Files
lwsf-wow/src/wire/wrapper/defaulted.h
T
Lee Clagett baaa19f2f4 Initial base set of code
This is far from complete, but has the basic structure and concepts
implemented. The remainder is just fill in the blanks, and testing.
2024-07-01 21:47:56 -04:00

79 lines
3.2 KiB
C++

// Copyright (c) 2021-2023, The Monero Project
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification, are
// permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this list of
// conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice, this list
// of conditions and the following disclaimer in the documentation and/or other
// materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its contributors may be
// used to endorse or promote products derived from this software without specific
// prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#pragma once
#include <functional>
#include <utility>
#include "wire/field.h"
#include "wire/traits.h"
//! An optional field that is omitted when a default value is used
#define WIRE_FIELD_DEFAULTED(name, default_) \
::wire::optional_field( #name , ::wire::defaulted(std::ref( self . name ), default_ ))
namespace wire
{
/*! A wrapper that tells `wire::writer`s to skip field generation when default
value, and tells `wire::reader`s to use default value when field not present. */
template<typename T, typename U>
struct defaulted_
{
using value_type = typename unwrap_reference<T>::type;
T value;
U default_;
constexpr const value_type& get_value() const noexcept { return value; }
value_type& get_value() noexcept { return value; }
// concept requirements for optional fields
constexpr explicit operator bool() const { return get_value() != default_; }
value_type& emplace() noexcept { return get_value(); }
constexpr const value_type& operator*() const noexcept { return get_value(); }
value_type& operator*() noexcept { return get_value(); }
void reset() { get_value() = default_; }
};
//! Links `value` with `default_`.
template<typename T, typename U>
inline constexpr defaulted_<T, U> defaulted(T value, U default_)
{
return {std::move(value), std::move(default_)};
}
/* read/write functions not needed since `defaulted_` meets the concept
requirements for an optional type (optional fields are handled
directly by the generic read/write code because the field name is omitted
entirely when the value is "empty"). */
} // wire