smtk::string::Token Class Reference

A string token identified by an integer. More...

#include <Token.h>

Collaboration diagram for smtk::string::Token:

Public Member Functions
	Token (const char *data=nullptr, std::size_t size=std::string::npos)
	Construct a token from a string literal.
	Token (const std::string &data)
	Construct a token from a std::string.
constexpr	Token (Hash tokenId) noexcept
	Construct a token given its hash value. More...
Hash	id () const
	Return the token's ID (usually its hash but possibly not in the case of collisions).
const std::string &	data () const
	Return the string corresponding to the token.
bool	hasData () const
	Return true if a string corresponding to the token exists.
bool	valid () const
	Return true if the token's ID has been set (false if not).
bool	operator== (const Token &other) const
	Fast equality comparison (compares hashes, not strings).
bool	operator!= (const Token &other) const
	Fast inequality comparison (compares hashes, not strings).
bool	operator< (const Token &other) const
	Slow, but unsurprising string comparison (preserves lexical string ordering).
bool	operator> (const Token &other) const
bool	operator<= (const Token &other) const
bool	operator>= (const Token &other) const

Static Public Member Functions
static Manager &	manager ()
	Return the database of strings and their tokens (hashes).
static constexpr Hash	stringHash (const char *data, std::size_t size) noexcept
	Return the hash of a string This is used internally but also by the ""_token() literal operator.
static Token	fromHash (Hash h)
	Construct a token given only its hash. More...

Static Public Attributes
static constexpr Hash	Invalid = Manager::Invalid
	An invalid hash, used with the constructor above to make an invalid token.

Static Protected Member Functions
template<typename T >
static constexpr std::enable_if< sizeof(T)==4, T >::type	hash_fnv1a_const (const char *str, std::size_t size, T value) noexcept
template<typename T >
static constexpr std::enable_if< sizeof(T)==4, std::size_t >::type	hash_fnv1a_seed ()
template<typename T >
static constexpr std::enable_if< sizeof(T)==8, std::size_t >::type	hash_fnv1a_const (const char *str, std::size_t size, uint64_t value) noexcept
template<typename T >
static constexpr std::enable_if< sizeof(T)==8, std::size_t >::type	hash_fnv1a_seed ()

Protected Attributes
Hash	m_id

Static Protected Attributes
static constexpr uint32_t	hash32a_const = 0x811c9dc5
static constexpr uint32_t	hash32b_const = 0x1000193
static constexpr uint64_t	hash64a_const = 0xcbf29ce484222325
static constexpr uint64_t	hash64b_const = 0x100000001b3
static std::shared_ptr< Manager >	s_manager

Detailed Description

A string token identified by an integer.

Often, it is useful for a common, variable-length string to be referenced indirectly rather than storing copies of the string. This class has a static database of hashes; each instance of the class holds only a fixed-size hash value. The string value can be produced in O(1) time by looking the hash up from the static database.

Constructor & Destructor Documentation

Token()

constexpr smtk::string::Token::Token ( Hash  tokenId )

inlineconstexprnoexcept

Construct a token given its hash value.

NOTE: This will NOT insert a string into the manager as other constructors do.

Member Function Documentation

fromHash()

Token smtk::string::Token::fromHash ( Hash  h )

static

Construct a token given only its hash.

This variant checks that the string manager holds data for the hash and will throw an exception if it does not.

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The documentation for this class was generated from the following files:

• /home/docs/checkouts/readthedocs.org/user_builds/smtk/checkouts/latest/smtk/string/Token.h
• /home/docs/checkouts/readthedocs.org/user_builds/smtk/checkouts/latest/smtk/string/Token.cxx