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'rapiddweller Common' is an open source Java library forked from Databene Commons by Volker Bergmann. It provides extensions to the Java core library by utility classes, abstract concepts and concrete implementations.

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/*
 * Copyright (C) 2004-2015 Volker Bergmann ([email protected]).
 * All rights reserved.
 *
 * Licensed 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.
 */

package com.rapiddweller.common.io;

import java.io.IOException;
import java.io.PushbackReader;
import java.io.Reader;
import java.nio.CharBuffer;

/**
 * Special {@link PushbackReader} implementation which provides the current cursor offset.
 * Created: 19.03.2013 21:13:02
 *
 * @author Volker Bergmann
 * @since 0.5.23
 */
public class OffsetPushbackReader extends PushbackReader {

  /**
   * The Offset.
   */
  int offset;

  /**
   * Instantiates a new Offset pushback reader.
   *
   * @param in the in
   */
  public OffsetPushbackReader(Reader in) {
    this(in, 1);
  }

  /**
   * Instantiates a new Offset pushback reader.
   *
   * @param in                 the in
   * @param pushBackBufferSize the push back buffer size
   */
  public OffsetPushbackReader(Reader in, int pushBackBufferSize) {
    super(in, pushBackBufferSize);
    this.offset = 0;
  }

  @Override
  public int read() throws IOException {
    offset++;
    return super.read();
  }

  @Override
  public int read(char[] charBuffer) throws IOException {
    int count = super.read(charBuffer);
    offset += count;
    return count;
  }

  @Override
  public int read(CharBuffer charVuffer) throws IOException {
    int count = super.read(charVuffer);
    offset += count;
    return count;
  }

  @Override
  public void unread(int c) throws IOException {
    offset--;
    super.unread(c);
  }

  @Override
  public void unread(char[] charBuffer) throws IOException {
    offset -= charBuffer.length;
    super.unread(charBuffer);
  }

  @Override
  public void unread(char[] charBuffer, int off, int len) throws IOException {
    offset -= len;
    super.unread(charBuffer, off, len);
  }

  /**
   * Gets offset.
   *
   * @return the offset
   */
  public int getOffset() {
    return offset;
  }

}