/*

  * Copyright (c) 2011 ICM Uniwersytet Warszawski All rights reserved.

  * See LICENCE file for licensing information.

  */

 package eu.emi.security.authn.x509.helpers;

 import java.io.IOException;

 import java.io.Reader;

 import java.util.ArrayList;

 import java.util.List;

 import java.util.regex.Matcher;

 import java.util.regex.Pattern;

 import org.bouncycastle.openssl.PEMParser;

 import org.bouncycastle.util.encoders.Base64;

 import org.bouncycastle.util.io.pem.PemHeader;

 import org.bouncycastle.util.io.pem.PemObject;

 /**

  * Extends BC's {@link PEMReader} class so it can read correctly also 

  * PEM files with a garbage at the beginning 

  * and minor syntax violations which occur more then often in the wild. 

  *

  * TODO - probably we can remove this class - BC seems to be fixed.

  *

  * @author K. Benedyczak

  */

 public class FlexiblePEMReader extends PEMParser

 {

         /**

          * Creates a new {@link FlexiblePEMReader} object. 

          * @param reader input source

          */

         public FlexiblePEMReader(Reader reader)

         {

                 super(reader);

         }

         /**

          * Generate BC's PemObject

          * @return the parsed PEM object

          * @throws IOException

          */

         @Override

         public PemObject readPemObject() throws IOException

         {

                 Pattern starter = Pattern.compile("^---[-]+BEGIN [^-]+---[-]+$");

                 Pattern end = Pattern.compile("^---[-]+END [^-]+---[-]+$");

                 String line;

                 boolean startFound = false;

                 while ((line=readLine()) != null)

                 {

                         Matcher m = starter.matcher(line);

                         if (m.find())

                         {

                                 startFound = true;

                                 break;

                         }

                 }

                 if (!startFound)

                         return null;

                 int pos = line.indexOf("BEGIN ") + 6;

                 int endPos = line.indexOf('-', pos);

                 String type = line.substring(pos, endPos);

                 boolean endFound = false;

                 StringBuilder sb = new StringBuilder();

                 List<PemHeader> headers = new ArrayList<PemHeader>();

                 while ((line=readLine()) != null)

                 {

                         Matcher m = end.matcher(line);

                         if (m.find())

                                 throw new IOException("The supplied data is not in PEM format, end line found before getting any contents.");

                         if (line.indexOf(":") >= 0)

                         {

                                 int index = line.indexOf(':');

                                 String hdr = line.substring(0, index);

                                 String value = line.substring(index + 1).trim();

                                 headers.add(new PemHeader(hdr, value));

                         } else 

                         {

                                 sb.append(line.trim());

                                 break;

                         }

                 }

                 while ((line=readLine()) != null)

                 {

                         Matcher m = end.matcher(line);

                         if (m.find())

                         {

                                 endFound = true;

                                 break;

                         } else 

                                 sb.append(line.trim());

                 }

                 if (!endFound)

                         throw new IOException("The supplied data is not in PEM format, no ending line found.");

                 return new PemObject(type, headers, Base64.decode(sb.toString()));

         }

 }