charset: support partial cp437 glyph replacement

diff --git a/charset.plp b/charset.plp
index e82e3d7b25f07412a26a22805f653a702bb04664..5e500047d48d8c685598a3ff7b798a65ff8d8093 100644 (file)
--- a/charset.plp
+++ b/charset.plp
@@ -297,14 +297,21 @@ sub tabinput {
                        }
                        $row{endpoint} -= $row{offset};
 
                        }
                        $row{endpoint} -= $row{offset};
 

-                       if ($row{set} eq 'cp437' and !$row{offset}) {
-                               substr($row{table}, 237, 1) = pack 'U*', 0x3D5; # phi sign
-                               substr($row{table}, 0, 32) = pack 'U*', map {hex} qw(
-                                       2007 263A 263B 2665 2666 2663 2660 2022
-                                       25D8 25CB 25D9 2642 2640 266A 266B 263C
-                                       25BA 25C4 2195 203C 00B6 00A7 25AC 21A8
-                                       2191 2193 2192 2190 221F 2194 25B2 25BC
-                               );
+                       if ($row{set} eq 'cp437') {
+                               for my $phipos (237 - $row{offset}) {
+                                       next if $phipos < 0 or $phipos > $row{endpoint};
+                                       # replace phi glyph
+                                       substr($row{table}, $phipos, 1) = pack 'U*', 0x3D5;
+                               }
+                               if ($row{offset} == 0) {
+                                       # replace control characters by visible variants
+                                       substr($row{table}, 0, 32) = pack 'U*', map {hex} qw(
+                                               2007 263A 263B 2665 2666 2663 2660 2022
+                                               25D8 25CB 25D9 2642 2640 266A 266B 263C
+                                               25BA 25C4 2195 203C 00B6 00A7 25AC 21A8
+                                               2191 2193 2192 2190 221F 2194 25B2 25BC
+                                       );
+                               }

                        }
 
                        $visible->{ascii} =  # assume common base
                        }
 
                        $visible->{ascii} =  # assume common base