exec/java-exec/src/main/java/org/apache/drill/exec/store/dfs/SeekableByteArrayInputStream.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  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.
 */

package org.apache.drill.exec.store.dfs;

import org.apache.hadoop.fs.PositionedReadable;
import org.apache.hadoop.fs.Seekable;

import java.io.ByteArrayInputStream;
import java.io.IOException;

public class SeekableByteArrayInputStream extends ByteArrayInputStream implements Seekable, PositionedReadable {

  public SeekableByteArrayInputStream(byte[] buf)
  {
    super(buf);
  }
  @Override
  public long getPos() throws IOException {
    return pos;
  }

  @Override
  public void seek(long pos) throws IOException {
    if (mark != 0) {
      throw new IllegalStateException();
    }

    reset();
    long skipped = skip(pos);

    if (skipped != pos) {
      throw new IOException();
    }
  }

  @Override
  public boolean seekToNewSource(long targetPos) throws IOException {
    return false;
  }

  @Override
  public int read(long position, byte[] buffer, int offset, int length) throws IOException {

    if (position >= buf.length) {
      throw new IllegalArgumentException();
    }
    if (position + length > buf.length) {
      throw new IllegalArgumentException();
    }
    if (length > buffer.length) {
      throw new IllegalArgumentException();
    }

    System.arraycopy(buf, (int) position, buffer, offset, length);
    return length;
  }

  @Override
  public void readFully(long position, byte[] buffer) throws IOException {
    read(position, buffer, 0, buffer.length);

  }

  @Override
  public void readFully(long position, byte[] buffer, int offset, int length) throws IOException {
    read(position, buffer, offset, length);
  }
}