From b46d3fd32ebdf2059cd29b98aaecd0c79ccbaa2b Mon Sep 17 00:00:00 2001
From: Carl Lerche <me@carllerche.com>
Date: Mon, 20 Feb 2017 21:07:25 -0800
Subject: [PATCH] Tweak growth algorithm in BytesMut::reserve
---
src/bytes.rs | 4 ++--
tests/test_bytes.rs | 14 ++++++++++++--
2 files changed, 14 insertions(+), 4 deletions(-)
diff --git a/src/bytes.rs b/src/bytes.rs
index f65f772..d830b97 100644
--- a/src/bytes.rs
+++ b/src/bytes.rs
@@ -1695,12 +1695,12 @@ impl Inner {
// asking for more than the initial buffer capacity. Allocate more
// than requested if `new_cap` is not much bigger than the current
// capacity.
- new_cap = cmp::max(len << 1, new_cap);
+ new_cap = cmp::max(v.capacity() << 1, new_cap);
}
}
// Create a new vector to store the data
- let mut v = Vec::with_capacity(new_cap);
+ let mut v = Vec::with_capacity(new_cap.next_power_of_two());
// Copy the bytes
v.extend_from_slice(self.as_ref());
diff --git a/tests/test_bytes.rs b/tests/test_bytes.rs
index 89bddaf..2343fea 100644
--- a/tests/test_bytes.rs
+++ b/tests/test_bytes.rs
@@ -207,7 +207,7 @@ fn fns_defined_for_bytes_mut() {
}
#[test]
-fn reserve() {
+fn reserve_convert() {
// Inline -> Vec
let mut bytes = BytesMut::with_capacity(8);
bytes.put("hello");
@@ -236,11 +236,21 @@ fn reserve() {
let a = bytes.drain_to(30);
bytes.reserve(128);
- assert_eq!(bytes.capacity(), bytes.len() + 128);
+ assert_eq!(bytes.capacity(), (bytes.len() + 128).next_power_of_two());
drop(a);
}
+#[test]
+fn reserve_growth() {
+ let mut bytes = BytesMut::with_capacity(64);
+ bytes.put("hello world");
+ let _ = bytes.drain();
+
+ bytes.reserve(65);
+ assert_eq!(bytes.capacity(), 128);
+}
+
#[test]
fn inline_storage() {
let mut bytes = BytesMut::with_capacity(inline_cap());
--
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