Add specializations of read_to_end for Stdin, TcpStream and File,

allowing them to read into a buffer containing uninitialized data,
rather than pay the cost of zeroing.

1 files changed, 4 insertions, 0 deletions

diff --git a/src/libstd/io/stdio.rs b/src/libstd/io/stdio.rs
index 62bbb939a71..d8b7c8a282c 100644
--- a/src/libstd/io/stdio.rs
+++ b/src/libstd/io/stdio.rs
@@ -18,6 +18,7 @@ use io::lazy::Lazy;
 use io::{self, BufReader, LineWriter};
 use sync::{Arc, Mutex, MutexGuard};
 use sys::stdio;
+use sys_common::io::{read_to_end_uninitialized};
 use sys_common::remutex::{ReentrantMutex, ReentrantMutexGuard};
 use libc;
 
@@ -277,6 +278,9 @@ impl<'a> Read for StdinLock<'a> {
     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
         self.inner.read(buf)
     }
+    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+        unsafe { read_to_end_uninitialized(self, buf) }
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]