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|
use crate::traits::{Float, Sealed};
use core::{
alloc::{Layout, LayoutErr},
cmp,
mem::{self, transmute},
};
#[cfg(feature = "std")]
use std::ffi::OsString;
#[cfg(feature = "std")]
use std::path::PathBuf;
#[cfg(feature = "std")]
pub trait PathBuf_v1_44: Sealed<PathBuf> {
fn with_capacity(capacity: usize) -> PathBuf;
fn capacity(&self) -> usize;
fn clear(&mut self);
fn reserve(&mut self, additional: usize);
fn reserve_exact(&mut self, additional: usize);
fn shrink_to_fit(&mut self);
}
#[cfg(feature = "std")]
impl PathBuf_v1_44 for PathBuf {
fn with_capacity(capacity: usize) -> PathBuf {
OsString::with_capacity(capacity).into()
}
fn capacity(&self) -> usize {
unsafe { transmute::<_, &OsString>(self) }.capacity()
}
fn clear(&mut self) {
unsafe { transmute::<_, &mut OsString>(self) }.clear()
}
fn reserve(&mut self, additional: usize) {
unsafe { transmute::<_, &mut OsString>(self) }.reserve(additional)
}
fn reserve_exact(&mut self, additional: usize) {
unsafe { transmute::<_, &mut OsString>(self) }.reserve_exact(additional)
}
fn shrink_to_fit(&mut self) {
unsafe { transmute::<_, &mut OsString>(self) }.shrink_to_fit()
}
}
pub trait Layout_v1_44: Sealed<Layout> {
fn align_to(&self, align: usize) -> Result<Layout, LayoutErr>;
fn pad_to_align(&self) -> Layout;
fn array<T>(n: usize) -> Result<Layout, LayoutErr>;
fn extend(&self, next: Layout) -> Result<(Layout, usize), LayoutErr>;
}
impl Layout_v1_44 for Layout {
#[inline]
fn align_to(&self, align: usize) -> Result<Self, LayoutErr> {
Layout::from_size_align(self.size(), cmp::max(self.align(), align))
}
#[inline]
fn pad_to_align(&self) -> Layout {
let pad = padding_needed_for(self, self.align());
let new_size = self.size() + pad;
Layout::from_size_align(new_size, self.align()).unwrap()
}
#[inline]
fn array<T>(n: usize) -> Result<Self, LayoutErr> {
repeat(&Layout::new::<T>(), n).map(|(k, offs)| {
debug_assert!(offs == mem::size_of::<T>());
k
})
}
#[inline]
fn extend(&self, next: Self) -> Result<(Self, usize), LayoutErr> {
let new_align = cmp::max(self.align(), next.align());
let pad = padding_needed_for(self, next.align());
let offset = self.size().checked_add(pad).ok_or(layout_err())?;
let new_size = offset.checked_add(next.size()).ok_or(layout_err())?;
let layout = Layout::from_size_align(new_size, new_align)?;
Ok((layout, offset))
}
}
fn padding_needed_for(zelf: &Layout, align: usize) -> usize {
let len = zelf.size();
let len_rounded_up = len.wrapping_add(align).wrapping_sub(1) & !align.wrapping_sub(1);
len_rounded_up.wrapping_sub(len)
}
#[inline]
fn repeat(zelf: &Layout, n: usize) -> Result<(Layout, usize), LayoutErr> {
let padded_size = zelf.size() + padding_needed_for(zelf, zelf.align());
let alloc_size = padded_size.checked_mul(n).ok_or(layout_err())?;
unsafe {
Ok((
Layout::from_size_align_unchecked(alloc_size, zelf.align()),
padded_size,
))
}
}
#[inline(always)]
fn layout_err() -> LayoutErr {
// We can safely transmute this, as zero-sized types have no actual memory
// representation. If `LayoutErr` ever has the addition of a field, this
// will stop compiling (rather than creating undefined behavior).
unsafe { transmute(()) }
}
mod sealed {
pub trait FloatToInt<Int> {
unsafe fn to_int_unchecked(self) -> Int;
}
macro_rules! impl_float_to_int {
($float:ident => $($int:ident)+) => {$(
impl FloatToInt<$int> for $float {
#[inline]
unsafe fn to_int_unchecked(self) -> $int {
self as $int
}
}
)+}
}
impl_float_to_int!(f32 => u8 u16 u32 u64 u128 usize i8 i16 i32 i64 i128 isize);
impl_float_to_int!(f64 => u8 u16 u32 u64 u128 usize i8 i16 i32 i64 i128 isize);
}
pub trait float_v1_44: Float {
unsafe fn to_int_unchecked<Int>(self) -> Int
where
Self: sealed::FloatToInt<Int>;
}
impl float_v1_44 for f32 {
unsafe fn to_int_unchecked<Int>(self) -> Int
where
f32: sealed::FloatToInt<Int>,
{
sealed::FloatToInt::to_int_unchecked(self)
}
}
impl float_v1_44 for f64 {
unsafe fn to_int_unchecked<Int>(self) -> Int
where
f64: sealed::FloatToInt<Int>,
{
sealed::FloatToInt::to_int_unchecked(self)
}
}
|
