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authorbors <bors@rust-lang.org>2019-05-20 21:38:19 +0000
committerbors <bors@rust-lang.org>2019-05-20 21:38:19 +0000
commit09189591c4c4f6784ffd4bbe99eaefbfe1d5e4a4 (patch)
treee2b332a585664a9225c26a37f9848501c9a7e8c5 /src/liballoc
parentd35181ad8785fa958e43580a29a982afe02c728f (diff)
parent0c97800f93e13b5339773158502257b556db8392 (diff)
downloadrust-09189591c4c4f6784ffd4bbe99eaefbfe1d5e4a4.tar.gz
rust-09189591c4c4f6784ffd4bbe99eaefbfe1d5e4a4.zip
Auto merge of #60986 - Centril:rollup-nhpgrfb, r=Centril
Rollup of 11 pull requests

Successful merges:

 - #60383 (Fix position source code files toggle)
 - #60453 (Fall back to `/dev/urandom` on `EPERM` for `getrandom`)
 - #60487 (Fix search sidebar width when no crate select is present)
 - #60511 (Fix intra-doc link resolution failure on re-exporting libstd)
 - #60823 (Fix incremental compilation of cdylib emitting spurious unused_attributes lint)
 - #60915 (stable hashing: Remove unused field and add documentation.)
 - #60942 (Misc changes to rustc_metadata)
 - #60952 (Document BinaryHeap time complexity)
 - #60959 (rustc: Improve type size assertions)
 - #60972 (remove confusing remarks about mixed volatile and non-volatile accesses)
 - #60983 (Set -funwind-tables and -fno-exceptions unconditionally for LLVM's libunwind)

Failed merges:

r? @ghost
Diffstat (limited to 'src/liballoc')
-rw-r--r--src/liballoc/alloc.rs18
-rw-r--r--src/liballoc/collections/binary_heap.rs43
2 files changed, 61 insertions, 0 deletions
diff --git a/src/liballoc/alloc.rs b/src/liballoc/alloc.rs
index ddc6481eec7..41ff06d70ff 100644
--- a/src/liballoc/alloc.rs
+++ b/src/liballoc/alloc.rs
@@ -37,6 +37,8 @@ extern "Rust" {
 ///
 /// Note: while this type is unstable, the functionality it provides can be
 /// accessed through the [free functions in `alloc`](index.html#functions).
+///
+/// [`Alloc`]: trait.Alloc.html
 #[unstable(feature = "allocator_api", issue = "32838")]
 #[derive(Copy, Clone, Default, Debug)]
 pub struct Global;
@@ -54,6 +56,10 @@ pub struct Global;
 ///
 /// See [`GlobalAlloc::alloc`].
 ///
+/// [`Global`]: struct.Global.html
+/// [`Alloc`]: trait.Alloc.html
+/// [`GlobalAlloc::alloc`]: trait.GlobalAlloc.html#tymethod.alloc
+///
 /// # Examples
 ///
 /// ```
@@ -87,6 +93,10 @@ pub unsafe fn alloc(layout: Layout) -> *mut u8 {
 /// # Safety
 ///
 /// See [`GlobalAlloc::dealloc`].
+///
+/// [`Global`]: struct.Global.html
+/// [`Alloc`]: trait.Alloc.html
+/// [`GlobalAlloc::dealloc`]: trait.GlobalAlloc.html#tymethod.dealloc
 #[stable(feature = "global_alloc", since = "1.28.0")]
 #[inline]
 pub unsafe fn dealloc(ptr: *mut u8, layout: Layout) {
@@ -105,6 +115,10 @@ pub unsafe fn dealloc(ptr: *mut u8, layout: Layout) {
 /// # Safety
 ///
 /// See [`GlobalAlloc::realloc`].
+///
+/// [`Global`]: struct.Global.html
+/// [`Alloc`]: trait.Alloc.html
+/// [`GlobalAlloc::realloc`]: trait.GlobalAlloc.html#method.realloc
 #[stable(feature = "global_alloc", since = "1.28.0")]
 #[inline]
 pub unsafe fn realloc(ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 {
@@ -124,6 +138,10 @@ pub unsafe fn realloc(ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8
 ///
 /// See [`GlobalAlloc::alloc_zeroed`].
 ///
+/// [`Global`]: struct.Global.html
+/// [`Alloc`]: trait.Alloc.html
+/// [`GlobalAlloc::alloc_zeroed`]: trait.GlobalAlloc.html#method.alloc_zeroed
+///
 /// # Examples
 ///
 /// ```
diff --git a/src/liballoc/collections/binary_heap.rs b/src/liballoc/collections/binary_heap.rs
index 39fcfaa7893..c5a0b6e877b 100644
--- a/src/liballoc/collections/binary_heap.rs
+++ b/src/liballoc/collections/binary_heap.rs
@@ -231,6 +231,20 @@ use super::SpecExtend;
 /// assert_eq!(heap.pop(), Some(Reverse(5)));
 /// assert_eq!(heap.pop(), None);
 /// ```
+///
+/// # Time complexity
+///
+/// | [push] | [pop]    | [peek]/[peek\_mut] |
+/// |--------|----------|--------------------|
+/// | O(1)~  | O(log n) | O(1)               |
+///
+/// The value for `push` is an expected cost; the method documentation gives a
+/// more detailed analysis.
+///
+/// [push]: #method.push
+/// [pop]: #method.pop
+/// [peek]: #method.peek
+/// [peek\_mut]: #method.peek_mut
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct BinaryHeap<T> {
     data: Vec<T>,
@@ -384,6 +398,10 @@ impl<T: Ord> BinaryHeap<T> {
     /// }
     /// assert_eq!(heap.peek(), Some(&2));
     /// ```
+    ///
+    /// # Time complexity
+    ///
+    /// Cost is O(1) in the worst case.
     #[stable(feature = "binary_heap_peek_mut", since = "1.12.0")]
     pub fn peek_mut(&mut self) -> Option<PeekMut<'_, T>> {
         if self.is_empty() {
@@ -411,6 +429,11 @@ impl<T: Ord> BinaryHeap<T> {
     /// assert_eq!(heap.pop(), Some(1));
     /// assert_eq!(heap.pop(), None);
     /// ```
+    ///
+    /// # Time complexity
+    ///
+    /// The worst case cost of `pop` on a heap containing *n* elements is O(log
+    /// n).
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn pop(&mut self) -> Option<T> {
         self.data.pop().map(|mut item| {
@@ -438,6 +461,22 @@ impl<T: Ord> BinaryHeap<T> {
     /// assert_eq!(heap.len(), 3);
     /// assert_eq!(heap.peek(), Some(&5));
     /// ```
+    ///
+    /// # Time complexity
+    ///
+    /// The expected cost of `push`, averaged over every possible ordering of
+    /// the elements being pushed, and over a sufficiently large number of
+    /// pushes, is O(1). This is the most meaningful cost metric when pushing
+    /// elements that are *not* already in any sorted pattern.
+    ///
+    /// The time complexity degrades if elements are pushed in predominantly
+    /// ascending order. In the worst case, elements are pushed in ascending
+    /// sorted order and the amortized cost per push is O(log n) against a heap
+    /// containing *n* elements.
+    ///
+    /// The worst case cost of a *single* call to `push` is O(n). The worst case
+    /// occurs when capacity is exhausted and needs a resize. The resize cost
+    /// has been amortized in the previous figures.
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn push(&mut self, item: T) {
         let old_len = self.len();
@@ -650,6 +689,10 @@ impl<T> BinaryHeap<T> {
     /// assert_eq!(heap.peek(), Some(&5));
     ///
     /// ```
+    ///
+    /// # Time complexity
+    ///
+    /// Cost is O(1) in the worst case.
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn peek(&self) -> Option<&T> {
         self.data.get(0)