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Replaced union with transmute

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rodrimati1992 2020-08-13 15:56:23 -03:00 committed by GitHub
parent a915bbf780
commit 1767c8bdf0
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1 changed files with 4 additions and 10 deletions
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14
library/core/src/str/mod.rs
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@ -381,12 +381,6 @@ pub fn from_utf8_mut(v: &mut [u8]) -> Result<&mut str, Utf8Error> {
Ok(unsafe { from_utf8_unchecked_mut(v) })
}
#[repr(C)]
union StrOrSlice<'a> {
str: &'a str,
slice: &'a [u8],
}
/// Converts a slice of bytes to a string slice without checking
/// that the string contains valid UTF-8.
///
@ -422,11 +416,11 @@ union StrOrSlice<'a> {
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_unstable(feature = "const_str_from_utf8_unchecked", issue = "75196")]
#[allow(unused_attributes)]
#[allow_internal_unstable(const_fn_union)]
#[allow_internal_unstable(const_fn_transmute)]
pub const unsafe fn from_utf8_unchecked(v: &[u8]) -> &str {
// SAFETY: the caller must guarantee that the bytes `v` are valid UTF-8.
// Also relies on `&str` and `&[u8]` having the same layout.
unsafe { StrOrSlice { slice: v }.str }
unsafe { mem::transmute(self) }
}
/// Converts a slice of bytes to a string slice without checking
@ -2355,10 +2349,10 @@ impl str {
#[rustc_const_stable(feature = "str_as_bytes", since = "1.32.0")]
#[inline(always)]
#[allow(unused_attributes)]
#[allow_internal_unstable(const_fn_union)]
#[allow_internal_unstable(const_fn_transmute)]
pub const fn as_bytes(&self) -> &[u8] {
// SAFETY: const sound because we transmute two types with the same layout
unsafe { StrOrSlice { str: self }.slice }
unsafe { mem::transmute(self) }
}
/// Converts a mutable string slice to a mutable byte slice.