diff options
| -rw-r--r-- | library/std/src/lib.rs | 1 | ||||
| -rw-r--r-- | library/std/src/net/ip.rs | 54 |
2 files changed, 28 insertions, 27 deletions
diff --git a/library/std/src/lib.rs b/library/std/src/lib.rs index 0569e46241a..f0487e0dff1 100644 --- a/library/std/src/lib.rs +++ b/library/std/src/lib.rs @@ -249,6 +249,7 @@ #![feature(clamp)] #![feature(concat_idents)] #![feature(const_cstr_unchecked)] +#![feature(const_fn_transmute)] #![feature(const_raw_ptr_deref)] #![feature(container_error_extra)] #![feature(core_intrinsics)] diff --git a/library/std/src/net/ip.rs b/library/std/src/net/ip.rs index 159ab981b23..5d103e64037 100644 --- a/library/std/src/net/ip.rs +++ b/library/std/src/net/ip.rs @@ -10,6 +10,7 @@ use crate::cmp::Ordering; use crate::fmt::{self, Write as FmtWrite}; use crate::hash; use crate::io::Write as IoWrite; +use crate::mem::transmute; use crate::sys::net::netc as c; use crate::sys_common::{AsInner, FromInner}; @@ -1045,27 +1046,23 @@ impl Ipv6Addr { /// ``` #[stable(feature = "rust1", since = "1.0.0")] #[rustc_const_stable(feature = "const_ipv6", since = "1.32.0")] + #[allow_internal_unstable(const_fn_transmute)] pub const fn new(a: u16, b: u16, c: u16, d: u16, e: u16, f: u16, g: u16, h: u16) -> Ipv6Addr { + let addr16 = [ + a.to_be(), + b.to_be(), + c.to_be(), + d.to_be(), + e.to_be(), + f.to_be(), + g.to_be(), + h.to_be(), + ]; Ipv6Addr { inner: c::in6_addr { - s6_addr: [ - (a >> 8) as u8, - a as u8, - (b >> 8) as u8, - b as u8, - (c >> 8) as u8, - c as u8, - (d >> 8) as u8, - d as u8, - (e >> 8) as u8, - e as u8, - (f >> 8) as u8, - f as u8, - (g >> 8) as u8, - g as u8, - (h >> 8) as u8, - h as u8, - ], + // All elements in `addr16` are big endian. + // SAFETY: `[u16; 8]` is always safe to transmute to `[u8; 16]`. + s6_addr: unsafe { transmute::<_, [u8; 16]>(addr16) }, }, } } @@ -1108,16 +1105,19 @@ impl Ipv6Addr { /// ``` #[stable(feature = "rust1", since = "1.0.0")] pub fn segments(&self) -> [u16; 8] { - let arr = &self.inner.s6_addr; + // All elements in `s6_addr` must be big endian. + // SAFETY: `[u8; 16]` is always safe to transmute to `[u16; 8]`. + let [a, b, c, d, e, f, g, h] = unsafe { transmute::<_, [u16; 8]>(self.inner.s6_addr) }; + // We want native endian u16 [ - u16::from_be_bytes([arr[0], arr[1]]), - u16::from_be_bytes([arr[2], arr[3]]), - u16::from_be_bytes([arr[4], arr[5]]), - u16::from_be_bytes([arr[6], arr[7]]), - u16::from_be_bytes([arr[8], arr[9]]), - u16::from_be_bytes([arr[10], arr[11]]), - u16::from_be_bytes([arr[12], arr[13]]), - u16::from_be_bytes([arr[14], arr[15]]), + u16::from_be(a), + u16::from_be(b), + u16::from_be(c), + u16::from_be(d), + u16::from_be(e), + u16::from_be(f), + u16::from_be(g), + u16::from_be(h), ] } |