arrow-buffer: implement num-traits numeric operations

arrow-buffer/src/bigint/mod.rs

@@ -18,7 +18,11 @@
 use crate::arith::derive_arith;
 use crate::bigint::div::div_rem;
 use num_bigint::BigInt;
-use num_traits::{FromPrimitive, ToPrimitive, cast::AsPrimitive};
+use num_traits::{
+    Bounded, CheckedAdd, CheckedDiv, CheckedMul, CheckedNeg, CheckedRem, CheckedSub, FromPrimitive,
+    Num, One, Signed, ToPrimitive, WrappingAdd, WrappingMul, WrappingNeg, WrappingSub, Zero,
+    cast::AsPrimitive,
+};
 use std::cmp::Ordering;
 use std::num::ParseIntError;
 use std::ops::{BitAnd, BitOr, BitXor, Neg, Shl, Shr};
@@ -869,6 +873,137 @@ impl ToPrimitive for i256 {
     }
 }
 
+// num_traits checked implementations
+
+impl CheckedNeg for i256 {
+    fn checked_neg(&self) -> Option<Self> {
+        (*self).checked_neg()
+    }
+}
+
+impl CheckedAdd for i256 {
+    fn checked_add(&self, v: &i256) -> Option<Self> {
+        (*self).checked_add(*v)
+    }
+}
+
+impl CheckedSub for i256 {
+    fn checked_sub(&self, v: &i256) -> Option<Self> {
+        (*self).checked_sub(*v)
+    }
+}
+
+impl CheckedDiv for i256 {
+    fn checked_div(&self, v: &i256) -> Option<Self> {
+        (*self).checked_div(*v)
+    }
+}
+
+impl CheckedMul for i256 {
+    fn checked_mul(&self, v: &i256) -> Option<Self> {
+        (*self).checked_mul(*v)
+    }
+}
+
+impl CheckedRem for i256 {
+    fn checked_rem(&self, v: &i256) -> Option<Self> {
+        (*self).checked_rem(*v)
+    }
+}
+
+impl WrappingAdd for i256 {
+    fn wrapping_add(&self, v: &Self) -> Self {
+        (*self).wrapping_add(*v)
+    }
+}
+
+impl WrappingSub for i256 {
+    fn wrapping_sub(&self, v: &Self) -> Self {
+        (*self).wrapping_sub(*v)
+    }
+}
+
+impl WrappingMul for i256 {
+    fn wrapping_mul(&self, v: &Self) -> Self {
+        (*self).wrapping_mul(*v)
+    }
+}
+
+impl WrappingNeg for i256 {
+    fn wrapping_neg(&self) -> Self {
+        (*self).wrapping_neg()
+    }
+}
+
+impl Zero for i256 {
+    fn zero() -> Self {
+        i256::ZERO
+    }
+
+    fn is_zero(&self) -> bool {
+        *self == i256::ZERO
+    }
+}
+
+impl One for i256 {
+    fn one() -> Self {
+        i256::ONE
+    }
+
+    fn is_one(&self) -> bool {
+        *self == i256::ONE
+    }
+}
+
+impl Num for i256 {
+    type FromStrRadixErr = ParseI256Error;
+
+    fn from_str_radix(str: &str, radix: u32) -> Result<Self, Self::FromStrRadixErr> {
+        if radix == 10 {
+            str.parse()
+        } else {
+            // Parsing from non-10 baseseeÎ is not supported
+            Err(ParseI256Error {})
+        }
+    }
+}
+
+impl Signed for i256 {
+    fn abs(&self) -> Self {
+        self.wrapping_abs()
+    }
+
+    fn abs_sub(&self, other: &Self) -> Self {
+        if self > other {
+            self.wrapping_sub(other)
+        } else {
+            i256::ZERO
+        }
+    }
+
+    fn signum(&self) -> Self {
+        (*self).signum()
+    }
+
+    fn is_positive(&self) -> bool {
+        (*self).is_positive()
+    }
+
+    fn is_negative(&self) -> bool {
+        (*self).is_negative()
+    }
+}
+
+impl Bounded for i256 {
+    fn min_value() -> Self {
+        i256::MIN
+    }
+
+    fn max_value() -> Self {
+        i256::MAX
+    }
+}
+
 #[cfg(all(test, not(miri)))] // llvm.x86.subborrow.64 not supported by MIRI
 mod tests {
     use super::*;
@@ -1337,6 +1472,83 @@ mod tests {
         assert!(out.is_finite() && out.is_sign_negative());
     }
 
+    #[test]
+    fn test_num_traits() {
+        let value = i256::from_i128(-5);
+        assert_eq!(
+            <i256 as CheckedNeg>::checked_neg(&value),
+            Some(i256::from(5))
+        );
+
+        assert_eq!(
+            <i256 as CheckedAdd>::checked_add(&value, &value),
+            Some(i256::from(-10))
+        );
+
+        assert_eq!(
+            <i256 as CheckedSub>::checked_sub(&value, &value),
+            Some(i256::from(0))
+        );
+
+        assert_eq!(
+            <i256 as CheckedMul>::checked_mul(&value, &value),
+            Some(i256::from(25))
+        );
+
+        assert_eq!(
+            <i256 as CheckedDiv>::checked_div(&value, &value),
+            Some(i256::from(1))
+        );
+
+        assert_eq!(
+            <i256 as CheckedRem>::checked_rem(&value, &value),
+            Some(i256::from(0))
+        );
+
+        assert_eq!(
+            <i256 as WrappingAdd>::wrapping_add(&value, &value),
+            i256::from(-10)
+        );
+
+        assert_eq!(
+            <i256 as WrappingSub>::wrapping_sub(&value, &value),
+            i256::from(0)
+        );
+
+        assert_eq!(
+            <i256 as WrappingMul>::wrapping_mul(&value, &value),
+            i256::from(25)
+        );
+
+        assert_eq!(<i256 as WrappingNeg>::wrapping_neg(&value), i256::from(5));
+
+        // A single check for wrapping behavior, rely on trait implementation for others
+        let result = <i256 as WrappingAdd>::wrapping_add(&i256::MAX, &i256::ONE);
+        assert_eq!(result, i256::MIN);
+
+        assert_eq!(<i256 as Signed>::abs(&value), i256::from(5));
+
+        assert_eq!(<i256 as One>::one(), i256::from(1));
+        assert_eq!(<i256 as Zero>::zero(), i256::from(0));
+
+        assert_eq!(<i256 as Bounded>::min_value(), i256::MIN);
+        assert_eq!(<i256 as Bounded>::max_value(), i256::MAX);
+    }
+
+    #[test]
+    fn test_numtraits_from_str_radix() {
+        assert_eq!(
+            i256::from_str_radix("123456789", 10).expect("parsed"),
+            i256::from(123456789)
+        );
+        assert_eq!(
+            i256::from_str_radix("0", 10).expect("parsed"),
+            i256::from(0)
+        );
+        assert!(i256::from_str_radix("abc", 10).is_err());
+        assert!(i256::from_str_radix("0", 16).is_err());
+    }
+
     #[test]
     fn test_leading_zeros() {
         // Without high part