MR::FastInt< nBits > Class Template Reference

#include <MRMesh/MRFastInt.h>

Public Member Functions
	FastInt () noexcept=default
template<typename T> requires detail::cFitsFastInt128<T>
constexpr	FastInt (T v) noexcept
	sign-extends the given value, which must fit in 128 bits
template<int mBits> requires ( mBits < nBits )
constexpr	FastInt (const FastInt< mBits > &v) noexcept
	sign-extends a narrower value of this family
template<int mBits> requires ( mBits > nBits )
constexpr	FastInt (const FastInt< mBits > &v) noexcept
constexpr int	sign () const noexcept
	-1, 0 or 1 if the value is negative, zero or positive respectively
constexpr FastInt &	operator+= (const FastInt &b) noexcept
constexpr FastInt &	operator-= (const FastInt &b) noexcept
constexpr FastInt	operator- () const noexcept

Public Attributes
std::array< std::uint64_t, numWords >	w = {}
	two's complement representation: w[0] + 2^64 * w[1] + ... + 2^(nBits-64) * std::int64_t( w[numWords-1] )

Static Public Attributes
static constexpr int	numWords = nBits / 64
	the number of words in the representation below

Friends
constexpr FastInt	operator+ (FastInt a, const FastInt &b) noexcept
constexpr FastInt	operator- (FastInt a, const FastInt &b) noexcept
constexpr bool	operator== (const FastInt &a, const FastInt &b) noexcept
constexpr std::strong_ordering	operator<=> (const FastInt &a, const FastInt &b) noexcept

Detailed Description

template<int nBits>
class MR::FastInt< nBits >

signed integer of nBits bits, which must be a multiple of 64 and at least 192 (below that use FastInt128 with Int64Mul128 and Int128Mul256); the product of two of them is exact, because it is twice as wide as the arguments; as FastInt128 it lacks a sqrt-function and stream input/output

Constructor & Destructor Documentation

FastInt() [1/4]

template<int nBits>

MR::FastInt< nBits >::FastInt ( )

defaultnoexcept

FastInt() [2/4]

template<int nBits>

template<typename T>
requires detail::cFitsFastInt128<T>

MR::FastInt< nBits >::FastInt ( T v )

inlineconstexprnoexcept

sign-extends the given value, which must fit in 128 bits

FastInt() [3/4]

template<int nBits>

template<int mBits>
requires ( mBits < nBits )

MR::FastInt< nBits >::FastInt ( const FastInt< mBits > & v )

inlineconstexprnoexcept

sign-extends a narrower value of this family

FastInt() [4/4]

template<int nBits>

template<int mBits>
requires ( mBits > nBits )

MR::FastInt< nBits >::FastInt ( const FastInt< mBits > & v )

inlineexplicitconstexprnoexcept

takes the lowest nBits bits of a wider value of this family, which must be enough to represent it exactly; as every product below widens, this is how a value with a proven bound returns to the narrow type where it belongs

the value does not fit in nBits bits

Member Function Documentation

operator+=()

template<int nBits>

FastInt & MR::FastInt< nBits >::operator+= ( const FastInt< nBits > & b )

inlineconstexprnoexcept

operator-()

template<int nBits>

FastInt MR::FastInt< nBits >::operator- ( ) const

inlinenodiscardconstexprnoexcept

operator-=()

template<int nBits>

FastInt & MR::FastInt< nBits >::operator-= ( const FastInt< nBits > & b )

inlineconstexprnoexcept

sign()

template<int nBits>

int MR::FastInt< nBits >::sign ( ) const

inlinenodiscardconstexprnoexcept

-1, 0 or 1 if the value is negative, zero or positive respectively

Friends And Related Symbol Documentation

operator+

template<int nBits>

FastInt operator+ ( FastInt< nBits > a, const FastInt< nBits > & b )

friend

operator-

template<int nBits>

FastInt operator- ( FastInt< nBits > a, const FastInt< nBits > & b )

friend

operator<=>

template<int nBits>

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

friend

operator==

template<int nBits>

bool operator== ( const FastInt< nBits > & a, const FastInt< nBits > & b )

friend

Member Data Documentation

numWords

template<int nBits>

int MR::FastInt< nBits >::numWords = nBits / 64

staticconstexpr

the number of words in the representation below

w

template<int nBits>

std::array<std::uint64_t, numWords> MR::FastInt< nBits >::w = {}

two's complement representation: w[0] + 2^64 * w[1] + ... + 2^(nBits-64) * std::int64_t( w[numWords-1] )

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

• MRMesh/MRFastInt.h