remove Maybe (use optional instead)
parent
0ee0d3231c
commit
1abf3bb3ad
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@ -13,21 +13,21 @@
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#include <string.h>
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#include <vector>
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#include <optional>
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#include "ostd/maybe.hh"
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#include "ostd/string.hh"
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/* TODO: make POSIX version thread safe, the Windows version is... */
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namespace ostd {
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inline Maybe<std::string> env_get(ConstCharRange name) {
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inline std::optional<std::string> env_get(ConstCharRange name) {
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char buf[256];
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auto tbuf = to_temp_cstr(name, buf, sizeof(buf));
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#ifndef OSTD_PLATFORM_WIN32
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char const *ret = getenv(tbuf.get());
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if (!ret) {
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return ostd::nothing;
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return std::nullopt;
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}
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return std::string{ret};
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#else
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@ -36,7 +36,7 @@ inline Maybe<std::string> env_get(ConstCharRange name) {
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for (;;) {
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sz = GetEnvironmentVariable(tbuf.get(), rbuf.data(), rbuf.capacity());
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if (!sz) {
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return ostd::nothing;
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return std::nullopt;
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}
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if (sz < rbuf.capacity()) {
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break;
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486
ostd/maybe.hh
486
ostd/maybe.hh
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@ -1,486 +0,0 @@
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/* Option type implementation. Inspired by libc++.
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*
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* This file is part of OctaSTD. See COPYING.md for futher information.
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*/
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#ifndef OSTD_MAYBE_HH
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#define OSTD_MAYBE_HH
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#include "ostd/types.hh"
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#include "ostd/type_traits.hh"
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#include "ostd/memory.hh"
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#include "ostd/utility.hh"
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#include "ostd/initializer_list.hh"
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#include "ostd/functional.hh"
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namespace ostd {
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struct InPlace {};
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constexpr InPlace in_place = InPlace();
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struct Nothing {
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explicit constexpr Nothing(int) {}
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};
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constexpr Nothing nothing = Nothing(0);
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namespace detail {
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template<typename T, bool = IsTriviallyDestructible<T>>
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class MaybeStorage {
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protected:
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using Value = T;
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union {
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char p_null_state;
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Value p_value;
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};
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bool p_engaged = false;
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constexpr MaybeStorage(): p_null_state('\0') {}
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MaybeStorage(MaybeStorage const &v): p_engaged(v.p_engaged) {
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if (p_engaged) {
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::new(address_of(p_value)) Value(v.p_value);
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}
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}
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MaybeStorage(MaybeStorage &&v): p_engaged(v.p_engaged) {
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if (p_engaged) {
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::new(address_of(p_value)) Value(std::move(v.p_value));
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}
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}
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constexpr MaybeStorage(Value const &v): p_value(v), p_engaged(true) {}
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constexpr MaybeStorage(Value &&v): p_value(std::move(v)), p_engaged(true) {}
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template<typename ...A>
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constexpr MaybeStorage(InPlace, A &&...args):
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p_value(std::forward<A>(args)...), p_engaged(true)
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{}
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~MaybeStorage() {
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if (p_engaged) {
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p_value.~Value();
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}
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}
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};
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template<typename T>
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class MaybeStorage<T, true> {
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protected:
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using Value = T;
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union {
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char p_null_state;
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Value p_value;
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};
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bool p_engaged = false;
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constexpr MaybeStorage(): p_null_state('\0') {}
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MaybeStorage(MaybeStorage const &v): p_engaged(v.p_engaged) {
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if (p_engaged) {
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::new(address_of(p_value)) Value(v.p_value);
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}
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}
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MaybeStorage(MaybeStorage &&v): p_engaged(v.p_engaged) {
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if (p_engaged) {
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::new(address_of(p_value)) Value(std::move(v.p_value));
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}
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}
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constexpr MaybeStorage(Value const &v): p_value(v), p_engaged(true) {}
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constexpr MaybeStorage(Value &&v): p_value(std::move(v)), p_engaged(true) {}
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template<typename ...A>
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constexpr MaybeStorage(InPlace, A &&...args):
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p_value(std::forward<A>(args)...), p_engaged(true)
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{}
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};
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}
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template<typename T>
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class Maybe: private detail::MaybeStorage<T> {
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using Base = detail::MaybeStorage<T>;
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public:
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using Value = T;
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static_assert(
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!IsReference<T>,
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"Initialization of Maybe with a reference type is not allowed."
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);
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static_assert(
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!IsSame<RemoveCv<T>, InPlace>,
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"Initialization of Maybe with InPlace is not allowed."
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);
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static_assert(
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!IsSame<RemoveCv<T>, Nothing>,
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"Initialization of Maybe with Nothing is not allowed."
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);
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static_assert(
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IsObject<T>,
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"Initialization of Maybe with non-object type is not allowed."
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);
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static_assert(
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IsDestructible<T>,
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"Initialization of Maybe with a non-destructible object is not allowed."
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);
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constexpr Maybe() {}
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Maybe(Maybe const &) = default;
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Maybe(Maybe &&) = default;
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constexpr Maybe(Nothing) {}
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constexpr Maybe(Value const &v): Base(v) {}
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constexpr Maybe(Value &&v): Base(std::move(v)) {}
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template<typename ...A, typename = EnableIf<IsConstructible<T, A...>>>
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constexpr explicit Maybe(InPlace, A &&...args):
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Base(in_place, std::forward<A>(args)...)
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{}
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template<typename U, typename ...A, typename = EnableIf<
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IsConstructible<T, std::initializer_list<U> &, A...>>
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>
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constexpr explicit Maybe(InPlace, std::initializer_list<U> il, A &&...args):
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Base(in_place, il, std::forward<A>(args)...)
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{}
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~Maybe() = default;
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Maybe &operator=(Nothing) {
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if (this->p_engaged) {
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this->p_value.~Value();
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this->p_engaged = false;
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}
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return *this;
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}
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Maybe &operator=(Maybe const &v) {
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if (this->p_engaged == v.p_engaged) {
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if (this->p_engaged) {
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this->p_value = v.p_value;
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}
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} else {
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if (this->p_engaged) {
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this->p_value.~Value();
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} else {
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::new(address_of(this->p_value)) Value(v.p_value);
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}
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this->p_engaged = v.p_engaged;
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}
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return *this;
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}
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Maybe &operator=(Maybe &&v) {
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if (this->p_engaged == v.p_engaged) {
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if (this->p_engaged) {
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this->p_value = std::move(v.p_value);
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}
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} else {
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if (this->p_engaged) {
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this->p_value.~Value();
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} else {
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::new(address_of(this->p_value)) Value(std::move(v.p_value));
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}
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this->p_engaged = v.p_engaged;
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}
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return *this;
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}
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template<typename U, typename = EnableIf<
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IsSame<RemoveReference<U>, Value> &&
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IsConstructible<Value, U> && IsAssignable<Value &, U>
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>>
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Maybe &operator=(U &&v) {
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if (this->p_engaged) {
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this->p_value = std::forward<U>(v);
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} else {
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::new(address_of(this->p_value)) Value(std::forward<U>(v));
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this->p_engaged = true;
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}
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return *this;
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}
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template<typename ...A, typename = EnableIf<IsConstructible<Value, A...>>>
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void emplace(A &&...args) {
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*this = nothing;
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::new(address_of(this->p_value)) Value(std::forward<A>(args)...);
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this->p_engaged = true;
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}
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template<typename U, typename ...A, typename = EnableIf<
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IsConstructible<Value, std::initializer_list<U> &, A...>
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>>
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void emplace(std::initializer_list<U> il, A &&...args) {
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*this = nothing;
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::new(address_of(this->p_value))
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Value(il, std::forward<A>(args)...);
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this->p_engaged = true;
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}
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constexpr Value const *operator->() const {
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return address_of(this->p_value);
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}
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constexpr Value *operator->() {
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return address_of(this->p_value);
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}
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constexpr Value const &operator*() const & {
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return this->p_value;
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}
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constexpr Value &operator*() & {
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return this->p_value;
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}
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constexpr Value const &&operator*() const && {
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return std::move(this->p_value);
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}
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constexpr Value &&operator*() && {
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return std::move(this->p_value);
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}
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constexpr explicit operator bool() const { return this->p_engaged; }
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constexpr Value const &value() const & {
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return this->p_value;
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}
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constexpr Value &value() & {
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return this->p_value;
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}
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constexpr Value const &&value() const && {
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return std::move(this->p_value);
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}
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constexpr Value &&value() && {
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return std::move(this->p_value);
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}
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template<typename U>
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constexpr Value value_or(U &&v) const & {
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static_assert(
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IsCopyConstructible<Value>,
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"Maybe<T>::value_or: T must be copy constructible"
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);
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static_assert(
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IsConvertible<U, Value>,
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"Maybe<T>::value_or: U must be convertible to T"
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);
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return this->p_engaged ? this->p_value : Value(std::forward<U>(v));
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}
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template<typename U>
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constexpr Value value_or(U &&v) && {
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static_assert(
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IsMoveConstructible<Value>,
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"Maybe<T>::value_or: T must be move constructible"
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);
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static_assert(
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IsConvertible<U, Value>,
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"Maybe<T>::value_or: U must be convertible to T"
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);
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return this->p_engaged ? std::move(this->p_value) : Value(std::forward<U>(v));
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}
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void swap(Maybe &v) {
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using std::swap;
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if (this->p_engaged == v.p_engaged) {
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if (this->p_engaged) {
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swap(this->p_value, v.p_value);
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}
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} else {
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if (this->p_engaged) {
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::new(address_of(v.p_value)) Value(std::move(this->p_value));
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this->p_value.~Value();
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} else {
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::new(address_of(this->p_value)) Value(std::move(v.p_value));
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v.p_value.~Value();
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}
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swap(this->p_engaged, v.p_engaged);
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}
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}
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};
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template<typename T>
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inline void swap(Maybe<T> &a, Maybe<T> &b) {
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a.swap(b);
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}
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/* maybe vs maybe */
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template<typename T>
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inline constexpr bool operator==(Maybe<T> const &a, Maybe<T> const &b) {
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return (bool(a) != bool(b)) ? false : (!bool(a) ? true : (*a == *b));
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}
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template<typename T>
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inline constexpr bool operator!=(Maybe<T> const &a, Maybe<T> const &b) {
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return !(a == b);
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}
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template<typename T>
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inline constexpr bool operator<(Maybe<T> const &a, Maybe<T> const &b) {
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return !bool(b) ? false : (!bool(a) ? true : (*a < *b));
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}
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template<typename T>
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inline constexpr bool operator>(Maybe<T> const &a, Maybe<T> const &b) {
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return b < a;
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}
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template<typename T>
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inline constexpr bool operator<=(Maybe<T> const &a, Maybe<T> const &b) {
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return !(b < a);
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}
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template<typename T>
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inline constexpr bool operator>=(Maybe<T> const &a, Maybe<T> const &b) {
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return !(a < b);
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}
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/* maybe vs nothing */
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template<typename T>
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inline constexpr bool operator==(Maybe<T> const &v, Nothing) {
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return !bool(v);
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}
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template<typename T>
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inline constexpr bool operator==(Nothing, Maybe<T> const &v) {
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return !bool(v);
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}
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template<typename T>
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inline constexpr bool operator!=(Maybe<T> const &v, Nothing) {
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return bool(v);
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}
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template<typename T>
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inline constexpr bool operator!=(Nothing, Maybe<T> const &v) {
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return bool(v);
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}
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template<typename T>
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inline constexpr bool operator<(Maybe<T> const &, Nothing) {
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return false;
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}
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template<typename T>
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inline constexpr bool operator<(Nothing, Maybe<T> const &v) {
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return bool(v);
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}
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template<typename T>
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inline constexpr bool operator<=(Maybe<T> const &v, Nothing) {
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return !bool(v);
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}
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template<typename T>
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inline constexpr bool operator<=(Nothing, Maybe<T> const &) {
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return true;
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}
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template<typename T>
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inline constexpr bool operator>(Maybe<T> const &v, Nothing) {
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return bool(v);
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}
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template<typename T>
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inline constexpr bool operator>(Nothing, Maybe<T> const &) {
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return false;
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}
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template<typename T>
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inline constexpr bool operator>=(Maybe<T> const &, Nothing) {
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return true;
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}
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template<typename T>
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inline constexpr bool operator>=(Nothing, Maybe<T> const &v) {
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return !bool(v);
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}
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/* maybe vs T */
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template<typename T>
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inline constexpr bool operator==(Maybe<T> const &a, T const &b) {
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return bool(a) ? (*a == b) : false;
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}
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template<typename T>
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inline constexpr bool operator==(T const &b, Maybe<T> const &a) {
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return bool(a) ? (*a == b) : false;
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}
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template<typename T>
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inline constexpr bool operator!=(Maybe<T> const &a, T const &b) {
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return bool(a) ? !(*a == b) : true;
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}
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template<typename T>
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inline constexpr bool operator!=(T const &b, Maybe<T> const &a) {
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return bool(a) ? !(*a == b) : true;
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}
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template<typename T>
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inline constexpr bool operator<(Maybe<T> const &a, T const &b) {
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return bool(a) ? Less<T>()(*a, b) : true;
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}
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template<typename T>
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inline constexpr bool operator<(T const &b, Maybe<T> const &a) {
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return bool(a) ? Less<T>()(b, *a) : false;
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}
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template<typename T>
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inline constexpr bool operator<=(Maybe<T> const &a, T const &b) {
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return !(a > b);
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}
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template<typename T>
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inline constexpr bool operator<=(T const &b, Maybe<T> const &a) {
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return !(b > a);
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}
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template<typename T>
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inline constexpr bool operator>(Maybe<T> const &a, T const &b) {
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return bool(a) ? (b < a) : true;
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}
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template<typename T>
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inline constexpr bool operator>(T const &b, Maybe<T> const &a) {
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return bool(a) ? (a < b) : true;
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}
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template<typename T>
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inline constexpr bool operator>=(Maybe<T> const &a, T const &b) {
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return !(a < b);
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}
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template<typename T>
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inline constexpr bool operator>=(T const &b, Maybe<T> const &a) {
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return !(b < a);
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}
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/* make maybe */
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template<typename T>
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inline constexpr Maybe<Decay<T>> make_maybe(T &&v) {
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return Maybe<Decay<T>>(std::forward<T>(v));
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}
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template<typename T, typename ...A>
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inline constexpr Maybe<T> make_maybe(A &&...args) {
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return Maybe<T>(in_place, std::forward<A>(args)...);
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}
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template<typename T, typename U, typename ...A>
|
||||
inline constexpr Maybe<T> make_maybe(std::initializer_list<U> il, A &&...args) {
|
||||
return Maybe<T>(in_place, il, std::forward<A>(args)...);
|
||||
}
|
||||
|
||||
} /* namespace ostd */
|
||||
|
||||
#endif
|
||||
Loading…
Reference in New Issue