/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 */

/* $Id: AbstractCodePointMapping.java 1616312 2014-08-06 19:19:31Z gadams $ */

package org.apache.fop.fonts;

import java.util.Arrays;

import org.apache.xmlgraphics.fonts.Glyphs;

import org.apache.fop.util.CharUtilities;

Abstract base class for code point mapping classes (1-byte character encodings).
/**
 * Abstract base class for code point mapping classes (1-byte character encodings).
 */
public class AbstractCodePointMapping implements SingleByteEncoding {

    private final String name;
    private char[] latin1Map;
    private char[] characters;
    private char[] codepoints;
    private char[] unicodeMap; //code point to Unicode char
    private String[] charNameMap; //all character names in the encoding

    
Main constructor.
Params:
name – the name of the encoding
table – the table ([code point, unicode scalar value]+) with the mapping/**
     * Main constructor.
     * @param name the name of the encoding
     * @param table the table ([code point, unicode scalar value]+) with the mapping
     */
    public AbstractCodePointMapping(String name, int[] table) {
        this(name, table, null);
    }

    
Extended constructor.
Params:
name – the name of the encoding
table – the table ([code point, unicode scalar value]+) with the mapping
charNameMap – all character names in the encoding (a value of null will be converted
                 to ".notdef")/**
     * Extended constructor.
     * @param name the name of the encoding
     * @param table the table ([code point, unicode scalar value]+) with the mapping
     * @param charNameMap all character names in the encoding (a value of null will be converted
     *                  to ".notdef")
     */
    public AbstractCodePointMapping(String name, int[] table, String[] charNameMap) {
        this.name = name;
        buildFromTable(table);
        if (charNameMap != null) {
            this.charNameMap = new String[256];
            for (int i = 0; i < 256; i++) {
                String charName = charNameMap[i];
                if (charName == null) {
                    this.charNameMap[i] = Glyphs.NOTDEF;
                } else {
                    this.charNameMap[i] = charName;
                }
            }
        }
    }

    
Builds the internal lookup structures based on a given table.
Params:
table – the table ([code point, unicode scalar value]+) with the mapping/**
     * Builds the internal lookup structures based on a given table.
     * @param table the table ([code point, unicode scalar value]+) with the mapping
     */
    protected void buildFromTable(int[] table) {
        int nonLatin1 = 0;
        latin1Map = new char[256];
        unicodeMap = new char[256];
        Arrays.fill(unicodeMap, CharUtilities.NOT_A_CHARACTER);
        for (int i = 0; i < table.length; i += 2) {
            char unicode = (char)table[i + 1];
            if (unicode < 256) {
                if (latin1Map[unicode] == 0) {
                    latin1Map[unicode] = (char) table[i];
                }
            } else {
                ++nonLatin1;
            }
            if (unicodeMap[table[i]] == CharUtilities.NOT_A_CHARACTER) {
                unicodeMap[table[i]] = unicode;
            }
        }
        characters = new char[nonLatin1];
        codepoints = new char[nonLatin1];
        int top = 0;
        for (int i = 0; i < table.length; i += 2) {
            char c = (char) table[i + 1];
            if (c >= 256) {
               ++top;
               for (int j = top - 1; j >= 0; --j) {
                   if (j > 0 && characters[j - 1] >= c) {
                       characters[j] = characters[j - 1];
                       codepoints[j] = codepoints[j - 1];
                   } else {
                       characters[j] = c;
                       codepoints[j] = (char) table[i];
                       break;
                   }
               }
            }
        }
    }

    
{@inheritDoc} /** {@inheritDoc} */
    public String getName() {
        return this.name;
    }

    
{@inheritDoc} /** {@inheritDoc} */
    public final char mapChar(char c) {
        if (c < 256) {
            char latin1 = latin1Map[c];
            if (latin1 > 0) {
                return latin1;
            }
        }
        int bot = 0;
        int top = characters.length - 1;
        while (top >= bot) {
            assert bot < 65536;
            assert top < 65536;
            int mid = (bot + top) >>> 1;
            char mc = characters[mid];

            if (c == mc) {
                return codepoints[mid];
            } else if (c < mc) {
                top = mid - 1;
            } else {
                bot = mid + 1;
            }
        }
        return NOT_FOUND_CODE_POINT;
    }

    
Returns the main Unicode value that is associated with the given code point in the encoding.
Note that multiple Unicode values can theoretically be mapped to one code point in the
encoding.
Params:
idx – the code point in the encoding
Returns:
the Unicode value (or \uFFFF (NOT A CHARACTER) if no Unicode value is at that point)/**
     * Returns the main Unicode value that is associated with the given code point in the encoding.
     * Note that multiple Unicode values can theoretically be mapped to one code point in the
     * encoding.
     * @param idx the code point in the encoding
     * @return the Unicode value (or \uFFFF (NOT A CHARACTER) if no Unicode value is at that point)
     */
    public final char getUnicodeForIndex(int idx) {
        return this.unicodeMap[idx];
    }

    
{@inheritDoc} /** {@inheritDoc} */
    public final char[] getUnicodeCharMap() {
        char[] copy = new char[this.unicodeMap.length];
        System.arraycopy(this.unicodeMap, 0, copy, 0, this.unicodeMap.length);
        return copy;
    }

    
Returns the index of a character/glyph with the given name. Note that this
method is relatively slow and should only be used for fallback operations.
Params:
charName – the character name
Returns:
the index of the character in the encoding or -1 if it doesn't exist/**
     * Returns the index of a character/glyph with the given name. Note that this
     * method is relatively slow and should only be used for fallback operations.
     * @param charName the character name
     * @return the index of the character in the encoding or -1 if it doesn't exist
     */
    public short getCodePointForGlyph(String charName) {
        String[] names = this.charNameMap;
        if (names == null) {
            names = getCharNameMap();
        }
        for (short i = 0, c = (short)names.length; i < c; i++) {
            if (names[i].equals(charName)) {
                return i;
            }
        }
        return -1;
    }

    public String getNameFromCodePoint(int idx) {
        return getCharNameMap()[idx];
    }

    
{@inheritDoc} /** {@inheritDoc} */
    public String[] getCharNameMap() {
        if (this.charNameMap != null) {
            String[] copy = new String[this.charNameMap.length];
            System.arraycopy(this.charNameMap, 0, copy, 0, this.charNameMap.length);
            return copy;
        } else {
            //Note: this is suboptimal but will probably never be used.
            String[] derived = new String[256];
            Arrays.fill(derived, Glyphs.NOTDEF);
            for (int i = 0; i < 256; i++) {
                char c = getUnicodeForIndex(i);
                if (c != CharUtilities.NOT_A_CHARACTER) {
                    String charName = Glyphs.charToGlyphName(c);
                    if (charName.length() > 0) {
                        derived[i] = charName;
                    }
                }
            }
            return derived;
        }
    }

    
{@inheritDoc} /** {@inheritDoc} */
    @Override
    public String toString() {
        return getName();
    }
}