mirror of https://github.com/rust-lang/rust.git
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.
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@ -404,7 +404,7 @@ unsafe fn from_raw_parts_mut<'a>(p: *mut u8, len: usize) -> &'a mut str {
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#[inline]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub unsafe fn from_utf8_unchecked(v: &[u8]) -> &str {
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mem::transmute(v)
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&*(v as *const [u8] as *const str)
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}
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/// Converts a slice of bytes to a string slice without checking
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@ -429,7 +429,7 @@ pub unsafe fn from_utf8_unchecked(v: &[u8]) -> &str {
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#[inline]
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#[stable(feature = "str_mut_extras", since = "1.20.0")]
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pub unsafe fn from_utf8_unchecked_mut(v: &mut [u8]) -> &mut str {
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mem::transmute(v)
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&*(v as *mut [u8] as *mut str)
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}
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#[stable(feature = "rust1", since = "1.0.0")]
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@ -2447,12 +2447,12 @@ impl StrExt for str {
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#[inline]
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fn as_bytes(&self) -> &[u8] {
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unsafe { mem::transmute(self) }
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unsafe { &*(self as *const str as *const [u8]) }
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}
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#[inline]
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unsafe fn as_bytes_mut(&mut self) -> &mut [u8] {
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mem::transmute(self)
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&mut *(self as *mut str as *mut [u8])
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}
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fn find<'a, P: Pattern<'a>>(&'a self, pat: P) -> Option<usize> {
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