Add script to format ChangeLog in the current directory.

maint/trim_changelog

@@ -0,0 +1,65 @@
+#! /usr/bin/perl -w
+
+# Try to format ChangeLog in the current directory.
+# Remove unnecessary spaces.  Add spaces when needed.
+
+use strict;
+
+my $progname = "trim_changelog";
+
+# Print message and exit (like "die", but without raising an exception).
+# System error is added at the end.
+sub error ($)
+{
+	print STDERR "$progname: ERROR: " . shift(@_) . ": $!\n";
+	exit 1;
+}
+
+if ($#ARGV != -1) {
+	print STDERR "$progname accepts no arguments\n";
+	exit 1;
+}
+
+open (CHANGELOG, "< ChangeLog") || error ("cannot open ChangeLog");
+open (CHNEW, "> ChangeLog.new") || error ("cannot open ChangeLog.new");
+
+# Convert initial spaces in ChangeLog to tabs.
+
+while (<CHANGELOG>) {
+	# Trim trailing whitespace.
+	s/\s*$//;
+
+	# Make sure there are exactly 2 spaces before the e-mail.
+	s/(^\w.*\w)\s+</$1  </;
+
+	# Make sure there are exactly 2 spaces after numeric dates.
+	if (/[0-9]+-[0-9]+-[0-9]+\w/) {
+		s/(^[0-9-]+)\s+/$1  /;
+	}
+
+	# Up to 7 spaces and tab or up to 8 spaces -> tab.
+	if (/^( {1,7}\t| {1,8})(.*)/) {
+		$_ = "\t$2";
+	}
+
+	print CHNEW "$_\n";
+}
+
+close (CHANGELOG);
+close (CHNEW);
+
+system ("cmp ChangeLog ChangeLog.new >/dev/null 2>&1");
+
+if (($? >> 8) == 0) {
+	unlink ("ChangeLog.new") || error ("Cannot remove ChangeLog.new");
+	print "$progname: ChangeLog has not been changed\n";
+	exit 0;
+}
+
+rename ("ChangeLog", "ChangeLog.bak") ||
+	error ("Cannot rename ChangeLog to ChangeLog.bak");
+
+rename ("ChangeLog.new", "ChangeLog") ||
+	error ("Cannot rename ChangeLog.new to ChangeLog");
+
+print "$progname: ChangeLog has been changed\n";