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#!/usr/bin/env perl
#
# Clean a text file -- or directory of text files -- of stealth whitespace.
# WARNING: this can be a highly destructive operation. Use with caution.
#
use bytes;
use File::Basename;
use warnings;
# Default options
$max_width = 79;
# Clean up space-tab sequences, either by removing spaces or
# replacing them with tabs.
sub clean_space_tabs($)
{
no bytes; # Tab alignment depends on characters
my($li) = @_;
my($lo) = '';
my $pos = 0;
my $nsp = 0;
my($i, $c);
for ($i = 0; $i < length($li); $i++) {
$c = substr($li, $i, 1);
if ($c eq "\t") {
my $npos = ($pos+$nsp+8) & ~7;
my $ntab = ($npos >> 3) - ($pos >> 3);
$lo .= "\t" x $ntab;
$pos = $npos;
$nsp = 0;
} elsif ($c eq "\n" || $c eq "\r") {
$lo .= " " x $nsp;
$pos += $nsp;
$nsp = 0;
$lo .= $c;
$pos = 0;
} elsif ($c eq " ") {
$nsp++;
} else {
$lo .= " " x $nsp;
$pos += $nsp;
$nsp = 0;
$lo .= $c;
$pos++;
}
}
$lo .= " " x $nsp;
return $lo;
}
# Compute the visual width of a string
sub strwidth($) {
no bytes; # Tab alignment depends on characters
my($li) = @_;
my($c, $i);
my $pos = 0;
my $mlen = 0;
for ($i = 0; $i < length($li); $i++) {
$c = substr($li,$i,1);
if ($c eq "\t") {
$pos = ($pos+8) & ~7;
} elsif ($c eq "\n") {
$mlen = $pos if ($pos > $mlen);
$pos = 0;
} else {
$pos++;
}
}
$mlen = $pos if ($pos > $mlen);
return $mlen;
}
$name = basename($0);
@files = ();
while (defined($a = shift(@ARGV))) {
if ($a =~ /^-/) {
if ($a eq '-width' || $a eq '-w') {
$max_width = shift(@ARGV)+0;
} else {
print STDERR "Usage: $name [-width #] files...\n";
exit 1;
}
} else {
push(@files, $a);
}
}
foreach $f ( @files ) {
print STDERR "$name: $f\n";
if (! -f $f) {
print STDERR "$f: not a file\n";
next;
}
if (!open(FILE, '+<', $f)) {
print STDERR "$name: Cannot open file: $f: $!\n";
next;
}
binmode FILE;
# First, verify that it is not a binary file; consider any file
# with a zero byte to be a binary file. Is there any better, or
# additional, heuristic that should be applied?
$is_binary = 0;
while (read(FILE, $data, 65536) > 0) {
if ($data =~ /\0/) {
$is_binary = 1;
last;
}
}
if ($is_binary) {
print STDERR "$name: $f: binary file\n";
next;
}
seek(FILE, 0, 0);
$in_bytes = 0;
$out_bytes = 0;
$blank_bytes = 0;
@blanks = ();
@lines = ();
$lineno = 0;
while ( defined($line = <FILE>) ) {
$lineno++;
$in_bytes += length($line);
$line =~ s/[ \t\r]*$//; # Remove trailing spaces
$line = clean_space_tabs($line);
if ( $line eq "\n" ) {
push(@blanks, $line);
$blank_bytes += length($line);
} else {
push(@lines, @blanks);
$out_bytes += $blank_bytes;
push(@lines, $line);
$out_bytes += length($line);
@blanks = ();
$blank_bytes = 0;
}
$l_width = strwidth($line);
if ($max_width && $l_width > $max_width) {
print STDERR
"$f:$lineno: line exceeds $max_width characters ($l_width)\n";
}
}
# Any blanks at the end of the file are discarded
if ($in_bytes != $out_bytes) {
# Only write to the file if changed
seek(FILE, 0, 0);
print FILE @lines;
if ( !defined($where = tell(FILE)) ||
!truncate(FILE, $where) ) {
die "$name: Failed to truncate modified file: $f: $!\n";
}
}
close(FILE);
}