/*
    * The contents of this file are subject to the terms of the Common Development and
    * Distribution License (the License). You may not use this file except in compliance with the
    * License.
    *
    * You can obtain a copy of the License at legal/CDDLv1.0.txt. See the License for the
    * specific language governing permission and limitations under the License.
    *
    * When distributing Covered Software, include this CDDL Header Notice in each file and include
   * the License file at legal/CDDLv1.0.txt. If applicable, add the following below the CDDL
   * Header, with the fields enclosed by brackets [] replaced by your own identifying
   * information: "Portions copyright [year] [name of copyright owner]".
   *
   * Copyright 2013-2015 ForgeRock AS.
   */
  
  package org.forgerock.json.jose.jwe.handlers.compression;
  
  import java.io.ByteArrayInputStream;
  import java.io.ByteArrayOutputStream;
  import java.io.IOException;
  import java.util.zip.Deflater;
  import java.util.zip.DeflaterOutputStream;
  import java.util.zip.Inflater;
  import java.util.zip.InflaterInputStream;
  
  import org.forgerock.json.jose.exceptions.JweCompressionException;
  
  /**
   * An implementation of the CompressionHandler for DEFLATE Compressed Data Format Specification.
   * <p>
   * @see <a href="http://tools.ietf.org/html/rfc1951">DEFLATE Compressed Data Format Specification version 1.3</a>
   *
   */
  public class DeflateCompressionHandler implements CompressionHandler {
  
      /**
       * {@inheritDoc}
       */
      @Override
      public byte[] compress(byte[] bytes) {
          ByteArrayOutputStream byteOutputStream = new ByteArrayOutputStream();
          try (DeflaterOutputStream deflaterOutputStream = new DeflaterOutputStream(byteOutputStream,
                       new Deflater(Deflater.DEFLATED, true))) {
              deflaterOutputStream.write(bytes);
          } catch (IOException e) {
              throw new JweCompressionException("Failed to apply compression algorithm.", e);
          }
  
          return byteOutputStream.toByteArray();
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public byte[] decompress(byte[] bytes) {
          ByteArrayOutputStream byteOutputStream = new ByteArrayOutputStream();
          try (InflaterInputStream inflaterInputStream = new InflaterInputStream(new ByteArrayInputStream(bytes),
                  new Inflater(true));
               ByteArrayOutputStream out = byteOutputStream) {
              byte[] buffer = new byte[1024];
              int l;
              while ((l = inflaterInputStream.read(buffer)) > 0) {
                  out.write(buffer, 0, l);
              }
          } catch (IOException e) {
              throw new JweCompressionException("Failed to apply de-compression algorithm.", e);
          }
  
          return byteOutputStream.toByteArray();
      }
  }