package org.apache.maven.index.packer;

 /*

  * 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.

  */

 import java.io.ByteArrayInputStream;

 import java.io.File;

 import java.io.FileInputStream;

 import java.io.FileNotFoundException;

 import java.io.IOException;

 import java.io.InputStream;

 import java.io.UnsupportedEncodingException;

 import java.security.MessageDigest;

 import java.security.NoSuchAlgorithmException;

 import org.codehaus.plexus.util.IOUtil;

 /**

  * A util class to calculate various digests on Strings. Useful for some simple password management.

  * 

  * @author cstamas

  */

 public class DigesterUtils

 {

     /**

      * Calculates a digest for a String user the requested algorithm.

      * 

      * @param alg

      * @param content

      * @return

      * @throws NoSuchAlgorithmException

      */

     private static String getDigest( String alg, InputStream is )

         throws NoSuchAlgorithmException

     {

         String result = null;

         try

         {

             try

             {

                 byte[] buffer = new byte[1024];

                 MessageDigest md = MessageDigest.getInstance( alg );

                 int numRead;

                 do

                 {

                     numRead = is.read( buffer );

                     if ( numRead > 0 )

                     {

                         md.update( buffer, 0, numRead );

                     }

                 }

                 while ( numRead != -1 );

                 result = new String( encodeHex( md.digest() ) );

             }

             finally

             {

                 is.close();

             }

         }

         catch ( IOException e )

         {

             // hrm

             result = null;

         }

         return result;

     }

     // SHA1

     /**

      * Calculates a SHA1 digest for a string.

      * 

      * @param content

      * @return

      */

     public static String getSha1Digest( String content )

     {

         try

         {

             InputStream fis = new ByteArrayInputStream( content.getBytes( "UTF-8" ) );

             return getDigest( "SHA1", fis );

         }

         catch ( NoSuchAlgorithmException e )

         {

             // will not happen

             return null;

         }

         catch ( UnsupportedEncodingException e )

         {

             // will not happen

             return null;

         }

     }

     /**

      * Calculates a SHA1 digest for a stream.

      * 

      * @param content

      * @return

      */

     public static String getSha1Digest( InputStream is )

     {

         try

         {

             return getDigest( "SHA1", is );

         }

         catch ( NoSuchAlgorithmException e )

         {

             // will not happen

             return null;

         }

     }

     /**

      * Calculates a SHA1 digest for a file.

      * 

      * @param content

      * @return

      */

     public static String getSha1Digest( File file )

     {

         FileInputStream fis = null;

         try

         {

             fis = new FileInputStream( file );

             return getDigest( "SHA1", fis );

         }

         catch ( NoSuchAlgorithmException e )

         {

             // will not happen

             return null;

         }

         catch ( FileNotFoundException e )

         {

             // will not happen

             return null;

         }

         finally

         {

             IOUtil.close( fis );

         }

     }

     // MD5

     /**

      * Calculates a SHA1 digest for a string.

      * 

      * @param content

      * @return

      */

     public static String getMd5Digest( String content )

     {

         try

         {

             InputStream fis = new ByteArrayInputStream( content.getBytes( "UTF-8" ) );

             return getDigest( "MD5", fis );

         }

         catch ( NoSuchAlgorithmException e )

         {

             // will not happen

             return null;

         }

         catch ( UnsupportedEncodingException e )

         {

             // will not happen

             return null;

         }

     }

     /**

      * Calculates a SHA1 digest for a stream.

      * 

      * @param content

      * @return

      */

     public static String getMd5Digest( InputStream is )

     {

         try

         {

             return getDigest( "MD5", is );

         }

         catch ( NoSuchAlgorithmException e )

         {

             // will not happen

             return null;

         }

     }

     /**

      * Calculates a SHA1 digest for a file.

      * 

      * @param content

      * @return

      */

     public static String getMd5Digest( File file )

     {

         FileInputStream fis = null;

         try

         {

             fis = new FileInputStream( file );

             return getDigest( "MD5", fis );

         }

         catch ( NoSuchAlgorithmException e )

         {

             // will not happen

             return null;

         }

         catch ( FileNotFoundException e )

         {

             // will not happen

             return null;

         }

         finally

         {

             IOUtil.close( fis );

         }

     }

     // --

     private static final char[] DIGITS = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e',

         'f' };

     /**

      * Blatantly copied from commons-codec version 1.3

      * 

      * @param data

      * @return

      */

     public static char[] encodeHex( byte[] data )

     {

         int l = data.length;

         char[] out = new char[l << 1];

         // two characters form the hex value.

         for ( int i = 0, j = 0; i < l; i++ )

         {

             out[j++] = DIGITS[( 0xF0 & data[i] ) >>> 4];

             out[j++] = DIGITS[0x0F & data[i]];

         }

         return out;

     }

 }