/*

 * 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.  Sun designates this

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

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 *

 */

/*

 * (C) Copyright IBM Corp. 1999,  All rights reserved.

 */

package sun.font;

import java.awt.Font;

import java.awt.GraphicsEnvironment;

import java.awt.font.TextAttribute;

import java.util.ArrayList;

import java.util.Map;

import sun.text.CodePointIterator;

/**

 * This class maps an individual character to a Font family which can

 * display it.  The character-to-Font mapping does not depend on the

 * character's context, so a particular character will be mapped to the

 * same font family each time.

 * <p>

 * Typically, clients will call getIndexFor(char) for each character

 * in a style run.  When getIndexFor() returns a different value from

 * ones seen previously, the characters up to that point will be assigned

 * a font obtained from getFont().

 */

public final class FontResolver {

    // An array of all fonts available to the runtime.  The fonts

    // will be searched in order.

    private Font[] allFonts;

    private Font[] supplementaryFonts;

    private int[]  supplementaryIndices;

    // Default size of Fonts (if created from an empty Map, for instance).

    private static final int DEFAULT_SIZE = 12; // from Font

    private Font defaultFont = new Font(Font.DIALOG, Font.PLAIN, DEFAULT_SIZE);

    // The results of previous lookups are cached in a two-level

    // table.  The value for a character c is found in:

    //     blocks[c>>SHIFT][c&MASK]

    // although the second array is only allocated when needed.

    // A 0 value means the character's font has not been looked up.

    // A positive value means the character's font is in the allFonts

    // array at index (value-1).

    private static final int SHIFT = 9;

    private static final int BLOCKSIZE = 1<<(16-SHIFT);

    private static final int MASK = BLOCKSIZE-1;

    private int[][] blocks = new int[1<<SHIFT][];

    private FontResolver() {

    }

    private Font[] getAllFonts() {

        if (allFonts == null) {

            allFonts =

            GraphicsEnvironment.getLocalGraphicsEnvironment().getAllFonts();

            for (int i=0; i < allFonts.length; i++) {

                allFonts[i] = allFonts[i].deriveFont((float)DEFAULT_SIZE);

            }

        }

        return allFonts;

    }

    /**

     * Search fonts in order, and return "1" to indicate its in the default

     * font, (or not found at all),  or the index of the first font

     * which can display the given character, plus 2, if it is not

     * in the default font.

     */

    private int getIndexFor(char c) {

        if (defaultFont.canDisplay(c)) {

            return 1;

        }

        for (int i=0; i < getAllFonts().length; i++) {

            if (allFonts[i].canDisplay(c)) {

                return i+2;

            }

        }

        return 1;

    }

    private Font [] getAllSCFonts() {

        if (supplementaryFonts == null) {

            ArrayList<Font> fonts = new ArrayList<Font>();

            ArrayList<Integer> indices = new ArrayList<Integer>();

            for (int i=0; i<getAllFonts().length; i++) {

                Font font = allFonts[i];

                Font2D font2D = FontManager.getFont2D(font);

                if (font2D.hasSupplementaryChars()) {

                    fonts.add(font);

                    indices.add(Integer.valueOf(i));

                }

            }

            int len = fonts.size();

            supplementaryIndices = new int[len];

            for (int i=0; i<len; i++) {

                supplementaryIndices[i] = indices.get(i);

            }

            supplementaryFonts = fonts.toArray(new Font[len]);

        }

        return supplementaryFonts;

    }

    /* This method is called only for character codes >= 0x10000 - which

     * are assumed to be legal supplementary characters.

     * It looks first at the default font (to avoid calling getAllFonts if at

     * all possible) and if that doesn't map the code point, it scans

     * just the fonts that may contain supplementary characters.

     * The index that is returned is into the "allFonts" array so that

     * callers see the same value for both supplementary and base chars.

     */

    private int getIndexFor(int cp) {

        if (defaultFont.canDisplay(cp)) {

            return 1;

        }

        for (int i = 0; i < getAllSCFonts().length; i++) {

            if (supplementaryFonts[i].canDisplay(cp)) {

                return supplementaryIndices[i]+2;

            }

        }

        return 1;

    }

    /**

     * Return an index for the given character.  The index identifies a

     * font family to getFont(), and has no other inherent meaning.

     * @param c the character to map

     * @return a value for consumption by getFont()

     * @see #getFont

     */

    public int getFontIndex(char c) {

        int blockIndex = c>>SHIFT;

        int[] block = blocks[blockIndex];

        if (block == null) {

            block = new int[BLOCKSIZE];

            blocks[blockIndex] = block;

        }

        int index = c & MASK;

        if (block[index] == 0) {

            block[index] = getIndexFor(c);

        }

        return block[index];

    }

    public int getFontIndex(int cp) {

        if (cp < 0x10000) {

            return getFontIndex((char)cp);

        }

        return getIndexFor(cp);

    }

    /**

     * Determines the font index for the code point at the current position in the

     * iterator, then advances the iterator to the first code point that has

     * a different index or until the iterator is DONE, and returns the font index.

     * @param iter a code point iterator, this will be advanced past any code

     *             points that have the same font index

     * @return the font index for the initial code point found, or 1 if the iterator

     * was empty.

     */

    public int nextFontRunIndex(CodePointIterator iter) {

        int cp = iter.next();

        int fontIndex = 1;

        if (cp != CodePointIterator.DONE) {

            fontIndex = getFontIndex(cp);

            while ((cp = iter.next()) != CodePointIterator.DONE) {

                if (getFontIndex(cp) != fontIndex) {

                    iter.prev();

                    break;

                }

            }

        }

        return fontIndex;

    }

    /**

     * Return a Font from a given font index with properties

     * from attributes.  The font index, which should have been produced

     * by getFontIndex(), determines a font family.  The size and style

     * of the Font reflect the properties in attributes.  Any Font or

     * font family specifications in attributes are ignored, on the

     * assumption that clients have already handled them.

     * @param index an index from getFontIndex() which determines the

     *        font family

     * @param attributes a Map from which the size and style of the Font

     *        are determined.  The default size is 12 and the default style

     *        is Font.PLAIN

     * @see #getFontIndex

     */

    public Font getFont(int index, Map attributes) {

        Font font = defaultFont;

        if (index >= 2) {

            font = allFonts[index-2];

        }

        return font.deriveFont(attributes);

    }

    private static FontResolver INSTANCE;

    /**

     * Return a shared instance of FontResolver.

     */

    public static FontResolver getInstance() {

        if (INSTANCE == null) {

            INSTANCE = new FontResolver();

        }

        return INSTANCE;

    }

}