/* * Copyright (C) 2012 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 com.android.inputmethod.latin.utils; import java.util.Locale; import java.util.TreeMap; /** * A class to help with handling different writing scripts. */ public class ScriptUtils { // Used for hardware keyboards public static final int SCRIPT_UNKNOWN = -1; // TODO: should we use ISO 15924 identifiers instead? public static final int SCRIPT_LATIN = 0; public static final int SCRIPT_CYRILLIC = 1; public static final int SCRIPT_GREEK = 2; public static final int SCRIPT_ARABIC = 3; public static final int SCRIPT_HEBREW = 4; public static final int SCRIPT_ARMENIAN = 5; public static final int SCRIPT_GEORGIAN = 6; public static final int SCRIPT_KHMER = 7; public static final int SCRIPT_LAO = 8; public static final TreeMap mSpellCheckerLanguageToScript; static { // List of the supported languages and their associated script. We won't check // words written in another script than the selected script, because we know we // don't have those in our dictionary so we will underline everything and we // will never have any suggestions, so it makes no sense checking them, and this // is done in {@link #shouldFilterOut}. Also, the script is used to choose which // proximity to pass to the dictionary descent algorithm. // IMPORTANT: this only contains languages - do not write countries in there. // Only the language is searched from the map. mSpellCheckerLanguageToScript = new TreeMap<>(); mSpellCheckerLanguageToScript.put("cs", SCRIPT_LATIN); mSpellCheckerLanguageToScript.put("da", SCRIPT_LATIN); mSpellCheckerLanguageToScript.put("de", SCRIPT_LATIN); mSpellCheckerLanguageToScript.put("el", SCRIPT_GREEK); mSpellCheckerLanguageToScript.put("en", SCRIPT_LATIN); mSpellCheckerLanguageToScript.put("es", SCRIPT_LATIN); mSpellCheckerLanguageToScript.put("fi", SCRIPT_LATIN); mSpellCheckerLanguageToScript.put("fr", SCRIPT_LATIN); mSpellCheckerLanguageToScript.put("hr", SCRIPT_LATIN); mSpellCheckerLanguageToScript.put("it", SCRIPT_LATIN); mSpellCheckerLanguageToScript.put("lt", SCRIPT_LATIN); mSpellCheckerLanguageToScript.put("lv", SCRIPT_LATIN); mSpellCheckerLanguageToScript.put("nb", SCRIPT_LATIN); mSpellCheckerLanguageToScript.put("nl", SCRIPT_LATIN); mSpellCheckerLanguageToScript.put("pt", SCRIPT_LATIN); mSpellCheckerLanguageToScript.put("sl", SCRIPT_LATIN); mSpellCheckerLanguageToScript.put("ru", SCRIPT_CYRILLIC); } /* * Returns whether the code point is a letter that makes sense for the specified * locale for this spell checker. * The dictionaries supported by Latin IME are described in res/xml/spellchecker.xml * and is limited to EFIGS languages and Russian. * Hence at the moment this explicitly tests for Cyrillic characters or Latin characters * as appropriate, and explicitly excludes CJK, Arabic and Hebrew characters. */ public static boolean isLetterPartOfScript(final int codePoint, final int scriptId) { switch (scriptId) { case SCRIPT_LATIN: // Our supported latin script dictionaries (EFIGS) at the moment only include // characters in the C0, C1, Latin Extended A and B, IPA extensions unicode // blocks. As it happens, those are back-to-back in the code range 0x40 to 0x2AF, // so the below is a very efficient way to test for it. As for the 0-0x3F, it's // excluded from isLetter anyway. return codePoint <= 0x2AF && Character.isLetter(codePoint); case SCRIPT_CYRILLIC: // All Cyrillic characters are in the 400~52F block. There are some in the upper // Unicode range, but they are archaic characters that are not used in modern // Russian and are not used by our dictionary. return codePoint >= 0x400 && codePoint <= 0x52F && Character.isLetter(codePoint); case SCRIPT_GREEK: // Greek letters are either in the 370~3FF range (Greek & Coptic), or in the // 1F00~1FFF range (Greek extended). Our dictionary contains both sort of characters. // Our dictionary also contains a few words with 0xF2; it would be best to check // if that's correct, but a web search does return results for these words so // they are probably okay. return (codePoint >= 0x370 && codePoint <= 0x3FF) || (codePoint >= 0x1F00 && codePoint <= 0x1FFF) || codePoint == 0xF2; case SCRIPT_ARABIC: // Arabic letters can be in any of the following blocks: // Arabic U+0600..U+06FF // Arabic Supplement U+0750..U+077F // Arabic Extended-A U+08A0..U+08FF // Arabic Presentation Forms-A U+FB50..U+FDFF // Arabic Presentation Forms-B U+FE70..U+FEFF return (codePoint >= 0x600 && codePoint <= 0x6FF) || (codePoint >= 0x750 && codePoint <= 0x77F) || (codePoint >= 0x8A0 && codePoint <= 0x8FF) || (codePoint >= 0xFB50 && codePoint <= 0xFDFF) || (codePoint >= 0xFE70 && codePoint <= 0xFEFF); case SCRIPT_HEBREW: // Hebrew letters are in the Hebrew unicode block, which spans from U+0590 to U+05FF, // or in the Alphabetic Presentation Forms block, U+FB00..U+FB4F, but only in the // Hebrew part of that block, which is U+FB1D..U+FB4F. return (codePoint >= 0x590 && codePoint <= 0x5FF || codePoint >= 0xFB1D && codePoint <= 0xFB4F); case SCRIPT_ARMENIAN: // Armenian letters are in the Armenian unicode block, U+0530..U+058F and // Alphabetic Presentation Forms block, U+FB00..U+FB4F, but only in the Armenian part // of that block, which is U+FB13..U+FB17. return (codePoint >= 0x530 && codePoint <= 0x58F || codePoint >= 0xFB13 && codePoint <= 0xFB17); case SCRIPT_GEORGIAN: // Georgian letters are in the Georgian unicode block, U+10A0..U+10FF, // or Georgian supplement block, U+2D00..U+2D2F return (codePoint >= 0x10A0 && codePoint <= 0x10FF || codePoint >= 0x2D00 && codePoint <= 0x2D2F); case SCRIPT_KHMER: // Khmer letters are in unicode block U+1780..U+17FF, and the Khmer symbols block // is U+19E0..U+19FF return (codePoint >= 0x1780 && codePoint <= 0x17FF || codePoint >= 0x19E0 && codePoint <= 0x19FF); case SCRIPT_LAO: // The Lao block is U+0E80..U+0EFF return (codePoint >= 0xE80 && codePoint <= 0xEFF); case SCRIPT_UNKNOWN: return true; default: // Should never come here throw new RuntimeException("Impossible value of script: " + scriptId); } } public static int getScriptFromSpellCheckerLocale(final Locale locale) { final Integer script = mSpellCheckerLanguageToScript.get(locale.getLanguage()); if (null == script) { throw new RuntimeException("We have been called with an unsupported language: \"" + locale.getLanguage() + "\". Framework bug?"); } return script; } }