492 lines
13 KiB
Rust
492 lines
13 KiB
Rust
// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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//! A radix trie for storing integers in sorted order
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use prelude::*;
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// FIXME: #5244: need to manually update the TrieNode constructor
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const SHIFT: uint = 4;
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const SIZE: uint = 1 << SHIFT;
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const MASK: uint = SIZE - 1;
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enum Child<T> {
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Internal(~TrieNode<T>),
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External(uint, T),
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Nothing
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}
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pub struct TrieMap<T> {
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priv root: TrieNode<T>,
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priv length: uint
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}
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impl<T> BaseIter<(uint, &'self T)> for TrieMap<T> {
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/// Visit all key-value pairs in order
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#[inline(always)]
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fn each(&self, f: &fn(&(uint, &'self T)) -> bool) {
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self.root.each(f);
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}
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#[inline(always)]
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fn size_hint(&self) -> Option<uint> { Some(self.len()) }
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}
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impl<T> ReverseIter<(uint, &'self T)> for TrieMap<T> {
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/// Visit all key-value pairs in reverse order
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#[inline(always)]
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fn each_reverse(&self, f: &fn(&(uint, &'self T)) -> bool) {
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self.root.each_reverse(f);
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}
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}
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impl<T> Container for TrieMap<T> {
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/// Return the number of elements in the map
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#[inline(always)]
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fn len(&const self) -> uint { self.length }
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/// Return true if the map contains no elements
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#[inline(always)]
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fn is_empty(&const self) -> bool { self.len() == 0 }
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}
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impl<T> Mutable for TrieMap<T> {
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/// Clear the map, removing all values.
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#[inline(always)]
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fn clear(&mut self) {
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self.root = TrieNode::new();
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self.length = 0;
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}
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}
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impl<T> Map<uint, T> for TrieMap<T> {
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/// Return true if the map contains a value for the specified key
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#[inline(always)]
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fn contains_key(&self, key: &uint) -> bool {
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self.find(key).is_some()
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}
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/// Visit all keys in order
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#[inline(always)]
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fn each_key(&self, f: &fn(&uint) -> bool) {
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self.each(|&(k, _)| f(&k))
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}
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/// Visit all values in order
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#[inline(always)]
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fn each_value(&self, f: &fn(&T) -> bool) {
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self.each(|&(_, v)| f(v))
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}
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/// Iterate over the map and mutate the contained values
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#[inline(always)]
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fn mutate_values(&mut self, f: &fn(&uint, &mut T) -> bool) {
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self.root.mutate_values(f);
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}
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/// Return the value corresponding to the key in the map
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#[inline(hint)]
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fn find(&self, key: &uint) -> Option<&'self T> {
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let mut node: &'self TrieNode<T> = &self.root;
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let mut idx = 0;
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loop {
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match node.children[chunk(*key, idx)] {
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Internal(ref x) => node = &**x,
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External(stored, ref value) => {
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if stored == *key {
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return Some(value)
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} else {
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return None
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}
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}
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Nothing => return None
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}
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idx += 1;
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}
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}
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/// Insert a key-value pair into the map. An existing value for a
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/// key is replaced by the new value. Return true if the key did
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/// not already exist in the map.
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#[inline(always)]
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fn insert(&mut self, key: uint, value: T) -> bool {
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let ret = insert(&mut self.root.count,
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&mut self.root.children[chunk(key, 0)],
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key, value, 1);
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if ret { self.length += 1 }
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ret
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}
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/// Remove a key-value pair from the map. Return true if the key
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/// was present in the map, otherwise false.
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#[inline(always)]
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fn remove(&mut self, key: &uint) -> bool {
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let ret = remove(&mut self.root.count,
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&mut self.root.children[chunk(*key, 0)],
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*key, 1);
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if ret { self.length -= 1 }
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ret
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}
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}
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pub impl<T> TrieMap<T> {
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/// Create an empty TrieMap
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#[inline(always)]
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fn new() -> TrieMap<T> {
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TrieMap{root: TrieNode::new(), length: 0}
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}
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/// Visit all keys in reverse order
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#[inline(always)]
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fn each_key_reverse(&self, f: &fn(&uint) -> bool) {
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self.each_reverse(|&(k, _)| f(&k))
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}
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/// Visit all values in reverse order
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#[inline(always)]
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fn each_value_reverse(&self, f: &fn(&T) -> bool) {
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self.each_reverse(|&(_, v)| f(v))
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}
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}
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pub struct TrieSet {
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priv map: TrieMap<()>
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}
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impl BaseIter<uint> for TrieSet {
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/// Visit all values in order
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fn each(&self, f: &fn(&uint) -> bool) { self.map.each_key(f) }
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fn size_hint(&self) -> Option<uint> { Some(self.len()) }
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}
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impl ReverseIter<uint> for TrieSet {
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/// Visit all values in reverse order
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fn each_reverse(&self, f: &fn(&uint) -> bool) {
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self.map.each_key_reverse(f)
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}
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}
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impl Container for TrieSet {
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/// Return the number of elements in the set
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#[inline(always)]
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fn len(&const self) -> uint { self.map.len() }
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/// Return true if the set contains no elements
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#[inline(always)]
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fn is_empty(&const self) -> bool { self.map.is_empty() }
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}
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impl Mutable for TrieSet {
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/// Clear the set, removing all values.
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#[inline(always)]
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fn clear(&mut self) { self.map.clear() }
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}
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impl TrieSet {
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/// Create an empty TrieSet
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#[inline(always)]
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fn new() -> TrieSet {
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TrieSet{map: TrieMap::new()}
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}
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/// Return true if the set contains a value
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#[inline(always)]
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fn contains(&self, value: &uint) -> bool {
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self.map.contains_key(value)
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}
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/// Add a value to the set. Return true if the value was not already
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/// present in the set.
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#[inline(always)]
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fn insert(&mut self, value: uint) -> bool { self.map.insert(value, ()) }
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/// Remove a value from the set. Return true if the value was
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/// present in the set.
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#[inline(always)]
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fn remove(&mut self, value: &uint) -> bool { self.map.remove(value) }
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}
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struct TrieNode<T> {
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count: uint,
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children: [Child<T> * SIZE]
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}
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impl<T> TrieNode<T> {
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#[inline(always)]
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fn new() -> TrieNode<T> {
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// FIXME: #5244: [Nothing, ..SIZE] should be possible without Copy
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TrieNode{count: 0,
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children: [Nothing, Nothing, Nothing, Nothing,
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Nothing, Nothing, Nothing, Nothing,
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Nothing, Nothing, Nothing, Nothing,
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Nothing, Nothing, Nothing, Nothing]}
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}
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}
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impl<T> TrieNode<T> {
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fn each(&self, f: &fn(&(uint, &'self T)) -> bool) -> bool {
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for uint::range(0, self.children.len()) |idx| {
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match self.children[idx] {
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Internal(ref x) => if !x.each(f) { return false },
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External(k, ref v) => if !f(&(k, v)) { return false },
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Nothing => ()
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}
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}
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true
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}
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fn each_reverse(&self, f: &fn(&(uint, &'self T)) -> bool) -> bool {
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for uint::range_rev(self.children.len(), 0) |idx| {
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match self.children[idx - 1] {
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Internal(ref x) => if !x.each_reverse(f) { return false },
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External(k, ref v) => if !f(&(k, v)) { return false },
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Nothing => ()
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}
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}
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true
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}
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fn mutate_values(&mut self, f: &fn(&uint, &mut T) -> bool) -> bool {
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for vec::each_mut(self.children) |child| {
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match *child {
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Internal(ref mut x) => if !x.mutate_values(f) {
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return false
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},
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External(k, ref mut v) => if !f(&k, v) { return false },
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Nothing => ()
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}
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}
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true
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}
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}
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// if this was done via a trait, the key could be generic
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#[inline(always)]
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fn chunk(n: uint, idx: uint) -> uint {
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let sh = uint::bits - (SHIFT * (idx + 1));
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(n >> sh) & MASK
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}
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fn insert<T>(count: &mut uint, child: &mut Child<T>, key: uint, value: T,
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idx: uint) -> bool {
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let mut tmp = Nothing;
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tmp <-> *child;
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let mut added = false;
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*child = match tmp {
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External(stored_key, stored_value) => {
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if stored_key == key {
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External(stored_key, value)
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} else {
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// conflict - split the node
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let mut new = ~TrieNode::new();
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insert(&mut new.count,
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&mut new.children[chunk(stored_key, idx)],
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stored_key, stored_value, idx + 1);
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insert(&mut new.count, &mut new.children[chunk(key, idx)], key,
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value, idx + 1);
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added = true;
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Internal(new)
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}
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}
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Internal(x) => {
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let mut x = x;
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added = insert(&mut x.count, &mut x.children[chunk(key, idx)], key,
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value, idx + 1);
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Internal(x)
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}
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Nothing => {
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*count += 1;
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added = true;
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External(key, value)
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}
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};
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added
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}
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fn remove<T>(count: &mut uint, child: &mut Child<T>, key: uint,
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idx: uint) -> bool {
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let (ret, this) = match *child {
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External(stored, _) => {
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if stored == key { (true, true) } else { (false, false) }
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}
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Internal(ref mut x) => {
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let ret = remove(&mut x.count, &mut x.children[chunk(key, idx)],
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key, idx + 1);
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(ret, x.count == 0)
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}
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Nothing => (false, false)
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};
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if this {
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*child = Nothing;
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*count -= 1;
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}
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ret
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}
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#[cfg(test)]
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pub fn check_integrity<T>(trie: &TrieNode<T>) {
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fail_unless!(trie.count != 0);
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let mut sum = 0;
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for trie.children.each |x| {
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match *x {
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Nothing => (),
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Internal(ref y) => {
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check_integrity(&**y);
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sum += 1
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}
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External(_, _) => { sum += 1 }
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}
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}
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fail_unless!(sum == trie.count);
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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use uint;
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#[test]
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fn test_step() {
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let mut trie = TrieMap::new();
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let n = 300;
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for uint::range_step(1, n, 2) |x| {
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fail_unless!(trie.insert(x, x + 1));
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fail_unless!(trie.contains_key(&x));
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check_integrity(&trie.root);
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}
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for uint::range_step(0, n, 2) |x| {
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fail_unless!(!trie.contains_key(&x));
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fail_unless!(trie.insert(x, x + 1));
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check_integrity(&trie.root);
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}
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for uint::range(0, n) |x| {
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fail_unless!(trie.contains_key(&x));
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fail_unless!(!trie.insert(x, x + 1));
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check_integrity(&trie.root);
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}
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for uint::range_step(1, n, 2) |x| {
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fail_unless!(trie.remove(&x));
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fail_unless!(!trie.contains_key(&x));
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check_integrity(&trie.root);
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}
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for uint::range_step(0, n, 2) |x| {
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fail_unless!(trie.contains_key(&x));
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fail_unless!(!trie.insert(x, x + 1));
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check_integrity(&trie.root);
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}
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}
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#[test]
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fn test_each() {
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let mut m = TrieMap::new();
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fail_unless!(m.insert(3, 6));
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fail_unless!(m.insert(0, 0));
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fail_unless!(m.insert(4, 8));
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fail_unless!(m.insert(2, 4));
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fail_unless!(m.insert(1, 2));
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let mut n = 0;
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for m.each |&(k, v)| {
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fail_unless!(k == n);
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fail_unless!(*v == n * 2);
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n += 1;
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}
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}
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#[test]
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fn test_each_break() {
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let mut m = TrieMap::new();
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for uint::range_rev(uint::max_value, uint::max_value - 10000) |x| {
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m.insert(x, x / 2);
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}
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let mut n = uint::max_value - 9999;
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for m.each |&(k, v)| {
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if n == uint::max_value - 5000 { break }
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fail_unless!(n < uint::max_value - 5000);
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fail_unless!(k == n);
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fail_unless!(*v == n / 2);
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n += 1;
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}
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}
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#[test]
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fn test_each_reverse() {
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let mut m = TrieMap::new();
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fail_unless!(m.insert(3, 6));
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fail_unless!(m.insert(0, 0));
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fail_unless!(m.insert(4, 8));
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fail_unless!(m.insert(2, 4));
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fail_unless!(m.insert(1, 2));
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let mut n = 4;
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for m.each_reverse |&(k, v)| {
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fail_unless!(k == n);
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fail_unless!(*v == n * 2);
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n -= 1;
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}
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}
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#[test]
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fn test_each_reverse_break() {
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let mut m = TrieMap::new();
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for uint::range_rev(uint::max_value, uint::max_value - 10000) |x| {
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m.insert(x, x / 2);
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}
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let mut n = uint::max_value;
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for m.each_reverse |&(k, v)| {
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if n == uint::max_value - 5000 { break }
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fail_unless!(n > uint::max_value - 5000);
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fail_unless!(k == n);
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fail_unless!(*v == n / 2);
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n -= 1;
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}
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}
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#[test]
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fn test_sane_chunk() {
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let x = 1;
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let y = 1 << (uint::bits - 1);
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let mut trie = TrieSet::new();
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fail_unless!(trie.insert(x));
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fail_unless!(trie.insert(y));
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fail_unless!(trie.len() == 2);
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let expected = [x, y];
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let mut i = 0;
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for trie.each |x| {
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fail_unless!(expected[i] == *x);
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i += 1;
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}
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}
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}
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