From d315d00a3b39d655cf6aaa916d4dabe7763326ce Mon Sep 17 00:00:00 2001
From: Stepan Koltsov <stepan.koltsov@gmail.com>
Date: Sat, 1 Jul 2017 06:33:35 +0300
Subject: [PATCH] Bytes::with_capacity (#137)
---
src/bytes.rs | 48 +++++++++++++++++++++++++++++++++---------------
1 file changed, 33 insertions(+), 15 deletions(-)
diff --git a/src/bytes.rs b/src/bytes.rs
index b53fbff..034bf69 100644
--- a/src/bytes.rs
+++ b/src/bytes.rs
@@ -370,6 +370,38 @@ const INLINE_CAP: usize = 4 * 4 - 1;
*/
impl Bytes {
+ /// Create a new `Bytes` with the specified capacity.
+ ///
+ /// The returned `Bytes` will be able to hold at least `capacity` bytes
+ /// without reallocating. If `capacity` is under `3 * size:of::<usize>()`,
+ /// then `BytesMut` will not allocate.
+ ///
+ /// It is important to note that this function does not specify the length
+ /// of the returned `Bytes`, but only the capacity.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use bytes::Bytes;
+ ///
+ /// let mut bytes = Bytes::with_capacity(64);
+ ///
+ /// // `bytes` contains no data, even though there is capacity
+ /// assert_eq!(bytes.len(), 0);
+ ///
+ /// bytes.extend_from_slice(&b"hello world"[..]);
+ ///
+ /// assert_eq!(&bytes[..], b"hello world");
+ /// ```
+ #[inline]
+ pub fn with_capacity(capacity: usize) -> Bytes {
+ Bytes {
+ inner: Inner2 {
+ inner: Inner::with_capacity(capacity),
+ },
+ }
+ }
+
/// Creates a new empty `Bytes`
///
/// This will not allocate and the returned `Bytes` handle will be empty.
@@ -384,11 +416,7 @@ impl Bytes {
/// ```
#[inline]
pub fn new() -> Bytes {
- Bytes {
- inner: Inner2 {
- inner: Inner::empty(),
- }
- }
+ Bytes::with_capacity(0)
}
/// Creates a new `Bytes` from a static slice.
@@ -1553,16 +1581,6 @@ impl<'a> Extend<&'a u8> for BytesMut {
*/
impl Inner {
- #[inline]
- fn empty() -> Inner {
- Inner {
- arc: AtomicPtr::new(KIND_VEC as *mut Shared),
- ptr: ptr::null_mut(),
- len: 0,
- cap: 0,
- }
- }
-
#[inline]
fn from_static(bytes: &'static [u8]) -> Inner {
let ptr = bytes.as_ptr() as *mut u8;
--
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