diff options
Diffstat (limited to 'library/core/src/num/int_macros.rs')
| -rw-r--r-- | library/core/src/num/int_macros.rs | 80 |
1 files changed, 55 insertions, 25 deletions
diff --git a/library/core/src/num/int_macros.rs b/library/core/src/num/int_macros.rs index 2cae98b8e..aec15212d 100644 --- a/library/core/src/num/int_macros.rs +++ b/library/core/src/num/int_macros.rs @@ -1,11 +1,31 @@ macro_rules! int_impl { - ($SelfT:ty, $ActualT:ident, $UnsignedT:ty, $BITS:expr, $BITS_MINUS_ONE:expr, $Min:expr, $Max: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, - $bound_condition:expr) => { + ( + Self = $SelfT:ty, + ActualT = $ActualT:ident, + UnsignedT = $UnsignedT:ty, + + // 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, + BITS_MINUS_ONE = $BITS_MINUS_ONE:literal, + Min = $Min:literal, + Max = $Max: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 - #[doc = concat!("(−2<sup>", $BITS_MINUS_ONE, "</sup>", $bound_condition, ")")] + #[doc = concat!("(−2<sup>", $BITS_MINUS_ONE, "</sup>", $bound_condition, ").")] /// /// # Examples /// @@ -15,10 +35,10 @@ macro_rules! int_impl { #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN, ", stringify!($Min), ");")] /// ``` #[stable(feature = "assoc_int_consts", since = "1.43.0")] - pub const MIN: Self = !0 ^ ((!0 as $UnsignedT) >> 1) as Self; + pub const MIN: Self = !Self::MAX; /// The largest value that can be represented by this integer type - #[doc = concat!("(2<sup>", $BITS_MINUS_ONE, "</sup> − 1", $bound_condition, ")")] + #[doc = concat!("(2<sup>", $BITS_MINUS_ONE, "</sup> − 1", $bound_condition, ").")] /// /// # Examples /// @@ -28,7 +48,7 @@ macro_rules! int_impl { #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX, ", stringify!($Max), ");")] /// ``` #[stable(feature = "assoc_int_consts", since = "1.43.0")] - pub const MAX: Self = !Self::MIN; + pub const MAX: Self = (<$UnsignedT>::MAX >> 1) as Self; /// The size of this integer type in bits. /// @@ -38,7 +58,7 @@ macro_rules! int_impl { #[doc = concat!("assert_eq!(", stringify!($SelfT), "::BITS, ", stringify!($BITS), ");")] /// ``` #[stable(feature = "int_bits_const", since = "1.53.0")] - pub const BITS: u32 = $BITS; + pub const BITS: u32 = <$UnsignedT>::BITS; /// Converts a string slice in a given base to an integer. /// @@ -1365,7 +1385,7 @@ macro_rules! int_impl { // SAFETY: the masking by the bitsize of the type ensures that we do not shift // out of bounds unsafe { - self.unchecked_shl(rhs & ($BITS - 1)) + self.unchecked_shl(rhs & (Self::BITS - 1)) } } @@ -1395,7 +1415,7 @@ macro_rules! int_impl { // SAFETY: the masking by the bitsize of the type ensures that we do not shift // out of bounds unsafe { - self.unchecked_shr(rhs & ($BITS - 1)) + self.unchecked_shr(rhs & (Self::BITS - 1)) } } @@ -1901,7 +1921,7 @@ macro_rules! int_impl { without modifying the original"] #[inline] pub const fn overflowing_shl(self, rhs: u32) -> (Self, bool) { - (self.wrapping_shl(rhs), (rhs > ($BITS - 1))) + (self.wrapping_shl(rhs), rhs >= Self::BITS) } /// Shifts self right by `rhs` bits. @@ -1924,7 +1944,7 @@ macro_rules! int_impl { without modifying the original"] #[inline] pub const fn overflowing_shr(self, rhs: u32) -> (Self, bool) { - (self.wrapping_shr(rhs), (rhs > ($BITS - 1))) + (self.wrapping_shr(rhs), rhs >= Self::BITS) } /// Computes the absolute value of `self`. @@ -2331,14 +2351,17 @@ macro_rules! int_impl { /// ``` #[stable(feature = "int_log", since = "1.67.0")] #[rustc_const_stable(feature = "int_log", since = "1.67.0")] - #[rustc_allow_const_fn_unstable(const_option)] #[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"); - self.checked_ilog(base).expect("argument of integer logarithm must be positive") + 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. @@ -2354,13 +2377,16 @@ macro_rules! int_impl { /// ``` #[stable(feature = "int_log", since = "1.67.0")] #[rustc_const_stable(feature = "int_log", since = "1.67.0")] - #[rustc_allow_const_fn_unstable(const_option)] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] #[track_caller] pub const fn ilog2(self) -> u32 { - self.checked_ilog2().expect("argument of integer logarithm must be positive") + 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. @@ -2376,13 +2402,16 @@ macro_rules! int_impl { /// ``` #[stable(feature = "int_log", since = "1.67.0")] #[rustc_const_stable(feature = "int_log", since = "1.67.0")] - #[rustc_allow_const_fn_unstable(const_option)] #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline] #[track_caller] pub const fn ilog10(self) -> u32 { - self.checked_ilog10().expect("argument of integer logarithm must be positive") + 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, @@ -2574,12 +2603,13 @@ macro_rules! int_impl { #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline(always)] + #[rustc_allow_const_fn_unstable(const_cmp)] pub const fn signum(self) -> Self { - match self { - n if n > 0 => 1, - 0 => 0, - _ => -1, - } + // Picking the right way to phrase this is complicated + // (<https://graphics.stanford.edu/~seander/bithacks.html#CopyIntegerSign>) + // so delegate it to `Ord` which is already producing -1/0/+1 + // exactly like we need and can be the place to deal with the complexity. + self.cmp(&0) as _ } /// Returns `true` if `self` is positive and `false` if the number is zero or |