Encoding.java

/*
 * 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.
 */
package org.apache.fontbox.encoding;

import java.io.IOException;

import java.util.HashMap;
import java.util.Map;

/**
 * This is an interface to a text encoder.
 *
 * @author Ben Litchfield
 * @version $Revision: 1.1 $
 */
public abstract class Encoding
{

    /**
     * Identifies a non-mapped character. 
     */
    private static final String NOTDEF = ".notdef";

    /**
     * This is a mapping from a character code to a character name.
     */
    protected Map<Integer,String> codeToName = new HashMap<Integer,String>();
    /**
     * This is a mapping from a character name to a character code.
     */
    protected Map<String,Integer> nameToCode = new HashMap<String,Integer>();

    private static final Map<String,String> NAME_TO_CHARACTER = new HashMap<String,String>();
    private static final Map<String,String> CHARACTER_TO_NAME = new HashMap<String,String>();

    /**
     * This will add a character encoding.
     *
     * @param code The character code that matches the character.
     * @param name The name of the character.
     */
    protected void addCharacterEncoding( int code, String name )
    {
        codeToName.put( code, name );
        nameToCode.put( name, code );
    }

    /**
     * This will get the character code for the name.
     *
     * @param name The name of the character.
     *
     * @return The code for the character.
     *
     * @throws IOException If there is no character code for the name.
     */
    public int getCode( String name ) throws IOException
    {
        Integer code = nameToCode.get( name );
        if( code == null )
        {
            throw new IOException( "No character code for character name '" + name + "'" );
        }
        return code.intValue();
    }

    /**
     * This will take a character code and get the name from the code.
     *
     * @param code The character code.
     *
     * @return The name of the character.
     *
     * @throws IOException If there is no name for the code.
     */
    public String getName( int code ) throws IOException
    {
        String name = codeToName.get( code );
        if( name == null )
        {
            name = NOTDEF;
        }
        return name;
    }

    /**
     * This will take a character code and get the name from the code.
     *
     * @param c The character.
     *
     * @return The name of the character.
     *
     * @throws IOException If there is no name for the character.
     */
    public String getNameFromCharacter( char c ) throws IOException
    {
        String name = CHARACTER_TO_NAME.get( c );
        if( name == null )
        {
            throw new IOException( "No name for character '" + c + "'" );
        }
        return name;
    }

    /**
     * This will get the character from the code.
     *
     * @param code The character code.
     *
     * @return The printable character for the code.
     *
     * @throws IOException If there is not name for the character.
     */
    public String getCharacter( int code ) throws IOException
    {
        return getCharacter( getName( code ) );
    }

    /**
     * This will get the character from the name.
     *
     * @param name The name of the character.
     *
     * @return The printable character for the code.
     */
    public static String getCharacter( String name )
    {
        String character = NAME_TO_CHARACTER.get( name );
        if( character == null )
        {
            character = name;
        }
        return character;
    }
}