1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101
use integer::Integer;
use malachite_base::num::conversion::traits::{CheckedFrom, ConvertibleFrom, RoundingFrom};
use malachite_base::rounding_modes::RoundingMode;
use natural::Natural;
macro_rules! float_impls {
($f: ident) => {
impl RoundingFrom<$f> for Integer {
/// Converts a primitive float to an [`Integer`], using the specified rounding mode.
///
/// The floating-point value cannot be NaN or infinite.
///
/// # Worst-case complexity
/// $T(n) = O(n)$
///
/// $M(n) = O(n)$
///
/// where $T$ is time, $M$ is additional memory, and $n$ is `value.sci_exponent()`.
///
/// # Panics
/// Panics if `value` is NaN or infinite or if the rounding mode is `Exact` and `value`
/// is not an integer.
///
/// # Examples
/// See [here](super::from_primitive_float#rounding_from).
fn rounding_from(value: $f, rm: RoundingMode) -> Self {
if value >= 0.0 {
Integer {
sign: true,
abs: Natural::rounding_from(value, rm),
}
} else {
-Natural::rounding_from(-value, -rm)
}
}
}
impl From<$f> for Integer {
/// Converts a primitive float to the nearest [`Integer`].
///
/// Floating-point values exactly between two [`Integer`]s are rounded to the even one.
/// The floating point value cannot be NaN or infinite.
///
/// # Worst-case complexity
/// $T(n) = O(n)$
///
/// $M(n) = O(n)$
///
/// where $T$ is time, $M$ is additional memory, and $n$ is `value.sci_exponent()`.
///
/// # Panics
/// Panics if `value` is NaN or infinite.
///
/// # Examples
/// See [here](super::from_primitive_float#from).
fn from(value: $f) -> Integer {
let abs = Natural::from(value.abs());
Integer {
sign: value >= 0.0 || abs == 0,
abs,
}
}
}
impl CheckedFrom<$f> for Integer {
/// Converts a primitive float to an [`Integer`].
///
/// If the input isn't exactly equal to some [`Integer`], `None` is returned.
///
/// # Worst-case complexity
/// $T(n) = O(n)$
///
/// $M(n) = O(n)$
///
/// where $T$ is time, $M$ is additional memory, and $n$ is `value.sci_exponent()`.
///
/// # Examples
/// See [here](super::from_primitive_float#checked_from).
fn checked_from(value: $f) -> Option<Integer> {
Natural::checked_from(value.abs()).map(|n| Integer {
sign: value >= 0.0,
abs: n,
})
}
}
impl ConvertibleFrom<$f> for Integer {
/// Determines whether a primitive float can be exactly converted to an [`Integer`].
///
/// # Worst-case complexity
/// Constant time and additional memory.
///
/// # Examples
/// See [here](super::from_primitive_float#convertible_from).
fn convertible_from(value: $f) -> bool {
Natural::convertible_from(value.abs())
}
}
};
}
apply_to_primitive_floats!(float_impls);