6623219: Font.canDisplayUpTo does not work with supplementary characters

Reviewed-by: prr, peytoia

src/share/classes/java/awt/Font.java

@@ -1985,8 +1985,22 @@ public class Font implements java.io.Serializable
      * @since 1.2
      */
     public int canDisplayUpTo(String str) {
-        return canDisplayUpTo(new StringCharacterIterator(str), 0,
-            str.length());
+        Font2D font2d = getFont2D();
+        int len = str.length();
+        for (int i = 0; i < len; i++) {
+            char c = str.charAt(i);
+            if (font2d.canDisplay(c)) {
+                continue;
+            }
+            if (!Character.isHighSurrogate(c)) {
+                return i;
+            }
+            if (!font2d.canDisplay(str.codePointAt(i))) {
+                return i;
+            }
+            i++;
+        }
+        return -1;
     }
 
     /**
@@ -2009,11 +2023,21 @@ public class Font implements java.io.Serializable
      * @since 1.2
      */
     public int canDisplayUpTo(char[] text, int start, int limit) {
-        while (start < limit && canDisplay(text[start])) {
-            ++start;
+        Font2D font2d = getFont2D();
+        for (int i = start; i < limit; i++) {
+            char c = text[i];
+            if (font2d.canDisplay(c)) {
+                continue;
+            }
+            if (!Character.isHighSurrogate(c)) {
+                return i;
+            }
+            if (!font2d.canDisplay(Character.codePointAt(text, i, limit))) {
+                return i;
+            }
+            i++;
         }
-
-        return start == limit ? -1 : start;
+        return -1;
     }
 
     /**
@@ -2034,13 +2058,26 @@ public class Font implements java.io.Serializable
      * @since 1.2
      */
     public int canDisplayUpTo(CharacterIterator iter, int start, int limit) {
-        for (char c = iter.setIndex(start);
-             iter.getIndex() < limit && canDisplay(c);
-             c = iter.next()) {
+        Font2D font2d = getFont2D();
+        char c = iter.setIndex(start);
+        for (int i = start; i < limit; i++, c = iter.next()) {
+            if (font2d.canDisplay(c)) {
+                continue;
+            }
+            if (!Character.isHighSurrogate(c)) {
+                return i;
+            }
+            char c2 = iter.next();
+            // c2 could be CharacterIterator.DONE which is not a low surrogate.
+            if (!Character.isLowSurrogate(c2)) {
+                return i;
+            }
+            if (!font2d.canDisplay(Character.toCodePoint(c, c2))) {
+                return i;
+            }
+            i++;
         }
-
-        int result = iter.getIndex();
-        return result == limit ? -1 : result;
+        return -1;
     }
 
     /**

test/java/awt/FontClass/SurrogateTest/SupplementaryCanDisplayUpToTest.java

+/*
+ * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 6623219
+ * @summary Test canDisplayUpTo with supplementary characters.
+ */
+
+import java.awt.*;
+import java.text.*;
+
+public class SupplementaryCanDisplayUpToTest {
+    // Lists consisting of a font name, test text, and its expected
+    // return value. Test text uses private area code point U+F0000
+    // (\udb80\udc00).
+    private static String[][] DATA = {
+        // Windows
+        { "Meiryo", "\ud87e\udd45\ud87e\udd47\udb80\udc00", "4" },
+        { "Meiryo", "\ud87e\udd45\ud87e\udd47\udb80Z", "4" },
+        { "Meiryo", "\ud87e\udd45\ud87e\udd47\udb80", "4" },
+        { "Meiryo", "\ud87e\udd45\ud87e\udd47\udc00", "4" },
+        { "Meiryo", "\ud87e\udd45\ud87e\udd47", "-1" },
+
+        // Linux
+        { "AR PL UMing TW", "\ud87e\udc25\ud87e\udc3b\udb80\udc00", "4" },
+        { "AR PL UMing TW", "\ud87e\udc25\ud87e\udc3b\udb80Z", "4" },
+        { "AR PL UMing TW", "\ud87e\udc25\ud87e\udc3b\udb80", "4" },
+        { "AR PL UMing TW", "\ud87e\udc25\ud87e\udc3b\udc00", "4" },
+        { "AR PL UMing TW", "\ud87e\udc25\ud87e\udc3b", "-1" },
+
+        // Solaris
+        { "FZMingTi", "\ud87e\udc25\ud87e\udc3b\udb80\udc00", "4" },
+        { "FZMingTi", "\ud87e\udc25\ud87e\udc3b\udb80Z", "4" },
+        { "FZMingTi", "\ud87e\udc25\ud87e\udc3b\udb80", "4" },
+        { "FZMingTi", "\ud87e\udc25\ud87e\udc3b\udc00", "4" },
+        { "FZMingTi", "\ud87e\udc25\ud87e\udc3b", "-1" },
+    };
+    private static int errorcount = 0;
+
+    public static void main(String[] args) {
+        for (String[] data : DATA) {
+            String fontname = data[0];
+            Font font = new Font(fontname, Font.PLAIN, 16);
+            if (font.getFamily().equals(Font.DIALOG)) {
+                // Skip any unavailable fonts.
+                continue;
+            }
+
+            System.out.printf("Testing with font '%s'... ", fontname);
+            int errors = 0;
+            String text = data[1];
+            int expected = Integer.parseInt(data[2]);
+
+            int result = font.canDisplayUpTo(text);
+            if (result != expected) {
+                System.err.println("canDisplayUpTo(String) returns " + result);
+                errors++;
+            }
+
+            result = font.canDisplayUpTo(text.toCharArray(), 0, text.length());
+            if (result != expected) {
+                System.err.println("canDisplayUpTo(char[], int, int) returns " + result);
+                errors++;
+            }
+
+            CharacterIterator iter = new StringCharacterIterator(text);
+            result = font.canDisplayUpTo(iter, iter.getBeginIndex(), iter.getEndIndex());
+            if (result != expected) {
+                System.err.println("canDisplayUpTo(CharacterIterator, int, int) returns " + result);
+                errors++;
+            }
+
+            if (errors == 0) {
+                System.out.println("passed");
+            } else {
+                System.out.println("failed");
+                errorcount += errors;
+            }
+        }
+        if (errorcount > 0) {
+            throw new RuntimeException("SupplementaryCanDisplayUpToTest: failed");
+        }
+    }
+}