org.apache.abdera.i18n.text.io.PeekAheadInputStream Maven / Gradle / Ivy

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package org.apache.abdera.i18n.text.io;
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  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.  For additional information regarding
 * copyright in this work, please see the NOTICE file in the top level
 * directory of this distribution.
 */

import java.io.IOException;
import java.io.InputStream;

/**
 * A version of RewindableInputStream that provides methods for peeking ahead 
 * in the stream (equivalent to read() followed by an appropriate unread() 
 */
public class PeekAheadInputStream 
  extends RewindableInputStream {
  
  public PeekAheadInputStream(
    InputStream in) {
      super(in);
  }
  
  public PeekAheadInputStream(
    InputStream in, 
    int initialSize) {
      super(in,initialSize);
  }

  /**
   * Peek the next byte in the stream
   */
  public int peek() 
    throws IOException {
      int m = read();
      unread(m);
      return m;
  }
  
  /**
   * Peek the next bytes in the stream. Returns the number of bytes peeked.
   * Will return -1 if the end of the stream is reached
   */
  public int peek(
    byte[] buf) 
      throws IOException {
    return peek(buf, 0, buf.length);
  }

  /**
   * Peek the next bytes in the stream. Returns the number of bytes peeked.
   * Will return -1 if the end of the stream is reached
   */
  public int peek(
    byte[] buf, 
    int off, 
    int len) 
      throws IOException {
    int r = read(buf, off, len);
    unread(buf,off,len);
    return r;
  }

}