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KwargsKey class

A wrapper for keyword names (string literals) that internally stores a 64-bit hash value based on the BKDRHash algorithm.

Syntax

class KwargsKey;

Members

Constructors

Name Description
KwargsKey Constructor.

Types

Name Description
value_type The type of the string hash value; an unsigned 64-bit integer.

Functions

Name Description
value Returns the hash value.

Operators

Name Description
operator value_type() Implicit conversion to value_type.
operator== Hash value comparison.
operator!= Hash value comparison.
operator< Hash value comparison.
operator> Hash value comparison.
operator<= Hash value comparison.
operator>= Hash value comparison.
operator|| Joins two or more KwargsKey instances.

value_type

The type of the stored hash value. A 64-bit unsigned integer:

using value_type = detail::string_hash_type; // std::uint64_t

KwargsKey

Construct from a string literal:

template<std::size_t _Size>
constexpr KwargsKey(const char (&__str)[_Size]) noexcept;

Construct from a string pointer and length:

constexpr KwargsKey(const char* const __str, std::size_t __size) noexcept;

Tip

The __size does not need to include the null terminator \0. If it does, the \0 will also be hashed.

Construct directly from a precomputed hash value (not recommended):

constexpr explicit KwargsKey(value_type __option) noexcept;

value

Returns the internal hash value.

constexpr value_type value() const noexcept;

operator value_type()

Allows implicit conversion to value_type.

constexpr operator value_type() const noexcept;

operator<=> (Comparison Operators)

Compare based on hash values.

constexpr bool operator==(KwargsKey __other) const noexcept;
constexpr bool operator!=(KwargsKey __other) const noexcept;
constexpr bool operator<(KwargsKey __other) const noexcept;
constexpr bool operator>(KwargsKey __other) const noexcept;
constexpr bool operator<=(KwargsKey __other) const noexcept;
constexpr bool operator>=(KwargsKey __other) const noexcept;

Warning

Hash collisions may occur. Two different strings can have the same hash in extremely rare cases. However, identical strings will always produce the same hash.

operator||

Combines multiple KwargsKey instances using the or operator.

Supports combining keys using logical OR. See also Kwargs for usage.

friend constexpr std::array<KwargsKey, 2>
    operator||(KwargsKey __first, KwargsKey __second) noexcept;

template<std::size_t _StringSize>
friend constexpr std::array<KwargsKey, 2>
    operator||(KwargsKey __first, const char (&__second)[_StringSize]) noexcept;

template<std::size_t _Size>
friend constexpr std::array<KwargsKey, _Size + 1>
    operator||(const std::array<KwargsKey, _Size>& __first, KwargsKey __second) noexcept;

template<std::size_t _Size, std::size_t _StringSize>
friend constexpr std::array<KwargsKey, _Size + 1>
    operator||(const std::array<KwargsKey, _Size>& __first, const char (&__second)[_StringSize]) noexcept;