Re-factor heuristics to recognize unknown glyphs for |toUnicode|

src/core/fonts.js

@@ -4310,26 +4310,30 @@ var Font = (function FontClosure() {
           var glyphName = encoding[charcode];
           // b) Look up the character name in the Adobe Glyph List (see the
           //    Bibliography) to obtain the corresponding Unicode value.
-          if (glyphName === '' || !(glyphName in GlyphsUnicode)) {
+          if (glyphName === '') {
+            continue;
+          } else if (GlyphsUnicode[glyphName] === undefined) {
             // (undocumented) c) Few heuristics to recognize unknown glyphs
             // NOTE: Adobe Reader does not do this step, but OSX Preview does
-            var code;
+            var code = 0;
-            // Gxx glyph
+            switch (glyphName[0]) {
-            if (glyphName.length === 3 &&
+              case 'G': // Gxx glyph
-                glyphName[0] === 'G' &&
+                if (glyphName.length === 3) {
-                (code = parseInt(glyphName.substr(1), 16))) {
+                  code = parseInt(glyphName.substr(1), 16);
-              toUnicode[charcode] = String.fromCharCode(code);
                 }
-            // g00xx glyph
+                break;
-            if (glyphName.length === 5 &&
+              case 'g': // g00xx glyph
-                glyphName[0] === 'g' &&
+                if (glyphName.length === 5) {
-                (code = parseInt(glyphName.substr(1), 16))) {
+                  code = parseInt(glyphName.substr(1), 16);
-              toUnicode[charcode] = String.fromCharCode(code);
+                }
+                break;
+              case 'C': // Cddd glyph
+                if (glyphName.length >= 3) {
+                  code = +glyphName.substr(1);
+                }
+                break;
             }
-            // Cddd glyph
+            if (code) {
-            if (glyphName.length >= 3 &&
-                glyphName[0] === 'C' &&
-                (code = +glyphName.substr(1))) {
               toUnicode[charcode] = String.fromCharCode(code);
             }
             continue;