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Merge two impl<T> Vec<T> blocks.
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The show up separately in rustdoc.

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@SimonSapin
SimonSapin committed Oct 11, 2016
1 parent be34bac commit 401f1c4
Showing 1 changed file with 124 additions and 126 deletions.
250 changes: 124 additions & 126 deletions src/libcollections/vec.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -782,6 +782,130 @@ impl<T> Vec<T> {
}
}

/// Removes consecutive elements in the vector that resolve to the same key.
///
/// If the vector is sorted, this removes all duplicates.
///
/// # Examples
///
/// ```
/// #![feature(dedup_by)]
///
/// let mut vec = vec![10, 20, 21, 30, 20];
///
/// vec.dedup_by_key(|i| *i / 10);
///
/// assert_eq!(vec, [10, 20, 30, 20]);
/// ```
#[unstable(feature = "dedup_by", reason = "recently added", issue = "37087")]
#[inline]
pub fn dedup_by_key<F, K>(&mut self, mut key: F) where F: FnMut(&mut T) -> K, K: PartialEq {
self.dedup_by(|a, b| key(a) == key(b))
}

/// Removes consecutive elements in the vector that resolve to the same key.
///
/// If the vector is sorted, this removes all duplicates.
///
/// # Examples
///
/// ```
/// #![feature(dedup_by)]
/// use std::ascii::AsciiExt;
///
/// let mut vec = vec!["foo", "bar", "Bar", "baz", "bar"];
///
/// vec.dedup_by(|a, b| a.eq_ignore_ascii_case(b));
///
/// assert_eq!(vec, ["foo", "bar", "baz", "bar"]);
/// ```
#[unstable(feature = "dedup_by", reason = "recently added", issue = "37087")]
pub fn dedup_by<F>(&mut self, mut same_bucket: F) where F: FnMut(&mut T, &mut T) -> bool {
unsafe {
// Although we have a mutable reference to `self`, we cannot make
// *arbitrary* changes. The `PartialEq` comparisons could panic, so we
// must ensure that the vector is in a valid state at all time.
//
// The way that we handle this is by using swaps; we iterate
// over all the elements, swapping as we go so that at the end
// the elements we wish to keep are in the front, and those we
// wish to reject are at the back. We can then truncate the
// vector. This operation is still O(n).
//
// Example: We start in this state, where `r` represents "next
// read" and `w` represents "next_write`.
//
// r
// +---+---+---+---+---+---+
// | 0 | 1 | 1 | 2 | 3 | 3 |
// +---+---+---+---+---+---+
// w
//
// Comparing self[r] against self[w-1], this is not a duplicate, so
// we swap self[r] and self[w] (no effect as r==w) and then increment both
// r and w, leaving us with:
//
// r
// +---+---+---+---+---+---+
// | 0 | 1 | 1 | 2 | 3 | 3 |
// +---+---+---+---+---+---+
// w
//
// Comparing self[r] against self[w-1], this value is a duplicate,
// so we increment `r` but leave everything else unchanged:
//
// r
// +---+---+---+---+---+---+
// | 0 | 1 | 1 | 2 | 3 | 3 |
// +---+---+---+---+---+---+
// w
//
// Comparing self[r] against self[w-1], this is not a duplicate,
// so swap self[r] and self[w] and advance r and w:
//
// r
// +---+---+---+---+---+---+
// | 0 | 1 | 2 | 1 | 3 | 3 |
// +---+---+---+---+---+---+
// w
//
// Not a duplicate, repeat:
//
// r
// +---+---+---+---+---+---+
// | 0 | 1 | 2 | 3 | 1 | 3 |
// +---+---+---+---+---+---+
// w
//
// Duplicate, advance r. End of vec. Truncate to w.

let ln = self.len();
if ln <= 1 {
return;
}

// Avoid bounds checks by using raw pointers.
let p = self.as_mut_ptr();
let mut r: usize = 1;
let mut w: usize = 1;

while r < ln {
let p_r = p.offset(r as isize);
let p_wm1 = p.offset((w - 1) as isize);
if !same_bucket(&mut *p_r, &mut *p_wm1) {
if r != w {
let p_w = p_wm1.offset(1);
mem::swap(&mut *p_r, &mut *p_w);
}
w += 1;
}
r += 1;
}

self.truncate(w);
}
}

/// Appends an element to the back of a collection.
///
/// # Panics
Expand Down Expand Up @@ -1162,132 +1286,6 @@ impl<T: PartialEq> Vec<T> {
}
}

impl<T> Vec<T> {
/// Removes consecutive elements in the vector that resolve to the same key.
///
/// If the vector is sorted, this removes all duplicates.
///
/// # Examples
///
/// ```
/// #![feature(dedup_by)]
///
/// let mut vec = vec![10, 20, 21, 30, 20];
///
/// vec.dedup_by_key(|i| *i / 10);
///
/// assert_eq!(vec, [10, 20, 30, 20]);
/// ```
#[unstable(feature = "dedup_by", reason = "recently added", issue = "37087")]
#[inline]
pub fn dedup_by_key<F, K>(&mut self, mut key: F) where F: FnMut(&mut T) -> K, K: PartialEq {
self.dedup_by(|a, b| key(a) == key(b))
}

/// Removes consecutive elements in the vector that resolve to the same key.
///
/// If the vector is sorted, this removes all duplicates.
///
/// # Examples
///
/// ```
/// #![feature(dedup_by)]
/// use std::ascii::AsciiExt;
///
/// let mut vec = vec!["foo", "bar", "Bar", "baz", "bar"];
///
/// vec.dedup_by(|a, b| a.eq_ignore_ascii_case(b));
///
/// assert_eq!(vec, ["foo", "bar", "baz", "bar"]);
/// ```
#[unstable(feature = "dedup_by", reason = "recently added", issue = "37087")]
pub fn dedup_by<F>(&mut self, mut same_bucket: F) where F: FnMut(&mut T, &mut T) -> bool {
unsafe {
// Although we have a mutable reference to `self`, we cannot make
// *arbitrary* changes. The `PartialEq` comparisons could panic, so we
// must ensure that the vector is in a valid state at all time.
//
// The way that we handle this is by using swaps; we iterate
// over all the elements, swapping as we go so that at the end
// the elements we wish to keep are in the front, and those we
// wish to reject are at the back. We can then truncate the
// vector. This operation is still O(n).
//
// Example: We start in this state, where `r` represents "next
// read" and `w` represents "next_write`.
//
// r
// +---+---+---+---+---+---+
// | 0 | 1 | 1 | 2 | 3 | 3 |
// +---+---+---+---+---+---+
// w
//
// Comparing self[r] against self[w-1], this is not a duplicate, so
// we swap self[r] and self[w] (no effect as r==w) and then increment both
// r and w, leaving us with:
//
// r
// +---+---+---+---+---+---+
// | 0 | 1 | 1 | 2 | 3 | 3 |
// +---+---+---+---+---+---+
// w
//
// Comparing self[r] against self[w-1], this value is a duplicate,
// so we increment `r` but leave everything else unchanged:
//
// r
// +---+---+---+---+---+---+
// | 0 | 1 | 1 | 2 | 3 | 3 |
// +---+---+---+---+---+---+
// w
//
// Comparing self[r] against self[w-1], this is not a duplicate,
// so swap self[r] and self[w] and advance r and w:
//
// r
// +---+---+---+---+---+---+
// | 0 | 1 | 2 | 1 | 3 | 3 |
// +---+---+---+---+---+---+
// w
//
// Not a duplicate, repeat:
//
// r
// +---+---+---+---+---+---+
// | 0 | 1 | 2 | 3 | 1 | 3 |
// +---+---+---+---+---+---+
// w
//
// Duplicate, advance r. End of vec. Truncate to w.

let ln = self.len();
if ln <= 1 {
return;
}

// Avoid bounds checks by using raw pointers.
let p = self.as_mut_ptr();
let mut r: usize = 1;
let mut w: usize = 1;

while r < ln {
let p_r = p.offset(r as isize);
let p_wm1 = p.offset((w - 1) as isize);
if !same_bucket(&mut *p_r, &mut *p_wm1) {
if r != w {
let p_w = p_wm1.offset(1);
mem::swap(&mut *p_r, &mut *p_w);
}
w += 1;
}
r += 1;
}

self.truncate(w);
}
}
}

////////////////////////////////////////////////////////////////////////////////
// Internal methods and functions
////////////////////////////////////////////////////////////////////////////////
Expand Down

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