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Diffstat (limited to 'library/core/src/num/mod.rs')
| -rw-r--r-- | library/core/src/num/mod.rs | 5359 |
1 files changed, 5359 insertions, 0 deletions
diff --git a/library/core/src/num/mod.rs b/library/core/src/num/mod.rs new file mode 100644 index 00000000000..048c9c5ddaa --- /dev/null +++ b/library/core/src/num/mod.rs @@ -0,0 +1,5359 @@ +// ignore-tidy-filelength + +//! Numeric traits and functions for the built-in numeric types. + +#![stable(feature = "rust1", since = "1.0.0")] + +use crate::convert::Infallible; +use crate::fmt; +use crate::intrinsics; +use crate::mem; +use crate::ops::{BitOr, BitOrAssign}; +use crate::str::FromStr; + +// Used because the `?` operator is not allowed in a const context. +macro_rules! try_opt { + ($e:expr) => { + match $e { + Some(x) => x, + None => return None, + } + }; +} + +#[allow_internal_unstable(const_likely)] +macro_rules! unlikely { + ($e: expr) => { + intrinsics::unlikely($e) + }; +} + +macro_rules! impl_nonzero_fmt { + ( #[$stability: meta] ( $( $Trait: ident ),+ ) for $Ty: ident ) => { + $( + #[$stability] + impl fmt::$Trait for $Ty { + #[inline] + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.get().fmt(f) + } + } + )+ + } +} + +macro_rules! doc_comment { + ($x:expr, $($tt:tt)*) => { + #[doc = $x] + $($tt)* + }; +} + +macro_rules! nonzero_integers { + ( $( #[$stability: meta] $Ty: ident($Int: ty); )+ ) => { + $( + doc_comment! { + concat!("An integer that is known not to equal zero. + +This enables some memory layout optimization. +For example, `Option<", stringify!($Ty), ">` is the same size as `", stringify!($Int), "`: + +```rust +use std::mem::size_of; +assert_eq!(size_of::<Option<core::num::", stringify!($Ty), ">>(), size_of::<", stringify!($Int), +">()); +```"), + #[$stability] + #[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)] + #[repr(transparent)] + #[rustc_layout_scalar_valid_range_start(1)] + #[rustc_nonnull_optimization_guaranteed] + pub struct $Ty($Int); + } + + impl $Ty { + /// Creates a non-zero without checking the value. + /// + /// # Safety + /// + /// The value must not be zero. + #[$stability] + #[rustc_const_stable(feature = "nonzero", since = "1.34.0")] + #[inline] + pub const unsafe fn new_unchecked(n: $Int) -> Self { + // SAFETY: this is guaranteed to be safe by the caller. + unsafe { Self(n) } + } + + /// Creates a non-zero if the given value is not zero. + #[$stability] + #[rustc_const_stable(feature = "const_nonzero_int_methods", since = "1.47.0")] + #[inline] + pub const fn new(n: $Int) -> Option<Self> { + if n != 0 { + // SAFETY: we just checked that there's no `0` + Some(unsafe { Self(n) }) + } else { + None + } + } + + /// Returns the value as a primitive type. + #[$stability] + #[inline] + #[rustc_const_stable(feature = "nonzero", since = "1.34.0")] + pub const fn get(self) -> $Int { + self.0 + } + + } + + #[stable(feature = "from_nonzero", since = "1.31.0")] + impl From<$Ty> for $Int { + doc_comment! { + concat!( +"Converts a `", stringify!($Ty), "` into an `", stringify!($Int), "`"), + fn from(nonzero: $Ty) -> Self { + nonzero.0 + } + } + } + + #[stable(feature = "nonzero_bitor", since = "1.45.0")] + impl BitOr for $Ty { + type Output = Self; + #[inline] + fn bitor(self, rhs: Self) -> Self::Output { + // Safety: since `self` and `rhs` are both nonzero, the + // result of the bitwise-or will be nonzero. + unsafe { $Ty::new_unchecked(self.get() | rhs.get()) } + } + } + + #[stable(feature = "nonzero_bitor", since = "1.45.0")] + impl BitOr<$Int> for $Ty { + type Output = Self; + #[inline] + fn bitor(self, rhs: $Int) -> Self::Output { + // Safety: since `self` is nonzero, the result of the + // bitwise-or will be nonzero regardless of the value of + // `rhs`. + unsafe { $Ty::new_unchecked(self.get() | rhs) } + } + } + + #[stable(feature = "nonzero_bitor", since = "1.45.0")] + impl BitOr<$Ty> for $Int { + type Output = $Ty; + #[inline] + fn bitor(self, rhs: $Ty) -> Self::Output { + // Safety: since `rhs` is nonzero, the result of the + // bitwise-or will be nonzero regardless of the value of + // `self`. + unsafe { $Ty::new_unchecked(self | rhs.get()) } + } + } + + #[stable(feature = "nonzero_bitor", since = "1.45.0")] + impl BitOrAssign for $Ty { + #[inline] + fn bitor_assign(&mut self, rhs: Self) { + *self = *self | rhs; + } + } + + #[stable(feature = "nonzero_bitor", since = "1.45.0")] + impl BitOrAssign<$Int> for $Ty { + #[inline] + fn bitor_assign(&mut self, rhs: $Int) { + *self = *self | rhs; + } + } + + impl_nonzero_fmt! { + #[$stability] (Debug, Display, Binary, Octal, LowerHex, UpperHex) for $Ty + } + )+ + } +} + +nonzero_integers! { + #[stable(feature = "nonzero", since = "1.28.0")] NonZeroU8(u8); + #[stable(feature = "nonzero", since = "1.28.0")] NonZeroU16(u16); + #[stable(feature = "nonzero", since = "1.28.0")] NonZeroU32(u32); + #[stable(feature = "nonzero", since = "1.28.0")] NonZeroU64(u64); + #[stable(feature = "nonzero", since = "1.28.0")] NonZeroU128(u128); + #[stable(feature = "nonzero", since = "1.28.0")] NonZeroUsize(usize); + #[stable(feature = "signed_nonzero", since = "1.34.0")] NonZeroI8(i8); + #[stable(feature = "signed_nonzero", since = "1.34.0")] NonZeroI16(i16); + #[stable(feature = "signed_nonzero", since = "1.34.0")] NonZeroI32(i32); + #[stable(feature = "signed_nonzero", since = "1.34.0")] NonZeroI64(i64); + #[stable(feature = "signed_nonzero", since = "1.34.0")] NonZeroI128(i128); + #[stable(feature = "signed_nonzero", since = "1.34.0")] NonZeroIsize(isize); +} + +macro_rules! from_str_radix_nzint_impl { + ($($t:ty)*) => {$( + #[stable(feature = "nonzero_parse", since = "1.35.0")] + impl FromStr for $t { + type Err = ParseIntError; + fn from_str(src: &str) -> Result<Self, Self::Err> { + Self::new(from_str_radix(src, 10)?) + .ok_or(ParseIntError { + kind: IntErrorKind::Zero + }) + } + } + )*} +} + +from_str_radix_nzint_impl! { NonZeroU8 NonZeroU16 NonZeroU32 NonZeroU64 NonZeroU128 NonZeroUsize +NonZeroI8 NonZeroI16 NonZeroI32 NonZeroI64 NonZeroI128 NonZeroIsize } + +/// Provides intentionally-wrapped arithmetic on `T`. +/// +/// Operations like `+` on `u32` values are intended to never overflow, +/// and in some debug configurations overflow is detected and results +/// in a panic. While most arithmetic falls into this category, some +/// code explicitly expects and relies upon modular arithmetic (e.g., +/// hashing). +/// +/// Wrapping arithmetic can be achieved either through methods like +/// `wrapping_add`, or through the `Wrapping<T>` type, which says that +/// all standard arithmetic operations on the underlying value are +/// intended to have wrapping semantics. +/// +/// The underlying value can be retrieved through the `.0` index of the +/// `Wrapping` tuple. +/// +/// # Examples +/// +/// ``` +/// use std::num::Wrapping; +/// +/// let zero = Wrapping(0u32); +/// let one = Wrapping(1u32); +/// +/// assert_eq!(u32::MAX, (zero - one).0); +/// ``` +#[stable(feature = "rust1", since = "1.0.0")] +#[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Copy, Default, Hash)] +#[repr(transparent)] +pub struct Wrapping<T>(#[stable(feature = "rust1", since = "1.0.0")] pub T); + +#[stable(feature = "rust1", since = "1.0.0")] +impl<T: fmt::Debug> fmt::Debug for Wrapping<T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.0.fmt(f) + } +} + +#[stable(feature = "wrapping_display", since = "1.10.0")] +impl<T: fmt::Display> fmt::Display for Wrapping<T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.0.fmt(f) + } +} + +#[stable(feature = "wrapping_fmt", since = "1.11.0")] +impl<T: fmt::Binary> fmt::Binary for Wrapping<T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.0.fmt(f) + } +} + +#[stable(feature = "wrapping_fmt", since = "1.11.0")] +impl<T: fmt::Octal> fmt::Octal for Wrapping<T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.0.fmt(f) + } +} + +#[stable(feature = "wrapping_fmt", since = "1.11.0")] +impl<T: fmt::LowerHex> fmt::LowerHex for Wrapping<T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.0.fmt(f) + } +} + +#[stable(feature = "wrapping_fmt", since = "1.11.0")] +impl<T: fmt::UpperHex> fmt::UpperHex for Wrapping<T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.0.fmt(f) + } +} + +// All these modules are technically private and only exposed for coretests: +pub mod bignum; +pub mod dec2flt; +pub mod diy_float; +pub mod flt2dec; + +mod wrapping; + +macro_rules! usize_isize_to_xe_bytes_doc { + () => { + " + +**Note**: This function returns an array of length 2, 4 or 8 bytes +depending on the target pointer size. + +" + }; +} + +macro_rules! usize_isize_from_xe_bytes_doc { + () => { + " + +**Note**: This function takes an array of length 2, 4 or 8 bytes +depending on the target pointer size. + +" + }; +} + +macro_rules! int_impl { + ($SelfT:ty, $ActualT:ident, $UnsignedT:ty, $BITS:expr, $Min:expr, $Max:expr, $Feature:expr, + $EndFeature:expr, $rot:expr, $rot_op:expr, $rot_result:expr, $swap_op:expr, $swapped:expr, + $reversed:expr, $le_bytes:expr, $be_bytes:expr, + $to_xe_bytes_doc:expr, $from_xe_bytes_doc:expr) => { + doc_comment! { + concat!("The smallest value that can be represented by this integer type. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(", stringify!($SelfT), "::MIN, ", stringify!($Min), ");", +$EndFeature, " +```"), + #[stable(feature = "assoc_int_consts", since = "1.43.0")] + pub const MIN: Self = !0 ^ ((!0 as $UnsignedT) >> 1) as Self; + } + + doc_comment! { + concat!("The largest value that can be represented by this integer type. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(", stringify!($SelfT), "::MAX, ", stringify!($Max), ");", +$EndFeature, " +```"), + #[stable(feature = "assoc_int_consts", since = "1.43.0")] + pub const MAX: Self = !Self::MIN; + } + + doc_comment! { + concat!("Converts a string slice in a given base to an integer. + +The string is expected to be an optional `+` or `-` sign followed by digits. +Leading and trailing whitespace represent an error. Digits are a subset of these characters, +depending on `radix`: + + * `0-9` + * `a-z` + * `A-Z` + +# Panics + +This function panics if `radix` is not in the range from 2 to 36. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(", stringify!($SelfT), "::from_str_radix(\"A\", 16), Ok(10));", +$EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + pub fn from_str_radix(src: &str, radix: u32) -> Result<Self, ParseIntError> { + from_str_radix(src, radix) + } + } + + doc_comment! { + concat!("Returns the number of ones in the binary representation of `self`. + +# Examples + +Basic usage: + +``` +", $Feature, "let n = 0b100_0000", stringify!($SelfT), "; + +assert_eq!(n.count_ones(), 1);", +$EndFeature, " +``` +"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")] + #[inline] + pub const fn count_ones(self) -> u32 { (self as $UnsignedT).count_ones() } + } + + doc_comment! { + concat!("Returns the number of zeros in the binary representation of `self`. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(", stringify!($SelfT), "::MAX.count_zeros(), 1);", $EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")] + #[inline] + pub const fn count_zeros(self) -> u32 { + (!self).count_ones() + } + } + + doc_comment! { + concat!("Returns the number of leading zeros in the binary representation of `self`. + +# Examples + +Basic usage: + +``` +", $Feature, "let n = -1", stringify!($SelfT), "; + +assert_eq!(n.leading_zeros(), 0);", +$EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")] + #[inline] + pub const fn leading_zeros(self) -> u32 { + (self as $UnsignedT).leading_zeros() + } + } + + doc_comment! { + concat!("Returns the number of trailing zeros in the binary representation of `self`. + +# Examples + +Basic usage: + +``` +", $Feature, "let n = -4", stringify!($SelfT), "; + +assert_eq!(n.trailing_zeros(), 2);", +$EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")] + #[inline] + pub const fn trailing_zeros(self) -> u32 { + (self as $UnsignedT).trailing_zeros() + } + } + + doc_comment! { + concat!("Returns the number of leading ones in the binary representation of `self`. + +# Examples + +Basic usage: + +``` +", $Feature, "let n = -1", stringify!($SelfT), "; + +assert_eq!(n.leading_ones(), ", stringify!($BITS), ");", +$EndFeature, " +```"), + #[stable(feature = "leading_trailing_ones", since = "1.46.0")] + #[rustc_const_stable(feature = "leading_trailing_ones", since = "1.46.0")] + #[inline] + pub const fn leading_ones(self) -> u32 { + (self as $UnsignedT).leading_ones() + } + } + + doc_comment! { + concat!("Returns the number of trailing ones in the binary representation of `self`. + +# Examples + +Basic usage: + +``` +", $Feature, "let n = 3", stringify!($SelfT), "; + +assert_eq!(n.trailing_ones(), 2);", +$EndFeature, " +```"), + #[stable(feature = "leading_trailing_ones", since = "1.46.0")] + #[rustc_const_stable(feature = "leading_trailing_ones", since = "1.46.0")] + #[inline] + pub const fn trailing_ones(self) -> u32 { + (self as $UnsignedT).trailing_ones() + } + } + + doc_comment! { + concat!("Shifts the bits to the left by a specified amount, `n`, +wrapping the truncated bits to the end of the resulting integer. + +Please note this isn't the same operation as the `<<` shifting operator! + +# Examples + +Basic usage: + +``` +let n = ", $rot_op, stringify!($SelfT), "; +let m = ", $rot_result, "; + +assert_eq!(n.rotate_left(", $rot, "), m); +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn rotate_left(self, n: u32) -> Self { + (self as $UnsignedT).rotate_left(n) as Self + } + } + + doc_comment! { + concat!("Shifts the bits to the right by a specified amount, `n`, +wrapping the truncated bits to the beginning of the resulting +integer. + +Please note this isn't the same operation as the `>>` shifting operator! + +# Examples + +Basic usage: + +``` +let n = ", $rot_result, stringify!($SelfT), "; +let m = ", $rot_op, "; + +assert_eq!(n.rotate_right(", $rot, "), m); +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn rotate_right(self, n: u32) -> Self { + (self as $UnsignedT).rotate_right(n) as Self + } + } + + doc_comment! { + concat!("Reverses the byte order of the integer. + +# Examples + +Basic usage: + +``` +let n = ", $swap_op, stringify!($SelfT), "; + +let m = n.swap_bytes(); + +assert_eq!(m, ", $swapped, "); +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")] + #[inline] + pub const fn swap_bytes(self) -> Self { + (self as $UnsignedT).swap_bytes() as Self + } + } + + doc_comment! { + concat!("Reverses the bit pattern of the integer. + +# Examples + +Basic usage: + +``` +let n = ", $swap_op, stringify!($SelfT), "; +let m = n.reverse_bits(); + +assert_eq!(m, ", $reversed, "); +```"), + #[stable(feature = "reverse_bits", since = "1.37.0")] + #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")] + #[inline] + #[must_use] + pub const fn reverse_bits(self) -> Self { + (self as $UnsignedT).reverse_bits() as Self + } + } + + doc_comment! { + concat!("Converts an integer from big endian to the target's endianness. + +On big endian this is a no-op. On little endian the bytes are swapped. + +# Examples + +Basic usage: + +``` +", $Feature, "let n = 0x1A", stringify!($SelfT), "; + +if cfg!(target_endian = \"big\") { + assert_eq!(", stringify!($SelfT), "::from_be(n), n) +} else { + assert_eq!(", stringify!($SelfT), "::from_be(n), n.swap_bytes()) +}", +$EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_int_conversions", since = "1.32.0")] + #[inline] + pub const fn from_be(x: Self) -> Self { + #[cfg(target_endian = "big")] + { + x + } + #[cfg(not(target_endian = "big"))] + { + x.swap_bytes() + } + } + } + + doc_comment! { + concat!("Converts an integer from little endian to the target's endianness. + +On little endian this is a no-op. On big endian the bytes are swapped. + +# Examples + +Basic usage: + +``` +", $Feature, "let n = 0x1A", stringify!($SelfT), "; + +if cfg!(target_endian = \"little\") { + assert_eq!(", stringify!($SelfT), "::from_le(n), n) +} else { + assert_eq!(", stringify!($SelfT), "::from_le(n), n.swap_bytes()) +}", +$EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_int_conversions", since = "1.32.0")] + #[inline] + pub const fn from_le(x: Self) -> Self { + #[cfg(target_endian = "little")] + { + x + } + #[cfg(not(target_endian = "little"))] + { + x.swap_bytes() + } + } + } + + doc_comment! { + concat!("Converts `self` to big endian from the target's endianness. + +On big endian this is a no-op. On little endian the bytes are swapped. + +# Examples + +Basic usage: + +``` +", $Feature, "let n = 0x1A", stringify!($SelfT), "; + +if cfg!(target_endian = \"big\") { + assert_eq!(n.to_be(), n) +} else { + assert_eq!(n.to_be(), n.swap_bytes()) +}", +$EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_int_conversions", since = "1.32.0")] + #[inline] + pub const fn to_be(self) -> Self { // or not to be? + #[cfg(target_endian = "big")] + { + self + } + #[cfg(not(target_endian = "big"))] + { + self.swap_bytes() + } + } + } + + doc_comment! { + concat!("Converts `self` to little endian from the target's endianness. + +On little endian this is a no-op. On big endian the bytes are swapped. + +# Examples + +Basic usage: + +``` +", $Feature, "let n = 0x1A", stringify!($SelfT), "; + +if cfg!(target_endian = \"little\") { + assert_eq!(n.to_le(), n) +} else { + assert_eq!(n.to_le(), n.swap_bytes()) +}", +$EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_int_conversions", since = "1.32.0")] + #[inline] + pub const fn to_le(self) -> Self { + #[cfg(target_endian = "little")] + { + self + } + #[cfg(not(target_endian = "little"))] + { + self.swap_bytes() + } + } + } + + doc_comment! { + concat!("Checked integer addition. Computes `self + rhs`, returning `None` +if overflow occurred. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!((", stringify!($SelfT), +"::MAX - 2).checked_add(1), Some(", stringify!($SelfT), "::MAX - 1)); +assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add(3), None);", +$EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn checked_add(self, rhs: Self) -> Option<Self> { + let (a, b) = self.overflowing_add(rhs); + if unlikely!(b) {None} else {Some(a)} + } + } + + doc_comment! { + concat!("Unchecked integer addition. Computes `self + rhs`, assuming overflow +cannot occur. This results in undefined behavior when `self + rhs > ", stringify!($SelfT), +"::MAX` or `self + rhs < ", stringify!($SelfT), "::MIN`."), + #[unstable( + feature = "unchecked_math", + reason = "niche optimization path", + issue = "none", + )] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub unsafe fn unchecked_add(self, rhs: Self) -> Self { + // SAFETY: the caller must uphold the safety contract for + // `unchecked_add`. + unsafe { intrinsics::unchecked_add(self, rhs) } + } + } + + doc_comment! { + concat!("Checked integer subtraction. Computes `self - rhs`, returning `None` if +overflow occurred. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!((", stringify!($SelfT), +"::MIN + 2).checked_sub(1), Some(", stringify!($SelfT), "::MIN + 1)); +assert_eq!((", stringify!($SelfT), "::MIN + 2).checked_sub(3), None);", +$EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn checked_sub(self, rhs: Self) -> Option<Self> { + let (a, b) = self.overflowing_sub(rhs); + if unlikely!(b) {None} else {Some(a)} + } + } + + doc_comment! { + concat!("Unchecked integer subtraction. Computes `self - rhs`, assuming overflow +cannot occur. This results in undefined behavior when `self - rhs > ", stringify!($SelfT), +"::MAX` or `self - rhs < ", stringify!($SelfT), "::MIN`."), + #[unstable( + feature = "unchecked_math", + reason = "niche optimization path", + issue = "none", + )] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub unsafe fn unchecked_sub(self, rhs: Self) -> Self { + // SAFETY: the caller must uphold the safety contract for + // `unchecked_sub`. + unsafe { intrinsics::unchecked_sub(self, rhs) } + } + } + + doc_comment! { + concat!("Checked integer multiplication. Computes `self * rhs`, returning `None` if +overflow occurred. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(", stringify!($SelfT), +"::MAX.checked_mul(1), Some(", stringify!($SelfT), "::MAX)); +assert_eq!(", stringify!($SelfT), "::MAX.checked_mul(2), None);", +$EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn checked_mul(self, rhs: Self) -> Option<Self> { + let (a, b) = self.overflowing_mul(rhs); + if unlikely!(b) {None} else {Some(a)} + } + } + + doc_comment! { + concat!("Unchecked integer multiplication. Computes `self * rhs`, assuming overflow +cannot occur. This results in undefined behavior when `self * rhs > ", stringify!($SelfT), +"::MAX` or `self * rhs < ", stringify!($SelfT), "::MIN`."), + #[unstable( + feature = "unchecked_math", + reason = "niche optimization path", + issue = "none", + )] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub unsafe fn unchecked_mul(self, rhs: Self) -> Self { + // SAFETY: the caller must uphold the safety contract for + // `unchecked_mul`. + unsafe { intrinsics::unchecked_mul(self, rhs) } + } + } + + doc_comment! { + concat!("Checked integer division. Computes `self / rhs`, returning `None` if `rhs == 0` +or the division results in overflow. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!((", stringify!($SelfT), +"::MIN + 1).checked_div(-1), Some(", stringify!($Max), ")); +assert_eq!(", stringify!($SelfT), "::MIN.checked_div(-1), None); +assert_eq!((1", stringify!($SelfT), ").checked_div(0), None);", +$EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_unstable(feature = "const_checked_int_methods", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn checked_div(self, rhs: Self) -> Option<Self> { + if unlikely!(rhs == 0 || (self == Self::MIN && rhs == -1)) { + None + } else { + // SAFETY: div by zero and by INT_MIN have been checked above + Some(unsafe { intrinsics::unchecked_div(self, rhs) }) + } + } + } + + doc_comment! { + concat!("Checked Euclidean division. Computes `self.div_euclid(rhs)`, +returning `None` if `rhs == 0` or the division results in overflow. + +# Examples + +Basic usage: + +``` +assert_eq!((", stringify!($SelfT), +"::MIN + 1).checked_div_euclid(-1), Some(", stringify!($Max), ")); +assert_eq!(", stringify!($SelfT), "::MIN.checked_div_euclid(-1), None); +assert_eq!((1", stringify!($SelfT), ").checked_div_euclid(0), None); +```"), + #[stable(feature = "euclidean_division", since = "1.38.0")] + #[rustc_const_unstable(feature = "const_euclidean_int_methods", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn checked_div_euclid(self, rhs: Self) -> Option<Self> { + if unlikely!(rhs == 0 || (self == Self::MIN && rhs == -1)) { + None + } else { + Some(self.div_euclid(rhs)) + } + } + } + + doc_comment! { + concat!("Checked integer remainder. Computes `self % rhs`, returning `None` if +`rhs == 0` or the division results in overflow. + +# Examples + +Basic usage: + +``` +", $Feature, " +assert_eq!(5", stringify!($SelfT), ".checked_rem(2), Some(1)); +assert_eq!(5", stringify!($SelfT), ".checked_rem(0), None); +assert_eq!(", stringify!($SelfT), "::MIN.checked_rem(-1), None);", +$EndFeature, " +```"), + #[stable(feature = "wrapping", since = "1.7.0")] + #[rustc_const_unstable(feature = "const_checked_int_methods", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn checked_rem(self, rhs: Self) -> Option<Self> { + if unlikely!(rhs == 0 || (self == Self::MIN && rhs == -1)) { + None + } else { + // SAFETY: div by zero and by INT_MIN have been checked above + Some(unsafe { intrinsics::unchecked_rem(self, rhs) }) + } + } + } + + doc_comment! { + concat!("Checked Euclidean remainder. Computes `self.rem_euclid(rhs)`, returning `None` +if `rhs == 0` or the division results in overflow. + +# Examples + +Basic usage: + +``` +assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(2), Some(1)); +assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(0), None); +assert_eq!(", stringify!($SelfT), "::MIN.checked_rem_euclid(-1), None); +```"), + #[stable(feature = "euclidean_division", since = "1.38.0")] + #[rustc_const_unstable(feature = "const_euclidean_int_methods", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn checked_rem_euclid(self, rhs: Self) -> Option<Self> { + if unlikely!(rhs == 0 || (self == Self::MIN && rhs == -1)) { + None + } else { + Some(self.rem_euclid(rhs)) + } + } + } + + doc_comment! { + concat!("Checked negation. Computes `-self`, returning `None` if `self == MIN`. + +# Examples + +Basic usage: + +``` +", $Feature, " +assert_eq!(5", stringify!($SelfT), ".checked_neg(), Some(-5)); +assert_eq!(", stringify!($SelfT), "::MIN.checked_neg(), None);", +$EndFeature, " +```"), + #[stable(feature = "wrapping", since = "1.7.0")] + #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")] + #[inline] + pub const fn checked_neg(self) -> Option<Self> { + let (a, b) = self.overflowing_neg(); + if unlikely!(b) {None} else {Some(a)} + } + } + + doc_comment! { + concat!("Checked shift left. Computes `self << rhs`, returning `None` if `rhs` is larger +than or equal to the number of bits in `self`. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(0x1", stringify!($SelfT), ".checked_shl(4), Some(0x10)); +assert_eq!(0x1", stringify!($SelfT), ".checked_shl(129), None);", +$EndFeature, " +```"), + #[stable(feature = "wrapping", since = "1.7.0")] + #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn checked_shl(self, rhs: u32) -> Option<Self> { + let (a, b) = self.overflowing_shl(rhs); + if unlikely!(b) {None} else {Some(a)} + } + } + + doc_comment! { + concat!("Checked shift right. Computes `self >> rhs`, returning `None` if `rhs` is +larger than or equal to the number of bits in `self`. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(0x10", stringify!($SelfT), ".checked_shr(4), Some(0x1)); +assert_eq!(0x10", stringify!($SelfT), ".checked_shr(128), None);", +$EndFeature, " +```"), + #[stable(feature = "wrapping", since = "1.7.0")] + #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn checked_shr(self, rhs: u32) -> Option<Self> { + let (a, b) = self.overflowing_shr(rhs); + if unlikely!(b) {None} else {Some(a)} + } + } + + doc_comment! { + concat!("Checked absolute value. Computes `self.abs()`, returning `None` if +`self == MIN`. + +# Examples + +Basic usage: + +``` +", $Feature, " +assert_eq!((-5", stringify!($SelfT), ").checked_abs(), Some(5)); +assert_eq!(", stringify!($SelfT), "::MIN.checked_abs(), None);", +$EndFeature, " +```"), + #[stable(feature = "no_panic_abs", since = "1.13.0")] + #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")] + #[inline] + pub const fn checked_abs(self) -> Option<Self> { + if self.is_negative() { + self.checked_neg() + } else { + Some(self) + } + } + } + + doc_comment! { + concat!("Checked exponentiation. Computes `self.pow(exp)`, returning `None` if +overflow occurred. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(8", stringify!($SelfT), ".checked_pow(2), Some(64)); +assert_eq!(", stringify!($SelfT), "::MAX.checked_pow(2), None);", +$EndFeature, " +```"), + + #[stable(feature = "no_panic_pow", since = "1.34.0")] + #[rustc_const_unstable(feature = "const_int_pow", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn checked_pow(self, mut exp: u32) -> Option<Self> { + if exp == 0 { + return Some(1); + } + let mut base = self; + let mut acc: Self = 1; + + while exp > 1 { + if (exp & 1) == 1 { + acc = try_opt!(acc.checked_mul(base)); + } + exp /= 2; + base = try_opt!(base.checked_mul(base)); + } + // since exp!=0, finally the exp must be 1. + // Deal with the final bit of the exponent separately, since + // squaring the base afterwards is not necessary and may cause a + // needless overflow. + Some(try_opt!(acc.checked_mul(base))) + } + } + + doc_comment! { + concat!("Saturating integer addition. Computes `self + rhs`, saturating at the numeric +bounds instead of overflowing. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(100", stringify!($SelfT), ".saturating_add(1), 101); +assert_eq!(", stringify!($SelfT), "::MAX.saturating_add(100), ", stringify!($SelfT), +"::MAX); +assert_eq!(", stringify!($SelfT), "::MIN.saturating_add(-1), ", stringify!($SelfT), +"::MIN);", +$EndFeature, " +```"), + + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn saturating_add(self, rhs: Self) -> Self { + intrinsics::saturating_add(self, rhs) + } + } + + doc_comment! { + concat!("Saturating integer subtraction. Computes `self - rhs`, saturating at the +numeric bounds instead of overflowing. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(100", stringify!($SelfT), ".saturating_sub(127), -27); +assert_eq!(", stringify!($SelfT), "::MIN.saturating_sub(100), ", stringify!($SelfT), +"::MIN); +assert_eq!(", stringify!($SelfT), "::MAX.saturating_sub(-1), ", stringify!($SelfT), +"::MAX);", +$EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn saturating_sub(self, rhs: Self) -> Self { + intrinsics::saturating_sub(self, rhs) + } + } + + doc_comment! { + concat!("Saturating integer negation. Computes `-self`, returning `MAX` if `self == MIN` +instead of overflowing. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(100", stringify!($SelfT), ".saturating_neg(), -100); +assert_eq!((-100", stringify!($SelfT), ").saturating_neg(), 100); +assert_eq!(", stringify!($SelfT), "::MIN.saturating_neg(), ", stringify!($SelfT), +"::MAX); +assert_eq!(", stringify!($SelfT), "::MAX.saturating_neg(), ", stringify!($SelfT), +"::MIN + 1);", +$EndFeature, " +```"), + + #[stable(feature = "saturating_neg", since = "1.45.0")] + #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")] + #[inline] + pub const fn saturating_neg(self) -> Self { + intrinsics::saturating_sub(0, self) + } + } + + doc_comment! { + concat!("Saturating absolute value. Computes `self.abs()`, returning `MAX` if `self == +MIN` instead of overflowing. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(100", stringify!($SelfT), ".saturating_abs(), 100); +assert_eq!((-100", stringify!($SelfT), ").saturating_abs(), 100); +assert_eq!(", stringify!($SelfT), "::MIN.saturating_abs(), ", stringify!($SelfT), +"::MAX); +assert_eq!((", stringify!($SelfT), "::MIN + 1).saturating_abs(), ", stringify!($SelfT), +"::MAX);", +$EndFeature, " +```"), + + #[stable(feature = "saturating_neg", since = "1.45.0")] + #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")] + #[inline] + pub const fn saturating_abs(self) -> Self { + if self.is_negative() { + self.saturating_neg() + } else { + self + } + } + } + + doc_comment! { + concat!("Saturating integer multiplication. Computes `self * rhs`, saturating at the +numeric bounds instead of overflowing. + +# Examples + +Basic usage: + +``` +", $Feature, " +assert_eq!(10", stringify!($SelfT), ".saturating_mul(12), 120); +assert_eq!(", stringify!($SelfT), "::MAX.saturating_mul(10), ", stringify!($SelfT), "::MAX); +assert_eq!(", stringify!($SelfT), "::MIN.saturating_mul(10), ", stringify!($SelfT), "::MIN);", +$EndFeature, " +```"), + #[stable(feature = "wrapping", since = "1.7.0")] + #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn saturating_mul(self, rhs: Self) -> Self { + match self.checked_mul(rhs) { + Some(x) => x, + None => if (self < 0) == (rhs < 0) { + Self::MAX + } else { + Self::MIN + } + } + } + } + + doc_comment! { + concat!("Saturating integer exponentiation. Computes `self.pow(exp)`, +saturating at the numeric bounds instead of overflowing. + +# Examples + +Basic usage: + +``` +", $Feature, " +assert_eq!((-4", stringify!($SelfT), ").saturating_pow(3), -64); +assert_eq!(", stringify!($SelfT), "::MIN.saturating_pow(2), ", stringify!($SelfT), "::MAX); +assert_eq!(", stringify!($SelfT), "::MIN.saturating_pow(3), ", stringify!($SelfT), "::MIN);", +$EndFeature, " +```"), + #[stable(feature = "no_panic_pow", since = "1.34.0")] + #[rustc_const_unstable(feature = "const_int_pow", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn saturating_pow(self, exp: u32) -> Self { + match self.checked_pow(exp) { + Some(x) => x, + None if self < 0 && exp % 2 == 1 => Self::MIN, + None => Self::MAX, + } + } + } + + doc_comment! { + concat!("Wrapping (modular) addition. Computes `self + rhs`, wrapping around at the +boundary of the type. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(100", stringify!($SelfT), ".wrapping_add(27), 127); +assert_eq!(", stringify!($SelfT), "::MAX.wrapping_add(2), ", stringify!($SelfT), +"::MIN + 1);", +$EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn wrapping_add(self, rhs: Self) -> Self { + intrinsics::wrapping_add(self, rhs) + } + } + + doc_comment! { + concat!("Wrapping (modular) subtraction. Computes `self - rhs`, wrapping around at the +boundary of the type. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(0", stringify!($SelfT), ".wrapping_sub(127), -127); +assert_eq!((-2", stringify!($SelfT), ").wrapping_sub(", stringify!($SelfT), "::MAX), ", +stringify!($SelfT), "::MAX);", +$EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn wrapping_sub(self, rhs: Self) -> Self { + intrinsics::wrapping_sub(self, rhs) + } + } + + doc_comment! { + concat!("Wrapping (modular) multiplication. Computes `self * rhs`, wrapping around at +the boundary of the type. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(10", stringify!($SelfT), ".wrapping_mul(12), 120); +assert_eq!(11i8.wrapping_mul(12), -124);", +$EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn wrapping_mul(self, rhs: Self) -> Self { + intrinsics::wrapping_mul(self, rhs) + } + } + + doc_comment! { + concat!("Wrapping (modular) division. Computes `self / rhs`, wrapping around at the +boundary of the type. + +The only case where such wrapping can occur is when one divides `MIN / -1` on a signed type (where +`MIN` is the negative minimal value for the type); this is equivalent to `-MIN`, a positive value +that is too large to represent in the type. In such a case, this function returns `MIN` itself. + +# Panics + +This function will panic if `rhs` is 0. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(100", stringify!($SelfT), ".wrapping_div(10), 10); +assert_eq!((-128i8).wrapping_div(-1), -128);", +$EndFeature, " +```"), + #[stable(feature = "num_wrapping", since = "1.2.0")] + #[rustc_const_unstable(feature = "const_wrapping_int_methods", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn wrapping_div(self, rhs: Self) -> Self { + self.overflowing_div(rhs).0 + } + } + + doc_comment! { + concat!("Wrapping Euclidean division. Computes `self.div_euclid(rhs)`, +wrapping around at the boundary of the type. + +Wrapping will only occur in `MIN / -1` on a signed type (where `MIN` is the negative minimal value +for the type). This is equivalent to `-MIN`, a positive value that is too large to represent in the +type. In this case, this method returns `MIN` itself. + +# Panics + +This function will panic if `rhs` is 0. + +# Examples + +Basic usage: + +``` +assert_eq!(100", stringify!($SelfT), ".wrapping_div_euclid(10), 10); +assert_eq!((-128i8).wrapping_div_euclid(-1), -128); +```"), + #[stable(feature = "euclidean_division", since = "1.38.0")] + #[rustc_const_unstable(feature = "const_euclidean_int_methods", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn wrapping_div_euclid(self, rhs: Self) -> Self { + self.overflowing_div_euclid(rhs).0 + } + } + + doc_comment! { + concat!("Wrapping (modular) remainder. Computes `self % rhs`, wrapping around at the +boundary of the type. + +Such wrap-around never actually occurs mathematically; implementation artifacts make `x % y` +invalid for `MIN / -1` on a signed type (where `MIN` is the negative minimal value). In such a case, +this function returns `0`. + +# Panics + +This function will panic if `rhs` is 0. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(100", stringify!($SelfT), ".wrapping_rem(10), 0); +assert_eq!((-128i8).wrapping_rem(-1), 0);", +$EndFeature, " +```"), + #[stable(feature = "num_wrapping", since = "1.2.0")] + #[rustc_const_unstable(feature = "const_wrapping_int_methods", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn wrapping_rem(self, rhs: Self) -> Self { + self.overflowing_rem(rhs).0 + } + } + + doc_comment! { + concat!("Wrapping Euclidean remainder. Computes `self.rem_euclid(rhs)`, wrapping around +at the boundary of the type. + +Wrapping will only occur in `MIN % -1` on a signed type (where `MIN` is the negative minimal value +for the type). In this case, this method returns 0. + +# Panics + +This function will panic if `rhs` is 0. + +# Examples + +Basic usage: + +``` +assert_eq!(100", stringify!($SelfT), ".wrapping_rem_euclid(10), 0); +assert_eq!((-128i8).wrapping_rem_euclid(-1), 0); +```"), + #[stable(feature = "euclidean_division", since = "1.38.0")] + #[rustc_const_unstable(feature = "const_euclidean_int_methods", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn wrapping_rem_euclid(self, rhs: Self) -> Self { + self.overflowing_rem_euclid(rhs).0 + } + } + + doc_comment! { + concat!("Wrapping (modular) negation. Computes `-self`, wrapping around at the boundary +of the type. + +The only case where such wrapping can occur is when one negates `MIN` on a signed type (where `MIN` +is the negative minimal value for the type); this is a positive value that is too large to represent +in the type. In such a case, this function returns `MIN` itself. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(100", stringify!($SelfT), ".wrapping_neg(), -100); +assert_eq!(", stringify!($SelfT), "::MIN.wrapping_neg(), ", stringify!($SelfT), +"::MIN);", +$EndFeature, " +```"), + #[stable(feature = "num_wrapping", since = "1.2.0")] + #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")] + #[inline] + pub const fn wrapping_neg(self) -> Self { + self.overflowing_neg().0 + } + } + + doc_comment! { + concat!("Panic-free bitwise shift-left; yields `self << mask(rhs)`, where `mask` removes +any high-order bits of `rhs` that would cause the shift to exceed the bitwidth of the type. + +Note that this is *not* the same as a rotate-left; the RHS of a wrapping shift-left is restricted to +the range of the type, rather than the bits shifted out of the LHS being returned to the other end. +The primitive integer types all implement a `[`rotate_left`](#method.rotate_left) function, +which may be what you want instead. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!((-1", stringify!($SelfT), ").wrapping_shl(7), -128); +assert_eq!((-1", stringify!($SelfT), ").wrapping_shl(128), -1);", +$EndFeature, " +```"), + #[stable(feature = "num_wrapping", since = "1.2.0")] + #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn wrapping_shl(self, rhs: u32) -> Self { + // SAFETY: the masking by the bitsize of the type ensures that we do not shift + // out of bounds + unsafe { + intrinsics::unchecked_shl(self, (rhs & ($BITS - 1)) as $SelfT) + } + } + } + + doc_comment! { + concat!("Panic-free bitwise shift-right; yields `self >> mask(rhs)`, where `mask` +removes any high-order bits of `rhs` that would cause the shift to exceed the bitwidth of the type. + +Note that this is *not* the same as a rotate-right; the RHS of a wrapping shift-right is restricted +to the range of the type, rather than the bits shifted out of the LHS being returned to the other +end. The primitive integer types all implement a [`rotate_right`](#method.rotate_right) function, +which may be what you want instead. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!((-128", stringify!($SelfT), ").wrapping_shr(7), -1); +assert_eq!((-128i16).wrapping_shr(64), -128);", +$EndFeature, " +```"), + #[stable(feature = "num_wrapping", since = "1.2.0")] + #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn wrapping_shr(self, rhs: u32) -> Self { + // SAFETY: the masking by the bitsize of the type ensures that we do not shift + // out of bounds + unsafe { + intrinsics::unchecked_shr(self, (rhs & ($BITS - 1)) as $SelfT) + } + } + } + + doc_comment! { + concat!("Wrapping (modular) absolute value. Computes `self.abs()`, wrapping around at +the boundary of the type. + +The only case where such wrapping can occur is when one takes the absolute value of the negative +minimal value for the type this is a positive value that is too large to represent in the type. In +such a case, this function returns `MIN` itself. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(100", stringify!($SelfT), ".wrapping_abs(), 100); +assert_eq!((-100", stringify!($SelfT), ").wrapping_abs(), 100); +assert_eq!(", stringify!($SelfT), "::MIN.wrapping_abs(), ", stringify!($SelfT), +"::MIN); +assert_eq!((-128i8).wrapping_abs() as u8, 128);", +$EndFeature, " +```"), + #[stable(feature = "no_panic_abs", since = "1.13.0")] + #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")] + #[allow(unused_attributes)] + #[inline] + pub const fn wrapping_abs(self) -> Self { + if self.is_negative() { + self.wrapping_neg() + } else { + self + } + } + } + + doc_comment! { + concat!("Wrapping (modular) exponentiation. Computes `self.pow(exp)`, +wrapping around at the boundary of the type. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(3", stringify!($SelfT), ".wrapping_pow(4), 81); +assert_eq!(3i8.wrapping_pow(5), -13); +assert_eq!(3i8.wrapping_pow(6), -39);", +$EndFeature, " +```"), + #[stable(feature = "no_panic_pow", since = "1.34.0")] + #[rustc_const_unstable(feature = "const_int_pow", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn wrapping_pow(self, mut exp: u32) -> Self { + if exp == 0 { + return 1; + } + let mut base = self; + let mut acc: Self = 1; + + while exp > 1 { + if (exp & 1) == 1 { + acc = acc.wrapping_mul(base); + } + exp /= 2; + base = base.wrapping_mul(base); + } + + // since exp!=0, finally the exp must be 1. + // Deal with the final bit of the exponent separately, since + // squaring the base afterwards is not necessary and may cause a + // needless overflow. + acc.wrapping_mul(base) + } + } + + doc_comment! { + concat!("Calculates `self` + `rhs` + +Returns a tuple of the addition along with a boolean indicating whether an arithmetic overflow would +occur. If an overflow would have occurred then the wrapped value is returned. + +# Examples + +Basic usage: + +``` +", $Feature, " +assert_eq!(5", stringify!($SelfT), ".overflowing_add(2), (7, false)); +assert_eq!(", stringify!($SelfT), "::MAX.overflowing_add(1), (", stringify!($SelfT), +"::MIN, true));", $EndFeature, " +```"), + #[stable(feature = "wrapping", since = "1.7.0")] + #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn overflowing_add(self, rhs: Self) -> (Self, bool) { + let (a, b) = intrinsics::add_with_overflow(self as $ActualT, rhs as $ActualT); + (a as Self, b) + } + } + + doc_comment! { + concat!("Calculates `self` - `rhs` + +Returns a tuple of the subtraction along with a boolean indicating whether an arithmetic overflow +would occur. If an overflow would have occurred then the wrapped value is returned. + +# Examples + +Basic usage: + +``` +", $Feature, " +assert_eq!(5", stringify!($SelfT), ".overflowing_sub(2), (3, false)); +assert_eq!(", stringify!($SelfT), "::MIN.overflowing_sub(1), (", stringify!($SelfT), +"::MAX, true));", $EndFeature, " +```"), + #[stable(feature = "wrapping", since = "1.7.0")] + #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn overflowing_sub(self, rhs: Self) -> (Self, bool) { + let (a, b) = intrinsics::sub_with_overflow(self as $ActualT, rhs as $ActualT); + (a as Self, b) + } + } + + doc_comment! { + concat!("Calculates the multiplication of `self` and `rhs`. + +Returns a tuple of the multiplication along with a boolean indicating whether an arithmetic overflow +would occur. If an overflow would have occurred then the wrapped value is returned. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(5", stringify!($SelfT), ".overflowing_mul(2), (10, false)); +assert_eq!(1_000_000_000i32.overflowing_mul(10), (1410065408, true));", +$EndFeature, " +```"), + #[stable(feature = "wrapping", since = "1.7.0")] + #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn overflowing_mul(self, rhs: Self) -> (Self, bool) { + let (a, b) = intrinsics::mul_with_overflow(self as $ActualT, rhs as $ActualT); + (a as Self, b) + } + } + + doc_comment! { + concat!("Calculates the divisor when `self` is divided by `rhs`. + +Returns a tuple of the divisor along with a boolean indicating whether an arithmetic overflow would +occur. If an overflow would occur then self is returned. + +# Panics + +This function will panic if `rhs` is 0. + +# Examples + +Basic usage: + +``` +", $Feature, " +assert_eq!(5", stringify!($SelfT), ".overflowing_div(2), (2, false)); +assert_eq!(", stringify!($SelfT), "::MIN.overflowing_div(-1), (", stringify!($SelfT), +"::MIN, true));", +$EndFeature, " +```"), + #[inline] + #[stable(feature = "wrapping", since = "1.7.0")] + #[rustc_const_unstable(feature = "const_overflowing_int_methods", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + pub const fn overflowing_div(self, rhs: Self) -> (Self, bool) { + if unlikely!(self == Self::MIN && rhs == -1) { + (self, true) + } else { + (self / rhs, false) + } + } + } + + doc_comment! { + concat!("Calculates the quotient of Euclidean division `self.div_euclid(rhs)`. + +Returns a tuple of the divisor along with a boolean indicating whether an arithmetic overflow would +occur. If an overflow would occur then `self` is returned. + +# Panics + +This function will panic if `rhs` is 0. + +# Examples + +Basic usage: + +``` +assert_eq!(5", stringify!($SelfT), ".overflowing_div_euclid(2), (2, false)); +assert_eq!(", stringify!($SelfT), "::MIN.overflowing_div_euclid(-1), (", stringify!($SelfT), +"::MIN, true)); +```"), + #[inline] + #[stable(feature = "euclidean_division", since = "1.38.0")] + #[rustc_const_unstable(feature = "const_euclidean_int_methods", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + pub const fn overflowing_div_euclid(self, rhs: Self) -> (Self, bool) { + if unlikely!(self == Self::MIN && rhs == -1) { + (self, true) + } else { + (self.div_euclid(rhs), false) + } + } + } + + doc_comment! { + concat!("Calculates the remainder when `self` is divided by `rhs`. + +Returns a tuple of the remainder after dividing along with a boolean indicating whether an +arithmetic overflow would occur. If an overflow would occur then 0 is returned. + +# Panics + +This function will panic if `rhs` is 0. + +# Examples + +Basic usage: + +``` +", $Feature, " +assert_eq!(5", stringify!($SelfT), ".overflowing_rem(2), (1, false)); +assert_eq!(", stringify!($SelfT), "::MIN.overflowing_rem(-1), (0, true));", +$EndFeature, " +```"), + #[inline] + #[stable(feature = "wrapping", since = "1.7.0")] + #[rustc_const_unstable(feature = "const_overflowing_int_methods", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + pub const fn overflowing_rem(self, rhs: Self) -> (Self, bool) { + if unlikely!(self == Self::MIN && rhs == -1) { + (0, true) + } else { + (self % rhs, false) + } + } + } + + + doc_comment! { + concat!("Overflowing Euclidean remainder. Calculates `self.rem_euclid(rhs)`. + +Returns a tuple of the remainder after dividing along with a boolean indicating whether an +arithmetic overflow would occur. If an overflow would occur then 0 is returned. + +# Panics + +This function will panic if `rhs` is 0. + +# Examples + +Basic usage: + +``` +assert_eq!(5", stringify!($SelfT), ".overflowing_rem_euclid(2), (1, false)); +assert_eq!(", stringify!($SelfT), "::MIN.overflowing_rem_euclid(-1), (0, true)); +```"), + #[stable(feature = "euclidean_division", since = "1.38.0")] + #[rustc_const_unstable(feature = "const_euclidean_int_methods", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn overflowing_rem_euclid(self, rhs: Self) -> (Self, bool) { + if unlikely!(self == Self::MIN && rhs == -1) { + (0, true) + } else { + (self.rem_euclid(rhs), false) + } + } + } + + + doc_comment! { + concat!("Negates self, overflowing if this is equal to the minimum value. + +Returns a tuple of the negated version of self along with a boolean indicating whether an overflow +happened. If `self` is the minimum value (e.g., `i32::MIN` for values of type `i32`), then the +minimum value will be returned again and `true` will be returned for an overflow happening. + +# Examples + +Basic usage: + +``` +assert_eq!(2", stringify!($SelfT), ".overflowing_neg(), (-2, false)); +assert_eq!(", stringify!($SelfT), "::MIN.overflowing_neg(), (", stringify!($SelfT), +"::MIN, true));", $EndFeature, " +```"), + #[inline] + #[stable(feature = "wrapping", since = "1.7.0")] + #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")] + #[allow(unused_attributes)] + pub const fn overflowing_neg(self) -> (Self, bool) { + if unlikely!(self == Self::MIN) { + (Self::MIN, true) + } else { + (-self, false) + } + } + } + + doc_comment! { + concat!("Shifts self left by `rhs` bits. + +Returns a tuple of the shifted version of self along with a boolean indicating whether the shift +value was larger than or equal to the number of bits. If the shift value is too large, then value is +masked (N-1) where N is the number of bits, and this value is then used to perform the shift. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(0x1", stringify!($SelfT),".overflowing_shl(4), (0x10, false)); +assert_eq!(0x1i32.overflowing_shl(36), (0x10, true));", +$EndFeature, " +```"), + #[stable(feature = "wrapping", since = "1.7.0")] + #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn overflowing_shl(self, rhs: u32) -> (Self, bool) { + (self.wrapping_shl(rhs), (rhs > ($BITS - 1))) + } + } + + doc_comment! { + concat!("Shifts self right by `rhs` bits. + +Returns a tuple of the shifted version of self along with a boolean indicating whether the shift +value was larger than or equal to the number of bits. If the shift value is too large, then value is +masked (N-1) where N is the number of bits, and this value is then used to perform the shift. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(0x10", stringify!($SelfT), ".overflowing_shr(4), (0x1, false)); +assert_eq!(0x10i32.overflowing_shr(36), (0x1, true));", +$EndFeature, " +```"), + #[stable(feature = "wrapping", since = "1.7.0")] + #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn overflowing_shr(self, rhs: u32) -> (Self, bool) { + (self.wrapping_shr(rhs), (rhs > ($BITS - 1))) + } + } + + doc_comment! { + concat!("Computes the absolute value of `self`. + +Returns a tuple of the absolute version of self along with a boolean indicating whether an overflow +happened. If self is the minimum value (e.g., ", stringify!($SelfT), "::MIN for values of type + ", stringify!($SelfT), "), then the minimum value will be returned again and true will be returned +for an overflow happening. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(10", stringify!($SelfT), ".overflowing_abs(), (10, false)); +assert_eq!((-10", stringify!($SelfT), ").overflowing_abs(), (10, false)); +assert_eq!((", stringify!($SelfT), "::MIN).overflowing_abs(), (", stringify!($SelfT), +"::MIN, true));", +$EndFeature, " +```"), + #[stable(feature = "no_panic_abs", since = "1.13.0")] + #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")] + #[inline] + pub const fn overflowing_abs(self) -> (Self, bool) { + (self.wrapping_abs(), self == Self::MIN) + } + } + + doc_comment! { + concat!("Raises self to the power of `exp`, using exponentiation by squaring. + +Returns a tuple of the exponentiation along with a bool indicating +whether an overflow happened. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(3", stringify!($SelfT), ".overflowing_pow(4), (81, false)); +assert_eq!(3i8.overflowing_pow(5), (-13, true));", +$EndFeature, " +```"), + #[stable(feature = "no_panic_pow", since = "1.34.0")] + #[rustc_const_unstable(feature = "const_int_pow", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn overflowing_pow(self, mut exp: u32) -> (Self, bool) { + if exp == 0 { + return (1,false); + } + let mut base = self; + let mut acc: Self = 1; + let mut overflown = false; + // Scratch space for storing results of overflowing_mul. + let mut r; + + while exp > 1 { + if (exp & 1) == 1 { + r = acc.overflowing_mul(base); + acc = r.0; + overflown |= r.1; + } + exp /= 2; + r = base.overflowing_mul(base); + base = r.0; + overflown |= r.1; + } + + // since exp!=0, finally the exp must be 1. + // Deal with the final bit of the exponent separately, since + // squaring the base afterwards is not necessary and may cause a + // needless overflow. + r = acc.overflowing_mul(base); + r.1 |= overflown; + r + } + } + + doc_comment! { + concat!("Raises self to the power of `exp`, using exponentiation by squaring. + +# Examples + +Basic usage: + +``` +", $Feature, "let x: ", stringify!($SelfT), " = 2; // or any other integer type + +assert_eq!(x.pow(5), 32);", +$EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_unstable(feature = "const_int_pow", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + #[rustc_inherit_overflow_checks] + pub const fn pow(self, mut exp: u32) -> Self { + if exp == 0 { + return 1; + } + let mut base = self; + let mut acc = 1; + + while exp > 1 { + if (exp & 1) == 1 { + acc = acc * base; + } + exp /= 2; + base = base * base; + } + + // since exp!=0, finally the exp must be 1. + // Deal with the final bit of the exponent separately, since + // squaring the base afterwards is not necessary and may cause a + // needless overflow. + acc * base + } + } + + doc_comment! { + concat!("Calculates the quotient of Euclidean division of `self` by `rhs`. + +This computes the integer `n` such that `self = n * rhs + self.rem_euclid(rhs)`, +with `0 <= self.rem_euclid(rhs) < rhs`. + +In other words, the result is `self / rhs` rounded to the integer `n` +such that `self >= n * rhs`. +If `self > 0`, this is equal to round towards zero (the default in Rust); +if `self < 0`, this is equal to round towards +/- infinity. + +# Panics + +This function will panic if `rhs` is 0 or the division results in overflow. + +# Examples + +Basic usage: + +``` +let a: ", stringify!($SelfT), " = 7; // or any other integer type +let b = 4; + +assert_eq!(a.div_euclid(b), 1); // 7 >= 4 * 1 +assert_eq!(a.div_euclid(-b), -1); // 7 >= -4 * -1 +assert_eq!((-a).div_euclid(b), -2); // -7 >= 4 * -2 +assert_eq!((-a).div_euclid(-b), 2); // -7 >= -4 * 2 +```"), + #[stable(feature = "euclidean_division", since = "1.38.0")] + #[rustc_const_unstable(feature = "const_euclidean_int_methods", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + #[rustc_inherit_overflow_checks] + pub const fn div_euclid(self, rhs: Self) -> Self { + let q = self / rhs; + if self % rhs < 0 { + return if rhs > 0 { q - 1 } else { q + 1 } + } + q + } + } + + + doc_comment! { + concat!("Calculates the least nonnegative remainder of `self (mod rhs)`. + +This is done as if by the Euclidean division algorithm -- given +`r = self.rem_euclid(rhs)`, `self = rhs * self.div_euclid(rhs) + r`, and +`0 <= r < abs(rhs)`. + +# Panics + +This function will panic if `rhs` is 0 or the division results in overflow. + +# Examples + +Basic usage: + +``` +let a: ", stringify!($SelfT), " = 7; // or any other integer type +let b = 4; + +assert_eq!(a.rem_euclid(b), 3); +assert_eq!((-a).rem_euclid(b), 1); +assert_eq!(a.rem_euclid(-b), 3); +assert_eq!((-a).rem_euclid(-b), 1); +```"), + #[stable(feature = "euclidean_division", since = "1.38.0")] + #[rustc_const_unstable(feature = "const_euclidean_int_methods", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + #[rustc_inherit_overflow_checks] + pub const fn rem_euclid(self, rhs: Self) -> Self { + let r = self % rhs; + if r < 0 { + if rhs < 0 { + r - rhs + } else { + r + rhs + } + } else { + r + } + } + } + + doc_comment! { + concat!("Computes the absolute value of `self`. + +# Overflow behavior + +The absolute value of `", stringify!($SelfT), "::MIN` cannot be represented as an +`", stringify!($SelfT), "`, and attempting to calculate it will cause an overflow. This means that +code in debug mode will trigger a panic on this case and optimized code will return `", +stringify!($SelfT), "::MIN` without a panic. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(10", stringify!($SelfT), ".abs(), 10); +assert_eq!((-10", stringify!($SelfT), ").abs(), 10);", +$EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")] + #[allow(unused_attributes)] + #[inline] + #[rustc_inherit_overflow_checks] + pub const fn abs(self) -> Self { + // Note that the #[inline] above means that the overflow + // semantics of the subtraction depend on the crate we're being + // inlined into. + if self.is_negative() { + -self + } else { + self + } + } + } + + doc_comment! { + concat!("Returns a number representing sign of `self`. + + - `0` if the number is zero + - `1` if the number is positive + - `-1` if the number is negative + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(10", stringify!($SelfT), ".signum(), 1); +assert_eq!(0", stringify!($SelfT), ".signum(), 0); +assert_eq!((-10", stringify!($SelfT), ").signum(), -1);", +$EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_int_sign", since = "1.47.0")] + #[inline] + pub const fn signum(self) -> Self { + match self { + n if n > 0 => 1, + 0 => 0, + _ => -1, + } + } + } + + doc_comment! { + concat!("Returns `true` if `self` is positive and `false` if the number is zero or +negative. + +# Examples + +Basic usage: + +``` +", $Feature, "assert!(10", stringify!($SelfT), ".is_positive()); +assert!(!(-10", stringify!($SelfT), ").is_positive());", +$EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")] + #[inline] + pub const fn is_positive(self) -> bool { self > 0 } + } + + doc_comment! { + concat!("Returns `true` if `self` is negative and `false` if the number is zero or +positive. + +# Examples + +Basic usage: + +``` +", $Feature, "assert!((-10", stringify!($SelfT), ").is_negative()); +assert!(!10", stringify!($SelfT), ".is_negative());", +$EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")] + #[inline] + pub const fn is_negative(self) -> bool { self < 0 } + } + + doc_comment! { + concat!("Return the memory representation of this integer as a byte array in +big-endian (network) byte order. +", +$to_xe_bytes_doc, +" +# Examples + +``` +let bytes = ", $swap_op, stringify!($SelfT), ".to_be_bytes(); +assert_eq!(bytes, ", $be_bytes, "); +```"), + #[stable(feature = "int_to_from_bytes", since = "1.32.0")] + #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")] + #[inline] + pub const fn to_be_bytes(self) -> [u8; mem::size_of::<Self>()] { + self.to_be().to_ne_bytes() + } + } + +doc_comment! { + concat!("Return the memory representation of this integer as a byte array in +little-endian byte order. +", +$to_xe_bytes_doc, +" +# Examples + +``` +let bytes = ", $swap_op, stringify!($SelfT), ".to_le_bytes(); +assert_eq!(bytes, ", $le_bytes, "); +```"), + #[stable(feature = "int_to_from_bytes", since = "1.32.0")] + #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")] + #[inline] + pub const fn to_le_bytes(self) -> [u8; mem::size_of::<Self>()] { + self.to_le().to_ne_bytes() + } + } + + doc_comment! { + concat!(" +Return the memory representation of this integer as a byte array in +native byte order. + +As the target platform's native endianness is used, portable code +should use [`to_be_bytes`] or [`to_le_bytes`], as appropriate, +instead. +", +$to_xe_bytes_doc, +" +[`to_be_bytes`]: #method.to_be_bytes +[`to_le_bytes`]: #method.to_le_bytes + +# Examples + +``` +let bytes = ", $swap_op, stringify!($SelfT), ".to_ne_bytes(); +assert_eq!( + bytes, + if cfg!(target_endian = \"big\") { + ", $be_bytes, " + } else { + ", $le_bytes, " + } +); +```"), + #[stable(feature = "int_to_from_bytes", since = "1.32.0")] + #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")] + // SAFETY: const sound because integers are plain old datatypes so we can always + // transmute them to arrays of bytes + #[allow_internal_unstable(const_fn_union)] + #[inline] + pub const fn to_ne_bytes(self) -> [u8; mem::size_of::<Self>()] { + #[repr(C)] + union Bytes { + val: $SelfT, + bytes: [u8; mem::size_of::<$SelfT>()], + } + // SAFETY: integers are plain old datatypes so we can always transmute them to + // arrays of bytes + unsafe { Bytes { val: self }.bytes } + } + } + +doc_comment! { + concat!("Create an integer value from its representation as a byte array in +big endian. +", +$from_xe_bytes_doc, +" +# Examples + +``` +let value = ", stringify!($SelfT), "::from_be_bytes(", $be_bytes, "); +assert_eq!(value, ", $swap_op, "); +``` + +When starting from a slice rather than an array, fallible conversion APIs can be used: + +``` +use std::convert::TryInto; + +fn read_be_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " { + let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">()); + *input = rest; + ", stringify!($SelfT), "::from_be_bytes(int_bytes.try_into().unwrap()) +} +```"), + #[stable(feature = "int_to_from_bytes", since = "1.32.0")] + #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")] + #[inline] + pub const fn from_be_bytes(bytes: [u8; mem::size_of::<Self>()]) -> Self { + Self::from_be(Self::from_ne_bytes(bytes)) + } + } + +doc_comment! { + concat!(" +Create an integer value from its representation as a byte array in +little endian. +", +$from_xe_bytes_doc, +" +# Examples + +``` +let value = ", stringify!($SelfT), "::from_le_bytes(", $le_bytes, "); +assert_eq!(value, ", $swap_op, "); +``` + +When starting from a slice rather than an array, fallible conversion APIs can be used: + +``` +use std::convert::TryInto; + +fn read_le_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " { + let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">()); + *input = rest; + ", stringify!($SelfT), "::from_le_bytes(int_bytes.try_into().unwrap()) +} +```"), + #[stable(feature = "int_to_from_bytes", since = "1.32.0")] + #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")] + #[inline] + pub const fn from_le_bytes(bytes: [u8; mem::size_of::<Self>()]) -> Self { + Self::from_le(Self::from_ne_bytes(bytes)) + } + } + + doc_comment! { + concat!("Create an integer value from its memory representation as a byte +array in native endianness. + +As the target platform's native endianness is used, portable code +likely wants to use [`from_be_bytes`] or [`from_le_bytes`], as +appropriate instead. + +[`from_be_bytes`]: #method.from_be_bytes +[`from_le_bytes`]: #method.from_le_bytes +", +$from_xe_bytes_doc, +" +# Examples + +``` +let value = ", stringify!($SelfT), "::from_ne_bytes(if cfg!(target_endian = \"big\") { + ", $be_bytes, " +} else { + ", $le_bytes, " +}); +assert_eq!(value, ", $swap_op, "); +``` + +When starting from a slice rather than an array, fallible conversion APIs can be used: + +``` +use std::convert::TryInto; + +fn read_ne_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " { + let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">()); + *input = rest; + ", stringify!($SelfT), "::from_ne_bytes(int_bytes.try_into().unwrap()) +} +```"), + #[stable(feature = "int_to_from_bytes", since = "1.32.0")] + #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")] + // SAFETY: const sound because integers are plain old datatypes so we can always + // transmute to them + #[allow_internal_unstable(const_fn_union)] + #[inline] + pub const fn from_ne_bytes(bytes: [u8; mem::size_of::<Self>()]) -> Self { + #[repr(C)] + union Bytes { + val: $SelfT, + bytes: [u8; mem::size_of::<$SelfT>()], + } + // SAFETY: integers are plain old datatypes so we can always transmute to them + unsafe { Bytes { bytes }.val } + } + } + + doc_comment! { + concat!("**This method is soft-deprecated.** + +Although using it won’t cause compilation warning, +new code should use [`", stringify!($SelfT), "::MIN", "`](#associatedconstant.MIN) instead. + +Returns the smallest value that can be represented by this integer type."), + #[stable(feature = "rust1", since = "1.0.0")] + #[inline(always)] + #[rustc_promotable] + #[rustc_const_stable(feature = "const_min_value", since = "1.32.0")] + pub const fn min_value() -> Self { + Self::MIN + } + } + + doc_comment! { + concat!("**This method is soft-deprecated.** + +Although using it won’t cause compilation warning, +new code should use [`", stringify!($SelfT), "::MAX", "`](#associatedconstant.MAX) instead. + +Returns the largest value that can be represented by this integer type."), + #[stable(feature = "rust1", since = "1.0.0")] + #[inline(always)] + #[rustc_promotable] + #[rustc_const_stable(feature = "const_max_value", since = "1.32.0")] + pub const fn max_value() -> Self { + Self::MAX + } + } + } +} + +#[lang = "i8"] +impl i8 { + int_impl! { i8, i8, u8, 8, -128, 127, "", "", 2, "-0x7e", "0xa", "0x12", "0x12", "0x48", + "[0x12]", "[0x12]", "", "" } +} + +#[lang = "i16"] +impl i16 { + int_impl! { i16, i16, u16, 16, -32768, 32767, "", "", 4, "-0x5ffd", "0x3a", "0x1234", "0x3412", + "0x2c48", "[0x34, 0x12]", "[0x12, 0x34]", "", "" } +} + +#[lang = "i32"] +impl i32 { + int_impl! { i32, i32, u32, 32, -2147483648, 2147483647, "", "", 8, "0x10000b3", "0xb301", + "0x12345678", "0x78563412", "0x1e6a2c48", "[0x78, 0x56, 0x34, 0x12]", + "[0x12, 0x34, 0x56, 0x78]", "", "" } +} + +#[lang = "i64"] +impl i64 { + int_impl! { i64, i64, u64, 64, -9223372036854775808, 9223372036854775807, "", "", 12, + "0xaa00000000006e1", "0x6e10aa", "0x1234567890123456", "0x5634129078563412", + "0x6a2c48091e6a2c48", "[0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]", + "[0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56]", "", "" } +} + +#[lang = "i128"] +impl i128 { + int_impl! { i128, i128, u128, 128, -170141183460469231731687303715884105728, + 170141183460469231731687303715884105727, "", "", 16, + "0x13f40000000000000000000000004f76", "0x4f7613f4", "0x12345678901234567890123456789012", + "0x12907856341290785634129078563412", "0x48091e6a2c48091e6a2c48091e6a2c48", + "[0x12, 0x90, 0x78, 0x56, 0x34, 0x12, 0x90, 0x78, \ + 0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]", + "[0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56, \ + 0x78, 0x90, 0x12, 0x34, 0x56, 0x78, 0x90, 0x12]", "", "" } +} + +#[cfg(target_pointer_width = "16")] +#[lang = "isize"] +impl isize { + int_impl! { isize, i16, u16, 16, -32768, 32767, "", "", 4, "-0x5ffd", "0x3a", "0x1234", + "0x3412", "0x2c48", "[0x34, 0x12]", "[0x12, 0x34]", + usize_isize_to_xe_bytes_doc!(), usize_isize_from_xe_bytes_doc!() } +} + +#[cfg(target_pointer_width = "32")] +#[lang = "isize"] +impl isize { + int_impl! { isize, i32, u32, 32, -2147483648, 2147483647, "", "", 8, "0x10000b3", "0xb301", + "0x12345678", "0x78563412", "0x1e6a2c48", "[0x78, 0x56, 0x34, 0x12]", + "[0x12, 0x34, 0x56, 0x78]", + usize_isize_to_xe_bytes_doc!(), usize_isize_from_xe_bytes_doc!() } +} + +#[cfg(target_pointer_width = "64")] +#[lang = "isize"] +impl isize { + int_impl! { isize, i64, u64, 64, -9223372036854775808, 9223372036854775807, "", "", + 12, "0xaa00000000006e1", "0x6e10aa", "0x1234567890123456", "0x5634129078563412", + "0x6a2c48091e6a2c48", "[0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]", + "[0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56]", + usize_isize_to_xe_bytes_doc!(), usize_isize_from_xe_bytes_doc!() } +} + +macro_rules! uint_impl { + ($SelfT:ty, $ActualT:ty, $BITS:expr, $MaxV:expr, $Feature:expr, $EndFeature:expr, + $rot:expr, $rot_op:expr, $rot_result:expr, $swap_op:expr, $swapped:expr, + $reversed:expr, $le_bytes:expr, $be_bytes:expr, + $to_xe_bytes_doc:expr, $from_xe_bytes_doc:expr) => { + doc_comment! { + concat!("The smallest value that can be represented by this integer type. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(", stringify!($SelfT), "::MIN, 0);", $EndFeature, " +```"), + #[stable(feature = "assoc_int_consts", since = "1.43.0")] + pub const MIN: Self = 0; + } + + doc_comment! { + concat!("The largest value that can be represented by this integer type. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(", stringify!($SelfT), "::MAX, ", stringify!($MaxV), ");", +$EndFeature, " +```"), + #[stable(feature = "assoc_int_consts", since = "1.43.0")] + pub const MAX: Self = !0; + } + + doc_comment! { + concat!("Converts a string slice in a given base to an integer. + +The string is expected to be an optional `+` sign +followed by digits. +Leading and trailing whitespace represent an error. +Digits are a subset of these characters, depending on `radix`: + +* `0-9` +* `a-z` +* `A-Z` + +# Panics + +This function panics if `radix` is not in the range from 2 to 36. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(", stringify!($SelfT), "::from_str_radix(\"A\", 16), Ok(10));", +$EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + pub fn from_str_radix(src: &str, radix: u32) -> Result<Self, ParseIntError> { + from_str_radix(src, radix) + } + } + + doc_comment! { + concat!("Returns the number of ones in the binary representation of `self`. + +# Examples + +Basic usage: + +``` +", $Feature, "let n = 0b01001100", stringify!($SelfT), "; + +assert_eq!(n.count_ones(), 3);", $EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_math", since = "1.32.0")] + #[inline] + pub const fn count_ones(self) -> u32 { + intrinsics::ctpop(self as $ActualT) as u32 + } + } + + doc_comment! { + concat!("Returns the number of zeros in the binary representation of `self`. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(", stringify!($SelfT), "::MAX.count_zeros(), 0);", $EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_math", since = "1.32.0")] + #[inline] + pub const fn count_zeros(self) -> u32 { + (!self).count_ones() + } + } + + doc_comment! { + concat!("Returns the number of leading zeros in the binary representation of `self`. + +# Examples + +Basic usage: + +``` +", $Feature, "let n = ", stringify!($SelfT), "::MAX >> 2; + +assert_eq!(n.leading_zeros(), 2);", $EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_math", since = "1.32.0")] + #[inline] + pub const fn leading_zeros(self) -> u32 { + intrinsics::ctlz(self as $ActualT) as u32 + } + } + + doc_comment! { + concat!("Returns the number of trailing zeros in the binary representation +of `self`. + +# Examples + +Basic usage: + +``` +", $Feature, "let n = 0b0101000", stringify!($SelfT), "; + +assert_eq!(n.trailing_zeros(), 3);", $EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_math", since = "1.32.0")] + #[inline] + pub const fn trailing_zeros(self) -> u32 { + intrinsics::cttz(self) as u32 + } + } + + doc_comment! { + concat!("Returns the number of leading ones in the binary representation of `self`. + +# Examples + +Basic usage: + +``` +", $Feature, "let n = !(", stringify!($SelfT), "::MAX >> 2); + +assert_eq!(n.leading_ones(), 2);", $EndFeature, " +```"), + #[stable(feature = "leading_trailing_ones", since = "1.46.0")] + #[rustc_const_stable(feature = "leading_trailing_ones", since = "1.46.0")] + #[inline] + pub const fn leading_ones(self) -> u32 { + (!self).leading_zeros() + } + } + + doc_comment! { + concat!("Returns the number of trailing ones in the binary representation +of `self`. + +# Examples + +Basic usage: + +``` +", $Feature, "let n = 0b1010111", stringify!($SelfT), "; + +assert_eq!(n.trailing_ones(), 3);", $EndFeature, " +```"), + #[stable(feature = "leading_trailing_ones", since = "1.46.0")] + #[rustc_const_stable(feature = "leading_trailing_ones", since = "1.46.0")] + #[inline] + pub const fn trailing_ones(self) -> u32 { + (!self).trailing_zeros() + } + } + + doc_comment! { + concat!("Shifts the bits to the left by a specified amount, `n`, +wrapping the truncated bits to the end of the resulting integer. + +Please note this isn't the same operation as the `<<` shifting operator! + +# Examples + +Basic usage: + +``` +let n = ", $rot_op, stringify!($SelfT), "; +let m = ", $rot_result, "; + +assert_eq!(n.rotate_left(", $rot, "), m); +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_math", since = "1.32.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn rotate_left(self, n: u32) -> Self { + intrinsics::rotate_left(self, n as $SelfT) + } + } + + doc_comment! { + concat!("Shifts the bits to the right by a specified amount, `n`, +wrapping the truncated bits to the beginning of the resulting +integer. + +Please note this isn't the same operation as the `>>` shifting operator! + +# Examples + +Basic usage: + +``` +let n = ", $rot_result, stringify!($SelfT), "; +let m = ", $rot_op, "; + +assert_eq!(n.rotate_right(", $rot, "), m); +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_math", since = "1.32.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn rotate_right(self, n: u32) -> Self { + intrinsics::rotate_right(self, n as $SelfT) + } + } + + doc_comment! { + concat!(" +Reverses the byte order of the integer. + +# Examples + +Basic usage: + +``` +let n = ", $swap_op, stringify!($SelfT), "; +let m = n.swap_bytes(); + +assert_eq!(m, ", $swapped, "); +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_math", since = "1.32.0")] + #[inline] + pub const fn swap_bytes(self) -> Self { + intrinsics::bswap(self as $ActualT) as Self + } + } + + doc_comment! { + concat!("Reverses the bit pattern of the integer. + +# Examples + +Basic usage: + +``` +let n = ", $swap_op, stringify!($SelfT), "; +let m = n.reverse_bits(); + +assert_eq!(m, ", $reversed, "); +```"), + #[stable(feature = "reverse_bits", since = "1.37.0")] + #[rustc_const_stable(feature = "const_math", since = "1.32.0")] + #[inline] + #[must_use] + pub const fn reverse_bits(self) -> Self { + intrinsics::bitreverse(self as $ActualT) as Self + } + } + + doc_comment! { + concat!("Converts an integer from big endian to the target's endianness. + +On big endian this is a no-op. On little endian the bytes are +swapped. + +# Examples + +Basic usage: + +``` +", $Feature, "let n = 0x1A", stringify!($SelfT), "; + +if cfg!(target_endian = \"big\") { + assert_eq!(", stringify!($SelfT), "::from_be(n), n) +} else { + assert_eq!(", stringify!($SelfT), "::from_be(n), n.swap_bytes()) +}", $EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_math", since = "1.32.0")] + #[inline] + pub const fn from_be(x: Self) -> Self { + #[cfg(target_endian = "big")] + { + x + } + #[cfg(not(target_endian = "big"))] + { + x.swap_bytes() + } + } + } + + doc_comment! { + concat!("Converts an integer from little endian to the target's endianness. + +On little endian this is a no-op. On big endian the bytes are +swapped. + +# Examples + +Basic usage: + +``` +", $Feature, "let n = 0x1A", stringify!($SelfT), "; + +if cfg!(target_endian = \"little\") { + assert_eq!(", stringify!($SelfT), "::from_le(n), n) +} else { + assert_eq!(", stringify!($SelfT), "::from_le(n), n.swap_bytes()) +}", $EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_math", since = "1.32.0")] + #[inline] + pub const fn from_le(x: Self) -> Self { + #[cfg(target_endian = "little")] + { + x + } + #[cfg(not(target_endian = "little"))] + { + x.swap_bytes() + } + } + } + + doc_comment! { + concat!("Converts `self` to big endian from the target's endianness. + +On big endian this is a no-op. On little endian the bytes are +swapped. + +# Examples + +Basic usage: + +``` +", $Feature, "let n = 0x1A", stringify!($SelfT), "; + +if cfg!(target_endian = \"big\") { + assert_eq!(n.to_be(), n) +} else { + assert_eq!(n.to_be(), n.swap_bytes()) +}", $EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_math", since = "1.32.0")] + #[inline] + pub const fn to_be(self) -> Self { // or not to be? + #[cfg(target_endian = "big")] + { + self + } + #[cfg(not(target_endian = "big"))] + { + self.swap_bytes() + } + } + } + + doc_comment! { + concat!("Converts `self` to little endian from the target's endianness. + +On little endian this is a no-op. On big endian the bytes are +swapped. + +# Examples + +Basic usage: + +``` +", $Feature, "let n = 0x1A", stringify!($SelfT), "; + +if cfg!(target_endian = \"little\") { + assert_eq!(n.to_le(), n) +} else { + assert_eq!(n.to_le(), n.swap_bytes()) +}", $EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_math", since = "1.32.0")] + #[inline] + pub const fn to_le(self) -> Self { + #[cfg(target_endian = "little")] + { + self + } + #[cfg(not(target_endian = "little"))] + { + self.swap_bytes() + } + } + } + + doc_comment! { + concat!("Checked integer addition. Computes `self + rhs`, returning `None` +if overflow occurred. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add(1), ", +"Some(", stringify!($SelfT), "::MAX - 1)); +assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add(3), None);", $EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn checked_add(self, rhs: Self) -> Option<Self> { + let (a, b) = self.overflowing_add(rhs); + if unlikely!(b) {None} else {Some(a)} + } + } + + doc_comment! { + concat!("Unchecked integer addition. Computes `self + rhs`, assuming overflow +cannot occur. This results in undefined behavior when `self + rhs > ", stringify!($SelfT), +"::MAX` or `self + rhs < ", stringify!($SelfT), "::MIN`."), + #[unstable( + feature = "unchecked_math", + reason = "niche optimization path", + issue = "none", + )] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub unsafe fn unchecked_add(self, rhs: Self) -> Self { + // SAFETY: the caller must uphold the safety contract for + // `unchecked_add`. + unsafe { intrinsics::unchecked_add(self, rhs) } + } + } + + doc_comment! { + concat!("Checked integer subtraction. Computes `self - rhs`, returning +`None` if overflow occurred. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(1", stringify!($SelfT), ".checked_sub(1), Some(0)); +assert_eq!(0", stringify!($SelfT), ".checked_sub(1), None);", $EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn checked_sub(self, rhs: Self) -> Option<Self> { + let (a, b) = self.overflowing_sub(rhs); + if unlikely!(b) {None} else {Some(a)} + } + } + + doc_comment! { + concat!("Unchecked integer subtraction. Computes `self - rhs`, assuming overflow +cannot occur. This results in undefined behavior when `self - rhs > ", stringify!($SelfT), +"::MAX` or `self - rhs < ", stringify!($SelfT), "::MIN`."), + #[unstable( + feature = "unchecked_math", + reason = "niche optimization path", + issue = "none", + )] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub unsafe fn unchecked_sub(self, rhs: Self) -> Self { + // SAFETY: the caller must uphold the safety contract for + // `unchecked_sub`. + unsafe { intrinsics::unchecked_sub(self, rhs) } + } + } + + doc_comment! { + concat!("Checked integer multiplication. Computes `self * rhs`, returning +`None` if overflow occurred. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(5", stringify!($SelfT), ".checked_mul(1), Some(5)); +assert_eq!(", stringify!($SelfT), "::MAX.checked_mul(2), None);", $EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn checked_mul(self, rhs: Self) -> Option<Self> { + let (a, b) = self.overflowing_mul(rhs); + if unlikely!(b) {None} else {Some(a)} + } + } + + doc_comment! { + concat!("Unchecked integer multiplication. Computes `self * rhs`, assuming overflow +cannot occur. This results in undefined behavior when `self * rhs > ", stringify!($SelfT), +"::MAX` or `self * rhs < ", stringify!($SelfT), "::MIN`."), + #[unstable( + feature = "unchecked_math", + reason = "niche optimization path", + issue = "none", + )] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub unsafe fn unchecked_mul(self, rhs: Self) -> Self { + // SAFETY: the caller must uphold the safety contract for + // `unchecked_mul`. + unsafe { intrinsics::unchecked_mul(self, rhs) } + } + } + + doc_comment! { + concat!("Checked integer division. Computes `self / rhs`, returning `None` +if `rhs == 0`. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(128", stringify!($SelfT), ".checked_div(2), Some(64)); +assert_eq!(1", stringify!($SelfT), ".checked_div(0), None);", $EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_unstable(feature = "const_checked_int_methods", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn checked_div(self, rhs: Self) -> Option<Self> { + if unlikely!(rhs == 0) { + None + } else { + // SAFETY: div by zero has been checked above and unsigned types have no other + // failure modes for division + Some(unsafe { intrinsics::unchecked_div(self, rhs) }) + } + } + } + + doc_comment! { + concat!("Checked Euclidean division. Computes `self.div_euclid(rhs)`, returning `None` +if `rhs == 0`. + +# Examples + +Basic usage: + +``` +assert_eq!(128", stringify!($SelfT), ".checked_div_euclid(2), Some(64)); +assert_eq!(1", stringify!($SelfT), ".checked_div_euclid(0), None); +```"), + #[stable(feature = "euclidean_division", since = "1.38.0")] + #[rustc_const_unstable(feature = "const_euclidean_int_methods", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn checked_div_euclid(self, rhs: Self) -> Option<Self> { + if unlikely!(rhs == 0) { + None + } else { + Some(self.div_euclid(rhs)) + } + } + } + + + doc_comment! { + concat!("Checked integer remainder. Computes `self % rhs`, returning `None` +if `rhs == 0`. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(5", stringify!($SelfT), ".checked_rem(2), Some(1)); +assert_eq!(5", stringify!($SelfT), ".checked_rem(0), None);", $EndFeature, " +```"), + #[stable(feature = "wrapping", since = "1.7.0")] + #[rustc_const_unstable(feature = "const_checked_int_methods", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn checked_rem(self, rhs: Self) -> Option<Self> { + if unlikely!(rhs == 0) { + None + } else { + // SAFETY: div by zero has been checked above and unsigned types have no other + // failure modes for division + Some(unsafe { intrinsics::unchecked_rem(self, rhs) }) + } + } + } + + doc_comment! { + concat!("Checked Euclidean modulo. Computes `self.rem_euclid(rhs)`, returning `None` +if `rhs == 0`. + +# Examples + +Basic usage: + +``` +assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(2), Some(1)); +assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(0), None); +```"), + #[stable(feature = "euclidean_division", since = "1.38.0")] + #[rustc_const_unstable(feature = "const_euclidean_int_methods", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn checked_rem_euclid(self, rhs: Self) -> Option<Self> { + if unlikely!(rhs == 0) { + None + } else { + Some(self.rem_euclid(rhs)) + } + } + } + + doc_comment! { + concat!("Checked negation. Computes `-self`, returning `None` unless `self == +0`. + +Note that negating any positive integer will overflow. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(0", stringify!($SelfT), ".checked_neg(), Some(0)); +assert_eq!(1", stringify!($SelfT), ".checked_neg(), None);", $EndFeature, " +```"), + #[stable(feature = "wrapping", since = "1.7.0")] + #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")] + #[inline] + pub const fn checked_neg(self) -> Option<Self> { + let (a, b) = self.overflowing_neg(); + if unlikely!(b) {None} else {Some(a)} + } + } + + doc_comment! { + concat!("Checked shift left. Computes `self << rhs`, returning `None` +if `rhs` is larger than or equal to the number of bits in `self`. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(0x1", stringify!($SelfT), ".checked_shl(4), Some(0x10)); +assert_eq!(0x10", stringify!($SelfT), ".checked_shl(129), None);", $EndFeature, " +```"), + #[stable(feature = "wrapping", since = "1.7.0")] + #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn checked_shl(self, rhs: u32) -> Option<Self> { + let (a, b) = self.overflowing_shl(rhs); + if unlikely!(b) {None} else {Some(a)} + } + } + + doc_comment! { + concat!("Checked shift right. Computes `self >> rhs`, returning `None` +if `rhs` is larger than or equal to the number of bits in `self`. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(0x10", stringify!($SelfT), ".checked_shr(4), Some(0x1)); +assert_eq!(0x10", stringify!($SelfT), ".checked_shr(129), None);", $EndFeature, " +```"), + #[stable(feature = "wrapping", since = "1.7.0")] + #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn checked_shr(self, rhs: u32) -> Option<Self> { + let (a, b) = self.overflowing_shr(rhs); + if unlikely!(b) {None} else {Some(a)} + } + } + + doc_comment! { + concat!("Checked exponentiation. Computes `self.pow(exp)`, returning `None` if +overflow occurred. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(2", stringify!($SelfT), ".checked_pow(5), Some(32)); +assert_eq!(", stringify!($SelfT), "::MAX.checked_pow(2), None);", $EndFeature, " +```"), + #[stable(feature = "no_panic_pow", since = "1.34.0")] + #[rustc_const_unstable(feature = "const_int_pow", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn checked_pow(self, mut exp: u32) -> Option<Self> { + if exp == 0 { + return Some(1); + } + let mut base = self; + let mut acc: Self = 1; + + while exp > 1 { + if (exp & 1) == 1 { + acc = try_opt!(acc.checked_mul(base)); + } + exp /= 2; + base = try_opt!(base.checked_mul(base)); + } + + // since exp!=0, finally the exp must be 1. + // Deal with the final bit of the exponent separately, since + // squaring the base afterwards is not necessary and may cause a + // needless overflow. + + Some(try_opt!(acc.checked_mul(base))) + } + } + + doc_comment! { + concat!("Saturating integer addition. Computes `self + rhs`, saturating at +the numeric bounds instead of overflowing. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(100", stringify!($SelfT), ".saturating_add(1), 101); +assert_eq!(", stringify!($SelfT), "::MAX.saturating_add(127), ", stringify!($SelfT), "::MAX);", +$EndFeature, " +```"), + + #[stable(feature = "rust1", since = "1.0.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")] + #[inline] + pub const fn saturating_add(self, rhs: Self) -> Self { + intrinsics::saturating_add(self, rhs) + } + } + + doc_comment! { + concat!("Saturating integer subtraction. Computes `self - rhs`, saturating +at the numeric bounds instead of overflowing. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(100", stringify!($SelfT), ".saturating_sub(27), 73); +assert_eq!(13", stringify!($SelfT), ".saturating_sub(127), 0);", $EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")] + #[inline] + pub const fn saturating_sub(self, rhs: Self) -> Self { + intrinsics::saturating_sub(self, rhs) + } + } + + doc_comment! { + concat!("Saturating integer multiplication. Computes `self * rhs`, +saturating at the numeric bounds instead of overflowing. + +# Examples + +Basic usage: + +``` +", $Feature, " +assert_eq!(2", stringify!($SelfT), ".saturating_mul(10), 20); +assert_eq!((", stringify!($SelfT), "::MAX).saturating_mul(10), ", stringify!($SelfT), +"::MAX);", $EndFeature, " +```"), + #[stable(feature = "wrapping", since = "1.7.0")] + #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn saturating_mul(self, rhs: Self) -> Self { + match self.checked_mul(rhs) { + Some(x) => x, + None => Self::MAX, + } + } + } + + doc_comment! { + concat!("Saturating integer exponentiation. Computes `self.pow(exp)`, +saturating at the numeric bounds instead of overflowing. + +# Examples + +Basic usage: + +``` +", $Feature, " +assert_eq!(4", stringify!($SelfT), ".saturating_pow(3), 64); +assert_eq!(", stringify!($SelfT), "::MAX.saturating_pow(2), ", stringify!($SelfT), "::MAX);", +$EndFeature, " +```"), + #[stable(feature = "no_panic_pow", since = "1.34.0")] + #[rustc_const_unstable(feature = "const_int_pow", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn saturating_pow(self, exp: u32) -> Self { + match self.checked_pow(exp) { + Some(x) => x, + None => Self::MAX, + } + } + } + + doc_comment! { + concat!("Wrapping (modular) addition. Computes `self + rhs`, +wrapping around at the boundary of the type. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(200", stringify!($SelfT), ".wrapping_add(55), 255); +assert_eq!(200", stringify!($SelfT), ".wrapping_add(", stringify!($SelfT), "::MAX), 199);", +$EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn wrapping_add(self, rhs: Self) -> Self { + intrinsics::wrapping_add(self, rhs) + } + } + + doc_comment! { + concat!("Wrapping (modular) subtraction. Computes `self - rhs`, +wrapping around at the boundary of the type. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(100", stringify!($SelfT), ".wrapping_sub(100), 0); +assert_eq!(100", stringify!($SelfT), ".wrapping_sub(", stringify!($SelfT), "::MAX), 101);", +$EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn wrapping_sub(self, rhs: Self) -> Self { + intrinsics::wrapping_sub(self, rhs) + } + } + + /// Wrapping (modular) multiplication. Computes `self * + /// rhs`, wrapping around at the boundary of the type. + /// + /// # Examples + /// + /// Basic usage: + /// + /// Please note that this example is shared between integer types. + /// Which explains why `u8` is used here. + /// + /// ``` + /// assert_eq!(10u8.wrapping_mul(12), 120); + /// assert_eq!(25u8.wrapping_mul(12), 44); + /// ``` + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn wrapping_mul(self, rhs: Self) -> Self { + intrinsics::wrapping_mul(self, rhs) + } + + doc_comment! { + concat!("Wrapping (modular) division. Computes `self / rhs`. +Wrapped division on unsigned types is just normal division. +There's no way wrapping could ever happen. +This function exists, so that all operations +are accounted for in the wrapping operations. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(100", stringify!($SelfT), ".wrapping_div(10), 10);", $EndFeature, " +```"), + #[stable(feature = "num_wrapping", since = "1.2.0")] + #[rustc_const_unstable(feature = "const_wrapping_int_methods", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn wrapping_div(self, rhs: Self) -> Self { + self / rhs + } + } + + doc_comment! { + concat!("Wrapping Euclidean division. Computes `self.div_euclid(rhs)`. +Wrapped division on unsigned types is just normal division. +There's no way wrapping could ever happen. +This function exists, so that all operations +are accounted for in the wrapping operations. +Since, for the positive integers, all common +definitions of division are equal, this +is exactly equal to `self.wrapping_div(rhs)`. + +# Examples + +Basic usage: + +``` +assert_eq!(100", stringify!($SelfT), ".wrapping_div_euclid(10), 10); +```"), + #[stable(feature = "euclidean_division", since = "1.38.0")] + #[rustc_const_unstable(feature = "const_euclidean_int_methods", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn wrapping_div_euclid(self, rhs: Self) -> Self { + self / rhs + } + } + + doc_comment! { + concat!("Wrapping (modular) remainder. Computes `self % rhs`. +Wrapped remainder calculation on unsigned types is +just the regular remainder calculation. +There's no way wrapping could ever happen. +This function exists, so that all operations +are accounted for in the wrapping operations. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(100", stringify!($SelfT), ".wrapping_rem(10), 0);", $EndFeature, " +```"), + #[stable(feature = "num_wrapping", since = "1.2.0")] + #[rustc_const_unstable(feature = "const_wrapping_int_methods", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn wrapping_rem(self, rhs: Self) -> Self { + self % rhs + } + } + + doc_comment! { + concat!("Wrapping Euclidean modulo. Computes `self.rem_euclid(rhs)`. +Wrapped modulo calculation on unsigned types is +just the regular remainder calculation. +There's no way wrapping could ever happen. +This function exists, so that all operations +are accounted for in the wrapping operations. +Since, for the positive integers, all common +definitions of division are equal, this +is exactly equal to `self.wrapping_rem(rhs)`. + +# Examples + +Basic usage: + +``` +assert_eq!(100", stringify!($SelfT), ".wrapping_rem_euclid(10), 0); +```"), + #[stable(feature = "euclidean_division", since = "1.38.0")] + #[rustc_const_unstable(feature = "const_euclidean_int_methods", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn wrapping_rem_euclid(self, rhs: Self) -> Self { + self % rhs + } + } + + /// Wrapping (modular) negation. Computes `-self`, + /// wrapping around at the boundary of the type. + /// + /// Since unsigned types do not have negative equivalents + /// all applications of this function will wrap (except for `-0`). + /// For values smaller than the corresponding signed type's maximum + /// the result is the same as casting the corresponding signed value. + /// Any larger values are equivalent to `MAX + 1 - (val - MAX - 1)` where + /// `MAX` is the corresponding signed type's maximum. + /// + /// # Examples + /// + /// Basic usage: + /// + /// Please note that this example is shared between integer types. + /// Which explains why `i8` is used here. + /// + /// ``` + /// assert_eq!(100i8.wrapping_neg(), -100); + /// assert_eq!((-128i8).wrapping_neg(), -128); + /// ``` + #[stable(feature = "num_wrapping", since = "1.2.0")] + #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")] + #[inline] + pub const fn wrapping_neg(self) -> Self { + self.overflowing_neg().0 + } + + doc_comment! { + concat!("Panic-free bitwise shift-left; yields `self << mask(rhs)`, +where `mask` removes any high-order bits of `rhs` that +would cause the shift to exceed the bitwidth of the type. + +Note that this is *not* the same as a rotate-left; the +RHS of a wrapping shift-left is restricted to the range +of the type, rather than the bits shifted out of the LHS +being returned to the other end. The primitive integer +types all implement a [`rotate_left`](#method.rotate_left) function, +which may be what you want instead. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(1", stringify!($SelfT), ".wrapping_shl(7), 128); +assert_eq!(1", stringify!($SelfT), ".wrapping_shl(128), 1);", $EndFeature, " +```"), + #[stable(feature = "num_wrapping", since = "1.2.0")] + #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn wrapping_shl(self, rhs: u32) -> Self { + // SAFETY: the masking by the bitsize of the type ensures that we do not shift + // out of bounds + unsafe { + intrinsics::unchecked_shl(self, (rhs & ($BITS - 1)) as $SelfT) + } + } + } + + doc_comment! { + concat!("Panic-free bitwise shift-right; yields `self >> mask(rhs)`, +where `mask` removes any high-order bits of `rhs` that +would cause the shift to exceed the bitwidth of the type. + +Note that this is *not* the same as a rotate-right; the +RHS of a wrapping shift-right is restricted to the range +of the type, rather than the bits shifted out of the LHS +being returned to the other end. The primitive integer +types all implement a [`rotate_right`](#method.rotate_right) function, +which may be what you want instead. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(128", stringify!($SelfT), ".wrapping_shr(7), 1); +assert_eq!(128", stringify!($SelfT), ".wrapping_shr(128), 128);", $EndFeature, " +```"), + #[stable(feature = "num_wrapping", since = "1.2.0")] + #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn wrapping_shr(self, rhs: u32) -> Self { + // SAFETY: the masking by the bitsize of the type ensures that we do not shift + // out of bounds + unsafe { + intrinsics::unchecked_shr(self, (rhs & ($BITS - 1)) as $SelfT) + } + } + } + + doc_comment! { + concat!("Wrapping (modular) exponentiation. Computes `self.pow(exp)`, +wrapping around at the boundary of the type. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(3", stringify!($SelfT), ".wrapping_pow(5), 243); +assert_eq!(3u8.wrapping_pow(6), 217);", $EndFeature, " +```"), + #[stable(feature = "no_panic_pow", since = "1.34.0")] + #[rustc_const_unstable(feature = "const_int_pow", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn wrapping_pow(self, mut exp: u32) -> Self { + if exp == 0 { + return 1; + } + let mut base = self; + let mut acc: Self = 1; + + while exp > 1 { + if (exp & 1) == 1 { + acc = acc.wrapping_mul(base); + } + exp /= 2; + base = base.wrapping_mul(base); + } + + // since exp!=0, finally the exp must be 1. + // Deal with the final bit of the exponent separately, since + // squaring the base afterwards is not necessary and may cause a + // needless overflow. + acc.wrapping_mul(base) + } + } + + doc_comment! { + concat!("Calculates `self` + `rhs` + +Returns a tuple of the addition along with a boolean indicating +whether an arithmetic overflow would occur. If an overflow would +have occurred then the wrapped value is returned. + +# Examples + +Basic usage + +``` +", $Feature, " +assert_eq!(5", stringify!($SelfT), ".overflowing_add(2), (7, false)); +assert_eq!(", stringify!($SelfT), "::MAX.overflowing_add(1), (0, true));", $EndFeature, " +```"), + #[stable(feature = "wrapping", since = "1.7.0")] + #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn overflowing_add(self, rhs: Self) -> (Self, bool) { + let (a, b) = intrinsics::add_with_overflow(self as $ActualT, rhs as $ActualT); + (a as Self, b) + } + } + + doc_comment! { + concat!("Calculates `self` - `rhs` + +Returns a tuple of the subtraction along with a boolean indicating +whether an arithmetic overflow would occur. If an overflow would +have occurred then the wrapped value is returned. + +# Examples + +Basic usage + +``` +", $Feature, " +assert_eq!(5", stringify!($SelfT), ".overflowing_sub(2), (3, false)); +assert_eq!(0", stringify!($SelfT), ".overflowing_sub(1), (", stringify!($SelfT), "::MAX, true));", +$EndFeature, " +```"), + #[stable(feature = "wrapping", since = "1.7.0")] + #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn overflowing_sub(self, rhs: Self) -> (Self, bool) { + let (a, b) = intrinsics::sub_with_overflow(self as $ActualT, rhs as $ActualT); + (a as Self, b) + } + } + + /// Calculates the multiplication of `self` and `rhs`. + /// + /// Returns a tuple of the multiplication along with a boolean + /// indicating whether an arithmetic overflow would occur. If an + /// overflow would have occurred then the wrapped value is returned. + /// + /// # Examples + /// + /// Basic usage: + /// + /// Please note that this example is shared between integer types. + /// Which explains why `u32` is used here. + /// + /// ``` + /// assert_eq!(5u32.overflowing_mul(2), (10, false)); + /// assert_eq!(1_000_000_000u32.overflowing_mul(10), (1410065408, true)); + /// ``` + #[stable(feature = "wrapping", since = "1.7.0")] + #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn overflowing_mul(self, rhs: Self) -> (Self, bool) { + let (a, b) = intrinsics::mul_with_overflow(self as $ActualT, rhs as $ActualT); + (a as Self, b) + } + + doc_comment! { + concat!("Calculates the divisor when `self` is divided by `rhs`. + +Returns a tuple of the divisor along with a boolean indicating +whether an arithmetic overflow would occur. Note that for unsigned +integers overflow never occurs, so the second value is always +`false`. + +# Panics + +This function will panic if `rhs` is 0. + +# Examples + +Basic usage + +``` +", $Feature, "assert_eq!(5", stringify!($SelfT), ".overflowing_div(2), (2, false));", $EndFeature, " +```"), + #[inline] + #[stable(feature = "wrapping", since = "1.7.0")] + #[rustc_const_unstable(feature = "const_overflowing_int_methods", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + pub const fn overflowing_div(self, rhs: Self) -> (Self, bool) { + (self / rhs, false) + } + } + + doc_comment! { + concat!("Calculates the quotient of Euclidean division `self.div_euclid(rhs)`. + +Returns a tuple of the divisor along with a boolean indicating +whether an arithmetic overflow would occur. Note that for unsigned +integers overflow never occurs, so the second value is always +`false`. +Since, for the positive integers, all common +definitions of division are equal, this +is exactly equal to `self.overflowing_div(rhs)`. + +# Panics + +This function will panic if `rhs` is 0. + +# Examples + +Basic usage + +``` +assert_eq!(5", stringify!($SelfT), ".overflowing_div_euclid(2), (2, false)); +```"), + #[inline] + #[stable(feature = "euclidean_division", since = "1.38.0")] + #[rustc_const_unstable(feature = "const_euclidean_int_methods", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + pub const fn overflowing_div_euclid(self, rhs: Self) -> (Self, bool) { + (self / rhs, false) + } + } + + doc_comment! { + concat!("Calculates the remainder when `self` is divided by `rhs`. + +Returns a tuple of the remainder after dividing along with a boolean +indicating whether an arithmetic overflow would occur. Note that for +unsigned integers overflow never occurs, so the second value is +always `false`. + +# Panics + +This function will panic if `rhs` is 0. + +# Examples + +Basic usage + +``` +", $Feature, "assert_eq!(5", stringify!($SelfT), ".overflowing_rem(2), (1, false));", $EndFeature, " +```"), + #[inline] + #[stable(feature = "wrapping", since = "1.7.0")] + #[rustc_const_unstable(feature = "const_overflowing_int_methods", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + pub const fn overflowing_rem(self, rhs: Self) -> (Self, bool) { + (self % rhs, false) + } + } + + doc_comment! { + concat!("Calculates the remainder `self.rem_euclid(rhs)` as if by Euclidean division. + +Returns a tuple of the modulo after dividing along with a boolean +indicating whether an arithmetic overflow would occur. Note that for +unsigned integers overflow never occurs, so the second value is +always `false`. +Since, for the positive integers, all common +definitions of division are equal, this operation +is exactly equal to `self.overflowing_rem(rhs)`. + +# Panics + +This function will panic if `rhs` is 0. + +# Examples + +Basic usage + +``` +assert_eq!(5", stringify!($SelfT), ".overflowing_rem_euclid(2), (1, false)); +```"), + #[inline] + #[stable(feature = "euclidean_division", since = "1.38.0")] + #[rustc_const_unstable(feature = "const_euclidean_int_methods", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + pub const fn overflowing_rem_euclid(self, rhs: Self) -> (Self, bool) { + (self % rhs, false) + } + } + + doc_comment! { + concat!("Negates self in an overflowing fashion. + +Returns `!self + 1` using wrapping operations to return the value +that represents the negation of this unsigned value. Note that for +positive unsigned values overflow always occurs, but negating 0 does +not overflow. + +# Examples + +Basic usage + +``` +", $Feature, "assert_eq!(0", stringify!($SelfT), ".overflowing_neg(), (0, false)); +assert_eq!(2", stringify!($SelfT), ".overflowing_neg(), (-2i32 as ", stringify!($SelfT), +", true));", $EndFeature, " +```"), + #[inline] + #[stable(feature = "wrapping", since = "1.7.0")] + #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")] + pub const fn overflowing_neg(self) -> (Self, bool) { + ((!self).wrapping_add(1), self != 0) + } + } + + doc_comment! { + concat!("Shifts self left by `rhs` bits. + +Returns a tuple of the shifted version of self along with a boolean +indicating whether the shift value was larger than or equal to the +number of bits. If the shift value is too large, then value is +masked (N-1) where N is the number of bits, and this value is then +used to perform the shift. + +# Examples + +Basic usage + +``` +", $Feature, "assert_eq!(0x1", stringify!($SelfT), ".overflowing_shl(4), (0x10, false)); +assert_eq!(0x1", stringify!($SelfT), ".overflowing_shl(132), (0x10, true));", $EndFeature, " +```"), + #[stable(feature = "wrapping", since = "1.7.0")] + #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn overflowing_shl(self, rhs: u32) -> (Self, bool) { + (self.wrapping_shl(rhs), (rhs > ($BITS - 1))) + } + } + + doc_comment! { + concat!("Shifts self right by `rhs` bits. + +Returns a tuple of the shifted version of self along with a boolean +indicating whether the shift value was larger than or equal to the +number of bits. If the shift value is too large, then value is +masked (N-1) where N is the number of bits, and this value is then +used to perform the shift. + +# Examples + +Basic usage + +``` +", $Feature, "assert_eq!(0x10", stringify!($SelfT), ".overflowing_shr(4), (0x1, false)); +assert_eq!(0x10", stringify!($SelfT), ".overflowing_shr(132), (0x1, true));", $EndFeature, " +```"), + #[stable(feature = "wrapping", since = "1.7.0")] + #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn overflowing_shr(self, rhs: u32) -> (Self, bool) { + (self.wrapping_shr(rhs), (rhs > ($BITS - 1))) + } + } + + doc_comment! { + concat!("Raises self to the power of `exp`, using exponentiation by squaring. + +Returns a tuple of the exponentiation along with a bool indicating +whether an overflow happened. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(3", stringify!($SelfT), ".overflowing_pow(5), (243, false)); +assert_eq!(3u8.overflowing_pow(6), (217, true));", $EndFeature, " +```"), + #[stable(feature = "no_panic_pow", since = "1.34.0")] + #[rustc_const_unstable(feature = "const_int_pow", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + pub const fn overflowing_pow(self, mut exp: u32) -> (Self, bool) { + if exp == 0{ + return (1,false); + } + let mut base = self; + let mut acc: Self = 1; + let mut overflown = false; + // Scratch space for storing results of overflowing_mul. + let mut r; + + while exp > 1 { + if (exp & 1) == 1 { + r = acc.overflowing_mul(base); + acc = r.0; + overflown |= r.1; + } + exp /= 2; + r = base.overflowing_mul(base); + base = r.0; + overflown |= r.1; + } + + // since exp!=0, finally the exp must be 1. + // Deal with the final bit of the exponent separately, since + // squaring the base afterwards is not necessary and may cause a + // needless overflow. + r = acc.overflowing_mul(base); + r.1 |= overflown; + + r + } + } + + doc_comment! { + concat!("Raises self to the power of `exp`, using exponentiation by squaring. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(2", stringify!($SelfT), ".pow(5), 32);", $EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_unstable(feature = "const_int_pow", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + #[rustc_inherit_overflow_checks] + pub const fn pow(self, mut exp: u32) -> Self { + if exp == 0 { + return 1; + } + let mut base = self; + let mut acc = 1; + + while exp > 1 { + if (exp & 1) == 1 { + acc = acc * base; + } + exp /= 2; + base = base * base; + } + + // since exp!=0, finally the exp must be 1. + // Deal with the final bit of the exponent separately, since + // squaring the base afterwards is not necessary and may cause a + // needless overflow. + acc * base + } + } + + doc_comment! { + concat!("Performs Euclidean division. + +Since, for the positive integers, all common +definitions of division are equal, this +is exactly equal to `self / rhs`. + +# Panics + +This function will panic if `rhs` is 0. + +# Examples + +Basic usage: + +``` +assert_eq!(7", stringify!($SelfT), ".div_euclid(4), 1); // or any other integer type +```"), + #[stable(feature = "euclidean_division", since = "1.38.0")] + #[rustc_const_unstable(feature = "const_euclidean_int_methods", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + #[rustc_inherit_overflow_checks] + pub const fn div_euclid(self, rhs: Self) -> Self { + self / rhs + } + } + + + doc_comment! { + concat!("Calculates the least remainder of `self (mod rhs)`. + +Since, for the positive integers, all common +definitions of division are equal, this +is exactly equal to `self % rhs`. + +# Panics + +This function will panic if `rhs` is 0. + +# Examples + +Basic usage: + +``` +assert_eq!(7", stringify!($SelfT), ".rem_euclid(4), 3); // or any other integer type +```"), + #[stable(feature = "euclidean_division", since = "1.38.0")] + #[rustc_const_unstable(feature = "const_euclidean_int_methods", issue = "53718")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[inline] + #[rustc_inherit_overflow_checks] + pub const fn rem_euclid(self, rhs: Self) -> Self { + self % rhs + } + } + + doc_comment! { + concat!("Returns `true` if and only if `self == 2^k` for some `k`. + +# Examples + +Basic usage: + +``` +", $Feature, "assert!(16", stringify!($SelfT), ".is_power_of_two()); +assert!(!10", stringify!($SelfT), ".is_power_of_two());", $EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_stable(feature = "const_is_power_of_two", since = "1.32.0")] + #[inline] + pub const fn is_power_of_two(self) -> bool { + self.count_ones() == 1 + } + } + + // Returns one less than next power of two. + // (For 8u8 next power of two is 8u8 and for 6u8 it is 8u8) + // + // 8u8.one_less_than_next_power_of_two() == 7 + // 6u8.one_less_than_next_power_of_two() == 7 + // + // This method cannot overflow, as in the `next_power_of_two` + // overflow cases it instead ends up returning the maximum value + // of the type, and can return 0 for 0. + #[inline] + #[rustc_const_unstable(feature = "const_int_pow", issue = "53718")] + const fn one_less_than_next_power_of_two(self) -> Self { + if self <= 1 { return 0; } + + let p = self - 1; + // SAFETY: Because `p > 0`, it cannot consist entirely of leading zeros. + // That means the shift is always in-bounds, and some processors + // (such as intel pre-haswell) have more efficient ctlz + // intrinsics when the argument is non-zero. + let z = unsafe { intrinsics::ctlz_nonzero(p) }; + <$SelfT>::MAX >> z + } + + doc_comment! { + concat!("Returns the smallest power of two greater than or equal to `self`. + +When return value overflows (i.e., `self > (1 << (N-1))` for type +`uN`), it panics in debug mode and return value is wrapped to 0 in +release mode (the only situation in which method can return 0). + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(2", stringify!($SelfT), ".next_power_of_two(), 2); +assert_eq!(3", stringify!($SelfT), ".next_power_of_two(), 4);", $EndFeature, " +```"), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_unstable(feature = "const_int_pow", issue = "53718")] + #[inline] + #[rustc_inherit_overflow_checks] + pub const fn next_power_of_two(self) -> Self { + self.one_less_than_next_power_of_two() + 1 + } + } + + doc_comment! { + concat!("Returns the smallest power of two greater than or equal to `n`. If +the next power of two is greater than the type's maximum value, +`None` is returned, otherwise the power of two is wrapped in `Some`. + +# Examples + +Basic usage: + +``` +", $Feature, "assert_eq!(2", stringify!($SelfT), +".checked_next_power_of_two(), Some(2)); +assert_eq!(3", stringify!($SelfT), ".checked_next_power_of_two(), Some(4)); +assert_eq!(", stringify!($SelfT), "::MAX.checked_next_power_of_two(), None);", +$EndFeature, " +```"), + #[inline] + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_const_unstable(feature = "const_int_pow", issue = "53718")] + pub const fn checked_next_power_of_two(self) -> Option<Self> { + self.one_less_than_next_power_of_two().checked_add(1) + } + } + + doc_comment! { + concat!("Returns the smallest power of two greater than or equal to `n`. If +the next power of two is greater than the type's maximum value, +the return value is wrapped to `0`. + +# Examples + +Basic usage: + +``` +#![feature(wrapping_next_power_of_two)] +", $Feature, " +assert_eq!(2", stringify!($SelfT), ".wrapping_next_power_of_two(), 2); +assert_eq!(3", stringify!($SelfT), ".wrapping_next_power_of_two(), 4); +assert_eq!(", stringify!($SelfT), "::MAX.wrapping_next_power_of_two(), 0);", +$EndFeature, " +```"), + #[unstable(feature = "wrapping_next_power_of_two", issue = "32463", + reason = "needs decision on wrapping behaviour")] + #[rustc_const_unstable(feature = "const_int_pow", issue = "53718")] + pub const fn wrapping_next_power_of_two(self) -> Self { + self.one_less_than_next_power_of_two().wrapping_add(1) + } + } + + doc_comment! { + concat!("Return the memory representation of this integer as a byte array in +big-endian (network) byte order. +", +$to_xe_bytes_doc, +" +# Examples + +``` +let bytes = ", $swap_op, stringify!($SelfT), ".to_be_bytes(); +assert_eq!(bytes, ", $be_bytes, "); +```"), + #[stable(feature = "int_to_from_bytes", since = "1.32.0")] + #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")] + #[inline] + pub const fn to_be_bytes(self) -> [u8; mem::size_of::<Self>()] { + self.to_be().to_ne_bytes() + } + } + + doc_comment! { + concat!("Return the memory representation of this integer as a byte array in +little-endian byte order. +", +$to_xe_bytes_doc, +" +# Examples + +``` +let bytes = ", $swap_op, stringify!($SelfT), ".to_le_bytes(); +assert_eq!(bytes, ", $le_bytes, "); +```"), + #[stable(feature = "int_to_from_bytes", since = "1.32.0")] + #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")] + #[inline] + pub const fn to_le_bytes(self) -> [u8; mem::size_of::<Self>()] { + self.to_le().to_ne_bytes() + } + } + + doc_comment! { + concat!(" +Return the memory representation of this integer as a byte array in +native byte order. + +As the target platform's native endianness is used, portable code +should use [`to_be_bytes`] or [`to_le_bytes`], as appropriate, +instead. +", +$to_xe_bytes_doc, +" +[`to_be_bytes`]: #method.to_be_bytes +[`to_le_bytes`]: #method.to_le_bytes + +# Examples + +``` +let bytes = ", $swap_op, stringify!($SelfT), ".to_ne_bytes(); +assert_eq!( + bytes, + if cfg!(target_endian = \"big\") { + ", $be_bytes, " + } else { + ", $le_bytes, " + } +); +```"), + #[stable(feature = "int_to_from_bytes", since = "1.32.0")] + #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")] + // SAFETY: const sound because integers are plain old datatypes so we can always + // transmute them to arrays of bytes + #[allow_internal_unstable(const_fn_union)] + #[inline] + pub const fn to_ne_bytes(self) -> [u8; mem::size_of::<Self>()] { + #[repr(C)] + union Bytes { + val: $SelfT, + bytes: [u8; mem::size_of::<$SelfT>()], + } + // SAFETY: integers are plain old datatypes so we can always transmute them to + // arrays of bytes + unsafe { Bytes { val: self }.bytes } + } + } + + doc_comment! { + concat!("Create an integer value from its representation as a byte array in +big endian. +", +$from_xe_bytes_doc, +" +# Examples + +``` +let value = ", stringify!($SelfT), "::from_be_bytes(", $be_bytes, "); +assert_eq!(value, ", $swap_op, "); +``` + +When starting from a slice rather than an array, fallible conversion APIs can be used: + +``` +use std::convert::TryInto; + +fn read_be_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " { + let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">()); + *input = rest; + ", stringify!($SelfT), "::from_be_bytes(int_bytes.try_into().unwrap()) +} +```"), + #[stable(feature = "int_to_from_bytes", since = "1.32.0")] + #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")] + #[inline] + pub const fn from_be_bytes(bytes: [u8; mem::size_of::<Self>()]) -> Self { + Self::from_be(Self::from_ne_bytes(bytes)) + } + } + + doc_comment! { + concat!(" +Create an integer value from its representation as a byte array in +little endian. +", +$from_xe_bytes_doc, +" +# Examples + +``` +let value = ", stringify!($SelfT), "::from_le_bytes(", $le_bytes, "); +assert_eq!(value, ", $swap_op, "); +``` + +When starting from a slice rather than an array, fallible conversion APIs can be used: + +``` +use std::convert::TryInto; + +fn read_le_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " { + let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">()); + *input = rest; + ", stringify!($SelfT), "::from_le_bytes(int_bytes.try_into().unwrap()) +} +```"), + #[stable(feature = "int_to_from_bytes", since = "1.32.0")] + #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")] + #[inline] + pub const fn from_le_bytes(bytes: [u8; mem::size_of::<Self>()]) -> Self { + Self::from_le(Self::from_ne_bytes(bytes)) + } + } + + doc_comment! { + concat!("Create an integer value from its memory representation as a byte +array in native endianness. + +As the target platform's native endianness is used, portable code +likely wants to use [`from_be_bytes`] or [`from_le_bytes`], as +appropriate instead. + +[`from_be_bytes`]: #method.from_be_bytes +[`from_le_bytes`]: #method.from_le_bytes +", +$from_xe_bytes_doc, +" +# Examples + +``` +let value = ", stringify!($SelfT), "::from_ne_bytes(if cfg!(target_endian = \"big\") { + ", $be_bytes, " +} else { + ", $le_bytes, " +}); +assert_eq!(value, ", $swap_op, "); +``` + +When starting from a slice rather than an array, fallible conversion APIs can be used: + +``` +use std::convert::TryInto; + +fn read_ne_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " { + let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">()); + *input = rest; + ", stringify!($SelfT), "::from_ne_bytes(int_bytes.try_into().unwrap()) +} +```"), + #[stable(feature = "int_to_from_bytes", since = "1.32.0")] + #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")] + // SAFETY: const sound because integers are plain old datatypes so we can always + // transmute to them + #[allow_internal_unstable(const_fn_union)] + #[inline] + pub const fn from_ne_bytes(bytes: [u8; mem::size_of::<Self>()]) -> Self { + #[repr(C)] + union Bytes { + val: $SelfT, + bytes: [u8; mem::size_of::<$SelfT>()], + } + // SAFETY: integers are plain old datatypes so we can always transmute to them + unsafe { Bytes { bytes }.val } + } + } + + doc_comment! { + concat!("**This method is soft-deprecated.** + +Although using it won’t cause compilation warning, +new code should use [`", stringify!($SelfT), "::MIN", "`](#associatedconstant.MIN) instead. + +Returns the smallest value that can be represented by this integer type."), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_promotable] + #[inline(always)] + #[rustc_const_stable(feature = "const_max_value", since = "1.32.0")] + pub const fn min_value() -> Self { Self::MIN } + } + + doc_comment! { + concat!("**This method is soft-deprecated.** + +Although using it won’t cause compilation warning, +new code should use [`", stringify!($SelfT), "::MAX", "`](#associatedconstant.MAX) instead. + +Returns the largest value that can be represented by this integer type."), + #[stable(feature = "rust1", since = "1.0.0")] + #[rustc_promotable] + #[inline(always)] + #[rustc_const_stable(feature = "const_max_value", since = "1.32.0")] + pub const fn max_value() -> Self { Self::MAX } + } + } +} + +#[lang = "u8"] +impl u8 { + uint_impl! { u8, u8, 8, 255, "", "", 2, "0x82", "0xa", "0x12", "0x12", "0x48", "[0x12]", + "[0x12]", "", "" } + + /// Checks if the value is within the ASCII range. + /// + /// # Examples + /// + /// ``` + /// let ascii = 97u8; + /// let non_ascii = 150u8; + /// + /// assert!(ascii.is_ascii()); + /// assert!(!non_ascii.is_ascii()); + /// ``` + #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")] + #[rustc_const_stable(feature = "const_ascii_methods_on_intrinsics", since = "1.43.0")] + #[inline] + pub const fn is_ascii(&self) -> bool { + *self & 128 == 0 + } + + /// Makes a copy of the value in its ASCII upper case equivalent. + /// + /// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z', + /// but non-ASCII letters are unchanged. + /// + /// To uppercase the value in-place, use [`make_ascii_uppercase`]. + /// + /// # Examples + /// + /// ``` + /// let lowercase_a = 97u8; + /// + /// assert_eq!(65, lowercase_a.to_ascii_uppercase()); + /// ``` + /// + /// [`make_ascii_uppercase`]: #method.make_ascii_uppercase + #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")] + #[inline] + pub fn to_ascii_uppercase(&self) -> u8 { + // Unset the fifth bit if this is a lowercase letter + *self & !((self.is_ascii_lowercase() as u8) << 5) + } + + /// Makes a copy of the value in its ASCII lower case equivalent. + /// + /// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z', + /// but non-ASCII letters are unchanged. + /// + /// To lowercase the value in-place, use [`make_ascii_lowercase`]. + /// + /// # Examples + /// + /// ``` + /// let uppercase_a = 65u8; + /// + /// assert_eq!(97, uppercase_a.to_ascii_lowercase()); + /// ``` + /// + /// [`make_ascii_lowercase`]: #method.make_ascii_lowercase + #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")] + #[inline] + pub fn to_ascii_lowercase(&self) -> u8 { + // Set the fifth bit if this is an uppercase letter + *self | ((self.is_ascii_uppercase() as u8) << 5) + } + + /// Checks that two values are an ASCII case-insensitive match. + /// + /// This is equivalent to `to_ascii_lowercase(a) == to_ascii_lowercase(b)`. + /// + /// # Examples + /// + /// ``` + /// let lowercase_a = 97u8; + /// let uppercase_a = 65u8; + /// + /// assert!(lowercase_a.eq_ignore_ascii_case(&uppercase_a)); + /// ``` + #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")] + #[inline] + pub fn eq_ignore_ascii_case(&self, other: &u8) -> bool { + self.to_ascii_lowercase() == other.to_ascii_lowercase() + } + + /// Converts this value to its ASCII upper case equivalent in-place. + /// + /// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z', + /// but non-ASCII letters are unchanged. + /// + /// To return a new uppercased value without modifying the existing one, use + /// [`to_ascii_uppercase`]. + /// + /// # Examples + /// + /// ``` + /// let mut byte = b'a'; + /// + /// byte.make_ascii_uppercase(); + /// + /// assert_eq!(b'A', byte); + /// ``` + /// + /// [`to_ascii_uppercase`]: #method.to_ascii_uppercase + #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")] + #[inline] + pub fn make_ascii_uppercase(&mut self) { + *self = self.to_ascii_uppercase(); + } + + /// Converts this value to its ASCII lower case equivalent in-place. + /// + /// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z', + /// but non-ASCII letters are unchanged. + /// + /// To return a new lowercased value without modifying the existing one, use + /// [`to_ascii_lowercase`]. + /// + /// # Examples + /// + /// ``` + /// let mut byte = b'A'; + /// + /// byte.make_ascii_lowercase(); + /// + /// assert_eq!(b'a', byte); + /// ``` + /// + /// [`to_ascii_lowercase`]: #method.to_ascii_lowercase + #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")] + #[inline] + pub fn make_ascii_lowercase(&mut self) { + *self = self.to_ascii_lowercase(); + } + + /// Checks if the value is an ASCII alphabetic character: + /// + /// - U+0041 'A' ..= U+005A 'Z', or + /// - U+0061 'a' ..= U+007A 'z'. + /// + /// # Examples + /// + /// ``` + /// let uppercase_a = b'A'; + /// let uppercase_g = b'G'; + /// let a = b'a'; + /// let g = b'g'; + /// let zero = b'0'; + /// let percent = b'%'; + /// let space = b' '; + /// let lf = b'\n'; + /// let esc = 0x1b_u8; + /// + /// assert!(uppercase_a.is_ascii_alphabetic()); + /// assert!(uppercase_g.is_ascii_alphabetic()); + /// assert!(a.is_ascii_alphabetic()); + /// assert!(g.is_ascii_alphabetic()); + /// assert!(!zero.is_ascii_alphabetic()); + /// assert!(!percent.is_ascii_alphabetic()); + /// assert!(!space.is_ascii_alphabetic()); + /// assert!(!lf.is_ascii_alphabetic()); + /// assert!(!esc.is_ascii_alphabetic()); + /// ``` + #[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")] + #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")] + #[inline] + pub const fn is_ascii_alphabetic(&self) -> bool { + matches!(*self, b'A'..=b'Z' | b'a'..=b'z') + } + + /// Checks if the value is an ASCII uppercase character: + /// U+0041 'A' ..= U+005A 'Z'. + /// + /// # Examples + /// + /// ``` + /// let uppercase_a = b'A'; + /// let uppercase_g = b'G'; + /// let a = b'a'; + /// let g = b'g'; + /// let zero = b'0'; + /// let percent = b'%'; + /// let space = b' '; + /// let lf = b'\n'; + /// let esc = 0x1b_u8; + /// + /// assert!(uppercase_a.is_ascii_uppercase()); + /// assert!(uppercase_g.is_ascii_uppercase()); + /// assert!(!a.is_ascii_uppercase()); + /// assert!(!g.is_ascii_uppercase()); + /// assert!(!zero.is_ascii_uppercase()); + /// assert!(!percent.is_ascii_uppercase()); + /// assert!(!space.is_ascii_uppercase()); + /// assert!(!lf.is_ascii_uppercase()); + /// assert!(!esc.is_ascii_uppercase()); + /// ``` + #[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")] + #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")] + #[inline] + pub const fn is_ascii_uppercase(&self) -> bool { + matches!(*self, b'A'..=b'Z') + } + + /// Checks if the value is an ASCII lowercase character: + /// U+0061 'a' ..= U+007A 'z'. + /// + /// # Examples + /// + /// ``` + /// let uppercase_a = b'A'; + /// let uppercase_g = b'G'; + /// let a = b'a'; + /// let g = b'g'; + /// let zero = b'0'; + /// let percent = b'%'; + /// let space = b' '; + /// let lf = b'\n'; + /// let esc = 0x1b_u8; + /// + /// assert!(!uppercase_a.is_ascii_lowercase()); + /// assert!(!uppercase_g.is_ascii_lowercase()); + /// assert!(a.is_ascii_lowercase()); + /// assert!(g.is_ascii_lowercase()); + /// assert!(!zero.is_ascii_lowercase()); + /// assert!(!percent.is_ascii_lowercase()); + /// assert!(!space.is_ascii_lowercase()); + /// assert!(!lf.is_ascii_lowercase()); + /// assert!(!esc.is_ascii_lowercase()); + /// ``` + #[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")] + #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")] + #[inline] + pub const fn is_ascii_lowercase(&self) -> bool { + matches!(*self, b'a'..=b'z') + } + + /// Checks if the value is an ASCII alphanumeric character: + /// + /// - U+0041 'A' ..= U+005A 'Z', or + /// - U+0061 'a' ..= U+007A 'z', or + /// - U+0030 '0' ..= U+0039 '9'. + /// + /// # Examples + /// + /// ``` + /// let uppercase_a = b'A'; + /// let uppercase_g = b'G'; + /// let a = b'a'; + /// let g = b'g'; + /// let zero = b'0'; + /// let percent = b'%'; + /// let space = b' '; + /// let lf = b'\n'; + /// let esc = 0x1b_u8; + /// + /// assert!(uppercase_a.is_ascii_alphanumeric()); + /// assert!(uppercase_g.is_ascii_alphanumeric()); + /// assert!(a.is_ascii_alphanumeric()); + /// assert!(g.is_ascii_alphanumeric()); + /// assert!(zero.is_ascii_alphanumeric()); + /// assert!(!percent.is_ascii_alphanumeric()); + /// assert!(!space.is_ascii_alphanumeric()); + /// assert!(!lf.is_ascii_alphanumeric()); + /// assert!(!esc.is_ascii_alphanumeric()); + /// ``` + #[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")] + #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")] + #[inline] + pub const fn is_ascii_alphanumeric(&self) -> bool { + matches!(*self, b'0'..=b'9' | b'A'..=b'Z' | b'a'..=b'z') + } + + /// Checks if the value is an ASCII decimal digit: + /// U+0030 '0' ..= U+0039 '9'. + /// + /// # Examples + /// + /// ``` + /// let uppercase_a = b'A'; + /// let uppercase_g = b'G'; + /// let a = b'a'; + /// let g = b'g'; + /// let zero = b'0'; + /// let percent = b'%'; + /// let space = b' '; + /// let lf = b'\n'; + /// let esc = 0x1b_u8; + /// + /// assert!(!uppercase_a.is_ascii_digit()); + /// assert!(!uppercase_g.is_ascii_digit()); + /// assert!(!a.is_ascii_digit()); + /// assert!(!g.is_ascii_digit()); + /// assert!(zero.is_ascii_digit()); + /// assert!(!percent.is_ascii_digit()); + /// assert!(!space.is_ascii_digit()); + /// assert!(!lf.is_ascii_digit()); + /// assert!(!esc.is_ascii_digit()); + /// ``` + #[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")] + #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")] + #[inline] + pub const fn is_ascii_digit(&self) -> bool { + matches!(*self, b'0'..=b'9') + } + + /// Checks if the value is an ASCII hexadecimal digit: + /// + /// - U+0030 '0' ..= U+0039 '9', or + /// - U+0041 'A' ..= U+0046 'F', or + /// - U+0061 'a' ..= U+0066 'f'. + /// + /// # Examples + /// + /// ``` + /// let uppercase_a = b'A'; + /// let uppercase_g = b'G'; + /// let a = b'a'; + /// let g = b'g'; + /// let zero = b'0'; + /// let percent = b'%'; + /// let space = b' '; + /// let lf = b'\n'; + /// let esc = 0x1b_u8; + /// + /// assert!(uppercase_a.is_ascii_hexdigit()); + /// assert!(!uppercase_g.is_ascii_hexdigit()); + /// assert!(a.is_ascii_hexdigit()); + /// assert!(!g.is_ascii_hexdigit()); + /// assert!(zero.is_ascii_hexdigit()); + /// assert!(!percent.is_ascii_hexdigit()); + /// assert!(!space.is_ascii_hexdigit()); + /// assert!(!lf.is_ascii_hexdigit()); + /// assert!(!esc.is_ascii_hexdigit()); + /// ``` + #[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")] + #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")] + #[inline] + pub const fn is_ascii_hexdigit(&self) -> bool { + matches!(*self, b'0'..=b'9' | b'A'..=b'F' | b'a'..=b'f') + } + + /// Checks if the value is an ASCII punctuation character: + /// + /// - U+0021 ..= U+002F `! " # $ % & ' ( ) * + , - . /`, or + /// - U+003A ..= U+0040 `: ; < = > ? @`, or + /// - U+005B ..= U+0060 ``[ \ ] ^ _ ` ``, or + /// - U+007B ..= U+007E `{ | } ~` + /// + /// # Examples + /// + /// ``` + /// let uppercase_a = b'A'; + /// let uppercase_g = b'G'; + /// let a = b'a'; + /// let g = b'g'; + /// let zero = b'0'; + /// let percent = b'%'; + /// let space = b' '; + /// let lf = b'\n'; + /// let esc = 0x1b_u8; + /// + /// assert!(!uppercase_a.is_ascii_punctuation()); + /// assert!(!uppercase_g.is_ascii_punctuation()); + /// assert!(!a.is_ascii_punctuation()); + /// assert!(!g.is_ascii_punctuation()); + /// assert!(!zero.is_ascii_punctuation()); + /// assert!(percent.is_ascii_punctuation()); + /// assert!(!space.is_ascii_punctuation()); + /// assert!(!lf.is_ascii_punctuation()); + /// assert!(!esc.is_ascii_punctuation()); + /// ``` + #[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")] + #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")] + #[inline] + pub const fn is_ascii_punctuation(&self) -> bool { + matches!(*self, b'!'..=b'/' | b':'..=b'@' | b'['..=b'`' | b'{'..=b'~') + } + + /// Checks if the value is an ASCII graphic character: + /// U+0021 '!' ..= U+007E '~'. + /// + /// # Examples + /// + /// ``` + /// let uppercase_a = b'A'; + /// let uppercase_g = b'G'; + /// let a = b'a'; + /// let g = b'g'; + /// let zero = b'0'; + /// let percent = b'%'; + /// let space = b' '; + /// let lf = b'\n'; + /// let esc = 0x1b_u8; + /// + /// assert!(uppercase_a.is_ascii_graphic()); + /// assert!(uppercase_g.is_ascii_graphic()); + /// assert!(a.is_ascii_graphic()); + /// assert!(g.is_ascii_graphic()); + /// assert!(zero.is_ascii_graphic()); + /// assert!(percent.is_ascii_graphic()); + /// assert!(!space.is_ascii_graphic()); + /// assert!(!lf.is_ascii_graphic()); + /// assert!(!esc.is_ascii_graphic()); + /// ``` + #[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")] + #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")] + #[inline] + pub const fn is_ascii_graphic(&self) -> bool { + matches!(*self, b'!'..=b'~') + } + + /// Checks if the value is an ASCII whitespace character: + /// U+0020 SPACE, U+0009 HORIZONTAL TAB, U+000A LINE FEED, + /// U+000C FORM FEED, or U+000D CARRIAGE RETURN. + /// + /// Rust uses the WhatWG Infra Standard's [definition of ASCII + /// whitespace][infra-aw]. There are several other definitions in + /// wide use. For instance, [the POSIX locale][pct] includes + /// U+000B VERTICAL TAB as well as all the above characters, + /// but—from the very same specification—[the default rule for + /// "field splitting" in the Bourne shell][bfs] considers *only* + /// SPACE, HORIZONTAL TAB, and LINE FEED as whitespace. + /// + /// If you are writing a program that will process an existing + /// file format, check what that format's definition of whitespace is + /// before using this function. + /// + /// [infra-aw]: https://infra.spec.whatwg.org/#ascii-whitespace + /// [pct]: http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap07.html#tag_07_03_01 + /// [bfs]: http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_05 + /// + /// # Examples + /// + /// ``` + /// let uppercase_a = b'A'; + /// let uppercase_g = b'G'; + /// let a = b'a'; + /// let g = b'g'; + /// let zero = b'0'; + /// let percent = b'%'; + /// let space = b' '; + /// let lf = b'\n'; + /// let esc = 0x1b_u8; + /// + /// assert!(!uppercase_a.is_ascii_whitespace()); + /// assert!(!uppercase_g.is_ascii_whitespace()); + /// assert!(!a.is_ascii_whitespace()); + /// assert!(!g.is_ascii_whitespace()); + /// assert!(!zero.is_ascii_whitespace()); + /// assert!(!percent.is_ascii_whitespace()); + /// assert!(space.is_ascii_whitespace()); + /// assert!(lf.is_ascii_whitespace()); + /// assert!(!esc.is_ascii_whitespace()); + /// ``` + #[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")] + #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")] + #[inline] + pub const fn is_ascii_whitespace(&self) -> bool { + matches!(*self, b'\t' | b'\n' | b'\x0C' | b'\r' | b' ') + } + + /// Checks if the value is an ASCII control character: + /// U+0000 NUL ..= U+001F UNIT SEPARATOR, or U+007F DELETE. + /// Note that most ASCII whitespace characters are control + /// characters, but SPACE is not. + /// + /// # Examples + /// + /// ``` + /// let uppercase_a = b'A'; + /// let uppercase_g = b'G'; + /// let a = b'a'; + /// let g = b'g'; + /// let zero = b'0'; + /// let percent = b'%'; + /// let space = b' '; + /// let lf = b'\n'; + /// let esc = 0x1b_u8; + /// + /// assert!(!uppercase_a.is_ascii_control()); + /// assert!(!uppercase_g.is_ascii_control()); + /// assert!(!a.is_ascii_control()); + /// assert!(!g.is_ascii_control()); + /// assert!(!zero.is_ascii_control()); + /// assert!(!percent.is_ascii_control()); + /// assert!(!space.is_ascii_control()); + /// assert!(lf.is_ascii_control()); + /// assert!(esc.is_ascii_control()); + /// ``` + #[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")] + #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")] + #[inline] + pub const fn is_ascii_control(&self) -> bool { + matches!(*self, b'\0'..=b'\x1F' | b'\x7F') + } +} + +#[lang = "u16"] +impl u16 { + uint_impl! { u16, u16, 16, 65535, "", "", 4, "0xa003", "0x3a", "0x1234", "0x3412", "0x2c48", + "[0x34, 0x12]", "[0x12, 0x34]", "", "" } +} + +#[lang = "u32"] +impl u32 { + uint_impl! { u32, u32, 32, 4294967295, "", "", 8, "0x10000b3", "0xb301", "0x12345678", + "0x78563412", "0x1e6a2c48", "[0x78, 0x56, 0x34, 0x12]", "[0x12, 0x34, 0x56, 0x78]", "", "" } +} + +#[lang = "u64"] +impl u64 { + uint_impl! { u64, u64, 64, 18446744073709551615, "", "", 12, "0xaa00000000006e1", "0x6e10aa", + "0x1234567890123456", "0x5634129078563412", "0x6a2c48091e6a2c48", + "[0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]", + "[0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56]", + "", ""} +} + +#[lang = "u128"] +impl u128 { + uint_impl! { u128, u128, 128, 340282366920938463463374607431768211455, "", "", 16, + "0x13f40000000000000000000000004f76", "0x4f7613f4", "0x12345678901234567890123456789012", + "0x12907856341290785634129078563412", "0x48091e6a2c48091e6a2c48091e6a2c48", + "[0x12, 0x90, 0x78, 0x56, 0x34, 0x12, 0x90, 0x78, \ + 0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]", + "[0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56, \ + 0x78, 0x90, 0x12, 0x34, 0x56, 0x78, 0x90, 0x12]", + "", ""} +} + +#[cfg(target_pointer_width = "16")] +#[lang = "usize"] +impl usize { + uint_impl! { usize, u16, 16, 65535, "", "", 4, "0xa003", "0x3a", "0x1234", "0x3412", "0x2c48", + "[0x34, 0x12]", "[0x12, 0x34]", + usize_isize_to_xe_bytes_doc!(), usize_isize_from_xe_bytes_doc!() } +} +#[cfg(target_pointer_width = "32")] +#[lang = "usize"] +impl usize { + uint_impl! { usize, u32, 32, 4294967295, "", "", 8, "0x10000b3", "0xb301", "0x12345678", + "0x78563412", "0x1e6a2c48", "[0x78, 0x56, 0x34, 0x12]", "[0x12, 0x34, 0x56, 0x78]", + usize_isize_to_xe_bytes_doc!(), usize_isize_from_xe_bytes_doc!() } +} + +#[cfg(target_pointer_width = "64")] +#[lang = "usize"] +impl usize { + uint_impl! { usize, u64, 64, 18446744073709551615, "", "", 12, "0xaa00000000006e1", "0x6e10aa", + "0x1234567890123456", "0x5634129078563412", "0x6a2c48091e6a2c48", + "[0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]", + "[0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56]", + usize_isize_to_xe_bytes_doc!(), usize_isize_from_xe_bytes_doc!() } +} + +/// A classification of floating point numbers. +/// +/// This `enum` is used as the return type for [`f32::classify`] and [`f64::classify`]. See +/// their documentation for more. +/// +/// [`f32::classify`]: ../../std/primitive.f32.html#method.classify +/// [`f64::classify`]: ../../std/primitive.f64.html#method.classify +/// +/// # Examples +/// +/// ``` +/// use std::num::FpCategory; +/// +/// let num = 12.4_f32; +/// let inf = f32::INFINITY; +/// let zero = 0f32; +/// let sub: f32 = 1.1754942e-38; +/// let nan = f32::NAN; +/// +/// assert_eq!(num.classify(), FpCategory::Normal); +/// assert_eq!(inf.classify(), FpCategory::Infinite); +/// assert_eq!(zero.classify(), FpCategory::Zero); +/// assert_eq!(nan.classify(), FpCategory::Nan); +/// assert_eq!(sub.classify(), FpCategory::Subnormal); +/// ``` +#[derive(Copy, Clone, PartialEq, Eq, Debug)] +#[stable(feature = "rust1", since = "1.0.0")] +pub enum FpCategory { + /// "Not a Number", often obtained by dividing by zero. + #[stable(feature = "rust1", since = "1.0.0")] + Nan, + + /// Positive or negative infinity. + #[stable(feature = "rust1", since = "1.0.0")] + Infinite, + + /// Positive or negative zero. + #[stable(feature = "rust1", since = "1.0.0")] + Zero, + + /// De-normalized floating point representation (less precise than `Normal`). + #[stable(feature = "rust1", since = "1.0.0")] + Subnormal, + + /// A regular floating point number. + #[stable(feature = "rust1", since = "1.0.0")] + Normal, +} + +macro_rules! from_str_radix_int_impl { + ($($t:ty)*) => {$( + #[stable(feature = "rust1", since = "1.0.0")] + impl FromStr for $t { + type Err = ParseIntError; + fn from_str(src: &str) -> Result<Self, ParseIntError> { + from_str_radix(src, 10) + } + } + )*} +} +from_str_radix_int_impl! { isize i8 i16 i32 i64 i128 usize u8 u16 u32 u64 u128 } + +/// The error type returned when a checked integral type conversion fails. +#[stable(feature = "try_from", since = "1.34.0")] +#[derive(Debug, Copy, Clone, PartialEq, Eq)] +pub struct TryFromIntError(pub(crate) ()); + +impl TryFromIntError { + #[unstable( + feature = "int_error_internals", + reason = "available through Error trait and this method should \ + not be exposed publicly", + issue = "none" + )] + #[doc(hidden)] + pub fn __description(&self) -> &str { + "out of range integral type conversion attempted" + } +} + +#[stable(feature = "try_from", since = "1.34.0")] +impl fmt::Display for TryFromIntError { + fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result { + self.__description().fmt(fmt) + } +} + +#[stable(feature = "try_from", since = "1.34.0")] +impl From<Infallible> for TryFromIntError { + fn from(x: Infallible) -> TryFromIntError { + match x {} + } +} + +#[unstable(feature = "never_type", issue = "35121")] +impl From<!> for TryFromIntError { + fn from(never: !) -> TryFromIntError { + // Match rather than coerce to make sure that code like + // `From<Infallible> for TryFromIntError` above will keep working + // when `Infallible` becomes an alias to `!`. + match never {} + } +} + +#[doc(hidden)] +trait FromStrRadixHelper: PartialOrd + Copy { + fn min_value() -> Self; + fn max_value() -> Self; + fn from_u32(u: u32) -> Self; + fn checked_mul(&self, other: u32) -> Option<Self>; + fn checked_sub(&self, other: u32) -> Option<Self>; + fn checked_add(&self, other: u32) -> Option<Self>; +} + +macro_rules! doit { + ($($t:ty)*) => ($(impl FromStrRadixHelper for $t { + #[inline] + fn min_value() -> Self { Self::MIN } + #[inline] + fn max_value() -> Self { Self::MAX } + #[inline] + fn from_u32(u: u32) -> Self { u as Self } + #[inline] + fn checked_mul(&self, other: u32) -> Option<Self> { + Self::checked_mul(*self, other as Self) + } + #[inline] + fn checked_sub(&self, other: u32) -> Option<Self> { + Self::checked_sub(*self, other as Self) + } + #[inline] + fn checked_add(&self, other: u32) -> Option<Self> { + Self::checked_add(*self, other as Self) + } + })*) +} +doit! { i8 i16 i32 i64 i128 isize u8 u16 u32 u64 u128 usize } + +fn from_str_radix<T: FromStrRadixHelper>(src: &str, radix: u32) -> Result<T, ParseIntError> { + use self::IntErrorKind::*; + use self::ParseIntError as PIE; + + assert!( + radix >= 2 && radix <= 36, + "from_str_radix_int: must lie in the range `[2, 36]` - found {}", + radix + ); + + if src.is_empty() { + return Err(PIE { kind: Empty }); + } + + let is_signed_ty = T::from_u32(0) > T::min_value(); + + // all valid digits are ascii, so we will just iterate over the utf8 bytes + // and cast them to chars. .to_digit() will safely return None for anything + // other than a valid ascii digit for the given radix, including the first-byte + // of multi-byte sequences + let src = src.as_bytes(); + + let (is_positive, digits) = match src[0] { + b'+' => (true, &src[1..]), + b'-' if is_signed_ty => (false, &src[1..]), + _ => (true, src), + }; + + if digits.is_empty() { + return Err(PIE { kind: Empty }); + } + + let mut result = T::from_u32(0); + if is_positive { + // The number is positive + for &c in digits { + let x = match (c as char).to_digit(radix) { + Some(x) => x, + None => return Err(PIE { kind: InvalidDigit }), + }; + result = match result.checked_mul(radix) { + Some(result) => result, + None => return Err(PIE { kind: Overflow }), + }; + result = match result.checked_add(x) { + Some(result) => result, + None => return Err(PIE { kind: Overflow }), + }; + } + } else { + // The number is negative + for &c in digits { + let x = match (c as char).to_digit(radix) { + Some(x) => x, + None => return Err(PIE { kind: InvalidDigit }), + }; + result = match result.checked_mul(radix) { + Some(result) => result, + None => return Err(PIE { kind: Underflow }), + }; + result = match result.checked_sub(x) { + Some(result) => result, + None => return Err(PIE { kind: Underflow }), + }; + } + } + Ok(result) +} + +/// An error which can be returned when parsing an integer. +/// +/// This error is used as the error type for the `from_str_radix()` functions +/// on the primitive integer types, such as [`i8::from_str_radix`]. +/// +/// # Potential causes +/// +/// Among other causes, `ParseIntError` can be thrown because of leading or trailing whitespace +/// in the string e.g., when it is obtained from the standard input. +/// Using the [`str.trim()`] method ensures that no whitespace remains before parsing. +/// +/// [`str.trim()`]: ../../std/primitive.str.html#method.trim +/// [`i8::from_str_radix`]: ../../std/primitive.i8.html#method.from_str_radix +#[derive(Debug, Clone, PartialEq, Eq)] +#[stable(feature = "rust1", since = "1.0.0")] +pub struct ParseIntError { + kind: IntErrorKind, +} + +/// Enum to store the various types of errors that can cause parsing an integer to fail. +#[unstable( + feature = "int_error_matching", + reason = "it can be useful to match errors when making error messages \ + for integer parsing", + issue = "22639" +)] +#[derive(Debug, Clone, PartialEq, Eq)] +#[non_exhaustive] +pub enum IntErrorKind { + /// Value being parsed is empty. + /// + /// Among other causes, this variant will be constructed when parsing an empty string. + Empty, + /// Contains an invalid digit. + /// + /// Among other causes, this variant will be constructed when parsing a string that + /// contains a letter. + InvalidDigit, + /// Integer is too large to store in target integer type. + Overflow, + /// Integer is too small to store in target integer type. + Underflow, + /// Value was Zero + /// + /// This variant will be emitted when the parsing string has a value of zero, which + /// would be illegal for non-zero types. + Zero, +} + +impl ParseIntError { + /// Outputs the detailed cause of parsing an integer failing. + #[unstable( + feature = "int_error_matching", + reason = "it can be useful to match errors when making error messages \ + for integer parsing", + issue = "22639" + )] + pub fn kind(&self) -> &IntErrorKind { + &self.kind + } + #[unstable( + feature = "int_error_internals", + reason = "available through Error trait and this method should \ + not be exposed publicly", + issue = "none" + )] + #[doc(hidden)] + pub fn __description(&self) -> &str { + match self.kind { + IntErrorKind::Empty => "cannot parse integer from empty string", + IntErrorKind::InvalidDigit => "invalid digit found in string", + IntErrorKind::Overflow => "number too large to fit in target type", + IntErrorKind::Underflow => "number too small to fit in target type", + IntErrorKind::Zero => "number would be zero for non-zero type", + } + } +} + +#[stable(feature = "rust1", since = "1.0.0")] +impl fmt::Display for ParseIntError { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.__description().fmt(f) + } +} + +#[stable(feature = "rust1", since = "1.0.0")] +pub use crate::num::dec2flt::ParseFloatError; 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