A Mask type used for constant-time operations. More...

#include <ct_utils.hpp>

Collaboration diagram for jau::CT::Mask< T, >:

Public Member Functions
	Mask (const Mask< T > &other) noexcept

template<typename U >
	Mask (Mask< U > o) noexcept
	Derive a Mask from a Mask of a larger type. More...

T	if_not_set_return (T x) const noexcept
	Return x if the mask is cleared, or otherwise zero. More...

T	if_set_return (T x) const noexcept
	Return x if the mask is set, or otherwise zero. More...

void	if_set_zero_out (T buf[], size_t elems) noexcept
	If this mask is set, zero out buf, otherwise do nothing. More...

bool	is_set () const noexcept
	Return true iff this mask is set. More...

Mask< T > &	operator&= (Mask< T > o) noexcept
	AND-combine two masks. More...

Mask< T > &	operator= (const Mask< T > &other) noexcept

Mask< T > &	operator^= (Mask< T > o) noexcept
	XOR-combine two masks. More...

Mask< T > &	operator\|= (Mask< T > o) noexcept
	OR-combine two masks. More...

Mask< T >	operator~ () const noexcept
	Negate this mask. More...

T	select (T x, T y) const noexcept
	If this mask is set, return x, otherwise return y. More...

T	select_and_unpoison (T x, T y) const noexcept

Mask< T >	select_mask (Mask< T > x, Mask< T > y) const noexcept
	If this mask is set, return x, otherwise return y. More...

void	select_n (T output[], const T x[], const T y[], size_t len) const noexcept
	Conditionally set output to x or y, depending on if mask is set or cleared (resp) More...

T	unpoisoned_value () const noexcept
	Return the value of the mask, unpoisoned. More...

T	value () const noexcept
	Return the underlying value of the mask. More...

Static Public Member Functions
static Mask< T >	cleared () noexcept
	Return a Mask<T> with all bits cleared. More...

template<typename U >
static Mask< T >	expand (Mask< U > m) noexcept
	Return a Mask<T> which is set if m is set. More...

static Mask< T >	expand (T v) noexcept
	Return a Mask<T> which is set if v is != 0. More...

static Mask< T >	is_any_of (T v, std::initializer_list< T > accepted) noexcept

static Mask< T >	is_equal (T x, T y) noexcept
	Return a Mask<T> which is set if x == y. More...

static Mask< T >	is_gt (T x, T y) noexcept
	Return a Mask<T> which is set if x > y. More...

static Mask< T >	is_gte (T x, T y) noexcept
	Return a Mask<T> which is set if x >= y. More...

static Mask< T >	is_lt (T x, T y) noexcept
	Return a Mask<T> which is set if x < y. More...

static Mask< T >	is_lte (T x, T y) noexcept
	Return a Mask<T> which is set if x <= y. More...

static Mask< T >	is_within_range (T v, T l, T u) noexcept

static Mask< T >	is_zero (T x) noexcept
	Return a Mask<T> which is set if v is == 0 or cleared otherwise. More...

static Mask< T >	set () noexcept
	Return a Mask<T> with all bits set. More...

Friends
Mask< T >	operator& (Mask< T > x, Mask< T > y) noexcept
	AND-combine two masks. More...

Mask< T >	operator^ (Mask< T > x, Mask< T > y) noexcept
	XOR-combine two masks. More...

Mask< T >	operator\| (Mask< T > x, Mask< T > y) noexcept
	OR-combine two masks. More...

Detailed Description

template<typename T, std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>
class jau::CT::Mask< T, >

A Mask type used for constant-time operations.

A Mask<T> always has value either 0 (all bits cleared) or ~0 (all bits set). All operations in a Mask<T> are intended to compile to code which does not contain conditional jumps. This must be verified with tooling (eg binary disassembly or using valgrind) since you never know what a compiler might do.

Template Parameters

T	unsigned integral type

Definition at line 80 of file ct_utils.hpp.

Constructor & Destructor Documentation

◆ Mask() [1/2]

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

jau::CT::Mask< T, >::Mask ( const Mask< T > & other )

inlinenoexcept

Definition at line 83 of file ct_utils.hpp.

◆ Mask() [2/2]

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

template<typename U >

jau::CT::Mask< T, >::Mask ( Mask< U > o )

inlinenoexcept

Derive a Mask from a Mask of a larger type.

Definition at line 95 of file ct_utils.hpp.

Member Function Documentation

◆ operator=()

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

Mask< T > & jau::CT::Mask< T, >::operator= ( const Mask< T > & other )

inlinenoexcept

Definition at line 86 of file ct_utils.hpp.

◆ set()

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

static Mask< T > jau::CT::Mask< T, >::set ( )

inlinestaticnoexcept

Return a Mask<T> with all bits set.

Definition at line 103 of file ct_utils.hpp.

◆ cleared()

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

static Mask< T > jau::CT::Mask< T, >::cleared ( )

inlinestaticnoexcept

Return a Mask<T> with all bits cleared.

Definition at line 111 of file ct_utils.hpp.

◆ expand() [1/2]

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

static Mask< T > jau::CT::Mask< T, >::expand ( T v )

inlinestaticnoexcept

Return a Mask<T> which is set if v is != 0.

Definition at line 119 of file ct_utils.hpp.

Here is the caller graph for this function:

◆ expand() [2/2]

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

template<typename U >

static Mask< T > jau::CT::Mask< T, >::expand ( Mask< U > m )

inlinestaticnoexcept

Return a Mask<T> which is set if m is set.

Definition at line 128 of file ct_utils.hpp.

◆ is_zero()

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

static Mask< T > jau::CT::Mask< T, >::is_zero ( T x )

inlinestaticnoexcept

Return a Mask<T> which is set if v is == 0 or cleared otherwise.

Definition at line 137 of file ct_utils.hpp.

Here is the caller graph for this function:

◆ is_equal()

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

static Mask< T > jau::CT::Mask< T, >::is_equal	(	T	x,
		T	y
	)

inlinestaticnoexcept

Return a Mask<T> which is set if x == y.

Definition at line 145 of file ct_utils.hpp.

Here is the caller graph for this function:

◆ is_lt()

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

static Mask< T > jau::CT::Mask< T, >::is_lt	(	T	x,
		T	y
	)

inlinestaticnoexcept

Return a Mask<T> which is set if x < y.

Definition at line 153 of file ct_utils.hpp.

Here is the caller graph for this function:

◆ is_gt()

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

static Mask< T > jau::CT::Mask< T, >::is_gt	(	T	x,
		T	y
	)

inlinestaticnoexcept

Return a Mask<T> which is set if x > y.

Definition at line 161 of file ct_utils.hpp.

◆ is_lte()

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

static Mask< T > jau::CT::Mask< T, >::is_lte	(	T	x,
		T	y
	)

inlinestaticnoexcept

Return a Mask<T> which is set if x <= y.

Definition at line 169 of file ct_utils.hpp.

◆ is_gte()

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

static Mask< T > jau::CT::Mask< T, >::is_gte	(	T	x,
		T	y
	)

inlinestaticnoexcept

Return a Mask<T> which is set if x >= y.

Definition at line 177 of file ct_utils.hpp.

◆ is_within_range()

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

static Mask< T > jau::CT::Mask< T, >::is_within_range	(	T	v,
		T	l,
		T	u
	)

inlinestaticnoexcept

Definition at line 182 of file ct_utils.hpp.

◆ is_any_of()

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

static Mask< T > jau::CT::Mask< T, >::is_any_of	(	T	v,
		std::initializer_list< T >	accepted
	)

inlinestaticnoexcept

Definition at line 192 of file ct_utils.hpp.

◆ operator&=()

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

Mask< T > & jau::CT::Mask< T, >::operator&= ( Mask< T > o )

inlinenoexcept

AND-combine two masks.

Definition at line 209 of file ct_utils.hpp.

◆ operator^=()

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

Mask< T > & jau::CT::Mask< T, >::operator^= ( Mask< T > o )

inlinenoexcept

XOR-combine two masks.

Definition at line 218 of file ct_utils.hpp.

◆ operator|=()

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

Mask< T > & jau::CT::Mask< T, >::operator|= ( Mask< T > o )

inlinenoexcept

OR-combine two masks.

Definition at line 227 of file ct_utils.hpp.

◆ operator~()

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

Mask< T > jau::CT::Mask< T, >::operator~ ( ) const

inlinenoexcept

Negate this mask.

Definition at line 260 of file ct_utils.hpp.

◆ if_set_return()

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

T jau::CT::Mask< T, >::if_set_return ( T x ) const

inlinenoexcept

Return x if the mask is set, or otherwise zero.

Definition at line 268 of file ct_utils.hpp.

◆ if_not_set_return()

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

T jau::CT::Mask< T, >::if_not_set_return ( T x ) const

inlinenoexcept

Return x if the mask is cleared, or otherwise zero.

Definition at line 276 of file ct_utils.hpp.

Here is the caller graph for this function:

◆ select()

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

T jau::CT::Mask< T, >::select	(	T	x,
		T	y
	)		const

inlinenoexcept

If this mask is set, return x, otherwise return y.

Definition at line 284 of file ct_utils.hpp.

Here is the caller graph for this function:

◆ select_and_unpoison()

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

T jau::CT::Mask< T, >::select_and_unpoison	(	T	x,
		T	y
	)		const

inlinenoexcept

Definition at line 289 of file ct_utils.hpp.

◆ select_mask()

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

Mask< T > jau::CT::Mask< T, >::select_mask	(	Mask< T >	x,
		Mask< T >	y
	)		const

inlinenoexcept

If this mask is set, return x, otherwise return y.

Definition at line 299 of file ct_utils.hpp.

◆ select_n()

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

void jau::CT::Mask< T, >::select_n	(	T	output[],
		const T	x[],
		const T	y[],
		size_t	len
	)		const

inlinenoexcept

Conditionally set output to x or y, depending on if mask is set or cleared (resp)

Definition at line 308 of file ct_utils.hpp.

◆ if_set_zero_out()

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

void jau::CT::Mask< T, >::if_set_zero_out	(	T	buf[],
		size_t	elems
	)

inlinenoexcept

If this mask is set, zero out buf, otherwise do nothing.

Definition at line 317 of file ct_utils.hpp.

◆ unpoisoned_value()

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

T jau::CT::Mask< T, >::unpoisoned_value ( ) const

inlinenoexcept

Return the value of the mask, unpoisoned.

Definition at line 328 of file ct_utils.hpp.

Here is the caller graph for this function:

◆ is_set()

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

bool jau::CT::Mask< T, >::is_set ( ) const

inlinenoexcept

Return true iff this mask is set.

Definition at line 338 of file ct_utils.hpp.

◆ value()

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

T jau::CT::Mask< T, >::value ( ) const

inlinenoexcept

Return the underlying value of the mask.

Definition at line 346 of file ct_utils.hpp.

Here is the caller graph for this function:

Friends And Related Function Documentation

◆ operator&

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

Mask< T > operator&	(	Mask< T >	x,
		Mask< T >	y
	)

friend

AND-combine two masks.

Definition at line 236 of file ct_utils.hpp.

◆ operator^

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

Mask< T > operator^	(	Mask< T >	x,
		Mask< T >	y
	)

friend

XOR-combine two masks.

Definition at line 244 of file ct_utils.hpp.

◆ operator|

template<typename T , std::enable_if_t< std::is_integral_v< T > &&std::is_unsigned_v< T >, bool > = true>

Mask< T > operator\|	(	Mask< T >	x,
		Mask< T >	y
	)

friend

OR-combine two masks.

Definition at line 252 of file ct_utils.hpp.

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

include/jau/ct_utils.hpp

Public Member Functions

Static Public Member Functions

Friends

Detailed Description

Constructor & Destructor Documentation

◆ Mask() [1/2]

◆ Mask() [2/2]

Member Function Documentation

◆ operator=()

◆ set()

◆ cleared()

◆ expand() [1/2]

◆ expand() [2/2]

◆ is_zero()

◆ is_equal()

◆ is_lt()

◆ is_gt()

◆ is_lte()

◆ is_gte()

◆ is_within_range()

◆ is_any_of()

◆ operator&=()

◆ operator^=()

◆ operator|=()

◆ operator~()

◆ if_set_return()

◆ if_not_set_return()

◆ select()

◆ select_and_unpoison()

◆ select_mask()

◆ select_n()

◆ if_set_zero_out()

◆ unpoisoned_value()

◆ is_set()

◆ value()

Friends And Related Function Documentation

◆ operator&

◆ operator^

◆ operator|