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| author | Ixrec <ericrhitchcock@gmail.com> | 2017-09-17 17:03:56 +0100 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2017-09-17 17:03:56 +0100 |
| commit | 2633b85ab2c89822d2c227fc9e81c6ec1c0ed9b6 (patch) | |
| tree | 153dd6766670875f2940c36f8e057a8bde27eae4 | |
| parent | ef227f5ffe438783db0add58208d79dd84158c06 (diff) | |
| download | rust-2633b85ab2c89822d2c227fc9e81c6ec1c0ed9b6.tar.gz rust-2633b85ab2c89822d2c227fc9e81c6ec1c0ed9b6.zip | |
Replace str's transmute() calls with pointer casts
After the following conversation in #rust-lang: ``` [14:43:50] <Ixrec> TIL the implementation of from_utf_unchecked is literally just "mem::transmute(x)" [14:43:59] <Ixrec> no wonder people keep saying transmute is overpowered [15:15:30] <eddyb> Ixrec: it should be a pointer cast lol [15:15:46] <eddyb> unless it doesn't let you [16:50:34] <Ixrec> https://play.rust-lang.org/?gist=d1e6b629ad9ec1baf64ce261c63845e6&version=stable seems like it does let me [16:52:35] <eddyb> Ixrec: yeah that's the preferred impl [16:52:46] <eddyb> Ixrec: it just wasn't in 1.0 [16:52:50] <eddyb> IIRC [16:53:00] <eddyb> (something something fat pointers) ``` Since I already wrote half of the preferred impls in the playground, might as well make an actual PR.
| -rw-r--r-- | src/libcore/str/mod.rs | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/src/libcore/str/mod.rs b/src/libcore/str/mod.rs index d4fef45ae4e..60f3640446c 100644 --- a/src/libcore/str/mod.rs +++ b/src/libcore/str/mod.rs @@ -404,7 +404,7 @@ unsafe fn from_raw_parts_mut<'a>(p: *mut u8, len: usize) -> &'a mut str { #[inline] #[stable(feature = "rust1", since = "1.0.0")] pub unsafe fn from_utf8_unchecked(v: &[u8]) -> &str { - mem::transmute(v) + &*(v as *const [u8] as *const str) } /// Converts a slice of bytes to a string slice without checking @@ -429,7 +429,7 @@ pub unsafe fn from_utf8_unchecked(v: &[u8]) -> &str { #[inline] #[stable(feature = "str_mut_extras", since = "1.20.0")] pub unsafe fn from_utf8_unchecked_mut(v: &mut [u8]) -> &mut str { - mem::transmute(v) + &*(v as *mut [u8] as *mut str) } #[stable(feature = "rust1", since = "1.0.0")] @@ -2447,12 +2447,12 @@ impl StrExt for str { #[inline] fn as_bytes(&self) -> &[u8] { - unsafe { mem::transmute(self) } + unsafe { &*(self as *const str as *const [u8]) } } #[inline] unsafe fn as_bytes_mut(&mut self) -> &mut [u8] { - mem::transmute(self) + &mut *(self as *mut str as *mut [u8]) } fn find<'a, P: Pattern<'a>>(&'a self, pat: P) -> Option<usize> { |