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get rid of implicit vec copies in treemap iterator

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Each call to next() was doing a copy rather than a move. There's
currently no way for this to be a method that uses &mut self, so it has
to be a free function. Closes #4763.
This commit is contained in:
Daniel Micay 2013-02-06 02:27:33 -05:00
parent 5b6c26b4e4
commit 37e998696f
1 changed files with 67 additions and 69 deletions
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136
src/libstd/treemap.rs
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@ -49,8 +49,8 @@ impl <K: Eq Ord, V: Eq> TreeMap<K, V>: Eq {
let mut y = other.iter();
for self.len().times {
unsafe { // unsafe as a purity workaround
x = x.next();
y = y.next();
map_next(&mut x);
map_next(&mut y);
// FIXME: #4492 (ICE), x.get() == y.get()
let (x1, x2) = x.get().unwrap();
let (y1, y2) = y.get().unwrap();
@ -74,8 +74,8 @@ impl <K: Eq Ord, V: Eq> TreeMap<K, V>: Eq {
let (a_len, b_len) = (a.len(), b.len());
for uint::min(a_len, b_len).times {
unsafe { // purity workaround
x = x.next();
y = y.next();
map_next(&mut x);
map_next(&mut y);
let (key_a,_) = x.get().unwrap();
let (key_b,_) = y.get().unwrap();
if *key_a < *key_b { return true; }
@ -210,32 +210,30 @@ impl <K: Ord, V> TreeMapIterator<K, V> {
// Returns the current node, or None if this iterator is at the end.
fn get(&const self) -> Option<(&self/K, &self/V)> {
match self.current {
Some(res) => Some((&res.key, &res.value)),
None => None
Some(res) => Some((&res.key, &res.value)),
None => None
}
}
}
/// Advance the iterator to the next node (in order). If this iterator
/// is finished, does nothing.
fn next(self) -> TreeMapIterator/&self<K, V> {
let mut this = self;
while !this.stack.is_empty() || this.node.is_some() {
match *this.node {
Some(ref x) => {
this.stack.push(x);
this.node = &x.left;
}
None => {
let res = this.stack.pop();
this.node = &res.right;
this.current = Some(res);
return this;
}
}
/// Advance the iterator to the next node (in order). If this iterator
/// is finished, does nothing.
fn map_next<K: Ord, V>(iter: &mut TreeMapIterator/&a<K, V>) {
while !iter.stack.is_empty() || iter.node.is_some() {
match *iter.node {
Some(ref x) => {
iter.stack.push(x);
iter.node = &x.left;
}
None => {
let res = iter.stack.pop();
iter.node = &res.right;
iter.current = Some(res);
return;
}
}
this.current = None;
return this;
}
iter.current = None;
}
pub struct TreeSet<T> {
@ -297,18 +295,18 @@ fn remove(&mut self, value: &T) -> bool { self.map.remove(value) }
let mut x = self.iter();
let mut y = other.iter();
unsafe { // purity workaround
x = x.next();
y = y.next();
set_next(&mut x);
set_next(&mut y);
let mut a = x.get();
let mut b = y.get();
while a.is_some() && b.is_some() {
let a1 = a.unwrap();
let b1 = b.unwrap();
if a1 < b1 {
x = x.next();
set_next(&mut x);
a = x.get();
} else if b1 < a1 {
y = y.next();
set_next(&mut y);
b = y.get();
} else {
return false;
@ -328,8 +326,8 @@ fn remove(&mut self, value: &T) -> bool { self.map.remove(value) }
let mut x = self.iter();
let mut y = other.iter();
unsafe { // purity workaround
x = x.next();
y = y.next();
set_next(&mut x);
set_next(&mut y);
let mut a = x.get();
let mut b = y.get();
while b.is_some() {
@ -345,10 +343,10 @@ fn remove(&mut self, value: &T) -> bool { self.map.remove(value) }
}
if !(a1 < b1) {
y = y.next();
set_next(&mut y);
b = y.get();
}
x = x.next();
set_next(&mut x);
a = x.get();
}
}
@ -361,15 +359,15 @@ fn remove(&mut self, value: &T) -> bool { self.map.remove(value) }
let mut y = other.iter();
unsafe { // purity workaround
x = x.next();
y = y.next();
set_next(&mut x);
set_next(&mut y);
let mut a = x.get();
let mut b = y.get();
while a.is_some() {
if b.is_none() {
return do a.while_some() |a1| {
if f(a1) { x = x.next(); x.get() } else { None }
if f(a1) { set_next(&mut x); x.get() } else { None }
}
}
@ -378,11 +376,11 @@ fn remove(&mut self, value: &T) -> bool { self.map.remove(value) }
if a1 < b1 {
if !f(a1) { return }
x = x.next();
set_next(&mut x);
a = x.get();
} else {
if !(b1 < a1) { x = x.next(); a = x.get() }
y = y.next();
if !(b1 < a1) { set_next(&mut x); a = x.get() }
set_next(&mut y);
b = y.get();
}
}
@ -396,15 +394,15 @@ fn remove(&mut self, value: &T) -> bool { self.map.remove(value) }
let mut y = other.iter();
unsafe { // purity workaround
x = x.next();
y = y.next();
set_next(&mut x);
set_next(&mut y);
let mut a = x.get();
let mut b = y.get();
while a.is_some() {
if b.is_none() {
return do a.while_some() |a1| {
if f(a1) { x.next(); x.get() } else { None }
if f(a1) { set_next(&mut x); x.get() } else { None }
}
}
@ -413,21 +411,21 @@ fn remove(&mut self, value: &T) -> bool { self.map.remove(value) }
if a1 < b1 {
if !f(a1) { return }
x = x.next();
set_next(&mut x);
a = x.get();
} else {
if b1 < a1 {
if !f(b1) { return }
} else {
x = x.next();
set_next(&mut x);
a = x.get();
}
y = y.next();
set_next(&mut y);
b = y.get();
}
}
do b.while_some |b1| {
if f(b1) { y = y.next(); y.get() } else { None }
if f(b1) { set_next(&mut y); y.get() } else { None }
}
}
}
@ -438,8 +436,8 @@ fn remove(&mut self, value: &T) -> bool { self.map.remove(value) }
let mut y = other.iter();
unsafe { // purity workaround
x = x.next();
y = y.next();
set_next(&mut x);
set_next(&mut y);
let mut a = x.get();
let mut b = y.get();
@ -447,13 +445,13 @@ fn remove(&mut self, value: &T) -> bool { self.map.remove(value) }
let a1 = a.unwrap();
let b1 = b.unwrap();
if a1 < b1 {
x = x.next();
set_next(&mut x);
a = x.get();
} else {
if !(b1 < a1) {
if !f(a1) { return }
}
y = y.next();
set_next(&mut y);
b = y.get();
}
}
@ -466,15 +464,15 @@ fn remove(&mut self, value: &T) -> bool { self.map.remove(value) }
let mut y = other.iter();
unsafe { // purity workaround
x = x.next();
y = y.next();
set_next(&mut x);
set_next(&mut y);
let mut a = x.get();
let mut b = y.get();
while a.is_some() {
if b.is_none() {
return do a.while_some() |a1| {
if f(a1) { x = x.next(); x.get() } else { None }
if f(a1) { set_next(&mut x); x.get() } else { None }
}
}
@ -483,15 +481,15 @@ fn remove(&mut self, value: &T) -> bool { self.map.remove(value) }
if b1 < a1 {
if !f(b1) { return }
y = y.next();
set_next(&mut y);
b = y.get();
} else {
if !f(a1) { return }
if !(a1 < b1) {
y = y.next();
set_next(&mut y);
b = y.get()
}
x = x.next();
set_next(&mut x);
a = x.get();
}
}
@ -524,16 +522,16 @@ impl <T: Ord> TreeSetIterator<T> {
/// Returns the current node, or None if this iterator is at the end.
fn get(&const self) -> Option<&self/T> {
match self.iter.get() {
None => None,
Some((k, _)) => Some(k)
None => None,
Some((k, _)) => Some(k)
}
}
}
/// Advance the iterator to the next node (in order). If this iterator is
/// finished, does nothing.
fn next(self) -> TreeSetIterator/&self<T> {
TreeSetIterator { iter: self.iter.next() }
}
/// Advance the iterator to the next node (in order). If this iterator is
/// finished, does nothing.
fn set_next<T: Ord>(iter: &mut TreeSetIterator/&a<T>) {
map_next(&mut iter.iter);
}
// Nodes keep track of their level in the tree, starting at 1 in the
@ -967,18 +965,18 @@ fn test_lazy_iterator() {
// FIXME: #4492 (ICE): iter.next() == Some((&x1, &y1))
iter = iter.next();
map_next(&mut iter);
assert iter.get().unwrap() == (&x1, &y1);
iter = iter.next();
map_next(&mut iter);
assert iter.get().unwrap() == (&x2, &y2);
iter = iter.next();
map_next(&mut iter);
assert iter.get().unwrap() == (&x3, &y3);
iter = iter.next();
map_next(&mut iter);
assert iter.get().unwrap() == (&x4, &y4);
iter = iter.next();
map_next(&mut iter);
assert iter.get().unwrap() == (&x5, &y5);
iter = iter.next();
map_next(&mut iter);
assert iter.get().is_none();
}
}