a);
  94     }
  95 }
  96
  97 foreach $f ( @files ) {
  98     print STDERR "$name: $f\n";
  99
 100     if (! -f $f) {
 101         print STDERR "$f: not a file\n";
 102         next;
 103     }
 104
 105     if (!open(FILE, '+<', $f)) {
 106         print STDERR "$name: Cannot open file: $f: $!\n";
 107         next;
 108     }
 109
 110     binmode FILE;
 111
 112     # First, verify that it is not a binary file; consider any file
 113     # with a zero byte to be a binary file.  Is there any better, or
 114     # additional, heuristic that should be applied?
 115     $is_binary = 0;
 116
 117     while (read(FILE, $data, 65536) > 0) {
 118         if ($data =~ /\0/) {
 119             $is_binary = 1;
 120             last;
 121         }
 122     }
 123
 124     if ($is_binary) {
 125         print STDERR "$name: $f: binary file\n";
 126         next;
 127     }
 128
 129     seek(FILE, 0, 0);
 130
 131     $in_bytes = 0;
 132     $out_bytes = 0;
 133     $blank_bytes = 0;
 134
 135     @blanks = ();
 136     @lines  = ();
 137     $lineno = 0;
 138
 139     while ( defined($line = <FILE>) ) {
 140         $lineno++;
 141         $in_bytes += length($line);
 142         $line =~ s/[ \t\r]*$//;         # Remove trailing spaces
 143         $line = clean_space_tabs($line);
 144
 145         if ( $line eq "\n" ) {
 146             push(@blanks, $line);
 147             $blank_bytes += length($line);
 148         } else {
 149             push(@lines, @blanks);
 150             $out_bytes += $blank_bytes;
 151             push(@lines, $line);
 152             $out_bytes += length($line);
 153             @blanks = ();
 154             $blank_bytes = 0;
 155         }
 156
 157         $l_width = strwidth($line);
 158         if ($max_width && $l_width > $max_width) {
 159             print STDERR
 160                 "$f:$lineno: line exceeds $max_width characters ($l_width)\n";
 161         }
 162     }
 163
 164     # Any blanks at the end of the file are discarded
 165
 166     if ($in_bytes != $out_bytes) {
 167         # Only write to the file if changed
 168         seek(FILE, 0, 0);
 169         print FILE @lines;
 170
 171         if ( !defined($where = tell(FILE)) ||
 172              !truncate(FILE, $where) ) {
 173             die "$name: Failed to truncate modified file: $f: $!\n";
 174         }
 175     }
 176
 177     close(FILE);
 178 }