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extra: Simplify Eq/Ord in treemap

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Write the Eq and Ord impls for TreeMap in a more straightforward way
using iterator::Zip
This commit is contained in:
blake2-ppc 2013-08-06 17:27:39 +02:00 committed by Corey Richardson
parent 240f8f03c9
commit 4ab05f91f4
1 changed files with 5 additions and 21 deletions
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26
src/libextra/treemap.rs
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@ -42,39 +42,23 @@ pub struct TreeMap<K, V> {
impl<K: Eq + TotalOrd, V: Eq> Eq for TreeMap<K, V> {
fn eq(&self, other: &TreeMap<K, V>) -> bool {
if self.len() != other.len() {
false
} else {
let mut x = self.iter();
let mut y = other.iter();
for _ in range(0u, self.len()) {
if x.next().unwrap() != y.next().unwrap() {
return false
}
}
true
}
self.len() == other.len() &&
self.iter().zip(other.iter()).all(|(a, b)| a == b)
}
fn ne(&self, other: &TreeMap<K, V>) -> bool { !self.eq(other) }
}
// Lexicographical comparison
fn lt<K: Ord + TotalOrd, V: Ord>(a: &TreeMap<K, V>,
b: &TreeMap<K, V>) -> bool {
let mut x = a.iter();
let mut y = b.iter();
let (a_len, b_len) = (a.len(), b.len());
for _ in range(0u, num::min(a_len, b_len)) {
let (key_a, value_a) = x.next().unwrap();
let (key_b, value_b) = y.next().unwrap();
// the Zip iterator is as long as the shortest of a and b.
for ((key_a, value_a), (key_b, value_b)) in a.iter().zip(b.iter()) {
if *key_a < *key_b { return true; }
if *key_a > *key_b { return false; }
if *value_a < *value_b { return true; }
if *value_a > *value_b { return false; }
}
a_len < b_len
a.len() < b.len()
}
impl<K: Ord + TotalOrd, V: Ord> Ord for TreeMap<K, V> {