1   /*
    2    * Licensed to the Apache Software Foundation (ASF) under one or more
    3    * contributor license agreements.  See the NOTICE file distributed with
    4    * this work for additional information regarding copyright ownership.
    5    * The ASF licenses this file to You under the Apache License, Version 2.0
    6    * (the "License"); you may not use this file except in compliance with
    7    * the License.  You may obtain a copy of the License at
    8    *
    9    *      http://www.apache.org/licenses/LICENSE-2.0
   10    *
   11    * Unless required by applicable law or agreed to in writing, software
   12    * distributed under the License is distributed on an "AS IS" BASIS,
   13    * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   14    * See the License for the specific language governing permissions and
   15    * limitations under the License.
   16    */
   17   package org.apache.fontbox.encoding;
   18   
   19   import java.io.IOException;
   20   
   21   import java.util.HashMap;
   22   import java.util.Map;
   23   
   24   /**
   25    * This is an interface to a text encoder.
   26    *
   27    * @author Ben Litchfield
   28    * @version $Revision: 1.1 $
   29    */
   30   public abstract class Encoding
   31   {
   32   
   33   
   34       /**
   35        * This is a mapping from a character code to a character name.
   36        */
   37       protected Map<Integer,String> codeToName = new HashMap<Integer,String>();
   38       /**
   39        * This is a mapping from a character name to a character code.
   40        */
   41       protected Map<String,Integer> nameToCode = new HashMap<String,Integer>();
   42   
   43       private static final Map<String,String> NAME_TO_CHARACTER = new HashMap<String,String>();
   44       private static final Map<String,String> CHARACTER_TO_NAME = new HashMap<String,String>();
   45   
   46       static
   47       {
   48       }
   49   
   50   
   51       /**
   52        * This will add a character encoding.
   53        *
   54        * @param code The character code that matches the character.
   55        * @param name The name of the character.
   56        */
   57       protected void addCharacterEncoding( int code, String name )
   58       {
   59           codeToName.put( code, name );
   60           nameToCode.put( name, code );
   61       }
   62   
   63       /**
   64        * This will get the character code for the name.
   65        *
   66        * @param name The name of the character.
   67        *
   68        * @return The code for the character.
   69        *
   70        * @throws IOException If there is no character code for the name.
   71        */
   72       public int getCode( String name ) throws IOException
   73       {
   74           Integer code = nameToCode.get( name );
   75           if( code == null )
   76           {
   77               throw new IOException( "No character code for character name '" + name + "'" );
   78           }
   79           return code.intValue();
   80       }
   81   
   82       /**
   83        * This will take a character code and get the name from the code.
   84        *
   85        * @param code The character code.
   86        *
   87        * @return The name of the character.
   88        *
   89        * @throws IOException If there is no name for the code.
   90        */
   91       public String getName( int code ) throws IOException
   92       {
   93           String name = codeToName.get( code );
   94           if( name == null )
   95           {
   96               //lets be forgiving for now
   97               name = "space";
   98               //throw new IOException( getClass().getName() +
   99               //                       ": No name for character code '" + code + "'" );
  100           }
  101           return name;
  102       }
  103   
  104       /**
  105        * This will take a character code and get the name from the code.
  106        *
  107        * @param c The character.
  108        *
  109        * @return The name of the character.
  110        *
  111        * @throws IOException If there is no name for the character.
  112        */
  113       public String getNameFromCharacter( char c ) throws IOException
  114       {
  115           String name = CHARACTER_TO_NAME.get( c );
  116           if( name == null )
  117           {
  118               throw new IOException( "No name for character '" + c + "'" );
  119           }
  120           return name;
  121       }
  122   
  123       /**
  124        * This will get the character from the code.
  125        *
  126        * @param code The character code.
  127        *
  128        * @return The printable character for the code.
  129        *
  130        * @throws IOException If there is not name for the character.
  131        */
  132       public String getCharacter( int code ) throws IOException
  133       {
  134           return getCharacter( getName( code ) );
  135       }
  136   
  137       /**
  138        * This will get the character from the name.
  139        *
  140        * @param name The name of the character.
  141        *
  142        * @return The printable character for the code.
  143        */
  144       public static String getCharacter( String name )
  145       {
  146           String character = NAME_TO_CHARACTER.get( name );
  147           if( character == null )
  148           {
  149               character = name;
  150           }
  151           return character;
  152       }
  153   }