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//! Rounding-scheme identifiers. #![allow(dead_code)] /// Rounding type for float-parsing. /// /// Defines the IEEE754 rounding scheme to be used during float parsing. /// In general, this should be set to `NearestTieEven`, the default /// recommended rounding scheme by IEEE754 for binary and decimal /// operations. /// /// # FFI /// /// For interfacing with FFI-code, this may be approximated by: /// ```text /// const int32_t NEAREST_TIE_EVEN = 0; /// const int32_t NEAREST_TIE_AWAY_ZERO = 1; /// const int32_t TOWARD_POSITIVE_INFINITY = 2; /// const int32_t TOWARD_NEGATIVE_INFINITY = 3; /// const int32_t TOWARD_ZERO = 4; /// ``` /// /// # Safety /// /// Assigning any value outside the range `[1-4]` to value of type /// RoundingKind may invoke undefined-behavior. #[repr(i32)] #[derive(Debug, Copy, Clone, Eq, PartialEq)] pub enum RoundingKind { /// Round to the nearest, tie to even. NearestTieEven = 0, /// Round to the nearest, tie away from zero. NearestTieAwayZero = 1, /// Round toward positive infinity. TowardPositiveInfinity = 2, /// Round toward negative infinity. TowardNegativeInfinity = 3, /// Round toward zero. TowardZero = 4, // Hide the internal implementation details, for how we implement // TowardPositiveInfinity, TowardNegativeInfinity, and TowardZero. /// Round to increase the magnitude of the float. /// For example, for a negative number, this rounds to negative infinity, /// for a positive number, to positive infinity. #[doc(hidden)] Upward = -1, /// Round to decrease the magnitude of the float. /// This always rounds toward zero. #[doc(hidden)] Downward = -2, } /// Determine if we are rounding to the nearest value, then tying away. #[inline] pub(crate) fn is_nearest(kind: RoundingKind) -> bool { kind == RoundingKind::NearestTieEven || kind == RoundingKind::NearestTieAwayZero } /// Determine if we are rounding to the nearest value, then tying away. #[inline] pub(crate) fn is_toward(kind: RoundingKind) -> bool { !is_nearest(kind) }