source: trunk/docx4j/src/main/java/org/docx4j/openpackaging/parts/WordprocessingML/ObfuscatedFontPart.java @ 1234

/*
 *  Copyright 2007-2008, Plutext Pty Ltd.
 *   
 *  This file is part of docx4j.

    docx4j is licensed 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.docx4j.openpackaging.parts.WordprocessingML;

import org.apache.log4j.Logger;
import org.docx4j.fonts.fop.fonts.CustomFont;
import org.docx4j.fonts.fop.fonts.EncodingMode;
import org.docx4j.fonts.fop.fonts.FontLoader;
import org.docx4j.fonts.fop.fonts.FontResolver;
import org.docx4j.fonts.fop.fonts.FontSetup;
import org.docx4j.fonts.fop.fonts.autodetect.FontFileFinder;
import org.docx4j.fonts.fop.fonts.autodetect.FontInfoFinder;
import org.docx4j.openpackaging.exceptions.InvalidFormatException;
import org.docx4j.openpackaging.parts.PartName;
import org.docx4j.openpackaging.parts.relationships.Namespaces;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.ByteArrayOutputStream;
import java.net.MalformedURLException;

public class ObfuscatedFontPart extends BinaryPart {

        private static Logger log = Logger.getLogger(ObfuscatedFontPart.class);         
        
    /** docx4j's user directory name */
    private static final String DOCX4J_USER_DIR = ".docx4all"; 
        // docx4all already creates a dir; no point creating a second 

    /** font cache file path */
    private static final String TEMPORARY_FONT_DIR = "temporary embedded fonts";
        
    private static File tmpFontDir = null; 
    
    static {
        File userHome = getUserHome();
        if (userHome != null) {
            File docx4jUserDir = new File(userHome, DOCX4J_USER_DIR);
            docx4jUserDir.mkdir();
            tmpFontDir = new File(docx4jUserDir, TEMPORARY_FONT_DIR);
            tmpFontDir.mkdir();
        }       
    }
    
    public static String getTemporaryEmbeddedFontsDir() {
        try {
                        return tmpFontDir.getCanonicalPath();
                } catch (IOException e) {
                        e.printStackTrace();
                        return null;
                }
    }
    
    private static File getUserHome() {
        String s = System.getProperty("user.home");
        if (s != null) {
            File userDir = new File(s);
            if (userDir.exists()) {
                return userDir;
            }
        }
        return null;
    }

        public ObfuscatedFontPart(PartName partName) throws InvalidFormatException {
                super(partName);
                init();                         
        }
        
        public void init() {
                // Used if this Part is added to [Content_Types].xml 
                setContentType(new  org.docx4j.openpackaging.contenttype.ContentType( 
                                org.docx4j.openpackaging.contenttype.ContentTypes.OFFICEDOCUMENT_FONT));

                // Used when this Part is added to a rels
                // TODO
                //setRelationshipType(Namespaces.);
        }
        
        
        /**
         * deObfuscate this font, and save it using fontName
         * 
         * @param fontName - the name to save the font as. We
         * could read the font name from the deObfuscated data,
         * but FontLoader can't readily load from a byte array. 
         * @param fontKey
         */
        public void deObfuscate(String fontName, String fontKey ) {
                
                byte[] fontData = null;
                                
        bb.clear();
        fontData = new byte[bb.capacity()];
        bb.get(fontData, 0, fontData.length);
                
                log.debug("bytes: " + fontData.length);
                
                log.info("deObfuscating with fontkey: " + fontKey);                     
                // INPUT: {1DF903E3-2F14-4575-8028-881FEBABF2AB}

                // See http://openiso.org/Ecma/376/Part4/2.8.1
                // for how to do this.
                
                
                // First, strip {,}
                String tmpString = fontKey.substring(1, fontKey.length()-1);
                log.debug(tmpString);
                
                // Now strip -
                String guidString = tmpString.replace(target, replacement);
                log.debug(guidString);

                
                // Make the font key into a byte array
                byte[] guidByteArray = new byte[16];
                for (int i = 0; i < guidByteArray.length; i++) {
                        guidByteArray[i] = fromHexString(guidString.substring(i * 2,
                                        (i * 2) + 2));
                }
                
                // XOR the reverse of the guidByteArray with 
                // the first and second 16 bytes 
                for (int j = 0; j < 2; j++) {
                        for (int i = 0; i < 16; i++) {
                                fontData[(j * 16) + i] ^= guidByteArray[15 - i];  // Reverse happens here
                        }
                }
                
                // Save the result
                java.io.File f = new File(tmpFontDir, fontName +".ttf"); 
                String path = null; 
                
                java.io.FileOutputStream fos = null; 
                try {
                        path = f.getCanonicalPath();
                        fos = new java.io.FileOutputStream(f);
                        fos.write(fontData);
                        log.debug("wrote: " + fontData.length);
                        fos.close();
                } catch (IOException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                } 
                
                log.info("Done!");
                
                // Save to "Temporary Font Files" directory.
        FontResolver fontResolver = FontSetup.createMinimalFontResolver();

                if (log.isDebugEnabled()) {
                CustomFont customFont = null;
                try {
                        log.debug("Loading from: " + path);
                        String subFontName = null; // TODO set this if its a TTC
                        boolean embedded = true;   
                        boolean useKerning = true;
                    customFont = FontLoader.loadFont("file:" + path, 
                                subFontName, embedded, EncodingMode.AUTO, useKerning, fontResolver);
                } catch (Exception e) {
                                e.printStackTrace();
                }
                if (customFont!=null) {
                        log.info("Successfully reloaded " + customFont.getFontName());
                        if (customFont.isEmbeddable()) {
                                log.debug("confirmed embeddable");
                        } else {
                                // Sanity check
                                log.error("this embedded font claims it is not embeddable!");                   
                        }
                }
                }
                
                // Add this font to our known physical fonts  
        try {
                        org.docx4j.fonts.PhysicalFonts.addPhysicalFont(new java.net.URL("file:" + path) );
                        
                        // This needs to be done before populateFontMappings, 
                        // otherwise this font will be ignored, and references
                        // to it mapped to some substitute font!
                        
                } catch (MalformedURLException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                }
                
        }
        
        
        public static byte fromHexString( String hexStr ){
        byte firstNibble  = Byte.parseByte(hexStr.substring(0,1),16); 
        byte secondNibble = Byte.parseByte(hexStr.substring(1,2),16);
        int finalByte = (secondNibble) | (firstNibble << 4 ); 
        return (byte) finalByte;
        }
        
        
        static java.lang.CharSequence target = (new String("-")).subSequence(0, 1);
    static java.lang.CharSequence replacement = (new String("")).subSequence(0, 0);
        
        
        
}