109 lines
2.8 KiB
C++
109 lines
2.8 KiB
C++
#pragma once
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#include <string>
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#include <utility>
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namespace nxst {
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template <class T, class E = std::string> class Result {
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bool ok;
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alignas(T) alignas(E) unsigned char storage[sizeof(T) > sizeof(E) ? sizeof(T) : sizeof(E)];
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Result() = default;
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public:
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static Result success(T val) {
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Result res;
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res.ok = true;
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new (res.storage) T(std::move(val));
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return res;
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}
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static Result failure(E err) {
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Result res;
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res.ok = false;
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new (res.storage) E(std::move(err));
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return res;
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}
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~Result() {
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if (ok)
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reinterpret_cast<T*>(storage)->~T();
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else
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reinterpret_cast<E*>(storage)->~E();
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}
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Result(const Result& other) : ok(other.ok) {
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if (ok)
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new (storage) T(*reinterpret_cast<const T*>(other.storage));
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else
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new (storage) E(*reinterpret_cast<const E*>(other.storage));
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}
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Result(Result&& other) : ok(other.ok) {
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if (ok)
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new (storage) T(std::move(*reinterpret_cast<T*>(other.storage)));
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else
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new (storage) E(std::move(*reinterpret_cast<E*>(other.storage)));
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}
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Result& operator=(const Result&) = delete;
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bool isOk() const noexcept {
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return ok;
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}
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const T& value() const {
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return *reinterpret_cast<const T*>(storage);
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}
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const E& error() const {
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return *reinterpret_cast<const E*>(storage);
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}
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};
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// Specialisation for Result<void>
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template <class E> class Result<void, E> {
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bool ok;
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alignas(E) unsigned char storage[sizeof(E)];
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Result() = default;
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public:
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static Result success() {
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Result res;
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res.ok = true;
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return res;
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}
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static Result failure(E err) {
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Result res;
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res.ok = false;
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new (res.storage) E(std::move(err));
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return res;
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}
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~Result() {
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if (!ok)
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reinterpret_cast<E*>(storage)->~E();
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}
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Result(const Result& other) : ok(other.ok) {
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if (!ok)
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new (storage) E(*reinterpret_cast<const E*>(other.storage));
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}
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Result(Result&& other) : ok(other.ok) {
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if (!ok)
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new (storage) E(std::move(*reinterpret_cast<E*>(other.storage)));
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}
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Result& operator=(const Result&) = delete;
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bool isOk() const noexcept {
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return ok;
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}
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const E& error() const {
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return *reinterpret_cast<const E*>(storage);
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}
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};
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} // namespace nxst
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