+# generate a regex from a shell type expression
+# see 'perl cookbook' 6.9
+sub shellregex
+{
+ my $in = shift;
+ $in =~ s{(.)} { $patmap{$1} || "\Q$1" }ge;
+ return '^' . $in . "\$";
+}
+
+# read in a file into a string and return it.
+# the filename can be split into a dir and file and the
+# file can be in upper or lower case.
+# there can also be a suffix
+sub readfilestr
+{
+ my ($dir, $file, $suffix) = @_;
+ my $fn;
+ my $f;
+ if ($suffix) {
+ $f = uc $file;
+ $fn = "$dir/$f.$suffix";
+ unless (-e $fn) {
+ $f = lc $file;
+ $fn = "$dir/$file.$suffix";
+ }
+ } elsif ($file) {
+ $f = uc $file;
+ $fn = "$dir/$file";
+ unless (-e $fn) {
+ $f = lc $file;
+ $fn = "$dir/$file";
+ }
+ } else {
+ $fn = $dir;
+ }
+
+ my $fh = new IO::File $fn;
+ my $s = undef;
+ if ($fh) {
+ local $/ = undef;
+ $s = <$fh>;
+ $fh->close;
+ }
+ return $s;
+}
+
+# write out a file in the format required for reading
+# in via readfilestr, it expects the same arguments
+# and a reference to an object
+sub writefilestr
+{
+ my $dir = shift;
+ my $file = shift;
+ my $suffix = shift;
+ my $obj = shift;
+ my $fn;
+ my $f;
+
+ confess('no object to write in writefilestr') unless $obj;
+ confess('object not a reference in writefilestr') unless ref $obj;
+
+ if ($suffix) {
+ $f = uc $file;
+ $fn = "$dir/$f.$suffix";
+ unless (-e $fn) {
+ $f = lc $file;
+ $fn = "$dir/$file.$suffix";
+ }
+ } elsif ($file) {
+ $f = uc $file;
+ $fn = "$dir/$file";
+ unless (-e $fn) {
+ $f = lc $file;
+ $fn = "$dir/$file";
+ }
+ } else {
+ $fn = $dir;
+ }
+
+ my $fh = new IO::File ">$fn";
+ if ($fh) {
+ my $dd = new Data::Dumper([ $obj ]);
+ $dd->Indent(1);
+ $dd->Terse(1);
+ $dd->Quotekeys(0);
+ # $fh->print(@_) if @_ > 0; # any header comments, lines etc
+ $fh->print($dd->Dumpxs);
+ $fh->close;
+ }
+}
+
+# remove leading and trailing spaces from an input string
+sub unpad
+{
+ my $s = shift;
+ $s =~ s/\s+$//;
+ $s =~ s/^\s+//;
+ return $s;
+}
+
+# check that a field only has callsign characters in it
+sub is_callsign
+{
+ return $_[0] =~ /^(?:[A-Z]{1,2}\d+|\d[A-Z]\d+)[A-Z0-9\/\-]+$/;
+}
+
+# check that a PC protocol field is valid text
+sub is_pctext
+{
+ return $_[0] =~ /^[\x09\x20-\xFF]+$/;
+}
+
+# check that a PC prot flag is fairly valid (doesn't check the difference between 1/0 and */-)
+sub is_pcflag
+{
+ return $_[0] =~ /^[01\*\-]+$/;
+}
+
+# check that a thing is a frequency
+sub is_freq
+{
+ return $_[0] =~ /^[\d\.]+$/;
+}
+
+# check that a thing is just digits
+sub is_digits
+{
+ return $_[0] =~ /^[\d]+$/;
+}
+
+# insert an item into a list if it isn't already there returns 1 if there 0 if not
+sub insertitem
+{
+ my $list = shift;
+ my $item = shift;
+
+ return 1 if grep {$_ eq $item } @$list;
+ push @$list, $item;
+ return 0;
+}
+
+# delete an item from a list if it is there returns no deleted
+sub deleteitem
+{
+ my $list = shift;
+ my $item = shift;
+ my $n = @$list;
+
+ @$list = grep {$_ ne $item } @$list;
+ return $n - @$list;
+}