(a as Self, b)
}
+ /// Calculates `self + rhs + carry` without the ability to overflow.
+ ///
+ /// Performs "ternary addition" which takes in an extra bit to add, and may return an
+ /// additional bit of overflow. This allows for chaining together multiple additions
+ /// to create "big integers" which represent larger values.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage
+ ///
+ /// ```
+ /// #![feature(bigint_helper_methods)]
+ #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".carrying_add(2, false), (7, false));")]
+ #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".carrying_add(2, true), (8, false));")]
+ #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.carrying_add(1, false), (", stringify!($SelfT), "::MIN, false));")]
+ #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.carrying_add(1, true), (", stringify!($SelfT), "::MIN + 1, false));")]
+ /// ```
+ #[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) {
+ let (sum, carry) = (self as $UnsignedT).carrying_add(rhs as $UnsignedT, carry);
+ (sum as $SelfT, carry)
+ }
+
/// Calculates `self` - `rhs`
///
/// Returns a tuple of the subtraction along with a boolean indicating whether an arithmetic overflow
(a as Self, b)
}
+ /// Calculates `self - rhs - borrow` without the ability to overflow.
+ ///
+ /// Performs "ternary subtraction" which takes in an extra bit to subtract, and may return
+ /// an additional bit of overflow. This allows for chaining together multiple subtractions
+ /// to create "big integers" which represent larger values.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage
+ ///
+ /// ```
+ /// #![feature(bigint_helper_methods)]
+ #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".borrowing_sub(2, false), (3, false));")]
+ #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".borrowing_sub(2, true), (2, false));")]
+ #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.borrowing_sub(1, false), (", stringify!($SelfT), "::MAX, false));")]
+ #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.borrowing_sub(1, true), (", stringify!($SelfT), "::MAX - 1, false));")]
+ /// ```
+ #[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) {
+ let (sum, borrow) = (self as $UnsignedT).borrowing_sub(rhs as $UnsignedT, borrow);
+ (sum as $SelfT, borrow)
+ }
+
/// Calculates the multiplication of `self` and `rhs`.
///
/// Returns a tuple of the multiplication along with a boolean indicating whether an arithmetic overflow
};
}
+macro_rules! widening_impl {
+ ($SelfT:ty, $WideT:ty, $BITS:literal) => {
+ /// Calculates the complete product `self * rhs` without the possibility to overflow.
+ ///
+ /// This returns the low-order (wrapping) bits and the high-order (overflow) bits
+ /// of the result as two separate values, in that order.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// Please note that this example is shared between integer types.
+ /// Which explains why `u32` is used here.
+ ///
+ /// ```
+ /// #![feature(bigint_helper_methods)]
+ /// assert_eq!(5u32.widening_mul(2), (10, 0));
+ /// assert_eq!(1_000_000_000u32.widening_mul(10), (1410065408, 2));
+ /// ```
+ #[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 widening_mul(self, rhs: Self) -> (Self, Self) {
+ // note: longer-term this should be done via an intrinsic,
+ // but for now we can deal without an impl for u128/i128
+ // SAFETY: overflow will be contained within the wider types
+ let wide = unsafe { (self as $WideT).unchecked_mul(rhs as $WideT) };
+ (wide as $SelfT, (wide >> $BITS) as $SelfT)
+ }
+
+ /// Calculates the "full multiplication" `self * rhs + carry`
+ /// without the possibility to overflow.
+ ///
+ /// This returns the low-order (wrapping) bits and the high-order (overflow) bits
+ /// of the result as two separate values, in that order.
+ ///
+ /// Performs "long multiplication" which takes in an extra amount to add, and may return an
+ /// additional amount of overflow. This allows for chaining together multiple
+ /// multiplications to create "big integers" which represent larger values.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage:
+ ///
+ /// Please note that this example is shared between integer types.
+ /// Which explains why `u32` is used here.
+ ///
+ /// ```
+ /// #![feature(bigint_helper_methods)]
+ /// assert_eq!(5u32.carrying_mul(2, 0), (10, 0));
+ /// assert_eq!(5u32.carrying_mul(2, 10), (20, 0));
+ /// assert_eq!(1_000_000_000u32.carrying_mul(10, 0), (1410065408, 2));
+ /// assert_eq!(1_000_000_000u32.carrying_mul(10, 10), (1410065418, 2));
+ /// ```
+ #[unstable(feature = "bigint_helper_methods", issue = "85532")]
+ #[rustc_const_unstable(feature = "bigint_helper_methods", issue = "85532")]
+ #[must_use = "this returns the result of the operation, \
+ without modifying the original"]
+ #[inline]
+ pub const fn carrying_mul(self, rhs: Self, carry: Self) -> (Self, Self) {
+ // note: longer-term this should be done via an intrinsic,
+ // but for now we can deal without an impl for u128/i128
+ // SAFETY: overflow will be contained within the wider types
+ let wide = unsafe {
+ (self as $WideT).unchecked_mul(rhs as $WideT).unchecked_add(carry as $WideT)
+ };
+ (wide as $SelfT, (wide >> $BITS) as $SelfT)
+ }
+ };
+}
+
#[lang = "i8"]
impl i8 {
+ widening_impl! { i8, i16, 8 }
int_impl! { i8, i8, u8, 8, 7, -128, 127, 2, "-0x7e", "0xa", "0x12", "0x12", "0x48",
"[0x12]", "[0x12]", "", "" }
}
#[lang = "i16"]
impl i16 {
+ widening_impl! { i16, i32, 16 }
int_impl! { i16, i16, u16, 16, 15, -32768, 32767, 4, "-0x5ffd", "0x3a", "0x1234", "0x3412",
"0x2c48", "[0x34, 0x12]", "[0x12, 0x34]", "", "" }
}
#[lang = "i32"]
impl i32 {
+ widening_impl! { i32, i64, 32 }
int_impl! { i32, i32, u32, 32, 31, -2147483648, 2147483647, 8, "0x10000b3", "0xb301",
"0x12345678", "0x78563412", "0x1e6a2c48", "[0x78, 0x56, 0x34, 0x12]",
"[0x12, 0x34, 0x56, 0x78]", "", "" }
#[lang = "i64"]
impl i64 {
+ widening_impl! { i64, i128, 64 }
int_impl! { i64, i64, u64, 64, 63, -9223372036854775808, 9223372036854775807, 12,
"0xaa00000000006e1", "0x6e10aa", "0x1234567890123456", "0x5634129078563412",
"0x6a2c48091e6a2c48", "[0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]",
#[cfg(target_pointer_width = "16")]
#[lang = "isize"]
impl isize {
+ widening_impl! { isize, i32, 16 }
int_impl! { isize, i16, usize, 16, 15, -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 {
+ widening_impl! { isize, i64, 32 }
int_impl! { isize, i32, usize, 32, 31, -2147483648, 2147483647, 8, "0x10000b3", "0xb301",
"0x12345678", "0x78563412", "0x1e6a2c48", "[0x78, 0x56, 0x34, 0x12]",
"[0x12, 0x34, 0x56, 0x78]",
#[cfg(target_pointer_width = "64")]
#[lang = "isize"]
impl isize {
+ widening_impl! { isize, i128, 64 }
int_impl! { isize, i64, usize, 64, 63, -9223372036854775808, 9223372036854775807,
12, "0xaa00000000006e1", "0x6e10aa", "0x1234567890123456", "0x5634129078563412",
"0x6a2c48091e6a2c48", "[0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]",
#[lang = "u8"]
impl u8 {
+ widening_impl! { u8, u16, 8 }
uint_impl! { u8, u8, 8, 255, 2, "0x82", "0xa", "0x12", "0x12", "0x48", "[0x12]",
"[0x12]", "", "" }
#[lang = "u16"]
impl u16 {
+ widening_impl! { u16, u32, 16 }
uint_impl! { u16, u16, 16, 65535, 4, "0xa003", "0x3a", "0x1234", "0x3412", "0x2c48",
"[0x34, 0x12]", "[0x12, 0x34]", "", "" }
}
#[lang = "u32"]
impl u32 {
+ widening_impl! { u32, u64, 32 }
uint_impl! { u32, u32, 32, 4294967295, 8, "0x10000b3", "0xb301", "0x12345678",
"0x78563412", "0x1e6a2c48", "[0x78, 0x56, 0x34, 0x12]", "[0x12, 0x34, 0x56, 0x78]", "", "" }
}
#[lang = "u64"]
impl u64 {
+ widening_impl! { u64, u128, 64 }
uint_impl! { u64, u64, 64, 18446744073709551615, 12, "0xaa00000000006e1", "0x6e10aa",
"0x1234567890123456", "0x5634129078563412", "0x6a2c48091e6a2c48",
"[0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]",
#[cfg(target_pointer_width = "16")]
#[lang = "usize"]
impl usize {
+ widening_impl! { usize, u32, 16 }
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 {
+ widening_impl! { usize, u64, 32 }
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 {
+ widening_impl! { usize, u128, 64 }
uint_impl! { usize, u64, 64, 18446744073709551615, 12, "0xaa00000000006e1", "0x6e10aa",
"0x1234567890123456", "0x5634129078563412", "0x6a2c48091e6a2c48",
"[0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]",
(a as Self, b)
}
+ /// Calculates `self + rhs + carry` without the ability to overflow.
+ ///
+ /// Performs "ternary addition" which takes in an extra bit to add, and may return an
+ /// additional bit of overflow. This allows for chaining together multiple additions
+ /// to create "big integers" which represent larger values.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage
+ ///
+ /// ```
+ /// #![feature(bigint_helper_methods)]
+ #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".carrying_add(2, false), (7, false));")]
+ #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".carrying_add(2, true), (8, false));")]
+ #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.carrying_add(1, false), (0, true));")]
+ #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.carrying_add(1, true), (1, true));")]
+ /// ```
+ #[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 $SelfT);
+ (c, b | d)
+ }
+
/// Calculates `self` - `rhs`
///
/// Returns a tuple of the subtraction along with a boolean indicating
(a as Self, b)
}
+ /// Calculates `self - rhs - borrow` without the ability to overflow.
+ ///
+ /// Performs "ternary subtraction" which takes in an extra bit to subtract, and may return
+ /// an additional bit of overflow. This allows for chaining together multiple subtractions
+ /// to create "big integers" which represent larger values.
+ ///
+ /// # Examples
+ ///
+ /// Basic usage
+ ///
+ /// ```
+ /// #![feature(bigint_helper_methods)]
+ #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".borrowing_sub(2, false), (3, false));")]
+ #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".borrowing_sub(2, true), (2, false));")]
+ #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".borrowing_sub(1, false), (", stringify!($SelfT), "::MAX, true));")]
+ #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".borrowing_sub(1, true), (", stringify!($SelfT), "::MAX - 1, true));")]
+ /// ```
+ #[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)
+ }
+
/// Calculates the multiplication of `self` and `rhs`.
///
/// Returns a tuple of the multiplication along with a boolean
projects / rust.git / commitdiff