byte/ctx/
num.rs

1#![allow(unused_parens)]
2
3use crate::{check_len, Error, Result, TryRead, TryWrite};
4use core::convert::TryInto;
5use core::mem;
6
7/// Endiannes of numbers.
8///
9/// Defaults to the machine's endianness.
10///
11/// # Example
12///
13/// ```
14/// use byte::*;
15///
16/// let bytes: &[u8] = &[0x00, 0xff];
17///
18/// let num_be: u16 = bytes.read_with(&mut 0, BE).unwrap();
19/// assert_eq!(num_be, 0x00ff);
20///
21/// let num_le: u16 = bytes.read_with(&mut 0, LE).unwrap();
22/// assert_eq!(num_le, 0xff00);
23/// ```
24#[derive(Debug, PartialEq, Eq, Copy, Clone)]
25pub enum Endian {
26    /// Little Endian byte order context
27    Little,
28    /// Big Endian byte order context
29    Big,
30}
31
32impl Default for Endian {
33    #[inline]
34    fn default() -> Self {
35        NATIVE
36    }
37}
38
39/// Little endian byte order
40pub const LE: Endian = Endian::Little;
41/// Big endian byte order
42pub const BE: Endian = Endian::Big;
43
44/// Network endian
45pub const NETWORK: Endian = Endian::Little;
46
47/// The machine's native endianness
48#[cfg(target_endian = "little")]
49pub const NATIVE: Endian = LE;
50/// The machine's native endiannes
51#[cfg(target_endian = "big")]
52pub const NATIVE: Endian = BE;
53
54macro_rules! num_impl {
55    ($ty: ty, $size: tt) => {
56        impl<'a> TryRead<'a, Endian> for $ty {
57            #[inline]
58            fn try_read(bytes: &'a [u8], endian: Endian) -> Result<(Self, usize)> {
59                check_len(bytes, $size)?;
60
61                let val = match endian {
62                    Endian::Big => {
63                        <$ty>::from_be_bytes(bytes[..$size].try_into().map_err(|_e| {
64                            Error::BadInput {
65                                err: "TryIntoSliceError",
66                            }
67                        })?)
68                    }
69                    Endian::Little => {
70                        <$ty>::from_le_bytes(bytes[..$size].try_into().map_err(|_e| {
71                            Error::BadInput {
72                                err: "TryIntoSliceError",
73                            }
74                        })?)
75                    }
76                };
77
78                Ok((val, $size))
79            }
80        }
81
82        impl TryWrite<Endian> for $ty {
83            #[inline]
84            fn try_write(self, bytes: &mut [u8], endian: Endian) -> Result<usize> {
85                check_len(bytes, $size)?;
86
87                let _val = match endian {
88                    Endian::Big => bytes[..$size].copy_from_slice(&self.to_be_bytes()),
89                    Endian::Little => bytes[..$size].copy_from_slice(&self.to_le_bytes()),
90                };
91
92                Ok($size)
93            }
94        }
95    };
96}
97
98num_impl!(u8, 1);
99num_impl!(u16, 2);
100num_impl!(u32, 4);
101num_impl!(u64, 8);
102num_impl!(i8, 1);
103num_impl!(i16, 2);
104num_impl!(i32, 4);
105num_impl!(i64, 8);
106num_impl!(usize, (mem::size_of::<usize>()));
107num_impl!(isize, (mem::size_of::<isize>()));
108
109macro_rules! float_impl {
110    ($ty: ty, $base: ty) => {
111        impl<'a> TryRead<'a, Endian> for $ty {
112            #[inline]
113            fn try_read(bytes: &'a [u8], endian: Endian) -> Result<(Self, usize)> {
114                <$base as TryRead<'a, Endian>>::try_read(bytes, endian)
115                    .map(|(val, size)| (<$ty>::from_bits(val), size))
116            }
117        }
118
119        impl<'a> TryWrite<Endian> for $ty {
120            #[inline]
121            fn try_write(self, bytes: &mut [u8], endian: Endian) -> Result<usize> {
122                <$base as TryWrite<Endian>>::try_write(self.to_bits(), bytes, endian)
123            }
124        }
125    };
126}
127
128float_impl!(f32, u32);
129float_impl!(f64, u64);
byte/ctx/num.rs

byte/ctx/
num.rs
