Have quicksort take a compare function rather than requires Ord and Eq.

This commit is contained in:
Simon Sapin 2014-08-12 14:48:39 +01:00
parent 1cbe73c583
commit 9ce519ba21
2 changed files with 18 additions and 40 deletions

View file

@ -125,7 +125,11 @@ impl SelectorMap {
shareable);
// Sort only the rules we just added.
sort::quicksort(matching_rules_list.vec_mut_slice_from(init_len));
sort::quicksort_by(matching_rules_list.vec_mut_slice_from(init_len), compare);
fn compare(a: &DeclarationBlock, b: &DeclarationBlock) -> Ordering {
(a.specificity, a.source_order).cmp(&(b.specificity, b.source_order))
}
}
fn get_matching_rules_from_hash<E:TElement,
@ -469,34 +473,6 @@ impl DeclarationBlock {
}
}
impl PartialEq for DeclarationBlock {
#[inline]
fn eq(&self, other: &DeclarationBlock) -> bool {
let this_rank = (self.specificity, self.source_order);
let other_rank = (other.specificity, other.source_order);
this_rank == other_rank
}
}
impl Eq for DeclarationBlock {}
impl PartialOrd for DeclarationBlock {
#[inline]
fn partial_cmp(&self, other: &DeclarationBlock) -> Option<Ordering> {
let this_rank = (self.specificity, self.source_order);
let other_rank = (other.specificity, other.source_order);
this_rank.partial_cmp(&other_rank)
}
}
impl Ord for DeclarationBlock {
#[inline]
fn cmp(&self, other: &DeclarationBlock) -> Ordering {
let this_rank = (self.specificity, self.source_order);
let other_rank = (other.specificity, other.source_order);
this_rank.cmp(&other_rank)
}
}
/// Determines whether the given element matches the given single or compound selector.
///
@ -968,7 +944,8 @@ mod tests {
let rules_list = get_mock_rules(["a.intro", "img.sidebar"]);
let a = &rules_list[0][0].declarations;
let b = &rules_list[1][0].declarations;
assert!(a < b, "The rule that comes later should win.");
assert!((a.specificity, a.source_order).cmp(&(b.specificity, b.source_order)) == Less,
"The rule that comes later should win.");
}
#[test]

View file

@ -4,7 +4,7 @@
//! In-place sorting.
fn quicksort_helper<T:Ord + Eq + PartialOrd + PartialEq>(arr: &mut [T], left: int, right: int) {
fn quicksort_helper<T>(arr: &mut [T], left: int, right: int, compare: fn(&T, &T) -> Ordering) {
if right <= left {
return
}
@ -17,11 +17,11 @@ fn quicksort_helper<T:Ord + Eq + PartialOrd + PartialEq>(arr: &mut [T], left: in
let v: *mut T = &mut arr[right as uint];
loop {
i += 1;
while arr[i as uint] < (*v) {
while compare(&arr[i as uint], &*v) == Less {
i += 1
}
j -= 1;
while (*v) < arr[j as uint] {
while compare(&*v, &arr[j as uint]) == Less {
if j == left {
break
}
@ -31,11 +31,11 @@ fn quicksort_helper<T:Ord + Eq + PartialOrd + PartialEq>(arr: &mut [T], left: in
break
}
arr.swap(i as uint, j as uint);
if arr[i as uint] == (*v) {
if compare(&arr[i as uint], &*v) == Equal {
p += 1;
arr.swap(p as uint, i as uint)
}
if (*v) == arr[j as uint] {
if compare(&*v, &arr[j as uint]) == Equal {
q -= 1;
arr.swap(j as uint, q as uint)
}
@ -60,21 +60,21 @@ fn quicksort_helper<T:Ord + Eq + PartialOrd + PartialEq>(arr: &mut [T], left: in
assert!(k != 0);
}
quicksort_helper(arr, left, j);
quicksort_helper(arr, i, right);
quicksort_helper(arr, left, j, compare);
quicksort_helper(arr, i, right, compare);
}
/// An in-place quicksort.
///
/// The algorithm is from Sedgewick and Bentley, "Quicksort is Optimal":
/// http://www.cs.princeton.edu/~rs/talks/QuicksortIsOptimal.pdf
pub fn quicksort<T:Ord + Eq + PartialOrd + PartialEq>(arr: &mut [T]) {
pub fn quicksort_by<T>(arr: &mut [T], compare: fn(&T, &T) -> Ordering) {
if arr.len() <= 1 {
return
}
let len = arr.len();
quicksort_helper(arr, 0, (len - 1) as int);
quicksort_helper(arr, 0, (len - 1) as int, compare);
}
#[cfg(test)]
@ -90,7 +90,8 @@ pub mod test {
for _ in range(0u32, 50000u32) {
let len: uint = rng.gen();
let mut v: Vec<int> = rng.gen_iter::<int>().take((len % 32) + 1).collect();
sort::quicksort(v.as_mut_slice());
fn compare_ints(a: &int, b: &int) -> Ordering { a.cmp(b) }
sort::quicksort_by(v.as_mut_slice(), compare_ints);
for i in range(0, v.len() - 1) {
assert!(v.get(i) <= v.get(i + 1))
}