// Copyright 2019 The Fuchsia Authors // // Licensed under a BSD-style license , Apache License, Version 2.0 // , or the MIT // license , at your option. // 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`], [`F32`], [`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 this crate's relevant conversion and marker 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 //! use zerocopy::{*, byteorder::network_endian::U16}; //! # use zerocopy_derive::*; //! //! #[derive(FromBytes, IntoBytes, KnownLayout, Immutable, Unaligned)] //! #[repr(C)] //! struct UdpHeader { //! src_port: U16, //! dst_port: U16, //! length: U16, //! checksum: U16, //! } //! //! #[derive(FromBytes, IntoBytes, KnownLayout, Immutable, Unaligned)] //! #[repr(C, packed)] //! struct UdpPacket { //! header: UdpHeader, //! body: [u8], //! } //! //! impl UdpPacket { //! fn parse(bytes: &[u8]) -> Option<&UdpPacket> { //! UdpPacket::ref_from_bytes(bytes).ok() //! } //! } //! ``` use core::{ convert::{TryFrom, TryInto}, fmt::{Binary, Debug, LowerHex, Octal, UpperHex}, hash::Hash, num::TryFromIntError, }; use super::*; /// A type-level representation of byte order. /// /// This type is implemented by [`BigEndian`] and [`LittleEndian`], which /// represent big-endian and little-endian byte order respectively. This module /// also provides a number of useful aliases for those types: [`NativeEndian`], /// [`NetworkEndian`], [`BE`], and [`LE`]. /// /// `ByteOrder` types can be used to specify the byte order of the types in this /// module - for example, [`U32`] is a 32-bit integer stored in /// big-endian byte order. /// /// [`U32`]: U32 pub trait ByteOrder: Copy + Clone + Debug + Display + Eq + PartialEq + Ord + PartialOrd + Hash + private::Sealed { #[doc(hidden)] const ORDER: Order; } mod private { pub trait Sealed {} impl Sealed for super::BigEndian {} impl Sealed for super::LittleEndian {} } #[allow(missing_copy_implementations, missing_debug_implementations)] #[doc(hidden)] pub enum Order { BigEndian, LittleEndian, } /// Big-endian byte order. /// /// See [`ByteOrder`] for more details. #[derive(Copy, Clone, Debug, Eq, PartialEq, Ord, PartialOrd, Hash)] pub enum BigEndian {} impl ByteOrder for BigEndian { const ORDER: Order = Order::BigEndian; } impl Display for BigEndian { #[inline] fn fmt(&self, _: &mut Formatter<'_>) -> fmt::Result { match *self {} } } /// Little-endian byte order. /// /// See [`ByteOrder`] for more details. #[derive(Copy, Clone, Debug, Eq, PartialEq, Ord, PartialOrd, Hash)] pub enum LittleEndian {} impl ByteOrder for LittleEndian { const ORDER: Order = Order::LittleEndian; } impl Display for LittleEndian { #[inline] fn fmt(&self, _: &mut Formatter<'_>) -> fmt::Result { match *self {} } } /// The endianness used by this platform. /// /// This is a type alias for [`BigEndian`] or [`LittleEndian`] depending on the /// endianness of the target platform. #[cfg(target_endian = "big")] pub type NativeEndian = BigEndian; /// The endianness used by this platform. /// /// This is a type alias for [`BigEndian`] or [`LittleEndian`] depending on the /// endianness of the target platform. #[cfg(target_endian = "little")] pub type NativeEndian = LittleEndian; /// The endianness used in many network protocols. /// /// This is a type alias for [`BigEndian`]. pub type NetworkEndian = BigEndian; /// A type alias for [`BigEndian`]. pub type BE = BigEndian; /// A type alias for [`LittleEndian`]. pub type LE = LittleEndian; macro_rules! impl_fmt_trait { ($name:ident, $native:ident, $trait:ident) => { impl $trait for $name { #[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); impl PartialOrd for $name { #[inline(always)] fn partial_cmp(&self, other: &Self) -> Option { self.get().partial_cmp(&other.get()) } } }; ($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 core::ops::Not for $name { type Output = $name; #[inline(always)] fn not(self) -> $name { let self_native = $native::from_ne_bytes(self.0); $name((!self_native).to_ne_bytes(), PhantomData) } } impl PartialOrd for $name { #[inline(always)] fn partial_cmp(&self, other: &Self) -> Option { Some(self.cmp(other)) } } impl Ord for $name { #[inline(always)] fn cmp(&self, other: &Self) -> Ordering { self.get().cmp(&other.get()) } } impl PartialOrd<$native> for $name { #[inline(always)] fn partial_cmp(&self, other: &$native) -> Option { self.get().partial_cmp(other) } } }; ($name:ident, $native:ident, @signed_integer_floating_point) => { impl core::ops::Neg for $name { type Output = $name; #[inline(always)] fn neg(self) -> $name { let self_native: $native = self.get(); #[allow(clippy::arithmetic_side_effects)] $name::::new(-self_native) } } }; ($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, $method_assign:ident) => { impl core::ops::$trait<$name> for $name { type Output = $name; #[inline(always)] fn $method(self, rhs: $name) -> $name { let self_native: $native = self.get(); let rhs_native: $native = rhs.get(); let result_native = core::ops::$trait::$method(self_native, rhs_native); $name::::new(result_native) } } impl core::ops::$trait<$name> for $native { type Output = $name; #[inline(always)] fn $method(self, rhs: $name) -> $name { let rhs_native: $native = rhs.get(); let result_native = core::ops::$trait::$method(self, rhs_native); $name::::new(result_native) } } impl core::ops::$trait<$native> for $name { type Output = $name; #[inline(always)] fn $method(self, rhs: $native) -> $name { let self_native: $native = self.get(); let result_native = core::ops::$trait::$method(self_native, rhs); $name::::new(result_native) } } impl core::ops::$trait_assign<$name> for $name { #[inline(always)] fn $method_assign(&mut self, rhs: $name) { *self = core::ops::$trait::$method(*self, rhs); } } impl core::ops::$trait_assign<$name> for $native { #[inline(always)] fn $method_assign(&mut self, rhs: $name) { let rhs_native: $native = rhs.get(); *self = core::ops::$trait::$method(*self, rhs_native); } } impl core::ops::$trait_assign<$native> for $name { #[inline(always)] fn $method_assign(&mut self, rhs: $native) { *self = core::ops::$trait::$method(*self, rhs); } } }; // Implement traits in terms of the same trait on the native type, but // without performing a byte order swap when both operands are byteorder // types. This only works for bitwise operations like `&`, `|`, etc. // // When only one operand is a byteorder type, we still need to perform a // byteorder swap. (@without_byteorder_swap $name:ident, $native:ident, $trait:ident, $method:ident, $trait_assign:ident, $method_assign:ident) => { impl core::ops::$trait<$name> for $name { type Output = $name; #[inline(always)] fn $method(self, rhs: $name) -> $name { 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); $name(result_native.to_ne_bytes(), PhantomData) } } impl core::ops::$trait<$name> for $native { type Output = $name; #[inline(always)] fn $method(self, rhs: $name) -> $name { // No runtime cost - just byte packing let rhs_native = $native::from_ne_bytes(rhs.0); // (Maybe) runtime cost - byte order swap let slf_byteorder = $name::::new(self); // No runtime cost - just byte packing let slf_native = $native::from_ne_bytes(slf_byteorder.0); // Runtime cost - perform the operation let result_native = core::ops::$trait::$method(slf_native, rhs_native); // No runtime cost - just byte unpacking $name(result_native.to_ne_bytes(), PhantomData) } } impl core::ops::$trait<$native> for $name { type Output = $name; #[inline(always)] fn $method(self, rhs: $native) -> $name { // (Maybe) runtime cost - byte order swap let rhs_byteorder = $name::::new(rhs); // No runtime cost - just byte packing let rhs_native = $native::from_ne_bytes(rhs_byteorder.0); // No runtime cost - just byte packing let slf_native = $native::from_ne_bytes(self.0); // Runtime cost - perform the operation let result_native = core::ops::$trait::$method(slf_native, rhs_native); // No runtime cost - just byte unpacking $name(result_native.to_ne_bytes(), PhantomData) } } impl core::ops::$trait_assign<$name> for $name { #[inline(always)] fn $method_assign(&mut self, rhs: $name) { *self = core::ops::$trait::$method(*self, rhs); } } impl core::ops::$trait_assign<$name> for $native { #[inline(always)] fn $method_assign(&mut self, rhs: $name) { // (Maybe) runtime cost - byte order swap let rhs_native = rhs.get(); // Runtime cost - perform the operation *self = core::ops::$trait::$method(*self, rhs_native); } } impl core::ops::$trait_assign<$native> for $name { #[inline(always)] fn $method_assign(&mut self, rhs: $native) { *self = core::ops::$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 = $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, $description:expr, $name:ident, $native:ident, $bits:expr, $bytes:expr, $from_be_fn:path, $to_be_fn:path, $from_le_fn:path, $to_le_fn:path, $number_kind:tt, [$($larger_native:ty),*], [$($larger_native_try:ty),*], [$($larger_byteorder:ident),*], [$($larger_byteorder_try:ident),*] ) => { doc_comment! { concat!($description, " 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`], [`IntoBytes`], 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 [`IntoBytes`]: crate::IntoBytes [`Unaligned`]: crate::Unaligned"), #[derive(Copy, Clone, Eq, PartialEq, Hash)] #[cfg_attr(any(feature = "derive", test), derive(KnownLayout, Immutable, FromBytes, IntoBytes, Unaligned))] #[repr(transparent)] pub struct $name([u8; $bytes], PhantomData); } #[cfg(not(any(feature = "derive", test)))] impl_known_layout!(O => $name); #[allow(unused_unsafe)] // Unused when `feature = "derive"`. // SAFETY: `$name` is `repr(transparent)`, and so it has the same // layout as its only non-zero field, which is a `u8` array. `u8` arrays // are `Immutable`, `TryFromBytes`, `FromZeros`, `FromBytes`, // `IntoBytes`, and `Unaligned`. const _: () = unsafe { impl_or_verify!(O => Immutable for $name); impl_or_verify!(O => TryFromBytes for $name); impl_or_verify!(O => FromZeros for $name); impl_or_verify!(O => FromBytes for $name); impl_or_verify!(O => IntoBytes for $name); impl_or_verify!(O => Unaligned for $name); }; impl Default for $name { #[inline(always)] fn default() -> $name { $name::ZERO } } impl $name { /// 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 = $name([0u8; $bytes], PhantomData); define_max_value_constant!($name, $bytes, $number_kind); /// Constructs a new value from bytes which are already in `O` byte /// order. #[must_use = "has no side effects"] #[inline(always)] pub const fn from_bytes(bytes: [u8; $bytes]) -> $name { $name(bytes, PhantomData) } /// Extracts the bytes of `self` without swapping the byte order. /// /// The returned bytes will be in `O` byte order. #[must_use = "has no side effects"] #[inline(always)] pub const fn to_bytes(self) -> [u8; $bytes] { self.0 } } impl $name { maybe_const_trait_bounded_fn! { /// Constructs a new value, possibly performing an endianness /// swap to guarantee that the returned value has endianness /// `O`. #[must_use = "has no side effects"] #[inline(always)] pub const fn new(n: $native) -> $name { let bytes = match O::ORDER { Order::BigEndian => $to_be_fn(n), Order::LittleEndian => $to_le_fn(n), }; $name(bytes, PhantomData) } } maybe_const_trait_bounded_fn! { /// 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. #[must_use = "has no side effects"] #[inline(always)] pub const fn get(self) -> $native { match O::ORDER { Order::BigEndian => $from_be_fn(self.0), Order::LittleEndian => $from_le_fn(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: $native) { *self = Self::new(n); } } // The reasoning behind which traits to implement here is to only // implement traits which won't cause inference issues. Notably, // comparison traits like PartialEq and PartialOrd tend to cause // inference issues. impl From<$name> for [u8; $bytes] { #[inline(always)] fn from(x: $name) -> [u8; $bytes] { x.0 } } impl From<[u8; $bytes]> for $name { #[inline(always)] fn from(bytes: [u8; $bytes]) -> $name { $name(bytes, PhantomData) } } impl From<$name> for $native { #[inline(always)] fn from(x: $name) -> $native { x.get() } } impl From<$native> for $name { #[inline(always)] fn from(x: $native) -> $name { $name::new(x) } } $( impl From<$name> for $larger_native { #[inline(always)] fn from(x: $name) -> $larger_native { x.get().into() } } )* $( impl TryFrom<$larger_native_try> for $name { type Error = TryFromIntError; #[inline(always)] fn try_from(x: $larger_native_try) -> Result<$name, TryFromIntError> { $native::try_from(x).map($name::new) } } )* $( impl From<$name> for $larger_byteorder

{ #[inline(always)] fn from(x: $name) -> $larger_byteorder

{ $larger_byteorder::new(x.get().into()) } } )* $( impl TryFrom<$larger_byteorder_try

> for $name { type Error = TryFromIntError; #[inline(always)] fn try_from(x: $larger_byteorder_try

) -> Result<$name, TryFromIntError> { x.get().try_into().map($name::new) } } )* impl AsRef<[u8; $bytes]> for $name { #[inline(always)] fn as_ref(&self) -> &[u8; $bytes] { &self.0 } } impl AsMut<[u8; $bytes]> for $name { #[inline(always)] fn as_mut(&mut self) -> &mut [u8; $bytes] { &mut self.0 } } impl PartialEq<$name> for [u8; $bytes] { #[inline(always)] fn eq(&self, other: &$name) -> bool { self.eq(&other.0) } } impl PartialEq<[u8; $bytes]> for $name { #[inline(always)] fn eq(&self, other: &[u8; $bytes]) -> bool { self.0.eq(other) } } impl PartialEq<$native> for $name { #[inline(always)] fn eq(&self, other: &$native) -> bool { self.get().eq(other) } } impl_fmt_traits!($name, $native, $number_kind); impl_ops_traits!($name, $native, $number_kind); impl Debug for $name { #[inline] fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result { // This results in a format like "U16(42)". f.debug_tuple(stringify!($name)).field(&self.get()).finish() } } }; } define_type!( A, "A 16-bit unsigned integer", U16, u16, 16, 2, u16::from_be_bytes, u16::to_be_bytes, u16::from_le_bytes, u16::to_le_bytes, "unsigned integer", [u32, u64, u128, usize], [u32, u64, u128, usize], [U32, U64, U128, Usize], [U32, U64, U128, Usize] ); define_type!( A, "A 32-bit unsigned integer", U32, u32, 32, 4, u32::from_be_bytes, u32::to_be_bytes, u32::from_le_bytes, u32::to_le_bytes, "unsigned integer", [u64, u128], [u64, u128], [U64, U128], [U64, U128] ); define_type!( A, "A 64-bit unsigned integer", U64, u64, 64, 8, u64::from_be_bytes, u64::to_be_bytes, u64::from_le_bytes, u64::to_le_bytes, "unsigned integer", [u128], [u128], [U128], [U128] ); define_type!( A, "A 128-bit unsigned integer", U128, u128, 128, 16, u128::from_be_bytes, u128::to_be_bytes, u128::from_le_bytes, u128::to_le_bytes, "unsigned integer", [], [], [], [] ); define_type!( A, "A word-sized unsigned integer", Usize, usize, mem::size_of::() * 8, mem::size_of::(), usize::from_be_bytes, usize::to_be_bytes, usize::from_le_bytes, usize::to_le_bytes, "unsigned integer", [], [], [], [] ); define_type!( An, "A 16-bit signed integer", I16, i16, 16, 2, i16::from_be_bytes, i16::to_be_bytes, i16::from_le_bytes, i16::to_le_bytes, "signed integer", [i32, i64, i128, isize], [i32, i64, i128, isize], [I32, I64, I128, Isize], [I32, I64, I128, Isize] ); define_type!( An, "A 32-bit signed integer", I32, i32, 32, 4, i32::from_be_bytes, i32::to_be_bytes, i32::from_le_bytes, i32::to_le_bytes, "signed integer", [i64, i128], [i64, i128], [I64, I128], [I64, I128] ); define_type!( An, "A 64-bit signed integer", I64, i64, 64, 8, i64::from_be_bytes, i64::to_be_bytes, i64::from_le_bytes, i64::to_le_bytes, "signed integer", [i128], [i128], [I128], [I128] ); define_type!( An, "A 128-bit signed integer", I128, i128, 128, 16, i128::from_be_bytes, i128::to_be_bytes, i128::from_le_bytes, i128::to_le_bytes, "signed integer", [], [], [], [] ); define_type!( An, "A word-sized signed integer", Isize, isize, mem::size_of::() * 8, mem::size_of::(), isize::from_be_bytes, isize::to_be_bytes, isize::from_le_bytes, isize::to_le_bytes, "signed integer", [], [], [], [] ); // FIXME(https://github.com/rust-lang/rust/issues/72447): Use the endianness // conversion methods directly once those are const-stable. macro_rules! define_float_conversion { ($ty:ty, $bits:ident, $bytes:expr, $mod:ident) => { mod $mod { use super::*; define_float_conversion!($ty, $bits, $bytes, from_be_bytes, to_be_bytes); define_float_conversion!($ty, $bits, $bytes, from_le_bytes, to_le_bytes); } }; ($ty:ty, $bits:ident, $bytes:expr, $from:ident, $to:ident) => { // Clippy: The suggestion of using `from_bits()` instead doesn't work // because `from_bits` is not const-stable on our MSRV. #[allow(clippy::unnecessary_transmutes)] pub(crate) const fn $from(bytes: [u8; $bytes]) -> $ty { transmute!($bits::$from(bytes)) } pub(crate) const fn $to(f: $ty) -> [u8; $bytes] { // Clippy: The suggestion of using `f.to_bits()` instead doesn't // work because `to_bits` is not const-stable on our MSRV. #[allow(clippy::unnecessary_transmutes)] let bits: $bits = transmute!(f); bits.$to() } }; } define_float_conversion!(f32, u32, 4, f32_ext); define_float_conversion!(f64, u64, 8, f64_ext); define_type!( An, "A 32-bit floating point number", F32, f32, 32, 4, f32_ext::from_be_bytes, f32_ext::to_be_bytes, f32_ext::from_le_bytes, f32_ext::to_le_bytes, "floating point number", [f64], [], [F64], [] ); define_type!( An, "A 64-bit floating point number", F64, f64, 64, 8, f64_ext::from_be_bytes, f64_ext::to_be_bytes, f64_ext::from_le_bytes, f64_ext::to_le_bytes, "floating point number", [], [], [], [] ); macro_rules! module { ($name:ident, $trait:ident, $endianness_str:expr) => { /// Numeric primitives stored in #[doc = $endianness_str] /// byte order. pub mod $name { use super::$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 super::*; #[cfg(not(kani))] mod compatibility { pub(super) use rand::{ distributions::{Distribution, Standard}, rngs::SmallRng, Rng, SeedableRng, }; pub(crate) trait Arbitrary {} impl 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>(&mut self, _distr: D) -> T where T: Arbitrary, { kani::any() } } impl Rng for SmallRng {} pub(crate) trait Distribution {} impl Distribution for U {} pub(crate) struct Standard; } use compatibility::*; // A native integer type (u16, i32, etc). trait Native: Arbitrary + FromBytes + IntoBytes + Immutable + Copy + PartialEq + Debug { const ZERO: Self; const MAX_VALUE: Self; type Distribution: Distribution; const DIST: Self::Distribution; fn rand(rng: &mut R) -> Self { rng.sample(Self::DIST) } #[cfg_attr(kani, allow(unused))] fn checked_add(self, rhs: Self) -> Option; #[cfg_attr(kani, allow(unused))] fn checked_div(self, rhs: Self) -> Option; #[cfg_attr(kani, allow(unused))] fn checked_mul(self, rhs: Self) -> Option; #[cfg_attr(kani, allow(unused))] fn checked_rem(self, rhs: Self) -> Option; #[cfg_attr(kani, allow(unused))] fn checked_sub(self, rhs: Self) -> Option; #[cfg_attr(kani, allow(unused))] fn checked_shl(self, rhs: Self) -> Option; #[cfg_attr(kani, allow(unused))] fn checked_shr(self, rhs: Self) -> Option; 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 + IntoBytes + Immutable + Copy + AsRef<[u8]> + AsMut<[u8]> + Debug + Default + Eq { /// Invert the order of the bytes in the array. fn invert(self) -> Self; } trait ByteOrderType: FromBytes + IntoBytes + Unaligned + Copy + Eq + Debug + Hash + From { 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 ByteOrderTypeUnsigned for $name { const MAX_VALUE: $name = $name::MAX_VALUE; } }; ($name:ident, signed) => {}; } macro_rules! impl_traits { ($name:ident, $native:ident, $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 ByteOrderType for $name { type Native = $native; type ByteArray = [u8; mem::size_of::<$native>()]; const ZERO: $name = $name::ZERO; fn new(native: $native) -> $name { $name::new(native) } fn get(self) -> $native { $name::get(self) } fn set(&mut self, native: $native) { $name::set(self, native) } fn from_bytes(bytes: [u8; mem::size_of::<$native>()]) -> $name { $name::from(bytes) } fn into_bytes(self) -> [u8; mem::size_of::<$native>()] { <[u8; mem::size_of::<$native>()]>::from(self) } } impl_byte_order_type_unsigned!($name, $sign); }; (@float_dependent_methods) => { fn checked_add(self, rhs: Self) -> Option { self.checked_add(rhs) } fn checked_div(self, rhs: Self) -> Option { self.checked_div(rhs) } fn checked_mul(self, rhs: Self) -> Option { self.checked_mul(rhs) } fn checked_rem(self, rhs: Self) -> Option { self.checked_rem(rhs) } fn checked_sub(self, rhs: Self) -> Option { self.checked_sub(rhs) } fn checked_shl(self, rhs: Self) -> Option { self.checked_shl(rhs.try_into().unwrap_or(u32::MAX)) } fn checked_shr(self, rhs: Self) -> Option { self.checked_shr(rhs.try_into().unwrap_or(u32::MAX)) } fn is_nan(self) -> bool { false } }; (@float_dependent_methods @float) => { fn checked_add(self, rhs: Self) -> Option { Some(self + rhs) } fn checked_div(self, rhs: Self) -> Option { Some(self / rhs) } fn checked_mul(self, rhs: Self) -> Option { Some(self * rhs) } fn checked_rem(self, rhs: Self) -> Option { Some(self % rhs) } fn checked_sub(self, rhs: Self) -> Option { Some(self - rhs) } fn checked_shl(self, _rhs: Self) -> Option { unimplemented!() } fn checked_shr(self, _rhs: Self) -> Option { unimplemented!() } fn is_nan(self) -> bool { self.is_nan() } }; } impl_traits!(U16, u16, unsigned); impl_traits!(U32, u32, unsigned); impl_traits!(U64, u64, unsigned); impl_traits!(U128, u128, unsigned); impl_traits!(Usize, usize, unsigned); impl_traits!(I16, i16, signed); impl_traits!(I32, i32, signed); impl_traits!(I64, i64, signed); impl_traits!(I128, i128, signed); impl_traits!(Isize, isize, unsigned); impl_traits!(F32, f32, signed, @float); impl_traits!(F64, f64, signed, @float); macro_rules! call_for_unsigned_types { ($fn:ident, $byteorder:ident) => { $fn::>(); $fn::>(); $fn::>(); $fn::>(); $fn::>(); }; } macro_rules! call_for_signed_types { ($fn:ident, $byteorder:ident) => { $fn::>(); $fn::>(); $fn::>(); $fn::>(); $fn::>(); }; } macro_rules! call_for_float_types { ($fn:ident, $byteorder:ident) => { $fn::>(); $fn::>(); }; } macro_rules! call_for_all_types { ($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 }; #[test] fn test_const_methods() { use big_endian::*; #[rustversion::since(1.61.0)] const _U: U16 = U16::new(0); #[rustversion::since(1.61.0)] const _NATIVE: u16 = _U.get(); const _FROM_BYTES: U16 = U16::from_bytes([0, 1]); const _BYTES: [u8; 2] = _FROM_BYTES.to_bytes(); } #[cfg_attr(test, test)] #[cfg_attr(kani, kani::proof)] fn test_zero() { fn test_zero() { 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() { 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(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_mut_bytes().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() { test::(false); } fn test_non_native() { test::(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( op_t_t: FTT, op_t_n: FTN, op_n_t: FNT, op_n_n: FNN, op_n_n_checked: Option, op_assign: Option<(FATT, FATN, FANT)>, ) where T: ByteOrderType, FTT: Fn(T, T) -> T, FTN: Fn(T, T::Native) -> T, FNT: Fn(T::Native, T) -> T, FNN: Fn(T::Native, T::Native) -> T::Native, FNNChecked: Fn(T::Native, T::Native) -> Option, FATT: Fn(&mut T, T), FATN: Fn(&mut T, T::Native), FANT: Fn(&mut T::Native, T), { 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_n_n_checked, Some(checked) if checked(n0, n1).is_none()) { continue; } let t_t_res = op_t_t(t0, t1); let t_n_res = op_t_n(t0, n1); let n_t_res = op_n_t(n0, t1); let n_n_res = op_n_n(n0, n1); // For `f32` and `f64`, NaN values are not considered equal to // themselves. We store `Option`/`Option` and store // NaN as `None` so they can still be compared. let val_or_none = |t: T| (!T::Native::is_nan(t.get())).then(|| t.get()); let t_t_res = val_or_none(t_t_res); let t_n_res = val_or_none(t_n_res); let n_t_res = val_or_none(n_t_res); let n_n_res = (!T::Native::is_nan(n_n_res)).then(|| n_n_res); assert_eq!(t_t_res, n_n_res); assert_eq!(t_n_res, n_n_res); assert_eq!(n_t_res, n_n_res); if let Some((op_assign_t_t, op_assign_t_n, op_assign_n_t)) = &op_assign { let mut t_t_res = t0; op_assign_t_t(&mut t_t_res, t1); let mut t_n_res = t0; op_assign_t_n(&mut t_n_res, n1); let mut n_t_res = n0; op_assign_n_t(&mut n_t_res, t1); // For `f32` and `f64`, NaN values are not considered equal to // themselves. We store `Option`/`Option` and store // NaN as `None` so they can still be compared. let t_t_res = val_or_none(t_t_res); let t_n_res = val_or_none(t_n_res); let n_t_res = (!T::Native::is_nan(n_t_res)).then(|| n_t_res); assert_eq!(t_t_res, n_n_res); assert_eq!(t_n_res, n_n_res); assert_eq!(n_t_res, n_n_res); } } } macro_rules! test { ( @binary $trait:ident, $method:ident $([$checked_method:ident])?, $trait_assign:ident, $method_assign:ident, $($call_for_macros:ident),* ) => {{ fn t() where T: ByteOrderType, T: core::ops::$trait, T: core::ops::$trait, T::Native: core::ops::$trait, T::Native: core::ops::$trait, T: core::ops::$trait_assign, T: core::ops::$trait_assign, T::Native: core::ops::$trait_assign, T::Native: core::ops::$trait_assign, { test::( core::ops::$trait::$method, core::ops::$trait::$method, core::ops::$trait::$method, core::ops::$trait::$method, { #[allow(unused_mut, unused_assignments)] let mut op_native_checked = None:: Option>; $( op_native_checked = Some(T::Native::$checked_method); )? op_native_checked }, Some(( >::$method_assign, >::$method_assign, >::$method_assign )), ); } $( $call_for_macros!(t, NativeEndian); $call_for_macros!(t, NonNativeEndian); )* }}; ( @unary $trait:ident, $method:ident, $($call_for_macros:ident),* ) => {{ fn t() where T: ByteOrderType, T: core::ops::$trait, T::Native: core::ops::$trait, { test::( |slf, _rhs| core::ops::$trait::$method(slf), |slf, _rhs| core::ops::$trait::$method(slf), |slf, _rhs| core::ops::$trait::$method(slf).into(), |slf, _rhs| core::ops::$trait::$method(slf), None:: Option>, None::<(fn(&mut T, T), fn(&mut T, T::Native), fn(&mut T::Native, T))>, ); } $( $call_for_macros!(t, NativeEndian); $call_for_macros!(t, NonNativeEndian); )* }}; } test!(@binary Add, add[checked_add], AddAssign, add_assign, call_for_all_types); test!(@binary Div, div[checked_div], DivAssign, div_assign, call_for_all_types); test!(@binary Mul, mul[checked_mul], MulAssign, mul_assign, call_for_all_types); test!(@binary Rem, rem[checked_rem], RemAssign, rem_assign, call_for_all_types); test!(@binary Sub, sub[checked_sub], SubAssign, sub_assign, call_for_all_types); test!(@binary BitAnd, bitand, BitAndAssign, bitand_assign, call_for_unsigned_types, call_for_signed_types); test!(@binary BitOr, bitor, BitOrAssign, bitor_assign, call_for_unsigned_types, call_for_signed_types); test!(@binary BitXor, bitxor, BitXorAssign, bitxor_assign, call_for_unsigned_types, call_for_signed_types); test!(@binary Shl, shl[checked_shl], ShlAssign, shl_assign, call_for_unsigned_types, call_for_signed_types); test!(@binary Shr, shr[checked_shr], ShrAssign, shr_assign, 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::::new(10); assert_eq!(format!("{:?}", val), "U16(10)"); assert_eq!(format!("{:03?}", val), "U16(010)"); assert_eq!(format!("{:x?}", val), "U16(a)"); } }