std: Implement Extendable for hashmap, str and trie

src/libstd/hashmap.rs

@@ -19,7 +19,7 @@ use container::{Container, Mutable, Map, MutableMap, Set, MutableSet};
 use clone::Clone;
 use cmp::{Eq, Equiv};
 use hash::Hash;
-use iterator::{Iterator, IteratorUtil, FromIterator, Chain};
+use iterator::{Iterator, IteratorUtil, FromIterator, Extendable, Chain};
 use num;
 use option::{None, Option, Some};
 use rand::RngUtil;
@@ -618,18 +618,22 @@ impl<K> Iterator<K> for HashSetConsumeIterator<K> {
 }
 
 impl<K: Eq + Hash, V, T: Iterator<(K, V)>> FromIterator<(K, V), T> for HashMap<K, V> {
-    pub fn from_iterator(iter: &mut T) -> HashMap<K, V> {
+    fn from_iterator(iter: &mut T) -> HashMap<K, V> {
         let (lower, _) = iter.size_hint();
         let mut map = HashMap::with_capacity(lower);
-
+        map.extend(iter);
-        for iter.advance |(k, v)| {
-            map.insert(k, v);
-        }
-
         map
     }
 }
 
+impl<K: Eq + Hash, V, T: Iterator<(K, V)>> Extendable<(K, V), T> for HashMap<K, V> {
+    fn extend(&mut self, iter: &mut T) {
+        for iter.advance |(k, v)| {
+            self.insert(k, v);
+        }
+    }
+}
+
 /// An implementation of a hash set using the underlying representation of a
 /// HashMap where the value is (). As with the `HashMap` type, a `HashSet`
 /// requires that the elements implement the `Eq` and `Hash` traits.
@@ -771,18 +775,22 @@ impl<T:Hash + Eq> HashSet<T> {
 }
 
 impl<K: Eq + Hash, T: Iterator<K>> FromIterator<K, T> for HashSet<K> {
-    pub fn from_iterator(iter: &mut T) -> HashSet<K> {
+    fn from_iterator(iter: &mut T) -> HashSet<K> {
         let (lower, _) = iter.size_hint();
         let mut set = HashSet::with_capacity(lower);
-
+        set.extend(iter);
-        for iter.advance |k| {
-            set.insert(k);
-        }
-
         set
     }
 }
 
+impl<K: Eq + Hash, T: Iterator<K>> Extendable<K, T> for HashSet<K> {
+    fn extend(&mut self, iter: &mut T) {
+        for iter.advance |k| {
+            self.insert(k);
+        }
+    }
+}
+
 // FIXME #7814: use std::iterator::FilterIterator
 /// Building block for Set operation iterators
 pub struct EnvFilterIterator<A, Env, I> {

src/libstd/str.rs

@@ -23,7 +23,8 @@ use char::Char;
 use clone::Clone;
 use container::{Container, Mutable};
 use iter::Times;
-use iterator::{Iterator, FromIterator, IteratorUtil, Filter, AdditiveIterator, Map};
+use iterator::{Iterator, FromIterator, Extendable, IteratorUtil};
+use iterator::{Filter, AdditiveIterator, Map};
 use libc;
 use num::Zero;
 use option::{None, Option, Some};
@@ -2323,13 +2324,23 @@ impl<T: Iterator<char>> FromIterator<char, T> for ~str {
     fn from_iterator(iterator: &mut T) -> ~str {
         let (lower, _) = iterator.size_hint();
         let mut buf = with_capacity(lower);
-        for iterator.advance |ch| {
+        buf.extend(iterator);
-            buf.push_char(ch)
-        }
         buf
     }
 }
 
+impl<T: Iterator<char>> Extendable<char, T> for ~str {
+    #[inline]
+    fn extend(&mut self, iterator: &mut T) {
+        let (lower, _) = iterator.size_hint();
+        let reserve = lower + self.len();
+        self.reserve_at_least(reserve);
+        for iterator.advance |ch| {
+            self.push_char(ch)
+        }
+    }
+}
+
 // This works because every lifetime is a sub-lifetime of 'static
 impl<'self> Zero for &'self str {
     fn zero() -> &'self str { "" }
@@ -2503,6 +2514,16 @@ mod tests {
         assert_eq!(data, s.as_slice());
     }
 
+    #[test]
+    fn test_extend() {
+        let data = ~"ประเทศไทย中";
+        let mut cpy = data.clone();
+        let other = "abc";
+        let mut it = other.iter();
+        cpy.extend(&mut it);
+        assert_eq!(cpy, data + other);
+    }
+
     #[test]
     fn test_clear() {
         let mut empty = ~"";

src/libstd/trie.rs

@@ -11,7 +11,7 @@
 //! An ordered map and set for integer keys implemented as a radix trie
 
 use prelude::*;
-use iterator::{IteratorUtil, FromIterator};
+use iterator::{IteratorUtil, FromIterator, Extendable};
 use uint;
 use util::{swap, replace};
 
@@ -155,17 +155,21 @@ impl<T> TrieMap<T> {
 }
 
 impl<T, Iter: Iterator<(uint, T)>> FromIterator<(uint, T), Iter> for TrieMap<T> {
-    pub fn from_iterator(iter: &mut Iter) -> TrieMap<T> {
+    fn from_iterator(iter: &mut Iter) -> TrieMap<T> {
         let mut map = TrieMap::new();
-
+        map.extend(iter);
-        for iter.advance |(k, v)| {
-            map.insert(k, v);
-        }
-
         map
     }
 }
 
+impl<T, Iter: Iterator<(uint, T)>> Extendable<(uint, T), Iter> for TrieMap<T> {
+    fn extend(&mut self, iter: &mut Iter) {
+        for iter.advance |(k, v)| {
+            self.insert(k, v);
+        }
+    }
+}
+
 #[allow(missing_doc)]
 pub struct TrieSet {
     priv map: TrieMap<()>
@@ -222,17 +226,21 @@ impl TrieSet {
 }
 
 impl<Iter: Iterator<uint>> FromIterator<uint, Iter> for TrieSet {
-    pub fn from_iterator(iter: &mut Iter) -> TrieSet {
+    fn from_iterator(iter: &mut Iter) -> TrieSet {
         let mut set = TrieSet::new();
-
+        set.extend(iter);
-        for iter.advance |elem| {
-            set.insert(elem);
-        }
-
         set
     }
 }
 
+impl<Iter: Iterator<uint>> Extendable<uint, Iter> for TrieSet {
+    fn extend(&mut self, iter: &mut Iter) {
+        for iter.advance |elem| {
+            self.insert(elem);
+        }
+    }
+}
+
 struct TrieNode<T> {
     count: uint,
     children: [Child<T>, ..SIZE]