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// Copyright 2019 The Fuchsia Authors
//
// Licensed under a BSD-style license <LICENSE-BSD>, Apache License, Version 2.0
// This file may not be copied, modified, or distributed except according to
// those terms.
//! Byte order-aware numeric primitives.
//!
//! This module contains equivalents of the native multi-byte integer types with
//! no alignment requirement and supporting byte order conversions.
//!
//! For each native multi-byte integer type - `u16`, `i16`, `u32`, etc - and
//! floating point type - `f32` and `f64` - an equivalent type is defined by
//! this module - [`U16`], [`I16`], [`U32`], [`F64`], etc. Unlike their native
//! counterparts, these types have alignment 1, and take a type parameter
//! specifying the byte order in which the bytes are stored in memory. Each type
//! implements the [`FromBytes`], [`AsBytes`], and [`Unaligned`] traits.
//!
//! These two properties, taken together, make these types useful for defining
//! data structures whose memory layout matches a wire format such as that of a
//! network protocol or a file format. Such formats often have multi-byte values
//! at offsets that do not respect the alignment requirements of the equivalent
//! native types, and stored in a byte order not necessarily the same as that of
//! the target platform.
//!
//! Type aliases are provided for common byte orders in the [`big_endian`],
//! [`little_endian`], [`network_endian`], and [`native_endian`] submodules.
//!
//! # Example
//!
//! One use of these types is for representing network packet formats, such as
//! UDP:
//!
//! ```rust,edition2021
//! # #[cfg(feature = "derive")] { // This example uses derives, and won't compile without them
//! use zerocopy::{AsBytes, ByteSlice, FromBytes, FromZeroes, Ref, Unaligned};
//! use zerocopy::byteorder::network_endian::U16;
//!
//! #[derive(FromZeroes, FromBytes, AsBytes, Unaligned)]
//! #[repr(C)]
//! struct UdpHeader {
//! src_port: U16,
//! dst_port: U16,
//! length: U16,
//! checksum: U16,
//! }
//!
//! struct UdpPacket<B: ByteSlice> {
//! header: Ref<B, UdpHeader>,
//! body: B,
//! }
//!
//! impl<B: ByteSlice> UdpPacket<B> {
//! fn parse(bytes: B) -> Option<UdpPacket<B>> {
//! let (header, body) = Ref::new_from_prefix(bytes)?;
//! Some(UdpPacket { header, body })
//! }
//!
//! fn src_port(&self) -> u16 {
//! self.header.src_port.get()
//! }
//!
//! // more getters...
//! }
//! # }
//! ```
use core::{
convert::{TryFrom, TryInto},
fmt::{self, Binary, Debug, Display, Formatter, LowerHex, Octal, UpperHex},
marker::PhantomData,
num::TryFromIntError,
};
// We don't reexport `WriteBytesExt` or `ReadBytesExt` because those are only
// available with the `std` feature enabled, and zerocopy is `no_std` by
// default.
pub use ::byteorder::{BigEndian, ByteOrder, LittleEndian, NativeEndian, NetworkEndian, BE, LE};
use super::*;
macro_rules! impl_fmt_trait {
($name:ident, $native:ident, $trait:ident) => {
impl<O: ByteOrder> $trait for $name<O> {
#[inline(always)]
fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
$trait::fmt(&self.get(), f)
}
}
};
}
macro_rules! impl_fmt_traits {
($name:ident, $native:ident, "floating point number") => {
impl_fmt_trait!($name, $native, Display);
};
($name:ident, $native:ident, "unsigned integer") => {
impl_fmt_traits!($name, $native, @all_types);
};
($name:ident, $native:ident, "signed integer") => {
impl_fmt_traits!($name, $native, @all_types);
};
($name:ident, $native:ident, @all_types) => {
impl_fmt_trait!($name, $native, Display);
impl_fmt_trait!($name, $native, Octal);
impl_fmt_trait!($name, $native, LowerHex);
impl_fmt_trait!($name, $native, UpperHex);
impl_fmt_trait!($name, $native, Binary);
};
}
macro_rules! impl_ops_traits {
($name:ident, $native:ident, "floating point number") => {
impl_ops_traits!($name, $native, @all_types);
impl_ops_traits!($name, $native, @signed_integer_floating_point);
};
($name:ident, $native:ident, "unsigned integer") => {
impl_ops_traits!($name, $native, @signed_unsigned_integer);
impl_ops_traits!($name, $native, @all_types);
};
($name:ident, $native:ident, "signed integer") => {
impl_ops_traits!($name, $native, @signed_unsigned_integer);
impl_ops_traits!($name, $native, @signed_integer_floating_point);
impl_ops_traits!($name, $native, @all_types);
};
($name:ident, $native:ident, @signed_unsigned_integer) => {
impl_ops_traits!(@without_byteorder_swap $name, $native, BitAnd, bitand, BitAndAssign, bitand_assign);
impl_ops_traits!(@without_byteorder_swap $name, $native, BitOr, bitor, BitOrAssign, bitor_assign);
impl_ops_traits!(@without_byteorder_swap $name, $native, BitXor, bitxor, BitXorAssign, bitxor_assign);
impl_ops_traits!(@with_byteorder_swap $name, $native, Shl, shl, ShlAssign, shl_assign);
impl_ops_traits!(@with_byteorder_swap $name, $native, Shr, shr, ShrAssign, shr_assign);
impl<O> core::ops::Not for $name<O> {
type Output = $name<O>;
#[inline(always)]
fn not(self) -> $name<O> {
let self_native = $native::from_ne_bytes(self.0);
$name((!self_native).to_ne_bytes(), PhantomData)
}
}
};
($name:ident, $native:ident, @signed_integer_floating_point) => {
impl<O: ByteOrder> core::ops::Neg for $name<O> {
type Output = $name<O>;
#[inline(always)]
fn neg(self) -> $name<O> {
let self_native: $native = self.get();
#[allow(clippy::arithmetic_side_effects)]
$name::<O>::new(-self_native)
}
}
};
($name:ident, $native:ident, @all_types) => {
impl_ops_traits!(@with_byteorder_swap $name, $native, Add, add, AddAssign, add_assign);
impl_ops_traits!(@with_byteorder_swap $name, $native, Div, div, DivAssign, div_assign);
impl_ops_traits!(@with_byteorder_swap $name, $native, Mul, mul, MulAssign, mul_assign);
impl_ops_traits!(@with_byteorder_swap $name, $native, Rem, rem, RemAssign, rem_assign);
impl_ops_traits!(@with_byteorder_swap $name, $native, Sub, sub, SubAssign, sub_assign);
};
(@with_byteorder_swap $name:ident, $native:ident, $trait:ident, $method:ident, $trait_assign:ident, $method_assign:ident) => {
impl<O: ByteOrder> core::ops::$trait for $name<O> {
type Output = $name<O>;
#[inline(always)]
fn $method(self, rhs: $name<O>) -> $name<O> {
let self_native: $native = self.get();
let rhs_native: $native = rhs.get();
let result_native = core::ops::$trait::$method(self_native, rhs_native);
$name::<O>::new(result_native)
}
}
impl<O: ByteOrder> core::ops::$trait_assign for $name<O> {
#[inline(always)]
fn $method_assign(&mut self, rhs: $name<O>) {
*self = core::ops::$trait::$method(*self, rhs);
}
}
};
// Implement traits in terms of the same trait on the native type, but
// without performing a byte order swap. This only works for bitwise
// operations like `&`, `|`, etc.
(@without_byteorder_swap $name:ident, $native:ident, $trait:ident, $method:ident, $trait_assign:ident, $method_assign:ident) => {
impl<O: ByteOrder> core::ops::$trait for $name<O> {
type Output = $name<O>;
#[inline(always)]
fn $method(self, rhs: $name<O>) -> $name<O> {
let self_native = $native::from_ne_bytes(self.0);
let rhs_native = $native::from_ne_bytes(rhs.0);
let result_native = core::ops::$trait::$method(self_native, rhs_native);
$name(result_native.to_ne_bytes(), PhantomData)
}
}
impl<O: ByteOrder> core::ops::$trait_assign for $name<O> {
#[inline(always)]
fn $method_assign(&mut self, rhs: $name<O>) {
*self = core::ops::$trait::$method(*self, rhs);
}
}
};
}
macro_rules! doc_comment {
($x:expr, $($tt:tt)*) => {
#[doc = $x]
$($tt)*
};
}
macro_rules! define_max_value_constant {
($name:ident, $bytes:expr, "unsigned integer") => {
/// The maximum value.
///
/// This constant should be preferred to constructing a new value using
/// `new`, as `new` may perform an endianness swap depending on the
/// endianness `O` and the endianness of the platform.
pub const MAX_VALUE: $name<O> = $name([0xFFu8; $bytes], PhantomData);
};
// We don't provide maximum and minimum value constants for signed values
// and floats because there's no way to do it generically - it would require
// a different value depending on the value of the `ByteOrder` type
// parameter. Currently, one workaround would be to provide implementations
// for concrete implementations of that trait. In the long term, if we are
// ever able to make the `new` constructor a const fn, we could use that
// instead.
($name:ident, $bytes:expr, "signed integer") => {};
($name:ident, $bytes:expr, "floating point number") => {};
}
macro_rules! define_type {
($article:ident,
$name:ident,
$native:ident,
$bits:expr,
$bytes:expr,
$read_method:ident,
$write_method:ident,
$number_kind:tt,
[$($larger_native:ty),*],
[$($larger_native_try:ty),*],
[$($larger_byteorder:ident),*],
[$($larger_byteorder_try:ident),*]) => {
doc_comment! {
concat!("A ", stringify!($bits), "-bit ", $number_kind,
" stored in a given byte order.
`", stringify!($name), "` is like the native `", stringify!($native), "` type with
two major differences: First, it has no alignment requirement (its alignment is 1).
Second, the endianness of its memory layout is given by the type parameter `O`,
which can be any type which implements [`ByteOrder`]. In particular, this refers
to [`BigEndian`], [`LittleEndian`], [`NativeEndian`], and [`NetworkEndian`].
", stringify!($article), " `", stringify!($name), "` can be constructed using
the [`new`] method, and its contained value can be obtained as a native
`",stringify!($native), "` using the [`get`] method, or updated in place with
the [`set`] method. In all cases, if the endianness `O` is not the same as the
endianness of the current platform, an endianness swap will be performed in
order to uphold the invariants that a) the layout of `", stringify!($name), "`
has endianness `O` and that, b) the layout of `", stringify!($native), "` has
the platform's native endianness.
`", stringify!($name), "` implements [`FromBytes`], [`AsBytes`], and [`Unaligned`],
making it useful for parsing and serialization. See the module documentation for an
example of how it can be used for parsing UDP packets.
[`new`]: crate::byteorder::", stringify!($name), "::new
[`get`]: crate::byteorder::", stringify!($name), "::get
[`set`]: crate::byteorder::", stringify!($name), "::set
[`FromBytes`]: crate::FromBytes
[`AsBytes`]: crate::AsBytes
[`Unaligned`]: crate::Unaligned"),
#[derive(Copy, Clone, Eq, PartialEq, Hash)]
#[cfg_attr(any(feature = "derive", test), derive(KnownLayout, FromZeroes, FromBytes, AsBytes, Unaligned))]
#[repr(transparent)]
pub struct $name<O>([u8; $bytes], PhantomData<O>);
}
#[cfg(not(any(feature = "derive", test)))]
impl_known_layout!(O => $name<O>);
safety_comment! {
/// SAFETY:
/// `$name<O>` is `repr(transparent)`, and so it has the same layout
/// as its only non-zero field, which is a `u8` array. `u8` arrays
/// are `FromZeroes`, `FromBytes`, `AsBytes`, and `Unaligned`.
impl_or_verify!(O => FromZeroes for $name<O>);
impl_or_verify!(O => FromBytes for $name<O>);
impl_or_verify!(O => AsBytes for $name<O>);
impl_or_verify!(O => Unaligned for $name<O>);
}
impl<O> Default for $name<O> {
#[inline(always)]
fn default() -> $name<O> {
$name::ZERO
}
}
impl<O> $name<O> {
/// The value zero.
///
/// This constant should be preferred to constructing a new value
/// using `new`, as `new` may perform an endianness swap depending
/// on the endianness and platform.
pub const ZERO: $name<O> = $name([0u8; $bytes], PhantomData);
define_max_value_constant!($name, $bytes, $number_kind);
/// Constructs a new value from bytes which are already in the
/// endianness `O`.
#[inline(always)]
pub const fn from_bytes(bytes: [u8; $bytes]) -> $name<O> {
$name(bytes, PhantomData)
}
}
impl<O: ByteOrder> $name<O> {
// TODO(joshlf): Make these const fns if the `ByteOrder` methods
// ever become const fns.
/// Constructs a new value, possibly performing an endianness swap
/// to guarantee that the returned value has endianness `O`.
#[inline(always)]
pub fn new(n: $native) -> $name<O> {
let mut out = $name::default();
O::$write_method(&mut out.0[..], n);
out
}
/// Returns the value as a primitive type, possibly performing an
/// endianness swap to guarantee that the return value has the
/// endianness of the native platform.
#[inline(always)]
pub fn get(self) -> $native {
O::$read_method(&self.0[..])
}
/// Updates the value in place as a primitive type, possibly
/// performing an endianness swap to guarantee that the stored value
/// has the endianness `O`.
#[inline(always)]
pub fn set(&mut self, n: $native) {
O::$write_method(&mut self.0[..], n);
}
}
// The reasoning behind which traits to implement here is to only
// implement traits which won't cause inference issues. Notably,
// comparison traits like PartialEq and PartialOrd tend to cause
// inference issues.
impl<O: ByteOrder> From<$name<O>> for [u8; $bytes] {
#[inline(always)]
fn from(x: $name<O>) -> [u8; $bytes] {
x.0
}
}
impl<O: ByteOrder> From<[u8; $bytes]> for $name<O> {
#[inline(always)]
fn from(bytes: [u8; $bytes]) -> $name<O> {
$name(bytes, PhantomData)
}
}
impl<O: ByteOrder> From<$name<O>> for $native {
#[inline(always)]
fn from(x: $name<O>) -> $native {
x.get()
}
}
impl<O: ByteOrder> From<$native> for $name<O> {
#[inline(always)]
fn from(x: $native) -> $name<O> {
$name::new(x)
}
}
$(
impl<O: ByteOrder> From<$name<O>> for $larger_native {
#[inline(always)]
fn from(x: $name<O>) -> $larger_native {
x.get().into()
}
}
)*
$(
impl<O: ByteOrder> TryFrom<$larger_native_try> for $name<O> {
type Error = TryFromIntError;
#[inline(always)]
fn try_from(x: $larger_native_try) -> Result<$name<O>, TryFromIntError> {
$native::try_from(x).map($name::new)
}
}
)*
$(
impl<O: ByteOrder, P: ByteOrder> From<$name<O>> for $larger_byteorder<P> {
#[inline(always)]
fn from(x: $name<O>) -> $larger_byteorder<P> {
$larger_byteorder::new(x.get().into())
}
}
)*
$(
impl<O: ByteOrder, P: ByteOrder> TryFrom<$larger_byteorder_try<P>> for $name<O> {
type Error = TryFromIntError;
#[inline(always)]
fn try_from(x: $larger_byteorder_try<P>) -> Result<$name<O>, TryFromIntError> {
x.get().try_into().map($name::new)
}
}
)*
impl<O: ByteOrder> AsRef<[u8; $bytes]> for $name<O> {
#[inline(always)]
fn as_ref(&self) -> &[u8; $bytes] {
&self.0
}
}
impl<O: ByteOrder> AsMut<[u8; $bytes]> for $name<O> {
#[inline(always)]
fn as_mut(&mut self) -> &mut [u8; $bytes] {
&mut self.0
}
}
impl<O: ByteOrder> PartialEq<$name<O>> for [u8; $bytes] {
#[inline(always)]
fn eq(&self, other: &$name<O>) -> bool {
self.eq(&other.0)
}
}
impl<O: ByteOrder> PartialEq<[u8; $bytes]> for $name<O> {
#[inline(always)]
fn eq(&self, other: &[u8; $bytes]) -> bool {
self.0.eq(other)
}
}
impl_fmt_traits!($name, $native, $number_kind);
impl_ops_traits!($name, $native, $number_kind);
impl<O: ByteOrder> Debug for $name<O> {
#[inline]
fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
// This results in a format like "U16(42)".
f.debug_tuple(stringify!($name)).field(&self.get()).finish()
}
}
};
}
define_type!(
A,
U16,
u16,
16,
2,
read_u16,
write_u16,
"unsigned integer",
[u32, u64, u128, usize],
[u32, u64, u128, usize],
[U32, U64, U128],
[U32, U64, U128]
);
define_type!(
A,
U32,
u32,
32,
4,
read_u32,
write_u32,
"unsigned integer",
[u64, u128],
[u64, u128],
[U64, U128],
[U64, U128]
);
define_type!(
A,
U64,
u64,
64,
8,
read_u64,
write_u64,
"unsigned integer",
[u128],
[u128],
[U128],
[U128]
);
define_type!(A, U128, u128, 128, 16, read_u128, write_u128, "unsigned integer", [], [], [], []);
define_type!(
An,
I16,
i16,
16,
2,
read_i16,
write_i16,
"signed integer",
[i32, i64, i128, isize],
[i32, i64, i128, isize],
[I32, I64, I128],
[I32, I64, I128]
);
define_type!(
An,
I32,
i32,
32,
4,
read_i32,
write_i32,
"signed integer",
[i64, i128],
[i64, i128],
[I64, I128],
[I64, I128]
);
define_type!(
An,
I64,
i64,
64,
8,
read_i64,
write_i64,
"signed integer",
[i128],
[i128],
[I128],
[I128]
);
define_type!(An, I128, i128, 128, 16, read_i128, write_i128, "signed integer", [], [], [], []);
define_type!(
An,
F32,
f32,
32,
4,
read_f32,
write_f32,
"floating point number",
[f64],
[],
[F64],
[]
);
define_type!(An, F64, f64, 64, 8, read_f64, write_f64, "floating point number", [], [], [], []);
macro_rules! module {
($name:ident, $trait:ident, $endianness_str:expr) => {
/// Numeric primitives stored in
#[doc = $endianness_str]
/// byte order.
pub mod $name {
use byteorder::$trait;
module!(@ty U16, $trait, "16-bit unsigned integer", $endianness_str);
module!(@ty U32, $trait, "32-bit unsigned integer", $endianness_str);
module!(@ty U64, $trait, "64-bit unsigned integer", $endianness_str);
module!(@ty U128, $trait, "128-bit unsigned integer", $endianness_str);
module!(@ty I16, $trait, "16-bit signed integer", $endianness_str);
module!(@ty I32, $trait, "32-bit signed integer", $endianness_str);
module!(@ty I64, $trait, "64-bit signed integer", $endianness_str);
module!(@ty I128, $trait, "128-bit signed integer", $endianness_str);
module!(@ty F32, $trait, "32-bit floating point number", $endianness_str);
module!(@ty F64, $trait, "64-bit floating point number", $endianness_str);
}
};
(@ty $ty:ident, $trait:ident, $desc_str:expr, $endianness_str:expr) => {
/// A
#[doc = $desc_str]
/// stored in
#[doc = $endianness_str]
/// byte order.
pub type $ty = crate::byteorder::$ty<$trait>;
};
}
module!(big_endian, BigEndian, "big-endian");
module!(little_endian, LittleEndian, "little-endian");
module!(network_endian, NetworkEndian, "network-endian");
module!(native_endian, NativeEndian, "native-endian");
#[cfg(any(test, kani))]
mod tests {
use ::byteorder::NativeEndian;
use {
super::*,
crate::{AsBytes, FromBytes, Unaligned},
};
#[cfg(not(kani))]
mod compatibility {
pub(super) use rand::{
distributions::{Distribution, Standard},
rngs::SmallRng,
Rng, SeedableRng,
};
pub(crate) trait Arbitrary {}
impl<T> Arbitrary for T {}
}
#[cfg(kani)]
mod compatibility {
pub(crate) use kani::Arbitrary;
pub(crate) struct SmallRng;
impl SmallRng {
pub(crate) fn seed_from_u64(_state: u64) -> Self {
Self
}
}
pub(crate) trait Rng {
fn sample<T, D: Distribution<T>>(&mut self, _distr: D) -> T
where
T: Arbitrary,
{
kani::any()
}
}
impl Rng for SmallRng {}
pub(crate) trait Distribution<T> {}
impl<T, U> Distribution<T> for U {}
pub(crate) struct Standard;
}
use compatibility::*;
// A native integer type (u16, i32, etc).
trait Native: Arbitrary + FromBytes + AsBytes + Copy + PartialEq + Debug {
const ZERO: Self;
const MAX_VALUE: Self;
type Distribution: Distribution<Self>;
const DIST: Self::Distribution;
fn rand<R: Rng>(rng: &mut R) -> Self {
rng.sample(Self::DIST)
}
#[cfg(kani)]
fn any() -> Self {
kani::any()
}
fn checked_add(self, rhs: Self) -> Option<Self>;
fn checked_div(self, rhs: Self) -> Option<Self>;
fn checked_mul(self, rhs: Self) -> Option<Self>;
fn checked_rem(self, rhs: Self) -> Option<Self>;
fn checked_sub(self, rhs: Self) -> Option<Self>;
fn checked_shl(self, rhs: Self) -> Option<Self>;
fn checked_shr(self, rhs: Self) -> Option<Self>;
fn is_nan(self) -> bool;
/// For `f32` and `f64`, NaN values are not considered equal to
/// themselves. This method is like `assert_eq!`, but it treats NaN
/// values as equal.
fn assert_eq_or_nan(self, other: Self) {
let slf = (!self.is_nan()).then(|| self);
let other = (!other.is_nan()).then(|| other);
assert_eq!(slf, other);
}
}
trait ByteArray:
FromBytes + AsBytes + Copy + AsRef<[u8]> + AsMut<[u8]> + Debug + Default + Eq
{
/// Invert the order of the bytes in the array.
fn invert(self) -> Self;
}
trait ByteOrderType: FromBytes + AsBytes + Unaligned + Copy + Eq + Debug {
type Native: Native;
type ByteArray: ByteArray;
const ZERO: Self;
fn new(native: Self::Native) -> Self;
fn get(self) -> Self::Native;
fn set(&mut self, native: Self::Native);
fn from_bytes(bytes: Self::ByteArray) -> Self;
fn into_bytes(self) -> Self::ByteArray;
/// For `f32` and `f64`, NaN values are not considered equal to
/// themselves. This method is like `assert_eq!`, but it treats NaN
/// values as equal.
fn assert_eq_or_nan(self, other: Self) {
let slf = (!self.get().is_nan()).then(|| self);
let other = (!other.get().is_nan()).then(|| other);
assert_eq!(slf, other);
}
}
trait ByteOrderTypeUnsigned: ByteOrderType {
const MAX_VALUE: Self;
}
macro_rules! impl_byte_array {
($bytes:expr) => {
impl ByteArray for [u8; $bytes] {
fn invert(mut self) -> [u8; $bytes] {
self.reverse();
self
}
}
};
}
impl_byte_array!(2);
impl_byte_array!(4);
impl_byte_array!(8);
impl_byte_array!(16);
macro_rules! impl_byte_order_type_unsigned {
($name:ident, unsigned) => {
impl<O: ByteOrder> ByteOrderTypeUnsigned for $name<O> {
const MAX_VALUE: $name<O> = $name::MAX_VALUE;
}
};
($name:ident, signed) => {};
}
macro_rules! impl_traits {
($name:ident, $native:ident, $bytes:expr, $sign:ident $(, @$float:ident)?) => {
impl Native for $native {
// For some types, `0 as $native` is required (for example, when
// `$native` is a floating-point type; `0` is an integer), but
// for other types, it's a trivial cast. In all cases, Clippy
// thinks it's dangerous.
#[allow(trivial_numeric_casts, clippy::as_conversions)]
const ZERO: $native = 0 as $native;
const MAX_VALUE: $native = $native::MAX;
type Distribution = Standard;
const DIST: Standard = Standard;
impl_traits!(@float_dependent_methods $(@$float)?);
}
impl<O: ByteOrder> ByteOrderType for $name<O> {
type Native = $native;
type ByteArray = [u8; $bytes];
const ZERO: $name<O> = $name::ZERO;
fn new(native: $native) -> $name<O> {
$name::new(native)
}
fn get(self) -> $native {
$name::get(self)
}
fn set(&mut self, native: $native) {
$name::set(self, native)
}
fn from_bytes(bytes: [u8; $bytes]) -> $name<O> {
$name::from(bytes)
}
fn into_bytes(self) -> [u8; $bytes] {
<[u8; $bytes]>::from(self)
}
}
impl_byte_order_type_unsigned!($name, $sign);
};
(@float_dependent_methods) => {
fn checked_add(self, rhs: Self) -> Option<Self> { self.checked_add(rhs) }
fn checked_div(self, rhs: Self) -> Option<Self> { self.checked_div(rhs) }
fn checked_mul(self, rhs: Self) -> Option<Self> { self.checked_mul(rhs) }
fn checked_rem(self, rhs: Self) -> Option<Self> { self.checked_rem(rhs) }
fn checked_sub(self, rhs: Self) -> Option<Self> { self.checked_sub(rhs) }
fn checked_shl(self, rhs: Self) -> Option<Self> { self.checked_shl(rhs.try_into().unwrap_or(u32::MAX)) }
fn checked_shr(self, rhs: Self) -> Option<Self> { self.checked_shr(rhs.try_into().unwrap_or(u32::MAX)) }
fn is_nan(self) -> bool { false }
};
(@float_dependent_methods @float) => {
fn checked_add(self, rhs: Self) -> Option<Self> { Some(self + rhs) }
fn checked_div(self, rhs: Self) -> Option<Self> { Some(self / rhs) }
fn checked_mul(self, rhs: Self) -> Option<Self> { Some(self * rhs) }
fn checked_rem(self, rhs: Self) -> Option<Self> { Some(self % rhs) }
fn checked_sub(self, rhs: Self) -> Option<Self> { Some(self - rhs) }
fn checked_shl(self, _rhs: Self) -> Option<Self> { unimplemented!() }
fn checked_shr(self, _rhs: Self) -> Option<Self> { unimplemented!() }
fn is_nan(self) -> bool { self.is_nan() }
};
}
impl_traits!(U16, u16, 2, unsigned);
impl_traits!(U32, u32, 4, unsigned);
impl_traits!(U64, u64, 8, unsigned);
impl_traits!(U128, u128, 16, unsigned);
impl_traits!(I16, i16, 2, signed);
impl_traits!(I32, i32, 4, signed);
impl_traits!(I64, i64, 8, signed);
impl_traits!(I128, i128, 16, signed);
impl_traits!(F32, f32, 4, signed, @float);
impl_traits!(F64, f64, 8, signed, @float);
macro_rules! call_for_unsigned_types {
($fn:ident, $byteorder:ident) => {
$fn::<U16<$byteorder>>();
$fn::<U32<$byteorder>>();
$fn::<U64<$byteorder>>();
$fn::<U128<$byteorder>>();
};
}
macro_rules! call_for_signed_types {
($fn:ident, $byteorder:ident) => {
$fn::<I16<$byteorder>>();
$fn::<I32<$byteorder>>();
$fn::<I64<$byteorder>>();
$fn::<I128<$byteorder>>();
};
}
macro_rules! call_for_float_types {
($fn:ident, $byteorder:ident) => {
$fn::<F32<$byteorder>>();
$fn::<F64<$byteorder>>();
};
}
macro_rules! call_for_all_types {
($fn:ident, $byteorder:ident) => {
call_for_unsigned_types!($fn, $byteorder);
call_for_signed_types!($fn, $byteorder);
call_for_float_types!($fn, $byteorder);
};
}
#[cfg(target_endian = "big")]
type NonNativeEndian = LittleEndian;
#[cfg(target_endian = "little")]
type NonNativeEndian = BigEndian;
// We use a `u64` seed so that we can use `SeedableRng::seed_from_u64`.
// `SmallRng`'s `SeedableRng::Seed` differs by platform, so if we wanted to
// call `SeedableRng::from_seed`, which takes a `Seed`, we would need
// conditional compilation by `target_pointer_width`.
const RNG_SEED: u64 = 0x7A03CAE2F32B5B8F;
const RAND_ITERS: usize = if cfg!(any(miri, kani)) {
// The tests below which use this constant used to take a very long time
// on Miri, which slows down local development and CI jobs. We're not
// using Miri to check for the correctness of our code, but rather its
// soundness, and at least in the context of these particular tests, a
// single loop iteration is just as good for surfacing UB as multiple
// iterations are.
//
// As of the writing of this comment, here's one set of measurements:
//
// $ # RAND_ITERS == 1
// $ cargo miri test -- -Z unstable-options --report-time endian
// test byteorder::tests::test_native_endian ... ok <0.049s>
// test byteorder::tests::test_non_native_endian ... ok <0.061s>
//
// $ # RAND_ITERS == 1024
// $ cargo miri test -- -Z unstable-options --report-time endian
// test byteorder::tests::test_native_endian ... ok <25.716s>
// test byteorder::tests::test_non_native_endian ... ok <38.127s>
1
} else {
1024
};
#[cfg_attr(test, test)]
#[cfg_attr(kani, kani::proof)]
fn test_zero() {
fn test_zero<T: ByteOrderType>() {
assert_eq!(T::ZERO.get(), T::Native::ZERO);
}
call_for_all_types!(test_zero, NativeEndian);
call_for_all_types!(test_zero, NonNativeEndian);
}
#[cfg_attr(test, test)]
#[cfg_attr(kani, kani::proof)]
fn test_max_value() {
fn test_max_value<T: ByteOrderTypeUnsigned>() {
assert_eq!(T::MAX_VALUE.get(), T::Native::MAX_VALUE);
}
call_for_unsigned_types!(test_max_value, NativeEndian);
call_for_unsigned_types!(test_max_value, NonNativeEndian);
}
#[cfg_attr(test, test)]
#[cfg_attr(kani, kani::proof)]
fn test_endian() {
fn test<T: ByteOrderType>(invert: bool) {
let mut r = SmallRng::seed_from_u64(RNG_SEED);
for _ in 0..RAND_ITERS {
let native = T::Native::rand(&mut r);
let mut bytes = T::ByteArray::default();
bytes.as_bytes_mut().copy_from_slice(native.as_bytes());
if invert {
bytes = bytes.invert();
}
let mut from_native = T::new(native);
let from_bytes = T::from_bytes(bytes);
from_native.assert_eq_or_nan(from_bytes);
from_native.get().assert_eq_or_nan(native);
from_bytes.get().assert_eq_or_nan(native);
assert_eq!(from_native.into_bytes(), bytes);
assert_eq!(from_bytes.into_bytes(), bytes);
let updated = T::Native::rand(&mut r);
from_native.set(updated);
from_native.get().assert_eq_or_nan(updated);
}
}
fn test_native<T: ByteOrderType>() {
test::<T>(false);
}
fn test_non_native<T: ByteOrderType>() {
test::<T>(true);
}
call_for_all_types!(test_native, NativeEndian);
call_for_all_types!(test_non_native, NonNativeEndian);
}
#[test]
fn test_ops_impls() {
// Test implementations of traits in `core::ops`. Some of these are
// fairly banal, but some are optimized to perform the operation without
// swapping byte order (namely, bit-wise operations which are identical
// regardless of byte order). These are important to test, and while
// we're testing those anyway, it's trivial to test all of the impls.
fn test<T, F, G, H>(op: F, op_native: G, op_native_checked: Option<H>)
where
T: ByteOrderType,
F: Fn(T, T) -> T,
G: Fn(T::Native, T::Native) -> T::Native,
H: Fn(T::Native, T::Native) -> Option<T::Native>,
{
let mut r = SmallRng::seed_from_u64(RNG_SEED);
for _ in 0..RAND_ITERS {
let n0 = T::Native::rand(&mut r);
let n1 = T::Native::rand(&mut r);
let t0 = T::new(n0);
let t1 = T::new(n1);
// If this operation would overflow/underflow, skip it rather
// than attempt to catch and recover from panics.
if matches!(&op_native_checked, Some(checked) if checked(n0, n1).is_none()) {
continue;
}
let n_res = op_native(n0, n1);
let t_res = op(t0, t1);
// For `f32` and `f64`, NaN values are not considered equal to
// themselves. We store `Option<f32>`/`Option<f64>` and store
// NaN as `None` so they can still be compared.
let n_res = (!T::Native::is_nan(n_res)).then(|| n_res);
let t_res = (!T::Native::is_nan(t_res.get())).then(|| t_res.get());
assert_eq!(n_res, t_res);
}
}
macro_rules! test {
(@binary $trait:ident, $method:ident $([$checked_method:ident])?, $($call_for_macros:ident),*) => {{
test!(
@inner $trait,
core::ops::$trait::$method,
core::ops::$trait::$method,
{
#[allow(unused_mut, unused_assignments)]
let mut op_native_checked = None::<fn(T::Native, T::Native) -> Option<T::Native>>;
$(
op_native_checked = Some(T::Native::$checked_method);
)?
op_native_checked
},
$($call_for_macros),*
);
}};
(@unary $trait:ident, $method:ident $([$checked_method:ident])?, $($call_for_macros:ident),*) => {{
test!(
@inner $trait,
|slf, _rhs| core::ops::$trait::$method(slf),
|slf, _rhs| core::ops::$trait::$method(slf),
{
#[allow(unused_mut, unused_assignments)]
let mut op_native_checked = None::<fn(T::Native, T::Native) -> Option<T::Native>>;
$(
op_native_checked = Some(|slf, _rhs| T::Native::$checked_method(slf));
)?
op_native_checked
},
$($call_for_macros),*
);
}};
(@inner $trait:ident, $op:expr, $op_native:expr, $op_native_checked:expr, $($call_for_macros:ident),*) => {{
fn t<T: ByteOrderType + core::ops::$trait<Output = T>>()
where
T::Native: core::ops::$trait<Output = T::Native>,
{
test::<T, _, _, _>(
$op,
$op_native,
$op_native_checked,
);
}
$(
$call_for_macros!(t, NativeEndian);
$call_for_macros!(t, NonNativeEndian);
)*
}};
}
test!(@binary Add, add[checked_add], call_for_all_types);
test!(@binary Div, div[checked_div], call_for_all_types);
test!(@binary Mul, mul[checked_mul], call_for_all_types);
test!(@binary Rem, rem[checked_rem], call_for_all_types);
test!(@binary Sub, sub[checked_sub], call_for_all_types);
test!(@binary BitAnd, bitand, call_for_unsigned_types, call_for_signed_types);
test!(@binary BitOr, bitor, call_for_unsigned_types, call_for_signed_types);
test!(@binary BitXor, bitxor, call_for_unsigned_types, call_for_signed_types);
test!(@binary Shl, shl[checked_shl], call_for_unsigned_types, call_for_signed_types);
test!(@binary Shr, shr[checked_shr], call_for_unsigned_types, call_for_signed_types);
test!(@unary Not, not, call_for_signed_types, call_for_unsigned_types);
test!(@unary Neg, neg, call_for_signed_types, call_for_float_types);
}
#[test]
fn test_debug_impl() {
// Ensure that Debug applies format options to the inner value.
let val = U16::<LE>::new(10);
assert_eq!(format!("{:?}", val), "U16(10)");
assert_eq!(format!("{:03?}", val), "U16(010)");
assert_eq!(format!("{:x?}", val), "U16(a)");
}
}