cleanfile: a script to clean up stealth whitespace
This script cleans up various classes of stealth whitespace. In
particular, it cleans up:
- Whitespace (spaces or tabs)before newline;
- DOS line endings (CR before LF);
- Space before tab (spaces are deleted or converted to tabs);
- Empty lines at end of file.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
diff --git a/scripts/cleanfile b/scripts/cleanfile
new file mode 100755
index 0000000..f1ba8aa
--- /dev/null
+++ b/scripts/cleanfile
@@ -0,0 +1,126 @@
+#!/usr/bin/perl -w
+#
+# 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;
+
+#
+# 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 $lo;
+}
+
+$name = basename($0);
+
+foreach $f ( @ARGV ) {
+ print STDERR "$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;
+ $blank_bytes = 0;
+
+ @blanks = ();
+ @lines = ();
+
+ while ( defined($line = <FILE>) ) {
+ $in_bytes += length($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 = ();
+ $blank_bytes = 0;
+ }
+ }
+
+ # Any blanks at the end of the file are discarded
+
+ if ($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);
+}