|
|
#ifndef OPAQUE_CONVERT_HPP
|
|
|
#define OPAQUE_CONVERT_HPP
|
|
|
//
|
|
|
// Copyright (c) 2015, 2016
|
|
|
// Kyle Markley. 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 author nor the names of any 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.
|
|
|
//
|
|
|
#include "type_traits.hpp"
|
|
|
#include "utility.hpp"
|
|
|
#include "data.hpp"
|
|
|
#include <type_traits>
|
|
|
|
|
|
namespace opaque {
|
|
|
|
|
|
/// \addtogroup internal
|
|
|
/// @{
|
|
|
|
|
|
//
|
|
|
// Conversion operations
|
|
|
//
|
|
|
// Convert from one type to a compatible type, avoiding creating a new object
|
|
|
// when possible. The function determines whether the output must be mutable
|
|
|
// or may be const.
|
|
|
//
|
|
|
// The cost model is:
|
|
|
// 0 = free case
|
|
|
// 1 = construction from rvalue reference
|
|
|
// 2 = construction from lvalue reference
|
|
|
//
|
|
|
|
|
|
template <typename T, typename U=T,
|
|
|
bool free = is_cast_free<T, typename std::decay<U>::type>::value>
|
|
|
struct converter;
|
|
|
|
|
|
template <typename T, typename U>
|
|
|
struct converter<T, const U&, true> {
|
|
|
|
|
|
static constexpr T convert_mutable(const U& u) noexcept(
|
|
|
noexcept(static_cast< T >(u))) {
|
|
|
return static_cast< T >(u); }
|
|
|
|
|
|
static constexpr const T& convert( const U& u) noexcept(
|
|
|
noexcept(static_cast<const T& >(u))) {
|
|
|
return static_cast<const T& >(u); }
|
|
|
|
|
|
static constexpr unsigned mutable_cost() noexcept { return 2; }
|
|
|
static constexpr unsigned cost() noexcept { return 0; }
|
|
|
|
|
|
};
|
|
|
|
|
|
template <typename T, typename U>
|
|
|
struct converter<T, U&, true> {
|
|
|
|
|
|
static constexpr T& convert_mutable( U& u) noexcept(
|
|
|
noexcept(static_cast< T& >(u))) {
|
|
|
return static_cast< T& >(u); }
|
|
|
|
|
|
static constexpr T& convert( U& u) noexcept(
|
|
|
noexcept(static_cast< T& >(u))) {
|
|
|
return static_cast< T& >(u); }
|
|
|
|
|
|
static constexpr unsigned mutable_cost() noexcept { return 0; }
|
|
|
static constexpr unsigned cost() noexcept { return 0; }
|
|
|
|
|
|
};
|
|
|
|
|
|
template <typename T, typename U>
|
|
|
struct converter<T, U&&, true> {
|
|
|
|
|
|
static constexpr T&& convert_mutable( U&& u) noexcept(
|
|
|
noexcept(static_cast< T&&>(opaque::move(u)))) {
|
|
|
return static_cast< T&&>(opaque::move(u)); }
|
|
|
|
|
|
static constexpr T&& convert( U&& u) noexcept(
|
|
|
noexcept(static_cast< T&&>(opaque::move(u)))) {
|
|
|
return static_cast< T&&>(opaque::move(u)); }
|
|
|
|
|
|
static constexpr unsigned mutable_cost() noexcept { return 0; }
|
|
|
static constexpr unsigned cost() noexcept { return 0; }
|
|
|
|
|
|
};
|
|
|
|
|
|
template <typename T, typename U>
|
|
|
struct converter<T, U, true> { // same as U&&
|
|
|
|
|
|
static constexpr T&& convert_mutable( U&& u) noexcept(
|
|
|
noexcept(static_cast< T&&>(opaque::move(u)))) {
|
|
|
return static_cast< T&&>(opaque::move(u)); }
|
|
|
|
|
|
static constexpr T&& convert( U&& u) noexcept(
|
|
|
noexcept(static_cast< T&&>(opaque::move(u)))) {
|
|
|
return static_cast< T&&>(opaque::move(u)); }
|
|
|
|
|
|
static constexpr unsigned mutable_cost() noexcept { return 0; }
|
|
|
static constexpr unsigned cost() noexcept { return 0; }
|
|
|
|
|
|
};
|
|
|
|
|
|
template <typename T, typename U>
|
|
|
struct converter<T, const U&, false> {
|
|
|
|
|
|
template <typename R=T>
|
|
|
static constexpr
|
|
|
typename std::enable_if<not std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type convert_mutable(const U& u) noexcept(
|
|
|
noexcept(static_cast<R>(u))) {
|
|
|
return static_cast<R>(u); }
|
|
|
|
|
|
template <typename R=T>
|
|
|
static constexpr
|
|
|
typename std::enable_if< std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type convert_mutable(const U& u) noexcept(
|
|
|
noexcept(static_cast<R>(u.value))) {
|
|
|
return static_cast<R>(u.value); }
|
|
|
|
|
|
template <typename R=T>
|
|
|
static constexpr
|
|
|
typename std::enable_if<not std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type convert( const U& u) noexcept(
|
|
|
noexcept(static_cast<R>(u))) {
|
|
|
return static_cast<R>(u); }
|
|
|
|
|
|
template <typename R=const T&>
|
|
|
static constexpr
|
|
|
typename std::enable_if< std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type convert( const U& u) noexcept(
|
|
|
noexcept(static_cast<R>(u.value))) {
|
|
|
return static_cast<R>(u.value); }
|
|
|
|
|
|
template <typename R=unsigned>
|
|
|
static constexpr
|
|
|
typename std::enable_if<not std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type mutable_cost() noexcept { return 2; }
|
|
|
template <typename R=unsigned>
|
|
|
static constexpr
|
|
|
typename std::enable_if< std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type mutable_cost() noexcept { return 2; }
|
|
|
template <typename R=unsigned>
|
|
|
static constexpr
|
|
|
typename std::enable_if<not std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type cost() noexcept { return 2; }
|
|
|
template <typename R=unsigned>
|
|
|
static constexpr
|
|
|
typename std::enable_if< std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type cost() noexcept { return 0; }
|
|
|
|
|
|
};
|
|
|
|
|
|
template <typename T, typename U>
|
|
|
struct converter<T, U&, false> {
|
|
|
|
|
|
template <typename R=T>
|
|
|
static constexpr
|
|
|
typename std::enable_if<not std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type convert_mutable( U& u) noexcept(
|
|
|
noexcept(static_cast<R>(u))) {
|
|
|
return static_cast<R>(u); }
|
|
|
|
|
|
template <typename R=T&>
|
|
|
static constexpr
|
|
|
typename std::enable_if< std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type convert_mutable( U& u) noexcept(
|
|
|
noexcept(static_cast<R>(u.value))) {
|
|
|
return static_cast<R>(u.value); }
|
|
|
|
|
|
template <typename R=T>
|
|
|
static constexpr
|
|
|
typename std::enable_if<not std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type convert( U& u) noexcept(
|
|
|
noexcept(static_cast<R>(u))) {
|
|
|
return static_cast<R>(u); }
|
|
|
|
|
|
template <typename R=T&>
|
|
|
static constexpr
|
|
|
typename std::enable_if< std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type convert( U& u) noexcept(
|
|
|
noexcept(static_cast<R>(u.value))) {
|
|
|
return static_cast<R>(u.value); }
|
|
|
|
|
|
template <typename R=unsigned>
|
|
|
static constexpr
|
|
|
typename std::enable_if<not std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type mutable_cost() noexcept { return 2; }
|
|
|
template <typename R=unsigned>
|
|
|
static constexpr
|
|
|
typename std::enable_if< std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type mutable_cost() noexcept { return 0; }
|
|
|
template <typename R=unsigned>
|
|
|
static constexpr
|
|
|
typename std::enable_if<not std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type cost() noexcept { return 2; }
|
|
|
template <typename R=unsigned>
|
|
|
static constexpr
|
|
|
typename std::enable_if< std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type cost() noexcept { return 0; }
|
|
|
};
|
|
|
|
|
|
|
|
|
template <typename T, typename U>
|
|
|
struct converter<T, U&&, false> {
|
|
|
|
|
|
template <typename R=T>
|
|
|
static constexpr
|
|
|
typename std::enable_if<not std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type convert_mutable( U&& u) noexcept(
|
|
|
noexcept(static_cast<R>(opaque::move(u)))) {
|
|
|
return static_cast<R>(opaque::move(u)); }
|
|
|
|
|
|
template <typename R=T&&>
|
|
|
static constexpr
|
|
|
typename std::enable_if< std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type convert_mutable( U&& u) noexcept(
|
|
|
noexcept(static_cast<R>(opaque::move(u.value)))) {
|
|
|
return static_cast<R>(opaque::move(u.value)); }
|
|
|
|
|
|
template <typename R=T>
|
|
|
static constexpr
|
|
|
typename std::enable_if<not std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type convert( U&& u) noexcept(
|
|
|
noexcept(static_cast<R>(opaque::move(u)))) {
|
|
|
return static_cast<R>(opaque::move(u)); }
|
|
|
|
|
|
template <typename R=T&&>
|
|
|
static constexpr
|
|
|
typename std::enable_if< std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type convert( U&& u) noexcept(
|
|
|
noexcept(static_cast<R>(opaque::move(u.value)))) {
|
|
|
return static_cast<R>(opaque::move(u.value)); }
|
|
|
|
|
|
template <typename R=unsigned>
|
|
|
static constexpr
|
|
|
typename std::enable_if<not std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type mutable_cost() noexcept { return 1; }
|
|
|
template <typename R=unsigned>
|
|
|
static constexpr
|
|
|
typename std::enable_if< std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type mutable_cost() noexcept { return 0; }
|
|
|
template <typename R=unsigned>
|
|
|
static constexpr
|
|
|
typename std::enable_if<not std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type cost() noexcept { return 1; }
|
|
|
template <typename R=unsigned>
|
|
|
static constexpr
|
|
|
typename std::enable_if< std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type cost() noexcept { return 0; }
|
|
|
};
|
|
|
|
|
|
|
|
|
template <typename T, typename U>
|
|
|
struct converter<T, U, false> { // same as U&&
|
|
|
|
|
|
template <typename R=T>
|
|
|
static constexpr
|
|
|
typename std::enable_if<not std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type convert_mutable( U&& u) noexcept(
|
|
|
noexcept(static_cast<R>(opaque::move(u)))) {
|
|
|
return static_cast<R>(opaque::move(u)); }
|
|
|
|
|
|
template <typename R=T&&>
|
|
|
static constexpr
|
|
|
typename std::enable_if< std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type convert_mutable( U&& u) noexcept(
|
|
|
noexcept(static_cast<R>(opaque::move(u.value)))) {
|
|
|
return static_cast<R>(opaque::move(u.value)); }
|
|
|
|
|
|
template <typename R=T>
|
|
|
static constexpr
|
|
|
typename std::enable_if<not std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type convert( U&& u) noexcept(
|
|
|
noexcept(static_cast<R>(opaque::move(u)))) {
|
|
|
return static_cast<R>(opaque::move(u)); }
|
|
|
|
|
|
template <typename R=T&&>
|
|
|
static constexpr
|
|
|
typename std::enable_if< std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type convert( U&& u) noexcept(
|
|
|
noexcept(static_cast<R>(opaque::move(u.value)))) {
|
|
|
return static_cast<R>(opaque::move(u.value)); }
|
|
|
|
|
|
template <typename R=unsigned>
|
|
|
static constexpr
|
|
|
typename std::enable_if<not std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type mutable_cost() noexcept { return 1; }
|
|
|
template <typename R=unsigned>
|
|
|
static constexpr
|
|
|
typename std::enable_if< std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type mutable_cost() noexcept { return 0; }
|
|
|
template <typename R=unsigned>
|
|
|
static constexpr
|
|
|
typename std::enable_if<not std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type cost() noexcept { return 1; }
|
|
|
template <typename R=unsigned>
|
|
|
static constexpr
|
|
|
typename std::enable_if< std::is_base_of<data<T,U>, U>::value,
|
|
|
R>::type cost() noexcept { return 0; }
|
|
|
|
|
|
};
|
|
|
|
|
|
///
|
|
|
/// Convert the argument and ensure the result is mutable
|
|
|
///
|
|
|
/// Where possible, the conversion is performed via a no-cost cast (perhaps an
|
|
|
/// up or down cast), but for unrelated or const types, a new object is
|
|
|
/// created.
|
|
|
///
|
|
|
template <typename T, typename U=T>
|
|
|
constexpr auto convert_mutable(U&& u)
|
|
|
noexcept(noexcept(
|
|
|
converter<typename std::decay<T>::type, U>::convert_mutable(
|
|
|
opaque::forward<U>(u)))) -> decltype(
|
|
|
converter<typename std::decay<T>::type, U>::convert_mutable(
|
|
|
opaque::forward<U>(u))) { return
|
|
|
converter<typename std::decay<T>::type, U>::convert_mutable(
|
|
|
opaque::forward<U>(u));
|
|
|
}
|
|
|
|
|
|
///
|
|
|
/// Convert the argument
|
|
|
///
|
|
|
/// Where possible, the conversion is performed via a no-cost cast (perhaps an
|
|
|
/// up or down cast), but for unrelated types, a new object is created.
|
|
|
///
|
|
|
template <typename T, typename U=T>
|
|
|
constexpr auto convert(U&& u)
|
|
|
noexcept(noexcept(
|
|
|
converter<typename std::decay<T>::type, U>::convert(
|
|
|
opaque::forward<U>(u)))) -> decltype(
|
|
|
converter<typename std::decay<T>::type, U>::convert(
|
|
|
opaque::forward<U>(u))) { return
|
|
|
converter<typename std::decay<T>::type, U>::convert(
|
|
|
opaque::forward<U>(u));
|
|
|
}
|
|
|
|
|
|
template <typename T, typename U>
|
|
|
constexpr unsigned convert_mutable_cost() noexcept {
|
|
|
return converter<typename std::decay<T>::type, U&&>::mutable_cost();
|
|
|
}
|
|
|
|
|
|
template <typename T, typename U>
|
|
|
constexpr unsigned convert_mutable_cost(U&&) noexcept {
|
|
|
return converter<typename std::decay<T>::type, U&&>::mutable_cost();
|
|
|
}
|
|
|
|
|
|
template <typename T, typename U>
|
|
|
constexpr unsigned convert_cost() noexcept {
|
|
|
return converter<typename std::decay<T>::type, U&&>::cost();
|
|
|
}
|
|
|
|
|
|
template <typename T, typename U>
|
|
|
constexpr unsigned convert_cost(U&&) noexcept {
|
|
|
return converter<typename std::decay<T>::type, U&&>::cost();
|
|
|
}
|
|
|
|
|
|
/// @}
|
|
|
|
|
|
}
|
|
|
|
|
|
#endif
|
|
|
|