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Correct incorrect assertion in VecDeque::wrap_copy #29545

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Merged
merged 1 commit into from
Nov 3, 2015
Merged

Correct incorrect assertion in VecDeque::wrap_copy #29545

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16 changes: 9 additions & 7 deletions src/libcollections/vec_deque.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -148,9 +148,9 @@ impl<T> VecDeque<T> {
/// Copies a contiguous block of memory len long from src to dst
#[inline]
unsafe fn copy(&self, dst: usize, src: usize, len: usize) {
debug_assert!(dst + len <= self.cap(), "dst={} src={} len={} cap={}", dst, src, len,
debug_assert!(dst + len <= self.cap(), "cpy dst={} src={} len={} cap={}", dst, src, len,
self.cap());
debug_assert!(src + len <= self.cap(), "dst={} src={} len={} cap={}", dst, src, len,
debug_assert!(src + len <= self.cap(), "cpy dst={} src={} len={} cap={}", dst, src, len,
self.cap());
ptr::copy(
self.ptr().offset(src as isize),
Expand All @@ -161,9 +161,9 @@ impl<T> VecDeque<T> {
/// Copies a contiguous block of memory len long from src to dst
#[inline]
unsafe fn copy_nonoverlapping(&self, dst: usize, src: usize, len: usize) {
debug_assert!(dst + len <= self.cap(), "dst={} src={} len={} cap={}", dst, src, len,
debug_assert!(dst + len <= self.cap(), "cno dst={} src={} len={} cap={}", dst, src, len,
self.cap());
debug_assert!(src + len <= self.cap(), "dst={} src={} len={} cap={}", dst, src, len,
debug_assert!(src + len <= self.cap(), "cno dst={} src={} len={} cap={}", dst, src, len,
self.cap());
ptr::copy_nonoverlapping(
self.ptr().offset(src as isize),
Expand All @@ -175,9 +175,11 @@ impl<T> VecDeque<T> {
/// (abs(dst - src) + len) must be no larger than cap() (There must be at
/// most one continuous overlapping region between src and dest).
unsafe fn wrap_copy(&self, dst: usize, src: usize, len: usize) {
debug_assert!(
(if src <= dst { dst - src } else { src - dst }) + len <= self.cap(),
"dst={} src={} len={} cap={}", dst, src, len, self.cap());
#[allow(dead_code)]
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I'm not sure if this is necessary come to think of it...

fn diff(a: usize, b: usize) -> usize {if a <= b {b - a} else {a - b}}
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not sure its worth very much making this function instead of keeping it inlined.

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I agree. Not a big fan of this code, but it works, which is better than the old code :)

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It's called twice, so I think it's ok.

debug_assert!(cmp::min(diff(dst, src),
self.cap() - diff(dst, src)) + len <= self.cap(),
"wrc dst={} src={} len={} cap={}", dst, src, len, self.cap());

if src == dst || len == 0 { return }

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