/* CipherFactory.java -- 
   Copyright (C) 2001, 2002, 2003, 2006 Free Software Foundation, Inc.

This file is a part of GNU Classpath.

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it under the terms of the GNU General Public License as published by
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General Public License for more details.

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permission to link this library with independent modules to produce an
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package gnu.javax.crypto.cipher;

import gnu.java.security.Registry;

import java.util.Collections;
import java.util.HashSet;
import java.util.Set;

/**
 * A <i>Factory</i> to instantiate symmetric block cipher instances.
 */
public class CipherFactory
    implements Registry
{
  /** Trivial constructor to enforce Singleton pattern. */
  private CipherFactory()
  {
    super();
  }

  /**
   * Returns an instance of a block cipher given its name.
   * 
   * @param name the case-insensitive name of the symmetric-key block cipher
   *          algorithm.
   * @return an instance of the designated cipher algorithm, or
   *         <code>null</code> if none is found.
   * @exception InternalError if the implementation does not pass its self-test.
   */
  public static final IBlockCipher getInstance(String name)
  {
    if (name == null)
      return null;
    name = name.trim();
    IBlockCipher result = null;
    if (name.equalsIgnoreCase(ANUBIS_CIPHER))
      result = new Anubis();
    else if (name.equalsIgnoreCase(BLOWFISH_CIPHER))
      result = new Blowfish();
    else if (name.equalsIgnoreCase(DES_CIPHER))
      result = new DES();
    else if (name.equalsIgnoreCase(KHAZAD_CIPHER))
      result = new Khazad();
    else if (name.equalsIgnoreCase(RIJNDAEL_CIPHER)
             || name.equalsIgnoreCase(AES_CIPHER))
      result = new Rijndael();
    else if (name.equalsIgnoreCase(SERPENT_CIPHER))
      result = new Serpent();
    else if (name.equalsIgnoreCase(SQUARE_CIPHER))
      result = new Square();
    else if (name.equalsIgnoreCase(TRIPLEDES_CIPHER)
             || name.equalsIgnoreCase(DESEDE_CIPHER))
      result = new TripleDES();
    else if (name.equalsIgnoreCase(TWOFISH_CIPHER))
      result = new Twofish();
    else if (name.equalsIgnoreCase(CAST5_CIPHER)
             || (name.equalsIgnoreCase(CAST128_CIPHER)
                 || (name.equalsIgnoreCase(CAST_128_CIPHER))))
      result = new Cast5();
    else if (name.equalsIgnoreCase(NULL_CIPHER))
      result = new NullCipher();

    if (result != null && ! result.selfTest())
      throw new InternalError(result.name());

    return result;
  }

  /**
   * Returns a {@link Set} of symmetric key block cipher implementation names
   * supported by this <i>Factory</i>.
   * 
   * @return a {@link Set} of block cipher names (Strings).
   */
  public static final Set getNames()
  {
    HashSet hs = new HashSet();
    hs.add(ANUBIS_CIPHER);
    hs.add(BLOWFISH_CIPHER);
    hs.add(DES_CIPHER);
    hs.add(KHAZAD_CIPHER);
    hs.add(RIJNDAEL_CIPHER);
    hs.add(SERPENT_CIPHER);
    hs.add(SQUARE_CIPHER);
    hs.add(TRIPLEDES_CIPHER);
    hs.add(TWOFISH_CIPHER);
    hs.add(CAST5_CIPHER);
    hs.add(NULL_CIPHER);
    return Collections.unmodifiableSet(hs);
  }
}