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//! Types for compile-time and run-time endianness.
use crate::pod::Pod;
use core::fmt::{self, Debug};
use core::marker::PhantomData;
/// A trait for using an endianness specification.
///
/// Provides methods for converting between the specified endianness and
/// the native endianness of the target machine.
///
/// This trait does not require that the endianness is known at compile time.
pub trait Endian: Debug + Default + Clone + Copy + PartialEq + Eq + 'static {
/// Construct a specification for the endianness of some values.
///
/// Returns `None` if the type does not support specifying the given endianness.
fn from_big_endian(big_endian: bool) -> Option<Self>;
/// Construct a specification for the endianness of some values.
///
/// Returns `None` if the type does not support specifying the given endianness.
fn from_little_endian(little_endian: bool) -> Option<Self> {
Self::from_big_endian(!little_endian)
}
/// Return true for big endian byte order.
fn is_big_endian(self) -> bool;
/// Return true for little endian byte order.
#[inline]
fn is_little_endian(self) -> bool {
!self.is_big_endian()
}
/// Converts an unsigned 16 bit integer to native endian.
#[inline]
fn read_u16(self, n: u16) -> u16 {
if self.is_big_endian() {
u16::from_be(n)
} else {
u16::from_le(n)
}
}
/// Converts an unsigned 32 bit integer to native endian.
#[inline]
fn read_u32(self, n: u32) -> u32 {
if self.is_big_endian() {
u32::from_be(n)
} else {
u32::from_le(n)
}
}
/// Converts an unsigned 64 bit integer to native endian.
#[inline]
fn read_u64(self, n: u64) -> u64 {
if self.is_big_endian() {
u64::from_be(n)
} else {
u64::from_le(n)
}
}
/// Converts a signed 16 bit integer to native endian.
#[inline]
fn read_i16(self, n: i16) -> i16 {
if self.is_big_endian() {
i16::from_be(n)
} else {
i16::from_le(n)
}
}
/// Converts a signed 32 bit integer to native endian.
#[inline]
fn read_i32(self, n: i32) -> i32 {
if self.is_big_endian() {
i32::from_be(n)
} else {
i32::from_le(n)
}
}
/// Converts a signed 64 bit integer to native endian.
#[inline]
fn read_i64(self, n: i64) -> i64 {
if self.is_big_endian() {
i64::from_be(n)
} else {
i64::from_le(n)
}
}
/// Converts an unaligned unsigned 16 bit integer to native endian.
#[inline]
fn read_u16_bytes(self, n: [u8; 2]) -> u16 {
if self.is_big_endian() {
u16::from_be_bytes(n)
} else {
u16::from_le_bytes(n)
}
}
/// Converts an unaligned unsigned 32 bit integer to native endian.
#[inline]
fn read_u32_bytes(self, n: [u8; 4]) -> u32 {
if self.is_big_endian() {
u32::from_be_bytes(n)
} else {
u32::from_le_bytes(n)
}
}
/// Converts an unaligned unsigned 64 bit integer to native endian.
#[inline]
fn read_u64_bytes(self, n: [u8; 8]) -> u64 {
if self.is_big_endian() {
u64::from_be_bytes(n)
} else {
u64::from_le_bytes(n)
}
}
/// Converts an unaligned signed 16 bit integer to native endian.
#[inline]
fn read_i16_bytes(self, n: [u8; 2]) -> i16 {
if self.is_big_endian() {
i16::from_be_bytes(n)
} else {
i16::from_le_bytes(n)
}
}
/// Converts an unaligned signed 32 bit integer to native endian.
#[inline]
fn read_i32_bytes(self, n: [u8; 4]) -> i32 {
if self.is_big_endian() {
i32::from_be_bytes(n)
} else {
i32::from_le_bytes(n)
}
}
/// Converts an unaligned signed 64 bit integer to native endian.
#[inline]
fn read_i64_bytes(self, n: [u8; 8]) -> i64 {
if self.is_big_endian() {
i64::from_be_bytes(n)
} else {
i64::from_le_bytes(n)
}
}
/// Converts an unsigned 16 bit integer from native endian.
#[inline]
fn write_u16(self, n: u16) -> u16 {
if self.is_big_endian() {
u16::to_be(n)
} else {
u16::to_le(n)
}
}
/// Converts an unsigned 32 bit integer from native endian.
#[inline]
fn write_u32(self, n: u32) -> u32 {
if self.is_big_endian() {
u32::to_be(n)
} else {
u32::to_le(n)
}
}
/// Converts an unsigned 64 bit integer from native endian.
#[inline]
fn write_u64(self, n: u64) -> u64 {
if self.is_big_endian() {
u64::to_be(n)
} else {
u64::to_le(n)
}
}
/// Converts a signed 16 bit integer from native endian.
#[inline]
fn write_i16(self, n: i16) -> i16 {
if self.is_big_endian() {
i16::to_be(n)
} else {
i16::to_le(n)
}
}
/// Converts a signed 32 bit integer from native endian.
#[inline]
fn write_i32(self, n: i32) -> i32 {
if self.is_big_endian() {
i32::to_be(n)
} else {
i32::to_le(n)
}
}
/// Converts a signed 64 bit integer from native endian.
#[inline]
fn write_i64(self, n: i64) -> i64 {
if self.is_big_endian() {
i64::to_be(n)
} else {
i64::to_le(n)
}
}
/// Converts an unaligned unsigned 16 bit integer from native endian.
#[inline]
fn write_u16_bytes(self, n: u16) -> [u8; 2] {
if self.is_big_endian() {
u16::to_be_bytes(n)
} else {
u16::to_le_bytes(n)
}
}
/// Converts an unaligned unsigned 32 bit integer from native endian.
#[inline]
fn write_u32_bytes(self, n: u32) -> [u8; 4] {
if self.is_big_endian() {
u32::to_be_bytes(n)
} else {
u32::to_le_bytes(n)
}
}
/// Converts an unaligned unsigned 64 bit integer from native endian.
#[inline]
fn write_u64_bytes(self, n: u64) -> [u8; 8] {
if self.is_big_endian() {
u64::to_be_bytes(n)
} else {
u64::to_le_bytes(n)
}
}
/// Converts an unaligned signed 16 bit integer from native endian.
#[inline]
fn write_i16_bytes(self, n: i16) -> [u8; 2] {
if self.is_big_endian() {
i16::to_be_bytes(n)
} else {
i16::to_le_bytes(n)
}
}
/// Converts an unaligned signed 32 bit integer from native endian.
#[inline]
fn write_i32_bytes(self, n: i32) -> [u8; 4] {
if self.is_big_endian() {
i32::to_be_bytes(n)
} else {
i32::to_le_bytes(n)
}
}
/// Converts an unaligned signed 64 bit integer from native endian.
#[inline]
fn write_i64_bytes(self, n: i64) -> [u8; 8] {
if self.is_big_endian() {
i64::to_be_bytes(n)
} else {
i64::to_le_bytes(n)
}
}
}
/// An endianness that is selectable at run-time.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub enum Endianness {
/// Little endian byte order.
Little,
/// Big endian byte order.
Big,
}
impl Default for Endianness {
#[cfg(target_endian = "little")]
#[inline]
fn default() -> Endianness {
Endianness::Little
}
#[cfg(target_endian = "big")]
#[inline]
fn default() -> Endianness {
Endianness::Big
}
}
impl Endian for Endianness {
#[inline]
fn from_big_endian(big_endian: bool) -> Option<Self> {
Some(if big_endian {
Endianness::Big
} else {
Endianness::Little
})
}
#[inline]
fn is_big_endian(self) -> bool {
self != Endianness::Little
}
}
/// Compile-time little endian byte order.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub struct LittleEndian;
impl Default for LittleEndian {
#[inline]
fn default() -> LittleEndian {
LittleEndian
}
}
impl Endian for LittleEndian {
#[inline]
fn from_big_endian(big_endian: bool) -> Option<Self> {
if big_endian {
None
} else {
Some(LittleEndian)
}
}
#[inline]
fn is_big_endian(self) -> bool {
false
}
}
/// Compile-time big endian byte order.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub struct BigEndian;
impl Default for BigEndian {
#[inline]
fn default() -> BigEndian {
BigEndian
}
}
impl Endian for BigEndian {
#[inline]
fn from_big_endian(big_endian: bool) -> Option<Self> {
if big_endian {
Some(BigEndian)
} else {
None
}
}
#[inline]
fn is_big_endian(self) -> bool {
true
}
}
/// The native endianness for the target platform.
#[cfg(target_endian = "little")]
pub type NativeEndian = LittleEndian;
#[cfg(target_endian = "little")]
#[allow(non_upper_case_globals)]
#[doc(hidden)]
pub const NativeEndian: LittleEndian = LittleEndian;
/// The native endianness for the target platform.
#[cfg(target_endian = "big")]
pub type NativeEndian = BigEndian;
#[cfg(target_endian = "big")]
#[allow(non_upper_case_globals)]
#[doc(hidden)]
pub const NativeEndian: BigEndian = BigEndian;
macro_rules! unsafe_impl_endian_pod {
($($struct_name:ident),+ $(,)?) => {
$(
unsafe impl<E: Endian> Pod for $struct_name<E> { }
)+
}
}
#[cfg(not(feature = "unaligned"))]
mod aligned {
use super::{fmt, Endian, PhantomData, Pod};
/// A `u16` value with an externally specified endianness of type `E`.
#[derive(Default, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
#[repr(transparent)]
pub struct U16<E: Endian>(u16, PhantomData<E>);
impl<E: Endian> U16<E> {
/// Construct a new value given bytes that already have the required endianness.
pub fn from_bytes(n: [u8; 2]) -> Self {
Self(u16::from_ne_bytes(n), PhantomData)
}
/// Construct a new value given a native endian value.
pub fn new(e: E, n: u16) -> Self {
Self(e.write_u16(n), PhantomData)
}
/// Return the value as a native endian value.
pub fn get(self, e: E) -> u16 {
e.read_u16(self.0)
}
/// Set the value given a native endian value.
pub fn set(&mut self, e: E, n: u16) {
self.0 = e.write_u16(n);
}
}
/// A `u32` value with an externally specified endianness of type `E`.
#[derive(Default, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
#[repr(transparent)]
pub struct U32<E: Endian>(u32, PhantomData<E>);
impl<E: Endian> U32<E> {
/// Construct a new value given bytes that already have the required endianness.
pub fn from_bytes(n: [u8; 4]) -> Self {
Self(u32::from_ne_bytes(n), PhantomData)
}
/// Construct a new value given a native endian value.
pub fn new(e: E, n: u32) -> Self {
Self(e.write_u32(n), PhantomData)
}
/// Return the value as a native endian value.
pub fn get(self, e: E) -> u32 {
e.read_u32(self.0)
}
/// Set the value given a native endian value.
pub fn set(&mut self, e: E, n: u32) {
self.0 = e.write_u32(n);
}
}
/// A `u64` value with an externally specified endianness of type `E`.
#[derive(Default, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
#[repr(transparent)]
pub struct U64<E: Endian>(u64, PhantomData<E>);
impl<E: Endian> U64<E> {
/// Construct a new value given bytes that already have the required endianness.
pub fn from_bytes(n: [u8; 8]) -> Self {
Self(u64::from_ne_bytes(n), PhantomData)
}
/// Construct a new value given a native endian value.
pub fn new(e: E, n: u64) -> Self {
Self(e.write_u64(n), PhantomData)
}
/// Return the value as a native endian value.
pub fn get(self, e: E) -> u64 {
e.read_u64(self.0)
}
/// Set the value given a native endian value.
pub fn set(&mut self, e: E, n: u64) {
self.0 = e.write_u64(n);
}
}
/// An `i16` value with an externally specified endianness of type `E`.
#[derive(Default, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
#[repr(transparent)]
pub struct I16<E: Endian>(i16, PhantomData<E>);
impl<E: Endian> I16<E> {
/// Construct a new value given bytes that already have the required endianness.
pub fn from_bytes(n: [u8; 2]) -> Self {
Self(i16::from_ne_bytes(n), PhantomData)
}
/// Construct a new value given a native endian value.
pub fn new(e: E, n: i16) -> Self {
Self(e.write_i16(n), PhantomData)
}
/// Return the value as a native endian value.
pub fn get(self, e: E) -> i16 {
e.read_i16(self.0)
}
/// Set the value given a native endian value.
pub fn set(&mut self, e: E, n: i16) {
self.0 = e.write_i16(n);
}
}
/// An `i32` value with an externally specified endianness of type `E`.
#[derive(Default, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
#[repr(transparent)]
pub struct I32<E: Endian>(i32, PhantomData<E>);
impl<E: Endian> I32<E> {
/// Construct a new value given bytes that already have the required endianness.
pub fn from_bytes(n: [u8; 4]) -> Self {
Self(i32::from_ne_bytes(n), PhantomData)
}
/// Construct a new value given a native endian value.
pub fn new(e: E, n: i32) -> Self {
Self(e.write_i32(n), PhantomData)
}
/// Return the value as a native endian value.
pub fn get(self, e: E) -> i32 {
e.read_i32(self.0)
}
/// Set the value given a native endian value.
pub fn set(&mut self, e: E, n: i32) {
self.0 = e.write_i32(n);
}
}
/// An `i64` value with an externally specified endianness of type `E`.
#[derive(Default, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
#[repr(transparent)]
pub struct I64<E: Endian>(i64, PhantomData<E>);
impl<E: Endian> I64<E> {
/// Construct a new value given bytes that already have the required endianness.
pub fn from_bytes(n: [u8; 8]) -> Self {
Self(i64::from_ne_bytes(n), PhantomData)
}
/// Construct a new value given a native endian value.
pub fn new(e: E, n: i64) -> Self {
Self(e.write_i64(n), PhantomData)
}
/// Return the value as a native endian value.
pub fn get(self, e: E) -> i64 {
e.read_i64(self.0)
}
/// Set the value given a native endian value.
pub fn set(&mut self, e: E, n: i64) {
self.0 = e.write_i64(n);
}
}
impl<E: Endian> fmt::Debug for U16<E> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "U16({:x})", self.0)
}
}
impl<E: Endian> fmt::Debug for U32<E> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "U32({:x})", self.0)
}
}
impl<E: Endian> fmt::Debug for U64<E> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "U64({:x})", self.0)
}
}
impl<E: Endian> fmt::Debug for I16<E> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "I16({:x})", self.0)
}
}
impl<E: Endian> fmt::Debug for I32<E> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "I32({:x})", self.0)
}
}
impl<E: Endian> fmt::Debug for I64<E> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "I64({:x})", self.0)
}
}
unsafe_impl_endian_pod!(U16, U32, U64, I16, I32, I64);
}
#[cfg(not(feature = "unaligned"))]
pub use aligned::*;
/// A `u16` value with an externally specified endianness of type `E`.
#[cfg(feature = "unaligned")]
pub type U16<E> = U16Bytes<E>;
/// A `u32` value with an externally specified endianness of type `E`.
#[cfg(feature = "unaligned")]
pub type U32<E> = U32Bytes<E>;
/// A `u64` value with an externally specified endianness of type `E`.
#[cfg(feature = "unaligned")]
pub type U64<E> = U64Bytes<E>;
/// An `i16` value with an externally specified endianness of type `E`.
#[cfg(feature = "unaligned")]
pub type I16<E> = I16Bytes<E>;
/// An `i32` value with an externally specified endianness of type `E`.
#[cfg(feature = "unaligned")]
pub type I32<E> = I32Bytes<E>;
/// An `i64` value with an externally specified endianness of type `E`.
#[cfg(feature = "unaligned")]
pub type I64<E> = I64Bytes<E>;
/// An unaligned `u16` value with an externally specified endianness of type `E`.
#[derive(Default, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
#[repr(transparent)]
pub struct U16Bytes<E: Endian>([u8; 2], PhantomData<E>);
impl<E: Endian> U16Bytes<E> {
/// Construct a new value given bytes that already have the required endianness.
pub fn from_bytes(n: [u8; 2]) -> Self {
Self(n, PhantomData)
}
/// Construct a new value given a native endian value.
pub fn new(e: E, n: u16) -> Self {
Self(e.write_u16_bytes(n), PhantomData)
}
/// Return the value as a native endian value.
pub fn get(self, e: E) -> u16 {
e.read_u16_bytes(self.0)
}
/// Set the value given a native endian value.
pub fn set(&mut self, e: E, n: u16) {
self.0 = e.write_u16_bytes(n);
}
}
/// An unaligned `u32` value with an externally specified endianness of type `E`.
#[derive(Default, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
#[repr(transparent)]
pub struct U32Bytes<E: Endian>([u8; 4], PhantomData<E>);
impl<E: Endian> U32Bytes<E> {
/// Construct a new value given bytes that already have the required endianness.
pub fn from_bytes(n: [u8; 4]) -> Self {
Self(n, PhantomData)
}
/// Construct a new value given a native endian value.
pub fn new(e: E, n: u32) -> Self {
Self(e.write_u32_bytes(n), PhantomData)
}
/// Return the value as a native endian value.
pub fn get(self, e: E) -> u32 {
e.read_u32_bytes(self.0)
}
/// Set the value given a native endian value.
pub fn set(&mut self, e: E, n: u32) {
self.0 = e.write_u32_bytes(n);
}
}
/// An unaligned `u64` value with an externally specified endianness of type `E`.
#[derive(Default, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
#[repr(transparent)]
pub struct U64Bytes<E: Endian>([u8; 8], PhantomData<E>);
impl<E: Endian> U64Bytes<E> {
/// Construct a new value given bytes that already have the required endianness.
pub fn from_bytes(n: [u8; 8]) -> Self {
Self(n, PhantomData)
}
/// Construct a new value given a native endian value.
pub fn new(e: E, n: u64) -> Self {
Self(e.write_u64_bytes(n), PhantomData)
}
/// Return the value as a native endian value.
pub fn get(self, e: E) -> u64 {
e.read_u64_bytes(self.0)
}
/// Set the value given a native endian value.
pub fn set(&mut self, e: E, n: u64) {
self.0 = e.write_u64_bytes(n);
}
}
/// An unaligned `i16` value with an externally specified endianness of type `E`.
#[derive(Default, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
#[repr(transparent)]
pub struct I16Bytes<E: Endian>([u8; 2], PhantomData<E>);
impl<E: Endian> I16Bytes<E> {
/// Construct a new value given bytes that already have the required endianness.
pub fn from_bytes(n: [u8; 2]) -> Self {
Self(n, PhantomData)
}
/// Construct a new value given a native endian value.
pub fn new(e: E, n: i16) -> Self {
Self(e.write_i16_bytes(n), PhantomData)
}
/// Return the value as a native endian value.
pub fn get(self, e: E) -> i16 {
e.read_i16_bytes(self.0)
}
/// Set the value given a native endian value.
pub fn set(&mut self, e: E, n: i16) {
self.0 = e.write_i16_bytes(n);
}
}
/// An unaligned `i32` value with an externally specified endianness of type `E`.
#[derive(Default, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
#[repr(transparent)]
pub struct I32Bytes<E: Endian>([u8; 4], PhantomData<E>);
impl<E: Endian> I32Bytes<E> {
/// Construct a new value given bytes that already have the required endianness.
pub fn from_bytes(n: [u8; 4]) -> Self {
Self(n, PhantomData)
}
/// Construct a new value given a native endian value.
pub fn new(e: E, n: i32) -> Self {
Self(e.write_i32_bytes(n), PhantomData)
}
/// Return the value as a native endian value.
pub fn get(self, e: E) -> i32 {
e.read_i32_bytes(self.0)
}
/// Set the value given a native endian value.
pub fn set(&mut self, e: E, n: i32) {
self.0 = e.write_i32_bytes(n);
}
}
/// An unaligned `i64` value with an externally specified endianness of type `E`.
#[derive(Default, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
#[repr(transparent)]
pub struct I64Bytes<E: Endian>([u8; 8], PhantomData<E>);
impl<E: Endian> I64Bytes<E> {
/// Construct a new value given bytes that already have the required endianness.
pub fn from_bytes(n: [u8; 8]) -> Self {
Self(n, PhantomData)
}
/// Construct a new value given a native endian value.
pub fn new(e: E, n: i64) -> Self {
Self(e.write_i64_bytes(n), PhantomData)
}
/// Return the value as a native endian value.
pub fn get(self, e: E) -> i64 {
e.read_i64_bytes(self.0)
}
/// Set the value given a native endian value.
pub fn set(&mut self, e: E, n: i64) {
self.0 = e.write_i64_bytes(n);
}
}
impl<E: Endian> fmt::Debug for U16Bytes<E> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "U16({:x}, {:x})", self.0[0], self.0[1],)
}
}
impl<E: Endian> fmt::Debug for U32Bytes<E> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(
f,
"U32({:x}, {:x}, {:x}, {:x})",
self.0[0], self.0[1], self.0[2], self.0[3],
)
}
}
impl<E: Endian> fmt::Debug for U64Bytes<E> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(
f,
"U64({:x}, {:x}, {:x}, {:x}, {:x}, {:x}, {:x}, {:x})",
self.0[0], self.0[1], self.0[2], self.0[3], self.0[4], self.0[5], self.0[6], self.0[7],
)
}
}
impl<E: Endian> fmt::Debug for I16Bytes<E> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "I16({:x}, {:x})", self.0[0], self.0[1],)
}
}
impl<E: Endian> fmt::Debug for I32Bytes<E> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(
f,
"I32({:x}, {:x}, {:x}, {:x})",
self.0[0], self.0[1], self.0[2], self.0[3],
)
}
}
impl<E: Endian> fmt::Debug for I64Bytes<E> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(
f,
"I64({:x}, {:x}, {:x}, {:x}, {:x}, {:x}, {:x}, {:x})",
self.0[0], self.0[1], self.0[2], self.0[3], self.0[4], self.0[5], self.0[6], self.0[7],
)
}
}
unsafe_impl_endian_pod!(U16Bytes, U32Bytes, U64Bytes, I16Bytes, I32Bytes, I64Bytes);