Helper class for efficient "key" access for strings. More...

#include </builds/gaudi/Gaudi/GaudiKernel/include/GaudiKernel/StringKey.h>

Collaboration diagram for Gaudi::StringKey:

[legend]

Public Member Functions
	StringKey ()
	Default constructor from empty string.

	StringKey (const char *key)
	constructor from plain C-string, perform hashing

	StringKey (std::string_view key)
	constructor from std::string_view, perform hashing

	StringKey (std::string key)
	constructor from std::string, perform hashing

const std::string &	str () const
	the actual string

	operator const std::string & () const
	implicit cast to std::string

	operator std::string_view () const
	implicit cast to std::string_view

bool	empty () const
	empty key?

bool	operator! () const
	empty key?

bool	operator== (const StringKey &) const =default
	Compiler generated equality operator first comparing hash, then string (see below)

auto	operator<=> (const StringKey &) const =default
	Compiler generated spaceship operator first comparing hash, then string (see below)

bool	operator== (const char *rhs) const
	Comparison to other string-like types.

bool	operator== (std::string_view rhs) const

bool	operator== (const std::string &rhs) const

std::size_t	__hash__ () const
	the actual access to the hash

const std::string &	__str__ () const
	the representation of the object

std::string	__repr__ () const
	the representation of the object

bool	__eq__ (const StringKey &right) const
	equality operator for python

bool	__eq__ (std::string_view right) const
	equality operators for python

bool	__neq__ (const StringKey &right) const
	non-equality operator for python

bool	__neq__ (const std::string_view right) const
	non-equality operator for python

std::string	toString () const
	string representation (for properties)

Private Attributes
std::size_t	m_hash
	the hash

std::string	m_str
	the actual string

Friends
std::string	operator+ (const std::string &lhs, const Gaudi::StringKey &rhs)

std::string	operator+ (const char *lhs, const Gaudi::StringKey &rhs)

std::string	operator+ (const Gaudi::StringKey &lhs, const std::string &rhs)

std::string	operator+ (const Gaudi::StringKey &lhs, const char *rhs)

Detailed Description

Helper class for efficient "key" access for strings.

Multiple lookups of the same key can be speed up by using a pre-computed key:

std::map<StringKey, double> m = {...};
const StringKey& key("SomeLongKey");
 
// EFFICIENT:
auto i1 = m.find ( key ) ;
 
// CAN BE VERY INEFICIENT:
auto i2 = m_find( "SomeLongKey" );

The class also supports heterogeneous lookups without the need to construct a temporary StringKey object:

std::unordered_set<Gaudi::StringKey, Gaudi::StringKeyHash, std::equal_to<>> s = {...};
 
s.contains("foo");

Attention: NEVER use the actual hash value for anything stored in files, as it is not guaranteed that the hashing scheme will remain the same.

Author: Vanya BELYAEV Ivan..nosp@m.Bely.nosp@m.aev@n.nosp@m.ikhe.nosp@m.f.nl; Gerhard Raven (based on stringKey); Frank Winklmeier

Date: 2009-04-08

Definition at line 66 of file StringKey.h.

Constructor & Destructor Documentation

◆ StringKey() [1/4]

Gaudi::StringKey::StringKey ( )

inline

Default constructor from empty string.

Definition at line 69 of file StringKey.h.

69: StringKey( std::string_view{} ) {}

Gaudi::StringKey::StringKey

StringKey()

Default constructor from empty string.

Definition StringKey.h:69

◆ StringKey() [2/4]

Gaudi::StringKey::StringKey ( const char * key )

inline

constructor from plain C-string, perform hashing

Definition at line 71 of file StringKey.h.

71: StringKey( std::string_view{ key } ) {}

ProduceConsume.key

key

Definition ProduceConsume.py:84

◆ StringKey() [3/4]

Gaudi::StringKey::StringKey ( std::string_view key )

inline

constructor from std::string_view, perform hashing

Definition at line 73 of file StringKey.h.

73: m_hash{ StringKeyHash()( key ) }, m_str( key ) {}

Gaudi::StringKey::m_str

std::string m_str

the actual string

Definition StringKey.h:140

Gaudi::StringKey::m_hash

std::size_t m_hash

the hash

Definition StringKey.h:137

◆ StringKey() [4/4]

Gaudi::StringKey::StringKey ( std::string key )

inline

constructor from std::string, perform hashing

Definition at line 75 of file StringKey.h.

75: m_hash{ StringKeyHash()( key ) }, m_str( std::move( key ) ) {}

Member Function Documentation

◆ eq() [1/2]

bool Gaudi::StringKey::__eq__ ( const StringKey & right ) const

equality operator for python

Definition at line 25 of file StringKey.cpp.

25{ return *this == right; }

◆ eq() [2/2]

bool Gaudi::StringKey::__eq__ ( std::string_view right ) const

equality operators for python

Definition at line 26 of file StringKey.cpp.

26{ return *this == right; }

◆ hash()

std::size_t Gaudi::StringKey::__hash__ ( ) const

inline

the actual access to the hash

Attention

NEVER use the actual hash value for anything stored in files, as it is not guaranteed that the hashing scheme will remain the same. The two reason for this function are:

transparent usage of this object for hashmap-like containers
Python @reutrn the actual hash value

Definition at line 107 of file StringKey.h.

107{ return m_hash; }

◆ neq() [1/2]

bool Gaudi::StringKey::__neq__ ( const std::string_view right ) const

non-equality operator for python

Definition at line 28 of file StringKey.cpp.

28{ return *this != right; }

◆ neq() [2/2]

bool Gaudi::StringKey::__neq__ ( const StringKey & right ) const

non-equality operator for python

Definition at line 27 of file StringKey.cpp.

27{ return *this != right; }

◆ repr()

std::string Gaudi::StringKey::__repr__ ( ) const

the representation of the object

Definition at line 24 of file StringKey.cpp.

24{ return toString(); }

Gaudi::StringKey::toString

std::string toString() const

string representation (for properties)

Definition StringKey.cpp:22

◆ str()

const std::string & Gaudi::StringKey::__str__ ( ) const

the representation of the object

Definition at line 23 of file StringKey.cpp.

23{ return m_str; }

◆ empty()

bool Gaudi::StringKey::empty ( ) const

inline

empty key?

Definition at line 84 of file StringKey.h.

84{ return m_str.empty(); }

◆ operator const std::string &()

Gaudi::StringKey::operator const std::string & ( ) const

inline

implicit cast to std::string

Definition at line 80 of file StringKey.h.

80{ return m_str; }

◆ operator std::string_view()

Gaudi::StringKey::operator std::string_view ( ) const

inline

implicit cast to std::string_view

Definition at line 82 of file StringKey.h.

82{ return m_str; }

◆ operator!()

bool Gaudi::StringKey::operator! ( ) const

inline

empty key?

Definition at line 86 of file StringKey.h.

86{ return empty(); }

Gaudi::StringKey::empty

bool empty() const

empty key?

Definition StringKey.h:84

◆ operator<=>()

auto Gaudi::StringKey::operator<=> ( const StringKey & ) const

default

Compiler generated spaceship operator first comparing hash, then string (see below)

◆ operator==() [1/4]

bool Gaudi::StringKey::operator== ( const char * rhs ) const

inline

Comparison to other string-like types.

Definition at line 94 of file StringKey.h.

94{ return m_str == rhs; }

◆ operator==() [2/4]

bool Gaudi::StringKey::operator== ( const std::string & rhs ) const

inline

Definition at line 96 of file StringKey.h.

96{ return m_str == rhs; }

◆ operator==() [3/4]

bool Gaudi::StringKey::operator== ( const StringKey & ) const

default

Compiler generated equality operator first comparing hash, then string (see below)

◆ operator==() [4/4]

bool Gaudi::StringKey::operator== ( std::string_view rhs ) const

inline

Definition at line 95 of file StringKey.h.

95{ return m_str == rhs; }

◆ str()

const std::string & Gaudi::StringKey::str ( ) const

inline

the actual string

Definition at line 78 of file StringKey.h.

78{ return m_str; }

◆ toString()

std::string Gaudi::StringKey::toString ( ) const

string representation (for properties)

Definition at line 22 of file StringKey.cpp.

22{ return Gaudi::Utils::toString( m_str ); }

Gaudi::Utils::toString

std::string toString(const TYPE &obj)

the generic implementation of the type conversion to the string

Definition ToStream.h:326

Friends And Related Symbol Documentation

◆ operator+ [1/4]

std::string operator+	(	const char *	lhs,
		const Gaudi::StringKey &	rhs )

friend

Definition at line 126 of file StringKey.h.

126{ return lhs + rhs.str(); }

Gaudi::StringKey::str

const std::string & str() const

the actual string

Definition StringKey.h:78

◆ operator+ [2/4]

std::string operator+	(	const Gaudi::StringKey &	lhs,
		const char *	rhs )

friend

Definition at line 128 of file StringKey.h.

128{ return lhs.str() + rhs; }

◆ operator+ [3/4]

std::string operator+	(	const Gaudi::StringKey &	lhs,
		const std::string &	rhs )

friend

Definition at line 127 of file StringKey.h.

127{ return lhs.str() + rhs; }

◆ operator+ [4/4]

std::string operator+	(	const std::string &	lhs,
		const Gaudi::StringKey &	rhs )

friend

Definition at line 125 of file StringKey.h.

125{ return lhs + rhs.str(); }

Member Data Documentation

◆ m_hash

std::size_t Gaudi::StringKey::m_hash

private

the hash

Definition at line 137 of file StringKey.h.

◆ m_str

std::string Gaudi::StringKey::m_str

private

the actual string

Definition at line 140 of file StringKey.h.

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

GaudiKernel/include/GaudiKernel/StringKey.h
GaudiKernel/src/Lib/StringKey.cpp

Public Member Functions

Private Attributes

Friends

Detailed Description

Constructor & Destructor Documentation

◆ StringKey() [1/4]

◆ StringKey() [2/4]

◆ StringKey() [3/4]

◆ StringKey() [4/4]

Member Function Documentation

◆ __eq__() [1/2]

◆ __eq__() [2/2]

◆ __hash__()

◆ __neq__() [1/2]

◆ __neq__() [2/2]

◆ __repr__()

◆ __str__()

◆ empty()

◆ operator const std::string &()

◆ operator std::string_view()

◆ operator!()

◆ operator<=>()

◆ operator==() [1/4]

◆ operator==() [2/4]

◆ operator==() [3/4]

◆ operator==() [4/4]

◆ str()

◆ toString()

Friends And Related Symbol Documentation

◆ operator+ [1/4]

◆ operator+ [2/4]

◆ operator+ [3/4]

◆ operator+ [4/4]

Member Data Documentation

◆ m_hash

◆ m_str

◆ eq() [1/2]

◆ eq() [2/2]

◆ hash()

◆ neq() [1/2]

◆ neq() [2/2]

◆ repr()

◆ str()