/**
 * 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.hadoop.hive.ql.io.orc.encoded;

import java.io.IOException;
import java.nio.ByteBuffer;

import org.apache.hadoop.hive.common.DiskRangeInfo;
import org.apache.hadoop.hive.common.io.DiskRange;
import org.apache.hadoop.hive.common.io.encoded.EncodedColumnBatch.ColumnStreamData;
import org.apache.hadoop.hive.common.io.encoded.MemoryBuffer;
import org.apache.orc.impl.SettableUncompressedStream;
import org.apache.orc.impl.BufferChunk;

import com.google.common.collect.Lists;

/**
 * Stream utility.
 */
public class StreamUtils {

  /**
   * Create SettableUncompressedStream from stream buffer.
   *
   * @param streamName - stream name
   * @param streamBuffer - stream buffer
   * @return - SettableUncompressedStream
   * @throws IOException
   */
  public static SettableUncompressedStream createSettableUncompressedStream(String streamName,
      ColumnStreamData streamBuffer) throws IOException {
    if (streamBuffer == null) {
      return null;
    }

    if (streamBuffer.getCacheBuffers() != null) {
      DiskRangeInfo diskRangeInfo = createDiskRangeInfo(streamBuffer);
      return new SettableUncompressedStream(streamName, diskRangeInfo.getDiskRanges(),
          diskRangeInfo.getTotalLength());
    } else {
      return new SettableUncompressedStream(streamName, Lists.<DiskRange>newArrayList(), 0);
    }
  }

  /**
   * Converts stream buffers to disk ranges.
   * @param streamBuffer - stream buffer
   * @return - total length of disk ranges
   */
  public static DiskRangeInfo createDiskRangeInfo(ColumnStreamData streamBuffer) {
    DiskRangeInfo diskRangeInfo = new DiskRangeInfo(streamBuffer.getIndexBaseOffset());
    long offset = streamBuffer.getIndexBaseOffset(); // See ctor comment.
    // TODO: we should get rid of this
    for (MemoryBuffer memoryBuffer : streamBuffer.getCacheBuffers()) {
      ByteBuffer buffer = memoryBuffer.getByteBufferDup();
      diskRangeInfo.addDiskRange(new BufferChunk(buffer, offset));
      offset += buffer.remaining();
    }
    return diskRangeInfo;
  }
}