/*
 * Copyright 2014 Amazon.com, Inc. or its affiliates. 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.
 * A copy of the License is located at
 *
 *  http://aws.amazon.com/apache2.0
 *
 * or in the "license" file accompanying this file. This file 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.amazonaws.services.dynamodbv2.datamodeling.internal;

import java.io.InputStream;
import java.nio.ByteBuffer;

/** @author Greg Rubin */
public class ByteBufferInputStream extends InputStream {
  private final ByteBuffer buffer;

  public ByteBufferInputStream(ByteBuffer buffer) {
    this.buffer = buffer;
  }

  @Override
  public int read() {
    if (buffer.hasRemaining()) {
      int tmp = buffer.get();
      if (tmp < 0) {
        tmp += 256;
      }
      return tmp;
    } else {
      return -1;
    }
  }

  @Override
  public int read(byte[] b, int off, int len) {
    if (available() < len) {
      len = available();
    }
    buffer.get(b, off, len);
    return len;
  }

  @Override
  public int available() {
    return buffer.remaining();
  }
}