544b3c9a34
This patch introduces type_info class which contains all type information needed by IMR deserialisation contexts.
66 lines
2.0 KiB
C++
66 lines
2.0 KiB
C++
/*
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* Copyright (C) 2018 ScyllaDB
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*/
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/*
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* This file is part of Scylla.
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*
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* Scylla is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* Scylla is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Scylla. If not, see <http://www.gnu.org/licenses/>.
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*/
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#pragma once
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#include <cstddef>
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namespace data {
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/// Type information
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///
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/// `type_info` keeps the type information relevant for the serialisation code.
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/// In particular we need to distinguish between fixed-size and variable-sized
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/// types. Collections and counters are considered to be variable-sized types.
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///
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/// \note Even if the type is fixed-size (e.g. `int32_type`) the value can be
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/// empty and its length will be 0. This is a special (and rare) case handled
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/// by the cell implementation and ignored by `type_info`.
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class type_info {
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size_t _fixed_size;
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private:
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explicit type_info(size_t size) noexcept : _fixed_size(size) { }
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public:
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static type_info make_fixed_size(size_t size) noexcept {
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return type_info { size_t(size) };
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}
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static type_info make_variable_size() noexcept {
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return type_info { 0 };
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}
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static type_info make_collection() noexcept {
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return type_info { 0 };
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}
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/// Check whether the type is fixed-size.
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bool is_fixed_size() const noexcept {
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return _fixed_size > 0;
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}
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/// Get the size of the value of a fixed-size type.
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///
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/// Valid only if `is_fixed_size()` returns `true`.
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size_t value_size() const noexcept {
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return _fixed_size;
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}
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};
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}
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