+ if (not defined $params) {
+ use List::Util qw( first pairfirst pairs );
+
+ state $INHERIT = {
+ 'cp437' => ['cp850' => 0], # ascii range overridden later
+ 'gsm0338' => ['ascii' => '0-127'],
+
+ 'iso-8859-2' => ['iso-8859-1' => '160'],
+ 'iso-8859-3' => ['iso-8859-1' => '160'],
+ 'iso-8859-4' => ['iso-8859-2' => '160'],
+ 'iso-8859-5' => ['iso-8859-1' => '160'],
+ 'iso-8859-6' => ['iso-8859-1' => '160'],
+ 'iso-8859-7' => ['iso-8859-1' => '160'],
+ 'iso-8859-8' => ['iso-8859-1' => '160'],
+ 'iso-8859-9' => ['iso-8859-1' => '208'],
+ 'iso-8859-10' => ['iso-8859-4' => '160'],
+ 'iso-8859-11' => ['iso-8859-1' => '160'],
+ 'iso-8859-13' => ['iso-8859-4' => '160'],
+ 'iso-8859-14' => ['iso-8859-1' => '160'],
+ 'iso-8859-15' => ['iso-8859-1' => '160-191'],
+ 'iso-8859-16' => ['iso-8859-2' => '160'],
+
+ 'cp1252' => ['iso-8859-1' => '128-159'],
+ 'cp1250' => ['iso-8859-2' => '128-191'],
+ 'cp1254' => ['iso-8859-9' => '128-159'],
+ 'cp1257' => ['iso-8859-13' => '128-'],
+
+ 'cp850' => ['cp437' => '144'],
+ 'cp865' => ['cp437' => '144-176'],
+ 'cp852' => ['cp850' => '128', 'cp437' => '128'],
+ 'cp857' => ['cp850' => '128-239', 'cp437' => '128'],
+ 'cp775' => ['cp850' => '128'], # partial cp437
+
+ 'MacRomanian' => ['MacRoman' => '160'],
+ 'MacCroatian' => ['MacRoman' => '160'],
+ 'MacCentralEurRoman' => ['MacRoman' => '128'],
+ 'MacTurkish' => ['MacRoman' => '208-223'], # F5 is unassigned
+ };
+
+ my @parents = @{ $INHERIT->{$input} || [] };
+
+ if (my ($parent, $part) = pairfirst { $visible->{$a} } @parents) {
+ $row{parent} = $parent;
+ $params = $part;
+ }
+ elsif ($visible->{ascii}) {
+ $row{parent} = $parents[0] || 'ascii';
+ $params = $parents[1] || 128;
+ $params = 128 if $params >= 128; # ascii offset at most
+ }
+ elsif (@parents) {
+ $row{parent} = $parents[0];
+ }
+ }
+