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use integer::Integer;
use malachite_base::num::arithmetic::traits::{
ShlRound, ShlRoundAssign, ShrRound, ShrRoundAssign, UnsignedAbs,
};
use malachite_base::num::basic::traits::Zero;
use malachite_base::rounding_modes::RoundingMode;
use std::ops::{Shl, ShlAssign};
fn shl_round_signed_ref<'a, U, S: Copy + Ord + UnsignedAbs<Output = U> + Zero>(
x: &'a Integer,
bits: S,
rm: RoundingMode,
) -> Integer
where
&'a Integer: Shl<U, Output = Integer> + ShrRound<U, Output = Integer>,
{
if bits >= S::ZERO {
x << bits.unsigned_abs()
} else {
x.shr_round(bits.unsigned_abs(), rm)
}
}
fn shl_round_assign_i<U, S: Copy + Ord + UnsignedAbs<Output = U> + Zero>(
x: &mut Integer,
bits: S,
rm: RoundingMode,
) where
Integer: ShlAssign<U> + ShrRoundAssign<U>,
{
if bits >= S::ZERO {
*x <<= bits.unsigned_abs();
} else {
x.shr_round_assign(bits.unsigned_abs(), rm);
}
}
macro_rules! impl_shl_round_signed {
($t:ident) => {
impl ShlRound<$t> for Integer {
type Output = Integer;
/// Left-shifts an [`Integer`] (multiplies or divides it by a power of 2), taking it by
/// value, and rounds according to the specified rounding mode.
///
/// Passing `RoundingMode::Floor` is equivalent to using `>>`. To test whether
/// `RoundingMode::Exact` can be passed, use
/// `bits > 0 || self.divisible_by_power_of_2(bits)`. Rounding might only be necessary
/// if `bits` is negative.
///
/// Let $q = x2^k$:
///
/// $f(x, k, \mathrm{Down}) = f(x, y, \mathrm{Floor}) = \lfloor q \rfloor.$
///
/// $f(x, k, \mathrm{Up}) = f(x, y, \mathrm{Ceiling}) = \lceil q \rceil.$
///
/// $$
/// f(x, k, \mathrm{Nearest}) = \begin{cases}
/// \lfloor q \rfloor & \text{if}
/// \\quad q - \lfloor q \rfloor < \frac{1}{2}, \\\\
/// \lceil q \rceil & \text{if}
/// \\quad q - \lfloor q \rfloor > \frac{1}{2}, \\\\
/// \lfloor q \rfloor & \text{if} \\quad q - \lfloor q \rfloor =
/// \frac{1}{2} \\ \text{and} \\ \lfloor q \rfloor
/// \\ \text{is even}, \\\\
/// \lceil q \rceil &
/// \text{if} \\quad q - \lfloor q \rfloor = \frac{1}{2} \\ \text{and}
/// \\ \lfloor q \rfloor \\ \text{is odd}.
/// \end{cases}
/// $$
///
/// $f(x, k, \mathrm{Exact}) = q$, but panics if $q \notin \N$.
///
/// # Worst-case complexity
/// $T(n, m) = O(n + m)$
///
/// $M(n, m) = O(n + m)$
///
/// where $T$ is time, $M$ is additional memory, $n$ is `self.significant_bits()`, and
/// $m$ is `max(bits, 0)`.
///
/// # Panics
/// Let $k$ be `bits`. Panics if $k$ is negative and `rm` is `RoundingMode::Exact` but
/// `self` is not divisible by $2^{-k}$.
///
/// # Examples
/// See [here](super::shl_round#shl_round).
#[inline]
fn shl_round(mut self, bits: $t, rm: RoundingMode) -> Integer {
self.shl_round_assign(bits, rm);
self
}
}
impl<'a> ShlRound<$t> for &'a Integer {
type Output = Integer;
/// Left-shifts an [`Integer`] (multiplies or divides it by a power of 2), taking it by
/// reference, and rounds according to the specified rounding mode.
///
/// Passing `RoundingMode::Floor` is equivalent to using `>>`. To test whether
/// `RoundingMode::Exact` can be passed, use
/// `bits > 0 || self.divisible_by_power_of_2(bits)`. Rounding might only be necessary
/// if `bits` is negative.
///
/// Let $q = x2^k$:
///
/// $f(x, k, \mathrm{Down}) = f(x, y, \mathrm{Floor}) = \lfloor q \rfloor.$
///
/// $f(x, k, \mathrm{Up}) = f(x, y, \mathrm{Ceiling}) = \lceil q \rceil.$
///
/// $$
/// f(x, k, \mathrm{Nearest}) = \begin{cases}
/// \lfloor q \rfloor & \text{if}
/// \\quad q - \lfloor q \rfloor < \frac{1}{2}, \\\\
/// \lceil q \rceil & \text{if}
/// \\quad q - \lfloor q \rfloor > \frac{1}{2}, \\\\
/// \lfloor q \rfloor & \text{if} \\quad q - \lfloor q \rfloor =
/// \frac{1}{2} \\ \text{and} \\ \lfloor q \rfloor
/// \\ \text{is even}, \\\\
/// \lceil q \rceil &
/// \text{if} \\quad q - \lfloor q \rfloor = \frac{1}{2} \\ \text{and}
/// \\ \lfloor q \rfloor \\ \text{is odd}.
/// \end{cases}
/// $$
///
/// $f(x, k, \mathrm{Exact}) = q$, but panics if $q \notin \N$.
///
/// # Worst-case complexity
/// $T(n, m) = O(n + m)$
///
/// $M(n, m) = O(n + m)$
///
/// where $T$ is time, $M$ is additional memory, $n$ is `self.significant_bits()`, and
/// $m$ is `max(bits, 0)`.
///
/// # Panics
/// Let $k$ be `bits`. Panics if $k$ is negative and `rm` is `RoundingMode::Exact` but
/// `self` is not divisible by $2^{-k}$.
///
/// # Examples
/// See [here](super::shl_round#shl_round).
#[inline]
fn shl_round(self, bits: $t, rm: RoundingMode) -> Integer {
shl_round_signed_ref(self, bits, rm)
}
}
impl ShlRoundAssign<$t> for Integer {
/// Left-shifts an [`Integer`] (multiplies or divides it by a power of 2) and rounds
/// according to the specified rounding mode, in place.
///
/// Passing `RoundingMode::Floor` is equivalent to using `>>`. To test whether
/// `RoundingMode::Exact` can be passed, use
/// `bits > 0 || self.divisible_by_power_of_2(bits)`. Rounding might only be
/// necessary if `bits` is negative.
///
/// See the [`ShlRound`](malachite_base::num::arithmetic::traits::ShlRound)
/// documentation for details.
///
/// # Worst-case complexity
/// $T(n, m) = O(n + m)$
///
/// $M(n, m) = O(n + m)$
///
/// where $T$ is time, $M$ is additional memory, $n$ is `self.significant_bits()`, and
/// $m$ is `max(bits, 0)`.
///
/// # Examples
/// See [here](super::shl_round#shl_round_assign).
#[inline]
fn shl_round_assign(&mut self, bits: $t, rm: RoundingMode) {
shl_round_assign_i(self, bits, rm);
}
}
};
}
apply_to_signeds!(impl_shl_round_signed);