/*
* 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.hbase.io.encoding;
import java.io.IOException;
import java.nio.ByteBuffer;
import org.apache.hadoop.hbase.io.compress.Compression;
/**
* A decoding context that is created by a reader's encoder, and is shared
* across the reader's all read operations.
*
* @see HFileBlockEncodingContext for encoding
*/
public interface HFileBlockDecodingContext {
/**
* @return the compression algorithm used by this decoding context
*/
public Compression.Algorithm getCompression();
/**
* Perform all actions that need to be done before the encoder's real decoding process.
* Decompression needs to be done if {@link #getCompression()} returns a valid compression
* algorithm.
*
* @param onDiskSizeWithoutHeader numBytes after block and encoding headers
* @param uncompressedSizeWithoutHeader numBytes without header required to store the block after
* decompressing (not decoding)
* @param blockBufferWithoutHeader ByteBuffer pointed after the header but before the data
* @param onDiskBlock on disk bytes to be decoded
* @param offset data start offset in onDiskBlock
* @throws IOException
*/
public void prepareDecoding(int onDiskSizeWithoutHeader, int uncompressedSizeWithoutHeader,
ByteBuffer blockBufferWithoutHeader, byte[] onDiskBlock, int offset) throws IOException;
}