From 7e8373da8d7e4553bbf9793c664fc200f2f61046 Mon Sep 17 00:00:00 2001
From: Sean McArthur <sean.monstar@gmail.com>
Date: Thu, 15 Jun 2017 10:55:02 -0700
Subject: [PATCH] Faster From<[u8]> for BytesMut, remove panic in fmt::Write
(#133)
* use slice.to_vec instead of buf.put in From<[u8]>
* don't panic in fmt::Write for BytesMut
---
benches/bytes.rs | 24 ++++++++++++++++++++++++
src/bytes.rs | 15 +++++++++------
tests/test_bytes.rs | 22 ++++++++++++++++++++++
3 files changed, 55 insertions(+), 6 deletions(-)
diff --git a/benches/bytes.rs b/benches/bytes.rs
index ff07395..86eb9c4 100644
--- a/benches/bytes.rs
+++ b/benches/bytes.rs
@@ -127,6 +127,30 @@ fn drain_write_drain(b: &mut Bencher) {
})
}
+#[bench]
+fn fmt_write(b: &mut Bencher) {
+ use std::fmt::Write;
+ let mut buf = BytesMut::with_capacity(128);
+ let s = "foo bar baz quux lorem ipsum dolor et";
+
+ b.bytes = s.len() as u64;
+ b.iter(|| {
+ let _ = write!(buf, "{}", s);
+ test::black_box(&buf);
+ unsafe { buf.set_len(0); }
+ })
+}
+
+#[bench]
+fn from_long_slice(b: &mut Bencher) {
+ let data = [0u8; 128];
+ b.bytes = data.len() as u64;
+ b.iter(|| {
+ let buf = BytesMut::from(&data[..]);
+ test::black_box(buf);
+ })
+}
+
#[bench]
fn slice_empty(b: &mut Bencher) {
b.iter(|| {
diff --git a/src/bytes.rs b/src/bytes.rs
index fd0317d..5945f3d 100644
--- a/src/bytes.rs
+++ b/src/bytes.rs
@@ -1418,10 +1418,7 @@ impl<'a> From<&'a [u8]> for BytesMut {
}
}
} else {
- let mut buf = BytesMut::with_capacity(src.len());
- let src: &[u8] = src.as_ref();
- buf.put(src);
- buf
+ BytesMut::from(src.to_vec())
}
}
}
@@ -1487,11 +1484,17 @@ impl Borrow<[u8]> for BytesMut {
}
impl fmt::Write for BytesMut {
+ #[inline]
fn write_str(&mut self, s: &str) -> fmt::Result {
- BufMut::put(self, s);
- Ok(())
+ if self.remaining_mut() >= s.len() {
+ self.put_slice(s.as_bytes());
+ Ok(())
+ } else {
+ Err(fmt::Error)
+ }
}
+ #[inline]
fn write_fmt(&mut self, args: fmt::Arguments) -> fmt::Result {
fmt::write(self, args)
}
diff --git a/tests/test_bytes.rs b/tests/test_bytes.rs
index c8d23d3..b966fe0 100644
--- a/tests/test_bytes.rs
+++ b/tests/test_bytes.rs
@@ -51,6 +51,28 @@ fn fmt() {
assert_eq!(a, b);
}
+#[test]
+fn fmt_write() {
+ use std::fmt::Write;
+ use std::iter::FromIterator;
+ let s = String::from_iter((0..10).map(|_| "abcdefg"));
+
+ let mut a = BytesMut::with_capacity(64);
+ write!(a, "{}", &s[..64]).unwrap();
+ assert_eq!(a, s[..64].as_bytes());
+
+
+ let mut b = BytesMut::with_capacity(64);
+ write!(b, "{}", &s[..32]).unwrap();
+ write!(b, "{}", &s[32..64]).unwrap();
+ assert_eq!(b, s[..64].as_bytes());
+
+
+ let mut c = BytesMut::with_capacity(64);
+ write!(c, "{}", s).unwrap_err();
+ assert!(c.is_empty());
+}
+
#[test]
fn len() {
let a = Bytes::from(&b"abcdefg"[..]);
--
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