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revert PriorityQueue to using init() #6461

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revert PriorityQueue to using init() #6461

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60 changes: 4 additions & 56 deletions src/libstd/priority_queue.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -12,14 +12,7 @@

use core::old_iter::BaseIter;
use core::util::{replace, swap};

#[abi = "rust-intrinsic"]
extern "rust-intrinsic" {
fn move_val_init<T>(dst: &mut T, src: T);
fn init<T>() -> T;
#[cfg(not(stage0))]
fn uninit<T>() -> T;
}
use core::unstable::intrinsics::{init, move_val_init};

pub struct PriorityQueue<T> {
priv data: ~[T],
Expand Down Expand Up @@ -141,33 +134,13 @@ pub impl <T:Ord> PriorityQueue<T> {

// The implementations of siftup and siftdown use unsafe blocks in
// order to move an element out of the vector (leaving behind a
// junk element), shift along the others and move it back into the
// zeroed element), shift along the others and move it back into the
// vector over the junk element. This reduces the constant factor
// compared to using swaps, which involves twice as many moves.

#[cfg(not(stage0))]
priv fn siftup(&mut self, start: uint, mut pos: uint) {
unsafe {
let new = *ptr::to_unsafe_ptr(&self.data[pos]);

while pos > start {
let parent = (pos - 1) >> 1;
if new > self.data[parent] {
let x = replace(&mut self.data[parent], uninit());
move_val_init(&mut self.data[pos], x);
pos = parent;
loop
}
break
}
move_val_init(&mut self.data[pos], new);
}
}

#[cfg(stage0)]
priv fn siftup(&mut self, start: uint, mut pos: uint) {
unsafe {
let new = *ptr::to_unsafe_ptr(&self.data[pos]);
let new = replace(&mut self.data[pos], init());

while pos > start {
let parent = (pos - 1) >> 1;
Expand All @@ -183,35 +156,10 @@ pub impl <T:Ord> PriorityQueue<T> {
}
}


#[cfg(not(stage0))]
priv fn siftdown_range(&mut self, mut pos: uint, end: uint) {
unsafe {
let start = pos;
let new = *ptr::to_unsafe_ptr(&self.data[pos]);

let mut child = 2 * pos + 1;
while child < end {
let right = child + 1;
if right < end && !(self.data[child] > self.data[right]) {
child = right;
}
let x = replace(&mut self.data[child], uninit());
move_val_init(&mut self.data[pos], x);
pos = child;
child = 2 * pos + 1;
}

move_val_init(&mut self.data[pos], new);
self.siftup(start, pos);
}
}

#[cfg(stage0)]
priv fn siftdown_range(&mut self, mut pos: uint, end: uint) {
unsafe {
let start = pos;
let new = *ptr::to_unsafe_ptr(&self.data[pos]);
let new = replace(&mut self.data[pos], init());

let mut child = 2 * pos + 1;
while child < end {
Expand Down