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 }
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