Function checkAndWriteHeader

programs/compressor/Compressor.cpp:37–60

Outputs sizes of uncompressed and compressed blocks for compressed file.

/// Outputs sizes of uncompressed and compressed blocks for compressed file.
void checkAndWriteHeader(DB::ReadBuffer & in, DB::WriteBuffer & out)
{
    while (!in.eof())
    {
        in.ignore(16);    /// checksum

        char header[COMPRESSED_BLOCK_HEADER_SIZE];
        in.readStrict(header, COMPRESSED_BLOCK_HEADER_SIZE);

        UInt32 size_compressed = unalignedLoad<UInt32>(&header[1]);

        if (size_compressed > DBMS_MAX_COMPRESSED_SIZE)
            throw DB::Exception("Too large size_compressed. Most likely corrupted data.", DB::ErrorCodes::TOO_LARGE_SIZE_COMPRESSED);

        UInt32 size_decompressed = unalignedLoad<UInt32>(&header[5]);

        DB::writeText(size_decompressed, out);
        DB::writeChar('\t', out);
        DB::writeText(size_compressed, out);
        DB::writeChar('\n', out);

        in.ignore(size_compressed - COMPRESSED_BLOCK_HEADER_SIZE);
    }
}

}