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Add overflow checking for str::get with inclusive ranges #42428

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Merged
merged 2 commits into from
Jun 14, 2017
Merged

Add overflow checking for str::get with inclusive ranges #42428

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18612b2
Delegate str:Index(Mut) to SliceIndex<str>
scottmcm Jun 4, 2017
808a08a
Add overflow checking for str::get with inclusive ranges
scottmcm Jun 4, 2017
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1 change: 1 addition & 0 deletions src/libcollections/tests/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,7 @@
#![feature(rand)]
#![feature(slice_rotate)]
#![feature(splice)]
#![feature(str_checked_slicing)]
#![feature(str_escape)]
#![feature(test)]
#![feature(unboxed_closures)]
Expand Down
42 changes: 42 additions & 0 deletions src/libcollections/tests/str.rs
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Expand Up @@ -358,6 +358,48 @@ fn test_slice_fail() {
&"中华Việt Nam"[0..2];
}

#[test]
#[should_panic]
fn test_str_slice_rangetoinclusive_max_panics() {
&"hello"[...usize::max_value()];
}

#[test]
#[should_panic]
fn test_str_slice_rangeinclusive_max_panics() {
&"hello"[1...usize::max_value()];
}

#[test]
#[should_panic]
fn test_str_slicemut_rangetoinclusive_max_panics() {
let mut s = "hello".to_owned();
let s: &mut str = &mut s;
&mut s[...usize::max_value()];
}

#[test]
#[should_panic]
fn test_str_slicemut_rangeinclusive_max_panics() {
let mut s = "hello".to_owned();
let s: &mut str = &mut s;
&mut s[1...usize::max_value()];
}

#[test]
fn test_str_get_maxinclusive() {
let mut s = "hello".to_owned();
{
let s: &str = &s;
assert_eq!(s.get(...usize::max_value()), None);
assert_eq!(s.get(1...usize::max_value()), None);
}
{
let s: &mut str = &mut s;
assert_eq!(s.get(...usize::max_value()), None);
assert_eq!(s.get(1...usize::max_value()), None);
}
}

#[test]
fn test_is_char_boundary() {
Expand Down
71 changes: 30 additions & 41 deletions src/libcore/str/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1617,12 +1617,7 @@ mod traits {

#[inline]
fn index(&self, index: ops::RangeTo<usize>) -> &str {
// is_char_boundary checks that the index is in [0, .len()]
if self.is_char_boundary(index.end) {
unsafe { self.slice_unchecked(0, index.end) }
} else {
super::slice_error_fail(self, 0, index.end)
}
index.index(self)
}
}

Expand All @@ -1636,12 +1631,7 @@ mod traits {
impl ops::IndexMut<ops::RangeTo<usize>> for str {
#[inline]
fn index_mut(&mut self, index: ops::RangeTo<usize>) -> &mut str {
// is_char_boundary checks that the index is in [0, .len()]
if self.is_char_boundary(index.end) {
unsafe { self.slice_mut_unchecked(0, index.end) }
} else {
super::slice_error_fail(self, 0, index.end)
}
index.index_mut(self)
}
}

Expand All @@ -1657,12 +1647,7 @@ mod traits {

#[inline]
fn index(&self, index: ops::RangeFrom<usize>) -> &str {
// is_char_boundary checks that the index is in [0, .len()]
if self.is_char_boundary(index.start) {
unsafe { self.slice_unchecked(index.start, self.len()) }
} else {
super::slice_error_fail(self, index.start, self.len())
}
index.index(self)
}
}

Expand All @@ -1676,13 +1661,7 @@ mod traits {
impl ops::IndexMut<ops::RangeFrom<usize>> for str {
#[inline]
fn index_mut(&mut self, index: ops::RangeFrom<usize>) -> &mut str {
// is_char_boundary checks that the index is in [0, .len()]
if self.is_char_boundary(index.start) {
let len = self.len();
unsafe { self.slice_mut_unchecked(index.start, len) }
} else {
super::slice_error_fail(self, index.start, self.len())
}
index.index_mut(self)
}
}

Expand Down Expand Up @@ -1724,9 +1703,7 @@ mod traits {

#[inline]
fn index(&self, index: ops::RangeInclusive<usize>) -> &str {
assert!(index.end != usize::max_value(),
"attempted to index str up to maximum usize");
self.index(index.start .. index.end+1)
index.index(self)
}
}

Expand All @@ -1738,9 +1715,7 @@ mod traits {

#[inline]
fn index(&self, index: ops::RangeToInclusive<usize>) -> &str {
assert!(index.end != usize::max_value(),
"attempted to index str up to maximum usize");
self.index(.. index.end+1)
index.index(self)
}
}

Expand All @@ -1750,9 +1725,7 @@ mod traits {
impl ops::IndexMut<ops::RangeInclusive<usize>> for str {
#[inline]
fn index_mut(&mut self, index: ops::RangeInclusive<usize>) -> &mut str {
assert!(index.end != usize::max_value(),
"attempted to index str up to maximum usize");
self.index_mut(index.start .. index.end+1)
index.index_mut(self)
}
}
#[unstable(feature = "inclusive_range",
Expand All @@ -1761,9 +1734,7 @@ mod traits {
impl ops::IndexMut<ops::RangeToInclusive<usize>> for str {
#[inline]
fn index_mut(&mut self, index: ops::RangeToInclusive<usize>) -> &mut str {
assert!(index.end != usize::max_value(),
"attempted to index str up to maximum usize");
self.index_mut(.. index.end+1)
index.index_mut(self)
}
}

Expand Down Expand Up @@ -1886,6 +1857,7 @@ mod traits {
}
#[inline]
fn index_mut(self, slice: &mut str) -> &mut Self::Output {
// is_char_boundary checks that the index is in [0, .len()]
if slice.is_char_boundary(self.end) {
unsafe { self.get_unchecked_mut(slice) }
} else {
Expand Down Expand Up @@ -1932,6 +1904,7 @@ mod traits {
}
#[inline]
fn index_mut(self, slice: &mut str) -> &mut Self::Output {
// is_char_boundary checks that the index is in [0, .len()]
if slice.is_char_boundary(self.start) {
unsafe { self.get_unchecked_mut(slice) }
} else {
Expand All @@ -1945,11 +1918,19 @@ mod traits {
type Output = str;
#[inline]
fn get(self, slice: &str) -> Option<&Self::Output> {
(self.start..self.end+1).get(slice)
if let Some(end) = self.end.checked_add(1) {
(self.start..end).get(slice)
} else {
None
}
}
#[inline]
fn get_mut(self, slice: &mut str) -> Option<&mut Self::Output> {
(self.start..self.end+1).get_mut(slice)
if let Some(end) = self.end.checked_add(1) {
(self.start..end).get_mut(slice)
} else {
None
}
}
#[inline]
unsafe fn get_unchecked(self, slice: &str) -> &Self::Output {
Expand All @@ -1961,10 +1942,14 @@ mod traits {
}
#[inline]
fn index(self, slice: &str) -> &Self::Output {
assert!(self.end != usize::max_value(),
"attempted to index str up to maximum usize");
(self.start..self.end+1).index(slice)
}
#[inline]
fn index_mut(self, slice: &mut str) -> &mut Self::Output {
assert!(self.end != usize::max_value(),
"attempted to index str up to maximum usize");
(self.start..self.end+1).index_mut(slice)
}
}
Expand All @@ -1976,15 +1961,15 @@ mod traits {
type Output = str;
#[inline]
fn get(self, slice: &str) -> Option<&Self::Output> {
if slice.is_char_boundary(self.end + 1) {
if self.end < usize::max_value() && slice.is_char_boundary(self.end + 1) {
Some(unsafe { self.get_unchecked(slice) })
} else {
None
}
}
#[inline]
fn get_mut(self, slice: &mut str) -> Option<&mut Self::Output> {
if slice.is_char_boundary(self.end + 1) {
if self.end < usize::max_value() && slice.is_char_boundary(self.end + 1) {
Some(unsafe { self.get_unchecked_mut(slice) })
} else {
None
Expand All @@ -2002,11 +1987,15 @@ mod traits {
}
#[inline]
fn index(self, slice: &str) -> &Self::Output {
assert!(self.end != usize::max_value(),
"attempted to index str up to maximum usize");
let end = self.end + 1;
self.get(slice).unwrap_or_else(|| super::slice_error_fail(slice, 0, end))
}
#[inline]
fn index_mut(self, slice: &mut str) -> &mut Self::Output {
assert!(self.end != usize::max_value(),
"attempted to index str up to maximum usize");
if slice.is_char_boundary(self.end) {
unsafe { self.get_unchecked_mut(slice) }
} else {
Expand Down