1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
use core::fmt;
use core::mem::{ManuallyDrop, MaybeUninit};

pub(crate) mod alloc;

pub(crate) mod utils;

#[cfg(feature = "zeroize")]
pub(crate) mod zero;

pub use self::alloc::{
    FixedAlloc, Global, RawAlloc, RawAllocIn, RawAllocNew, SpillAlloc, SpillStorage, Thin,
};

#[cfg(feature = "zeroize")]
pub use self::zero::ZeroizingAlloc;

pub trait RawBuffer: Sized {
    type RawData: ?Sized;

    fn data_ptr(&self) -> *const Self::RawData;

    fn data_ptr_mut(&mut self) -> *mut Self::RawData;
}

pub trait WithAlloc<'a>: Sized {
    type NewIn<A: 'a>;

    #[inline]
    fn with_alloc(self) -> Self::NewIn<Global> {
        Self::with_alloc_in(self, Global)
    }

    fn with_alloc_in<A: RawAlloc + 'a>(self, alloc: A) -> Self::NewIn<A>;
}

#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
pub struct ArrayStorage<A>(pub A);

impl<A> ArrayStorage<A> {
    pub const fn new(inner: A) -> Self {
        Self(inner)
    }
}

impl<T, const N: usize> ArrayStorage<[MaybeUninit<T>; N]> {
    pub fn as_uninit_slice(&mut self) -> &mut [MaybeUninit<T>] {
        &mut self.0
    }
}

#[repr(C)]
pub union ByteStorage<T, const N: usize> {
    _align: [ManuallyDrop<T>; 0],
    data: [MaybeUninit<u8>; N],
}

impl<T, const N: usize> ByteStorage<T, N> {
    pub const fn new() -> Self {
        Self {
            data: unsafe { MaybeUninit::uninit().assume_init() },
        }
    }

    pub fn as_uninit_slice(&mut self) -> &mut [MaybeUninit<u8>] {
        unsafe { &mut self.data }
    }
}

impl<'a, T: 'static, const N: usize> WithAlloc<'a> for &'a mut ByteStorage<T, N> {
    type NewIn<A: 'a> = SpillStorage<'a, Self, A>;

    #[inline]
    fn with_alloc_in<A: RawAlloc + 'a>(self, alloc: A) -> Self::NewIn<A> {
        SpillStorage::new_in(self, alloc)
    }
}

impl<T, const N: usize> fmt::Debug for ByteStorage<T, N> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_struct("ByteStorage").finish_non_exhaustive()
    }
}

pub const fn array_storage<T, const N: usize>() -> ArrayStorage<[MaybeUninit<T>; N]> {
    ArrayStorage::new(unsafe { MaybeUninit::uninit().assume_init() })
}

pub const fn byte_storage<const N: usize>() -> ByteStorage<u8, N> {
    ByteStorage::<u8, N>::new()
}

pub const fn aligned_byte_storage<T, const N: usize>() -> ByteStorage<T, N> {
    ByteStorage::<T, N>::new()
}

#[derive(Debug, Default, Copy, Clone, PartialEq, Eq, PartialOrd, Ord)]
pub struct Inline<const N: usize>;

#[derive(Debug)]
pub struct InlineBuffer<T, const N: usize> {
    pub data: [MaybeUninit<T>; N],
    pub length: usize,
}

impl<T, const N: usize> InlineBuffer<T, N> {
    pub const fn new() -> Self {
        Self {
            data: unsafe { MaybeUninit::uninit().assume_init() },
            length: 0,
        }
    }
}

impl<T, const N: usize> Default for InlineBuffer<T, N> {
    fn default() -> Self {
        Self::new()
    }
}

impl<'a, T: 'a, const N: usize> RawBuffer for InlineBuffer<T, N> {
    type RawData = T;

    #[inline]
    fn data_ptr(&self) -> *const T {
        self.data.as_ptr().cast()
    }

    #[inline]
    fn data_ptr_mut(&mut self) -> *mut T {
        self.data.as_mut_ptr().cast()
    }
}