Files
doris/be/src/util/block_compression.h

67 lines
2.7 KiB
C++

// 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.
#pragma once
#include <cstddef>
#include <vector>
#include "common/status.h"
#include "gen_cpp/segment_v2.pb.h"
#include "util/slice.h"
namespace doris {
// This class is used to encapsulate Compression/Decompression algorithm.
// This class only used to compress a block data, which means all data
// should given when call compress or decompress. This class don't handle
// stream compression.
class BlockCompressionCodec {
public:
virtual ~BlockCompressionCodec() { }
// This function will compress input data into output.
// output should be preallocated, and its capacity must be large enough
// for compressed input, which can be get through max_compressed_len function.
// Size of compressed data will be set in output's size.
virtual Status compress(const Slice& input, Slice* output) const = 0;
// Default implementation will merge input list into a big buffer and call
// compress(Slice) to finish compression. If compression type support digesting
// slice one by one, it should reimplement this function.
virtual Status compress(const std::vector<Slice>& input, Slice* output) const;
// Decompress input data into output, output's capacity should be large enough
// for decompressed data.
// Size of decompressed data will be set in output's size.
virtual Status decompress(const Slice& input, Slice* output) const = 0;
// Returns an upper bound on the max compressed length.
virtual size_t max_compressed_len(size_t len) const = 0;
};
// Get a BlockCompressionCodec through type.
// Return Status::OK if a valid codec is found. If codec is null, it means it is
// NO_COMPRESSION. If codec is not null, user can use it to compress/decompress
// data. And client doesn't have to release the codec.
//
// Return not OK, if error happens.
Status get_block_compression_codec(
segment_v2::CompressionTypePB type, const BlockCompressionCodec** codec);
}