/*
    * This file is part of ***  M y C o R e  ***
    * See http://www.mycore.de/ for details.
    *
    * MyCoRe is free software: you can redistribute it and/or modify
    * it under the terms of the GNU General Public License as published by
    * the Free Software Foundation, either version 3 of the License, or
    * (at your option) any later version.
    *
   * MyCoRe is distributed in the hope that it will be useful,
   * but 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.
   *
   * You should have received a copy of the GNU General Public License
   * along with MyCoRe.  If not, see <http://www.gnu.org/licenses/>.
   */
  
  package org.mycore.common.content;
  
  import java.io.ByteArrayInputStream;
  import java.io.InputStream;
  import java.security.MessageDigest;
  import java.util.Arrays;
  
  import org.mycore.common.content.streams.MCRMD5InputStream;
  
  /**
   * Reads MCRContent from a byte[] array.
   * 
   * @author Frank L\u00FCtzenkichen
   */
  public class MCRByteContent extends MCRContent {
  
      private byte[] bytes;
  
      private int offset;
  
      private int length;
  
      private long lastModified;
  
      public MCRByteContent(byte[] bytes) {
          this(bytes, 0, bytes.length);
      }
  
      public MCRByteContent(byte[] bytes, int offset, int length) {
          this(bytes, offset, length, System.currentTimeMillis());
      }
  
      public MCRByteContent(byte[] bytes, long lastModified) {
          this(bytes, 0, bytes.length, lastModified);
      }
  
      public MCRByteContent(byte[] bytes, int offset, int length, long lastModified) {
          this.bytes = bytes;
          this.offset = offset;
          this.length = length;
          this.lastModified = lastModified;
      }
  
      @Override
      public void setSystemId(String systemId) {
          this.systemId = systemId;
      }
  
      @Override
      public InputStream getInputStream() {
          return new ByteArrayInputStream(bytes, offset, length);
      }
  
      @Override
      public byte[] asByteArray() {
          if (offset == 0 && length == 0) {
              return bytes;
          }
          synchronized (this) {
              if (offset == 0 && length == bytes.length) {
                  return bytes;
              }
              bytes = Arrays.copyOfRange(bytes, offset, offset + length);
              offset = 0;
              length = bytes.length;
          }
          return bytes;
      }
  
      @Override
      public long length() {
          return length;
      }
  
      @Override
      public long lastModified() {
          return lastModified;
      }
  
      @Override
      public String getETag() {
         MessageDigest md5Digest = MCRMD5InputStream.buildMD5Digest();
         md5Digest.update(bytes, offset, length);
         byte[] digest = md5Digest.digest();
         String md5String = MCRMD5InputStream.getMD5String(digest);
         return '"' + md5String + '"';
     }
 }