nordic-dev.net/rust
nordic-dev.net/rust
2
0
Fork 0
mirror of https://github.com/rust-lang/rust.git synced 2024-12-01 11:13:43 +00:00
Code Issues Packages Projects Releases Wiki Activity

auto merge of #18108 : mahkoh/rust/buffered_reader, r=alexcrichton

Browse Source 
This optimizes `read` for the case in which the number of bytes
requested is larger than the internal buffer. Note that the first
comparison occurs again right afterwards and should thus be free. The
second comparison occurs only in the cold branch.
This commit is contained in:
bors 2014-10-20 03:27:12 +00:00
commit 045bc283ec
1 changed files with 11 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
src/libstd/io/buffered.rs
View File

@ -104,6 +104,9 @@ impl<R: Reader> Buffer for BufferedReader<R> {
impl<R: Reader> Reader for BufferedReader<R> { impl<R: Reader> Reader for BufferedReader<R> {
fn read(&mut self, buf: &mut [u8]) -> IoResult<uint> { fn read(&mut self, buf: &mut [u8]) -> IoResult<uint> {
if self.pos == self.cap && buf.len() >= self.buf.capacity() {
return self.inner.read(buf);
}
let nread = { let nread = {
let available = try!(self.fill_buf()); let available = try!(self.fill_buf());
let nread = cmp::min(available.len(), buf.len()); let nread = cmp::min(available.len(), buf.len());
@ -409,13 +412,19 @@ mod test {
#[test] #[test]
fn test_buffered_reader() { fn test_buffered_reader() {
let inner = MemReader::new(vec!(0, 1, 2, 3, 4)); let inner = MemReader::new(vec!(5, 6, 7, 0, 1, 2, 3, 4));
let mut reader = BufferedReader::with_capacity(2, inner); let mut reader = BufferedReader::with_capacity(2, inner);
let mut buf = [0, 0, 0]; let mut buf = [0, 0, 0];
let nread = reader.read(buf); let nread = reader.read(buf);
assert_eq!(Ok(3), nread);
let b: &[_] = &[5, 6, 7];
assert_eq!(buf.as_slice(), b);
let mut buf = [0, 0];
let nread = reader.read(buf);
assert_eq!(Ok(2), nread); assert_eq!(Ok(2), nread);
let b: &[_] = &[0, 1, 0]; let b: &[_] = &[0, 1];
assert_eq!(buf.as_slice(), b); assert_eq!(buf.as_slice(), b);
let mut buf = [0]; let mut buf = [0];