beedb/include/io/query_result_serializer.h

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2022-04-04 20:25:01 +02:00
/*------------------------------------------------------------------------------*
* Architecture & Implementation of DBMS *
*------------------------------------------------------------------------------*
* Copyright 2022 Databases and Information Systems Group TU Dortmund *
* Visit us at *
* http://dbis.cs.tu-dortmund.de/cms/en/home/ *
* *
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS *
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, *
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL *
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR *
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, *
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR *
* OTHER DEALINGS IN THE SOFTWARE. *
* *
* Authors: *
* Maximilian Berens <maximilian.berens@tu-dortmund.de> *
* Roland Kühn <roland.kuehn@cs.tu-dortmund.de> *
* Jan Mühlig <jan.muehlig@tu-dortmund.de> *
*------------------------------------------------------------------------------*
*/
#pragma once
#include "execution_callback.h"
#include <cstddef>
#include <string>
#include <table/schema.h>
#include <table/tuple.h>
#include <vector>
namespace beedb::io
{
/**
* Results of queries are serialized as follows:
* - First 2 bytes: Number of columns
* - For every column:
* - the type (table::Type)
* - the offset (std::size_t)
* - the column order index (std::uint16_t)
* - the null-terminated name of the column
* - After the schema, the bytes of the tuples will serialized.
*/
class QueryResultSerializer
{
public:
QueryResultSerializer();
~QueryResultSerializer();
void serialize(const table::Schema &schema);
void serialize(const table::Tuple &tuple);
[[nodiscard]] std::byte *data()
{
return _data;
}
[[nodiscard]] std::size_t size() const
{
return _size;
}
[[nodiscard]] bool empty() const
{
return _size == 0u;
}
private:
std::byte *_data = nullptr;
std::size_t _size = 0u;
std::size_t _capacity = 0u;
void append(const std::byte *data, const std::uint16_t size);
void prepend(const std::byte *data, const std::uint16_t size);
void allocate(const std::size_t capacity);
};
} // namespace beedb::io