qhashfunctions.h File Reference

(53cc504345c80dba6876a8a1fd8aa604547c9b07)

#include <QtCore/qstring.h>
#include <QtCore/qstringfwd.h>
#include <QtCore/qbitarray.h>
#include <numeric>
#include <functional>
#include <optional>

Include dependency graph for qhashfunctions.h:

This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Classes
class	QHashSeed
	\inmodule QtCore More...
struct	QHashHeterogeneousSearch< Key, T >
struct	QHashHeterogeneousSearch< QString, QStringView >
struct	QHashHeterogeneousSearch< QStringView, QString >
struct	QHashHeterogeneousSearch< QByteArray, QByteArrayView >
struct	QHashHeterogeneousSearch< QByteArrayView, QByteArray >
struct	QHashHeterogeneousSearch< QString, QLatin1StringView >
struct	QHashHeterogeneousSearch< QStringView, QLatin1StringView >
struct	QHashHeterogeneousSearch< QLatin1StringView, QString >
struct	QHashHeterogeneousSearch< QLatin1StringView, QStringView >
struct	QHashPrivate::detail::is_equality_comparable_with< T, U, typename >
struct	QHashPrivate::detail::is_equality_comparable_with< T, U, std::void_t< decltype(bool(std::declval< T >()==std::declval< U >())), decltype(bool(std::declval< U >()==std::declval< T >())), decltype(bool(std::declval< T >() !=std::declval< U >())), decltype(bool(std::declval< U >() !=std::declval< T >())) > >
struct	QHashPrivate::HeterogeneouslySearchableWithHelper< Key, T >
struct	QtPrivate::QHashCombinerWithSeed< Mixer >
struct	QtPrivate::QHashCombineMixer
struct	QtPrivate::QHashCombineCommutativeMixer
struct	QtPrivate::QNothrowHashable< T, Enable >
struct	QtPrivate::QNothrowHashable< T, std::enable_if_t< QNothrowHashableHelper_v< T > > >

Namespaces
namespace	QHashPrivate
namespace	QHashPrivate::detail
namespace	QtPrivate

Macros
#define	QT_MK_QHASH_COMPAT(X)
#define	QT_SPECIALIZE_STD_HASH_TO_CALL_QHASH(Class, Arguments)
#define	QT_SPECIALIZE_STD_HASH_TO_CALL_QHASH_BY_CREF(Class)
#define	QT_SPECIALIZE_STD_HASH_TO_CALL_QHASH_BY_VALUE(Class)

Typedefs
template<typename Key, typename T>
using	QHashPrivate::HeterogeneouslySearchableWith
template<typename Key, typename K>
using	QHashPrivate::if_heterogeneously_searchable_with
template<typename Mixer>
using	QtPrivate::QHashCombiner = QHashCombinerWithSeed<Mixer>
using	QtPrivate::QHashCombine = QHashCombiner<QHashCombineMixer>
using	QtPrivate::QHashCombineWithSeed = QHashCombinerWithSeed<QHashCombineMixer>
using	QtPrivate::QHashCombineCommutative = QHashCombiner<QHashCombineCommutativeMixer>
using	QtPrivate::QHashCombineCommutativeWithSeed = QHashCombinerWithSeed<QHashCombineCommutativeMixer>
template<typename... T>
using	QtPrivate::QHashMultiReturnType

Functions
Q_DECL_CONST_FUNCTION constexpr size_t	QHashPrivate::hash (size_t key, size_t seed) noexcept
template<typename T1, typename T2>
constexpr bool	QHashPrivate::noexceptPairHash ()
Q_CORE_EXPORT Q_DECL_PURE_FUNCTION size_t	qHashBits (const void *p, size_t size, size_t seed=0) noexcept
template<typename T1, typename T2>
size_t	qHash (const std::pair< T1, T2 > &key, size_t seed=0) noexcept(QHashPrivate::noexceptPairHash< T1, T2 >())
constexpr size_t	qHash (std::nullopt_t, size_t seed=0) noexcept
template<typename T>
constexpr size_t	qHash (const std::optional< T > &key, size_t seed=0) noexcept(QHashPrivate::noexceptPairHash< T, T >())
Q_DECL_CONST_FUNCTION constexpr size_t	qHash (char key, size_t seed=0) noexcept
Q_DECL_CONST_FUNCTION constexpr size_t	qHash (uchar key, size_t seed=0) noexcept
Q_DECL_CONST_FUNCTION constexpr size_t	qHash (signed char key, size_t seed=0) noexcept
Q_DECL_CONST_FUNCTION constexpr size_t	qHash (ushort key, size_t seed=0) noexcept
Q_DECL_CONST_FUNCTION constexpr size_t	qHash (short key, size_t seed=0) noexcept
Q_DECL_CONST_FUNCTION constexpr size_t	qHash (uint key, size_t seed=0) noexcept
Q_DECL_CONST_FUNCTION constexpr size_t	qHash (int key, size_t seed=0) noexcept
Q_DECL_CONST_FUNCTION constexpr size_t	qHash (ulong key, size_t seed=0) noexcept
Q_DECL_CONST_FUNCTION constexpr size_t	qHash (long key, size_t seed=0) noexcept
Q_DECL_CONST_FUNCTION constexpr size_t	qHash (quint64 key, size_t seed=0) noexcept
Q_DECL_CONST_FUNCTION constexpr size_t	qHash (qint64 key, size_t seed=0) noexcept
Q_DECL_CONST_FUNCTION size_t	qHash (float key, size_t seed=0) noexcept
Q_CORE_EXPORT Q_DECL_CONST_FUNCTION size_t	qHash (double key, size_t seed=0) noexcept
Q_CORE_EXPORT Q_DECL_CONST_FUNCTION size_t	qHash (long double key, size_t seed=0) noexcept
Q_DECL_CONST_FUNCTION constexpr size_t	qHash (wchar_t key, size_t seed=0) noexcept
Q_DECL_CONST_FUNCTION constexpr size_t	qHash (char16_t key, size_t seed=0) noexcept
Q_DECL_CONST_FUNCTION constexpr size_t	qHash (char32_t key, size_t seed=0) noexcept
template<class T>
size_t	qHash (const T *key, size_t seed=0) noexcept
Q_DECL_CONST_FUNCTION constexpr size_t	qHash (std::nullptr_t, size_t seed=0) noexcept
template<class Enum, std::enable_if_t< std::is_enum_v< Enum >, bool > = true>
Q_DECL_CONST_FUNCTION constexpr size_t	qHash (Enum e, size_t seed=0) noexcept
Q_DECL_CONST_FUNCTION constexpr size_t	qHash (const QChar key, size_t seed=0) noexcept
Q_CORE_EXPORT Q_DECL_PURE_FUNCTION size_t	qHash (QByteArrayView key, size_t seed=0) noexcept
Q_DECL_PURE_FUNCTION size_t	qHash (const QByteArray &key, size_t seed=0 QT6_DECL_NEW_OVERLOAD_TAIL) noexcept
Q_CORE_EXPORT Q_DECL_PURE_FUNCTION size_t	qHash (QStringView key, size_t seed=0) noexcept
Q_DECL_PURE_FUNCTION size_t	qHash (const QString &key, size_t seed=0) noexcept
Q_CORE_EXPORT Q_DECL_PURE_FUNCTION size_t	qHash (const QBitArray &key, size_t seed=0)
Q_CORE_EXPORT Q_DECL_PURE_FUNCTION size_t	qHash (QLatin1StringView key, size_t seed=0) noexcept
Q_DECL_CONST_FUNCTION constexpr size_t	qHash (QKeyCombination key, size_t seed=0) noexcept
Q_CORE_EXPORT Q_DECL_PURE_FUNCTION uint	qt_hash (QStringView key, uint chained=0) noexcept
template<typename Enum>
Q_DECL_CONST_FUNCTION constexpr size_t	qHash (QFlags< Enum > flags, size_t seed=0) noexcept
template<typename T>
constexpr size_t	QHashPrivate::ex1to2arg (const T &key, size_t seed)
template<typename T>
bool	qHashEquals (const T &a, const T &b)
template<typename T1, typename T2, QHashPrivate::if_heterogeneously_searchable_with< T1, T2 > = true>
bool	qHashEquals (const T1 &a, const T2 &b)
template<typename... T>
constexpr QtPrivate::QHashMultiReturnType< T... >	qHashMulti (size_t seed, const T &... args) noexcept(std::conjunction_v< QtPrivate::QNothrowHashable< T >... >)
template<typename... T>
constexpr QtPrivate::QHashMultiReturnType< T... >	qHashMultiCommutative (size_t seed, const T &... args) noexcept(std::conjunction_v< QtPrivate::QNothrowHashable< T >... >)
template<typename InputIterator>
size_t	qHashRange (InputIterator first, InputIterator last, size_t seed=0) noexcept(noexcept(qHash(*first, 0)))
template<typename InputIterator>
size_t	qHashRangeCommutative (InputIterator first, InputIterator last, size_t seed=0) noexcept(noexcept(qHash(*first, 0)))

Variables
template<typename T>
constexpr bool	QtPrivate::QNothrowHashableHelper_v = noexcept(qHash(std::declval<const T &>(), size_t(0)))
template<typename T>
constexpr bool	QtPrivate::QNothrowHashable_v = QNothrowHashable<T>::value

Macro Definition Documentation

QT_MK_QHASH_COMPAT

#define QT_MK_QHASH_COMPAT

(

X

)

Value:

template <typename T, std::enable_if_t<std::is_same_v<T, X>, bool> = true> \
constexpr size_t qHash(T key, size_t seed = 0) noexcept \
/* QHashPrivate::hash() xors before mixing, while 1-to-2-arg adapter xors after */ \
{ return QHashPrivate::hash(size_t(key), 0 QT7_ONLY(+ seed)) QT6_ONLY(^ seed); } \
/* end */

Definition at line 103 of file qhashfunctions.h.

QT_SPECIALIZE_STD_HASH_TO_CALL_QHASH

#define QT_SPECIALIZE_STD_HASH_TO_CALL_QHASH	(		Class,
			Arguments )

Value:

QT_BEGIN_INCLUDE_NAMESPACE                                      \
namespace std {                                                 \
    template <>                                                 \
    struct hash< QT_PREPEND_NAMESPACE(Class) > {                \
        using argument_type = QT_PREPEND_NAMESPACE(Class);      \
        using result_type = size_t;                             \
        size_t operator()(Arguments s) const                    \
          noexcept(QT_PREPEND_NAMESPACE(                        \
                 QtPrivate::QNothrowHashable_v)<argument_type>) \
        {                                                       \
            /* this seeds qHash with the result of */           \
            /* std::hash applied to an int, to reap */          \
            /* any protection against predictable hash */       \
            /* values the std implementation may provide */     \
            using QT_PREPEND_NAMESPACE(qHash);                  \
            return qHash(s, qHash(std::hash<int>{}(0)));        \
        }                                                       \
    };                                                          \
}                                                               \
QT_END_INCLUDE_NAMESPACE                                        \
/*end*/

Definition at line 484 of file qhashfunctions.h.

QT_SPECIALIZE_STD_HASH_TO_CALL_QHASH_BY_CREF

#define QT_SPECIALIZE_STD_HASH_TO_CALL_QHASH_BY_CREF

(

Class

)

Value:

QT_SPECIALIZE_STD_HASH_TO_CALL_QHASH(Class, const argument_type &)

Definition at line 507 of file qhashfunctions.h.

QT_SPECIALIZE_STD_HASH_TO_CALL_QHASH_BY_VALUE

#define QT_SPECIALIZE_STD_HASH_TO_CALL_QHASH_BY_VALUE

(

Class

)

Value:

QT_SPECIALIZE_STD_HASH_TO_CALL_QHASH(Class, argument_type)

Definition at line 509 of file qhashfunctions.h.

Function Documentation

qHash() [1/32]

Q_DECL_CONST_FUNCTION constexpr size_t qHash ( char key, size_t seed = 0 )

inlineconstexprnoexcept

Since

5.0 \qhashbuiltin

Definition at line 110 of file qhashfunctions.h.

qHash() [2/32]

Q_DECL_CONST_FUNCTION constexpr size_t qHash ( char16_t key, size_t seed = 0 )

inlineconstexprnoexcept

Since

6.0 \qhashbuiltin

Definition at line 180 of file qhashfunctions.h.

qHash() [3/32]

Q_DECL_CONST_FUNCTION constexpr size_t qHash ( char32_t key, size_t seed = 0 )

inlineconstexprnoexcept

Since

6.0 \qhashbuiltin

Definition at line 182 of file qhashfunctions.h.

qHash() [4/32]

size_t qHash ( const QBitArray & key, size_t seed = 0 )

noexcept

Since

5.0 \qhashold{QHash}

Definition at line 887 of file qhash.cpp.

qHash() [5/32]

Q_DECL_PURE_FUNCTION size_t qHash ( const QByteArray & key, size_t seed = 0 QT6_DECL_NEW_OVERLOAD_TAIL )

inlinenoexcept

Since

5.0 \qhashold{QHash}

Definition at line 217 of file qhashfunctions.h.

qHash() [6/32]

Q_DECL_CONST_FUNCTION constexpr size_t qHash ( const QChar key, size_t seed = 0 )

inlineconstexprnoexcept

Since

5.0 \qhashold{QHash}

Definition at line 210 of file qhashfunctions.h.

qHash() [7/32]

Q_DECL_PURE_FUNCTION size_t qHash ( const QString & key, size_t seed = 0 )

inlinenoexcept

Since

5.0 \qhashold{QHash}

Definition at line 223 of file qhashfunctions.h.

qHash() [8/32]

template<typename T>

size_t qHash ( const std::optional< T > & key, size_t seed = 0 )

constexprnoexcept

Since

6.12 \qhashbuiltinT{T}

This is equivalent to

key ? qHash(*key, seed) : qHash(std::nullopt, seed);

In particular, if key is engaged ({has_value()}), the hash value of key is guaranteed to be the same as that of {key.value()}, and all disengaged ({!has_value()}) optionals, of any type, hash to the same value.

See also

qHash(std::nullopt_t, size_t)

Definition at line 472 of file qhashfunctions.h.

qHash() [9/32]

template<typename T1, typename T2>

size_t qHash ( const std::pair< T1, T2 > & key, size_t seed = 0 )

inlinenoexcept

Since

5.7 \qhashbuiltinTS{T1}{T2}

Definition at line 478 of file qhashfunctions.h.

qHash() [10/32]

template<class T>

size_t qHash ( const T * key, size_t seed = 0 )

inlinenoexcept

Since

5.0 \qhashbuiltin

Definition at line 188 of file qhashfunctions.h.

qHash() [11/32]

size_t qHash ( double key, size_t seed )

noexcept

Since

5.3 \qhashbuiltin

Definition at line 1382 of file qhash.cpp.

qHash() [12/32]

template<class Enum, std::enable_if_t< std::is_enum_v< Enum >, bool > = true>

Q_DECL_CONST_FUNCTION constexpr size_t qHash ( Enum key, size_t seed = 0 )

inlineconstexprnoexcept

Since

6.5 \qhashbuiltin

Note

Prior to Qt 6.5, unscoped enums relied on the integer overloads of this function due to implicit conversion to their underlying integer types. For scoped enums, you had to implement an overload yourself. This is still the backwards-compatible fix to remain compatible with older Qt versions.

Definition at line 206 of file qhashfunctions.h.

qHash() [13/32]

Q_DECL_CONST_FUNCTION size_t qHash ( float key, size_t seed = 0 )

inlinenoexcept

Since

5.3 \qhashbuiltin

Definition at line 168 of file qhashfunctions.h.

qHash() [14/32]

Q_DECL_CONST_FUNCTION constexpr size_t qHash ( int key, size_t seed = 0 )

inlineconstexprnoexcept

Since

5.0 \qhashbuiltin

Definition at line 122 of file qhashfunctions.h.

qHash() [15/32]

size_t qHash ( long double key, size_t seed )

noexcept

Since

5.3 \qhashbuiltin

Definition at line 1399 of file qhash.cpp.

qHash() [16/32]

Q_DECL_CONST_FUNCTION constexpr size_t qHash ( long key, size_t seed = 0 )

inlineconstexprnoexcept

Since

5.0 \qhashbuiltin

Definition at line 126 of file qhashfunctions.h.

qHash() [17/32]

size_t qHash ( QByteArrayView key, size_t seed = 0 )

noexcept

Since

6.0 \qhashold{QHash}

Definition at line 876 of file qhash.cpp.

qHash() [18/32]

template<typename Enum>

Q_DECL_CONST_FUNCTION constexpr size_t qHash ( QFlags< Enum > flags, size_t seed = 0 )

inlineconstexprnoexcept

Definition at line 234 of file qhashfunctions.h.

qHash() [19/32]

Q_DECL_CONST_FUNCTION constexpr size_t qHash ( qint64 key, size_t seed = 0 )

inlineconstexprnoexcept

Since

5.0 \qhashbuiltin

Definition at line 135 of file qhashfunctions.h.

qHash() [20/32]

Q_DECL_CONST_FUNCTION constexpr size_t qHash ( QKeyCombination key, size_t seed = 0 )

inlineconstexprnoexcept

Definition at line 229 of file qhashfunctions.h.

qHash() [21/32]

size_t qHash ( QLatin1StringView key, size_t seed = 0 )

noexcept

Since

5.0 \qhashold{QHash}

Definition at line 901 of file qhash.cpp.

qHash() [22/32]

size_t qHash ( QStringView key, size_t seed = 0 )

noexcept

Since

5.10 \qhashold{QStringView}

Definition at line 881 of file qhash.cpp.

qHash() [23/32]

Q_DECL_CONST_FUNCTION constexpr size_t qHash ( quint64 key, size_t seed = 0 )

inlineconstexprnoexcept

Since

5.0 \qhashbuiltin

Definition at line 129 of file qhashfunctions.h.

qHash() [24/32]

Q_DECL_CONST_FUNCTION constexpr size_t qHash ( short key, size_t seed = 0 )

inlineconstexprnoexcept

Since

5.0 \qhashbuiltin

Definition at line 118 of file qhashfunctions.h.

qHash() [25/32]

Q_DECL_CONST_FUNCTION constexpr size_t qHash ( signed char key, size_t seed = 0 )

inlineconstexprnoexcept

Since

5.0 \qhashbuiltin

Definition at line 114 of file qhashfunctions.h.

qHash() [26/32]

size_t qHash ( std::nullopt_t key, size_t seed = 0 )

constexprnoexcept

Since

6.12 \qhashbuiltin

See also

qHash(const std::optional<T> &, size_t)

Definition at line 462 of file qhashfunctions.h.

qHash() [27/32]

Q_DECL_CONST_FUNCTION constexpr size_t qHash ( std::nullptr_t key, size_t seed = 0 )

inlineconstexprnoexcept

Since

6.0 \qhashbuiltin

Definition at line 201 of file qhashfunctions.h.

qHash() [28/32]

Q_DECL_CONST_FUNCTION constexpr size_t qHash ( uchar key, size_t seed = 0 )

inlineconstexprnoexcept

Since

5.0 \qhashbuiltin

Definition at line 112 of file qhashfunctions.h.

qHash() [29/32]

Q_DECL_CONST_FUNCTION constexpr size_t qHash ( uint key, size_t seed = 0 )

inlineconstexprnoexcept

Since

5.0 \qhashbuiltin

Definition at line 120 of file qhashfunctions.h.

qHash() [30/32]

Q_DECL_CONST_FUNCTION constexpr size_t qHash ( ulong key, size_t seed = 0 )

inlineconstexprnoexcept

Since

5.0 \qhashbuiltin

Definition at line 124 of file qhashfunctions.h.

qHash() [31/32]

Q_DECL_CONST_FUNCTION constexpr size_t qHash ( ushort key, size_t seed = 0 )

inlineconstexprnoexcept

Since

5.0 \qhashbuiltin

Definition at line 116 of file qhashfunctions.h.

qHash() [32/32]

Q_DECL_CONST_FUNCTION constexpr size_t qHash ( wchar_t key, size_t seed = 0 )

inlineconstexprnoexcept

Since

6.0 \qhashbuiltin

Definition at line 178 of file qhashfunctions.h.

qHashBits()

size_t qHashBits ( const void * p, size_t size, size_t seed = 0 )

related

Definition at line 851 of file qhash.cpp.

qHashEquals() [1/2]

template<typename T>

bool qHashEquals ( const T & a, const T & b )

related

Definition at line 315 of file qhashfunctions.h.

qHashEquals() [2/2]

template<typename T1, typename T2, QHashPrivate::if_heterogeneously_searchable_with< T1, T2 > = true>

bool qHashEquals	(	const T1 &	a,
		const T2 &	b )

Definition at line 321 of file qhashfunctions.h.

qHashMulti()

template<typename... T>

QtPrivate::QHashMultiReturnType< T... > qHashMulti ( size_t seed, const T &... args )

related

Definition at line 419 of file qhashfunctions.h.

qHashMultiCommutative()

template<typename... T>

QtPrivate::QHashMultiReturnType< T... > qHashMultiCommutative ( size_t seed, const T &... args )

related

Definition at line 433 of file qhashfunctions.h.

qHashRange()

template<typename InputIterator>

size_t qHashRange ( InputIterator first, InputIterator last, size_t seed = 0 )

related

Definition at line 441 of file qhashfunctions.h.

qHashRangeCommutative()

template<typename InputIterator>

size_t qHashRangeCommutative ( InputIterator first, InputIterator last, size_t seed = 0 )

related

Definition at line 448 of file qhashfunctions.h.

qt_hash()

uint qt_hash ( QStringView key, uint chained )

noexcept

Private copy of the implementation of the Qt 4 qHash algorithm for strings, (that is, QChar-based arrays, so all QString-like classes), to be used wherever the result is somehow stored or reused across multiple Qt versions. The public qHash implementation can change at any time, therefore one must not rely on the fact that it will always give the same results.

The qt_hash functions must never change their results.

This function can hash discontiguous memory by invoking it on each chunk, passing the previous's result in the next call's chained argument.

Definition at line 1087 of file qhash.cpp.