tomlplusplus/include/toml++/toml_value.h
Mark Gillard 946a912cee added node::value() and node::value_or()
also:
- added `node_view::value`
- added relops for the date/time classes
- added `TOML_ALL_INLINE` and `TOML_IMPLEMENTATION` options
- fixed documentation header overflowing on narrow devices
2020-03-01 16:56:40 +02:00

452 lines
16 KiB
C++

#pragma once
#include "toml_node.h"
#include "toml_print_to_stream.h"
TOML_START
{
/// \brief A TOML value.
///
/// \tparam T The value's data type. Can be one of:
/// - toml::string
/// - int64_t
/// - double
/// - bool
/// - toml::date
/// - toml::time
/// - toml::date_time
template <typename T>
class value final : public node
{
static_assert(
impl::is_value<T>,
"Template type parameter must be one of the TOML value types"
);
private:
friend class impl::parser;
template <typename U, typename V>
[[nodiscard]] TOML_ALWAYS_INLINE
static auto as_value([[maybe_unused]] V* ptr) noexcept
{
if constexpr (std::is_same_v<T, U>)
return ptr;
else
return nullptr;
}
T val_;
public:
/// \brief The value's underlying data type.
using value_type = T;
/// \brief A type alias for 'value arguments'.
/// \details This differs according to the value's type argument:
/// - ints, floats, booleans: `value_type`
/// - strings: `string_view`
/// - everything else: `const value_type&`
using value_arg = std::conditional_t<
std::is_same_v<T, string>,
string_view,
std::conditional_t<impl::is_one_of<T, double, int64_t, bool>, T, const T&>
>;
/// \brief Constructs a toml value.
///
/// \tparam U Constructor argument types.
/// \param args Arguments to forward to the internal value's constructor.
template <typename... U>
TOML_NODISCARD_CTOR
explicit value(U&&... args) TOML_MAY_THROW_UNLESS(std::is_nothrow_constructible_v<T, U &&...>)
: val_{ std::forward<U>(args)... }
{}
/// \brief Move constructor.
TOML_NODISCARD_CTOR
value(value&& other) noexcept
: node{ std::move(other) },
val_{ std::move(other.val_) }
{}
/// \brief Move-assignment operator.
value& operator= (value&& rhs) noexcept
{
node::operator=(std::move(rhs));
val_ = std::move(rhs.val_);
return *this;
}
value(const value&) = delete;
value& operator= (const value&) = delete;
/// \brief Returns the value's node type identifier.
///
/// \returns One of:
/// - node_type::string
/// - node_type::integer
/// - node_type::floating_point
/// - node_type::boolean
/// - node_type::date
/// - node_type::time
/// - node_type::date_time
[[nodiscard]] node_type type() const noexcept override { return impl::node_type_of<T>; }
/// \brief Always returns `false` for value nodes.
[[nodiscard]] bool is_table() const noexcept override { return false; }
/// \brief Always returns `false` for value nodes.
[[nodiscard]] bool is_array() const noexcept override { return false; }
/// \brief Always returns `true` for value nodes.
[[nodiscard]] bool is_value() const noexcept override { return true; }
[[nodiscard]] bool is_string() const noexcept override { return std::is_same_v<T, string>; }
[[nodiscard]] bool is_integer() const noexcept override { return std::is_same_v<T, int64_t>; }
[[nodiscard]] bool is_floating_point() const noexcept override { return std::is_same_v<T, double>; }
[[nodiscard]] bool is_number() const noexcept override { return impl::is_one_of<T, int64_t, double>; }
[[nodiscard]] bool is_boolean() const noexcept override { return std::is_same_v<T, bool>; }
[[nodiscard]] bool is_date() const noexcept override { return std::is_same_v<T, date>; }
[[nodiscard]] bool is_time() const noexcept override { return std::is_same_v<T, time>; }
[[nodiscard]] bool is_date_time() const noexcept override { return std::is_same_v<T, date_time>; }
/// \brief Returns a pointer to the value if the data type is a string.
[[nodiscard]] value<string>* as_string() noexcept override { return as_value<string>(this); }
/// \brief Returns a pointer to the value if the data type is an integer.
[[nodiscard]] value<int64_t>* as_integer() noexcept override { return as_value<int64_t>(this); }
/// \brief Returns a pointer to the value if the data type is a floating-point.
[[nodiscard]] value<double>* as_floating_point() noexcept override { return as_value<double>(this); }
/// \brief Returns a pointer to the value if the data type is boolean.
[[nodiscard]] value<bool>* as_boolean() noexcept override { return as_value<bool>(this); }
/// \brief Returns a pointer to the value if the data type is a date.
[[nodiscard]] value<date>* as_date() noexcept override { return as_value<date>(this); }
/// \brief Returns a pointer to the value if the data type is a time.
[[nodiscard]] value<time>* as_time() noexcept override { return as_value<time>(this); }
/// \brief Returns a pointer to the value if the data type is date-time.
[[nodiscard]] value<date_time>* as_date_time() noexcept override { return as_value<date_time>(this); }
/// \brief Returns a const pointer to the value if the data type is a string.
[[nodiscard]] const value<string>* as_string() const noexcept override { return as_value<string>(this); }
/// \brief Returns a const pointer to the value if the data type is an integer.
[[nodiscard]] const value<int64_t>* as_integer() const noexcept override { return as_value<int64_t>(this); }
/// \brief Returns a const pointer to the value if the data type is a floating-point.
[[nodiscard]] const value<double>* as_floating_point() const noexcept override { return as_value<double>(this); }
/// \brief Returns a const pointer to the value if the data type is a boolean.
[[nodiscard]] const value<bool>* as_boolean() const noexcept override { return as_value<bool>(this); }
/// \brief Returns a const pointer to the value if the data type is a date.
[[nodiscard]] const value<date>* as_date() const noexcept override { return as_value<date>(this); }
/// \brief Returns a const pointer to the value if the data type is a time.
[[nodiscard]] const value<time>* as_time() const noexcept override { return as_value<time>(this); }
/// \brief Returns a const pointer to the value if the data type is a date-time.
[[nodiscard]] const value<date_time>* as_date_time() const noexcept override { return as_value<date_time>(this); }
/// \brief Returns a reference to the underlying value.
[[nodiscard]] T& get() & noexcept { return val_; }
/// \brief Returns a reference to the underlying value (rvalue overload).
[[nodiscard]] T&& get() && noexcept { return std::move(val_); }
/// \brief Returns a reference to the underlying value (const overload).
[[nodiscard]] const T& get() const & noexcept { return val_; }
/// \brief Returns a reference to the underlying value.
[[nodiscard]] T& operator* () & noexcept { return val_; }
/// \brief Returns a reference to the underlying value (rvalue overload).
[[nodiscard]] T&& operator* () && noexcept { return std::move(val_); }
/// \brief Returns a reference to the underlying value (const overload).
[[nodiscard]] const T& operator* () const& noexcept { return val_; }
/// \brief Returns a reference to the underlying value.
[[nodiscard]] explicit operator T& () & noexcept { return val_; }
/// \brief Returns a reference to the underlying value (rvalue overload).
[[nodiscard]] explicit operator T&& () && noexcept { return std::move(val_); }
/// \brief Returns a reference to the underlying value (const overload).
[[nodiscard]] explicit operator const T& () const& noexcept { return val_; }
template <typename CHAR>
friend std::basic_ostream<CHAR>& operator << (std::basic_ostream<CHAR>& lhs, const value& rhs) TOML_MAY_THROW
{
// this is the same behaviour as default_formatter, but it's so simple that there's
// no need to spin up a new instance of it just for individual values.
if constexpr (std::is_same_v<T, string>)
{
impl::print_to_stream('"', lhs);
impl::print_to_stream_with_escapes(rhs.val_, lhs);
impl::print_to_stream('"', lhs);
}
else
impl::print_to_stream(rhs.val_, lhs);
return lhs;
}
/// \brief Value-assignment operator.
value& operator= (value_arg rhs) noexcept
{
if constexpr (std::is_same_v<T, string>)
val_.assign(rhs);
else
val_ = rhs;
return *this;
}
template <typename U = T, typename = std::enable_if_t<std::is_same_v<U, string>>>
value& operator= (string&& rhs) noexcept
{
val_ = std::move(rhs);
return *this;
}
/// \brief Value equality operator.
[[nodiscard]] friend bool operator == (const value& lhs, value_arg rhs) noexcept { return lhs.val_ == rhs; }
TOML_ASYMMETRICAL_EQUALITY_OPS(const value&, value_arg, )
/// \brief Value less-than operator.
[[nodiscard]] friend bool operator < (const value& lhs, value_arg rhs) noexcept { return lhs.val_ < rhs; }
/// \brief Value less-than operator.
[[nodiscard]] friend bool operator < (value_arg lhs, const value& rhs) noexcept { return lhs < rhs.val_; }
/// \brief Value less-than-or-equal-to operator.
[[nodiscard]] friend bool operator <= (const value& lhs, value_arg rhs) noexcept { return lhs.val_ <= rhs; }
/// \brief Value less-than-or-equal-to operator.
[[nodiscard]] friend bool operator <= (value_arg lhs, const value& rhs) noexcept { return lhs <= rhs.val_; }
/// \brief Value greater-than operator.
[[nodiscard]] friend bool operator > (const value& lhs, value_arg rhs) noexcept { return lhs.val_ > rhs; }
/// \brief Value greater-than operator.
[[nodiscard]] friend bool operator > (value_arg lhs, const value& rhs) noexcept { return lhs > rhs.val_; }
/// \brief Value greater-than-or-equal-to operator.
[[nodiscard]] friend bool operator >= (const value& lhs, value_arg rhs) noexcept { return lhs.val_ >= rhs; }
/// \brief Value greater-than-or-equal-to operator.
[[nodiscard]] friend bool operator >= (value_arg lhs, const value& rhs) noexcept { return lhs >= rhs.val_; }
/// \brief Equality operator.
///
/// \param lhs The LHS value.
/// \param rhs The RHS value.
///
/// \returns True if the values were of the same type and contained the same value.
template <typename U>
[[nodiscard]] friend bool operator == (const value& lhs, const value<U>& rhs) noexcept
{
if constexpr (std::is_same_v<T, U>)
return lhs.val_ == rhs.val_;
else
return false;
}
/// \brief Inequality operator.
///
/// \param lhs The LHS value.
/// \param rhs The RHS value.
///
/// \returns True if the values were not of the same type, or did not contain the same value.
template <typename U>
[[nodiscard]] friend bool operator != (const value& lhs, const value<U>& rhs) noexcept
{
return !(lhs == rhs);
}
/// \brief Less-than operator.
///
/// \param lhs The LHS toml::value.
/// \param rhs The RHS toml::value.
///
/// \returns <strong><em>Same value types:</em></strong> `lhs.get() < rhs.get()` <br>
/// <strong><em>Different value types:</em></strong> `lhs.type() < rhs.type()`
template <typename U>
[[nodiscard]] friend bool operator < (const value& lhs, const value<U>& rhs) noexcept
{
if constexpr (std::is_same_v<T, U>)
return lhs.val_ < rhs.val_;
else
return impl::node_type_of<T> < impl::node_type_of<U>;
}
/// \brief Less-than-or-equal-to operator.
///
/// \param lhs The LHS toml::value.
/// \param rhs The RHS toml::value.
///
/// \returns <strong><em>Same value types:</em></strong> `lhs.get() <= rhs.get()` <br>
/// <strong><em>Different value types:</em></strong> `lhs.type() <= rhs.type()`
template <typename U>
[[nodiscard]] friend bool operator <= (const value& lhs, const value<U>& rhs) noexcept
{
if constexpr (std::is_same_v<T, U>)
return lhs.val_ <= rhs.val_;
else
return impl::node_type_of<T> <= impl::node_type_of<U>;
}
/// \brief Greater-than operator.
///
/// \param lhs The LHS toml::value.
/// \param rhs The RHS toml::value.
///
/// \returns <strong><em>Same value types:</em></strong> `lhs.get() > rhs.get()` <br>
/// <strong><em>Different value types:</em></strong> `lhs.type() > rhs.type()`
template <typename U>
[[nodiscard]] friend bool operator > (const value& lhs, const value<U>& rhs) noexcept
{
if constexpr (std::is_same_v<T, U>)
return lhs.val_ > rhs.val_;
else
return impl::node_type_of<T> > impl::node_type_of<U>;
}
/// \brief Greater-than-or-equal-to operator.
///
/// \param lhs The LHS toml::value.
/// \param rhs The RHS toml::value.
///
/// \returns <strong><em>Same value types:</em></strong> `lhs.get() >= rhs.get()` <br>
/// <strong><em>Different value types:</em></strong> `lhs.type() >= rhs.type()`
template <typename U>
[[nodiscard]] friend bool operator >= (const value& lhs, const value<U>& rhs) noexcept
{
if constexpr (std::is_same_v<T, U>)
return lhs.val_ >= rhs.val_;
else
return impl::node_type_of<T> >= impl::node_type_of<U>;
}
};
template <size_t N> value(const string_char(&)[N]) -> value<string>;
template <size_t N> value(const string_char(&&)[N]) -> value<string>;
value(const string_char*) -> value<string>;
template <size_t N> value(string_char(&)[N]) -> value<string>;
template <size_t N> value(string_char(&&)[N]) -> value<string>;
value(string_char*) -> value<string>;
value(string_view) -> value<string>;
value(string) -> value<string>;
value(bool) -> value<bool>;
value(float) -> value<double>;
value(double) -> value<double>;
value(int8_t) -> value<int64_t>;
value(int16_t) -> value<int64_t>;
value(int32_t) -> value<int64_t>;
value(int64_t) -> value<int64_t>;
value(uint8_t) -> value<int64_t>;
value(uint16_t) -> value<int64_t>;
value(uint32_t) -> value<int64_t>;
value(date) -> value<date>;
value(time) -> value<time>;
value(date_time) -> value<date_time>;
#ifdef TOML_SMALL_FLOAT_TYPE
value(TOML_SMALL_FLOAT_TYPE) -> value<double>;
#endif
#ifdef TOML_SMALL_INT_TYPE
value(TOML_SMALL_INT_TYPE) -> value<int64_t>;
#endif
template <typename T>
inline std::optional<T> node::value() const noexcept
{
static_assert(
impl::is_value<T> || std::is_same_v<T, string_view>,
"Value type must be one of the TOML value types (or string_view)"
);
switch (type())
{
case node_type::none: [[fallthrough]];
case node_type::table: [[fallthrough]];
case node_type::array:
return {};
case node_type::string:
{
if constexpr (std::is_same_v<T, string> || std::is_same_v<T, string_view>)
return { T{ ref_cast<string>().get() } };
else
return {};
}
case node_type::integer:
{
if constexpr (std::is_same_v<T, int64_t>)
return ref_cast<int64_t>().get();
else if constexpr (std::is_same_v<T, double>)
return static_cast<double>(ref_cast<int64_t>().get());
else
return {};
}
case node_type::floating_point:
{
if constexpr (std::is_same_v<T, double>)
return ref_cast<double>().get();
else if constexpr (std::is_same_v<T, int64_t>)
return static_cast<int64_t>(ref_cast<double>().get());
else
return {};
}
case node_type::boolean:
{
if constexpr (std::is_same_v<T, bool>)
return ref_cast<bool>().get();
else
return {};
}
case node_type::date:
{
if constexpr (std::is_same_v<T, date>)
return ref_cast<date>().get();
else
return {};
}
case node_type::time:
{
if constexpr (std::is_same_v<T, time>)
return ref_cast<time>().get();
else
return {};
}
case node_type::date_time:
{
if constexpr (std::is_same_v<T, date_time>)
return ref_cast<date_time>().get();
else
return {};
}
TOML_NO_DEFAULT_CASE;
}
TOML_UNREACHABLE;
}
template <typename T>
inline auto node::value_or(T&& default_value) const noexcept
{
static_assert(
impl::is_value_or_promotable<impl::remove_cvref_t<T>>,
"Default value type must be (or be promotable to) one of the TOML value types"
);
using value_type = impl::promoted<impl::remove_cvref_t<T>>;
using return_type = std::conditional_t<
std::is_same_v<value_type, string>,
std::conditional_t<std::is_same_v<impl::remove_cvref_t<T>, string>, string, string_view>,
value_type
>;
if (auto val = this->value<return_type>())
return *val;
return return_type{ std::forward<T>(default_value) };
}
#if !TOML_ALL_INLINE
extern template class value<string>;
extern template class value<int64_t>;
extern template class value<double>;
extern template class value<bool>;
extern template class value<date>;
extern template class value<time>;
extern template class value<date_time>;
#endif
}
TOML_END