From 09682676ae1c484ebaefa59c4895452b0bccc58c Mon Sep 17 00:00:00 2001
From: Jorge Aparicio <jorge@japaric.io>
Date: Tue, 31 Oct 2017 14:50:26 +0100
Subject: [PATCH] don't use indexing to elide bound checks
---
src/ring_buffer/mod.rs | 4 ++--
src/ring_buffer/spsc.rs | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/src/ring_buffer/mod.rs b/src/ring_buffer/mod.rs
index 199e82e..5647f77 100644
--- a/src/ring_buffer/mod.rs
+++ b/src/ring_buffer/mod.rs
@@ -48,7 +48,7 @@ where
let buffer: &[T] = unsafe { self.buffer.as_ref() };
if self.head != self.tail {
- let item = unsafe { ptr::read(&buffer[self.head]) };
+ let item = unsafe { ptr::read(buffer.as_ptr().offset(self.head as isize)) };
self.head = (self.head + 1) % n;
Some(item)
} else {
@@ -64,7 +64,7 @@ where
if next_tail != self.head {
// NOTE(ptr::write) the memory slot that we are about to write to is uninitialized. We
// use `ptr::write` to avoid running `T`'s destructor on the uninitialized memory
- unsafe { ptr::write(&mut buffer[self.tail], item) }
+ unsafe { ptr::write(buffer.as_mut_ptr().offset(self.tail as isize), item) }
self.tail = next_tail;
Ok(())
} else {
diff --git a/src/ring_buffer/spsc.rs b/src/ring_buffer/spsc.rs
index f12f48d..dc6d0f5 100644
--- a/src/ring_buffer/spsc.rs
+++ b/src/ring_buffer/spsc.rs
@@ -43,7 +43,7 @@ where
// NOTE(volatile) the value of `tail` can change at any time in the context of the consumer
// so we inform this to the compiler using a volatile load
if rb.head != unsafe { ptr::read_volatile(&rb.tail) } {
- let item = unsafe { ptr::read(&buffer[rb.head]) };
+ let item = unsafe { ptr::read(buffer.as_ptr().offset(rb.head as isize)) };
rb.head = (rb.head + 1) % n;
Some(item)
} else {
@@ -78,7 +78,7 @@ where
if next_tail != unsafe { ptr::read_volatile(&rb.head) } {
// NOTE(ptr::write) the memory slot that we are about to write to is uninitialized. We
// use `ptr::write` to avoid running `T`'s destructor on the uninitialized memory
- unsafe { ptr::write(&mut buffer[rb.tail], item) }
+ unsafe { ptr::write(buffer.as_mut_ptr().offset(rb.tail as isize), item) }
rb.tail = next_tail;
Ok(())
} else {
--
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