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| author | Manish Goregaokar <manishsmail@gmail.com> | 2021-10-06 12:33:13 -0700 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2021-10-06 12:33:13 -0700 |
| commit | 3209582a87f7b8e098bac67f66ed58d8d5840dee (patch) | |
| tree | dd17f17506a04ccb9167e7d3b6b2bb8cbf1a6a86 /library/std/src | |
| parent | d7539a6af09e5889ed9bcb8b49571b7a59c32e65 (diff) | |
| parent | 47edde1086412b36e9efd6098b191ec15a2a760a (diff) | |
Rollup merge of #87601 - a1phyr:feature_uint_add_signed, r=kennytm
Add functions to add unsigned and signed integers
This PR adds methods to unsigned integers to add signed integers with good overflow semantics under `#![feature(mixed_integer_ops)]`.
The added API is:
```rust
// `uX` is `u8`, `u16`, `u32`, `u64`,`u128`, `usize`
impl uX {
pub const fn checked_add_signed(self, iX) -> Option<Self>;
pub const fn overflowing_add_signed(self, iX) -> (Self, bool);
pub const fn saturating_add_signed(self, iX) -> Self;
pub const fn wrapping_add_signed(self, iX) -> Self;
}
impl iX {
pub const fn checked_add_unsigned(self, uX) -> Option<Self>;
pub const fn overflowing_add_unsigned(self, uX) -> (Self, bool);
pub const fn saturating_add_unsigned(self, uX) -> Self;
pub const fn wrapping_add_unsigned(self, uX) -> Self;
pub const fn checked_sub_unsigned(self, uX) -> Option<Self>;
pub const fn overflowing_sub_unsigned(self, uX) -> (Self, bool);
pub const fn saturating_sub_unsigned(self, uX) -> Self;
pub const fn wrapping_sub_unsigned(self, uX) -> Self;
}
```
Maybe it would be interesting to also have `add_signed` that panics in debug and wraps in release ?
Diffstat (limited to 'library/std/src')
| -rw-r--r-- | library/std/src/io/cursor.rs | 7 | ||||
| -rw-r--r-- | library/std/src/lib.rs | 1 |
2 files changed, 2 insertions, 6 deletions
diff --git a/library/std/src/io/cursor.rs b/library/std/src/io/cursor.rs index 25cc5e67ad1..980b2531192 100644 --- a/library/std/src/io/cursor.rs +++ b/library/std/src/io/cursor.rs @@ -292,12 +292,7 @@ where SeekFrom::End(n) => (self.inner.as_ref().len() as u64, n), SeekFrom::Current(n) => (self.pos, n), }; - let new_pos = if offset >= 0 { - base_pos.checked_add(offset as u64) - } else { - base_pos.checked_sub((offset.wrapping_neg()) as u64) - }; - match new_pos { + match base_pos.checked_add_signed(offset) { Some(n) => { self.pos = n; Ok(self.pos) diff --git a/library/std/src/lib.rs b/library/std/src/lib.rs index 0ba4e85886c..a7516bf4ffd 100644 --- a/library/std/src/lib.rs +++ b/library/std/src/lib.rs @@ -297,6 +297,7 @@ #![feature(maybe_uninit_slice)] #![feature(maybe_uninit_uninit_array)] #![feature(min_specialization)] +#![feature(mixed_integer_ops)] #![cfg_attr(not(bootstrap), feature(must_not_suspend))] #![feature(needs_panic_runtime)] #![feature(negative_impls)] |