src/vendor/arrayvec/src/array.rs

   1
   2 /// Trait for fixed size arrays.
   3 pub unsafe trait Array {
   4     /// The array’s element type
   5     type Item;
   6     #[doc(hidden)]
   7     /// The smallest index type that indexes the array.
   8     type Index: Index;
   9     #[doc(hidden)]
  10     fn as_ptr(&self) -> *const Self::Item;
  11     #[doc(hidden)]
  12     fn as_mut_ptr(&mut self) -> *mut Self::Item;
  13     #[doc(hidden)]
  14     fn capacity() -> usize;
  15 }
  16
  17 pub trait Index : PartialEq + Copy {
  18     fn to_usize(self) -> usize;
  19     fn from(usize) -> Self;
  20 }
  21
  22 use std::slice::{from_raw_parts};
  23
  24 pub trait ArrayExt : Array {
  25     #[inline(always)]
  26     fn as_slice(&self) -> &[Self::Item] {
  27         unsafe {
  28             from_raw_parts(self.as_ptr(), Self::capacity())
  29         }
  30     }
  31 }
  32
  33 impl<A> ArrayExt for A where A: Array { }
  34
  35 impl Index for u8 {
  36     #[inline(always)]
  37     fn to_usize(self) -> usize { self as usize }
  38     #[inline(always)]
  39     fn from(ix: usize) ->  Self { ix as u8 }
  40 }
  41
  42 impl Index for u16 {
  43     #[inline(always)]
  44     fn to_usize(self) -> usize { self as usize }
  45     #[inline(always)]
  46     fn from(ix: usize) ->  Self { ix as u16 }
  47 }
  48
  49 impl Index for u32 {
  50     #[inline(always)]
  51     fn to_usize(self) -> usize { self as usize }
  52     #[inline(always)]
  53     fn from(ix: usize) ->  Self { ix as u32 }
  54 }
  55
  56 impl Index for usize {
  57     #[inline(always)]
  58     fn to_usize(self) -> usize { self }
  59     #[inline(always)]
  60     fn from(ix: usize) ->  Self { ix }
  61 }
  62
  63 macro_rules! fix_array_impl {
  64     ($index_type:ty, $len:expr ) => (
  65         unsafe impl<T> Array for [T; $len] {
  66             type Item = T;
  67             type Index = $index_type;
  68             #[inline(always)]
  69             fn as_ptr(&self) -> *const T { self as *const _ as *const _ }
  70             #[inline(always)]
  71             fn as_mut_ptr(&mut self) -> *mut T { self as *mut _ as *mut _}
  72             #[inline(always)]
  73             fn capacity() -> usize { $len }
  74         }
  75     )
  76 }
  77
  78 macro_rules! fix_array_impl_recursive {
  79     ($index_type:ty, ) => ();
  80     ($index_type:ty, $len:expr, $($more:expr,)*) => (
  81         fix_array_impl!($index_type, $len);
  82         fix_array_impl_recursive!($index_type, $($more,)*);
  83     );
  84 }
  85
  86 fix_array_impl_recursive!(u8, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
  87                           16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
  88                           32, 40, 48, 50, 56, 64, 72, 96, 100, 128, 160, 192, 200, 224,);
  89 fix_array_impl_recursive!(u16, 256, 384, 512, 768, 1024, 2048, 4096, 8192, 16384, 32768,);
  90 // This array size doesn't exist on 16-bit
  91 #[cfg(any(target_pointer_width="32", target_pointer_width="64"))]
  92 fix_array_impl_recursive!(u32, 1 << 16,);
  93