enum class byte : unsigned char {};
(since C++17)std::byte is a distinct type that implements the concept of byte as specified in the C++ language definition.
Like unsigned char, it can be used to access raw memory occupied by other objects (object representation), but unlike unsigned char, it is not a character type and is not an arithmetic type. std::byte models a mere collection of bits, supporting only bitshift operations with an integer, and bitwise and comparison operations with another std::byte.
template< class IntegerType >
constexpr IntegerType to_integer( std::byte b ) noexcept;
Equivalent to: return IntegerType(b); This overload participates in overload resolution only if std::is_integral_v<IntegerType> is true.
std::operator<<=,operator>>=template< class IntegerType >
constexpr std::byte& operator<<=( std::byte& b, IntegerType shift ) noexcept;
template< class IntegerType >
constexpr std::byte& operator>>=( std::byte& b, IntegerType shift ) noexcept;
Equivalent to:
return b = b << shift;This overload participates in overload resolution only if
std::is_integral_v<IntegerType>is
true.
2)Equivalent to:
return b = b >> shift;This overload participates in overload resolution only if std::is_integral_v<IntegerType> is true.
std::operator<<,operator>>template< class IntegerType >
constexpr std::byte operator<<( std::byte b, IntegerType shift ) noexcept;
template< class IntegerType >
constexpr std::byte operator>>( std::byte b, IntegerType shift ) noexcept;
Equivalent to:
return std::byte(static_cast<unsigned int>(b) << shift);This overload participates in overload resolution only if
std::is_integral_v<IntegerType>is
true.
2)Equivalent to:
return std::byte(static_cast<unsigned int>(b) >> shift);This overload participates in overload resolution only if std::is_integral_v<IntegerType> is true.
std::operator|=,operator&=,operator^=constexpr std::byte& operator|=( std::byte& l, std::byte r ) noexcept;
(1) (since C++17)constexpr std::byte& operator&=( std::byte& l, std::byte r ) noexcept;
(2) (since C++17)constexpr std::byte& operator^=( std::byte& l, std::byte r ) noexcept;
(3) (since C++17)1) Equivalent to: return l = l | r;.
2) Equivalent to: return l = l & r;.
3) Equivalent to: return l = l ^ r;.
std::operator|,operator&,operator^,operator~constexpr std::byte operator|( std::byte l, std::byte r ) noexcept;
(1) (since C++17)constexpr std::byte operator&( std::byte l, std::byte r ) noexcept;
(2) (since C++17)constexpr std::byte operator^( std::byte l, std::byte r ) noexcept;
(3) (since C++17)constexpr std::byte operator~( std::byte b ) noexcept;
(4) (since C++17)1) Equivalent to: return std::byte(static_cast<unsigned int>(l) | static_cast<unsigned int>(r));.
2) Equivalent to: return std::byte(static_cast<unsigned int>(l) & static_cast<unsigned int>(r));.
3) Equivalent to: return std::byte(static_cast<unsigned int>(l) ^ static_cast<unsigned int>(r));.
4) Equivalent to: return std::byte(~static_cast<unsigned int>(b));
[edit] NotesA numeric value n can be converted to a byte value using std::byte{n}, due to C++17 relaxed enum class initialization rules.
A byte can be converted to a numeric value (such as to produce an integer hash of an object) the usual way with an explicit conversion or alternatively with std::to_integer.
#include <bitset>
#include <cassert>
#include <cstddef>
#include <iostream>
#include <utility>
std::ostream& operator<<(std::ostream& os, std::byte b)
{
return os << std::bitset<8>(std::to_integer<int>(b));
}
int main()
{
// std::byte y = 1; // Error: cannot convert int to byte.
std::byte y{1}; // OK
// if (y == 13) {} // Error: cannot be compared.
if (y == std::byte{13}) {} // OK, bytes are comparable
int arr[]{1, 2, 3};
// int c = a[y]; // Error: array subscript is not an integer
[[maybe_unused]] int i = arr[std::to_integer<int>(y)]; // OK
[[maybe_unused]] int j = arr[std::to_underlying(y)]; // OK
auto to_int = [](std::byte b) { return std::to_integer<int>(b); };
std::byte b{42};
assert(to_int(b) == 0b00101010);
std::cout << b << '\n';
// b *= 2; // Error: b is not of arithmetic type
b <<= 1;
assert(to_int(b) == 0b01010100);
b >>= 1;
assert(to_int(b) == 0b00101010);
assert(to_int(b << 1) == 0b01010100);
assert(to_int(b >> 1) == 0b00010101);
b |= std::byte{0b11110000};
assert(to_int(b) == 0b11111010);
b &= std::byte{0b11110000};
assert(to_int(b) == 0b11110000);
b ^= std::byte{0b11111111};
assert(to_int(b) == 0b00001111);
}
Output:
RetroSearch is an open source project built by @garambo | Open a GitHub Issue
Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo
HTML:
3.2
| Encoding:
UTF-8
| Version:
0.7.4