/* 
 * 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 parquet.hadoop.codec;

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

import org.apache.hadoop.conf.Configurable;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.compress.CompressionCodec;
import org.apache.hadoop.io.compress.CompressionInputStream;
import org.apache.hadoop.io.compress.CompressionOutputStream;
import org.apache.hadoop.io.compress.Compressor;
import org.apache.hadoop.io.compress.Decompressor;

/**
 * Snappy compression codec for Parquet.  We do not use the default hadoop
 * one since that codec adds a blocking structure around the base snappy compression
 * algorithm.  This is useful for hadoop to minimize the size of compression blocks
 * for their file formats (e.g. SequenceFile) but is undesirable for Parquet since
 * we already have the data page which provides that.
 */
public class SnappyCodec implements Configurable, CompressionCodec {
    private Configuration conf;
    // Hadoop config for how big to make intermediate buffers.
    private final String BUFFER_SIZE_CONFIG = "io.file.buffer.size";

    @Override
    public void setConf(Configuration conf) {
        this.conf = conf;
    }

    @Override
    public Configuration getConf() {
        return conf;
    }

    @Override
    public Compressor createCompressor() {
        return new SnappyCompressor();
    }

    @Override
    public Decompressor createDecompressor() {
        return new SnappyDecompressor();
    }

    @Override
    public CompressionInputStream createInputStream(InputStream stream)
            throws IOException {
        return createInputStream(stream, createDecompressor());
    }

    @Override
    public CompressionInputStream createInputStream(InputStream stream,
                                                    Decompressor decompressor) throws IOException {
        return new NonBlockedDecompressorStream(stream, decompressor,
                conf.getInt(BUFFER_SIZE_CONFIG, 4 * 1024));
    }

    @Override
    public CompressionOutputStream createOutputStream(OutputStream stream)
            throws IOException {
        return createOutputStream(stream, createCompressor());
    }

    @Override
    public CompressionOutputStream createOutputStream(OutputStream stream,
                                                      Compressor compressor) throws IOException {
        return new NonBlockedCompressorStream(stream, compressor,
                conf.getInt(BUFFER_SIZE_CONFIG, 4 * 1024));
    }

    @Override
    public Class<? extends Compressor> getCompressorType() {
        return SnappyCompressor.class;
    }

    @Override
    public Class<? extends Decompressor> getDecompressorType() {
        return SnappyDecompressor.class;
    }

    @Override
    public String getDefaultExtension() {
        return ".snappy";
    }
}