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#![no_std] #![cfg_attr(doc, feature(doc_cfg, external_doc))] #![cfg_attr(feature = "intrinsics", feature(core_intrinsics))] #![cfg_attr(doc, doc(include = "../README.md"))] #![feature( min_const_generics, specialization, allocator_api, nonnull_slice_from_raw_parts, const_nonnull_slice_from_raw_parts, slice_ptr_get, slice_ptr_len, const_slice_ptr_len )] #![cfg_attr(test, feature(maybe_uninit_slice))] #![allow(incomplete_features, clippy::must_use_candidate)] #[cfg(any(feature = "alloc", doc, test))] extern crate alloc; // pub mod stats; mod helper; #[macro_use] mod macros; // mod affix; mod callback_ref; mod chunk; mod fallback; mod null; mod proxy; pub mod region; pub mod stats; // mod segregate; use core::{ alloc::{AllocError, Layout}, ptr::NonNull, }; pub use self::{ callback_ref::CallbackRef, chunk::Chunk, fallback::Fallback, null::Null, proxy::Proxy, }; #[cfg(feature = "intrinsics")] mod intrinsics { pub use core::intrinsics::{assume, unlikely}; } #[cfg(not(feature = "intrinsics"))] mod intrinsics { #![allow(clippy::missing_const_for_fn, clippy::inline_always, unused)] #[inline(always)] pub fn unlikely(b: bool) -> bool { b } #[inline(always)] pub const unsafe fn assume(_: bool) {} } #[allow(unused_imports)] use crate::intrinsics::{assume, unlikely}; #[allow(non_snake_case)] mod SIZE {} /// Extends `AllocRef` for allocating or deallocating all memory at once. pub unsafe trait AllocateAll { /// Attempts to allocate all of the memory the allocator can provide. /// /// If the allocator is currently not managing any memory, then it returns all the memory /// available to the allocator. Subsequent are unlikely to succeed. /// /// On success, returns `[NonNull<[u8]>]` meeting the size and alignment guarantees of `layout`. /// /// The returned block may have a larger size than specified by `layout.size()`, and may or may /// not have its contents initialized. /// /// Also see [`AllocRef::alloc`] /// /// [`AllocRef::alloc`]: core::alloc::AllocRef::alloc /// /// # Errors /// /// Returning `Err` indicates that either memory is exhausted or `layout` does not meet /// allocators size or alignment constraints. /// /// Implementations are encouraged to return `Err` on memory exhaustion rather than panicking or /// aborting, but this is not a strict requirement. (Specifically: it is *legal* to implement /// this trait atop an underlying native allocation library that aborts on memory exhaustion.) /// /// Clients wishing to abort computation in response to an allocation error are encouraged to /// call the [`handle_alloc_error`] function, rather than directly invoking `panic!` or similar. /// /// [`handle_alloc_error`]: https://doc.rust-lang.org/alloc/alloc/fn.handle_alloc_error.html fn allocate_all(&self) -> Result<NonNull<[u8]>, AllocError>; /// Behaves like `alloc_all`, but also ensures that the returned memory is zero-initialized. /// /// Also see [`AllocRef::alloc_zeroed`] /// /// [`AllocRef::alloc_zeroed`]: core::alloc::AllocRef::alloc_zeroed /// /// # Errors /// /// Returning `Err` indicates that either memory is exhausted or `layout` does not meet /// allocators size or alignment constraints. /// /// Implementations are encouraged to return `Err` on memory exhaustion rather than panicking or /// aborting, but this is not a strict requirement. (Specifically: it is *legal* to implement /// this trait atop an underlying native allocation library that aborts on memory exhaustion.) /// /// Clients wishing to abort computation in response to an allocation error are encouraged to /// call the [`handle_alloc_error`] function, rather than directly invoking `panic!` or similar. /// /// [`handle_alloc_error`]: https://doc.rust-lang.org/alloc/alloc/fn.handle_alloc_error.html fn allocate_all_zeroed(&self) -> Result<NonNull<[u8]>, AllocError> { let ptr = self.allocate_all()?; // SAFETY: `allocate_all` returns a valid memory block unsafe { ptr.as_non_null_ptr().as_ptr().write_bytes(0, ptr.len()) } Ok(ptr) } /// Deallocates all the memory the allocator had allocated. fn deallocate_all(&self); /// Returns the total capacity available in this allocator. fn capacity(&self) -> usize; /// Returns the free capacity left for allocating. fn capacity_left(&self) -> usize; /// Returns if the allocator is currently not holding memory. fn is_empty(&self) -> bool { self.capacity() == self.capacity_left() } /// Returns if the allocator has no more capacity left. fn is_full(&self) -> bool { self.capacity_left() == 0 } } /// Extends `AllocRef` to support growing and shrinking in place. pub unsafe trait ReallocateInPlace { /// Attempts to extend the memory block. /// /// Returns the new actual size of the allocated memory. The pointer is suitable for holding /// data described by a new layout with `layout`’s alignment and a size given by `new_size`. /// To accomplish this, the allocator may extend the allocation referenced by `ptr` to fit the /// new layout. /// /// If this method returns `Err`, the allocator was not able to grow the memory without /// changing the pointer. The ownership of the memory block has not been transferred to /// this allocator, and the contents of the memory block are unaltered. /// /// # Safety /// /// * `ptr` must denote a block of memory [*currently allocated*] via this allocator. /// * `old_layout` must [*fit*] that block of memory (The `new_layout` argument need not fit it.). /// * `new_layout.size()` must be greater than or equal to `old_layout.size()`. /// /// [*currently allocated*]: https://doc.rust-lang.org/nightly/alloc/alloc/trait.AllocRef.html#currently-allocated-memory /// [*fit*]: https://doc.rust-lang.org/nightly/alloc/alloc/trait.AllocRef.html#memory-fitting /// /// # Errors /// /// Returns `Err` if the new layout does not meet the allocators size and alignment /// constraints of the allocator, or if growing otherwise fails. /// /// Implementations are encouraged to return `Err` on memory exhaustion rather than panicking or /// aborting, but this is not a strict requirement. (Specifically: it is *legal* to implement /// this trait atop an underlying native allocation library that aborts on memory exhaustion.) /// /// Clients wishing to abort computation in response to an allocation error are encouraged to /// call the [`handle_alloc_error`] function, rather than directly invoking `panic!` or similar. /// /// [`handle_alloc_error`]: https://doc.rust-lang.org/alloc/alloc/fn.handle_alloc_error.html unsafe fn grow_in_place( &self, ptr: NonNull<u8>, old_layout: Layout, new_layout: Layout, ) -> Result<usize, AllocError>; /// Behaves like `grow_in_place`, but also ensures that the new contents are set to zero before /// being returned. /// /// The memory block will contain the following contents after a successful call to /// `grow_zeroed`: /// * Bytes `0..old_layout.size()` are preserved from the original allocation. /// * Bytes `old_layout.size()..old_size` will either be preserved or zeroed, depending on /// the allocator implementation. `old_size` refers to the size of the memory block prior /// to the `grow_zeroed` call, which may be larger than the size that was originally /// requested when it was allocated. /// * Bytes `old_size..new_size` are zeroed. `new_size` refers to the size of the memory /// block returned by the `grow_zeroed` call. /// /// # Safety /// /// * `ptr` must denote a block of memory [*currently allocated*] via this allocator. /// * `old_layout` must [*fit*] that block of memory (The `new_layout` argument need not fit it.). /// * `new_layout.size()` must be greater than or equal to `old_layout.size()`. /// /// [*currently allocated*]: https://doc.rust-lang.org/nightly/alloc/alloc/trait.AllocRef.html#currently-allocated-memory /// [*fit*]: https://doc.rust-lang.org/nightly/alloc/alloc/trait.AllocRef.html#memory-fitting /// /// # Errors /// /// Returns `Err` if the new layout does not meet the allocators size and alignment /// constraints of the allocator, or if growing otherwise fails. /// /// Implementations are encouraged to return `Err` on memory exhaustion rather than panicking or /// aborting, but this is not a strict requirement. (Specifically: it is *legal* to implement /// this trait atop an underlying native allocation library that aborts on memory exhaustion.) /// /// Clients wishing to abort computation in response to an allocation error are encouraged to /// call the [`handle_alloc_error`] function, rather than directly invoking `panic!` or similar. /// /// [`handle_alloc_error`]: https://doc.rust-lang.org/alloc/alloc/fn.handle_alloc_error.html unsafe fn grow_in_place_zeroed( &self, ptr: NonNull<u8>, old_layout: Layout, new_layout: Layout, ) -> Result<usize, AllocError>; /// Attempts to shrink the memory block. /// /// Returns the new actual size of the allocated memory. The pointer is suitable for holding /// data described by a new layout with `layout`’s alignment and a size given by `new_size`. /// To accomplish this, the allocator may extend the allocation referenced by `ptr` to fit the /// new layout. /// /// If this method returns `Err`, the allocator was not able to shrink the memory without /// changing the pointer. The ownership of the memory block has not been transferred to /// this allocator, and the contents of the memory block are unaltered. /// /// # Safety /// /// * `ptr` must denote a block of memory [*currently allocated*] via this allocator. /// * `old_layout` must [*fit*] that block of memory (The `new_layout` argument need not fit it.). /// * `new_layout.size()` must be smaller than or equal to `old_layout.size()`. /// /// [*currently allocated*]: https://doc.rust-lang.org/nightly/alloc/alloc/trait.AllocRef.html#currently-allocated-memory /// [*fit*]: https://doc.rust-lang.org/nightly/alloc/alloc/trait.AllocRef.html#memory-fitting /// /// # Errors /// /// Returns `Err` if the new layout does not meet the allocator's size and alignment /// constraints of the allocator, or if shrinking otherwise fails. /// /// Implementations are encouraged to return `Err` on memory exhaustion rather than panicking or /// aborting, but this is not a strict requirement. (Specifically: it is *legal* to implement /// this trait atop an underlying native allocation library that aborts on memory exhaustion.) /// /// Clients wishing to abort computation in response to an allocation error are encouraged to /// call the [`handle_alloc_error`] function, rather than directly invoking `panic!` or similar. /// /// [`handle_alloc_error`]: https://doc.rust-lang.org/alloc/alloc/fn.handle_alloc_error.html unsafe fn shrink_in_place( &self, ptr: NonNull<u8>, old_layout: Layout, new_layout: Layout, ) -> Result<usize, AllocError>; } /// Trait to determine if a given memory block is owned by an allocator. pub trait Owns { /// Returns if the allocator *owns* the passed memory. fn owns(&self, ptr: NonNull<[u8]>) -> bool; } macro_rules! impl_traits { ($(#[$meta:meta])* $ty:ty ) => { $(#[$meta])* unsafe impl<A> AllocateAll for $ty where A: AllocateAll + ?Sized, { fn allocate_all(&self) -> Result<NonNull<[u8]>, AllocError> { (**self).allocate_all() } fn allocate_all_zeroed(&self) -> Result<NonNull<[u8]>, AllocError> { (**self).allocate_all_zeroed() } fn deallocate_all(&self) { (**self).deallocate_all() } fn capacity(&self) -> usize { (**self).capacity() } fn capacity_left(&self) -> usize { (**self).capacity_left() } fn is_empty(&self) -> bool { (**self).is_empty() } fn is_full(&self) -> bool { (**self).is_full() } } $(#[$meta])* unsafe impl<A> ReallocateInPlace for $ty where A: ReallocateInPlace + ?Sized, { unsafe fn grow_in_place( &self, ptr: NonNull<u8>, old_layout: Layout, new_layout: Layout, ) -> Result<usize, AllocError> { (**self).grow_in_place(ptr, old_layout, new_layout) } unsafe fn grow_in_place_zeroed( &self, ptr: NonNull<u8>, old_layout: Layout, new_layout: Layout, ) -> Result<usize, AllocError> { (**self).grow_in_place_zeroed(ptr, old_layout, new_layout) } unsafe fn shrink_in_place( &self, ptr: NonNull<u8>, old_layout: Layout, new_layout: Layout, ) -> Result<usize, AllocError> { (**self).shrink_in_place(ptr, old_layout, new_layout) } } $(#[$meta])* impl<A> Owns for $ty where A: Owns + ?Sized, { fn owns(&self, ptr: NonNull<[u8]>) -> bool { (**self).owns(ptr) } } }; } impl_traits!(&A); #[cfg(any(doc, feature = "alloc"))] impl_traits!(#[cfg_attr(doc, doc(cfg(feature = "alloc")))] alloc::boxed::Box<A>); #[cfg(any(doc, feature = "alloc"))] impl_traits!(#[cfg_attr(doc, doc(cfg(feature = "alloc")))] alloc::rc::Rc<A>); #[cfg(any(doc, feature = "alloc"))] impl_traits!(#[cfg_attr(doc, doc(cfg(feature = "alloc")))] alloc::sync::Arc<A>); #[track_caller] #[inline] fn check_dealloc_precondition(ptr: NonNull<u8>, layout: Layout) { debug_assert!( ptr.as_ptr() as usize >= layout.align(), "`ptr` allocated with the same alignment as `layout.align()`, expected {} >= {}", ptr.as_ptr() as usize, layout.align() ); } #[track_caller] #[inline] fn check_grow_precondition(ptr: NonNull<u8>, old_layout: Layout, new_layout: Layout) { debug_assert!( ptr.as_ptr() as usize >= old_layout.align(), "`ptr` allocated with the same alignment as `old_layout.align()`, expected {} >= {}", ptr.as_ptr() as usize, old_layout.align() ); debug_assert!( new_layout.size() >= old_layout.size(), "`new_layout.size()` must be greater than or equal to `old_layout.size()`, expected {} >= \ {}", new_layout.size(), old_layout.size() ); } #[track_caller] #[inline] fn check_shrink_precondition(ptr: NonNull<u8>, old_layout: Layout, new_layout: Layout) { debug_assert!( ptr.as_ptr() as usize >= old_layout.align(), "`ptr` allocated with the same alignment as `old_layout.align()`, expected {} >= {}", ptr.as_ptr() as usize, old_layout.align() ); debug_assert!( new_layout.size() <= old_layout.size(), "`new_layout.size()` must be smaller than or equal to `old_layout.size()`, expected {} <= \ {}", new_layout.size(), old_layout.size() ); }