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use alloc::alloc::{alloc, alloc_zeroed, dealloc, Layout};
use core::{
borrow::{Borrow, BorrowMut},
fmt,
hash::{Hash, Hasher},
mem,
num::NonZeroUsize,
ops::{Deref, DerefMut, Index, IndexMut, RangeFull},
ptr,
ptr::NonNull,
};
use awint_core::{Bits, InlAwi};
use const_fn::const_fn;
use crate::awint_internals::*;
#[inline]
pub(crate) const fn layout(w: NonZeroUsize) -> Layout {
// Safety: this produces the exact number of bytes needed to satisfy the raw
// invariants of `Bits`.
unsafe {
Layout::from_size_align_unchecked(
total_digits(w).get() * mem::size_of::<Digit>(),
mem::align_of::<Digit>(),
)
}
}
/// An arbitrary width integer with manually controlled bitwidth. Most
/// arithmetic is wrapping like Rust's integers. All reallocations are
/// explicit.
///
/// This struct implements `Deref<Target = Bits>`, see the main documentation of
/// [Bits](awint_core::Bits) for more. There are also some functions that
/// `InlAwi` and `Bits` do not implement, namely some higher level string
/// serialization functions that require allocation. Also note that `ExtAwi` and
/// `Awi` cannot take advantage of the `const`ness of `Bits` operations, see
/// [InlAwi](awint_core::InlAwi).
///
/// See the crate level documentation of `awint_macros` for more macros and
/// information.
///
/// ```
/// use awint::awi::*;
///
/// fn example(x0: &mut Bits, x1: &Bits) {
/// // when dealing with `Bits` with different bitwidths, use the
/// // `*_resize_` functions or the concatenations of components
/// // macros with unbounded fillers from `awint_macros`
/// x0.sign_resize_(x1);
/// // multiply in place by 2 for an example
/// x0.digit_cin_mul_(0, 2);
/// }
///
/// // using `bw` function for quick `NonZeroUsize` construction from a literal
/// let mut x = ExtAwi::zero(bw(100));
/// assert!(x.is_zero());
/// // constructing an `ExtAwi` from an `InlAwi`
/// let y = ExtAwi::from(inlawi!(-123i16));
/// example(&mut x, &y);
/// assert_eq!(x.as_ref(), inlawi!(-246i100).as_ref());
/// // you can freely mix references originating from both `ExtAwi` and `InlAwi`
/// example(&mut x, &inlawi!(0x10u16));
/// assert_eq!(x, extawi!(0x20u100));
/// ```
#[repr(C)]
pub struct ExtAwi {
_raw_bits: RawBits,
}
/// `ExtAwi` is safe to send between threads since it does not own
/// aliasing memory and has no reference counting mechanism like `Rc`.
unsafe impl Send for ExtAwi {}
/// `ExtAwi` is safe to share between threads since it does not own
/// aliasing memory and has no mutable internal state like `Cell` or `RefCell`.
unsafe impl Sync for ExtAwi {}
impl<'a> ExtAwi {
/// # Safety
///
/// `ptr` should be allocated according to the `extawi::layout` function and
/// all digits initialized. The `Bits` raw invariants should be followed.
#[doc(hidden)]
#[inline]
#[const_fn(cfg(feature = "const_support"))]
pub const fn from_raw_parts(digits: NonNull<Digit>, bw: NonZeroUsize) -> ExtAwi {
ExtAwi {
_raw_bits: RawBits::from_raw_parts(digits, bw),
}
}
/// Returns a reference to `self` in the form of `&Bits`
#[inline]
#[const_fn(cfg(feature = "const_support"))]
#[must_use]
const fn internal_as_ref(&'a self) -> &'a Bits {
// Safety: We copy the `RawBits`, and the explicit lifetimes make sure
// they do not become unbounded.
unsafe {
Bits::from_raw_parts(RawBits::from_raw_parts(
self._raw_bits.as_non_null_ptr(),
self._raw_bits.nzbw(),
))
}
}
/// Returns a reference to `self` in the form of `&mut Bits`
#[inline]
#[const_fn(cfg(feature = "const_support"))]
#[must_use]
const fn internal_as_mut(&'a mut self) -> &'a mut Bits {
// Safety: We copy the `RawBits`, and the explicit lifetimes make sure
// they do not become unbounded.
unsafe {
Bits::from_raw_parts_mut(RawBits::from_raw_parts(
self._raw_bits.as_non_null_ptr(),
self._raw_bits.nzbw(),
))
}
}
/// Returns the bitwidth of this `ExtAwi` as a `NonZeroUsize`
#[inline]
#[const_fn(cfg(feature = "const_support"))]
#[must_use]
pub const fn nzbw(&self) -> NonZeroUsize {
self._raw_bits.nzbw()
}
/// Returns the bitwidth of this `ExtAwi` as a `usize`
#[inline]
#[const_fn(cfg(feature = "const_support"))]
#[must_use]
pub const fn bw(&self) -> usize {
self._raw_bits.bw()
}
/// Returns the total number of digits of this `ExtAwi`
#[doc(hidden)]
#[inline]
#[const_fn(cfg(feature = "const_support"))]
#[must_use]
pub const fn total_digits(&self) -> NonZeroUsize {
self._raw_bits.total_digits()
}
/// Returns a raw pointer to the underlying bit storage. The caller must
/// ensure that the `ExtAwi` outlives the pointer this function returns,
/// and that the `ExtAwi` is not reallocated. The underlying memory should
/// never be written to.
#[doc(hidden)]
#[inline]
#[const_fn(cfg(feature = "const_support"))]
#[must_use]
pub fn as_ptr(&self) -> *const Digit {
self.internal_as_ref().as_ptr()
}
/// Returns a raw pointer to the underlying bit storage. The caller must
/// ensure that the `ExtAwi` outlives the pointer this function returns,
/// and that the `ExtAwi` is not reallocated.
#[doc(hidden)]
#[inline]
#[const_fn(cfg(feature = "const_support"))]
#[must_use]
pub fn as_mut_ptr(&mut self) -> *mut Digit {
self.internal_as_mut().as_mut_ptr()
}
#[doc(hidden)]
#[inline]
#[const_fn(cfg(feature = "const_support"))]
#[must_use]
pub const fn layout(&self) -> Layout {
layout(self.nzbw())
}
/// Creates an `ExtAwi` from copying a `Bits` reference. The same
/// functionality is provided by an `From<&Bits>` implementation for
/// `ExtAwi`.
pub fn from_bits(bits: &Bits) -> ExtAwi {
let mut tmp = ExtAwi::zero(bits.nzbw());
tmp.const_as_mut().copy_(bits).unwrap();
tmp
}
/// Zero-value construction with bitwidth `w`
pub fn zero(w: NonZeroUsize) -> Self {
// Safety: This satisfies `ExtAwi::from_raw_parts`
unsafe {
let ptr: *mut Digit = alloc_zeroed(layout(w)).cast();
ExtAwi::from_raw_parts(NonNull::new_unchecked(ptr), w)
}
}
/// Unsigned-maximum-value construction with bitwidth `w`
pub fn umax(w: NonZeroUsize) -> Self {
// Safety: This satisfies `ExtAwi::from_raw_parts`
let mut x = unsafe {
let ptr: *mut Digit = alloc(layout(w)).cast();
ptr.write_bytes(u8::MAX, total_digits(w).get());
ExtAwi::from_raw_parts(NonNull::new_unchecked(ptr), w)
};
x.const_as_mut().clear_unused_bits();
x
}
/// Signed-maximum-value construction with bitwidth `w`
pub fn imax(w: NonZeroUsize) -> Self {
let mut val = Self::umax(w);
*val.const_as_mut().last_mut() = (MAX >> 1) >> val.unused();
val
}
/// Signed-minimum-value construction with bitwidth `w`
pub fn imin(w: NonZeroUsize) -> Self {
let mut val = Self::zero(w);
*val.const_as_mut().last_mut() = (IDigit::MIN as Digit) >> val.unused();
val
}
/// Unsigned-one-value construction with bitwidth `w`
pub fn uone(w: NonZeroUsize) -> Self {
let mut val = Self::zero(w);
*val.const_as_mut().first_mut() = 1;
val
}
/// Used by `awint_macros` in avoiding a `NonZeroUsize` dependency
#[doc(hidden)]
pub fn panicking_zero(w: usize) -> Self {
Self::zero(NonZeroUsize::new(w).unwrap())
}
/// Used by `awint_macros` in avoiding a `NonZeroUsize` dependency
#[doc(hidden)]
pub fn panicking_umax(w: usize) -> Self {
Self::umax(NonZeroUsize::new(w).unwrap())
}
/// Used by `awint_macros` in avoiding a `NonZeroUsize` dependency
#[doc(hidden)]
pub fn panicking_imax(w: usize) -> Self {
Self::imax(NonZeroUsize::new(w).unwrap())
}
/// Used by `awint_macros` in avoiding a `NonZeroUsize` dependency
#[doc(hidden)]
pub fn panicking_imin(w: usize) -> Self {
Self::imin(NonZeroUsize::new(w).unwrap())
}
/// Used by `awint_macros` in avoiding a `NonZeroUsize` dependency
#[doc(hidden)]
pub fn panicking_uone(w: usize) -> Self {
Self::uone(NonZeroUsize::new(w).unwrap())
}
}
impl Drop for ExtAwi {
fn drop(&mut self) {
unsafe {
dealloc(self.as_mut_ptr().cast(), self.layout());
}
}
}
impl Clone for ExtAwi {
fn clone(&self) -> ExtAwi {
// Safety: The allocation is made according to the layout, digits are copied
// according to digit length, and the `ExtAwi` is constructed with bitwidth
unsafe {
let dst = alloc(self.layout()).cast();
ptr::copy_nonoverlapping(self.as_ptr(), dst, self.total_digits().get());
ExtAwi::from_raw_parts(NonNull::new_unchecked(dst), self.nzbw())
}
}
}
/// If `self` and `other` have unmatching bit widths, `false` will be returned.
impl PartialEq for ExtAwi {
fn eq(&self, rhs: &Self) -> bool {
self.as_ref() == rhs.as_ref()
}
}
/// If `self` and `other` have unmatching bit widths, `false` will be returned.
impl Eq for ExtAwi {}
#[cfg(feature = "zeroize_support")]
impl zeroize::Zeroize for ExtAwi {
fn zeroize(&mut self) {
self.as_mut().zeroize()
}
}
macro_rules! impl_fmt {
($($ty:ident)*) => {
$(
/// Forwards to the corresponding impl for `Bits`
impl fmt::$ty for ExtAwi {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
fmt::$ty::fmt(self.as_ref(), f)
}
}
)*
};
}
impl_fmt!(Debug Display LowerHex UpperHex Octal Binary);
impl Hash for ExtAwi {
fn hash<H: Hasher>(&self, state: &mut H) {
self.as_ref().hash(state);
}
}
impl Deref for ExtAwi {
type Target = Bits;
#[inline]
fn deref(&self) -> &Self::Target {
self.internal_as_ref()
}
}
impl DerefMut for ExtAwi {
#[inline]
fn deref_mut(&mut self) -> &mut Bits {
self.internal_as_mut()
}
}
impl Index<RangeFull> for ExtAwi {
type Output = Bits;
#[inline]
fn index(&self, _i: RangeFull) -> &Bits {
self
}
}
impl Borrow<Bits> for ExtAwi {
#[inline]
fn borrow(&self) -> &Bits {
self
}
}
impl AsRef<Bits> for ExtAwi {
#[inline]
fn as_ref(&self) -> &Bits {
self
}
}
impl IndexMut<RangeFull> for ExtAwi {
#[inline]
fn index_mut(&mut self, _i: RangeFull) -> &mut Bits {
self
}
}
impl BorrowMut<Bits> for ExtAwi {
#[inline]
fn borrow_mut(&mut self) -> &mut Bits {
self
}
}
impl AsMut<Bits> for ExtAwi {
#[inline]
fn as_mut(&mut self) -> &mut Bits {
self
}
}
// we unfortunately can't do something like `impl<B: Borrow<Bits>> From<B>`
// because specialization is not stabilized
/// Creates an `ExtAwi` from copying a `Bits` reference
impl From<&Bits> for ExtAwi {
fn from(bits: &Bits) -> ExtAwi {
let mut tmp = ExtAwi::zero(bits.nzbw());
tmp.const_as_mut().copy_(bits).unwrap();
tmp
}
}
/// Creates an `ExtAwi` from copying an `InlAwi`
impl<const BW: usize, const LEN: usize> From<InlAwi<BW, LEN>> for ExtAwi {
fn from(awi: InlAwi<BW, LEN>) -> ExtAwi {
let mut tmp = ExtAwi::zero(awi.nzbw());
tmp.const_as_mut().copy_(&awi).unwrap();
tmp
}
}
macro_rules! extawi_from_ty {
($($ty:ident $from:ident $assign:ident);*;) => {
$(
/// Creates an `ExtAwi` with the same bitwidth and bits as the integer
pub fn $from(x: $ty) -> Self {
let mut tmp = ExtAwi::zero(bw($ty::BITS as usize));
tmp.$assign(x);
tmp
}
)*
};
}
impl ExtAwi {
extawi_from_ty!(
u8 from_u8 u8_;
u16 from_u16 u16_;
u32 from_u32 u32_;
u64 from_u64 u64_;
u128 from_u128 u128_;
usize from_usize usize_;
i8 from_i8 i8_;
i16 from_i16 i16_;
i32 from_i32 i32_;
i64 from_i64 i64_;
i128 from_i128 i128_;
isize from_isize isize_;
);
/// Creates an `ExtAwi` with one bit set to this `bool`
pub fn from_bool(x: bool) -> Self {
let mut tmp = ExtAwi::zero(bw(1));
tmp.bool_(x);
tmp
}
/// Creates an `ExtAwi` with the same bitwidth and bits as the integer
pub fn from_digit(x: Digit) -> Self {
let mut tmp = ExtAwi::zero(bw(BITS));
tmp.digit_(x);
tmp
}
}
impl From<bool> for ExtAwi {
fn from(x: bool) -> ExtAwi {
let mut tmp = ExtAwi::zero(bw(1));
tmp.bool_(x);
tmp
}
}
macro_rules! extawi_from {
($($ty:ident, $assign:ident);*;) => {
$(
impl From<$ty> for ExtAwi {
fn from(x: $ty) -> Self {
let mut tmp = ExtAwi::zero(bw($ty::BITS as usize));
tmp.$assign(x);
tmp
}
}
)*
};
}
extawi_from!(
u8, u8_;
u16, u16_;
u32, u32_;
u64, u64_;
u128, u128_;
usize, usize_;
i8, i8_;
i16, i16_;
i32, i32_;
i64, i64_;
i128, i128_;
isize, isize_;
);