/*

 * Copyright (c) 2003, 2013, 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.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * 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.

 */

package java.lang;

import java.text.BreakIterator;

import java.util.HashSet;

import java.util.Hashtable;

import java.util.Iterator;

import java.util.Locale;

import sun.text.Normalizer;

/**

 * This is a utility class for <code>String.toLowerCase()</code> and

 * <code>String.toUpperCase()</code>, that handles special casing with

 * conditions.  In other words, it handles the mappings with conditions

 * that are defined in

 * <a href="http://www.unicode.org/Public/UNIDATA/SpecialCasing.txt">Special

 * Casing Properties</a> file.

 * <p>

 * Note that the unconditional case mappings (including 1:M mappings)

 * are handled in <code>Character.toLower/UpperCase()</code>.

 */

final class ConditionalSpecialCasing {

    // context conditions.

    static final int FINAL_CASED =              1;

    static final int AFTER_SOFT_DOTTED =        2;

    static final int MORE_ABOVE =               3;

    static final int AFTER_I =                  4;

    static final int NOT_BEFORE_DOT =           5;

    // combining class definitions

    static final int COMBINING_CLASS_ABOVE = 230;

    // Special case mapping entries

    static Entry[] entry = {

        //# ================================================================================

        //# Conditional mappings

        //# ================================================================================

        new Entry(0x03A3, new char[]{0x03C2}, new char[]{0x03A3}, null, FINAL_CASED), // # GREEK CAPITAL LETTER SIGMA

        new Entry(0x0130, new char[]{0x0069, 0x0307}, new char[]{0x0130}, null, 0), // # LATIN CAPITAL LETTER I WITH DOT ABOVE

        //# ================================================================================

        //# Locale-sensitive mappings

        //# ================================================================================

        //# Lithuanian

        new Entry(0x0307, new char[]{0x0307}, new char[]{}, "lt",  AFTER_SOFT_DOTTED), // # COMBINING DOT ABOVE

        new Entry(0x0049, new char[]{0x0069, 0x0307}, new char[]{0x0049}, "lt", MORE_ABOVE), // # LATIN CAPITAL LETTER I

        new Entry(0x004A, new char[]{0x006A, 0x0307}, new char[]{0x004A}, "lt", MORE_ABOVE), // # LATIN CAPITAL LETTER J

        new Entry(0x012E, new char[]{0x012F, 0x0307}, new char[]{0x012E}, "lt", MORE_ABOVE), // # LATIN CAPITAL LETTER I WITH OGONEK

        new Entry(0x00CC, new char[]{0x0069, 0x0307, 0x0300}, new char[]{0x00CC}, "lt", 0), // # LATIN CAPITAL LETTER I WITH GRAVE

        new Entry(0x00CD, new char[]{0x0069, 0x0307, 0x0301}, new char[]{0x00CD}, "lt", 0), // # LATIN CAPITAL LETTER I WITH ACUTE

        new Entry(0x0128, new char[]{0x0069, 0x0307, 0x0303}, new char[]{0x0128}, "lt", 0), // # LATIN CAPITAL LETTER I WITH TILDE

        //# ================================================================================

        //# Turkish and Azeri

        new Entry(0x0130, new char[]{0x0069}, new char[]{0x0130}, "tr", 0), // # LATIN CAPITAL LETTER I WITH DOT ABOVE

        new Entry(0x0130, new char[]{0x0069}, new char[]{0x0130}, "az", 0), // # LATIN CAPITAL LETTER I WITH DOT ABOVE

        new Entry(0x0307, new char[]{}, new char[]{0x0307}, "tr", AFTER_I), // # COMBINING DOT ABOVE

        new Entry(0x0307, new char[]{}, new char[]{0x0307}, "az", AFTER_I), // # COMBINING DOT ABOVE

        new Entry(0x0049, new char[]{0x0131}, new char[]{0x0049}, "tr", NOT_BEFORE_DOT), // # LATIN CAPITAL LETTER I

        new Entry(0x0049, new char[]{0x0131}, new char[]{0x0049}, "az", NOT_BEFORE_DOT), // # LATIN CAPITAL LETTER I

        new Entry(0x0069, new char[]{0x0069}, new char[]{0x0130}, "tr", 0), // # LATIN SMALL LETTER I

        new Entry(0x0069, new char[]{0x0069}, new char[]{0x0130}, "az", 0)  // # LATIN SMALL LETTER I

    };

    // A hash table that contains the above entries

    static Hashtable<Integer, HashSet<Entry>> entryTable = new Hashtable<>();

    static {

        // create hashtable from the entry

        for (Entry cur : entry) {

            Integer cp = cur.getCodePoint();

            HashSet<Entry> set = entryTable.get(cp);

            if (set == null) {

                set = new HashSet<>();

                entryTable.put(cp, set);

            }

            set.add(cur);

        }

    }

    static int toLowerCaseEx(String src, int index, Locale locale) {

        char[] result = lookUpTable(src, index, locale, true);

        if (result != null) {

            if (result.length == 1) {

                return result[0];

            } else {

                return Character.ERROR;

            }

        } else {

            // default to Character class' one

            return Character.toLowerCase(src.codePointAt(index));

        }

    }

    static int toUpperCaseEx(String src, int index, Locale locale) {

        char[] result = lookUpTable(src, index, locale, false);

        if (result != null) {

            if (result.length == 1) {

                return result[0];

            } else {

                return Character.ERROR;

            }

        } else {

            // default to Character class' one

            return Character.toUpperCaseEx(src.codePointAt(index));

        }

    }

    static char[] toLowerCaseCharArray(String src, int index, Locale locale) {

        return lookUpTable(src, index, locale, true);

    }

    static char[] toUpperCaseCharArray(String src, int index, Locale locale) {

        char[] result = lookUpTable(src, index, locale, false);

        if (result != null) {

            return result;

        } else {

            return Character.toUpperCaseCharArray(src.codePointAt(index));

        }

    }

    private static char[] lookUpTable(String src, int index, Locale locale, boolean bLowerCasing) {

        HashSet<Entry> set = entryTable.get(src.codePointAt(index));

        char[] ret = null;

        if (set != null) {

            Iterator<Entry> iter = set.iterator();

            String currentLang = locale.getLanguage();

            while (iter.hasNext()) {

                Entry entry = iter.next();

                String conditionLang = entry.getLanguage();

                if (((conditionLang == null) || (conditionLang.equals(currentLang))) &&

                        isConditionMet(src, index, locale, entry.getCondition())) {

                    ret = bLowerCasing ? entry.getLowerCase() : entry.getUpperCase();

                    if (conditionLang != null) {

                        break;

                    }

                }

            }

        }

        return ret;

    }

    private static boolean isConditionMet(String src, int index, Locale locale, int condition) {

        switch (condition) {

        case FINAL_CASED:

            return isFinalCased(src, index, locale);

        case AFTER_SOFT_DOTTED:

            return isAfterSoftDotted(src, index);

        case MORE_ABOVE:

            return isMoreAbove(src, index);

        case AFTER_I:

            return isAfterI(src, index);

        case NOT_BEFORE_DOT:

            return !isBeforeDot(src, index);

        default:

            return true;

        }

    }

    /**

     * Implements the "Final_Cased" condition

     *

     * Specification: Within the closest word boundaries containing C, there is a cased

     * letter before C, and there is no cased letter after C.

     *

     * Regular Expression:

     *   Before C: [{cased==true}][{wordBoundary!=true}]*

     *   After C: !([{wordBoundary!=true}]*[{cased}])

     */

    private static boolean isFinalCased(String src, int index, Locale locale) {

        BreakIterator wordBoundary = BreakIterator.getWordInstance(locale);

        wordBoundary.setText(src);

        int ch;

        // Look for a preceding 'cased' letter

        for (int i = index; (i >= 0) && !wordBoundary.isBoundary(i);

                i -= Character.charCount(ch)) {

            ch = src.codePointBefore(i);

            if (isCased(ch)) {

                int len = src.length();

                // Check that there is no 'cased' letter after the index

                for (i = index + Character.charCount(src.codePointAt(index));

                        (i < len) && !wordBoundary.isBoundary(i);

                        i += Character.charCount(ch)) {

                    ch = src.codePointAt(i);

                    if (isCased(ch)) {

                        return false;

                    }

                }

                return true;

            }

        }

        return false;

    }

    /**

     * Implements the "After_I" condition

     *

     * Specification: The last preceding base character was an uppercase I,

     * and there is no intervening combining character class 230 (ABOVE).

     *

     * Regular Expression:

     *   Before C: [I]([{cc!=230}&{cc!=0}])*

     */

    private static boolean isAfterI(String src, int index) {

        int ch;

        int cc;

        // Look for the last preceding base character

        for (int i = index; i > 0; i -= Character.charCount(ch)) {

            ch = src.codePointBefore(i);

            if (ch == 'I') {

                return true;

            } else {

                cc = Normalizer.getCombiningClass(ch);

                if ((cc == 0) || (cc == COMBINING_CLASS_ABOVE)) {

                    return false;

                }

            }

        }

        return false;

    }

    /**

     * Implements the "After_Soft_Dotted" condition

     *

     * Specification: The last preceding character with combining class

     * of zero before C was Soft_Dotted, and there is no intervening

     * combining character class 230 (ABOVE).

     *

     * Regular Expression:

     *   Before C: [{Soft_Dotted==true}]([{cc!=230}&{cc!=0}])*

     */

    private static boolean isAfterSoftDotted(String src, int index) {

        int ch;

        int cc;

        // Look for the last preceding character

        for (int i = index; i > 0; i -= Character.charCount(ch)) {

            ch = src.codePointBefore(i);

            if (isSoftDotted(ch)) {

                return true;

            } else {

                cc = Normalizer.getCombiningClass(ch);

                if ((cc == 0) || (cc == COMBINING_CLASS_ABOVE)) {

                    return false;

                }

            }

        }

        return false;

    }

    /**

     * Implements the "More_Above" condition

     *

     * Specification: C is followed by one or more characters of combining

     * class 230 (ABOVE) in the combining character sequence.

     *

     * Regular Expression:

     *   After C: [{cc!=0}]*[{cc==230}]

     */

    private static boolean isMoreAbove(String src, int index) {

        int ch;

        int cc;

        int len = src.length();

        // Look for a following ABOVE combining class character

        for (int i = index + Character.charCount(src.codePointAt(index));

                i < len; i += Character.charCount(ch)) {

            ch = src.codePointAt(i);

            cc = Normalizer.getCombiningClass(ch);

            if (cc == COMBINING_CLASS_ABOVE) {

                return true;

            } else if (cc == 0) {

                return false;

            }

        }

        return false;

    }

    /**

     * Implements the "Before_Dot" condition

     *

     * Specification: C is followed by <code>U+0307 COMBINING DOT ABOVE</code>.

     * Any sequence of characters with a combining class that is

     * neither 0 nor 230 may intervene between the current character

     * and the combining dot above.

     *

     * Regular Expression:

     *   After C: ([{cc!=230}&{cc!=0}])*[\u0307]

     */

    private static boolean isBeforeDot(String src, int index) {

        int ch;

        int cc;

        int len = src.length();

        // Look for a following COMBINING DOT ABOVE

        for (int i = index + Character.charCount(src.codePointAt(index));

                i < len; i += Character.charCount(ch)) {

            ch = src.codePointAt(i);

            if (ch == '\u0307') {

                return true;

            } else {

                cc = Normalizer.getCombiningClass(ch);

                if ((cc == 0) || (cc == COMBINING_CLASS_ABOVE)) {

                    return false;

                }

            }

        }

        return false;

    }

    /**

     * Examines whether a character is 'cased'.

     *

     * A character C is defined to be 'cased' if and only if at least one of

     * following are true for C: uppercase==true, or lowercase==true, or

     * general_category==titlecase_letter.

     *

     * The uppercase and lowercase property values are specified in the data

     * file DerivedCoreProperties.txt in the Unicode Character Database.

     */

    private static boolean isCased(int ch) {

        int type = Character.getType(ch);

        if (type == Character.LOWERCASE_LETTER ||

                type == Character.UPPERCASE_LETTER ||

                type == Character.TITLECASE_LETTER) {

            return true;

        } else {

            // Check for Other_Lowercase and Other_Uppercase

            //

            if ((ch >= 0x02B0) && (ch <= 0x02B8)) {

                // MODIFIER LETTER SMALL H..MODIFIER LETTER SMALL Y

                return true;

            } else if ((ch >= 0x02C0) && (ch <= 0x02C1)) {

                // MODIFIER LETTER GLOTTAL STOP..MODIFIER LETTER REVERSED GLOTTAL STOP

                return true;

            } else if ((ch >= 0x02E0) && (ch <= 0x02E4)) {

                // MODIFIER LETTER SMALL GAMMA..MODIFIER LETTER SMALL REVERSED GLOTTAL STOP

                return true;

            } else if (ch == 0x0345) {

                // COMBINING GREEK YPOGEGRAMMENI

                return true;

            } else if (ch == 0x037A) {

                // GREEK YPOGEGRAMMENI

                return true;

            } else if ((ch >= 0x1D2C) && (ch <= 0x1D61)) {

                // MODIFIER LETTER CAPITAL A..MODIFIER LETTER SMALL CHI

                return true;

            } else if ((ch >= 0x2160) && (ch <= 0x217F)) {

                // ROMAN NUMERAL ONE..ROMAN NUMERAL ONE THOUSAND

                // SMALL ROMAN NUMERAL ONE..SMALL ROMAN NUMERAL ONE THOUSAND

                return true;

            } else if ((ch >= 0x24B6) && (ch <= 0x24E9)) {

                // CIRCLED LATIN CAPITAL LETTER A..CIRCLED LATIN CAPITAL LETTER Z

                // CIRCLED LATIN SMALL LETTER A..CIRCLED LATIN SMALL LETTER Z

                return true;

            } else {

                return false;

            }

        }

    }

    private static boolean isSoftDotted(int ch) {

        switch (ch) {

        case 0x0069: // Soft_Dotted # L&       LATIN SMALL LETTER I

        case 0x006A: // Soft_Dotted # L&       LATIN SMALL LETTER J

        case 0x012F: // Soft_Dotted # L&       LATIN SMALL LETTER I WITH OGONEK

        case 0x0268: // Soft_Dotted # L&       LATIN SMALL LETTER I WITH STROKE

        case 0x0456: // Soft_Dotted # L&       CYRILLIC SMALL LETTER BYELORUSSIAN-UKRAINIAN I

        case 0x0458: // Soft_Dotted # L&       CYRILLIC SMALL LETTER JE

        case 0x1D62: // Soft_Dotted # L&       LATIN SUBSCRIPT SMALL LETTER I

        case 0x1E2D: // Soft_Dotted # L&       LATIN SMALL LETTER I WITH TILDE BELOW

        case 0x1ECB: // Soft_Dotted # L&       LATIN SMALL LETTER I WITH DOT BELOW

        case 0x2071: // Soft_Dotted # L&       SUPERSCRIPT LATIN SMALL LETTER I

            return true;

        default:

            return false;

        }

    }

    /**

     * An internal class that represents an entry in the Special Casing Properties.

     */

    static class Entry {

        int ch;

        char [] lower;

        char [] upper;

        String lang;

        int condition;

        Entry(int ch, char[] lower, char[] upper, String lang, int condition) {

            this.ch = ch;

            this.lower = lower;

            this.upper = upper;

            this.lang = lang;

            this.condition = condition;

        }

        int getCodePoint() {

            return ch;

        }

        char[] getLowerCase() {

            return lower;

        }

        char[] getUpperCase() {

            return upper;

        }

        String getLanguage() {

            return lang;

        }

        int getCondition() {

            return condition;

        }

    }

}