22 General utilities library [utilities]

22.15 Bit manipulation [bit]

22.15.5 Integral powers of 2 [bit.pow.two]

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template<class T> constexpr bool has_single_bit(T x) noexcept;
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Constraints: T is an unsigned integer type ([basic.fundamental]).
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Returns: true if x is an integral power of two; false otherwise.
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template<class T> constexpr T bit_ceil(T x);
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Let N be the smallest power of 2 greater than or equal to x.
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Constraints: T is an unsigned integer type ([basic.fundamental]).
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Preconditions: N is representable as a value of type T.
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Returns: N.
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Throws: Nothing.
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Remarks: A function call expression that violates the precondition in the Preconditions: element is not a core constant expression ([expr.const]).
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template<class T> constexpr T bit_floor(T x) noexcept;
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Constraints: T is an unsigned integer type ([basic.fundamental]).
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Returns: If x == 0, 0; otherwise the maximal value y such that has_single_bit(y) is true and y <= x.
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template<class T> constexpr int bit_width(T x) noexcept;
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Constraints: T is an unsigned integer type ([basic.fundamental]).
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Returns: If x == 0, 0; otherwise one plus the base-2 logarithm of x, with any fractional part discarded.