Merge #193

193: Split into more modules r=cuviper a=cuviper

There should be no functional change in this.

Co-authored-by: Josh Stone <cuviper@gmail.com>

src/bigint/addition.rs

@@ -0,0 +1,239 @@
+use super::CheckedUnsignedAbs::{Negative, Positive};
+use super::Sign::{Minus, NoSign, Plus};
+use super::{BigInt, UnsignedAbs};
+
+use crate::{IsizePromotion, UsizePromotion};
+
+use core::cmp::Ordering::{Equal, Greater, Less};
+use core::iter::Sum;
+use core::mem;
+use core::ops::{Add, AddAssign};
+use num_traits::{CheckedAdd, Zero};
+
+// We want to forward to BigUint::add, but it's not clear how that will go until
+// we compare both sign and magnitude.  So we duplicate this body for every
+// val/ref combination, deferring that decision to BigUint's own forwarding.
+macro_rules! bigint_add {
+    ($a:expr, $a_owned:expr, $a_data:expr, $b:expr, $b_owned:expr, $b_data:expr) => {
+        match ($a.sign, $b.sign) {
+            (_, NoSign) => $a_owned,
+            (NoSign, _) => $b_owned,
+            // same sign => keep the sign with the sum of magnitudes
+            (Plus, Plus) | (Minus, Minus) => BigInt::from_biguint($a.sign, $a_data + $b_data),
+            // opposite signs => keep the sign of the larger with the difference of magnitudes
+            (Plus, Minus) | (Minus, Plus) => match $a.data.cmp(&$b.data) {
+                Less => BigInt::from_biguint($b.sign, $b_data - $a_data),
+                Greater => BigInt::from_biguint($a.sign, $a_data - $b_data),
+                Equal => Zero::zero(),
+            },
+        }
+    };
+}
+
+impl<'a, 'b> Add<&'b BigInt> for &'a BigInt {
+    type Output = BigInt;
+
+    #[inline]
+    fn add(self, other: &BigInt) -> BigInt {
+        bigint_add!(
+            self,
+            self.clone(),
+            &self.data,
+            other,
+            other.clone(),
+            &other.data
+        )
+    }
+}
+
+impl<'a> Add<BigInt> for &'a BigInt {
+    type Output = BigInt;
+
+    #[inline]
+    fn add(self, other: BigInt) -> BigInt {
+        bigint_add!(self, self.clone(), &self.data, other, other, other.data)
+    }
+}
+
+impl<'a> Add<&'a BigInt> for BigInt {
+    type Output = BigInt;
+
+    #[inline]
+    fn add(self, other: &BigInt) -> BigInt {
+        bigint_add!(self, self, self.data, other, other.clone(), &other.data)
+    }
+}
+
+impl Add<BigInt> for BigInt {
+    type Output = BigInt;
+
+    #[inline]
+    fn add(self, other: BigInt) -> BigInt {
+        bigint_add!(self, self, self.data, other, other, other.data)
+    }
+}
+
+impl<'a> AddAssign<&'a BigInt> for BigInt {
+    #[inline]
+    fn add_assign(&mut self, other: &BigInt) {
+        let n = mem::replace(self, BigInt::zero());
+        *self = n + other;
+    }
+}
+forward_val_assign!(impl AddAssign for BigInt, add_assign);
+
+promote_all_scalars!(impl Add for BigInt, add);
+promote_all_scalars_assign!(impl AddAssign for BigInt, add_assign);
+forward_all_scalar_binop_to_val_val_commutative!(impl Add<u32> for BigInt, add);
+forward_all_scalar_binop_to_val_val_commutative!(impl Add<u64> for BigInt, add);
+forward_all_scalar_binop_to_val_val_commutative!(impl Add<u128> for BigInt, add);
+
+impl Add<u32> for BigInt {
+    type Output = BigInt;
+
+    #[inline]
+    fn add(self, other: u32) -> BigInt {
+        match self.sign {
+            NoSign => From::from(other),
+            Plus => BigInt::from(self.data + other),
+            Minus => match self.data.cmp(&From::from(other)) {
+                Equal => Zero::zero(),
+                Less => BigInt::from(other - self.data),
+                Greater => -BigInt::from(self.data - other),
+            },
+        }
+    }
+}
+
+impl AddAssign<u32> for BigInt {
+    #[inline]
+    fn add_assign(&mut self, other: u32) {
+        let n = mem::replace(self, BigInt::zero());
+        *self = n + other;
+    }
+}
+
+impl Add<u64> for BigInt {
+    type Output = BigInt;
+
+    #[inline]
+    fn add(self, other: u64) -> BigInt {
+        match self.sign {
+            NoSign => From::from(other),
+            Plus => BigInt::from(self.data + other),
+            Minus => match self.data.cmp(&From::from(other)) {
+                Equal => Zero::zero(),
+                Less => BigInt::from(other - self.data),
+                Greater => -BigInt::from(self.data - other),
+            },
+        }
+    }
+}
+
+impl AddAssign<u64> for BigInt {
+    #[inline]
+    fn add_assign(&mut self, other: u64) {
+        let n = mem::replace(self, BigInt::zero());
+        *self = n + other;
+    }
+}
+
+impl Add<u128> for BigInt {
+    type Output = BigInt;
+
+    #[inline]
+    fn add(self, other: u128) -> BigInt {
+        match self.sign {
+            NoSign => BigInt::from(other),
+            Plus => BigInt::from(self.data + other),
+            Minus => match self.data.cmp(&From::from(other)) {
+                Equal => BigInt::zero(),
+                Less => BigInt::from(other - self.data),
+                Greater => -BigInt::from(self.data - other),
+            },
+        }
+    }
+}
+impl AddAssign<u128> for BigInt {
+    #[inline]
+    fn add_assign(&mut self, other: u128) {
+        let n = mem::replace(self, BigInt::zero());
+        *self = n + other;
+    }
+}
+
+forward_all_scalar_binop_to_val_val_commutative!(impl Add<i32> for BigInt, add);
+forward_all_scalar_binop_to_val_val_commutative!(impl Add<i64> for BigInt, add);
+forward_all_scalar_binop_to_val_val_commutative!(impl Add<i128> for BigInt, add);
+
+impl Add<i32> for BigInt {
+    type Output = BigInt;
+
+    #[inline]
+    fn add(self, other: i32) -> BigInt {
+        match other.checked_uabs() {
+            Positive(u) => self + u,
+            Negative(u) => self - u,
+        }
+    }
+}
+impl AddAssign<i32> for BigInt {
+    #[inline]
+    fn add_assign(&mut self, other: i32) {
+        match other.checked_uabs() {
+            Positive(u) => *self += u,
+            Negative(u) => *self -= u,
+        }
+    }
+}
+
+impl Add<i64> for BigInt {
+    type Output = BigInt;
+
+    #[inline]
+    fn add(self, other: i64) -> BigInt {
+        match other.checked_uabs() {
+            Positive(u) => self + u,
+            Negative(u) => self - u,
+        }
+    }
+}
+impl AddAssign<i64> for BigInt {
+    #[inline]
+    fn add_assign(&mut self, other: i64) {
+        match other.checked_uabs() {
+            Positive(u) => *self += u,
+            Negative(u) => *self -= u,
+        }
+    }
+}
+
+impl Add<i128> for BigInt {
+    type Output = BigInt;
+
+    #[inline]
+    fn add(self, other: i128) -> BigInt {
+        match other.checked_uabs() {
+            Positive(u) => self + u,
+            Negative(u) => self - u,
+        }
+    }
+}
+impl AddAssign<i128> for BigInt {
+    #[inline]
+    fn add_assign(&mut self, other: i128) {
+        match other.checked_uabs() {
+            Positive(u) => *self += u,
+            Negative(u) => *self -= u,
+        }
+    }
+}
+
+impl CheckedAdd for BigInt {
+    #[inline]
+    fn checked_add(&self, v: &BigInt) -> Option<BigInt> {
+        Some(self.add(v))
+    }
+}
+
+impl_sum_iter_type!(BigInt);

src/bigint/arbitrary.rs

@@ -0,0 +1,34 @@
+use super::{BigInt, Sign};
+
+use crate::std_alloc::Box;
+use crate::BigUint;
+
+#[cfg(feature = "quickcheck")]
+impl quickcheck::Arbitrary for BigInt {
+    fn arbitrary<G: quickcheck::Gen>(g: &mut G) -> Self {
+        let positive = bool::arbitrary(g);
+        let sign = if positive { Sign::Plus } else { Sign::Minus };
+        Self::from_biguint(sign, BigUint::arbitrary(g))
+    }
+
+    fn shrink(&self) -> Box<dyn Iterator<Item = Self>> {
+        let sign = self.sign();
+        let unsigned_shrink = self.data.shrink();
+        Box::new(unsigned_shrink.map(move |x| BigInt::from_biguint(sign, x)))
+    }
+}
+
+#[cfg(feature = "arbitrary")]
+impl arbitrary::Arbitrary for BigInt {
+    fn arbitrary(u: &mut arbitrary::Unstructured<'_>) -> arbitrary::Result<Self> {
+        let positive = bool::arbitrary(u)?;
+        let sign = if positive { Sign::Plus } else { Sign::Minus };
+        Ok(Self::from_biguint(sign, BigUint::arbitrary(u)?))
+    }
+
+    fn shrink(&self) -> Box<dyn Iterator<Item = Self>> {
+        let sign = self.sign();
+        let unsigned_shrink = self.data.shrink();
+        Box::new(unsigned_shrink.map(move |x| BigInt::from_biguint(sign, x)))
+    }
+}