macro_rules! uint_impl { ( Self = $SelfT:ty, ActualT = $ActualT:ident, SignedT = $SignedT:ident, NonZeroT = $NonZeroT:ident, // There are all for use *only* in doc comments. // As such, they're all passed as literals -- passing them as a string // literal is fine if they need to be multiple code tokens. // In non-comments, use the associated constants rather than these. BITS = $BITS:literal, MAX = $MaxV:literal, rot = $rot:literal, rot_op = $rot_op:literal, rot_result = $rot_result:literal, swap_op = $swap_op:literal, swapped = $swapped:literal, reversed = $reversed:literal, le_bytes = $le_bytes:literal, be_bytes = $be_bytes:literal, to_xe_bytes_doc = $to_xe_bytes_doc:expr, from_xe_bytes_doc = $from_xe_bytes_doc:expr, bound_condition = $bound_condition:literal, ) => { /// The smallest value that can be represented by this integer type. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN, 0);")] /// ``` #[stable(feature = "assoc_int_consts", since = "1.43.0")] pub const MIN: Self = 0; /// The largest value that can be represented by this integer type #[doc = concat!("(2^{", $BITS, "} − 1", $bound_condition, ").")] /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX, ", stringify!($MaxV), ");")] /// ``` #[stable(feature = "assoc_int_consts", since = "1.43.0")] pub const MAX: Self = !0; /// The size of this integer type in bits. /// /// # Examples /// /// ``` #[doc = concat!("assert_eq!(", stringify!($SelfT), "::BITS, ", stringify!($BITS), ");")] /// ``` #[stable(feature = "int_bits_const", since = "1.53.0")] pub const BITS: u32 = Self::MAX.count_ones(); /// Converts a string slice in a given base to an integer. /// /// The string is expected to be an optional `+` sign /// followed by digits. /// Leading and trailing whitespace represent an error. /// Digits are a subset of these characters, depending on `radix`: /// /// * `0-9` /// * `a-z` /// * `A-Z` /// /// # Panics /// /// This function panics if `radix` is not in the range from 2 to 36. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(", stringify!($SelfT), "::from_str_radix(\"A\", 16), Ok(10));")] /// ``` #[stable(feature = "rust1", since = "1.0.0")] pub fn from_str_radix(src: &str, radix: u32) -> Result { from_str_radix(src, radix) } /// Returns the number of ones in the binary representation of `self`. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("let n = 0b01001100", stringify!($SelfT), ";")] /// /// assert_eq!(n.count_ones(), 3); /// ``` #[stable(feature = "rust1", since = "1.0.0")] #[rustc_const_stable(feature = "const_math", since = "1.32.0")] #[doc(alias = "popcount")] #[doc(alias = "popcnt")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline(always)] pub const fn count_ones(self) -> u32 { intrinsics::ctpop(self as $ActualT) as u32 } /// Returns the number of zeros in the binary representation of `self`. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.count_zeros(), 0);")] /// ``` #[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(always)] pub const fn count_zeros(self) -> u32 { (!self).count_ones() } /// Returns the number of leading zeros in the binary representation of `self`. /// /// Depending on what you're doing with the value, you might also be interested in the /// [`ilog2`] function which returns a consistent number, even if the type widens. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("let n = ", stringify!($SelfT), "::MAX >> 2;")] /// /// assert_eq!(n.leading_zeros(), 2); /// ``` #[doc = concat!("[`ilog2`]: ", stringify!($SelfT), "::ilog2")] #[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(always)] pub const fn leading_zeros(self) -> u32 { intrinsics::ctlz(self as $ActualT) as u32 } /// Returns the number of trailing zeros in the binary representation /// of `self`. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("let n = 0b0101000", stringify!($SelfT), ";")] /// /// assert_eq!(n.trailing_zeros(), 3); /// ``` #[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(always)] pub const fn trailing_zeros(self) -> u32 { intrinsics::cttz(self) as u32 } /// Returns the number of leading ones in the binary representation of `self`. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("let n = !(", stringify!($SelfT), "::MAX >> 2);")] /// /// assert_eq!(n.leading_ones(), 2); /// ``` #[stable(feature = "leading_trailing_ones", since = "1.46.0")] #[rustc_const_stable(feature = "leading_trailing_ones", since = "1.46.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline(always)] pub const fn leading_ones(self) -> u32 { (!self).leading_zeros() } /// Returns the number of trailing ones in the binary representation /// of `self`. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("let n = 0b1010111", stringify!($SelfT), ";")] /// /// assert_eq!(n.trailing_ones(), 3); /// ``` #[stable(feature = "leading_trailing_ones", since = "1.46.0")] #[rustc_const_stable(feature = "leading_trailing_ones", since = "1.46.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline(always)] pub const fn trailing_ones(self) -> u32 { (!self).trailing_zeros() } /// 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: /// /// ``` #[doc = concat!("let n = ", $rot_op, stringify!($SelfT), ";")] #[doc = concat!("let m = ", $rot_result, ";")] /// #[doc = concat!("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(always)] pub const fn rotate_left(self, n: u32) -> Self { intrinsics::rotate_left(self, n as $SelfT) } /// 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: /// /// ``` #[doc = concat!("let n = ", $rot_result, stringify!($SelfT), ";")] #[doc = concat!("let m = ", $rot_op, ";")] /// #[doc = concat!("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(always)] pub const fn rotate_right(self, n: u32) -> Self { intrinsics::rotate_right(self, n as $SelfT) } /// Reverses the byte order of the integer. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("let n = ", $swap_op, stringify!($SelfT), ";")] /// let m = n.swap_bytes(); /// #[doc = concat!("assert_eq!(m, ", $swapped, ");")] /// ``` #[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(always)] pub const fn swap_bytes(self) -> Self { intrinsics::bswap(self as $ActualT) as Self } /// Reverses the order of bits in the integer. The least significant bit becomes the most significant bit, /// second least-significant bit becomes second most-significant bit, etc. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("let n = ", $swap_op, stringify!($SelfT), ";")] /// let m = n.reverse_bits(); /// #[doc = concat!("assert_eq!(m, ", $reversed, ");")] #[doc = concat!("assert_eq!(0, 0", stringify!($SelfT), ".reverse_bits());")] /// ``` #[stable(feature = "reverse_bits", since = "1.37.0")] #[rustc_const_stable(feature = "reverse_bits", since = "1.37.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline(always)] pub const fn reverse_bits(self) -> Self { intrinsics::bitreverse(self as $ActualT) as Self } /// Converts an integer from big endian to the target's endianness. /// /// On big endian this is a no-op. On little endian the bytes are /// swapped. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")] /// /// if cfg!(target_endian = "big") { #[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_be(n), n)")] /// } else { #[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_be(n), n.swap_bytes())")] /// } /// ``` #[stable(feature = "rust1", since = "1.0.0")] #[rustc_const_stable(feature = "const_math", since = "1.32.0")] #[must_use] #[inline(always)] pub const fn from_be(x: Self) -> Self { #[cfg(target_endian = "big")] { x } #[cfg(not(target_endian = "big"))] { x.swap_bytes() } } /// 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: /// /// ``` #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")] /// /// if cfg!(target_endian = "little") { #[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_le(n), n)")] /// } else { #[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_le(n), n.swap_bytes())")] /// } /// ``` #[stable(feature = "rust1", since = "1.0.0")] #[rustc_const_stable(feature = "const_math", since = "1.32.0")] #[must_use] #[inline(always)] pub const fn from_le(x: Self) -> Self { #[cfg(target_endian = "little")] { x } #[cfg(not(target_endian = "little"))] { x.swap_bytes() } } /// Converts `self` to big endian from the target's endianness. /// /// On big endian this is a no-op. On little endian the bytes are /// swapped. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")] /// /// if cfg!(target_endian = "big") { /// assert_eq!(n.to_be(), n) /// } else { /// assert_eq!(n.to_be(), n.swap_bytes()) /// } /// ``` #[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(always)] pub const fn to_be(self) -> Self { // or not to be? #[cfg(target_endian = "big")] { self } #[cfg(not(target_endian = "big"))] { self.swap_bytes() } } /// 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: /// /// ``` #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")] /// /// if cfg!(target_endian = "little") { /// assert_eq!(n.to_le(), n) /// } else { /// assert_eq!(n.to_le(), n.swap_bytes()) /// } /// ``` #[stable(feature = "rust1", since = "1.0.0")] #[rustc_const_stable(feature = "const_math", since = "1.32.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline(always)] pub const fn to_le(self) -> Self { #[cfg(target_endian = "little")] { self } #[cfg(not(target_endian = "little"))] { self.swap_bytes() } } /// Checked integer addition. Computes `self + rhs`, returning `None` /// if overflow occurred. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!( "assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add(1), ", "Some(", stringify!($SelfT), "::MAX - 1));" )] #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add(3), None);")] /// ``` #[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 { let (a, b) = self.overflowing_add(rhs); if unlikely!(b) {None} else {Some(a)} } /// Unchecked integer addition. Computes `self + rhs`, assuming overflow /// cannot occur. /// /// # Safety /// /// This results in undefined behavior when #[doc = concat!("`self + rhs > ", stringify!($SelfT), "::MAX` or `self + rhs < ", stringify!($SelfT), "::MIN`,")] /// i.e. when [`checked_add`] would return `None`. /// #[doc = concat!("[`checked_add`]: ", stringify!($SelfT), "::checked_add")] #[unstable( feature = "unchecked_math", reason = "niche optimization path", issue = "85122", )] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[rustc_const_unstable(feature = "const_inherent_unchecked_arith", issue = "85122")] #[inline(always)] #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces pub const unsafe fn unchecked_add(self, rhs: Self) -> Self { // SAFETY: the caller must uphold the safety contract for // `unchecked_add`. unsafe { intrinsics::unchecked_add(self, rhs) } } /// Checked addition with a signed integer. Computes `self + rhs`, /// returning `None` if overflow occurred. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_add_signed(2), Some(3));")] #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_add_signed(-2), None);")] #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add_signed(3), None);")] /// ``` #[stable(feature = "mixed_integer_ops", since = "1.66.0")] #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] pub const fn checked_add_signed(self, rhs: $SignedT) -> Option { let (a, b) = self.overflowing_add_signed(rhs); if unlikely!(b) {None} else {Some(a)} } /// Checked integer subtraction. Computes `self - rhs`, returning /// `None` if overflow occurred. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_sub(1), Some(0));")] #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".checked_sub(1), None);")] /// ``` #[stable(feature = "rust1", since = "1.0.0")] #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] pub const fn checked_sub(self, rhs: Self) -> Option { let (a, b) = self.overflowing_sub(rhs); if unlikely!(b) {None} else {Some(a)} } /// Unchecked integer subtraction. Computes `self - rhs`, assuming overflow /// cannot occur. /// /// # Safety /// /// This results in undefined behavior when #[doc = concat!("`self - rhs > ", stringify!($SelfT), "::MAX` or `self - rhs < ", stringify!($SelfT), "::MIN`,")] /// i.e. when [`checked_sub`] would return `None`. /// #[doc = concat!("[`checked_sub`]: ", stringify!($SelfT), "::checked_sub")] #[unstable( feature = "unchecked_math", reason = "niche optimization path", issue = "85122", )] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[rustc_const_unstable(feature = "const_inherent_unchecked_arith", issue = "85122")] #[inline(always)] #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces pub const 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) } } /// Checked integer multiplication. Computes `self * rhs`, returning /// `None` if overflow occurred. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_mul(1), Some(5));")] #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_mul(2), None);")] /// ``` #[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 { let (a, b) = self.overflowing_mul(rhs); if unlikely!(b) {None} else {Some(a)} } /// Unchecked integer multiplication. Computes `self * rhs`, assuming overflow /// cannot occur. /// /// # Safety /// /// This results in undefined behavior when #[doc = concat!("`self * rhs > ", stringify!($SelfT), "::MAX` or `self * rhs < ", stringify!($SelfT), "::MIN`,")] /// i.e. when [`checked_mul`] would return `None`. /// #[doc = concat!("[`checked_mul`]: ", stringify!($SelfT), "::checked_mul")] #[unstable( feature = "unchecked_math", reason = "niche optimization path", issue = "85122", )] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[rustc_const_unstable(feature = "const_inherent_unchecked_arith", issue = "85122")] #[inline(always)] #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces pub const unsafe fn unchecked_mul(self, rhs: Self) -> Self { // SAFETY: the caller must uphold the safety contract for // `unchecked_mul`. unsafe { intrinsics::unchecked_mul(self, rhs) } } /// Checked integer division. Computes `self / rhs`, returning `None` /// if `rhs == 0`. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(128", stringify!($SelfT), ".checked_div(2), Some(64));")] #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_div(0), None);")] /// ``` #[stable(feature = "rust1", since = "1.0.0")] #[rustc_const_stable(feature = "const_checked_int_div", since = "1.52.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] pub const fn checked_div(self, rhs: Self) -> Option { if unlikely!(rhs == 0) { None } else { // SAFETY: div by zero has been checked above and unsigned types have no other // failure modes for division Some(unsafe { intrinsics::unchecked_div(self, rhs) }) } } /// Checked Euclidean division. Computes `self.div_euclid(rhs)`, returning `None` /// if `rhs == 0`. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(128", stringify!($SelfT), ".checked_div_euclid(2), Some(64));")] #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_div_euclid(0), None);")] /// ``` #[stable(feature = "euclidean_division", since = "1.38.0")] #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] pub const fn checked_div_euclid(self, rhs: Self) -> Option { if unlikely!(rhs == 0) { None } else { Some(self.div_euclid(rhs)) } } /// Checked integer remainder. Computes `self % rhs`, returning `None` /// if `rhs == 0`. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem(2), Some(1));")] #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem(0), None);")] /// ``` #[stable(feature = "wrapping", since = "1.7.0")] #[rustc_const_stable(feature = "const_checked_int_div", since = "1.52.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] pub const fn checked_rem(self, rhs: Self) -> Option { if unlikely!(rhs == 0) { None } else { // SAFETY: div by zero has been checked above and unsigned types have no other // failure modes for division Some(unsafe { intrinsics::unchecked_rem(self, rhs) }) } } /// Checked Euclidean modulo. Computes `self.rem_euclid(rhs)`, returning `None` /// if `rhs == 0`. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(2), Some(1));")] #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(0), None);")] /// ``` #[stable(feature = "euclidean_division", since = "1.38.0")] #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] pub const fn checked_rem_euclid(self, rhs: Self) -> Option { if unlikely!(rhs == 0) { None } else { Some(self.rem_euclid(rhs)) } } /// Returns the logarithm of the number with respect to an arbitrary base, /// rounded down. /// /// This method might not be optimized owing to implementation details; /// `ilog2` can produce results more efficiently for base 2, and `ilog10` /// can produce results more efficiently for base 10. /// /// # Panics /// /// This function will panic if `self` is zero, or if `base` is less than 2. /// /// # Examples /// /// ``` #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".ilog(5), 1);")] /// ``` #[stable(feature = "int_log", since = "1.67.0")] #[rustc_const_stable(feature = "int_log", since = "1.67.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] #[track_caller] pub const fn ilog(self, base: Self) -> u32 { assert!(base >= 2, "base of integer logarithm must be at least 2"); if let Some(log) = self.checked_ilog(base) { log } else { int_log10::panic_for_nonpositive_argument() } } /// Returns the base 2 logarithm of the number, rounded down. /// /// # Panics /// /// This function will panic if `self` is zero. /// /// # Examples /// /// ``` #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".ilog2(), 1);")] /// ``` #[stable(feature = "int_log", since = "1.67.0")] #[rustc_const_stable(feature = "int_log", since = "1.67.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] #[track_caller] pub const fn ilog2(self) -> u32 { if let Some(log) = self.checked_ilog2() { log } else { int_log10::panic_for_nonpositive_argument() } } /// Returns the base 10 logarithm of the number, rounded down. /// /// # Panics /// /// This function will panic if `self` is zero. /// /// # Example /// /// ``` #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".ilog10(), 1);")] /// ``` #[stable(feature = "int_log", since = "1.67.0")] #[rustc_const_stable(feature = "int_log", since = "1.67.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] #[track_caller] pub const fn ilog10(self) -> u32 { if let Some(log) = self.checked_ilog10() { log } else { int_log10::panic_for_nonpositive_argument() } } /// Returns the logarithm of the number with respect to an arbitrary base, /// rounded down. /// /// Returns `None` if the number is zero, or if the base is not at least 2. /// /// This method might not be optimized owing to implementation details; /// `checked_ilog2` can produce results more efficiently for base 2, and /// `checked_ilog10` can produce results more efficiently for base 10. /// /// # Examples /// /// ``` #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_ilog(5), Some(1));")] /// ``` #[stable(feature = "int_log", since = "1.67.0")] #[rustc_const_stable(feature = "int_log", since = "1.67.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] pub const fn checked_ilog(self, base: Self) -> Option { if self <= 0 || base <= 1 { None } else { let mut n = 0; let mut r = self; // Optimization for 128 bit wide integers. if Self::BITS == 128 { let b = Self::ilog2(self) / (Self::ilog2(base) + 1); n += b; r /= base.pow(b as u32); } while r >= base { r /= base; n += 1; } Some(n) } } /// Returns the base 2 logarithm of the number, rounded down. /// /// Returns `None` if the number is zero. /// /// # Examples /// /// ``` #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_ilog2(), Some(1));")] /// ``` #[stable(feature = "int_log", since = "1.67.0")] #[rustc_const_stable(feature = "int_log", since = "1.67.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] pub const fn checked_ilog2(self) -> Option { if let Some(x) = <$NonZeroT>::new(self) { Some(x.ilog2()) } else { None } } /// Returns the base 10 logarithm of the number, rounded down. /// /// Returns `None` if the number is zero. /// /// # Examples /// /// ``` #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".checked_ilog10(), Some(1));")] /// ``` #[stable(feature = "int_log", since = "1.67.0")] #[rustc_const_stable(feature = "int_log", since = "1.67.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] pub const fn checked_ilog10(self) -> Option { if let Some(x) = <$NonZeroT>::new(self) { Some(x.ilog10()) } else { None } } /// Checked negation. Computes `-self`, returning `None` unless `self == /// 0`. /// /// Note that negating any positive integer will overflow. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".checked_neg(), Some(0));")] #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_neg(), None);")] /// ``` #[stable(feature = "wrapping", since = "1.7.0")] #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] pub const fn checked_neg(self) -> Option { let (a, b) = self.overflowing_neg(); if unlikely!(b) {None} else {Some(a)} } /// Checked shift left. Computes `self << rhs`, returning `None` /// if `rhs` is larger than or equal to the number of bits in `self`. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".checked_shl(4), Some(0x10));")] #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shl(129), None);")] /// ``` #[stable(feature = "wrapping", since = "1.7.0")] #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] pub const fn checked_shl(self, rhs: u32) -> Option { let (a, b) = self.overflowing_shl(rhs); if unlikely!(b) {None} else {Some(a)} } /// Unchecked shift left. Computes `self << rhs`, assuming that /// `rhs` is less than the number of bits in `self`. /// /// # Safety /// /// This results in undefined behavior if `rhs` is larger than /// or equal to the number of bits in `self`, /// i.e. when [`checked_shl`] would return `None`. /// #[doc = concat!("[`checked_shl`]: ", stringify!($SelfT), "::checked_shl")] #[unstable( feature = "unchecked_math", reason = "niche optimization path", issue = "85122", )] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[rustc_const_unstable(feature = "const_inherent_unchecked_arith", issue = "85122")] #[inline(always)] #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces pub const unsafe fn unchecked_shl(self, rhs: u32) -> Self { // SAFETY: the caller must uphold the safety contract for // `unchecked_shl`. // Any legal shift amount is losslessly representable in the self type. unsafe { intrinsics::unchecked_shl(self, rhs.try_into().ok().unwrap_unchecked()) } } /// 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: /// /// ``` #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shr(4), Some(0x1));")] #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shr(129), None);")] /// ``` #[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 { let (a, b) = self.overflowing_shr(rhs); if unlikely!(b) {None} else {Some(a)} } /// Unchecked shift right. Computes `self >> rhs`, assuming that /// `rhs` is less than the number of bits in `self`. /// /// # Safety /// /// This results in undefined behavior if `rhs` is larger than /// or equal to the number of bits in `self`, /// i.e. when [`checked_shr`] would return `None`. /// #[doc = concat!("[`checked_shr`]: ", stringify!($SelfT), "::checked_shr")] #[unstable( feature = "unchecked_math", reason = "niche optimization path", issue = "85122", )] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[rustc_const_unstable(feature = "const_inherent_unchecked_arith", issue = "85122")] #[inline(always)] #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces pub const unsafe fn unchecked_shr(self, rhs: u32) -> Self { // SAFETY: the caller must uphold the safety contract for // `unchecked_shr`. // Any legal shift amount is losslessly representable in the self type. unsafe { intrinsics::unchecked_shr(self, rhs.try_into().ok().unwrap_unchecked()) } } /// Checked exponentiation. Computes `self.pow(exp)`, returning `None` if /// overflow occurred. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_pow(5), Some(32));")] #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_pow(2), None);")] /// ``` #[stable(feature = "no_panic_pow", since = "1.34.0")] #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] pub const fn checked_pow(self, mut exp: u32) -> Option { if exp == 0 { return Some(1); } let mut base = self; let mut acc: Self = 1; while exp > 1 { if (exp & 1) == 1 { acc = try_opt!(acc.checked_mul(base)); } exp /= 2; base = try_opt!(base.checked_mul(base)); } // since exp!=0, finally the exp must be 1. // Deal with the final bit of the exponent separately, since // squaring the base afterwards is not necessary and may cause a // needless overflow. acc.checked_mul(base) } /// Saturating integer addition. Computes `self + rhs`, saturating at /// the numeric bounds instead of overflowing. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_add(1), 101);")] #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_add(127), ", stringify!($SelfT), "::MAX);")] /// ``` #[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(always)] pub const fn saturating_add(self, rhs: Self) -> Self { intrinsics::saturating_add(self, rhs) } /// Saturating addition with a signed integer. Computes `self + rhs`, /// saturating at the numeric bounds instead of overflowing. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_add_signed(2), 3);")] #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_add_signed(-2), 0);")] #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).saturating_add_signed(4), ", stringify!($SelfT), "::MAX);")] /// ``` #[stable(feature = "mixed_integer_ops", since = "1.66.0")] #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] pub const fn saturating_add_signed(self, rhs: $SignedT) -> Self { let (res, overflow) = self.overflowing_add(rhs as Self); if overflow == (rhs < 0) { res } else if overflow { Self::MAX } else { 0 } } /// Saturating integer subtraction. Computes `self - rhs`, saturating /// at the numeric bounds instead of overflowing. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_sub(27), 73);")] #[doc = concat!("assert_eq!(13", stringify!($SelfT), ".saturating_sub(127), 0);")] /// ``` #[stable(feature = "rust1", since = "1.0.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")] #[inline(always)] pub const fn saturating_sub(self, rhs: Self) -> Self { intrinsics::saturating_sub(self, rhs) } /// Saturating integer multiplication. Computes `self * rhs`, /// saturating at the numeric bounds instead of overflowing. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".saturating_mul(10), 20);")] #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX).saturating_mul(10), ", stringify!($SelfT),"::MAX);")] /// ``` #[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, } } /// Saturating integer division. Computes `self / rhs`, saturating at the /// numeric bounds instead of overflowing. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".saturating_div(2), 2);")] /// /// ``` /// /// ```should_panic #[doc = concat!("let _ = 1", stringify!($SelfT), ".saturating_div(0);")] /// /// ``` #[stable(feature = "saturating_div", since = "1.58.0")] #[rustc_const_stable(feature = "saturating_div", since = "1.58.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] pub const fn saturating_div(self, rhs: Self) -> Self { // on unsigned types, there is no overflow in integer division self.wrapping_div(rhs) } /// Saturating integer exponentiation. Computes `self.pow(exp)`, /// saturating at the numeric bounds instead of overflowing. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(4", stringify!($SelfT), ".saturating_pow(3), 64);")] #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_pow(2), ", stringify!($SelfT), "::MAX);")] /// ``` #[stable(feature = "no_panic_pow", since = "1.34.0")] #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] pub const fn saturating_pow(self, exp: u32) -> Self { match self.checked_pow(exp) { Some(x) => x, None => Self::MAX, } } /// Wrapping (modular) addition. Computes `self + rhs`, /// wrapping around at the boundary of the type. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(200", stringify!($SelfT), ".wrapping_add(55), 255);")] #[doc = concat!("assert_eq!(200", stringify!($SelfT), ".wrapping_add(", stringify!($SelfT), "::MAX), 199);")] /// ``` #[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(always)] pub const fn wrapping_add(self, rhs: Self) -> Self { intrinsics::wrapping_add(self, rhs) } /// Wrapping (modular) addition with a signed integer. Computes /// `self + rhs`, wrapping around at the boundary of the type. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_add_signed(2), 3);")] #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_add_signed(-2), ", stringify!($SelfT), "::MAX);")] #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).wrapping_add_signed(4), 1);")] /// ``` #[stable(feature = "mixed_integer_ops", since = "1.66.0")] #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] pub const fn wrapping_add_signed(self, rhs: $SignedT) -> Self { self.wrapping_add(rhs as Self) } /// Wrapping (modular) subtraction. Computes `self - rhs`, /// wrapping around at the boundary of the type. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_sub(100), 0);")] #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_sub(", stringify!($SelfT), "::MAX), 101);")] /// ``` #[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(always)] 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(always)] pub const fn wrapping_mul(self, rhs: Self) -> Self { intrinsics::wrapping_mul(self, rhs) } /// 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: /// /// ``` #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_div(10), 10);")] /// ``` #[stable(feature = "num_wrapping", since = "1.2.0")] #[rustc_const_stable(feature = "const_wrapping_int_methods", since = "1.52.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline(always)] pub const fn wrapping_div(self, rhs: Self) -> Self { self / rhs } /// Wrapping Euclidean division. Computes `self.div_euclid(rhs)`. /// Wrapped division on unsigned types is just normal division. /// There's no way wrapping could ever happen. /// This function exists, so that all operations /// are accounted for in the wrapping operations. /// Since, for the positive integers, all common /// definitions of division are equal, this /// is exactly equal to `self.wrapping_div(rhs)`. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_div_euclid(10), 10);")] /// ``` #[stable(feature = "euclidean_division", since = "1.38.0")] #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline(always)] pub const fn wrapping_div_euclid(self, rhs: Self) -> Self { self / rhs } /// 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: /// /// ``` #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_rem(10), 0);")] /// ``` #[stable(feature = "num_wrapping", since = "1.2.0")] #[rustc_const_stable(feature = "const_wrapping_int_methods", since = "1.52.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline(always)] pub const fn wrapping_rem(self, rhs: Self) -> Self { self % rhs } /// Wrapping Euclidean modulo. Computes `self.rem_euclid(rhs)`. /// Wrapped modulo calculation on unsigned types is /// just the regular remainder calculation. /// There's no way wrapping could ever happen. /// This function exists, so that all operations /// are accounted for in the wrapping operations. /// Since, for the positive integers, all common /// definitions of division are equal, this /// is exactly equal to `self.wrapping_rem(rhs)`. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_rem_euclid(10), 0);")] /// ``` #[stable(feature = "euclidean_division", since = "1.38.0")] #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline(always)] 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")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline(always)] pub const fn wrapping_neg(self) -> Self { (0 as $SelfT).wrapping_sub(self) } /// Panic-free bitwise shift-left; yields `self << mask(rhs)`, /// where `mask` removes any high-order bits of `rhs` that /// would cause the shift to exceed the bitwidth of the type. /// /// Note that this is *not* the same as a rotate-left; the /// RHS of a wrapping shift-left is restricted to the range /// of the type, rather than the bits shifted out of the LHS /// being returned to the other end. The primitive integer /// types all implement a [`rotate_left`](Self::rotate_left) function, /// which may be what you want instead. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_shl(7), 128);")] #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_shl(128), 1);")] /// ``` #[stable(feature = "num_wrapping", since = "1.2.0")] #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline(always)] #[rustc_allow_const_fn_unstable(const_inherent_unchecked_arith)] pub const fn wrapping_shl(self, rhs: u32) -> Self { // SAFETY: the masking by the bitsize of the type ensures that we do not shift // out of bounds unsafe { self.unchecked_shl(rhs & (Self::BITS - 1)) } } /// Panic-free bitwise shift-right; yields `self >> mask(rhs)`, /// where `mask` removes any high-order bits of `rhs` that /// would cause the shift to exceed the bitwidth of the type. /// /// Note that this is *not* the same as a rotate-right; the /// RHS of a wrapping shift-right is restricted to the range /// of the type, rather than the bits shifted out of the LHS /// being returned to the other end. The primitive integer /// types all implement a [`rotate_right`](Self::rotate_right) function, /// which may be what you want instead. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(128", stringify!($SelfT), ".wrapping_shr(7), 1);")] #[doc = concat!("assert_eq!(128", stringify!($SelfT), ".wrapping_shr(128), 128);")] /// ``` #[stable(feature = "num_wrapping", since = "1.2.0")] #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline(always)] #[rustc_allow_const_fn_unstable(const_inherent_unchecked_arith)] pub const fn wrapping_shr(self, rhs: u32) -> Self { // SAFETY: the masking by the bitsize of the type ensures that we do not shift // out of bounds unsafe { self.unchecked_shr(rhs & (Self::BITS - 1)) } } /// Wrapping (modular) exponentiation. Computes `self.pow(exp)`, /// wrapping around at the boundary of the type. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".wrapping_pow(5), 243);")] /// assert_eq!(3u8.wrapping_pow(6), 217); /// ``` #[stable(feature = "no_panic_pow", since = "1.34.0")] #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")] #[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) } /// 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 /// /// ``` #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_add(2), (7, false));")] #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.overflowing_add(1), (0, 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(always)] pub const fn overflowing_add(self, rhs: Self) -> (Self, bool) { let (a, b) = intrinsics::add_with_overflow(self as $ActualT, rhs as $ActualT); (a as Self, b) } /// Calculates `self` + `rhs` + `carry` and returns a tuple containing /// the sum and the output carry. /// /// Performs "ternary addition" of two integer operands and a carry-in /// bit, and returns an output integer and a carry-out bit. This allows /// chaining together multiple additions to create a wider addition, and /// can be useful for bignum addition. /// #[doc = concat!("This can be thought of as a ", stringify!($BITS), "-bit \"full adder\", in the electronics sense.")] /// /// If the input carry is false, this method is equivalent to /// [`overflowing_add`](Self::overflowing_add), and the output carry is /// equal to the overflow flag. Note that although carry and overflow /// flags are similar for unsigned integers, they are different for /// signed integers. /// /// # Examples /// /// ``` /// #![feature(bigint_helper_methods)] /// #[doc = concat!("// 3 MAX (a = 3 × 2^", stringify!($BITS), " + 2^", stringify!($BITS), " - 1)")] #[doc = concat!("// + 5 7 (b = 5 × 2^", stringify!($BITS), " + 7)")] /// // --------- #[doc = concat!("// 9 6 (sum = 9 × 2^", stringify!($BITS), " + 6)")] /// #[doc = concat!("let (a1, a0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (3, ", stringify!($SelfT), "::MAX);")] #[doc = concat!("let (b1, b0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (5, 7);")] /// let carry0 = false; /// /// let (sum0, carry1) = a0.carrying_add(b0, carry0); /// assert_eq!(carry1, true); /// let (sum1, carry2) = a1.carrying_add(b1, carry1); /// assert_eq!(carry2, false); /// /// assert_eq!((sum1, sum0), (9, 6)); /// ``` #[unstable(feature = "bigint_helper_methods", issue = "85532")] #[rustc_const_unstable(feature = "const_bigint_helper_methods", issue = "85532")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] pub const fn carrying_add(self, rhs: Self, carry: bool) -> (Self, bool) { // note: longer-term this should be done via an intrinsic, but this has been shown // to generate optimal code for now, and LLVM doesn't have an equivalent intrinsic let (a, b) = self.overflowing_add(rhs); let (c, d) = a.overflowing_add(carry as $SelfT); (c, b || d) } /// Calculates `self` + `rhs` with a signed `rhs` /// /// Returns a tuple of the addition along with a boolean indicating /// whether an arithmetic overflow would occur. If an overflow would /// have occurred then the wrapped value is returned. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_add_signed(2), (3, false));")] #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_add_signed(-2), (", stringify!($SelfT), "::MAX, true));")] #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).overflowing_add_signed(4), (1, true));")] /// ``` #[stable(feature = "mixed_integer_ops", since = "1.66.0")] #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] pub const fn overflowing_add_signed(self, rhs: $SignedT) -> (Self, bool) { let (res, overflowed) = self.overflowing_add(rhs as Self); (res, overflowed ^ (rhs < 0)) } /// Calculates `self` - `rhs` /// /// Returns a tuple of the subtraction along with a boolean indicating /// whether an arithmetic overflow would occur. If an overflow would /// have occurred then the wrapped value is returned. /// /// # Examples /// /// Basic usage /// /// ``` #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_sub(2), (3, false));")] #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".overflowing_sub(1), (", stringify!($SelfT), "::MAX, 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(always)] pub const fn overflowing_sub(self, rhs: Self) -> (Self, bool) { let (a, b) = intrinsics::sub_with_overflow(self as $ActualT, rhs as $ActualT); (a as Self, b) } /// Calculates `self` − `rhs` − `borrow` and returns a tuple /// containing the difference and the output borrow. /// /// Performs "ternary subtraction" by subtracting both an integer /// operand and a borrow-in bit from `self`, and returns an output /// integer and a borrow-out bit. This allows chaining together multiple /// subtractions to create a wider subtraction, and can be useful for /// bignum subtraction. /// /// # Examples /// /// ``` /// #![feature(bigint_helper_methods)] /// #[doc = concat!("// 9 6 (a = 9 × 2^", stringify!($BITS), " + 6)")] #[doc = concat!("// - 5 7 (b = 5 × 2^", stringify!($BITS), " + 7)")] /// // --------- #[doc = concat!("// 3 MAX (diff = 3 × 2^", stringify!($BITS), " + 2^", stringify!($BITS), " - 1)")] /// #[doc = concat!("let (a1, a0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (9, 6);")] #[doc = concat!("let (b1, b0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (5, 7);")] /// let borrow0 = false; /// /// let (diff0, borrow1) = a0.borrowing_sub(b0, borrow0); /// assert_eq!(borrow1, true); /// let (diff1, borrow2) = a1.borrowing_sub(b1, borrow1); /// assert_eq!(borrow2, false); /// #[doc = concat!("assert_eq!((diff1, diff0), (3, ", stringify!($SelfT), "::MAX));")] /// ``` #[unstable(feature = "bigint_helper_methods", issue = "85532")] #[rustc_const_unstable(feature = "const_bigint_helper_methods", issue = "85532")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] pub const fn borrowing_sub(self, rhs: Self, borrow: bool) -> (Self, bool) { // note: longer-term this should be done via an intrinsic, but this has been shown // to generate optimal code for now, and LLVM doesn't have an equivalent intrinsic let (a, b) = self.overflowing_sub(rhs); let (c, d) = a.overflowing_sub(borrow as $SelfT); (c, b || d) } /// Computes the absolute difference between `self` and `other`. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".abs_diff(80), 20", stringify!($SelfT), ");")] #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".abs_diff(110), 10", stringify!($SelfT), ");")] /// ``` #[stable(feature = "int_abs_diff", since = "1.60.0")] #[rustc_const_stable(feature = "int_abs_diff", since = "1.60.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] pub const fn abs_diff(self, other: Self) -> Self { if mem::size_of::() == 1 { // Trick LLVM into generating the psadbw instruction when SSE2 // is available and this function is autovectorized for u8's. (self as i32).wrapping_sub(other as i32).abs() as Self } else { if self < other { other - self } else { self - other } } } /// 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(always)] pub const fn overflowing_mul(self, rhs: Self) -> (Self, bool) { let (a, b) = intrinsics::mul_with_overflow(self as $ActualT, rhs as $ActualT); (a as Self, b) } /// Calculates the divisor when `self` is divided by `rhs`. /// /// Returns a tuple of the divisor along with a boolean indicating /// whether an arithmetic overflow would occur. Note that for unsigned /// integers overflow never occurs, so the second value is always /// `false`. /// /// # Panics /// /// This function will panic if `rhs` is 0. /// /// # Examples /// /// Basic usage /// /// ``` #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_div(2), (2, false));")] /// ``` #[inline(always)] #[stable(feature = "wrapping", since = "1.7.0")] #[rustc_const_stable(feature = "const_overflowing_int_methods", since = "1.52.0")] #[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) } /// 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 /// /// ``` #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_div_euclid(2), (2, false));")] /// ``` #[inline(always)] #[stable(feature = "euclidean_division", since = "1.38.0")] #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] pub const fn overflowing_div_euclid(self, rhs: Self) -> (Self, bool) { (self / rhs, false) } /// Calculates the remainder when `self` is divided by `rhs`. /// /// Returns a tuple of the remainder after dividing along with a boolean /// indicating whether an arithmetic overflow would occur. Note that for /// unsigned integers overflow never occurs, so the second value is /// always `false`. /// /// # Panics /// /// This function will panic if `rhs` is 0. /// /// # Examples /// /// Basic usage /// /// ``` #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_rem(2), (1, false));")] /// ``` #[inline(always)] #[stable(feature = "wrapping", since = "1.7.0")] #[rustc_const_stable(feature = "const_overflowing_int_methods", since = "1.52.0")] #[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) } /// 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 /// /// ``` #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_rem_euclid(2), (1, false));")] /// ``` #[inline(always)] #[stable(feature = "euclidean_division", since = "1.38.0")] #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] pub const fn overflowing_rem_euclid(self, rhs: Self) -> (Self, bool) { (self % rhs, false) } /// Negates self in an overflowing fashion. /// /// Returns `!self + 1` using wrapping operations to return the value /// that represents the negation of this unsigned value. Note that for /// positive unsigned values overflow always occurs, but negating 0 does /// not overflow. /// /// # Examples /// /// Basic usage /// /// ``` #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".overflowing_neg(), (0, false));")] #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".overflowing_neg(), (-2i32 as ", stringify!($SelfT), ", true));")] /// ``` #[inline(always)] #[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"] pub const fn overflowing_neg(self) -> (Self, bool) { ((!self).wrapping_add(1), self != 0) } /// 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 /// /// ``` #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".overflowing_shl(4), (0x10, false));")] #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".overflowing_shl(132), (0x10, 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(always)] pub const fn overflowing_shl(self, rhs: u32) -> (Self, bool) { (self.wrapping_shl(rhs), rhs >= Self::BITS) } /// 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 /// /// ``` #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shr(4), (0x1, false));")] #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shr(132), (0x1, 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(always)] pub const fn overflowing_shr(self, rhs: u32) -> (Self, bool) { (self.wrapping_shr(rhs), rhs >= Self::BITS) } /// 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: /// /// ``` #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".overflowing_pow(5), (243, false));")] /// assert_eq!(3u8.overflowing_pow(6), (217, true)); /// ``` #[stable(feature = "no_panic_pow", since = "1.34.0")] #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] pub const fn overflowing_pow(self, mut exp: u32) -> (Self, bool) { if exp == 0{ return (1,false); } let mut base = self; let mut acc: Self = 1; let mut overflown = false; // Scratch space for storing results of overflowing_mul. let mut r; while exp > 1 { if (exp & 1) == 1 { r = acc.overflowing_mul(base); acc = r.0; overflown |= r.1; } exp /= 2; r = base.overflowing_mul(base); base = r.0; overflown |= r.1; } // since exp!=0, finally the exp must be 1. // Deal with the final bit of the exponent separately, since // squaring the base afterwards is not necessary and may cause a // needless overflow. r = acc.overflowing_mul(base); r.1 |= overflown; r } /// Raises self to the power of `exp`, using exponentiation by squaring. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".pow(5), 32);")] /// ``` #[stable(feature = "rust1", since = "1.0.0")] #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")] #[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 } /// 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: /// /// ``` #[doc = concat!("assert_eq!(7", stringify!($SelfT), ".div_euclid(4), 1); // or any other integer type")] /// ``` #[stable(feature = "euclidean_division", since = "1.38.0")] #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline(always)] #[rustc_inherit_overflow_checks] pub const fn div_euclid(self, rhs: Self) -> Self { self / rhs } /// Calculates the least remainder of `self (mod rhs)`. /// /// Since, for the positive integers, all common /// definitions of division are equal, this /// is exactly equal to `self % rhs`. /// /// # Panics /// /// This function will panic if `rhs` is 0. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(7", stringify!($SelfT), ".rem_euclid(4), 3); // or any other integer type")] /// ``` #[stable(feature = "euclidean_division", since = "1.38.0")] #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline(always)] #[rustc_inherit_overflow_checks] pub const fn rem_euclid(self, rhs: Self) -> Self { self % rhs } /// Calculates the quotient of `self` and `rhs`, rounding the result towards negative infinity. /// /// This is the same as performing `self / rhs` for all unsigned integers. /// /// # Panics /// /// This function will panic if `rhs` is zero. /// /// # Examples /// /// Basic usage: /// /// ``` /// #![feature(int_roundings)] #[doc = concat!("assert_eq!(7_", stringify!($SelfT), ".div_floor(4), 1);")] /// ``` #[unstable(feature = "int_roundings", issue = "88581")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline(always)] pub const fn div_floor(self, rhs: Self) -> Self { self / rhs } /// Calculates the quotient of `self` and `rhs`, rounding the result towards positive infinity. /// /// # Panics /// /// This function will panic if `rhs` is zero. /// /// ## Overflow behavior /// /// On overflow, this function will panic if overflow checks are enabled (default in debug /// mode) and wrap if overflow checks are disabled (default in release mode). /// /// # Examples /// /// Basic usage: /// /// ``` /// #![feature(int_roundings)] #[doc = concat!("assert_eq!(7_", stringify!($SelfT), ".div_ceil(4), 2);")] /// ``` #[unstable(feature = "int_roundings", issue = "88581")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] #[rustc_inherit_overflow_checks] pub const fn div_ceil(self, rhs: Self) -> Self { let d = self / rhs; let r = self % rhs; if r > 0 && rhs > 0 { d + 1 } else { d } } /// Calculates the smallest value greater than or equal to `self` that /// is a multiple of `rhs`. /// /// # Panics /// /// This function will panic if `rhs` is zero. /// /// ## Overflow behavior /// /// On overflow, this function will panic if overflow checks are enabled (default in debug /// mode) and wrap if overflow checks are disabled (default in release mode). /// /// # Examples /// /// Basic usage: /// /// ``` /// #![feature(int_roundings)] #[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".next_multiple_of(8), 16);")] #[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".next_multiple_of(8), 24);")] /// ``` #[unstable(feature = "int_roundings", issue = "88581")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] #[rustc_inherit_overflow_checks] pub const fn next_multiple_of(self, rhs: Self) -> Self { match self % rhs { 0 => self, r => self + (rhs - r) } } /// Calculates the smallest value greater than or equal to `self` that /// is a multiple of `rhs`. Returns `None` if `rhs` is zero or the /// operation would result in overflow. /// /// # Examples /// /// Basic usage: /// /// ``` /// #![feature(int_roundings)] #[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".checked_next_multiple_of(8), Some(16));")] #[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".checked_next_multiple_of(8), Some(24));")] #[doc = concat!("assert_eq!(1_", stringify!($SelfT), ".checked_next_multiple_of(0), None);")] #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_next_multiple_of(2), None);")] /// ``` #[unstable(feature = "int_roundings", issue = "88581")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] pub const fn checked_next_multiple_of(self, rhs: Self) -> Option { match try_opt!(self.checked_rem(rhs)) { 0 => Some(self), // rhs - r cannot overflow because r is smaller than rhs r => self.checked_add(rhs - r) } } /// Returns `true` if and only if `self == 2^k` for some `k`. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert!(16", stringify!($SelfT), ".is_power_of_two());")] #[doc = concat!("assert!(!10", stringify!($SelfT), ".is_power_of_two());")] /// ``` #[must_use] #[stable(feature = "rust1", since = "1.0.0")] #[rustc_const_stable(feature = "const_is_power_of_two", since = "1.32.0")] #[inline(always)] 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_stable(feature = "const_int_pow", since = "1.50.0")] 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) }; <$SelfT>::MAX >> z } /// Returns the smallest power of two greater than or equal to `self`. /// /// When return value overflows (i.e., `self > (1 << (N-1))` for type /// `uN`), it panics in debug mode and the return value is wrapped to 0 in /// release mode (the only situation in which method can return 0). /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".next_power_of_two(), 2);")] #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".next_power_of_two(), 4);")] /// ``` #[stable(feature = "rust1", since = "1.0.0")] #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] #[rustc_inherit_overflow_checks] pub const fn next_power_of_two(self) -> Self { self.one_less_than_next_power_of_two() + 1 } /// Returns the smallest power of two greater than or equal to `n`. If /// the next power of two is greater than the type's maximum value, /// `None` is returned, otherwise the power of two is wrapped in `Some`. /// /// # Examples /// /// Basic usage: /// /// ``` #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_next_power_of_two(), Some(2));")] #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".checked_next_power_of_two(), Some(4));")] #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_next_power_of_two(), None);")] /// ``` #[inline] #[stable(feature = "rust1", since = "1.0.0")] #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] pub const fn checked_next_power_of_two(self) -> Option { self.one_less_than_next_power_of_two().checked_add(1) } /// 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)] /// #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".wrapping_next_power_of_two(), 2);")] #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".wrapping_next_power_of_two(), 4);")] #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_next_power_of_two(), 0);")] /// ``` #[inline] #[unstable(feature = "wrapping_next_power_of_two", issue = "32463", reason = "needs decision on wrapping behaviour")] #[rustc_const_unstable(feature = "wrapping_next_power_of_two", issue = "32463")] #[must_use = "this returns the result of the operation, \ without modifying the original"] pub const fn wrapping_next_power_of_two(self) -> Self { self.one_less_than_next_power_of_two().wrapping_add(1) } /// Return the memory representation of this integer as a byte array in /// big-endian (network) byte order. /// #[doc = $to_xe_bytes_doc] /// /// # Examples /// /// ``` #[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_be_bytes();")] #[doc = concat!("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")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] pub const fn to_be_bytes(self) -> [u8; mem::size_of::()] { self.to_be().to_ne_bytes() } /// Return the memory representation of this integer as a byte array in /// little-endian byte order. /// #[doc = $to_xe_bytes_doc] /// /// # Examples /// /// ``` #[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_le_bytes();")] #[doc = concat!("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")] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] pub const fn to_le_bytes(self) -> [u8; mem::size_of::()] { self.to_le().to_ne_bytes() } /// 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. /// #[doc = $to_xe_bytes_doc] /// /// [`to_be_bytes`]: Self::to_be_bytes /// [`to_le_bytes`]: Self::to_le_bytes /// /// # Examples /// /// ``` #[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_ne_bytes();")] /// assert_eq!( /// bytes, /// if cfg!(target_endian = "big") { #[doc = concat!(" ", $be_bytes)] /// } else { #[doc = concat!(" ", $le_bytes)] /// } /// ); /// ``` #[stable(feature = "int_to_from_bytes", since = "1.32.0")] #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")] #[must_use = "this returns the result of the operation, \ without modifying the original"] // SAFETY: const sound because integers are plain old datatypes so we can always // transmute them to arrays of bytes #[inline] pub const fn to_ne_bytes(self) -> [u8; mem::size_of::()] { // SAFETY: integers are plain old datatypes so we can always transmute them to // arrays of bytes unsafe { mem::transmute(self) } } /// Create a native endian integer value from its representation /// as a byte array in big endian. /// #[doc = $from_xe_bytes_doc] /// /// # Examples /// /// ``` #[doc = concat!("let value = ", stringify!($SelfT), "::from_be_bytes(", $be_bytes, ");")] #[doc = concat!("assert_eq!(value, ", $swap_op, ");")] /// ``` /// /// When starting from a slice rather than an array, fallible conversion APIs can be used: /// /// ``` #[doc = concat!("fn read_be_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")] #[doc = concat!(" let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">());")] /// *input = rest; #[doc = concat!(" ", 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")] #[must_use] #[inline] pub const fn from_be_bytes(bytes: [u8; mem::size_of::()]) -> Self { Self::from_be(Self::from_ne_bytes(bytes)) } /// Create a native endian integer value from its representation /// as a byte array in little endian. /// #[doc = $from_xe_bytes_doc] /// /// # Examples /// /// ``` #[doc = concat!("let value = ", stringify!($SelfT), "::from_le_bytes(", $le_bytes, ");")] #[doc = concat!("assert_eq!(value, ", $swap_op, ");")] /// ``` /// /// When starting from a slice rather than an array, fallible conversion APIs can be used: /// /// ``` #[doc = concat!("fn read_le_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")] #[doc = concat!(" let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">());")] /// *input = rest; #[doc = concat!(" ", 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")] #[must_use] #[inline] pub const fn from_le_bytes(bytes: [u8; mem::size_of::()]) -> Self { Self::from_le(Self::from_ne_bytes(bytes)) } /// Create a native endian 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`]: Self::from_be_bytes /// [`from_le_bytes`]: Self::from_le_bytes /// #[doc = $from_xe_bytes_doc] /// /// # Examples /// /// ``` #[doc = concat!("let value = ", stringify!($SelfT), "::from_ne_bytes(if cfg!(target_endian = \"big\") {")] #[doc = concat!(" ", $be_bytes, "")] /// } else { #[doc = concat!(" ", $le_bytes, "")] /// }); #[doc = concat!("assert_eq!(value, ", $swap_op, ");")] /// ``` /// /// When starting from a slice rather than an array, fallible conversion APIs can be used: /// /// ``` #[doc = concat!("fn read_ne_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")] #[doc = concat!(" let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">());")] /// *input = rest; #[doc = concat!(" ", stringify!($SelfT), "::from_ne_bytes(int_bytes.try_into().unwrap())")] /// } /// ``` #[stable(feature = "int_to_from_bytes", since = "1.32.0")] #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")] #[must_use] // SAFETY: const sound because integers are plain old datatypes so we can always // transmute to them #[inline] pub const fn from_ne_bytes(bytes: [u8; mem::size_of::()]) -> Self { // SAFETY: integers are plain old datatypes so we can always transmute to them unsafe { mem::transmute(bytes) } } /// New code should prefer to use #[doc = concat!("[`", stringify!($SelfT), "::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")] #[deprecated(since = "TBD", note = "replaced by the `MIN` associated constant on this type")] pub const fn min_value() -> Self { Self::MIN } /// New code should prefer to use #[doc = concat!("[`", stringify!($SelfT), "::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")] #[deprecated(since = "TBD", note = "replaced by the `MAX` associated constant on this type")] pub const fn max_value() -> Self { Self::MAX } } }