blob: cefd29e5229880ce1dfb5b6ef64be1393b34380a [file] [log] [blame]
Kyle Swenson8d8f6542021-03-15 11:02:55 -06001#!/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
7use bytes;
8use File::Basename;
9
10# Default options
11$max_width = 79;
12
13# Clean up space-tab sequences, either by removing spaces or
14# replacing them with tabs.
15sub clean_space_tabs($)
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 $lo;
51}
52
53# Compute the visual width of a string
54sub strwidth($) {
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($0);
79
80@files = ();
81
82while (defined($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
95foreach $f ( @files ) {
96 print STDERR "$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}