OpenE2K
/
rust
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Initialize memory for BufferedReader buffer 

It's passed to the underlying reader, so uninitialized memory == sad
times.

We might want to shrink the default buffer size as well. 64k is pretty
huge. Java uses 8k by default, and Go uses 4k for reference.
This commit is contained in:
Steven Fackler 2015-01-12 19:50:33 -08:00
parent 3d5fbae338
commit 89f1848b55
1 changed files with 10 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
src/libstd/io/buffered.rs
View File

@ -15,7 +15,7 @@
use cmp;
use fmt;
use io::{Reader, Writer, Stream, Buffer, DEFAULT_BUF_SIZE, IoResult};
use iter::{IteratorExt, ExactSizeIterator};
use iter::{IteratorExt, ExactSizeIterator, repeat};
use ops::Drop;
use option::Option;
use option::Option::{Some, None};
@ -62,17 +62,11 @@ impl<R> fmt::Show for BufferedReader<R> where R: fmt::Show {
impl<R: Reader> BufferedReader<R> {
/// Creates a new `BufferedReader` with the specified buffer capacity
pub fn with_capacity(cap: uint, inner: R) -> BufferedReader<R> {
// It's *much* faster to create an uninitialized buffer than it is to
// fill everything in with 0. This buffer is entirely an implementation
// detail and is never exposed, so we're safe to not initialize
// everything up-front. This allows creation of BufferedReader instances
// to be very cheap (large mallocs are not nearly as expensive as large
// callocs).
let mut buf = Vec::with_capacity(cap);
unsafe { buf.set_len(cap); }
BufferedReader {
inner: inner,
buf: buf,
// We can't use the same trick here as we do for BufferedWriter,
// since this memory is visible to the inner Reader.
buf: repeat(0).take(cap).collect(),
pos: 0,
cap: 0,
}
@ -166,7 +160,12 @@ impl<W> fmt::Show for BufferedWriter<W> where W: fmt::Show {
impl<W: Writer> BufferedWriter<W> {
/// Creates a new `BufferedWriter` with the specified buffer capacity
pub fn with_capacity(cap: uint, inner: W) -> BufferedWriter<W> {
// See comments in BufferedReader for why this uses unsafe code.
// It's *much* faster to create an uninitialized buffer than it is to
// fill everything in with 0. This buffer is entirely an implementation
// detail and is never exposed, so we're safe to not initialize
// everything up-front. This allows creation of BufferedWriter instances
// to be very cheap (large mallocs are not nearly as expensive as large
// callocs).
let mut buf = Vec::with_capacity(cap);
unsafe { buf.set_len(cap); }
BufferedWriter {