SquidMath.h File Reference

#include "base/forward.h"
#include "base/TypeTraits.h"
#include <limits>
#include <optional>

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Namespaces
namespace	Math

Typedefs
template<typename T , typename U >
using	AllUnsigned = typename std::conditional< std::is_unsigned< T >::value &&std::is_unsigned< U >::value, std::true_type, std::false_type >::type

Functions
int	Math::intPercent (const int a, const int b)
int64_t	Math::int64Percent (const int64_t a, const int64_t b)
double	Math::doublePercent (const double, const double)
int	Math::intAverage (const int, const int, int, const int)
double	Math::doubleAverage (const double, const double, int, const int)
template<typename A , typename B >
constexpr bool	Less (const A a, const B b)
	whether integer a is less than integer b, with correct overflow handling
template<typename T >
constexpr void	AssertNaturalType ()
	ensure that T is supported by NaturalSum() and friends
template<typename S , typename A , typename B , std::enable_if_t< AllUnsigned< A, B >::value, int > = 0>
std::optional< S >	IncreaseSumInternal (const A a, const B b)
template<typename S , typename A , typename B , std::enable_if_t<!AllUnsigned< A, B >::value, int > = 0>
std::optional< S > constexpr	IncreaseSumInternal (const A a, const B b)
template<typename S , typename T >
std::optional< S >	IncreaseSum (const S s, const T t)
	argument pack expansion termination for IncreaseSum<S, T, Args...>()
template<typename S , typename T , typename... Args>
std::optional< S >	IncreaseSum (const S sum, const T t, const Args... args)
template<typename SummationType , typename... Args>
std::optional< SummationType >	NaturalSum (const Args... args)
template<typename S , typename... Args>
S	SetToNaturalSumOrMax (S &var, const Args... args)
template<typename Result , typename Source >
Result	NaturalCast (const Source s)

Typedef Documentation

AllUnsigned

template<typename T , typename U >

using AllUnsigned = typename std::conditional< std::is_unsigned<T>::value && std::is_unsigned<U>::value, std::true_type, std::false_type >::type

detects a pair of unsigned types reduces code duplication in declarations further below

Definition at line 38 of file SquidMath.h.

Function Documentation

AssertNaturalType()

template<typename T >

constexpr void AssertNaturalType ( )

constexpr

Definition at line 62 of file SquidMath.h.

IncreaseSum() [1/2]

template<typename S , typename T >

std::optional< S > IncreaseSum	(	const S	s,
		const T	t
	)

Definition at line 144 of file SquidMath.h.

Referenced by Store::ParsingBuffer::appended(), Store::ParsingBuffer::growSpace(), and IncreaseSum().

IncreaseSum() [2/2]

template<typename S , typename T , typename... Args>

std::optional< S > IncreaseSum	(	const S	sum,
		const T	t,
		const Args...	args
	)

Returns

a non-overflowing sum of the arguments (or nothing)

Definition at line 155 of file SquidMath.h.

References head, and IncreaseSum().

IncreaseSumInternal() [1/2]

template<typename S , typename A , typename B , std::enable_if_t< AllUnsigned< A, B >::value, int > = 0>

std::optional< S > IncreaseSumInternal	(	const A	a,
		const B	b
	)

This IncreaseSumInternal() overload is optimized for speed.

Returns

a non-overflowing sum of the two unsigned arguments (or nothing) \prec both argument types are unsigned

Definition at line 76 of file SquidMath.h.

IncreaseSumInternal() [2/2]

template<typename S , typename A , typename B , std::enable_if_t<!AllUnsigned< A, B >::value, int > = 0>

std::optional< S > constexpr IncreaseSumInternal ( const A  a, const B  b  )

constexpr

This IncreaseSumInternal() overload supports a larger variety of types.

Returns

a non-overflowing sum of the two arguments (or nothing)

nothing if at least one of the arguments is negative \prec at least one of the argument types is signed

Definition at line 112 of file SquidMath.h.

References Less().

Less()

template<typename A , typename B >

constexpr bool Less ( const A  a, const B  b  )

constexpr

Definition at line 48 of file SquidMath.h.

Referenced by Store::SwapMetaUnpacker::SwapMetaUnpacker(), ccNameByType(), IncreaseSumInternal(), AnyP::Uri::parsePort(), HttpReply::parseTerminatedPrefix(), peer_Inst(), clientReplyContext::processReplyAccessResult(), store_client::readBody(), store_client::skipHttpHeadersFromDisk(), and Store::UnpackPrefix().

NaturalCast()

template<typename Result , typename Source >

Result NaturalCast

(

const Source

s

)

converts a given non-negative integer into an integer of a given type without loss of information or undefined behavior

Definition at line 186 of file SquidMath.h.

NaturalSum()

template<typename SummationType , typename... Args>

std::optional< SummationType > NaturalSum

(

const Args...

args

)

Returns

an exact, non-overflowing sum of the arguments (or nothing)

Definition at line 167 of file SquidMath.h.

SetToNaturalSumOrMax()

template<typename S , typename... Args>

S SetToNaturalSumOrMax	(	S &	var,
		const Args...	args
	)

Safely resets the given variable to NaturalSum() of the given arguments. If the sum overflows, resets to variable's maximum possible value.

Returns

the new variable value (like an assignment operator would)

Definition at line 176 of file SquidMath.h.

Referenced by ClpMap< Key, Value, MemoryUsedBy >::Entry::Entry(), and TestMath::testNaturalSum().