conversion.hpp File Reference

Numeric conversion. More...

#include <type_traits>
#include <limits>
#include <cstdint>
#include <cstddef>

Go to the source code of this file.

Namespaces
namespace	m5
	Top level namespace of M5.

Functions
template<size_t Bits, typename T >
constexpr auto	m5::utility::unsigned_to_signed (const T v) -> typename std::make_signed< T >::type
	Convert an unsigned integer of any maximum number of bits to a signed integer.
template<typename T >
constexpr auto	m5::utility::unsigned_to_signed (const T v, const size_t bits) -> typename std::make_signed< T >::type
	Convert an unsigned integer to a signed integer, with the number of bits given at run time.
template<typename To , typename From >
constexpr To	m5::utility::saturate_cast (const From v)
	Narrows an unsigned integer, saturating at the maximum of the destination.

Detailed Description

Numeric conversion.

Function Documentation

saturate_cast()

template<typename To , typename From >

To m5::utility::saturate_cast ( const From v )

constexpr

Narrows an unsigned integer, saturating at the maximum of the destination.

Template Parameters

To	Destination unsigned integer type
From	Source unsigned integer type

Parameters

v	Value to convert

Returns

v, or the maximum of To when v exceeds it

// 0x1FFFF does not fit in uint16_t
uint16_t u16 = saturate_cast<uint16_t>(size_t{0x1FFFF});
// u16 is 0xFFFF (Not 0xFFFF & 0x1FFFF == 0xFFFF... it saturates, it does not wrap)

Note

Only unsigned to unsigned for now. The comparison goes through uintmax_t, so a From narrower than To is handled as well

unsigned_to_signed() [1/2]

template<size_t Bits, typename T >

auto m5::utility::unsigned_to_signed ( const T v ) -> typename std::make_signed<T>::type

constexpr

Convert an unsigned integer of any maximum number of bits to a signed integer.

Template Parameters

Bits	Number of bits assumed by value uint32_t u24{0x00FFFFFF}; // 24 bit unsigned int to int32_t uint32_t s32 = unsigned_to_signed<24>(u24); // s32 is -1 (Not 16777215)

unsigned_to_signed() [2/2]

template<typename T >

auto m5::utility::unsigned_to_signed ( const T v, const size_t bits ) -> typename std::make_signed<T>::type

constexpr

Convert an unsigned integer to a signed integer, with the number of bits given at run time.

Template Parameters

T	Unsigned integer type of the value

Parameters

v	Value to convert
bits	Number of bits assumed by value (1 to the width of T; 0 yields 0) // A table-driven field whose width is only known at run time int32_t s = unsigned_to_signed(raw, signal.bit_length);

Note

Use the unsigned_to_signed<Bits>() overload whenever the width is a constant: it can check the width against T at compile time, which this one cannot