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.pdfbox.encoding;
   18   
   19   import java.io.IOException;
   20   
   21   import org.apache.pdfbox.cos.COSArray;
   22   import org.apache.pdfbox.cos.COSBase;
   23   import org.apache.pdfbox.cos.COSDictionary;
   24   import org.apache.pdfbox.cos.COSName;
   25   import org.apache.pdfbox.cos.COSNumber;
   26   
   27   /**
   28    * This will perform the encoding from a dictionary.
   29    *
   30    * @author <a href="mailto:ben@benlitchfield.com">Ben Litchfield</a>
   31    * @version $Revision: 1.13 $
   32    */
   33   public class DictionaryEncoding extends Encoding
   34   {
   35       private COSDictionary encoding = null;
   36   
   37       /**
   38        * Constructor.
   39        *
   40        * @param fontEncoding The encoding dictionary.
   41        *
   42        * @throws IOException If there is a problem getting the base font.
   43        */
   44       public DictionaryEncoding( COSDictionary fontEncoding ) throws IOException
   45       {
   46           encoding = fontEncoding;
   47   
   48           //first set up the base encoding
   49           //The previious value WinAnsiEncoding() has been changed to StandardEnding
   50           //see p 389 of the PDF 1.5 ref?rence table 5.11 entries in a dictionary encoding
   51           //"If this entry is absent, the Differences entry describes differences from an implicit
   52           //base encoding. For a font program that is embedded in the PDF file, the
   53           //implicit base encoding is the font program?s built-in encoding, as described
   54           //above and further elaborated in the sections on specific font types below. Otherwise,
   55           //for a nonsymbolic font, it is StandardEncoding, and for a symbolic font, it
   56           //is the font?s built-in encoding."
   57   
   58           //so the default base encoding is standardEncoding
   59           Encoding baseEncoding = new StandardEncoding();
   60           COSName baseEncodingName = (COSName)encoding.getDictionaryObject( COSName.BASE_ENCODING );
   61   
   62           if( baseEncodingName != null )
   63           {
   64               EncodingManager manager = new EncodingManager();
   65               baseEncoding = manager.getEncoding( baseEncodingName );
   66           }
   67           nameToCode.putAll( baseEncoding.nameToCode );
   68           codeToName.putAll( baseEncoding.codeToName );
   69   
   70   
   71           //now replace with the differences.
   72           COSArray differences = (COSArray)encoding.getDictionaryObject( COSName.DIFFERENCES );
   73           int currentIndex = -1;
   74           for( int i=0; differences != null && i<differences.size(); i++ )
   75           {
   76               COSBase next = differences.getObject( i );
   77               if( next instanceof COSNumber )
   78               {
   79                   currentIndex = ((COSNumber)next).intValue();
   80               }
   81               else if( next instanceof COSName )
   82               {
   83                   COSName name = (COSName)next;
   84                   addCharacterEncoding( currentIndex++, name );
   85               }
   86           }
   87       }
   88   
   89       /**
   90        * Convert this standard java object to a COS object.
   91        *
   92        * @return The cos object that matches this Java object.
   93        */
   94       public COSBase getCOSObject()
   95       {
   96           return encoding;
   97       }
   98   }