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macro_rules! decode_float {
($name: ident, $f: ty, $u: ty) => {
pub fn $name(f: $f) -> ($u, i16) {
const BITS: u32 = core::mem::size_of::<$f>() as u32 * 8;
const MANT_MASK: $u = <$u>::MAX >> (BITS - (<$f>::MANTISSA_DIGITS - 1));
const EXP_MASK: $u = <$u>::MAX >> 1;
const BIAS: i16 = <$f>::MAX_EXP as i16 - 1;
let bits = f.to_bits();
let exp = ((bits & EXP_MASK) >> (<$f>::MANTISSA_DIGITS - 1)) as i16;
let mut mant = bits & MANT_MASK;
if exp != 0 {
mant |= (1 << (<$f>::MANTISSA_DIGITS - 1));
}
(mant, exp - (BIAS + <$f>::MANTISSA_DIGITS as i16 - 1))
}
};
}
decode_float!(decode_f32, f32, u32);
decode_float!(decode_f64, f64, u64);
macro_rules! buint_as_int {
($BUint: ident, $Digit: ident; $($int: ty), *) => {
$(impl_const! {
impl<const N: usize> const CastFrom<$BUint<N>> for $int {
#[must_use = doc::must_use_op!()]
#[inline]
fn cast_from(from: $BUint<N>) -> Self {
let mut out = 0;
let mut i = 0;
while i << crate::digit::$Digit::BIT_SHIFT < <$int>::BITS as usize && i < N {
out |= from.digits[i] as $int << (i << crate::digit::$Digit::BIT_SHIFT);
i += 1;
}
out
}
}
})*
};
}
macro_rules! buint_as_float {
($BUint: ident, $f: ty) => {
impl<const N: usize> CastFrom<$BUint<N>> for $f {
#[must_use = doc::must_use_op!()]
#[inline]
fn cast_from(from: $BUint<N>) -> Self {
crate::buint::as_float::cast_float_from_uint(from)
/*if from.is_zero() {
return 0.0;
}
let bits = from.bits();
let mut mant = if $BUint::<N>::BITS > <$u>::BITS {
if bits < <$f>::MANTISSA_DIGITS {
<$u>::cast_from(from) << (<$f>::MANTISSA_DIGITS - bits)
} else {
<$u>::cast_from(from >> (bits - <$f>::MANTISSA_DIGITS))
}
} else if bits < <$f>::MANTISSA_DIGITS {
<$u>::cast_from(from) << (<$f>::MANTISSA_DIGITS - bits)
} else {
<$u>::cast_from(from) >> (bits - <$f>::MANTISSA_DIGITS)
};
let mut round_up = true;
if bits <= <$f>::MANTISSA_DIGITS
|| !from.bit(bits - (<$f>::MANTISSA_DIGITS + 1))
|| (mant & 1 == 0
&& from.trailing_zeros() == bits - (<$f>::MANTISSA_DIGITS + 1))
{
round_up = false;
}
let mut exp = bits as $u + (<$f>::MAX_EXP - 1) as $u - 1;
if round_up {
mant += 1;
if mant.leading_zeros() == <$u>::BITS - (<$f>::MANTISSA_DIGITS + 1) {
exp += 1;
}
}
if exp > 2 * (<$f>::MAX_EXP as $u) - 1 {
return <$f>::INFINITY;
}
let mant = <$u>::cast_from(mant);
<$f>::from_bits(
(exp << (<$f>::MANTISSA_DIGITS - 1))
| (mant & (<$u>::MAX >> (<$u>::BITS - (<$f>::MANTISSA_DIGITS as u32 - 1)))),
)*/
}
}
};
}
macro_rules! as_buint {
($BUint: ident, $Digit: ident; $($ty: ty), *) => {
$(crate::nightly::const_impl! {
impl<const N: usize> const CastFrom<$ty> for $BUint<N> {
#[must_use = doc::must_use_op!()]
#[inline]
fn cast_from(mut from: $ty) -> Self {
#[allow(unused_comparisons)]
let mut out = if from < 0 {
Self::MAX
} else {
Self::MIN
};
let mut i = 0;
while from != 0 && i < N {
let masked = from as $Digit & $Digit::MAX;
out.digits[i] = masked;
if <$ty>::BITS <= $Digit::BITS {
from = 0;
} else {
from = from.wrapping_shr($Digit::BITS);
}
i += 1;
}
out
}
}
})*
};
}
use crate::cast::CastFrom;
use crate::doc;
use crate::nightly::impl_const;
// use core::mem::MaybeUninit;
macro_rules! cast {
($BUint: ident, $BInt: ident, $Digit: ident) => {
impl<const N: usize> $BUint<N> {
crate::nightly::const_fn! {
#[inline]
const fn cast_up<const M: usize>(self, digit: $Digit) -> $BUint<M> {
let mut digits = [digit; M];
let mut i = M - N;
while i < M {
let index = i - (M - N);
digits[index] = self.digits[index];
i += 1;
}
$BUint::from_digits(digits)
}
}
crate::nightly::const_fn! {
#[inline]
const fn cast_down<const M: usize>(self) -> $BUint<M> {
let mut out = $BUint::ZERO;
let mut i = 0;
while i < M {
out.digits[i] = self.digits[i];
i += 1;
}
out
}
}
}
buint_as_int!($BUint, $Digit; u8, u16, u32, u64, u128, usize, i8, i16, i32, i64, i128, isize);
buint_as_float!($BUint, f32);
buint_as_float!($BUint, f64);
as_buint!($BUint, $Digit; u8, u16, u32, u64, u128, usize, i8, i16, i32, i64, i128, isize);
impl_const! {
impl<const N: usize> const CastFrom<bool> for $BUint<N> {
#[must_use = doc::must_use_op!()]
#[inline]
fn cast_from(from: bool) -> Self {
if from {
Self::ONE
} else {
Self::ZERO
}
}
}
}
impl_const! {
impl<const N: usize> const CastFrom<char> for $BUint<N> {
#[must_use = doc::must_use_op!()]
#[inline]
fn cast_from(from: char) -> Self {
Self::cast_from(from as u32)
}
}
}
impl_const! {
impl<const N: usize, const M: usize> const CastFrom<$BUint<M>> for $BUint<N> {
#[must_use = doc::must_use_op!()]
#[inline]
fn cast_from(from: $BUint<M>) -> Self {
if M < N {
from.cast_up(0)
} else {
from.cast_down()
}
}
}
}
impl_const! {
impl<const N: usize, const M: usize> const CastFrom<$BInt<M>> for $BUint<N> {
#[must_use = doc::must_use_op!()]
#[inline]
fn cast_from(from: $BInt<M>) -> Self {
if M < N {
let padding_digit = if from.is_negative() {
$Digit::MAX
} else {
0
};
from.to_bits().cast_up(padding_digit)
} else {
from.to_bits().cast_down()
}
}
}
}
impl<const N: usize> CastFrom<f32> for $BUint<N> {
#[must_use = doc::must_use_op!()]
#[inline]
fn cast_from(from: f32) -> Self {
crate::buint::float_as::uint_cast_from_float(from)
}
}
impl<const N: usize> CastFrom<f64> for $BUint<N> {
#[must_use = doc::must_use_op!()]
#[inline]
fn cast_from(from: f64) -> Self {
crate::buint::float_as::uint_cast_from_float(from)
}
}
};
}
crate::macro_impl!(cast);
macro_rules! buint_as_different_digit_bigint {
($BUint: ident, $BInt: ident, $Digit: ident; $(($OtherBUint: ident, $OtherDigit: ident)), *) => {
$(
crate::nightly::const_impl! {
impl<const N: usize, const M: usize> const crate::cast::CastFrom<$OtherBUint<M>> for $BUint<N> {
#[must_use = doc::must_use_op!()]
#[inline]
fn cast_from(from: $OtherBUint<M>) -> Self {
let mut out = Self::ZERO;
if $Digit::BITS < $OtherDigit::BITS {
const DIVIDE_COUNT: usize = ($OtherDigit::BITS / $Digit::BITS) as usize;
let stop_index: usize = if <$OtherBUint<M>>::BITS > <$BUint<N>>::BITS {
N
} else {
M * DIVIDE_COUNT
};
let mut i = 0;
while i < stop_index {
let wider_digit = from.digits[i / DIVIDE_COUNT];
let mini_shift = i % DIVIDE_COUNT;
let digit = (wider_digit >> (mini_shift << digit::$Digit::BIT_SHIFT)) as $Digit;
out.digits[i] = digit;
i += 1;
}
} else {
const DIVIDE_COUNT: usize = ($Digit::BITS / $OtherDigit::BITS) as usize;
let stop_index: usize = if <$OtherBUint<M>>::BITS > <$BUint<N>>::BITS {
N * DIVIDE_COUNT
} else {
M
};
let mut current_digit: $Digit = 0;
let mut i = 0;
while i < stop_index {
let mini_shift = i % DIVIDE_COUNT;
current_digit |= (from.digits[i] as $Digit) << (mini_shift << digit::$OtherDigit::BIT_SHIFT);
if mini_shift == DIVIDE_COUNT - 1 || i == stop_index - 1 {
out.digits[i / DIVIDE_COUNT] = current_digit;
current_digit = 0;
}
i += 1;
}
}
out
}
}
}
crate::nightly::const_impl! {
impl<const N: usize, const M: usize> const crate::cast::CastFrom<$OtherBUint<M>> for $BInt<N> {
#[must_use = doc::must_use_op!()]
#[inline]
fn cast_from(from: $OtherBUint<M>) -> Self {
Self::from_bits($BUint::cast_from(from))
}
}
}
)*
}
}
pub(crate) use buint_as_different_digit_bigint;