Data structure storing a fee and size, ordered by increasing fee/size. More...

#include <feefrac.h>

Inheritance diagram for FeeFrac:

Public Member Functions
constexpr	FeeFrac () noexcept
	Construct an IsEmpty() FeeFrac. More...

constexpr	FeeFrac (int64_t f, int32_t s) noexcept
	Construct a FeeFrac with specified fee and size. More...

constexpr	FeeFrac (const FeeFrac &) noexcept=default

constexpr FeeFrac &	operator= (const FeeFrac &) noexcept=default

bool	IsEmpty () const noexcept
	Check if this is empty (size and fee are 0). More...

void	operator+= (const FeeFrac &other) noexcept
	Add fee and size of another FeeFrac to this one. More...

void	operator-= (const FeeFrac &other) noexcept
	Subtract fee and size of another FeeFrac from this one. More...

template<bool RoundDown>
int64_t	EvaluateFee (int32_t at_size) const noexcept
	Compute the fee for a given size `at_size` using this object's feerate. More...

int64_t	EvaluateFeeDown (int32_t at_size) const noexcept
	Compute the fee for a given size `at_size` using this object's feerate, rounding down. More...

int64_t	EvaluateFeeUp (int32_t at_size) const noexcept
	Compute the fee for a given size `at_size` using this object's feerate, rounding up. More...

Static Public Member Functions
static std::pair< int64_t, uint32_t >	MulFallback (int64_t a, int32_t b) noexcept
	Helper function for 32*64 signed multiplication, returning an unspecified but totally ordered type. More...

static int64_t	DivFallback (std::pair< int64_t, uint32_t > n, int32_t d, bool round_down) noexcept
	Helper function for 96/32 signed division, rounding towards negative infinity (if round_down) or positive infinity (if !round_down). More...

Public Attributes
int64_t	fee

int32_t	size

Static Public Attributes
static constexpr auto	Mul = MulFallback

static constexpr auto	Div = DivFallback

Friends
FeeFrac	operator+ (const FeeFrac &a, const FeeFrac &b) noexcept
	Sum fee and size. More...

FeeFrac	operator- (const FeeFrac &a, const FeeFrac &b) noexcept
	Subtract both fee and size. More...

bool	operator== (const FeeFrac &a, const FeeFrac &b) noexcept
	Check if two FeeFrac objects are equal (both same fee and same size). More...

std::weak_ordering	FeeRateCompare (const FeeFrac &a, const FeeFrac &b) noexcept
	Compare two FeeFracs just by feerate. More...

bool	operator<< (const FeeFrac &a, const FeeFrac &b) noexcept
	Check if a FeeFrac object has strictly lower feerate than another. More...

bool	operator>> (const FeeFrac &a, const FeeFrac &b) noexcept
	Check if a FeeFrac object has strictly higher feerate than another. More...

std::strong_ordering	operator<=> (const FeeFrac &a, const FeeFrac &b) noexcept
	Compare two FeeFracs. More...

void	swap (FeeFrac &a, FeeFrac &b) noexcept
	Swap two FeeFracs. More...

Detailed Description

Data structure storing a fee and size, ordered by increasing fee/size.

The size of a FeeFrac cannot be zero unless the fee is also zero.

FeeFracs have a total ordering, first by increasing feerate (ratio of fee over size), and then by decreasing size. The empty FeeFrac (fee and size both 0) sorts last. So for example, the following FeeFracs are in sorted order:

fee=0 size=1 (feerate 0)
fee=1 size=2 (feerate 0.5)
fee=2 size=3 (feerate 0.667...)
fee=2 size=2 (feerate 1)
fee=1 size=1 (feerate 1)
fee=3 size=2 (feerate 1.5)
fee=2 size=1 (feerate 2)
fee=0 size=0 (undefined feerate)

A FeeFrac is considered "better" if it sorts after another, by this ordering. All standard comparison operators (<=>, ==, !=, >, <, >=, <=) respect this ordering.

The FeeRateCompare, and >> and << operators only compare feerate and treat equal feerate but different size as equivalent. The empty FeeFrac is neither lower or higher in feerate than any other.

Definition at line 38 of file feefrac.h.

Constructor & Destructor Documentation

◆ FeeFrac() [1/3]

constexpr FeeFrac::FeeFrac ( )

inlineconstexprnoexcept

Construct an IsEmpty() FeeFrac.

Definition at line 110 of file feefrac.h.

◆ FeeFrac() [2/3]

constexpr FeeFrac::FeeFrac	(	int64_t	f,
		int32_t	s
	)

inlineconstexprnoexcept

Construct a FeeFrac with specified fee and size.

Definition at line 113 of file feefrac.h.

◆ FeeFrac() [3/3]

constexpr FeeFrac::FeeFrac ( const FeeFrac & )

inlineconstexprdefaultnoexcept

Member Function Documentation

◆ DivFallback()

static int64_t FeeFrac::DivFallback	(	std::pair< int64_t, uint32_t >	n,
		int32_t	d,
		bool	round_down
	)

inlinestaticnoexcept

Helper function for 96/32 signed division, rounding towards negative infinity (if round_down) or positive infinity (if !round_down).

This is a fallback version, separate so that it can be tested on platforms where it isn't actually needed.

The exact behavior with negative n does not really matter, but this implementation chooses to be consistent for testability reasons.

The result must fit in an int64_t, and d must be strictly positive.

Definition at line 58 of file feefrac.h.

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◆ EvaluateFee()

template<bool RoundDown>

int64_t FeeFrac::EvaluateFee ( int32_t at_size ) const

inlinenoexcept

Compute the fee for a given size at_size using this object's feerate.

This effectively corresponds to evaluating (this->fee * at_size) / this->size, with the result rounded towards negative infinity (if RoundDown) or towards positive infinity (if !RoundDown).

Requires this->size > 0, at_size >= 0, and that the correct result fits in a int64_t. This is guaranteed to be the case when 0 <= at_size <= this->size.

Definition at line 201 of file feefrac.h.

◆ EvaluateFeeDown()

int64_t FeeFrac::EvaluateFeeDown ( int32_t at_size ) const

inlinenoexcept

Compute the fee for a given size at_size using this object's feerate, rounding down.

Definition at line 220 of file feefrac.h.

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◆ EvaluateFeeUp()

int64_t FeeFrac::EvaluateFeeUp ( int32_t at_size ) const

inlinenoexcept

Compute the fee for a given size at_size using this object's feerate, rounding up.

Definition at line 222 of file feefrac.h.

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◆ IsEmpty()

bool FeeFrac::IsEmpty ( ) const

inlinenoexcept

Check if this is empty (size and fee are 0).

Definition at line 119 of file feefrac.h.

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◆ MulFallback()

static std::pair< int64_t, uint32_t > FeeFrac::MulFallback	(	int64_t	a,
		int32_t	b
	)

inlinestaticnoexcept

Helper function for 32*64 signed multiplication, returning an unspecified but totally ordered type.

This is a fallback version, separate so it can be tested on platforms where it isn't actually needed.

Definition at line 43 of file feefrac.h.

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◆ operator+=()

void FeeFrac::operator+= ( const FeeFrac & other )

inlinenoexcept

Add fee and size of another FeeFrac to this one.

Definition at line 124 of file feefrac.h.

◆ operator-=()

void FeeFrac::operator-= ( const FeeFrac & other )

inlinenoexcept

Subtract fee and size of another FeeFrac from this one.

Definition at line 131 of file feefrac.h.

◆ operator=()

constexpr FeeFrac & FeeFrac::operator= ( const FeeFrac & )

inlineconstexprdefaultnoexcept

Friends And Related Function Documentation

◆ FeeRateCompare

std::weak_ordering FeeRateCompare	(	const FeeFrac &	a,
		const FeeFrac &	b
	)

friend

Compare two FeeFracs just by feerate.

Definition at line 156 of file feefrac.h.

◆ operator+

FeeFrac operator+	(	const FeeFrac &	a,
		const FeeFrac &	b
	)

friend

Sum fee and size.

Definition at line 138 of file feefrac.h.

◆ operator-

FeeFrac operator-	(	const FeeFrac &	a,
		const FeeFrac &	b
	)

friend

Subtract both fee and size.

Definition at line 144 of file feefrac.h.

◆ operator<<

bool operator<<	(	const FeeFrac &	a,
		const FeeFrac &	b
	)

friend

Check if a FeeFrac object has strictly lower feerate than another.

Definition at line 163 of file feefrac.h.

◆ operator<=>

std::strong_ordering operator<=>	(	const FeeFrac &	a,
		const FeeFrac &	b
	)

friend

Compare two FeeFracs.

<, >, <=, and >= are auto-generated from this.

Definition at line 177 of file feefrac.h.

◆ operator==

bool operator==	(	const FeeFrac &	a,
		const FeeFrac &	b
	)

friend

Check if two FeeFrac objects are equal (both same fee and same size).

Definition at line 150 of file feefrac.h.

◆ operator>>

bool operator>>	(	const FeeFrac &	a,
		const FeeFrac &	b
	)

friend

Check if a FeeFrac object has strictly higher feerate than another.

Definition at line 170 of file feefrac.h.

◆ swap

void swap	(	FeeFrac &	a,
		FeeFrac &	b
	)

friend

Swap two FeeFracs.

Definition at line 185 of file feefrac.h.

Member Data Documentation

◆ Div

constexpr auto FeeFrac::Div = DivFallback

staticconstexpr

Definition at line 103 of file feefrac.h.

◆ fee

int64_t FeeFrac::fee

Definition at line 106 of file feefrac.h.

◆ Mul

constexpr auto FeeFrac::Mul = MulFallback

staticconstexpr

Definition at line 102 of file feefrac.h.

◆ size

int32_t FeeFrac::size

Definition at line 107 of file feefrac.h.

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

src/util/feefrac.h

Public Member Functions

Static Public Member Functions

Public Attributes

Static Public Attributes

Friends

Detailed Description

Constructor & Destructor Documentation

◆ FeeFrac() [1/3]

◆ FeeFrac() [2/3]

◆ FeeFrac() [3/3]

Member Function Documentation

◆ DivFallback()

◆ EvaluateFee()

◆ EvaluateFeeDown()

◆ EvaluateFeeUp()

◆ IsEmpty()

◆ MulFallback()

◆ operator+=()

◆ operator-=()

◆ operator=()

Friends And Related Function Documentation

◆ FeeRateCompare

◆ operator+

◆ operator-

◆ operator<<

◆ operator<=>

◆ operator==

◆ operator>>

◆ swap

Member Data Documentation

◆ Div

◆ fee

◆ Mul

◆ size