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#ifndef DIPLOMAT_RUNTIME_CPP_H
#define DIPLOMAT_RUNTIME_CPP_H
#include <string>
#include <variant>
#include <array>
#include <optional>
#include <type_traits>
#if __cplusplus >= 202002L
#include<span>
#endif
#include "diplomat_runtime.h"
namespace diplomat {
extern "C" inline void Flush(capi::DiplomatWriteable* w) {
std::string* string = reinterpret_cast<std::string*>(w->context);
string->resize(w->len);
};
extern "C" inline bool Grow(capi::DiplomatWriteable* w, uintptr_t requested) {
std::string* string = reinterpret_cast<std::string*>(w->context);
string->resize(requested);
w->cap = string->length();
w->buf = &(*string)[0];
return true;
};
inline capi::DiplomatWriteable WriteableFromString(std::string& string) {
capi::DiplomatWriteable w;
w.context = &string;
w.buf = &string[0];
w.len = string.length();
// Same as length, since C++ strings are not supposed
// to be written to past their len; you resize *first*
w.cap = string.length();
w.flush = Flush;
w.grow = Grow;
return w;
};
template<typename T> struct WriteableTrait {
// static inline capi::DiplomatWriteable Construct(T& t);
};
template<> struct WriteableTrait<std::string> {
static inline capi::DiplomatWriteable Construct(std::string& t) {
return diplomat::WriteableFromString(t);
}
};
template<class T> struct Ok {
T inner;
explicit Ok(T&& i): inner(std::move(i)) {}
// We don't want to expose an lvalue-capable constructor in general
// however there is no problem doing this for trivially copyable types
template<typename X = T, typename = typename std::enable_if<std::is_trivially_copyable<X>::value>::type>
explicit Ok(const T& i): inner(i) {}
Ok() = default;
Ok(Ok&&) noexcept = default;
Ok(const Ok &) = default;
Ok& operator=(const Ok&) = default;
Ok& operator=(Ok&&) noexcept = default;
};
template<class T> struct Err {
T inner;
explicit Err(T&& i): inner(std::move(i)) {}
// We don't want to expose an lvalue-capable constructor in general
// however there is no problem doing this for trivially copyable types
template<typename X = T, typename = typename std::enable_if<std::is_trivially_copyable<X>::value>::type>
explicit Err(const T& i): inner(i) {}
Err() = default;
Err(Err&&) noexcept = default;
Err(const Err &) = default;
Err& operator=(const Err&) = default;
Err& operator=(Err&&) noexcept = default;
};
template<class T, class E>
class result {
private:
std::variant<Ok<T>, Err<E>> val;
public:
explicit result(Ok<T>&& v): val(std::move(v)) {}
explicit result(Err<E>&& v): val(std::move(v)) {}
result() = default;
result(const result &) = default;
result& operator=(const result&) = default;
result& operator=(Ok<T>&& t) {
this->val = Ok<T>(std::move(t));
return *this;
}
result& operator=(Err<E>&& e) {
this->val = Err<E>(std::move(e));
return *this;
}
result& operator=(result&&) noexcept = default;
result(result &&) noexcept = default;
~result() = default;
bool is_ok() const {
return std::holds_alternative<Ok<T>>(this->val);
};
bool is_err() const {
return std::holds_alternative<Err<E>>(this->val);
};
std::optional<T> ok() && {
if (!this->is_ok()) {
return std::nullopt;
}
return std::make_optional(std::move(std::get<Ok<T>>(std::move(this->val)).inner));
};
std::optional<E> err() && {
if (!this->is_err()) {
return std::nullopt;
}
return std::make_optional(std::move(std::get<Err<E>>(std::move(this->val)).inner));
}
void set_ok(T&& t) {
this->val = Ok<T>(std::move(t));
}
void set_err(E&& e) {
this->val = Err<E>(std::move(e));
}
template<typename T2>
result<T2, E> replace_ok(T2&& t) {
if (this->is_err()) {
return result<T2, E>(Err<E>(std::get<Err<E>>(std::move(this->val))));
} else {
return result<T2, E>(Ok<T2>(std::move(t)));
}
}
};
// Use custom std::span on C++17, otherwise use std::span
#if __cplusplus >= 202002L
template<class T> using span = std::span<T>;
#else // __cplusplus >= 202002L
// C++-17-compatible std::span
template<class T>
class span {
public:
constexpr span(T* data, size_t size)
: data_(data), size_(size) {}
template<size_t N>
explicit constexpr span(std::array<typename std::remove_const<T>::type, N>& arr)
: data_(const_cast<T*>(arr.data())), size_(N) {}
constexpr T* data() const noexcept {
return this->data_;
}
constexpr size_t size() const noexcept {
return this->size_;
}
private:
T* data_;
size_t size_;
};
#endif // __cplusplus >= 202002L
}
#endif
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