Auto merge of #24420 - pnkfelix:oflo-api, r=alexcrichton

Fill in missing parts of Integer overflow API 

See todo list at #22020

src/libcore/num/mod.rs

@@ -1219,6 +1219,66 @@ pub fn wrapping_mul(self, rhs: $T) -> $T {
             }
         }
 
+        /// Wrapping (modular) division. Computes `floor(self / other)`,
+        /// wrapping around at the boundary of the type.
+        ///
+        /// The only case where such wrapping can occur is when one
+        /// divides `MIN / -1` on a signed type (where `MIN` is the
+        /// negative minimal value for the type); this is equivalent
+        /// to `-MIN`, a positive value that is too large to represent
+        /// in the type. In such a case, this function returns `MIN`
+        /// itself..
+        #[unstable(feature = "core", since = "1.0.0")]
+        #[inline(always)]
+        pub fn wrapping_div(self, rhs: $T) -> $T {
+            self.overflowing_div(rhs).0
+        }
+
+        /// Wrapping (modular) remainder. Computes `self % other`,
+        /// wrapping around at the boundary of the type.
+        ///
+        /// Such wrap-around never actually occurs mathematically;
+        /// implementation artifacts make `x % y` illegal for `MIN /
+        /// -1` on a signed type illegal (where `MIN` is the negative
+        /// minimal value). In such a case, this function returns `0`.
+        #[unstable(feature = "core", since = "1.0.0")]
+        #[inline(always)]
+        pub fn wrapping_rem(self, rhs: $T) -> $T {
+            self.overflowing_rem(rhs).0
+        }
+
+        /// Wrapping (modular) negation. Computes `-self`,
+        /// wrapping around at the boundary of the type.
+        ///
+        /// The only case where such wrapping can occur is when one
+        /// negates `MIN` on a signed type (where `MIN` is the
+        /// negative minimal value for the type); this is a positive
+        /// value that is too large to represent in the type. In such
+        /// a case, this function returns `MIN` itself.
+        #[unstable(feature = "core", since = "1.0.0")]
+        #[inline(always)]
+        pub fn wrapping_neg(self) -> $T {
+            self.overflowing_neg().0
+        }
+
+        /// Panic-free bitwise shift-left; yields `self << mask(rhs)`,
+        /// where `mask` removes any high-order bits of `rhs` that
+        /// would cause the shift to exceed the bitwidth of the type.
+        #[unstable(feature = "core", since = "1.0.0")]
+        #[inline(always)]
+        pub fn wrapping_shl(self, rhs: u32) -> $T {
+            self.overflowing_shl(rhs).0
+        }
+
+        /// Panic-free bitwise shift-left; yields `self >> mask(rhs)`,
+        /// where `mask` removes any high-order bits of `rhs` that
+        /// would cause the shift to exceed the bitwidth of the type.
+        #[unstable(feature = "core", since = "1.0.0")]
+        #[inline(always)]
+        pub fn wrapping_shr(self, rhs: u32) -> $T {
+            self.overflowing_shr(rhs).0
+        }
+
         /// Raises self to the power of `exp`, using exponentiation by squaring.
         ///
         /// # Examples
@@ -1739,6 +1799,66 @@ pub fn wrapping_mul(self, rhs: $T) -> $T {
             }
         }
 
+        /// Wrapping (modular) division. Computes `floor(self / other)`,
+        /// wrapping around at the boundary of the type.
+        ///
+        /// The only case where such wrapping can occur is when one
+        /// divides `MIN / -1` on a signed type (where `MIN` is the
+        /// negative minimal value for the type); this is equivalent
+        /// to `-MIN`, a positive value that is too large to represent
+        /// in the type. In such a case, this function returns `MIN`
+        /// itself..
+        #[unstable(feature = "core", since = "1.0.0")]
+        #[inline(always)]
+        pub fn wrapping_div(self, rhs: $T) -> $T {
+            self.overflowing_div(rhs).0
+        }
+
+        /// Wrapping (modular) remainder. Computes `self % other`,
+        /// wrapping around at the boundary of the type.
+        ///
+        /// Such wrap-around never actually occurs mathematically;
+        /// implementation artifacts make `x % y` illegal for `MIN /
+        /// -1` on a signed type illegal (where `MIN` is the negative
+        /// minimal value). In such a case, this function returns `0`.
+        #[unstable(feature = "core", since = "1.0.0")]
+        #[inline(always)]
+        pub fn wrapping_rem(self, rhs: $T) -> $T {
+            self.overflowing_rem(rhs).0
+        }
+
+        /// Wrapping (modular) negation. Computes `-self`,
+        /// wrapping around at the boundary of the type.
+        ///
+        /// The only case where such wrapping can occur is when one
+        /// negates `MIN` on a signed type (where `MIN` is the
+        /// negative minimal value for the type); this is a positive
+        /// value that is too large to represent in the type. In such
+        /// a case, this function returns `MIN` itself.
+        #[unstable(feature = "core", since = "1.0.0")]
+        #[inline(always)]
+        pub fn wrapping_neg(self) -> $T {
+            self.overflowing_neg().0
+        }
+
+        /// Panic-free bitwise shift-left; yields `self << mask(rhs)`,
+        /// where `mask` removes any high-order bits of `rhs` that
+        /// would cause the shift to exceed the bitwidth of the type.
+        #[unstable(feature = "core", since = "1.0.0")]
+        #[inline(always)]
+        pub fn wrapping_shl(self, rhs: u32) -> $T {
+            self.overflowing_shl(rhs).0
+        }
+
+        /// Panic-free bitwise shift-left; yields `self >> mask(rhs)`,
+        /// where `mask` removes any high-order bits of `rhs` that
+        /// would cause the shift to exceed the bitwidth of the type.
+        #[unstable(feature = "core", since = "1.0.0")]
+        #[inline(always)]
+        pub fn wrapping_shr(self, rhs: u32) -> $T {
+            self.overflowing_shr(rhs).0
+        }
+
         /// Raises self to the power of `exp`, using exponentiation by squaring.
         ///
         /// # Examples

src/libcore/num/wrapping.rs

@@ -48,6 +48,7 @@ pub trait OverflowingOps {
 
     fn overflowing_div(self, rhs: Self) -> (Self, bool);
     fn overflowing_rem(self, rhs: Self) -> (Self, bool);
+    fn overflowing_neg(self) -> (Self, bool);
 
     fn overflowing_shl(self, rhs: u32) -> (Self, bool);
     fn overflowing_shr(self, rhs: u32) -> (Self, bool);
@@ -231,7 +232,7 @@ fn overflowing_mul(self, rhs: $t) -> ($t, bool) {
             #[inline(always)]
             fn overflowing_div(self, rhs: $t) -> ($t, bool) {
                 if self == $t::MIN && rhs == -1 {
-                    (1, true)
+                    (self, true)
                 } else {
                     (self/rhs, false)
                 }
@@ -255,6 +256,15 @@ fn overflowing_shr(self, rhs: u32) -> ($t, bool) {
                 (self >> (rhs & self::shift_max::$t),
                  (rhs > self::shift_max::$t))
             }
+
+            #[inline(always)]
+            fn overflowing_neg(self) -> ($t, bool) {
+                if self == $t::MIN {
+                    ($t::MIN, true)
+                } else {
+                    (-self, false)
+                }
+            }
         }
     )*)
 }
@@ -300,6 +310,11 @@ fn overflowing_shr(self, rhs: u32) -> ($t, bool) {
                 (self >> (rhs & self::shift_max::$t),
                  (rhs > self::shift_max::$t))
             }
+
+            #[inline(always)]
+            fn overflowing_neg(self) -> ($t, bool) {
+                ((!self).wrapping_add(1), true)
+            }
         }
     )*)
 }
@@ -341,6 +356,11 @@ fn overflowing_rem(self, rhs: usize) -> (usize, bool) {
         (r as usize, f)
     }
     #[inline(always)]
+    fn overflowing_neg(self) -> (usize, bool) {
+        let (r, f) = (self as u64).overflowing_neg();
+        (r as usize, f)
+    }
+    #[inline(always)]
     fn overflowing_shl(self, rhs: u32) -> (usize, bool) {
         let (r, f) = (self as u64).overflowing_shl(rhs);
         (r as usize, f)
@@ -386,6 +406,11 @@ fn overflowing_rem(self, rhs: usize) -> (usize, bool) {
         (r as usize, f)
     }
     #[inline(always)]
+    fn overflowing_neg(self) -> (usize, bool) {
+        let (r, f) = (self as u32).overflowing_neg();
+        (r as usize, f)
+    }
+    #[inline(always)]
     fn overflowing_shl(self, rhs: u32) -> (usize, bool) {
         let (r, f) = (self as u32).overflowing_shl(rhs);
         (r as usize, f)
@@ -431,6 +456,11 @@ fn overflowing_rem(self, rhs: isize) -> (isize, bool) {
         (r as isize, f)
     }
     #[inline(always)]
+    fn overflowing_neg(self) -> (isize, bool) {
+        let (r, f) = (self as i64).overflowing_neg();
+        (r as isize, f)
+    }
+    #[inline(always)]
     fn overflowing_shl(self, rhs: u32) -> (isize, bool) {
         let (r, f) = (self as i64).overflowing_shl(rhs);
         (r as isize, f)
@@ -476,6 +506,11 @@ fn overflowing_rem(self, rhs: isize) -> (isize, bool) {
         (r as isize, f)
     }
     #[inline(always)]
+    fn overflowing_neg(self) -> (isize, bool) {
+        let (r, f) = (self as i32).overflowing_neg();
+        (r as isize, f)
+    }
+    #[inline(always)]
     fn overflowing_shl(self, rhs: u32) -> (isize, bool) {
         let (r, f) = (self as i32).overflowing_shl(rhs);
         (r as isize, f)

src/test/run-pass/wrapping-int-api.rs

@@ -0,0 +1,236 @@
+// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![feature(core)]
+
+// Test inherent wrapping_* methods for {i,u}{size,8,16,32,64}.
+
+use std::{i8, i16, i32, i64, isize};
+use std::{u8, u16, u32, u64, usize};
+
+fn main() {
+    assert_eq!(   i8::MAX.wrapping_add(1),    i8::MIN);
+    assert_eq!(  i16::MAX.wrapping_add(1),   i16::MIN);
+    assert_eq!(  i32::MAX.wrapping_add(1),   i32::MIN);
+    assert_eq!(  i64::MAX.wrapping_add(1),   i64::MIN);
+    assert_eq!(isize::MAX.wrapping_add(1), isize::MIN);
+
+    assert_eq!(   i8::MIN.wrapping_sub(1),    i8::MAX);
+    assert_eq!(  i16::MIN.wrapping_sub(1),   i16::MAX);
+    assert_eq!(  i32::MIN.wrapping_sub(1),   i32::MAX);
+    assert_eq!(  i64::MIN.wrapping_sub(1),   i64::MAX);
+    assert_eq!(isize::MIN.wrapping_sub(1), isize::MAX);
+
+    assert_eq!(   u8::MAX.wrapping_add(1),    u8::MIN);
+    assert_eq!(  u16::MAX.wrapping_add(1),   u16::MIN);
+    assert_eq!(  u32::MAX.wrapping_add(1),   u32::MIN);
+    assert_eq!(  u64::MAX.wrapping_add(1),   u64::MIN);
+    assert_eq!(usize::MAX.wrapping_add(1), usize::MIN);
+
+    assert_eq!(   u8::MIN.wrapping_sub(1),    u8::MAX);
+    assert_eq!(  u16::MIN.wrapping_sub(1),   u16::MAX);
+    assert_eq!(  u32::MIN.wrapping_sub(1),   u32::MAX);
+    assert_eq!(  u64::MIN.wrapping_sub(1),   u64::MAX);
+    assert_eq!(usize::MIN.wrapping_sub(1), usize::MAX);
+
+    assert_eq!((0xfe_u8 as i8).wrapping_mul(16),
+               (0xe0_u8 as i8));
+    assert_eq!((0xfedc_u16 as i16).wrapping_mul(16),
+               (0xedc0_u16 as i16));
+    assert_eq!((0xfedc_ba98_u32 as i32).wrapping_mul(16),
+               (0xedcb_a980_u32 as i32));
+    assert_eq!((0xfedc_ba98_7654_3217_u64 as i64).wrapping_mul(16),
+               (0xedcb_a987_6543_2170_u64 as i64));
+
+    match () {
+        #[cfg(target_pointer_width = "32")]
+        () => {
+            assert_eq!((0xfedc_ba98_u32 as isize).wrapping_mul(16),
+                       (0xedcb_a980_u32 as isize));
+        }
+        #[cfg(target_pointer_width = "64")]
+        () => {
+            assert_eq!((0xfedc_ba98_7654_3217_u64 as isize).wrapping_mul(16),
+                       (0xedcb_a987_6543_2170_u64 as isize));
+        }
+    }
+
+    assert_eq!((0xfe as u8).wrapping_mul(16),
+               (0xe0 as u8));
+    assert_eq!((0xfedc as u16).wrapping_mul(16),
+               (0xedc0 as u16));
+    assert_eq!((0xfedc_ba98 as u32).wrapping_mul(16),
+               (0xedcb_a980 as u32));
+    assert_eq!((0xfedc_ba98_7654_3217 as u64).wrapping_mul(16),
+               (0xedcb_a987_6543_2170 as u64));
+
+    match () {
+        #[cfg(target_pointer_width = "32")]
+        () => {
+            assert_eq!((0xfedc_ba98 as usize).wrapping_mul(16),
+                       (0xedcb_a980 as usize));
+        }
+        #[cfg(target_pointer_width = "64")]
+        () => {
+            assert_eq!((0xfedc_ba98_7654_3217 as usize).wrapping_mul(16),
+                       (0xedcb_a987_6543_2170 as usize));
+        }
+    }
+
+    macro_rules! check_mul_no_wrap {
+        ($e:expr, $f:expr) => { assert_eq!(($e).wrapping_mul($f), ($e) * $f); }
+    }
+    macro_rules! check_mul_wraps {
+        ($e:expr, $f:expr) => { assert_eq!(($e).wrapping_mul($f), $e); }
+    }
+
+    check_mul_no_wrap!(0xfe_u8 as i8, -1);
+    check_mul_no_wrap!(0xfedc_u16 as i16, -1);
+    check_mul_no_wrap!(0xfedc_ba98_u32 as i32, -1);
+    check_mul_no_wrap!(0xfedc_ba98_7654_3217_u64 as i64, -1);
+    check_mul_no_wrap!(0xfedc_ba98_7654_3217_u64 as u64 as isize, -1);
+
+    check_mul_no_wrap!(0xfe_u8 as i8, -2);
+    check_mul_no_wrap!(0xfedc_u16 as i16, -2);
+    check_mul_no_wrap!(0xfedc_ba98_u32 as i32, -2);
+    check_mul_no_wrap!(0xfedc_ba98_7654_3217_u64 as i64, -2);
+    check_mul_no_wrap!(0xfedc_ba98_fedc_ba98_u64 as u64 as isize, -2);
+
+    check_mul_no_wrap!(0xfe_u8 as i8, 2);
+    check_mul_no_wrap!(0xfedc_u16 as i16, 2);
+    check_mul_no_wrap!(0xfedc_ba98_u32 as i32, 2);
+    check_mul_no_wrap!(0xfedc_ba98_7654_3217_u64 as i64, 2);
+    check_mul_no_wrap!(0xfedc_ba98_fedc_ba98_u64 as u64 as isize, 2);
+
+    check_mul_wraps!(0x80_u8 as i8, -1);
+    check_mul_wraps!(0x8000_u16 as i16, -1);
+    check_mul_wraps!(0x8000_0000_u32 as i32, -1);
+    check_mul_wraps!(0x8000_0000_0000_0000_u64 as i64, -1);
+    match () {
+        #[cfg(target_pointer_width = "32")]
+        () => {
+            check_mul_wraps!(0x8000_0000_u32 as isize, -1);
+        }
+        #[cfg(target_pointer_width = "64")]
+        () => {
+            check_mul_wraps!(0x8000_0000_0000_0000_u64 as isize, -1);
+        }
+    }
+
+    macro_rules! check_div_no_wrap {
+        ($e:expr, $f:expr) => { assert_eq!(($e).wrapping_div($f), ($e) / $f); }
+    }
+    macro_rules! check_div_wraps {
+        ($e:expr, $f:expr) => { assert_eq!(($e).wrapping_div($f), $e); }
+    }
+
+    check_div_no_wrap!(0xfe_u8 as i8, -1);
+    check_div_no_wrap!(0xfedc_u16 as i16, -1);
+    check_div_no_wrap!(0xfedc_ba98_u32 as i32, -1);
+    check_div_no_wrap!(0xfedc_ba98_7654_3217_u64 as i64, -1);
+    check_div_no_wrap!(0xfedc_ba98_7654_3217_u64 as u64 as isize, -1);
+
+    check_div_no_wrap!(0xfe_u8 as i8, -2);
+    check_div_no_wrap!(0xfedc_u16 as i16, -2);
+    check_div_no_wrap!(0xfedc_ba98_u32 as i32, -2);
+    check_div_no_wrap!(0xfedc_ba98_7654_3217_u64 as i64, -2);
+    check_div_no_wrap!(0xfedc_ba98_7654_3217_u64 as u64 as isize, -2);
+
+    check_div_no_wrap!(0xfe_u8 as i8, 2);
+    check_div_no_wrap!(0xfedc_u16 as i16, 2);
+    check_div_no_wrap!(0xfedc_ba98_u32 as i32, 2);
+    check_div_no_wrap!(0xfedc_ba98_7654_3217_u64 as i64, 2);
+    check_div_no_wrap!(0xfedc_ba98_7654_3217_u64 as u64 as isize, 2);
+
+    check_div_wraps!(-128 as i8, -1);
+    check_div_wraps!(0x8000_u16 as i16, -1);
+    check_div_wraps!(0x8000_0000_u32 as i32, -1);
+    check_div_wraps!(0x8000_0000_0000_0000_u64 as i64, -1);
+    match () {
+        #[cfg(target_pointer_width = "32")]
+        () => {
+            check_div_wraps!(0x8000_0000_u32 as isize, -1);
+        }
+        #[cfg(target_pointer_width = "64")]
+        () => {
+            check_div_wraps!(0x8000_0000_0000_0000_u64 as isize, -1);
+        }
+    }
+
+
+    macro_rules! check_rem_no_wrap {
+        ($e:expr, $f:expr) => { assert_eq!(($e).wrapping_rem($f), ($e) % $f); }
+    }
+    macro_rules! check_rem_wraps {
+        ($e:expr, $f:expr) => { assert_eq!(($e).wrapping_rem($f), 0); }
+    }
+
+    check_rem_no_wrap!(0xfe_u8 as i8, -1);
+    check_rem_no_wrap!(0xfedc_u16 as i16, -1);
+    check_rem_no_wrap!(0xfedc_ba98_u32 as i32, -1);
+    check_rem_no_wrap!(0xfedc_ba98_7654_3217_u64 as i64, -1);
+    check_rem_no_wrap!(0xfedc_ba98_7654_3217_u64 as u64 as isize, -1);
+
+    check_rem_no_wrap!(0xfe_u8 as i8, -2);
+    check_rem_no_wrap!(0xfedc_u16 as i16, -2);
+    check_rem_no_wrap!(0xfedc_ba98_u32 as i32, -2);
+    check_rem_no_wrap!(0xfedc_ba98_7654_3217_u64 as i64, -2);
+    check_rem_no_wrap!(0xfedc_ba98_7654_3217_u64 as u64 as isize, -2);
+
+    check_rem_no_wrap!(0xfe_u8 as i8, 2);
+    check_rem_no_wrap!(0xfedc_u16 as i16, 2);
+    check_rem_no_wrap!(0xfedc_ba98_u32 as i32, 2);
+    check_rem_no_wrap!(0xfedc_ba98_7654_3217_u64 as i64, 2);
+    check_rem_no_wrap!(0xfedc_ba98_7654_3217_u64 as u64 as isize, 2);
+
+    check_rem_wraps!(0x80_u8 as i8, -1);
+    check_rem_wraps!(0x8000_u16 as i16, -1);
+    check_rem_wraps!(0x8000_0000_u32 as i32, -1);
+    check_rem_wraps!(0x8000_0000_0000_0000_u64 as i64, -1);
+    match () {
+        #[cfg(target_pointer_width = "32")]
+        () => {
+            check_rem_wraps!(0x8000_0000_u32 as isize, -1);
+        }
+        #[cfg(target_pointer_width = "64")]
+        () => {
+            check_rem_wraps!(0x8000_0000_0000_0000_u64 as isize, -1);
+        }
+    }
+
+    macro_rules! check_neg_no_wrap {
+        ($e:expr) => { assert_eq!(($e).wrapping_neg(), -($e)); }
+    }
+    macro_rules! check_neg_wraps {
+        ($e:expr) => { assert_eq!(($e).wrapping_neg(),  ($e)); }
+    }
+
+    check_neg_no_wrap!(0xfe_u8 as i8);
+    check_neg_no_wrap!(0xfedc_u16 as i16);
+    check_neg_no_wrap!(0xfedc_ba98_u32 as i32);
+    check_neg_no_wrap!(0xfedc_ba98_7654_3217_u64 as i64);
+    check_neg_no_wrap!(0xfedc_ba98_7654_3217_u64 as u64 as isize);
+
+    check_neg_wraps!(0x80_u8 as i8);
+    check_neg_wraps!(0x8000_u16 as i16);
+    check_neg_wraps!(0x8000_0000_u32 as i32);
+    check_neg_wraps!(0x8000_0000_0000_0000_u64 as i64);
+    match () {
+        #[cfg(target_pointer_width = "32")]
+        () => {
+            check_neg_wraps!(0x8000_0000_u32 as isize);
+        }
+        #[cfg(target_pointer_width = "64")]
+        () => {
+            check_neg_wraps!(0x8000_0000_0000_0000_u64 as isize);
+        }
+    }
+
+}