Moved checked trait impls out of std::num

This follows the same pattern as the other numeric trait impls, and reduces the clutter in std::num.

Author: brendanzab

src/libstd/num/i16.rs

@@ -10,7 +10,8 @@
 
 //! Operations and constants for `i16`
 
-use num::BitCount;
+use num::{BitCount, CheckedAdd, CheckedSub, CheckedMul};
+use option::{Option, Some, None};
 use unstable::intrinsics;
 
 pub use self::generated::*;
@@ -30,3 +31,33 @@ impl BitCount for i16 {
     #[inline]
     fn trailing_zeros(&self) -> i16 { unsafe { intrinsics::cttz16(*self) } }
 }
+
+impl CheckedAdd for i16 {
+    #[inline]
+    fn checked_add(&self, v: &i16) -> Option<i16> {
+        unsafe {
+            let (x, y) = intrinsics::i16_add_with_overflow(*self, *v);
+            if y { None } else { Some(x) }
+        }
+    }
+}
+
+impl CheckedSub for i16 {
+    #[inline]
+    fn checked_sub(&self, v: &i16) -> Option<i16> {
+        unsafe {
+            let (x, y) = intrinsics::i16_sub_with_overflow(*self, *v);
+            if y { None } else { Some(x) }
+        }
+    }
+}
+
+impl CheckedMul for i16 {
+    #[inline]
+    fn checked_mul(&self, v: &i16) -> Option<i16> {
+        unsafe {
+            let (x, y) = intrinsics::i16_mul_with_overflow(*self, *v);
+            if y { None } else { Some(x) }
+        }
+    }
+}

src/libstd/num/i32.rs

@@ -10,7 +10,8 @@
 
 //! Operations and constants for `i32`
 
-use num::BitCount;
+use num::{BitCount, CheckedAdd, CheckedSub, CheckedMul};
+use option::{Option, Some, None};
 use unstable::intrinsics;
 
 pub use self::generated::*;
@@ -30,3 +31,33 @@ impl BitCount for i32 {
     #[inline]
     fn trailing_zeros(&self) -> i32 { unsafe { intrinsics::cttz32(*self) } }
 }
+
+impl CheckedAdd for i32 {
+    #[inline]
+    fn checked_add(&self, v: &i32) -> Option<i32> {
+        unsafe {
+            let (x, y) = intrinsics::i32_add_with_overflow(*self, *v);
+            if y { None } else { Some(x) }
+        }
+    }
+}
+
+impl CheckedSub for i32 {
+    #[inline]
+    fn checked_sub(&self, v: &i32) -> Option<i32> {
+        unsafe {
+            let (x, y) = intrinsics::i32_sub_with_overflow(*self, *v);
+            if y { None } else { Some(x) }
+        }
+    }
+}
+
+impl CheckedMul for i32 {
+    #[inline]
+    fn checked_mul(&self, v: &i32) -> Option<i32> {
+        unsafe {
+            let (x, y) = intrinsics::i32_mul_with_overflow(*self, *v);
+            if y { None } else { Some(x) }
+        }
+    }
+}

src/libstd/num/i64.rs

@@ -10,7 +10,8 @@
 
 //! Operations and constants for `i64`
 
-use num::BitCount;
+use num::{BitCount, CheckedAdd, CheckedSub, CheckedMul};
+use option::{Option, Some, None};
 use unstable::intrinsics;
 
 pub use self::generated::*;
@@ -30,3 +31,35 @@ impl BitCount for i64 {
     #[inline]
     fn trailing_zeros(&self) -> i64 { unsafe { intrinsics::cttz64(*self) } }
 }
+
+impl CheckedAdd for i64 {
+    #[inline]
+    fn checked_add(&self, v: &i64) -> Option<i64> {
+        unsafe {
+            let (x, y) = intrinsics::i64_add_with_overflow(*self, *v);
+            if y { None } else { Some(x) }
+        }
+    }
+}
+
+impl CheckedSub for i64 {
+    #[inline]
+    fn checked_sub(&self, v: &i64) -> Option<i64> {
+        unsafe {
+            let (x, y) = intrinsics::i64_sub_with_overflow(*self, *v);
+            if y { None } else { Some(x) }
+        }
+    }
+}
+
+// FIXME: #8449: should not be disabled on 32-bit
+#[cfg(target_word_size = "64")]
+impl CheckedMul for i64 {
+    #[inline]
+    fn checked_mul(&self, v: &i64) -> Option<i64> {
+        unsafe {
+            let (x, y) = intrinsics::i64_mul_with_overflow(*self, *v);
+            if y { None } else { Some(x) }
+        }
+    }
+}

src/libstd/num/i8.rs

@@ -10,7 +10,8 @@
 
 //! Operations and constants for `i8`
 
-use num::BitCount;
+use num::{BitCount, CheckedAdd, CheckedSub, CheckedMul};
+use option::{Option, Some, None};
 use unstable::intrinsics;
 
 pub use self::generated::*;
@@ -30,3 +31,33 @@ impl BitCount for i8 {
     #[inline]
     fn trailing_zeros(&self) -> i8 { unsafe { intrinsics::cttz8(*self) } }
 }
+
+impl CheckedAdd for i8 {
+    #[inline]
+    fn checked_add(&self, v: &i8) -> Option<i8> {
+        unsafe {
+            let (x, y) = intrinsics::i8_add_with_overflow(*self, *v);
+            if y { None } else { Some(x) }
+        }
+    }
+}
+
+impl CheckedSub for i8 {
+    #[inline]
+    fn checked_sub(&self, v: &i8) -> Option<i8> {
+        unsafe {
+            let (x, y) = intrinsics::i8_sub_with_overflow(*self, *v);
+            if y { None } else { Some(x) }
+        }
+    }
+}
+
+impl CheckedMul for i8 {
+    #[inline]
+    fn checked_mul(&self, v: &i8) -> Option<i8> {
+        unsafe {
+            let (x, y) = intrinsics::i8_mul_with_overflow(*self, *v);
+            if y { None } else { Some(x) }
+        }
+    }
+}

src/libstd/num/int.rs

@@ -12,7 +12,9 @@
 
 #[allow(non_uppercase_statics)];
 
-use num::BitCount;
+use num::{BitCount, CheckedAdd, CheckedSub, CheckedMul};
+use option::{Option, Some, None};
+use unstable::intrinsics;
 
 pub use self::generated::*;
 
@@ -51,6 +53,72 @@ impl BitCount for int {
     fn trailing_zeros(&self) -> int { (*self as i64).trailing_zeros() as int }
 }
 
+#[cfg(target_word_size = "32")]
+impl CheckedAdd for int {
+    #[inline]
+    fn checked_add(&self, v: &int) -> Option<int> {
+        unsafe {
+            let (x, y) = intrinsics::i32_add_with_overflow(*self as i32, *v as i32);
+            if y { None } else { Some(x as int) }
+        }
+    }
+}
+
+#[cfg(target_word_size = "64")]
+impl CheckedAdd for int {
+    #[inline]
+    fn checked_add(&self, v: &int) -> Option<int> {
+        unsafe {
+            let (x, y) = intrinsics::i64_add_with_overflow(*self as i64, *v as i64);
+            if y { None } else { Some(x as int) }
+        }
+    }
+}
+
+#[cfg(target_word_size = "32")]
+impl CheckedSub for int {
+    #[inline]
+    fn checked_sub(&self, v: &int) -> Option<int> {
+        unsafe {
+            let (x, y) = intrinsics::i32_sub_with_overflow(*self as i32, *v as i32);
+            if y { None } else { Some(x as int) }
+        }
+    }
+}
+
+#[cfg(target_word_size = "64")]
+impl CheckedSub for int {
+    #[inline]
+    fn checked_sub(&self, v: &int) -> Option<int> {
+        unsafe {
+            let (x, y) = intrinsics::i64_sub_with_overflow(*self as i64, *v as i64);
+            if y { None } else { Some(x as int) }
+        }
+    }
+}
+
+#[cfg(target_word_size = "32")]
+impl CheckedMul for int {
+    #[inline]
+    fn checked_mul(&self, v: &int) -> Option<int> {
+        unsafe {
+            let (x, y) = intrinsics::i32_mul_with_overflow(*self as i32, *v as i32);
+            if y { None } else { Some(x as int) }
+        }
+    }
+}
+
+#[cfg(target_word_size = "64")]
+impl CheckedMul for int {
+    #[inline]
+    fn checked_mul(&self, v: &int) -> Option<int> {
+        unsafe {
+            let (x, y) = intrinsics::i64_mul_with_overflow(*self as i64, *v as i64);
+            if y { None } else { Some(x as int) }
+        }
+    }
+}
+
 /// Returns `base` raised to the power of `exponent`
 pub fn pow(base: int, exponent: uint) -> int {
     if exponent == 0u {