le-stream 8.0.0

De-/serialize objects from/to little endian byte streams
Documentation 
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

use core::iter::once;
use core::marker::PhantomData;
use core::ops::{Range, RangeInclusive};

use crate::FromLeStream;

macro_rules! impl_primitives {
    ($($typ:ty,)+) => {
        $(
            impl FromLeStream for $typ {
                fn from_le_stream<T>(bytes: T) -> Option<Self>
                where
                    T: Iterator<Item = u8>,
                {
                    <[u8; size_of::<Self>()]>::from_le_stream(bytes).map(Self::from_le_bytes)
                }
            }
        )+
    };
}

// Implement u8 separately, since all other conversions depend on it.
impl_primitives!(
    u16, u32, u64, u128, usize, i8, i16, i32, i64, i128, isize, f32, f64,
);

impl FromLeStream for u8 {
    fn from_le_stream<T>(mut bytes: T) -> Option<Self>
    where
        T: Iterator<Item = Self>,
    {
        bytes.next()
    }
}

impl FromLeStream for () {
    /// This is guaranteed to always return `Some(())`.
    fn from_le_stream<T>(_: T) -> Option<Self>
    where
        T: Iterator<Item = u8>,
    {
        Some(())
    }
}

impl<T> FromLeStream for PhantomData<T> {
    /// This is guaranteed to always return `Some(PhantomData<T>)`.
    fn from_le_stream<I>(_: I) -> Option<Self>
    where
        I: Iterator<Item = u8>,
    {
        Some(Self)
    }
}

impl FromLeStream for bool {
    fn from_le_stream<T>(mut bytes: T) -> Option<Self>
    where
        T: Iterator<Item = u8>,
    {
        bytes.next().map(|byte| byte != 0)
    }
}

impl<T, const SIZE: usize> FromLeStream for [T; SIZE]
where
    T: FromLeStream,
{
    fn from_le_stream<I>(mut bytes: I) -> Option<Self>
    where
        I: Iterator<Item = u8>,
    {
        let mut array = [const { None }; SIZE];

        for element in &mut array {
            element.replace(T::from_le_stream(&mut bytes)?);
        }

        Some(array.map(|element| element.expect("All elements are initialized.")))
    }
}

impl<T> FromLeStream for Option<T>
where
    T: FromLeStream,
{
    /// This is guaranteed to always return `Some(Option<T>)`.
    fn from_le_stream<I>(mut bytes: I) -> Option<Self>
    where
        I: Iterator<Item = u8>,
    {
        bytes.next().map_or_else(
            || Some(None),
            |byte| T::from_le_stream(once(byte).chain(bytes)).map(Some),
        )
    }
}

impl<T> FromLeStream for Range<T>
where
    T: FromLeStream,
{
    fn from_le_stream<I>(mut bytes: I) -> Option<Self>
    where
        I: Iterator<Item = u8>,
    {
        let start = T::from_le_stream(&mut bytes)?;
        let end = T::from_le_stream(&mut bytes)?;
        Some(start..end)
    }
}

impl<T> FromLeStream for RangeInclusive<T>
where
    T: FromLeStream,
{
    fn from_le_stream<I>(mut bytes: I) -> Option<Self>
    where
        I: Iterator<Item = u8>,
    {
        let start = T::from_le_stream(&mut bytes)?;
        let end = T::from_le_stream(&mut bytes)?;
        Some(start..=end)
    }
}