| use super::*; |
| use crate::cmp::Ordering::{self, Equal, Greater, Less}; |
| use crate::intrinsics; |
| |
| // ignore-tidy-undocumented-unsafe |
| |
| #[lang = "mut_ptr"] |
| impl<T: ?Sized> *mut T { |
| /// Returns `true` if the pointer is null. |
| /// |
| /// Note that unsized types have many possible null pointers, as only the |
| /// raw data pointer is considered, not their length, vtable, etc. |
| /// Therefore, two pointers that are null may still not compare equal to |
| /// each other. |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let mut s = [1, 2, 3]; |
| /// let ptr: *mut u32 = s.as_mut_ptr(); |
| /// assert!(!ptr.is_null()); |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| #[inline] |
| pub fn is_null(self) -> bool { |
| // Compare via a cast to a thin pointer, so fat pointers are only |
| // considering their "data" part for null-ness. |
| (self as *mut u8) == null_mut() |
| } |
| |
| /// Casts to a pointer of another type. |
| #[stable(feature = "ptr_cast", since = "1.38.0")] |
| #[rustc_const_stable(feature = "const_ptr_cast", since = "1.38.0")] |
| #[inline] |
| pub const fn cast<U>(self) -> *mut U { |
| self as _ |
| } |
| |
| /// Returns `None` if the pointer is null, or else returns a reference to |
| /// the value wrapped in `Some`. |
| /// |
| /// # Safety |
| /// |
| /// While this method and its mutable counterpart are useful for |
| /// null-safety, it is important to note that this is still an unsafe |
| /// operation because the returned value could be pointing to invalid |
| /// memory. |
| /// |
| /// When calling this method, you have to ensure that if the pointer is |
| /// non-NULL, then it is properly aligned, dereferencable (for the whole |
| /// size of `T`) and points to an initialized instance of `T`. This applies |
| /// even if the result of this method is unused! |
| /// (The part about being initialized is not yet fully decided, but until |
| /// it is, the only safe approach is to ensure that they are indeed initialized.) |
| /// |
| /// Additionally, the lifetime `'a` returned is arbitrarily chosen and does |
| /// not necessarily reflect the actual lifetime of the data. It is up to the |
| /// caller to ensure that for the duration of this lifetime, the memory this |
| /// pointer points to does not get written to outside of `UnsafeCell<U>`. |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let ptr: *mut u8 = &mut 10u8 as *mut u8; |
| /// |
| /// unsafe { |
| /// if let Some(val_back) = ptr.as_ref() { |
| /// println!("We got back the value: {}!", val_back); |
| /// } |
| /// } |
| /// ``` |
| /// |
| /// # Null-unchecked version |
| /// |
| /// If you are sure the pointer can never be null and are looking for some kind of |
| /// `as_ref_unchecked` that returns the `&T` instead of `Option<&T>`, know that you can |
| /// dereference the pointer directly. |
| /// |
| /// ``` |
| /// let ptr: *mut u8 = &mut 10u8 as *mut u8; |
| /// |
| /// unsafe { |
| /// let val_back = &*ptr; |
| /// println!("We got back the value: {}!", val_back); |
| /// } |
| /// ``` |
| #[stable(feature = "ptr_as_ref", since = "1.9.0")] |
| #[inline] |
| pub unsafe fn as_ref<'a>(self) -> Option<&'a T> { |
| if self.is_null() { None } else { Some(&*self) } |
| } |
| |
| /// Calculates the offset from a pointer. |
| /// |
| /// `count` is in units of T; e.g., a `count` of 3 represents a pointer |
| /// offset of `3 * size_of::<T>()` bytes. |
| /// |
| /// # Safety |
| /// |
| /// If any of the following conditions are violated, the result is Undefined |
| /// Behavior: |
| /// |
| /// * Both the starting and resulting pointer must be either in bounds or one |
| /// byte past the end of the same allocated object. Note that in Rust, |
| /// every (stack-allocated) variable is considered a separate allocated object. |
| /// |
| /// * The computed offset, **in bytes**, cannot overflow an `isize`. |
| /// |
| /// * The offset being in bounds cannot rely on "wrapping around" the address |
| /// space. That is, the infinite-precision sum, **in bytes** must fit in a usize. |
| /// |
| /// The compiler and standard library generally tries to ensure allocations |
| /// never reach a size where an offset is a concern. For instance, `Vec` |
| /// and `Box` ensure they never allocate more than `isize::MAX` bytes, so |
| /// `vec.as_ptr().add(vec.len())` is always safe. |
| /// |
| /// Most platforms fundamentally can't even construct such an allocation. |
| /// For instance, no known 64-bit platform can ever serve a request |
| /// for 2<sup>63</sup> bytes due to page-table limitations or splitting the address space. |
| /// However, some 32-bit and 16-bit platforms may successfully serve a request for |
| /// more than `isize::MAX` bytes with things like Physical Address |
| /// Extension. As such, memory acquired directly from allocators or memory |
| /// mapped files *may* be too large to handle with this function. |
| /// |
| /// Consider using [`wrapping_offset`] instead if these constraints are |
| /// difficult to satisfy. The only advantage of this method is that it |
| /// enables more aggressive compiler optimizations. |
| /// |
| /// [`wrapping_offset`]: #method.wrapping_offset |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let mut s = [1, 2, 3]; |
| /// let ptr: *mut u32 = s.as_mut_ptr(); |
| /// |
| /// unsafe { |
| /// println!("{}", *ptr.offset(1)); |
| /// println!("{}", *ptr.offset(2)); |
| /// } |
| /// ``` |
| #[stable(feature = "rust1", since = "1.0.0")] |
| #[inline] |
| pub unsafe fn offset(self, count: isize) -> *mut T |
| where |
| T: Sized, |
| { |
| intrinsics::offset(self, count) as *mut T |
| } |
| |
| /// Calculates the offset from a pointer using wrapping arithmetic. |
| /// `count` is in units of T; e.g., a `count` of 3 represents a pointer |
| /// offset of `3 * size_of::<T>()` bytes. |
| /// |
| /// # Safety |
| /// |
| /// The resulting pointer does not need to be in bounds, but it is |
| /// potentially hazardous to dereference (which requires `unsafe`). |
| /// |
| /// In particular, the resulting pointer remains attached to the same allocated |
| /// object that `self` points to. It may *not* be used to access a |
| /// different allocated object. Note that in Rust, |
| /// every (stack-allocated) variable is considered a separate allocated object. |
| /// |
| /// In other words, `x.wrapping_offset(y.wrapping_offset_from(x))` is |
| /// *not* the same as `y`, and dereferencing it is undefined behavior |
| /// unless `x` and `y` point into the same allocated object. |
| /// |
| /// Compared to [`offset`], this method basically delays the requirement of staying |
| /// within the same allocated object: [`offset`] is immediate Undefined Behavior when |
| /// crossing object boundaries; `wrapping_offset` produces a pointer but still leads |
| /// to Undefined Behavior if that pointer is dereferenced. [`offset`] can be optimized |
| /// better and is thus preferrable in performance-sensitive code. |
| /// |
| /// If you need to cross object boundaries, cast the pointer to an integer and |
| /// do the arithmetic there. |
| /// |
| /// [`offset`]: #method.offset |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// // Iterate using a raw pointer in increments of two elements |
| /// let mut data = [1u8, 2, 3, 4, 5]; |
| /// let mut ptr: *mut u8 = data.as_mut_ptr(); |
| /// let step = 2; |
| /// let end_rounded_up = ptr.wrapping_offset(6); |
| /// |
| /// while ptr != end_rounded_up { |
| /// unsafe { |
| /// *ptr = 0; |
| /// } |
| /// ptr = ptr.wrapping_offset(step); |
| /// } |
| /// assert_eq!(&data, &[0, 2, 0, 4, 0]); |
| /// ``` |
| #[stable(feature = "ptr_wrapping_offset", since = "1.16.0")] |
| #[inline] |
| pub fn wrapping_offset(self, count: isize) -> *mut T |
| where |
| T: Sized, |
| { |
| unsafe { intrinsics::arith_offset(self, count) as *mut T } |
| } |
| |
| /// Returns `None` if the pointer is null, or else returns a mutable |
| /// reference to the value wrapped in `Some`. |
| /// |
| /// # Safety |
| /// |
| /// As with [`as_ref`], this is unsafe because it cannot verify the validity |
| /// of the returned pointer, nor can it ensure that the lifetime `'a` |
| /// returned is indeed a valid lifetime for the contained data. |
| /// |
| /// When calling this method, you have to ensure that *either* the pointer is NULL *or* |
| /// all of the following is true: |
| /// - it is properly aligned |
| /// - it must point to an initialized instance of T; in particular, the pointer must be |
| /// "dereferencable" in the sense defined [here]. |
| /// |
| /// This applies even if the result of this method is unused! |
| /// (The part about being initialized is not yet fully decided, but until |
| /// it is the only safe approach is to ensure that they are indeed initialized.) |
| /// |
| /// Additionally, the lifetime `'a` returned is arbitrarily chosen and does |
| /// not necessarily reflect the actual lifetime of the data. *You* must enforce |
| /// Rust's aliasing rules. In particular, for the duration of this lifetime, |
| /// the memory this pointer points to must not get accessed (read or written) |
| /// through any other pointer. |
| /// |
| /// [here]: crate::ptr#safety |
| /// [`as_ref`]: #method.as_ref |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let mut s = [1, 2, 3]; |
| /// let ptr: *mut u32 = s.as_mut_ptr(); |
| /// let first_value = unsafe { ptr.as_mut().unwrap() }; |
| /// *first_value = 4; |
| /// println!("{:?}", s); // It'll print: "[4, 2, 3]". |
| /// ``` |
| #[stable(feature = "ptr_as_ref", since = "1.9.0")] |
| #[inline] |
| pub unsafe fn as_mut<'a>(self) -> Option<&'a mut T> { |
| if self.is_null() { None } else { Some(&mut *self) } |
| } |
| |
| /// Calculates the distance between two pointers. The returned value is in |
| /// units of T: the distance in bytes is divided by `mem::size_of::<T>()`. |
| /// |
| /// This function is the inverse of [`offset`]. |
| /// |
| /// [`offset`]: #method.offset-1 |
| /// [`wrapping_offset_from`]: #method.wrapping_offset_from-1 |
| /// |
| /// # Safety |
| /// |
| /// If any of the following conditions are violated, the result is Undefined |
| /// Behavior: |
| /// |
| /// * Both the starting and other pointer must be either in bounds or one |
| /// byte past the end of the same allocated object. Note that in Rust, |
| /// every (stack-allocated) variable is considered a separate allocated object. |
| /// |
| /// * The distance between the pointers, **in bytes**, cannot overflow an `isize`. |
| /// |
| /// * The distance between the pointers, in bytes, must be an exact multiple |
| /// of the size of `T`. |
| /// |
| /// * The distance being in bounds cannot rely on "wrapping around" the address space. |
| /// |
| /// The compiler and standard library generally try to ensure allocations |
| /// never reach a size where an offset is a concern. For instance, `Vec` |
| /// and `Box` ensure they never allocate more than `isize::MAX` bytes, so |
| /// `ptr_into_vec.offset_from(vec.as_ptr())` is always safe. |
| /// |
| /// Most platforms fundamentally can't even construct such an allocation. |
| /// For instance, no known 64-bit platform can ever serve a request |
| /// for 2<sup>63</sup> bytes due to page-table limitations or splitting the address space. |
| /// However, some 32-bit and 16-bit platforms may successfully serve a request for |
| /// more than `isize::MAX` bytes with things like Physical Address |
| /// Extension. As such, memory acquired directly from allocators or memory |
| /// mapped files *may* be too large to handle with this function. |
| /// |
| /// Consider using [`wrapping_offset_from`] instead if these constraints are |
| /// difficult to satisfy. The only advantage of this method is that it |
| /// enables more aggressive compiler optimizations. |
| /// |
| /// # Panics |
| /// |
| /// This function panics if `T` is a Zero-Sized Type ("ZST"). |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// #![feature(ptr_offset_from)] |
| /// |
| /// let mut a = [0; 5]; |
| /// let ptr1: *mut i32 = &mut a[1]; |
| /// let ptr2: *mut i32 = &mut a[3]; |
| /// unsafe { |
| /// assert_eq!(ptr2.offset_from(ptr1), 2); |
| /// assert_eq!(ptr1.offset_from(ptr2), -2); |
| /// assert_eq!(ptr1.offset(2), ptr2); |
| /// assert_eq!(ptr2.offset(-2), ptr1); |
| /// } |
| /// ``` |
| #[unstable(feature = "ptr_offset_from", issue = "41079")] |
| #[rustc_const_unstable(feature = "const_ptr_offset_from", issue = "41079")] |
| #[inline] |
| pub const unsafe fn offset_from(self, origin: *const T) -> isize |
| where |
| T: Sized, |
| { |
| (self as *const T).offset_from(origin) |
| } |
| |
| /// Calculates the distance between two pointers. The returned value is in |
| /// units of T: the distance in bytes is divided by `mem::size_of::<T>()`. |
| /// |
| /// If the address different between the two pointers is not a multiple of |
| /// `mem::size_of::<T>()` then the result of the division is rounded towards |
| /// zero. |
| /// |
| /// Though this method is safe for any two pointers, note that its result |
| /// will be mostly useless if the two pointers aren't into the same allocated |
| /// object, for example if they point to two different local variables. |
| /// |
| /// # Panics |
| /// |
| /// This function panics if `T` is a zero-sized type. |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// #![feature(ptr_wrapping_offset_from)] |
| /// |
| /// let mut a = [0; 5]; |
| /// let ptr1: *mut i32 = &mut a[1]; |
| /// let ptr2: *mut i32 = &mut a[3]; |
| /// assert_eq!(ptr2.wrapping_offset_from(ptr1), 2); |
| /// assert_eq!(ptr1.wrapping_offset_from(ptr2), -2); |
| /// assert_eq!(ptr1.wrapping_offset(2), ptr2); |
| /// assert_eq!(ptr2.wrapping_offset(-2), ptr1); |
| /// |
| /// let ptr1: *mut i32 = 3 as _; |
| /// let ptr2: *mut i32 = 13 as _; |
| /// assert_eq!(ptr2.wrapping_offset_from(ptr1), 2); |
| /// ``` |
| #[unstable(feature = "ptr_wrapping_offset_from", issue = "41079")] |
| #[inline] |
| pub fn wrapping_offset_from(self, origin: *const T) -> isize |
| where |
| T: Sized, |
| { |
| (self as *const T).wrapping_offset_from(origin) |
| } |
| |
| /// Calculates the offset from a pointer (convenience for `.offset(count as isize)`). |
| /// |
| /// `count` is in units of T; e.g., a `count` of 3 represents a pointer |
| /// offset of `3 * size_of::<T>()` bytes. |
| /// |
| /// # Safety |
| /// |
| /// If any of the following conditions are violated, the result is Undefined |
| /// Behavior: |
| /// |
| /// * Both the starting and resulting pointer must be either in bounds or one |
| /// byte past the end of the same allocated object. Note that in Rust, |
| /// every (stack-allocated) variable is considered a separate allocated object. |
| /// |
| /// * The computed offset, **in bytes**, cannot overflow an `isize`. |
| /// |
| /// * The offset being in bounds cannot rely on "wrapping around" the address |
| /// space. That is, the infinite-precision sum must fit in a `usize`. |
| /// |
| /// The compiler and standard library generally tries to ensure allocations |
| /// never reach a size where an offset is a concern. For instance, `Vec` |
| /// and `Box` ensure they never allocate more than `isize::MAX` bytes, so |
| /// `vec.as_ptr().add(vec.len())` is always safe. |
| /// |
| /// Most platforms fundamentally can't even construct such an allocation. |
| /// For instance, no known 64-bit platform can ever serve a request |
| /// for 2<sup>63</sup> bytes due to page-table limitations or splitting the address space. |
| /// However, some 32-bit and 16-bit platforms may successfully serve a request for |
| /// more than `isize::MAX` bytes with things like Physical Address |
| /// Extension. As such, memory acquired directly from allocators or memory |
| /// mapped files *may* be too large to handle with this function. |
| /// |
| /// Consider using [`wrapping_add`] instead if these constraints are |
| /// difficult to satisfy. The only advantage of this method is that it |
| /// enables more aggressive compiler optimizations. |
| /// |
| /// [`wrapping_add`]: #method.wrapping_add |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let s: &str = "123"; |
| /// let ptr: *const u8 = s.as_ptr(); |
| /// |
| /// unsafe { |
| /// println!("{}", *ptr.add(1) as char); |
| /// println!("{}", *ptr.add(2) as char); |
| /// } |
| /// ``` |
| #[stable(feature = "pointer_methods", since = "1.26.0")] |
| #[inline] |
| pub unsafe fn add(self, count: usize) -> Self |
| where |
| T: Sized, |
| { |
| self.offset(count as isize) |
| } |
| |
| /// Calculates the offset from a pointer (convenience for |
| /// `.offset((count as isize).wrapping_neg())`). |
| /// |
| /// `count` is in units of T; e.g., a `count` of 3 represents a pointer |
| /// offset of `3 * size_of::<T>()` bytes. |
| /// |
| /// # Safety |
| /// |
| /// If any of the following conditions are violated, the result is Undefined |
| /// Behavior: |
| /// |
| /// * Both the starting and resulting pointer must be either in bounds or one |
| /// byte past the end of the same allocated object. Note that in Rust, |
| /// every (stack-allocated) variable is considered a separate allocated object. |
| /// |
| /// * The computed offset cannot exceed `isize::MAX` **bytes**. |
| /// |
| /// * The offset being in bounds cannot rely on "wrapping around" the address |
| /// space. That is, the infinite-precision sum must fit in a usize. |
| /// |
| /// The compiler and standard library generally tries to ensure allocations |
| /// never reach a size where an offset is a concern. For instance, `Vec` |
| /// and `Box` ensure they never allocate more than `isize::MAX` bytes, so |
| /// `vec.as_ptr().add(vec.len()).sub(vec.len())` is always safe. |
| /// |
| /// Most platforms fundamentally can't even construct such an allocation. |
| /// For instance, no known 64-bit platform can ever serve a request |
| /// for 2<sup>63</sup> bytes due to page-table limitations or splitting the address space. |
| /// However, some 32-bit and 16-bit platforms may successfully serve a request for |
| /// more than `isize::MAX` bytes with things like Physical Address |
| /// Extension. As such, memory acquired directly from allocators or memory |
| /// mapped files *may* be too large to handle with this function. |
| /// |
| /// Consider using [`wrapping_sub`] instead if these constraints are |
| /// difficult to satisfy. The only advantage of this method is that it |
| /// enables more aggressive compiler optimizations. |
| /// |
| /// [`wrapping_sub`]: #method.wrapping_sub |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// let s: &str = "123"; |
| /// |
| /// unsafe { |
| /// let end: *const u8 = s.as_ptr().add(3); |
| /// println!("{}", *end.sub(1) as char); |
| /// println!("{}", *end.sub(2) as char); |
| /// } |
| /// ``` |
| #[stable(feature = "pointer_methods", since = "1.26.0")] |
| #[inline] |
| pub unsafe fn sub(self, count: usize) -> Self |
| where |
| T: Sized, |
| { |
| self.offset((count as isize).wrapping_neg()) |
| } |
| |
| /// Calculates the offset from a pointer using wrapping arithmetic. |
| /// (convenience for `.wrapping_offset(count as isize)`) |
| /// |
| /// `count` is in units of T; e.g., a `count` of 3 represents a pointer |
| /// offset of `3 * size_of::<T>()` bytes. |
| /// |
| /// # Safety |
| /// |
| /// The resulting pointer does not need to be in bounds, but it is |
| /// potentially hazardous to dereference (which requires `unsafe`). |
| /// |
| /// In particular, the resulting pointer remains attached to the same allocated |
| /// object that `self` points to. It may *not* be used to access a |
| /// different allocated object. Note that in Rust, |
| /// every (stack-allocated) variable is considered a separate allocated object. |
| /// |
| /// Compared to [`add`], this method basically delays the requirement of staying |
| /// within the same allocated object: [`add`] is immediate Undefined Behavior when |
| /// crossing object boundaries; `wrapping_add` produces a pointer but still leads |
| /// to Undefined Behavior if that pointer is dereferenced. [`add`] can be optimized |
| /// better and is thus preferrable in performance-sensitive code. |
| /// |
| /// If you need to cross object boundaries, cast the pointer to an integer and |
| /// do the arithmetic there. |
| /// |
| /// [`add`]: #method.add |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// // Iterate using a raw pointer in increments of two elements |
| /// let data = [1u8, 2, 3, 4, 5]; |
| /// let mut ptr: *const u8 = data.as_ptr(); |
| /// let step = 2; |
| /// let end_rounded_up = ptr.wrapping_add(6); |
| /// |
| /// // This loop prints "1, 3, 5, " |
| /// while ptr != end_rounded_up { |
| /// unsafe { |
| /// print!("{}, ", *ptr); |
| /// } |
| /// ptr = ptr.wrapping_add(step); |
| /// } |
| /// ``` |
| #[stable(feature = "pointer_methods", since = "1.26.0")] |
| #[inline] |
| pub fn wrapping_add(self, count: usize) -> Self |
| where |
| T: Sized, |
| { |
| self.wrapping_offset(count as isize) |
| } |
| |
| /// Calculates the offset from a pointer using wrapping arithmetic. |
| /// (convenience for `.wrapping_offset((count as isize).wrapping_sub())`) |
| /// |
| /// `count` is in units of T; e.g., a `count` of 3 represents a pointer |
| /// offset of `3 * size_of::<T>()` bytes. |
| /// |
| /// # Safety |
| /// |
| /// The resulting pointer does not need to be in bounds, but it is |
| /// potentially hazardous to dereference (which requires `unsafe`). |
| /// |
| /// In particular, the resulting pointer remains attached to the same allocated |
| /// object that `self` points to. It may *not* be used to access a |
| /// different allocated object. Note that in Rust, |
| /// every (stack-allocated) variable is considered a separate allocated object. |
| /// |
| /// Compared to [`sub`], this method basically delays the requirement of staying |
| /// within the same allocated object: [`sub`] is immediate Undefined Behavior when |
| /// crossing object boundaries; `wrapping_sub` produces a pointer but still leads |
| /// to Undefined Behavior if that pointer is dereferenced. [`sub`] can be optimized |
| /// better and is thus preferrable in performance-sensitive code. |
| /// |
| /// If you need to cross object boundaries, cast the pointer to an integer and |
| /// do the arithmetic there. |
| /// |
| /// [`sub`]: #method.sub |
| /// |
| /// # Examples |
| /// |
| /// Basic usage: |
| /// |
| /// ``` |
| /// // Iterate using a raw pointer in increments of two elements (backwards) |
| /// let data = [1u8, 2, 3, 4, 5]; |
| /// let mut ptr: *const u8 = data.as_ptr(); |
| /// let start_rounded_down = ptr.wrapping_sub(2); |
| /// ptr = ptr.wrapping_add(4); |
| /// let step = 2; |
| /// // This loop prints "5, 3, 1, " |
| /// while ptr != start_rounded_down { |
| /// unsafe { |
| /// print!("{}, ", *ptr); |
| /// } |
| /// ptr = ptr.wrapping_sub(step); |
| /// } |
| /// ``` |
| #[stable(feature = "pointer_methods", since = "1.26.0")] |
| #[inline] |
| pub fn wrapping_sub(self, count: usize) -> Self |
| where |
| T: Sized, |
| { |
| self.wrapping_offset((count as isize).wrapping_neg()) |
| } |
| |
| /// Reads the value from `self` without moving it. This leaves the |
| /// memory in `self` unchanged. |
| /// |
| /// See [`ptr::read`] for safety concerns and examples. |
| /// |
| /// [`ptr::read`]: ./ptr/fn.read.html |
| #[stable(feature = "pointer_methods", since = "1.26.0")] |
| #[inline] |
| pub unsafe fn read(self) -> T |
| where |
| T: Sized, |
| { |
| read(self) |
| } |
| |
| /// Performs a volatile read of the value from `self` without moving it. This |
| /// leaves the memory in `self` unchanged. |
| /// |
| /// Volatile operations are intended to act on I/O memory, and are guaranteed |
| /// to not be elided or reordered by the compiler across other volatile |
| /// operations. |
| /// |
| /// See [`ptr::read_volatile`] for safety concerns and examples. |
| /// |
| /// [`ptr::read_volatile`]: ./ptr/fn.read_volatile.html |
| #[stable(feature = "pointer_methods", since = "1.26.0")] |
| #[inline] |
| pub unsafe fn read_volatile(self) -> T |
| where |
| T: Sized, |
| { |
| read_volatile(self) |
| } |
| |
| /// Reads the value from `self` without moving it. This leaves the |
| /// memory in `self` unchanged. |
| /// |
| /// Unlike `read`, the pointer may be unaligned. |
| /// |
| /// See [`ptr::read_unaligned`] for safety concerns and examples. |
| /// |
| /// [`ptr::read_unaligned`]: ./ptr/fn.read_unaligned.html |
| #[stable(feature = "pointer_methods", since = "1.26.0")] |
| #[inline] |
| pub unsafe fn read_unaligned(self) -> T |
| where |
| T: Sized, |
| { |
| read_unaligned(self) |
| } |
| |
| /// Copies `count * size_of<T>` bytes from `self` to `dest`. The source |
| /// and destination may overlap. |
| /// |
| /// NOTE: this has the *same* argument order as [`ptr::copy`]. |
| /// |
| /// See [`ptr::copy`] for safety concerns and examples. |
| /// |
| /// [`ptr::copy`]: ./ptr/fn.copy.html |
| #[stable(feature = "pointer_methods", since = "1.26.0")] |
| #[inline] |
| pub unsafe fn copy_to(self, dest: *mut T, count: usize) |
| where |
| T: Sized, |
| { |
| copy(self, dest, count) |
| } |
| |
| /// Copies `count * size_of<T>` bytes from `self` to `dest`. The source |
| /// and destination may *not* overlap. |
| /// |
| /// NOTE: this has the *same* argument order as [`ptr::copy_nonoverlapping`]. |
| /// |
| /// See [`ptr::copy_nonoverlapping`] for safety concerns and examples. |
| /// |
| /// [`ptr::copy_nonoverlapping`]: ./ptr/fn.copy_nonoverlapping.html |
| #[stable(feature = "pointer_methods", since = "1.26.0")] |
| #[inline] |
| pub unsafe fn copy_to_nonoverlapping(self, dest: *mut T, count: usize) |
| where |
| T: Sized, |
| { |
| copy_nonoverlapping(self, dest, count) |
| } |
| |
| /// Copies `count * size_of<T>` bytes from `src` to `self`. The source |
| /// and destination may overlap. |
| /// |
| /// NOTE: this has the *opposite* argument order of [`ptr::copy`]. |
| /// |
| /// See [`ptr::copy`] for safety concerns and examples. |
| /// |
| /// [`ptr::copy`]: ./ptr/fn.copy.html |
| #[stable(feature = "pointer_methods", since = "1.26.0")] |
| #[inline] |
| pub unsafe fn copy_from(self, src: *const T, count: usize) |
| where |
| T: Sized, |
| { |
| copy(src, self, count) |
| } |
| |
| /// Copies `count * size_of<T>` bytes from `src` to `self`. The source |
| /// and destination may *not* overlap. |
| /// |
| /// NOTE: this has the *opposite* argument order of [`ptr::copy_nonoverlapping`]. |
| /// |
| /// See [`ptr::copy_nonoverlapping`] for safety concerns and examples. |
| /// |
| /// [`ptr::copy_nonoverlapping`]: ./ptr/fn.copy_nonoverlapping.html |
| #[stable(feature = "pointer_methods", since = "1.26.0")] |
| #[inline] |
| pub unsafe fn copy_from_nonoverlapping(self, src: *const T, count: usize) |
| where |
| T: Sized, |
| { |
| copy_nonoverlapping(src, self, count) |
| } |
| |
| /// Executes the destructor (if any) of the pointed-to value. |
| /// |
| /// See [`ptr::drop_in_place`] for safety concerns and examples. |
| /// |
| /// [`ptr::drop_in_place`]: ./ptr/fn.drop_in_place.html |
| #[stable(feature = "pointer_methods", since = "1.26.0")] |
| #[inline] |
| pub unsafe fn drop_in_place(self) { |
| drop_in_place(self) |
| } |
| |
| /// Overwrites a memory location with the given value without reading or |
| /// dropping the old value. |
| /// |
| /// See [`ptr::write`] for safety concerns and examples. |
| /// |
| /// [`ptr::write`]: ./ptr/fn.write.html |
| #[stable(feature = "pointer_methods", since = "1.26.0")] |
| #[inline] |
| pub unsafe fn write(self, val: T) |
| where |
| T: Sized, |
| { |
| write(self, val) |
| } |
| |
| /// Invokes memset on the specified pointer, setting `count * size_of::<T>()` |
| /// bytes of memory starting at `self` to `val`. |
| /// |
| /// See [`ptr::write_bytes`] for safety concerns and examples. |
| /// |
| /// [`ptr::write_bytes`]: ./ptr/fn.write_bytes.html |
| #[stable(feature = "pointer_methods", since = "1.26.0")] |
| #[inline] |
| pub unsafe fn write_bytes(self, val: u8, count: usize) |
| where |
| T: Sized, |
| { |
| write_bytes(self, val, count) |
| } |
| |
| /// Performs a volatile write of a memory location with the given value without |
| /// reading or dropping the old value. |
| /// |
| /// Volatile operations are intended to act on I/O memory, and are guaranteed |
| /// to not be elided or reordered by the compiler across other volatile |
| /// operations. |
| /// |
| /// See [`ptr::write_volatile`] for safety concerns and examples. |
| /// |
| /// [`ptr::write_volatile`]: ./ptr/fn.write_volatile.html |
| #[stable(feature = "pointer_methods", since = "1.26.0")] |
| #[inline] |
| pub unsafe fn write_volatile(self, val: T) |
| where |
| T: Sized, |
| { |
| write_volatile(self, val) |
| } |
| |
| /// Overwrites a memory location with the given value without reading or |
| /// dropping the old value. |
| /// |
| /// Unlike `write`, the pointer may be unaligned. |
| /// |
| /// See [`ptr::write_unaligned`] for safety concerns and examples. |
| /// |
| /// [`ptr::write_unaligned`]: ./ptr/fn.write_unaligned.html |
| #[stable(feature = "pointer_methods", since = "1.26.0")] |
| #[inline] |
| pub unsafe fn write_unaligned(self, val: T) |
| where |
| T: Sized, |
| { |
| write_unaligned(self, val) |
| } |
| |
| /// Replaces the value at `self` with `src`, returning the old |
| /// value, without dropping either. |
| /// |
| /// See [`ptr::replace`] for safety concerns and examples. |
| /// |
| /// [`ptr::replace`]: ./ptr/fn.replace.html |
| #[stable(feature = "pointer_methods", since = "1.26.0")] |
| #[inline] |
| pub unsafe fn replace(self, src: T) -> T |
| where |
| T: Sized, |
| { |
| replace(self, src) |
| } |
| |
| /// Swaps the values at two mutable locations of the same type, without |
| /// deinitializing either. They may overlap, unlike `mem::swap` which is |
| /// otherwise equivalent. |
| /// |
| /// See [`ptr::swap`] for safety concerns and examples. |
| /// |
| /// [`ptr::swap`]: ./ptr/fn.swap.html |
| #[stable(feature = "pointer_methods", since = "1.26.0")] |
| #[inline] |
| pub unsafe fn swap(self, with: *mut T) |
| where |
| T: Sized, |
| { |
| swap(self, with) |
| } |
| |
| /// Computes the offset that needs to be applied to the pointer in order to make it aligned to |
| /// `align`. |
| /// |
| /// If it is not possible to align the pointer, the implementation returns |
| /// `usize::max_value()`. It is permissible for the implementation to *always* |
| /// return `usize::max_value()`. Only your algorithm's performance can depend |
| /// on getting a usable offset here, not its correctness. |
| /// |
| /// The offset is expressed in number of `T` elements, and not bytes. The value returned can be |
| /// used with the `wrapping_add` method. |
| /// |
| /// There are no guarantees whatsoever that offsetting the pointer will not overflow or go |
| /// beyond the allocation that the pointer points into. It is up to the caller to ensure that |
| /// the returned offset is correct in all terms other than alignment. |
| /// |
| /// # Panics |
| /// |
| /// The function panics if `align` is not a power-of-two. |
| /// |
| /// # Examples |
| /// |
| /// Accessing adjacent `u8` as `u16` |
| /// |
| /// ``` |
| /// # fn foo(n: usize) { |
| /// # use std::mem::align_of; |
| /// # unsafe { |
| /// let x = [5u8, 6u8, 7u8, 8u8, 9u8]; |
| /// let ptr = &x[n] as *const u8; |
| /// let offset = ptr.align_offset(align_of::<u16>()); |
| /// if offset < x.len() - n - 1 { |
| /// let u16_ptr = ptr.add(offset) as *const u16; |
| /// assert_ne!(*u16_ptr, 500); |
| /// } else { |
| /// // while the pointer can be aligned via `offset`, it would point |
| /// // outside the allocation |
| /// } |
| /// # } } |
| /// ``` |
| #[stable(feature = "align_offset", since = "1.36.0")] |
| pub fn align_offset(self, align: usize) -> usize |
| where |
| T: Sized, |
| { |
| if !align.is_power_of_two() { |
| panic!("align_offset: align is not a power-of-two"); |
| } |
| unsafe { align_offset(self, align) } |
| } |
| } |
| |
| // Equality for pointers |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T: ?Sized> PartialEq for *mut T { |
| #[inline] |
| fn eq(&self, other: &*mut T) -> bool { |
| *self == *other |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T: ?Sized> Eq for *mut T {} |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T: ?Sized> Ord for *mut T { |
| #[inline] |
| fn cmp(&self, other: &*mut T) -> Ordering { |
| if self < other { |
| Less |
| } else if self == other { |
| Equal |
| } else { |
| Greater |
| } |
| } |
| } |
| |
| #[stable(feature = "rust1", since = "1.0.0")] |
| impl<T: ?Sized> PartialOrd for *mut T { |
| #[inline] |
| fn partial_cmp(&self, other: &*mut T) -> Option<Ordering> { |
| Some(self.cmp(other)) |
| } |
| |
| #[inline] |
| fn lt(&self, other: &*mut T) -> bool { |
| *self < *other |
| } |
| |
| #[inline] |
| fn le(&self, other: &*mut T) -> bool { |
| *self <= *other |
| } |
| |
| #[inline] |
| fn gt(&self, other: &*mut T) -> bool { |
| *self > *other |
| } |
| |
| #[inline] |
| fn ge(&self, other: &*mut T) -> bool { |
| *self >= *other |
| } |
| } |
