Introduce LocalUtil and getLayoutDirectionFromLocale() now use likelySubtags

- move code from Configuration to LocaleUtil
- move unit tests

Change-Id: Ic14b0131894a0c5618f00d4acb3edb0daadefe01

1 files changed, 114 insertions, 0 deletions

diff --git a/core/java/android/util/LocaleUtil.java b/core/java/android/util/LocaleUtil.java
new file mode 100644
index 0000000..4511d94
--- /dev/null
+++ b/core/java/android/util/LocaleUtil.java
@@ -0,0 +1,114 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.util;
+
+import java.util.Locale;
+
+import libcore.icu.ICU;
+
+/**
+ * Various utilities for Locales
+ *
+ * @hide
+ */
+public class LocaleUtil {
+
+    private LocaleUtil() { /* cannot be instantiated */ }
+
+    /**
+     * @hide Do not use. Implementation not finished.
+     */
+    public static final int TEXT_LAYOUT_DIRECTION_UNDEFINED_DO_NOT_USE = -1;
+
+    /**
+     * @hide Do not use. Implementation not finished.
+     */
+    public static final int TEXT_LAYOUT_DIRECTION_LTR_DO_NOT_USE = 0;
+
+    /**
+     * @hide Do not use. Implementation not finished.
+     */
+    public static final int TEXT_LAYOUT_DIRECTION_RTL_DO_NOT_USE = 1;
+
+    private static final char UNDERSCORE_CHAR = '_';
+
+    private static String ARAB_SCRIPT_SUBTAG = "Arab";
+    private static String HEBR_SCRIPT_SUBTAG = "Hebr";
+
+    /**
+     * Return the layout direction for a given Locale
+     *
+     * @param locale the Locale for which we want the layout direction. Can be null.
+     * @return the layout direction. This may be one of:
+     * {@link #TEXT_LAYOUT_DIRECTION_UNDEFINED_DO_NOT_USE} or
+     * {@link #TEXT_LAYOUT_DIRECTION_LTR_DO_NOT_USE} or
+     * {@link #TEXT_LAYOUT_DIRECTION_RTL_DO_NOT_USE}.
+     *
+     * Be careful: this code will need to be changed when vertical scripts will be supported
+     *
+     * @hide
+     */
+    public static int getLayoutDirectionFromLocale(Locale locale) {
+        if (locale == null || locale.equals(Locale.ROOT)) {
+            return TEXT_LAYOUT_DIRECTION_UNDEFINED_DO_NOT_USE;
+        }
+
+        final String localeWithSubtags = ICU.addLikelySubtags(locale.toString());
+        if (localeWithSubtags == null) return getLayoutDirectionFromFirstChar(locale);
+
+        // Need to check if we can extract the script subtag. For example, "Latn" in  "en_Latn_US"
+        if (localeWithSubtags.charAt(2) != UNDERSCORE_CHAR ||
+                localeWithSubtags.charAt(7) != UNDERSCORE_CHAR) {
+            return getLayoutDirectionFromFirstChar(locale);
+        }
+        // Extract the script subtag
+        final String scriptSubtag = localeWithSubtags.substring(3, 7);
+
+        if (scriptSubtag.equalsIgnoreCase(ARAB_SCRIPT_SUBTAG) ||
+                scriptSubtag.equalsIgnoreCase(HEBR_SCRIPT_SUBTAG)) {
+            return TEXT_LAYOUT_DIRECTION_RTL_DO_NOT_USE;
+        }
+        return TEXT_LAYOUT_DIRECTION_LTR_DO_NOT_USE;
+    }
+
+    /**
+     * Fallback algorithm to detect the locale direction. Rely on the fist char of the
+     * localized locale name. This will not work if the localized locale name is in English
+     * (this is the case for ICU 4.4 and "Urdu" script)
+     *
+     * @param locale
+     * @return the layout direction. This may be one of:
+     * {@link #TEXT_LAYOUT_DIRECTION_UNDEFINED_DO_NOT_USE} or
+     * {@link #TEXT_LAYOUT_DIRECTION_LTR_DO_NOT_USE} or
+     * {@link #TEXT_LAYOUT_DIRECTION_RTL_DO_NOT_USE}.
+     *
+     * Be careful: this code will need to be changed when vertical scripts will be supported
+     *
+     * @hide
+     */
+    private static int getLayoutDirectionFromFirstChar(Locale locale) {
+        switch(Character.getDirectionality(locale.getDisplayName(locale).charAt(0))) {
+            case Character.DIRECTIONALITY_LEFT_TO_RIGHT:
+                return TEXT_LAYOUT_DIRECTION_LTR_DO_NOT_USE;
+            case Character.DIRECTIONALITY_RIGHT_TO_LEFT:
+            case Character.DIRECTIONALITY_RIGHT_TO_LEFT_ARABIC:
+                return TEXT_LAYOUT_DIRECTION_RTL_DO_NOT_USE;
+            default:
+                return TEXT_LAYOUT_DIRECTION_UNDEFINED_DO_NOT_USE;
+        }
+    }
+}