/* SignatureAdapter.java -- 
   Copyright 2001, 2002, 2006 Free Software Foundation, Inc.

This file is a part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

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USA

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
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permission to link this library with independent modules to produce an
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package gnu.java.security.jce.sig;

import gnu.java.security.sig.BaseSignature;
import gnu.java.security.sig.ISignature;
import gnu.java.security.sig.ISignatureCodec;
import gnu.java.security.sig.SignatureFactory;

import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.InvalidParameterException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;
import java.security.SignatureException;
import java.security.SignatureSpi;
import java.security.spec.AlgorithmParameterSpec;
import java.util.HashMap;
import java.util.logging.Logger;

/**
 * The implementation of a generic {@link java.security.Signature} adapter class
 * to wrap gnu.crypto signature instances.<p>
 *
 * This class defines the <i>Service Provider Interface</i> (<b>SPI</b>) for the
 * {@link java.security.Signature} class, which provides the functionality of a
 * digital signature algorithm. Digital signatures are used for authentication
 * and integrity assurance of digital data.<p>
 *
 * All the abstract methods in the {@link java.security.SignatureSpi} class are
 * implemented by this class and all its sub-classes.<p>
 *
 * All the implementations which subclass this object, and which are serviced by
 * the GNU Crypto provider implement the {@link java.lang.Cloneable} interface.<p>
 */
class SignatureAdapter extends SignatureSpi implements Cloneable
{
  private static final Logger log = Logger.getLogger(SignatureAdapter.class.getName());

  // Constants and variables
  // -------------------------------------------------------------------------

  /** Our underlying signature instance. */
  private ISignature adaptee;

  /** Our underlying signature encoder/decoder engine. */
  private ISignatureCodec codec;

  // Constructor(s)
  // -------------------------------------------------------------------------

  /**
   * Trivial protected constructor.<p>
   *
   * @param sigName the canonical name of the signature scheme.
   * @param codec the signature codec engine to use with this scheme.
   */
  protected SignatureAdapter(String sigName, ISignatureCodec codec)
  {
    this(SignatureFactory.getInstance(sigName), codec);
  }

  /**
   * Private constructor for cloning purposes.<p>
   *
   * @param adaptee a clone of the underlying signature scheme instance.
   * @param codec the signature codec engine to use with this scheme.
   */
  private SignatureAdapter(ISignature adaptee, ISignatureCodec codec)
  {
    super();

    this.adaptee = adaptee;
    this.codec = codec;
  }

  // Class methods
  // -------------------------------------------------------------------------

  // java.security.SignatureSpi interface implementation
  // -------------------------------------------------------------------------

  public Object clone()
  {
    return new SignatureAdapter((ISignature) adaptee.clone(), codec);
  }

  public void engineInitVerify(PublicKey publicKey) throws InvalidKeyException
  {
    HashMap attributes = new HashMap();
    attributes.put(BaseSignature.VERIFIER_KEY, publicKey);
    try
      {
        adaptee.setupVerify(attributes);
      }
    catch (IllegalArgumentException x)
      {
        throw new InvalidKeyException(String.valueOf(x));
      }
  }

  public void engineInitSign(PrivateKey privateKey) throws InvalidKeyException
  {
    HashMap attributes = new HashMap();
    attributes.put(BaseSignature.SIGNER_KEY, privateKey);
    try
      {
        adaptee.setupSign(attributes);
      }
    catch (IllegalArgumentException x)
      {
        throw new InvalidKeyException(String.valueOf(x));
      }
  }

  public void engineInitSign(PrivateKey privateKey, SecureRandom random)
      throws InvalidKeyException
  {
    HashMap attributes = new HashMap();
    attributes.put(BaseSignature.SIGNER_KEY, privateKey);
    attributes.put(BaseSignature.SOURCE_OF_RANDOMNESS, random);
    try
      {
        adaptee.setupSign(attributes);
      }
    catch (IllegalArgumentException x)
      {
        throw new InvalidKeyException(String.valueOf(x));
      }
  }

  public void engineUpdate(byte b) throws SignatureException
  {
    try
      {
        adaptee.update(b);
      }
    catch (IllegalStateException x)
      {
        throw new SignatureException(String.valueOf(x));
      }
  }

  public void engineUpdate(byte[] b, int off, int len)
      throws SignatureException
  {
    try
      {
        adaptee.update(b, off, len);
      }
    catch (IllegalStateException x)
      {
        throw new SignatureException(String.valueOf(x));
      }
  }

  public byte[] engineSign() throws SignatureException
  {
    Object signature = null;
    try
      {
        signature = adaptee.sign();
      }
    catch (IllegalStateException x)
      {
        throw new SignatureException(String.valueOf(x));
      }

    byte[] result = codec.encodeSignature(signature);
    return result;
  }

  public int engineSign(byte[] outbuf, int offset, int len)
      throws SignatureException
  {
    byte[] signature = this.engineSign();
    int result = signature.length;
    if (result > len)
      {
        throw new SignatureException("len");
      }

    System.arraycopy(signature, 0, outbuf, offset, result);
    return result;
  }

  public boolean engineVerify(byte[] sigBytes) throws SignatureException
  {
    log.entering("SignatureAdapter", "engineVerify");

    Object signature = codec.decodeSignature(sigBytes);
    boolean result = false;
    try
      {
        result = adaptee.verify(signature);
      }
    catch (IllegalStateException x)
      {
        throw new SignatureException(String.valueOf(x));
      }

    log.exiting("SignatureAdapter", "engineVerify", new Boolean(result));
    return result;
  }

  // Deprecated. Replaced by engineSetParameter.
  public void engineSetParameter(String param, Object value)
      throws InvalidParameterException
  {
    throw new InvalidParameterException("deprecated");
  }

  public void engineSetParameter(AlgorithmParameterSpec params)
      throws InvalidAlgorithmParameterException
  {
  }

  // Deprecated
  public Object engineGetParameter(String param)
      throws InvalidParameterException
  {
    throw new InvalidParameterException("deprecated");
  }
}
