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Fix hash

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This commit is contained in:
Simon Brand
2017-10-01 15:27:57 +01:00
parent da52667ac8
commit e390a1aadd
1 changed files with 16 additions and 8 deletions
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24
optional.hpp
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@ -14,6 +14,7 @@
#include <utility>
#include <exception>
#include <new>
#include <functional>
namespace tl {
template <class T> using remove_cv_t = typename std::remove_cv<T>::type;
@ -260,13 +261,12 @@ void swap(optional<T>& lhs, optional<T>& rhs) noexcept(noexcept(lhs.swap(rhs)))
}
}
// [optional.hash], hash support
// [optional.hash], hash support
namespace std {
template <class T> struct hash;
//TODO SFINAE
template <class T>
struct hash<tl::optional<T>> {
std::size_t operator() (const tl::optional<T>& o) {
std::size_t operator() (const tl::optional<T>& o) const {
if (!o.has_value())
return 0;
@ -280,6 +280,8 @@ namespace tl {
namespace detail {
template <class T, bool = std::is_trivially_destructible<T>::value>
struct optional_storage_base {
constexpr optional_storage_base() noexcept
: m_dummy(), m_has_value(false) {}
~optional_storage_base() {
if (m_has_value) {
m_value.~T();
@ -293,11 +295,13 @@ namespace tl {
T m_value;
};
bool m_has_value = false;
bool m_has_value;
};
template <class T>
struct optional_storage_base<T, true> {
constexpr optional_storage_base() noexcept
: m_dummy(), m_has_value(false) {}
~optional_storage_base() {
if (m_has_value) {
//don't destruct value
@ -548,16 +552,20 @@ class optional : private detail::optional_storage_base<T> {
return this->m_has_value;
}
constexpr const T& value() const& {
return has_value() ? this->m_value : throw bad_optional_access();
if (has_value()) return this->m_value;
throw bad_optional_access();
}
constexpr T& value() & {
return has_value() ? this->m_value : throw bad_optional_access();
if (has_value()) return this->m_value;
throw bad_optional_access();
}
constexpr T&& value() && {
return has_value() ? std::move(this->m_value) : throw bad_optional_access();
if (has_value()) return std::move(this->m_value);
throw bad_optional_access();
}
constexpr const T&& value() const&& {
return has_value() ? std::move(this->m_value) : throw bad_optional_access();
if (has_value()) return std::move(this->m_value);
throw bad_optional_access();
}
template <class U> constexpr T value_or(U&& u) const& {
static_assert(std::is_copy_constructible<T>::value && std::is_convertible<U&&, T>::value,