/rust/registry/src/index.crates.io-1949cf8c6b5b557f/integer-encoding-3.0.4/src/fixed.rs

Source
use std::mem::{size_of, transmute};

/// `FixedInt` provides encoding/decoding to and from fixed int representations.
///
/// The emitted bytestring contains the bytes of the integer in machine endianness.
pub trait FixedInt: Sized + Copy {
    const REQUIRED_SPACE: usize;
    /// Returns how many bytes are required to represent the given type.
    fn required_space() -> usize;
    /// Encode a value into the given slice. `dst` must be exactly `REQUIRED_SPACE` bytes.
    fn encode_fixed(self, dst: &mut [u8]);
    /// Decode a value from the given slice. `src` must be exactly `REQUIRED_SPACE` bytes.
    fn decode_fixed(src: &[u8]) -> Self;
    /// Perform a transmute, i.e. return a "view" into the integer's memory, which is faster than
    /// performing a copy.
    fn encode_fixed_light<'a>(&'a self) -> &'a [u8];

    /// Helper: Encode the value and return a Vec.
    fn encode_fixed_vec(self) -> Vec<u8> {
        let mut v = Vec::new();
        v.resize(Self::required_space(), 0);
        self.encode_fixed(&mut v[..]);
        v
    }
    /// Helper: Decode the value from the Vec.
    fn decode_fixed_vec(v: &Vec<u8>) -> Self {
        assert_eq!(v.len(), Self::required_space());
        Self::decode_fixed(&v[..])
    }
}

macro_rules! impl_fixedint {
    ($t:ty) => {
        impl FixedInt for $t {
            const REQUIRED_SPACE: usize = size_of::<Self>();

            fn required_space() -> usize {
                Self::REQUIRED_SPACE
            }

            fn encode_fixed_light<'a>(&'a self) -> &'a [u8] {
                return unsafe {
                    std::slice::from_raw_parts(
                        transmute::<&$t, *const u8>(&self),
                        Self::REQUIRED_SPACE,
                    )
                };
            }

            fn encode_fixed(self, dst: &mut [u8]) {
                assert_eq!(dst.len(), Self::REQUIRED_SPACE);

                #[allow(unused_mut)]
                let mut encoded =
                    unsafe { &*(&self as *const $t as *const [u8; Self::REQUIRED_SPACE]) };

                #[cfg(target_endian = "big")]
                if Self::REQUIRED_SPACE > 1 {
                    let mut encoded_rev = [0 as u8; Self::REQUIRED_SPACE];
                    encoded_rev.copy_from_slice(encoded);
                    encoded_rev.reverse();
                    dst.clone_from_slice(&encoded_rev);
                    return;
                }

                dst.clone_from_slice(encoded);
            }

            #[cfg(target_endian = "little")]
            fn decode_fixed(src: &[u8]) -> $t {
                unsafe { (src.as_ptr() as *const $t).read_unaligned() }
            }

            #[cfg(target_endian = "big")]
            fn decode_fixed(src: &[u8]) -> $t {
                match Self::REQUIRED_SPACE {
                    1 => unsafe { (src.as_ptr() as *const $t).read_unaligned() },
                    _ => {
                        let mut src_fin = [0 as u8; Self::REQUIRED_SPACE];
                        src_fin.copy_from_slice(src);
                        src_fin.reverse();
                        unsafe { (src_fin.as_ptr() as *const $t).read_unaligned() }
                    }
                }
            }
        }
    };
}

impl_fixedint!(usize);
impl_fixedint!(u64);
impl_fixedint!(u32);
impl_fixedint!(u16);
impl_fixedint!(u8);
impl_fixedint!(isize);
impl_fixedint!(i64);
impl_fixedint!(i32);
impl_fixedint!(i16);
impl_fixedint!(i8);

Line	Count	Source
1		use std::mem::{size_of, transmute};
2
3		/// `FixedInt` provides encoding/decoding to and from fixed int representations.
4		///
5		/// The emitted bytestring contains the bytes of the integer in machine endianness.
6		pub trait FixedInt: Sized + Copy {
7		const REQUIRED_SPACE: usize;
8		/// Returns how many bytes are required to represent the given type.
9		fn required_space() -> usize;
10		/// Encode a value into the given slice. `dst` must be exactly `REQUIRED_SPACE` bytes.
11		fn encode_fixed(self, dst: &mut [u8]);
12		/// Decode a value from the given slice. `src` must be exactly `REQUIRED_SPACE` bytes.
13		fn decode_fixed(src: &[u8]) -> Self;
14		/// Perform a transmute, i.e. return a "view" into the integer's memory, which is faster than
15		/// performing a copy.
16		fn encode_fixed_light<'a>(&'a self) -> &'a [u8];
17
18		/// Helper: Encode the value and return a Vec.
19	0	fn encode_fixed_vec(self) -> Vec<u8> {
20	0	let mut v = Vec::new();
21	0	v.resize(Self::required_space(), 0);
22	0	self.encode_fixed(&mut v[..]);
23	0	v
24	0	}
25		/// Helper: Decode the value from the Vec.
26	0	fn decode_fixed_vec(v: &Vec<u8>) -> Self {
27	0	assert_eq!(v.len(), Self::required_space());
28	0	Self::decode_fixed(&v[..])
29	0	}
30		}
31
32		macro_rules! impl_fixedint {
33		($t:ty) => {
34		impl FixedInt for $t {
35		const REQUIRED_SPACE: usize = size_of::<Self>();
36
37	0	fn required_space() -> usize {
38	0	Self::REQUIRED_SPACE
39	0	} Unexecuted instantiation: <usize as integer_encoding::fixed::FixedInt>::required_space Unexecuted instantiation: <u32 as integer_encoding::fixed::FixedInt>::required_space Unexecuted instantiation: <u16 as integer_encoding::fixed::FixedInt>::required_space Unexecuted instantiation: <u8 as integer_encoding::fixed::FixedInt>::required_space Unexecuted instantiation: <isize as integer_encoding::fixed::FixedInt>::required_space Unexecuted instantiation: <i64 as integer_encoding::fixed::FixedInt>::required_space Unexecuted instantiation: <i32 as integer_encoding::fixed::FixedInt>::required_space Unexecuted instantiation: <i16 as integer_encoding::fixed::FixedInt>::required_space Unexecuted instantiation: <i8 as integer_encoding::fixed::FixedInt>::required_space Unexecuted instantiation: <u64 as integer_encoding::fixed::FixedInt>::required_space
40
41	0	fn encode_fixed_light<'a>(&'a self) -> &'a [u8] {
42		return unsafe {
43	0	std::slice::from_raw_parts(
44	0	transmute::<&$t, *const u8>(&self),
45	0	Self::REQUIRED_SPACE,
46	0	)
47		};
48	0	} Unexecuted instantiation: <usize as integer_encoding::fixed::FixedInt>::encode_fixed_light Unexecuted instantiation: <u32 as integer_encoding::fixed::FixedInt>::encode_fixed_light Unexecuted instantiation: <u16 as integer_encoding::fixed::FixedInt>::encode_fixed_light Unexecuted instantiation: <u8 as integer_encoding::fixed::FixedInt>::encode_fixed_light Unexecuted instantiation: <isize as integer_encoding::fixed::FixedInt>::encode_fixed_light Unexecuted instantiation: <i64 as integer_encoding::fixed::FixedInt>::encode_fixed_light Unexecuted instantiation: <i32 as integer_encoding::fixed::FixedInt>::encode_fixed_light Unexecuted instantiation: <i16 as integer_encoding::fixed::FixedInt>::encode_fixed_light Unexecuted instantiation: <i8 as integer_encoding::fixed::FixedInt>::encode_fixed_light Unexecuted instantiation: <u64 as integer_encoding::fixed::FixedInt>::encode_fixed_light
49
50	0	fn encode_fixed(self, dst: &mut [u8]) {
51	0	assert_eq!(dst.len(), Self::REQUIRED_SPACE);
52
53		#[allow(unused_mut)]
54	0	let mut encoded =
55	0	unsafe { &(&self as const $t as *const [u8; Self::REQUIRED_SPACE]) };
56
57		#[cfg(target_endian = "big")]
58		if Self::REQUIRED_SPACE > 1 {
59		let mut encoded_rev = [0 as u8; Self::REQUIRED_SPACE];
60		encoded_rev.copy_from_slice(encoded);
61		encoded_rev.reverse();
62		dst.clone_from_slice(&encoded_rev);
63		return;
64		}
65
66	0	dst.clone_from_slice(encoded);
67	0	} Unexecuted instantiation: <usize as integer_encoding::fixed::FixedInt>::encode_fixed Unexecuted instantiation: <u32 as integer_encoding::fixed::FixedInt>::encode_fixed Unexecuted instantiation: <u16 as integer_encoding::fixed::FixedInt>::encode_fixed Unexecuted instantiation: <u8 as integer_encoding::fixed::FixedInt>::encode_fixed Unexecuted instantiation: <isize as integer_encoding::fixed::FixedInt>::encode_fixed Unexecuted instantiation: <i64 as integer_encoding::fixed::FixedInt>::encode_fixed Unexecuted instantiation: <i32 as integer_encoding::fixed::FixedInt>::encode_fixed Unexecuted instantiation: <i16 as integer_encoding::fixed::FixedInt>::encode_fixed Unexecuted instantiation: <i8 as integer_encoding::fixed::FixedInt>::encode_fixed Unexecuted instantiation: <u64 as integer_encoding::fixed::FixedInt>::encode_fixed
68
69		#[cfg(target_endian = "little")]
70	0	fn decode_fixed(src: &[u8]) -> $t {
71	0	unsafe { (src.as_ptr() as *const $t).read_unaligned() }
72	0	} Unexecuted instantiation: <usize as integer_encoding::fixed::FixedInt>::decode_fixed Unexecuted instantiation: <u32 as integer_encoding::fixed::FixedInt>::decode_fixed Unexecuted instantiation: <u16 as integer_encoding::fixed::FixedInt>::decode_fixed Unexecuted instantiation: <u8 as integer_encoding::fixed::FixedInt>::decode_fixed Unexecuted instantiation: <isize as integer_encoding::fixed::FixedInt>::decode_fixed Unexecuted instantiation: <i64 as integer_encoding::fixed::FixedInt>::decode_fixed Unexecuted instantiation: <i32 as integer_encoding::fixed::FixedInt>::decode_fixed Unexecuted instantiation: <i16 as integer_encoding::fixed::FixedInt>::decode_fixed Unexecuted instantiation: <i8 as integer_encoding::fixed::FixedInt>::decode_fixed Unexecuted instantiation: <u64 as integer_encoding::fixed::FixedInt>::decode_fixed
73
74		#[cfg(target_endian = "big")]
75		fn decode_fixed(src: &[u8]) -> $t {
76		match Self::REQUIRED_SPACE {
77		1 => unsafe { (src.as_ptr() as *const $t).read_unaligned() },
78		_ => {
79		let mut src_fin = [0 as u8; Self::REQUIRED_SPACE];
80		src_fin.copy_from_slice(src);
81		src_fin.reverse();
82		unsafe { (src_fin.as_ptr() as *const $t).read_unaligned() }
83		}
84		}
85		}
86		}
87		};
88		}
89
90		impl_fixedint!(usize);
91		impl_fixedint!(u64);
92		impl_fixedint!(u32);
93		impl_fixedint!(u16);
94		impl_fixedint!(u8);
95		impl_fixedint!(isize);
96		impl_fixedint!(i64);
97		impl_fixedint!(i32);
98		impl_fixedint!(i16);
99		impl_fixedint!(i8);

Coverage Report

Created: 2026-03-08 07:06