Fix IS_UTF8_CHAR() to recognise start bytes 0xF5, 0xF6, 0xF7.

The refactoring of 3b0fc154d4e77cfb inadvertently introduced a bug
in Perl_is_utf8_char() and its callers, such as Perl_is_utf8_string(),
whereby the beyond-Unicode characters 0x140000 to 0x1fffff were no longer
recognised as valid.

1 files changed, 22 insertions, 2 deletions

diff --git a/lib/utf8.t b/lib/utf8.t
index 722c51de37..715ca3e7e1 100644
--- a/lib/utf8.t
+++ b/lib/utf8.t
@@ -39,8 +39,6 @@ no utf8; # Ironic, no?
 #
 #
 
-plan tests => 157;
-
 {
     # bug id 20001009.001
 
@@ -465,3 +463,25 @@ SKIP: {
    no strict 'subs';
    ok( !utf8::is_utf8( asd           ), "Wasteful format - bareword" );
 }
+
+{
+    my @highest =
+	(undef, 0x7F, 0x7FF, 0xFFFF, 0x1FFFFF, 0x3FFFFFF, 0x7FFFFFFF);
+    my @step =
+	(undef, undef, 0x40, 0x1000, 0x40000, 0x1000000, 0x40000000);
+
+    foreach my $length (6, 5, 4, 3, 2) {
+	my $high = $highest[$length];
+	while ($high > $highest[$length - 1]) {
+	    my $low = $high - $step[$length] + 1;
+	    $low = $highest[$length - 1] + 1 if $low <= $highest[$length - 1];
+	    ok(utf8::valid(do {no warnings 'utf8'; chr $low}),
+	       sprintf "chr %x, length $length is valid", $low);
+	    ok(utf8::valid(do {no warnings 'utf8'; chr $high}),
+	       sprintf "chr %x, length $length is valid", $high);
+	    $high -= $step[$length];
+	}
+    }
+}
+
+done_testing();