vendor/tinyvec/src/array.rs

   1 /// A trait for types that are an array.
   2 ///
   3 /// An "array", for our purposes, has the following properties:
   4 /// * Owns some number of elements.
   5 /// * The element type can be generic, but must implement [`Default`].
   6 /// * The capacity is fixed at compile time, based on the implementing type.
   7 /// * You can get a shared or mutable slice to the elements.
   8 ///
   9 /// You are generally **not** expected to need to implement this yourself. It is
  10 /// already implemented for all the major array lengths (`0..=32` and the powers
  11 /// of 2 up to 4,096).
  12 ///
  13 /// **Additional lengths can easily be added upon request.**
  14 ///
  15 /// ## Safety Reminder
  16 ///
  17 /// Just a reminder: this trait is 100% safe, which means that `unsafe` code
  18 /// **must not** rely on an instance of this trait being correct.
  19 pub trait Array {
  20   /// The type of the items in the thing.
  21   type Item: Default;
  22
  23   /// The number of slots in the thing.
  24   const CAPACITY: usize;
  25
  26   /// Gives a shared slice over the whole thing.
  27   ///
  28   /// A correct implementation will return a slice with a length equal to the
  29   /// `CAPACITY` value.
  30   fn as_slice(&self) -> &[Self::Item];
  31
  32   /// Gives a unique slice over the whole thing.
  33   ///
  34   /// A correct implementation will return a slice with a length equal to the
  35   /// `CAPACITY` value.
  36   fn as_slice_mut(&mut self) -> &mut [Self::Item];
  37
  38   /// Create a default-initialized instance of ourself, similar to the
  39   /// [`Default`] trait, but implemented for the same range of sizes as
  40   /// [`Array`].
  41   fn default() -> Self;
  42 }
  43
  44 #[cfg(feature = "nightly_const_generics")]
  45 mod const_generic_impl;
  46
  47 #[cfg(not(feature = "nightly_const_generics"))]
  48 mod generated_impl;