//! This module contains functions for querying the size and alignment of
//! types, initializing and manipulating memory.
+use clone::Clone;
use ptr;
use intrinsics;
use intrinsics::{bswap16, bswap32, bswap64};
ptr::write(dst, src)
}
-/// Convert an u16 to little endian from the target's endianness.
-///
-/// On little endian, this is a no-op. On big endian, the bytes are swapped.
-#[cfg(target_endian = "little")] #[inline] pub fn to_le16(x: u16) -> u16 { x }
+/// A type that can have its bytes re-ordered.
+pub trait ByteOrder: Clone {
+ /// Reverses the byte order of the value.
+ ///
+ /// # Example
+ ///
+ /// ```rust
+ /// use std::mem::ByteOrder;
+ ///
+ /// let n = 0x0123456789ABCDEFu64;
+ /// let m = 0xEFCDAB8967452301u64;
+ ///
+ /// assert_eq!(n.swap_bytes(), m);
+ /// ```
+ fn swap_bytes(&self) -> Self;
+
+ /// Convert a value from big endian to the target's endianness.
+ ///
+ /// On big endian this is a no-op. On little endian the bytes are swapped.
+ ///
+ /// # Example
+ ///
+ /// ```rust
+ /// use std::mem::ByteOrder;
+ ///
+ /// let n = 0x0123456789ABCDEFu64;
+ ///
+ /// if cfg!(target_endian = "big") {
+ /// assert_eq!(ByteOrder::from_big_endian(n), n)
+ /// } else {
+ /// assert_eq!(ByteOrder::from_big_endian(n), n.swap_bytes())
+ /// }
+ /// ```
+ #[inline]
+ fn from_big_endian(x: Self) -> Self {
+ if cfg!(target_endian = "big") { x } else { x.swap_bytes() }
+ }
-/// Convert an u16 to little endian from the target's endianness.
-///
-/// On little endian, this is a no-op. On big endian, the bytes are swapped.
-#[cfg(target_endian = "big")] #[inline] #[stable]
-pub fn to_le16(x: u16) -> u16 { unsafe { bswap16(x) } }
+ /// Convert a value from little endian to the target's endianness.
+ ///
+ /// On little endian this is a no-op. On big endian the bytes are swapped.
+ ///
+ /// # Example
+ ///
+ /// ```rust
+ /// use std::mem::ByteOrder;
+ ///
+ /// let n = 0x0123456789ABCDEFu64;
+ ///
+ /// if cfg!(target_endian = "little") {
+ /// assert_eq!(ByteOrder::from_little_endian(n), n)
+ /// } else {
+ /// assert_eq!(ByteOrder::from_little_endian(n), n.swap_bytes())
+ /// }
+ /// ```
+ #[inline]
+ fn from_little_endian(x: Self) -> Self {
+ if cfg!(target_endian = "little") { x } else { x.swap_bytes() }
+ }
-/// Convert an u32 to little endian from the target's endianness.
-///
-/// On little endian, this is a no-op. On big endian, the bytes are swapped.
-#[cfg(target_endian = "little")] #[inline] #[stable]
-pub fn to_le32(x: u32) -> u32 { x }
+ /// Convert the value to big endian from the target's endianness.
+ ///
+ /// On big endian this is a no-op. On little endian the bytes are swapped.
+ ///
+ /// # Example
+ ///
+ /// ```rust
+ /// use std::mem::ByteOrder;
+ ///
+ /// let n = 0x0123456789ABCDEFu64;
+ ///
+ /// if cfg!(target_endian = "big") {
+ /// assert_eq!(n.to_big_endian(), n)
+ /// } else {
+ /// assert_eq!(n.to_big_endian(), n.swap_bytes())
+ /// }
+ /// ```
+ #[inline]
+ fn to_big_endian(&self) -> Self {
+ if cfg!(target_endian = "big") { self.clone() } else { self.swap_bytes() }
+ }
-/// Convert an u32 to little endian from the target's endianness.
+ /// Convert the value to little endian from the target's endianness.
+ ///
+ /// On little endian this is a no-op. On big endian the bytes are swapped.
+ ///
+ /// # Example
+ ///
+ /// ```rust
+ /// use std::mem::ByteOrder;
+ ///
+ /// let n = 0x0123456789ABCDEFu64;
+ ///
+ /// if cfg!(target_endian = "little") {
+ /// assert_eq!(n.to_little_endian(), n)
+ /// } else {
+ /// assert_eq!(n.to_little_endian(), n.swap_bytes())
+ /// }
+ /// ```
+ #[inline]
+ fn to_little_endian(&self) -> Self {
+ if cfg!(target_endian = "little") { self.clone() } else { self.swap_bytes() }
+ }
+}
+
+impl ByteOrder for u8 {
+ #[inline]
+ fn swap_bytes(&self) -> u8 {
+ *self // swapping a single byte does nothing
+ }
+}
+
+impl ByteOrder for u16 {
+ #[inline]
+ fn swap_bytes(&self) -> u16 {
+ unsafe { intrinsics::bswap16(*self) }
+ }
+}
+
+impl ByteOrder for u32 {
+ #[inline]
+ fn swap_bytes(&self) -> u32 {
+ unsafe { intrinsics::bswap32(*self) }
+ }
+}
+
+impl ByteOrder for u64 {
+ #[inline]
+ fn swap_bytes(&self) -> u64 {
+ unsafe { intrinsics::bswap64(*self) }
+ }
+}
+
+#[cfg(target_word_size = "32")]
+impl ByteOrder for uint {
+ #[inline]
+ fn swap_bytes(&self) -> uint {
+ (*self as u32).swap_bytes() as uint
+ }
+}
+
+#[cfg(target_word_size = "64")]
+impl ByteOrder for uint {
+ #[inline]
+ fn swap_bytes(&self) -> uint {
+ (*self as u64).swap_bytes() as uint
+ }
+}
+
+/// Convert an u16 to little endian from the target's endianness.
///
/// On little endian, this is a no-op. On big endian, the bytes are swapped.
-#[cfg(target_endian = "big")] #[inline] #[stable]
-pub fn to_le32(x: u32) -> u32 { unsafe { bswap32(x) } }
+#[inline]
+#[stable]
+pub fn to_le16(x: u16) -> u16 { x.to_little_endian() }
-/// Convert an u64 to little endian from the target's endianness.
+/// Convert an u32 to little endian from the target's endianness.
///
/// On little endian, this is a no-op. On big endian, the bytes are swapped.
-#[cfg(target_endian = "little")] #[inline] #[stable]
-pub fn to_le64(x: u64) -> u64 { x }
+#[inline]
+#[stable]
+pub fn to_le32(x: u32) -> u32 { x.to_little_endian() }
/// Convert an u64 to little endian from the target's endianness.
///
/// On little endian, this is a no-op. On big endian, the bytes are swapped.
-#[cfg(target_endian = "big")] #[inline] #[stable]
-pub fn to_le64(x: u64) -> u64 { unsafe { bswap64(x) } }
-
-
-/// Convert an u16 to big endian from the target's endianness.
-///
-/// On big endian, this is a no-op. On little endian, the bytes are swapped.
-#[cfg(target_endian = "little")] #[inline] #[stable]
-pub fn to_be16(x: u16) -> u16 { unsafe { bswap16(x) } }
+#[inline]
+#[stable]
+pub fn to_le64(x: u64) -> u64 { x.to_little_endian() }
/// Convert an u16 to big endian from the target's endianness.
///
/// On big endian, this is a no-op. On little endian, the bytes are swapped.
-#[cfg(target_endian = "big")] #[inline] #[stable]
-pub fn to_be16(x: u16) -> u16 { x }
-
-/// Convert an u32 to big endian from the target's endianness.
-///
-/// On big endian, this is a no-op. On little endian, the bytes are swapped.
-#[cfg(target_endian = "little")] #[inline] #[stable]
-pub fn to_be32(x: u32) -> u32 { unsafe { bswap32(x) } }
+#[inline]
+#[stable]
+pub fn to_be16(x: u16) -> u16 { x.to_big_endian() }
/// Convert an u32 to big endian from the target's endianness.
///
/// On big endian, this is a no-op. On little endian, the bytes are swapped.
-#[cfg(target_endian = "big")] #[inline] #[stable]
-pub fn to_be32(x: u32) -> u32 { x }
-
-/// Convert an u64 to big endian from the target's endianness.
-///
-/// On big endian, this is a no-op. On little endian, the bytes are swapped.
-#[cfg(target_endian = "little")] #[inline] #[stable]
-pub fn to_be64(x: u64) -> u64 { unsafe { bswap64(x) } }
+#[inline]
+#[stable]
+pub fn to_be32(x: u32) -> u32 { x.to_big_endian() }
/// Convert an u64 to big endian from the target's endianness.
///
/// On big endian, this is a no-op. On little endian, the bytes are swapped.
-#[cfg(target_endian = "big")] #[inline] #[stable]
-pub fn to_be64(x: u64) -> u64 { x }
-
-
-/// Convert an u16 from little endian to the target's endianness.
-///
-/// On little endian, this is a no-op. On big endian, the bytes are swapped.
-#[cfg(target_endian = "little")] #[inline] #[stable]
-pub fn from_le16(x: u16) -> u16 { x }
+#[inline]
+#[stable]
+pub fn to_be64(x: u64) -> u64 { x.to_big_endian() }
/// Convert an u16 from little endian to the target's endianness.
///
/// On little endian, this is a no-op. On big endian, the bytes are swapped.
-#[cfg(target_endian = "big")] #[inline] #[stable]
-pub fn from_le16(x: u16) -> u16 { unsafe { bswap16(x) } }
-
-/// Convert an u32 from little endian to the target's endianness.
-///
-/// On little endian, this is a no-op. On big endian, the bytes are swapped.
-#[cfg(target_endian = "little")] #[inline] #[stable]
-pub fn from_le32(x: u32) -> u32 { x }
+#[inline]
+#[stable]
+pub fn from_le16(x: u16) -> u16 { ByteOrder::from_little_endian(x) }
/// Convert an u32 from little endian to the target's endianness.
///
/// On little endian, this is a no-op. On big endian, the bytes are swapped.
-#[cfg(target_endian = "big")] #[inline] #[stable]
-pub fn from_le32(x: u32) -> u32 { unsafe { bswap32(x) } }
-
-/// Convert an u64 from little endian to the target's endianness.
-///
-/// On little endian, this is a no-op. On big endian, the bytes are swapped.
-#[cfg(target_endian = "little")] #[inline] #[stable]
-pub fn from_le64(x: u64) -> u64 { x }
+#[inline]
+#[stable]
+pub fn from_le32(x: u32) -> u32 { ByteOrder::from_little_endian(x) }
/// Convert an u64 from little endian to the target's endianness.
///
/// On little endian, this is a no-op. On big endian, the bytes are swapped.
-#[cfg(target_endian = "big")] #[inline] #[stable]
-pub fn from_le64(x: u64) -> u64 { unsafe { bswap64(x) } }
-
-
-/// Convert an u16 from big endian to the target's endianness.
-///
-/// On big endian, this is a no-op. On little endian, the bytes are swapped.
-#[cfg(target_endian = "little")] #[inline] #[stable]
-pub fn from_be16(x: u16) -> u16 { unsafe { bswap16(x) } }
+#[inline]
+#[stable]
+pub fn from_le64(x: u64) -> u64 { ByteOrder::from_little_endian(x) }
/// Convert an u16 from big endian to the target's endianness.
///
/// On big endian, this is a no-op. On little endian, the bytes are swapped.
-#[cfg(target_endian = "big")] #[inline] #[stable]
-pub fn from_be16(x: u16) -> u16 { x }
-
-/// Convert an u32 from big endian to the target's endianness.
-///
-/// On big endian, this is a no-op. On little endian, the bytes are swapped.
-#[cfg(target_endian = "little")] #[inline] #[stable]
-pub fn from_be32(x: u32) -> u32 { unsafe { bswap32(x) } }
+#[inline]
+#[stable]
+pub fn from_be16(x: u16) -> u16 { ByteOrder::from_big_endian(x) }
/// Convert an u32 from big endian to the target's endianness.
///
/// On big endian, this is a no-op. On little endian, the bytes are swapped.
-#[cfg(target_endian = "big")] #[inline] #[stable]
-pub fn from_be32(x: u32) -> u32 { x }
-
-/// Convert an u64 from big endian to the target's endianness.
-///
-/// On big endian, this is a no-op. On little endian, the bytes are swapped.
-#[cfg(target_endian = "little")] #[inline] #[stable]
-pub fn from_be64(x: u64) -> u64 { unsafe { bswap64(x) } }
+#[inline]
+#[stable]
+pub fn from_be32(x: u32) -> u32 { ByteOrder::from_big_endian(x) }
/// Convert an u64 from big endian to the target's endianness.
///
/// On big endian, this is a no-op. On little endian, the bytes are swapped.
-#[cfg(target_endian = "big")] #[inline] #[stable]
-pub fn from_be64(x: u64) -> u64 { x }
+#[inline]
+#[stable]
+pub fn from_be64(x: u64) -> u64 { ByteOrder::from_big_endian(x) }
/**
* Swap the values at two mutable locations of the same type, without
assert!(Vec::from_slice([76u8]) == transmute("L".to_string()));
}
}
+
+ macro_rules! test_byte_order {
+ ($T:ident) => {
+ mod $T {
+ use mem::ByteOrder;
+
+ static A: $T = 0b0101100;
+ static B: $T = 0b0100001;
+ static C: $T = 0b1111001;
+
+ static _0: $T = 0;
+ static _1: $T = !0;
+
+ #[test]
+ fn test_swap_bytes() {
+ assert_eq!(A.swap_bytes().swap_bytes(), A);
+ assert_eq!(B.swap_bytes().swap_bytes(), B);
+ assert_eq!(C.swap_bytes().swap_bytes(), C);
+
+ // Swapping these should make no difference
+ assert_eq!(_0.swap_bytes(), _0);
+ assert_eq!(_1.swap_bytes(), _1);
+ }
+
+ #[test]
+ fn test_little_endian() {
+ assert_eq!(ByteOrder::from_little_endian(A.to_little_endian()), A);
+ assert_eq!(ByteOrder::from_little_endian(B.to_little_endian()), B);
+ assert_eq!(ByteOrder::from_little_endian(C.to_little_endian()), C);
+ assert_eq!(ByteOrder::from_little_endian(_0), _0);
+ assert_eq!(ByteOrder::from_little_endian(_1), _1);
+ assert_eq!(_0.to_little_endian(), _0);
+ assert_eq!(_1.to_little_endian(), _1);
+ }
+
+ #[test]
+ fn test_big_endian() {
+ assert_eq!(ByteOrder::from_big_endian(A.to_big_endian()), A);
+ assert_eq!(ByteOrder::from_big_endian(B.to_big_endian()), B);
+ assert_eq!(ByteOrder::from_big_endian(C.to_big_endian()), C);
+ assert_eq!(ByteOrder::from_big_endian(_0), _0);
+ assert_eq!(ByteOrder::from_big_endian(_1), _1);
+ assert_eq!(_0.to_big_endian(), _0);
+ assert_eq!(_1.to_big_endian(), _1);
+ }
+ }
+ }
+ }
+
+ test_byte_order!(u8)
+ test_byte_order!(u16)
+ test_byte_order!(u32)
+ test_byte_order!(u64)
+ test_byte_order!(uint)
}
// FIXME #13642 (these benchmarks should be in another place)
/// ```
fn trailing_zeros(&self) -> Self;
- /// Reverses the byte order of a binary number.
- ///
- /// # Example
- ///
- /// ```rust
- /// use std::num::Bitwise;
- ///
- /// let n = 0x0123456789ABCDEFu64;
- /// let m = 0xEFCDAB8967452301u64;
- /// assert_eq!(n.swap_bytes(), m);
- /// ```
- fn swap_bytes(&self) -> Self;
-
/// Shifts the bits to the left by a specified amount amount, `r`, wrapping
/// the truncated bits to the end of the resulting value.
///
fn rotate_right(&self, r: uint) -> Self;
}
-/// Swapping a single byte does nothing. This is unsafe to be consistent with
-/// the other `bswap` intrinsics.
-#[inline]
-unsafe fn bswap8(x: u8) -> u8 { x }
-
-macro_rules! bitwise_impl(
- ($t:ty, $bits:expr, $co:ident, $lz:ident, $tz:ident, $bs:path) => {
+macro_rules! bitwise_impl {
+ ($t:ty, $bits:expr, $co:path, $lz:path, $tz:path) => {
impl Bitwise for $t {
#[inline]
- fn count_ones(&self) -> $t { unsafe { intrinsics::$co(*self) } }
-
- #[inline]
- fn leading_zeros(&self) -> $t { unsafe { intrinsics::$lz(*self) } }
+ fn count_ones(&self) -> $t { unsafe { $co(*self) } }
#[inline]
- fn trailing_zeros(&self) -> $t { unsafe { intrinsics::$tz(*self) } }
+ fn leading_zeros(&self) -> $t { unsafe { $lz(*self) } }
#[inline]
- fn swap_bytes(&self) -> $t { unsafe { $bs(*self) } }
+ fn trailing_zeros(&self) -> $t { unsafe { $tz(*self) } }
#[inline]
fn rotate_left(&self, r: uint) -> $t {
}
}
}
-)
+}
-macro_rules! bitwise_cast_impl(
- ($t:ty, $t_cast:ty, $bits:expr, $co:ident, $lz:ident, $tz:ident, $bs:path) => {
+macro_rules! bitwise_cast_impl {
+ ($t:ty, $t_cast:ty, $bits:expr, $co:path, $lz:path, $tz:path) => {
impl Bitwise for $t {
#[inline]
- fn count_ones(&self) -> $t { unsafe { intrinsics::$co(*self as $t_cast) as $t } }
+ fn count_ones(&self) -> $t { unsafe { $co(*self as $t_cast) as $t } }
#[inline]
- fn leading_zeros(&self) -> $t { unsafe { intrinsics::$lz(*self as $t_cast) as $t } }
+ fn leading_zeros(&self) -> $t { unsafe { $lz(*self as $t_cast) as $t } }
#[inline]
- fn trailing_zeros(&self) -> $t { unsafe { intrinsics::$tz(*self as $t_cast) as $t } }
-
- #[inline]
- fn swap_bytes(&self) -> $t { unsafe { $bs(*self as $t_cast) as $t } }
+ fn trailing_zeros(&self) -> $t { unsafe { $tz(*self as $t_cast) as $t } }
#[inline]
fn rotate_left(&self, r: uint) -> $t {
}
}
}
-)
+}
#[cfg(target_word_size = "32")]
-bitwise_cast_impl!(uint, u32, 32, ctpop32, ctlz32, cttz32, intrinsics::bswap32)
+bitwise_cast_impl!(uint, u32, 32, intrinsics::ctpop32, intrinsics::ctlz32, intrinsics::cttz32)
#[cfg(target_word_size = "64")]
-bitwise_cast_impl!(uint, u64, 64, ctpop64, ctlz64, cttz64, intrinsics::bswap64)
+bitwise_cast_impl!(uint, u64, 64, intrinsics::ctpop64, intrinsics::ctlz64, intrinsics::cttz64)
-bitwise_impl!(u8, 8, ctpop8, ctlz8, cttz8, bswap8)
-bitwise_impl!(u16, 16, ctpop16, ctlz16, cttz16, intrinsics::bswap16)
-bitwise_impl!(u32, 32, ctpop32, ctlz32, cttz32, intrinsics::bswap32)
-bitwise_impl!(u64, 64, ctpop64, ctlz64, cttz64, intrinsics::bswap64)
+bitwise_impl!(u8, 8, intrinsics::ctpop8, intrinsics::ctlz8, intrinsics::cttz8)
+bitwise_impl!(u16, 16, intrinsics::ctpop16, intrinsics::ctlz16, intrinsics::cttz16)
+bitwise_impl!(u32, 32, intrinsics::ctpop32, intrinsics::ctlz32, intrinsics::cttz32)
+bitwise_impl!(u64, 64, intrinsics::ctpop64, intrinsics::ctlz64, intrinsics::cttz64)
#[cfg(target_word_size = "32")]
-bitwise_cast_impl!(int, u32, 32, ctpop32, ctlz32, cttz32, intrinsics::bswap32)
+bitwise_cast_impl!(int, u32, 32, intrinsics::ctpop32, intrinsics::ctlz32, intrinsics::cttz32)
#[cfg(target_word_size = "64")]
-bitwise_cast_impl!(int, u64, 64, ctpop64, ctlz64, cttz64, intrinsics::bswap64)
+bitwise_cast_impl!(int, u64, 64, intrinsics::ctpop64, intrinsics::ctlz64, intrinsics::cttz64)
-bitwise_cast_impl!(i8, u8, 8, ctpop8, ctlz8, cttz8, bswap8)
-bitwise_cast_impl!(i16, u16, 16, ctpop16, ctlz16, cttz16, intrinsics::bswap16)
-bitwise_cast_impl!(i32, u32, 32, ctpop32, ctlz32, cttz32, intrinsics::bswap32)
-bitwise_cast_impl!(i64, u64, 64, ctpop64, ctlz64, cttz64, intrinsics::bswap64)
+bitwise_cast_impl!(i8, u8, 8, intrinsics::ctpop8, intrinsics::ctlz8, intrinsics::cttz8)
+bitwise_cast_impl!(i16, u16, 16, intrinsics::ctpop16, intrinsics::ctlz16, intrinsics::cttz16)
+bitwise_cast_impl!(i32, u32, 32, intrinsics::ctpop32, intrinsics::ctlz32, intrinsics::cttz32)
+bitwise_cast_impl!(i64, u64, 64, intrinsics::ctpop64, intrinsics::ctlz64, intrinsics::cttz64)
/// Specifies the available operations common to all of Rust's core numeric primitives.
/// These may not always make sense from a purely mathematical point of view, but