ClickHouse/dbms/Compression/CompressedWriteBuffer.cpp

#include <memory>
#include <city.h>
#include <string.h>

#include <common/unaligned.h>
#include <Core/Types.h>

#include "CompressedWriteBuffer.h"
#include <Compression/CompressionFactory.h>

#include <Common/MemorySanitizer.h>


namespace DB
{

namespace ErrorCodes
{
}

static constexpr auto CHECKSUM_SIZE{sizeof(CityHash_v1_0_2::uint128)};

void CompressedWriteBuffer::nextImpl()
{
    if (!offset())
        return;

    size_t decompressed_size = offset();
    UInt32 compressed_reserve_size = codec->getCompressedReserveSize(decompressed_size);
    compressed_buffer.resize(compressed_reserve_size);
    UInt32 compressed_size = codec->compress(working_buffer.begin(), decompressed_size, compressed_buffer.data());

    // FIXME remove this after fixing msan report in lz4.
    // Almost always reproduces on stateless tests, the exact test unknown.
    __msan_unpoison(compressed_buffer.data(), compressed_size);

    CityHash_v1_0_2::uint128 checksum = CityHash_v1_0_2::CityHash128(compressed_buffer.data(), compressed_size);
    out.write(reinterpret_cast<const char *>(&checksum), CHECKSUM_SIZE);
    out.write(compressed_buffer.data(), compressed_size);
}


CompressedWriteBuffer::CompressedWriteBuffer(
    WriteBuffer & out_,
    CompressionCodecPtr codec_,
    size_t buf_size)
    : BufferWithOwnMemory<WriteBuffer>(buf_size), out(out_), codec(std::move(codec_))
{
}

CompressedWriteBuffer::~CompressedWriteBuffer()
{
    try
    {
        next();
    }
    catch (...)
    {
        tryLogCurrentException(__PRETTY_FUNCTION__);
    }
}

}