auto merge of #11265 : c-a/rust/byteswap_from, r=alexcrichton

This patchset adds intrinsics similar to the to_[be|le][16|32|64] intrinsics but for going in the reverse direction, e.g. from big/little endian to host endian. Implementation wise they do exactly the same as the corresponding to_* functions but I think it anyway make sense to have them since using the to_* functions in the reverse direction is not entirely intuitive.

The first patch adds the intrinsics and the two following changes instances of bswap* to use the [to|from]_* intrinsics instead.

1 files changed, 2 insertions, 6 deletions

diff --git a/src/libnative/io/net.rs b/src/libnative/io/net.rs
index 6736641c858..241a69ad4e6 100644
--- a/src/libnative/io/net.rs
+++ b/src/libnative/io/net.rs
@@ -26,15 +26,11 @@ use super::file::keep_going;
 #[cfg(windows)] pub type sock_t = libc::SOCKET;
 #[cfg(unix)]    pub type sock_t = super::file::fd_t;
 
-#[cfg(target_endian = "big")] pub fn htons(x: u16) -> u16 { x }
-#[cfg(target_endian = "big")] pub fn ntohs(x: u16) -> u16 { x }
-#[cfg(target_endian = "little")]
 pub fn htons(u: u16) -> u16 {
-    unsafe { intrinsics::bswap16(u as i16) as u16 }
+    intrinsics::to_be16(u as i16) as u16
 }
-#[cfg(target_endian = "little")]
 pub fn ntohs(u: u16) -> u16 {
-    unsafe { intrinsics::bswap16(u as i16) as u16 }
+    intrinsics::from_be16(u as i16) as u16
 }
 
 enum InAddr {