rust/src/libcollections/trie.rs

1595 lines
47 KiB
Rust

// Copyright 2013-2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! Ordered containers with unsigned integer keys,
//! implemented as radix tries (`TrieSet` and `TrieMap` types).
use core::prelude::*;
use alloc::boxed::Box;
use core::default::Default;
use core::fmt;
use core::fmt::Show;
use core::mem::zeroed;
use core::mem;
use core::uint;
use core::iter;
use std::hash::{Writer, Hash};
use {Collection, Mutable, Map, MutableMap, Set, MutableSet};
use slice::{Items, MutItems};
use slice;
// FIXME: #5244: need to manually update the TrieNode constructor
static SHIFT: uint = 4;
static SIZE: uint = 1 << SHIFT;
static MASK: uint = SIZE - 1;
static NUM_CHUNKS: uint = uint::BITS / SHIFT;
#[deriving(Clone)]
enum Child<T> {
Internal(Box<TrieNode<T>>),
External(uint, T),
Nothing
}
/// A map implemented as a radix trie.
///
/// # Example
///
/// ```
/// use std::collections::TrieMap;
///
/// let mut map = TrieMap::new();
/// map.insert(27, "Olaf");
/// map.insert(1, "Edgar");
/// map.insert(13, "Ruth");
/// map.insert(1, "Martin");
///
/// assert_eq!(map.len(), 3);
/// assert_eq!(map.find(&1), Some(&"Martin"));
///
/// if !map.contains_key(&90) {
/// println!("Nobody is keyed 90");
/// }
///
/// // Update a key
/// match map.find_mut(&1) {
/// Some(value) => *value = "Olga",
/// None => (),
/// }
///
/// map.remove(&13);
/// assert_eq!(map.len(), 2);
///
/// // Print the key value pairs, ordered by key.
/// for (key, value) in map.iter() {
/// // Prints `1: Olga` then `27: Olaf`
/// println!("{}: {}", key, value);
/// }
///
/// map.clear();
/// assert!(map.is_empty());
/// ```
#[deriving(Clone)]
pub struct TrieMap<T> {
root: TrieNode<T>,
length: uint
}
impl<T: PartialEq> PartialEq for TrieMap<T> {
fn eq(&self, other: &TrieMap<T>) -> bool {
self.len() == other.len() &&
self.iter().zip(other.iter()).all(|(a, b)| a == b)
}
}
impl<T: Eq> Eq for TrieMap<T> {}
impl<T: PartialOrd> PartialOrd for TrieMap<T> {
#[inline]
fn partial_cmp(&self, other: &TrieMap<T>) -> Option<Ordering> {
iter::order::partial_cmp(self.iter(), other.iter())
}
}
impl<T: Ord> Ord for TrieMap<T> {
#[inline]
fn cmp(&self, other: &TrieMap<T>) -> Ordering {
iter::order::cmp(self.iter(), other.iter())
}
}
impl<T: Show> Show for TrieMap<T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
try!(write!(f, "{{"));
for (i, (k, v)) in self.iter().enumerate() {
if i != 0 { try!(write!(f, ", ")); }
try!(write!(f, "{}: {}", k, *v));
}
write!(f, "}}")
}
}
impl<T> Collection for TrieMap<T> {
/// Return the number of elements in the map.
#[inline]
fn len(&self) -> uint { self.length }
}
impl<T> Mutable for TrieMap<T> {
/// Clear the map, removing all values.
#[inline]
fn clear(&mut self) {
self.root = TrieNode::new();
self.length = 0;
}
}
impl<T> Map<uint, T> for TrieMap<T> {
/// Return a reference to the value corresponding to the key.
#[inline]
fn find<'a>(&'a self, key: &uint) -> Option<&'a T> {
let mut node: &'a TrieNode<T> = &self.root;
let mut idx = 0;
loop {
match node.children[chunk(*key, idx)] {
Internal(ref x) => node = &**x,
External(stored, ref value) => {
if stored == *key {
return Some(value)
} else {
return None
}
}
Nothing => return None
}
idx += 1;
}
}
}
impl<T> MutableMap<uint, T> for TrieMap<T> {
/// Return a mutable reference to the value corresponding to the key.
#[inline]
fn find_mut<'a>(&'a mut self, key: &uint) -> Option<&'a mut T> {
find_mut(&mut self.root.children[chunk(*key, 0)], *key, 1)
}
/// Insert a key-value pair from the map. If the key already had a value
/// present in the map, that value is returned. Otherwise None is returned.
fn swap(&mut self, key: uint, value: T) -> Option<T> {
let ret = insert(&mut self.root.count,
&mut self.root.children[chunk(key, 0)],
key, value, 1);
if ret.is_none() { self.length += 1 }
ret
}
/// Removes a key from the map, returning the value at the key if the key
/// was previously in the map.
fn pop(&mut self, key: &uint) -> Option<T> {
let ret = remove(&mut self.root.count,
&mut self.root.children[chunk(*key, 0)],
*key, 1);
if ret.is_some() { self.length -= 1 }
ret
}
}
impl<T> Default for TrieMap<T> {
#[inline]
fn default() -> TrieMap<T> { TrieMap::new() }
}
impl<T> TrieMap<T> {
/// Create an empty TrieMap.
///
/// # Example
///
/// ```
/// use std::collections::TrieMap;
/// let mut map: TrieMap<&str> = TrieMap::new();
/// ```
#[inline]
pub fn new() -> TrieMap<T> {
TrieMap{root: TrieNode::new(), length: 0}
}
/// Visit all key-value pairs in reverse order. Abort traversal when f returns false.
/// Return true if f returns true for all elements.
///
/// # Example
///
/// ```
/// use std::collections::TrieMap;
/// let map: TrieMap<&str> = [(1, "a"), (2, "b"), (3, "c")].iter().map(|&x| x).collect();
///
/// let mut vec = Vec::new();
/// assert_eq!(true, map.each_reverse(|&key, &value| { vec.push((key, value)); true }));
/// assert_eq!(vec, vec![(3, "c"), (2, "b"), (1, "a")]);
///
/// // Stop when we reach 2
/// let mut vec = Vec::new();
/// assert_eq!(false, map.each_reverse(|&key, &value| { vec.push(value); key != 2 }));
/// assert_eq!(vec, vec!["c", "b"]);
/// ```
#[inline]
pub fn each_reverse<'a>(&'a self, f: |&uint, &'a T| -> bool) -> bool {
self.root.each_reverse(f)
}
/// Get an iterator visiting all keys in ascending order by the keys.
/// Iterator element type is `uint`.
pub fn keys<'r>(&'r self) -> Keys<'r, T> {
self.iter().map(|(k, _v)| k)
}
/// Get an iterator visiting all values in ascending order by the keys.
/// Iterator element type is `&'r T`.
pub fn values<'r>(&'r self) -> Values<'r, T> {
self.iter().map(|(_k, v)| v)
}
/// Get an iterator over the key-value pairs in the map, ordered by keys.
///
/// # Example
///
/// ```
/// use std::collections::TrieMap;
/// let map: TrieMap<&str> = [(3, "c"), (1, "a"), (2, "b")].iter().map(|&x| x).collect();
///
/// for (key, value) in map.iter() {
/// println!("{}: {}", key, value);
/// }
/// ```
pub fn iter<'a>(&'a self) -> Entries<'a, T> {
let mut iter = unsafe {Entries::new()};
iter.stack[0] = self.root.children.iter();
iter.length = 1;
iter.remaining_min = self.length;
iter.remaining_max = self.length;
iter
}
/// Get an iterator over the key-value pairs in the map, with the
/// ability to mutate the values.
///
/// # Example
///
/// ```
/// use std::collections::TrieMap;
/// let mut map: TrieMap<int> = [(1, 2), (2, 4), (3, 6)].iter().map(|&x| x).collect();
///
/// for (key, value) in map.mut_iter() {
/// *value = -(key as int);
/// }
///
/// assert_eq!(map.find(&1), Some(&-1));
/// assert_eq!(map.find(&2), Some(&-2));
/// assert_eq!(map.find(&3), Some(&-3));
/// ```
pub fn mut_iter<'a>(&'a mut self) -> MutEntries<'a, T> {
let mut iter = unsafe {MutEntries::new()};
iter.stack[0] = self.root.children.mut_iter();
iter.length = 1;
iter.remaining_min = self.length;
iter.remaining_max = self.length;
iter
}
}
// FIXME #5846 we want to be able to choose between &x and &mut x
// (with many different `x`) below, so we need to optionally pass mut
// as a tt, but the only thing we can do with a `tt` is pass them to
// other macros, so this takes the `& <mutability> <operand>` token
// sequence and forces their evaluation as an expression. (see also
// `item!` below.)
macro_rules! addr { ($e:expr) => { $e } }
macro_rules! bound {
($iterator_name:ident,
// the current treemap
self = $this:expr,
// the key to look for
key = $key:expr,
// are we looking at the upper bound?
is_upper = $upper:expr,
// method names for slicing/iterating.
slice_from = $slice_from:ident,
iter = $iter:ident,
// see the comment on `addr!`, this is just an optional mut, but
// there's no 0-or-1 repeats yet.
mutability = $($mut_:tt)*) => {
{
// # For `mut`
// We need an unsafe pointer here because we are borrowing
// mutable references to the internals of each of these
// mutable nodes, while still using the outer node.
//
// However, we're allowed to flaunt rustc like this because we
// never actually modify the "shape" of the nodes. The only
// place that mutation is can actually occur is of the actual
// values of the TrieMap (as the return value of the
// iterator), i.e. we can never cause a deallocation of any
// TrieNodes so the raw pointer is always valid.
//
// # For non-`mut`
// We like sharing code so much that even a little unsafe won't
// stop us.
let this = $this;
let mut node = unsafe {
mem::transmute::<_, uint>(&this.root) as *mut TrieNode<T>
};
let key = $key;
let mut it = unsafe {$iterator_name::new()};
// everything else is zero'd, as we want.
it.remaining_max = this.length;
// this addr is necessary for the `Internal` pattern.
addr!(loop {
let children = unsafe {addr!(& $($mut_)* (*node).children)};
// it.length is the current depth in the iterator and the
// current depth through the `uint` key we've traversed.
let child_id = chunk(key, it.length);
let (slice_idx, ret) = match children[child_id] {
Internal(ref $($mut_)* n) => {
node = unsafe {
mem::transmute::<_, uint>(&**n)
as *mut TrieNode<T>
};
(child_id + 1, false)
}
External(stored, _) => {
(if stored < key || ($upper && stored == key) {
child_id + 1
} else {
child_id
}, true)
}
Nothing => {
(child_id + 1, true)
}
};
// push to the stack.
it.stack[it.length] = children.$slice_from(slice_idx).$iter();
it.length += 1;
if ret { return it }
})
}
}
}
impl<T> TrieMap<T> {
// If `upper` is true then returns upper_bound else returns lower_bound.
#[inline]
fn bound<'a>(&'a self, key: uint, upper: bool) -> Entries<'a, T> {
bound!(Entries, self = self,
key = key, is_upper = upper,
slice_from = slice_from, iter = iter,
mutability = )
}
/// Get an iterator pointing to the first key-value pair whose key is not less than `key`.
/// If all keys in the map are less than `key` an empty iterator is returned.
///
/// # Example
///
/// ```
/// use std::collections::TrieMap;
/// let map: TrieMap<&str> = [(2, "a"), (4, "b"), (6, "c")].iter().map(|&x| x).collect();
///
/// assert_eq!(map.lower_bound(4).next(), Some((4, &"b")));
/// assert_eq!(map.lower_bound(5).next(), Some((6, &"c")));
/// assert_eq!(map.lower_bound(10).next(), None);
/// ```
pub fn lower_bound<'a>(&'a self, key: uint) -> Entries<'a, T> {
self.bound(key, false)
}
/// Get an iterator pointing to the first key-value pair whose key is greater than `key`.
/// If all keys in the map are not greater than `key` an empty iterator is returned.
///
/// # Example
///
/// ```
/// use std::collections::TrieMap;
/// let map: TrieMap<&str> = [(2, "a"), (4, "b"), (6, "c")].iter().map(|&x| x).collect();
///
/// assert_eq!(map.upper_bound(4).next(), Some((6, &"c")));
/// assert_eq!(map.upper_bound(5).next(), Some((6, &"c")));
/// assert_eq!(map.upper_bound(10).next(), None);
/// ```
pub fn upper_bound<'a>(&'a self, key: uint) -> Entries<'a, T> {
self.bound(key, true)
}
// If `upper` is true then returns upper_bound else returns lower_bound.
#[inline]
fn mut_bound<'a>(&'a mut self, key: uint, upper: bool) -> MutEntries<'a, T> {
bound!(MutEntries, self = self,
key = key, is_upper = upper,
slice_from = mut_slice_from, iter = mut_iter,
mutability = mut)
}
/// Get an iterator pointing to the first key-value pair whose key is not less than `key`.
/// If all keys in the map are less than `key` an empty iterator is returned.
///
/// # Example
///
/// ```
/// use std::collections::TrieMap;
/// let mut map: TrieMap<&str> = [(2, "a"), (4, "b"), (6, "c")].iter().map(|&x| x).collect();
///
/// assert_eq!(map.mut_lower_bound(4).next(), Some((4, &mut "b")));
/// assert_eq!(map.mut_lower_bound(5).next(), Some((6, &mut "c")));
/// assert_eq!(map.mut_lower_bound(10).next(), None);
///
/// for (key, value) in map.mut_lower_bound(4) {
/// *value = "changed";
/// }
///
/// assert_eq!(map.find(&2), Some(&"a"));
/// assert_eq!(map.find(&4), Some(&"changed"));
/// assert_eq!(map.find(&6), Some(&"changed"));
/// ```
pub fn mut_lower_bound<'a>(&'a mut self, key: uint) -> MutEntries<'a, T> {
self.mut_bound(key, false)
}
/// Get an iterator pointing to the first key-value pair whose key is greater than `key`.
/// If all keys in the map are not greater than `key` an empty iterator is returned.
///
/// # Example
///
/// ```
/// use std::collections::TrieMap;
/// let mut map: TrieMap<&str> = [(2, "a"), (4, "b"), (6, "c")].iter().map(|&x| x).collect();
///
/// assert_eq!(map.mut_upper_bound(4).next(), Some((6, &mut "c")));
/// assert_eq!(map.mut_upper_bound(5).next(), Some((6, &mut "c")));
/// assert_eq!(map.mut_upper_bound(10).next(), None);
///
/// for (key, value) in map.mut_upper_bound(4) {
/// *value = "changed";
/// }
///
/// assert_eq!(map.find(&2), Some(&"a"));
/// assert_eq!(map.find(&4), Some(&"b"));
/// assert_eq!(map.find(&6), Some(&"changed"));
/// ```
pub fn mut_upper_bound<'a>(&'a mut self, key: uint) -> MutEntries<'a, T> {
self.mut_bound(key, true)
}
}
impl<T> FromIterator<(uint, T)> for TrieMap<T> {
fn from_iter<Iter: Iterator<(uint, T)>>(iter: Iter) -> TrieMap<T> {
let mut map = TrieMap::new();
map.extend(iter);
map
}
}
impl<T> Extendable<(uint, T)> for TrieMap<T> {
fn extend<Iter: Iterator<(uint, T)>>(&mut self, mut iter: Iter) {
for (k, v) in iter {
self.insert(k, v);
}
}
}
impl<S: Writer, T: Hash<S>> Hash<S> for TrieMap<T> {
fn hash(&self, state: &mut S) {
for elt in self.iter() {
elt.hash(state);
}
}
}
/// A set implemented as a radix trie.
///
/// # Example
///
/// ```
/// use std::collections::TrieSet;
///
/// let mut set = TrieSet::new();
/// set.insert(6);
/// set.insert(28);
/// set.insert(6);
///
/// assert_eq!(set.len(), 2);
///
/// if !set.contains(&3) {
/// println!("3 is not in the set");
/// }
///
/// // Print contents in order
/// for x in set.iter() {
/// println!("{}", x);
/// }
///
/// set.remove(&6);
/// assert_eq!(set.len(), 1);
///
/// set.clear();
/// assert!(set.is_empty());
/// ```
#[deriving(Clone, Hash, PartialEq, Eq, PartialOrd, Ord)]
pub struct TrieSet {
map: TrieMap<()>
}
impl Show for TrieSet {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
try!(write!(f, "{{"));
for (i, x) in self.iter().enumerate() {
if i != 0 { try!(write!(f, ", ")); }
try!(write!(f, "{}", x));
}
write!(f, "}}")
}
}
impl Collection for TrieSet {
/// Return the number of elements in the set.
#[inline]
fn len(&self) -> uint { self.map.len() }
}
impl Mutable for TrieSet {
/// Clear the set, removing all values.
#[inline]
fn clear(&mut self) { self.map.clear() }
}
impl Set<uint> for TrieSet {
#[inline]
fn contains(&self, value: &uint) -> bool {
self.map.contains_key(value)
}
#[inline]
fn is_disjoint(&self, other: &TrieSet) -> bool {
self.iter().all(|v| !other.contains(&v))
}
#[inline]
fn is_subset(&self, other: &TrieSet) -> bool {
self.iter().all(|v| other.contains(&v))
}
#[inline]
fn is_superset(&self, other: &TrieSet) -> bool {
other.is_subset(self)
}
}
impl MutableSet<uint> for TrieSet {
#[inline]
fn insert(&mut self, value: uint) -> bool {
self.map.insert(value, ())
}
#[inline]
fn remove(&mut self, value: &uint) -> bool {
self.map.remove(value)
}
}
impl Default for TrieSet {
#[inline]
fn default() -> TrieSet { TrieSet::new() }
}
impl TrieSet {
/// Create an empty TrieSet.
///
/// # Example
///
/// ```
/// use std::collections::TrieSet;
/// let mut set = TrieSet::new();
/// ```
#[inline]
pub fn new() -> TrieSet {
TrieSet{map: TrieMap::new()}
}
/// Visit all values in reverse order. Abort traversal when `f` returns false.
/// Return `true` if `f` returns `true` for all elements.
///
/// # Example
///
/// ```
/// use std::collections::TrieSet;
///
/// let set: TrieSet = [1, 2, 3, 4, 5].iter().map(|&x| x).collect();
///
/// let mut vec = Vec::new();
/// assert_eq!(true, set.each_reverse(|&x| { vec.push(x); true }));
/// assert_eq!(vec, vec![5, 4, 3, 2, 1]);
///
/// // Stop when we reach 3
/// let mut vec = Vec::new();
/// assert_eq!(false, set.each_reverse(|&x| { vec.push(x); x != 3 }));
/// assert_eq!(vec, vec![5, 4, 3]);
/// ```
#[inline]
pub fn each_reverse(&self, f: |&uint| -> bool) -> bool {
self.map.each_reverse(|k, _| f(k))
}
/// Get an iterator over the values in the set, in sorted order.
///
/// # Example
///
/// ```
/// use std::collections::TrieSet;
///
/// let mut set = TrieSet::new();
/// set.insert(3);
/// set.insert(2);
/// set.insert(1);
/// set.insert(2);
///
/// // Print 1, 2, 3
/// for x in set.iter() {
/// println!("{}", x);
/// }
/// ```
#[inline]
pub fn iter<'a>(&'a self) -> SetItems<'a> {
SetItems{iter: self.map.iter()}
}
/// Get an iterator pointing to the first value that is not less than `val`.
/// If all values in the set are less than `val` an empty iterator is returned.
///
/// # Example
///
/// ```
/// use std::collections::TrieSet;
///
/// let set: TrieSet = [2, 4, 6, 8].iter().map(|&x| x).collect();
/// assert_eq!(set.lower_bound(4).next(), Some(4));
/// assert_eq!(set.lower_bound(5).next(), Some(6));
/// assert_eq!(set.lower_bound(10).next(), None);
/// ```
pub fn lower_bound<'a>(&'a self, val: uint) -> SetItems<'a> {
SetItems{iter: self.map.lower_bound(val)}
}
/// Get an iterator pointing to the first value that key is greater than `val`.
/// If all values in the set are less than or equal to `val` an empty iterator is returned.
///
/// # Example
///
/// ```
/// use std::collections::TrieSet;
///
/// let set: TrieSet = [2, 4, 6, 8].iter().map(|&x| x).collect();
/// assert_eq!(set.upper_bound(4).next(), Some(6));
/// assert_eq!(set.upper_bound(5).next(), Some(6));
/// assert_eq!(set.upper_bound(10).next(), None);
/// ```
pub fn upper_bound<'a>(&'a self, val: uint) -> SetItems<'a> {
SetItems{iter: self.map.upper_bound(val)}
}
}
impl FromIterator<uint> for TrieSet {
fn from_iter<Iter: Iterator<uint>>(iter: Iter) -> TrieSet {
let mut set = TrieSet::new();
set.extend(iter);
set
}
}
impl Extendable<uint> for TrieSet {
fn extend<Iter: Iterator<uint>>(&mut self, mut iter: Iter) {
for elem in iter {
self.insert(elem);
}
}
}
struct TrieNode<T> {
count: uint,
children: [Child<T>, ..SIZE]
}
impl<T:Clone> Clone for TrieNode<T> {
#[inline]
fn clone(&self) -> TrieNode<T> {
let ch = &self.children;
TrieNode {
count: self.count,
children: [ch[0].clone(), ch[1].clone(), ch[2].clone(), ch[3].clone(),
ch[4].clone(), ch[5].clone(), ch[6].clone(), ch[7].clone(),
ch[8].clone(), ch[9].clone(), ch[10].clone(), ch[11].clone(),
ch[12].clone(), ch[13].clone(), ch[14].clone(), ch[15].clone()]}
}
}
impl<T> TrieNode<T> {
#[inline]
fn new() -> TrieNode<T> {
// FIXME: #5244: [Nothing, ..SIZE] should be possible without implicit
// copyability
TrieNode{count: 0,
children: [Nothing, Nothing, Nothing, Nothing,
Nothing, Nothing, Nothing, Nothing,
Nothing, Nothing, Nothing, Nothing,
Nothing, Nothing, Nothing, Nothing]}
}
}
impl<T> TrieNode<T> {
fn each_reverse<'a>(&'a self, f: |&uint, &'a T| -> bool) -> bool {
for elt in self.children.iter().rev() {
match *elt {
Internal(ref x) => if !x.each_reverse(|i,t| f(i,t)) { return false },
External(k, ref v) => if !f(&k, v) { return false },
Nothing => ()
}
}
true
}
}
// if this was done via a trait, the key could be generic
#[inline]
fn chunk(n: uint, idx: uint) -> uint {
let sh = uint::BITS - (SHIFT * (idx + 1));
(n >> sh) & MASK
}
fn find_mut<'r, T>(child: &'r mut Child<T>, key: uint, idx: uint) -> Option<&'r mut T> {
match *child {
External(stored, ref mut value) if stored == key => Some(value),
External(..) => None,
Internal(ref mut x) => find_mut(&mut x.children[chunk(key, idx)], key, idx + 1),
Nothing => None
}
}
fn insert<T>(count: &mut uint, child: &mut Child<T>, key: uint, value: T,
idx: uint) -> Option<T> {
// we branch twice to avoid having to do the `replace` when we
// don't need to; this is much faster, especially for keys that
// have long shared prefixes.
match *child {
Nothing => {
*count += 1;
*child = External(key, value);
return None;
}
Internal(ref mut x) => {
return insert(&mut x.count, &mut x.children[chunk(key, idx)], key, value, idx + 1);
}
External(stored_key, ref mut stored_value) if stored_key == key => {
// swap in the new value and return the old.
return Some(mem::replace(stored_value, value));
}
_ => {}
}
// conflict, an external node with differing keys: we have to
// split the node, so we need the old value by value; hence we
// have to move out of `child`.
match mem::replace(child, Nothing) {
External(stored_key, stored_value) => {
let mut new = box TrieNode::new();
insert(&mut new.count,
&mut new.children[chunk(stored_key, idx)],
stored_key, stored_value, idx + 1);
let ret = insert(&mut new.count, &mut new.children[chunk(key, idx)],
key, value, idx + 1);
*child = Internal(new);
return ret;
}
_ => fail!("unreachable code"),
}
}
fn remove<T>(count: &mut uint, child: &mut Child<T>, key: uint,
idx: uint) -> Option<T> {
let (ret, this) = match *child {
External(stored, _) if stored == key => {
match mem::replace(child, Nothing) {
External(_, value) => (Some(value), true),
_ => fail!()
}
}
External(..) => (None, false),
Internal(ref mut x) => {
let ret = remove(&mut x.count, &mut x.children[chunk(key, idx)],
key, idx + 1);
(ret, x.count == 0)
}
Nothing => (None, false)
};
if this {
*child = Nothing;
*count -= 1;
}
return ret;
}
/// Forward iterator over a map.
pub struct Entries<'a, T> {
stack: [slice::Items<'a, Child<T>>, .. NUM_CHUNKS],
length: uint,
remaining_min: uint,
remaining_max: uint
}
/// Forward iterator over the key-value pairs of a map, with the
/// values being mutable.
pub struct MutEntries<'a, T> {
stack: [slice::MutItems<'a, Child<T>>, .. NUM_CHUNKS],
length: uint,
remaining_min: uint,
remaining_max: uint
}
/// Forward iterator over the keys of a map
pub type Keys<'a, T> =
iter::Map<'static, (uint, &'a T), uint, Entries<'a, T>>;
/// Forward iterator over the values of a map
pub type Values<'a, T> =
iter::Map<'static, (uint, &'a T), &'a T, Entries<'a, T>>;
// FIXME #5846: see `addr!` above.
macro_rules! item { ($i:item) => {$i}}
macro_rules! iterator_impl {
($name:ident,
iter = $iter:ident,
mutability = $($mut_:tt)*) => {
impl<'a, T> $name<'a, T> {
// Create new zero'd iterator. We have a thin gilding of safety by
// using init rather than uninit, so that the worst that can happen
// from failing to initialise correctly after calling these is a
// segfault.
#[cfg(target_word_size="32")]
unsafe fn new() -> $name<'a, T> {
$name {
remaining_min: 0,
remaining_max: 0,
length: 0,
// ick :( ... at least the compiler will tell us if we screwed up.
stack: [zeroed(), zeroed(), zeroed(), zeroed(), zeroed(),
zeroed(), zeroed(), zeroed()]
}
}
#[cfg(target_word_size="64")]
unsafe fn new() -> $name<'a, T> {
$name {
remaining_min: 0,
remaining_max: 0,
length: 0,
stack: [zeroed(), zeroed(), zeroed(), zeroed(),
zeroed(), zeroed(), zeroed(), zeroed(),
zeroed(), zeroed(), zeroed(), zeroed(),
zeroed(), zeroed(), zeroed(), zeroed()]
}
}
}
item!(impl<'a, T> Iterator<(uint, &'a $($mut_)* T)> for $name<'a, T> {
// you might wonder why we're not even trying to act within the
// rules, and are just manipulating raw pointers like there's no
// such thing as invalid pointers and memory unsafety. The
// reason is performance, without doing this we can get the
// bench_iter_large microbenchmark down to about 30000 ns/iter
// (using .unsafe_ref to index self.stack directly, 38000
// ns/iter with [] checked indexing), but this smashes that down
// to 13500 ns/iter.
//
// Fortunately, it's still safe...
//
// We have an invariant that every Internal node
// corresponds to one push to self.stack, and one pop,
// nested appropriately. self.stack has enough storage
// to store the maximum depth of Internal nodes in the
// trie (8 on 32-bit platforms, 16 on 64-bit).
fn next(&mut self) -> Option<(uint, &'a $($mut_)* T)> {
let start_ptr = self.stack.as_mut_ptr();
unsafe {
// write_ptr is the next place to write to the stack.
// invariant: start_ptr <= write_ptr < end of the
// vector.
let mut write_ptr = start_ptr.offset(self.length as int);
while write_ptr != start_ptr {
// indexing back one is safe, since write_ptr >
// start_ptr now.
match (*write_ptr.offset(-1)).next() {
// exhausted this iterator (i.e. finished this
// Internal node), so pop from the stack.
//
// don't bother clearing the memory, because the
// next time we use it we'll've written to it
// first.
None => write_ptr = write_ptr.offset(-1),
Some(child) => {
addr!(match *child {
Internal(ref $($mut_)* node) => {
// going down a level, so push
// to the stack (this is the
// write referenced above)
*write_ptr = node.children.$iter();
write_ptr = write_ptr.offset(1);
}
External(key, ref $($mut_)* value) => {
self.remaining_max -= 1;
if self.remaining_min > 0 {
self.remaining_min -= 1;
}
// store the new length of the
// stack, based on our current
// position.
self.length = (write_ptr as uint
- start_ptr as uint) /
mem::size_of_val(&*write_ptr);
return Some((key, value));
}
Nothing => {}
})
}
}
}
}
return None;
}
#[inline]
fn size_hint(&self) -> (uint, Option<uint>) {
(self.remaining_min, Some(self.remaining_max))
}
})
}
}
iterator_impl! { Entries, iter = iter, mutability = }
iterator_impl! { MutEntries, iter = mut_iter, mutability = mut }
/// Forward iterator over a set.
pub struct SetItems<'a> {
iter: Entries<'a, ()>
}
impl<'a> Iterator<uint> for SetItems<'a> {
fn next(&mut self) -> Option<uint> {
self.iter.next().map(|(key, _)| key)
}
fn size_hint(&self) -> (uint, Option<uint>) {
self.iter.size_hint()
}
}
#[cfg(test)]
mod test_map {
use std::prelude::*;
use std::iter::range_step;
use std::uint;
use std::hash;
use {MutableMap, Map, MutableSeq};
use super::{TrieMap, TrieNode, Internal, External, Nothing};
fn check_integrity<T>(trie: &TrieNode<T>) {
assert!(trie.count != 0);
let mut sum = 0;
for x in trie.children.iter() {
match *x {
Nothing => (),
Internal(ref y) => {
check_integrity(&**y);
sum += 1
}
External(_, _) => { sum += 1 }
}
}
assert_eq!(sum, trie.count);
}
#[test]
fn test_find_mut() {
let mut m = TrieMap::new();
assert!(m.insert(1u, 12i));
assert!(m.insert(2u, 8i));
assert!(m.insert(5u, 14i));
let new = 100;
match m.find_mut(&5) {
None => fail!(), Some(x) => *x = new
}
assert_eq!(m.find(&5), Some(&new));
}
#[test]
fn test_find_mut_missing() {
let mut m = TrieMap::new();
assert!(m.find_mut(&0).is_none());
assert!(m.insert(1u, 12i));
assert!(m.find_mut(&0).is_none());
assert!(m.insert(2, 8));
assert!(m.find_mut(&0).is_none());
}
#[test]
fn test_step() {
let mut trie = TrieMap::new();
let n = 300u;
for x in range_step(1u, n, 2) {
assert!(trie.insert(x, x + 1));
assert!(trie.contains_key(&x));
check_integrity(&trie.root);
}
for x in range_step(0u, n, 2) {
assert!(!trie.contains_key(&x));
assert!(trie.insert(x, x + 1));
check_integrity(&trie.root);
}
for x in range(0u, n) {
assert!(trie.contains_key(&x));
assert!(!trie.insert(x, x + 1));
check_integrity(&trie.root);
}
for x in range_step(1u, n, 2) {
assert!(trie.remove(&x));
assert!(!trie.contains_key(&x));
check_integrity(&trie.root);
}
for x in range_step(0u, n, 2) {
assert!(trie.contains_key(&x));
assert!(!trie.insert(x, x + 1));
check_integrity(&trie.root);
}
}
#[test]
fn test_each_reverse() {
let mut m = TrieMap::new();
assert!(m.insert(3, 6));
assert!(m.insert(0, 0));
assert!(m.insert(4, 8));
assert!(m.insert(2, 4));
assert!(m.insert(1, 2));
let mut n = 4;
m.each_reverse(|k, v| {
assert_eq!(*k, n);
assert_eq!(*v, n * 2);
n -= 1;
true
});
}
#[test]
fn test_each_reverse_break() {
let mut m = TrieMap::new();
for x in range(uint::MAX - 10000, uint::MAX).rev() {
m.insert(x, x / 2);
}
let mut n = uint::MAX - 1;
m.each_reverse(|k, v| {
if n == uint::MAX - 5000 { false } else {
assert!(n > uint::MAX - 5000);
assert_eq!(*k, n);
assert_eq!(*v, n / 2);
n -= 1;
true
}
});
}
#[test]
fn test_swap() {
let mut m = TrieMap::new();
assert_eq!(m.swap(1u, 2i), None);
assert_eq!(m.swap(1u, 3i), Some(2));
assert_eq!(m.swap(1u, 4i), Some(3));
}
#[test]
fn test_pop() {
let mut m = TrieMap::new();
m.insert(1u, 2i);
assert_eq!(m.pop(&1), Some(2));
assert_eq!(m.pop(&1), None);
}
#[test]
fn test_from_iter() {
let xs = vec![(1u, 1i), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6)];
let map: TrieMap<int> = xs.iter().map(|&x| x).collect();
for &(k, v) in xs.iter() {
assert_eq!(map.find(&k), Some(&v));
}
}
#[test]
fn test_keys() {
let vec = vec![(1, 'a'), (2, 'b'), (3, 'c')];
let map = vec.move_iter().collect::<TrieMap<char>>();
let keys = map.keys().collect::<Vec<uint>>();
assert_eq!(keys.len(), 3);
assert!(keys.contains(&1));
assert!(keys.contains(&2));
assert!(keys.contains(&3));
}
#[test]
fn test_values() {
let vec = vec![(1, 'a'), (2, 'b'), (3, 'c')];
let map = vec.move_iter().collect::<TrieMap<char>>();
let values = map.values().map(|&v| v).collect::<Vec<char>>();
assert_eq!(values.len(), 3);
assert!(values.contains(&'a'));
assert!(values.contains(&'b'));
assert!(values.contains(&'c'));
}
#[test]
fn test_iteration() {
let empty_map : TrieMap<uint> = TrieMap::new();
assert_eq!(empty_map.iter().next(), None);
let first = uint::MAX - 10000;
let last = uint::MAX;
let mut map = TrieMap::new();
for x in range(first, last).rev() {
map.insert(x, x / 2);
}
let mut i = 0;
for (k, &v) in map.iter() {
assert_eq!(k, first + i);
assert_eq!(v, k / 2);
i += 1;
}
assert_eq!(i, last - first);
}
#[test]
fn test_mut_iter() {
let mut empty_map : TrieMap<uint> = TrieMap::new();
assert!(empty_map.mut_iter().next().is_none());
let first = uint::MAX - 10000;
let last = uint::MAX;
let mut map = TrieMap::new();
for x in range(first, last).rev() {
map.insert(x, x / 2);
}
let mut i = 0;
for (k, v) in map.mut_iter() {
assert_eq!(k, first + i);
*v -= k / 2;
i += 1;
}
assert_eq!(i, last - first);
assert!(map.iter().all(|(_, &v)| v == 0));
}
#[test]
fn test_bound() {
let empty_map : TrieMap<uint> = TrieMap::new();
assert_eq!(empty_map.lower_bound(0).next(), None);
assert_eq!(empty_map.upper_bound(0).next(), None);
let last = 999u;
let step = 3u;
let value = 42u;
let mut map : TrieMap<uint> = TrieMap::new();
for x in range_step(0u, last, step) {
assert!(x % step == 0);
map.insert(x, value);
}
for i in range(0u, last - step) {
let mut lb = map.lower_bound(i);
let mut ub = map.upper_bound(i);
let next_key = i - i % step + step;
let next_pair = (next_key, &value);
if i % step == 0 {
assert_eq!(lb.next(), Some((i, &value)));
} else {
assert_eq!(lb.next(), Some(next_pair));
}
assert_eq!(ub.next(), Some(next_pair));
}
let mut lb = map.lower_bound(last - step);
assert_eq!(lb.next(), Some((last - step, &value)));
let mut ub = map.upper_bound(last - step);
assert_eq!(ub.next(), None);
for i in range(last - step + 1, last) {
let mut lb = map.lower_bound(i);
assert_eq!(lb.next(), None);
let mut ub = map.upper_bound(i);
assert_eq!(ub.next(), None);
}
}
#[test]
fn test_mut_bound() {
let empty_map : TrieMap<uint> = TrieMap::new();
assert_eq!(empty_map.lower_bound(0).next(), None);
assert_eq!(empty_map.upper_bound(0).next(), None);
let mut m_lower = TrieMap::new();
let mut m_upper = TrieMap::new();
for i in range(0u, 100) {
m_lower.insert(2 * i, 4 * i);
m_upper.insert(2 * i, 4 * i);
}
for i in range(0u, 199) {
let mut lb_it = m_lower.mut_lower_bound(i);
let (k, v) = lb_it.next().unwrap();
let lb = i + i % 2;
assert_eq!(lb, k);
*v -= k;
}
for i in range(0u, 198) {
let mut ub_it = m_upper.mut_upper_bound(i);
let (k, v) = ub_it.next().unwrap();
let ub = i + 2 - i % 2;
assert_eq!(ub, k);
*v -= k;
}
assert!(m_lower.mut_lower_bound(199).next().is_none());
assert!(m_upper.mut_upper_bound(198).next().is_none());
assert!(m_lower.iter().all(|(_, &x)| x == 0));
assert!(m_upper.iter().all(|(_, &x)| x == 0));
}
#[test]
fn test_clone() {
let mut a = TrieMap::new();
a.insert(1, 'a');
a.insert(2, 'b');
a.insert(3, 'c');
assert!(a.clone() == a);
}
#[test]
fn test_eq() {
let mut a = TrieMap::new();
let mut b = TrieMap::new();
assert!(a == b);
assert!(a.insert(0, 5i));
assert!(a != b);
assert!(b.insert(0, 4i));
assert!(a != b);
assert!(a.insert(5, 19));
assert!(a != b);
assert!(!b.insert(0, 5));
assert!(a != b);
assert!(b.insert(5, 19));
assert!(a == b);
}
#[test]
fn test_lt() {
let mut a = TrieMap::new();
let mut b = TrieMap::new();
assert!(!(a < b) && !(b < a));
assert!(b.insert(2u, 5i));
assert!(a < b);
assert!(a.insert(2, 7));
assert!(!(a < b) && b < a);
assert!(b.insert(1, 0));
assert!(b < a);
assert!(a.insert(0, 6));
assert!(a < b);
assert!(a.insert(6, 2));
assert!(a < b && !(b < a));
}
#[test]
fn test_ord() {
let mut a = TrieMap::new();
let mut b = TrieMap::new();
assert!(a <= b && a >= b);
assert!(a.insert(1u, 1i));
assert!(a > b && a >= b);
assert!(b < a && b <= a);
assert!(b.insert(2, 2));
assert!(b > a && b >= a);
assert!(a < b && a <= b);
}
#[test]
fn test_hash() {
let mut x = TrieMap::new();
let mut y = TrieMap::new();
assert!(hash::hash(&x) == hash::hash(&y));
x.insert(1, 'a');
x.insert(2, 'b');
x.insert(3, 'c');
y.insert(3, 'c');
y.insert(2, 'b');
y.insert(1, 'a');
assert!(hash::hash(&x) == hash::hash(&y));
}
#[test]
fn test_show() {
let mut map = TrieMap::new();
let empty: TrieMap<uint> = TrieMap::new();
map.insert(1, 'a');
map.insert(2, 'b');
let map_str = format!("{}", map);
assert!(map_str == "{1: a, 2: b}".to_string());
assert_eq!(format!("{}", empty), "{}".to_string());
}
}
#[cfg(test)]
mod bench_map {
use std::prelude::*;
use std::rand::{weak_rng, Rng};
use test::Bencher;
use MutableMap;
use super::TrieMap;
#[bench]
fn bench_iter_small(b: &mut Bencher) {
let mut m = TrieMap::<uint>::new();
let mut rng = weak_rng();
for _ in range(0u, 20) {
m.insert(rng.gen(), rng.gen());
}
b.iter(|| for _ in m.iter() {})
}
#[bench]
fn bench_iter_large(b: &mut Bencher) {
let mut m = TrieMap::<uint>::new();
let mut rng = weak_rng();
for _ in range(0u, 1000) {
m.insert(rng.gen(), rng.gen());
}
b.iter(|| for _ in m.iter() {})
}
#[bench]
fn bench_lower_bound(b: &mut Bencher) {
let mut m = TrieMap::<uint>::new();
let mut rng = weak_rng();
for _ in range(0u, 1000) {
m.insert(rng.gen(), rng.gen());
}
b.iter(|| {
for _ in range(0u, 10) {
m.lower_bound(rng.gen());
}
});
}
#[bench]
fn bench_upper_bound(b: &mut Bencher) {
let mut m = TrieMap::<uint>::new();
let mut rng = weak_rng();
for _ in range(0u, 1000) {
m.insert(rng.gen(), rng.gen());
}
b.iter(|| {
for _ in range(0u, 10) {
m.upper_bound(rng.gen());
}
});
}
#[bench]
fn bench_insert_large(b: &mut Bencher) {
let mut m = TrieMap::<[uint, .. 10]>::new();
let mut rng = weak_rng();
b.iter(|| {
for _ in range(0u, 1000) {
m.insert(rng.gen(), [1, .. 10]);
}
})
}
#[bench]
fn bench_insert_large_low_bits(b: &mut Bencher) {
let mut m = TrieMap::<[uint, .. 10]>::new();
let mut rng = weak_rng();
b.iter(|| {
for _ in range(0u, 1000) {
// only have the last few bits set.
m.insert(rng.gen::<uint>() & 0xff_ff, [1, .. 10]);
}
})
}
#[bench]
fn bench_insert_small(b: &mut Bencher) {
let mut m = TrieMap::<()>::new();
let mut rng = weak_rng();
b.iter(|| {
for _ in range(0u, 1000) {
m.insert(rng.gen(), ());
}
})
}
#[bench]
fn bench_insert_small_low_bits(b: &mut Bencher) {
let mut m = TrieMap::<()>::new();
let mut rng = weak_rng();
b.iter(|| {
for _ in range(0u, 1000) {
// only have the last few bits set.
m.insert(rng.gen::<uint>() & 0xff_ff, ());
}
})
}
}
#[cfg(test)]
mod test_set {
use std::prelude::*;
use std::uint;
use {MutableSet, Set, MutableSeq};
use super::TrieSet;
#[test]
fn test_sane_chunk() {
let x = 1;
let y = 1 << (uint::BITS - 1);
let mut trie = TrieSet::new();
assert!(trie.insert(x));
assert!(trie.insert(y));
assert_eq!(trie.len(), 2);
let expected = [x, y];
for (i, x) in trie.iter().enumerate() {
assert_eq!(expected[i], x);
}
}
#[test]
fn test_from_iter() {
let xs = vec![9u, 8, 7, 6, 5, 4, 3, 2, 1];
let set: TrieSet = xs.iter().map(|&x| x).collect();
for x in xs.iter() {
assert!(set.contains(x));
}
}
#[test]
fn test_show() {
let mut set = TrieSet::new();
let empty = TrieSet::new();
set.insert(1);
set.insert(2);
let set_str = format!("{}", set);
assert!(set_str == "{1, 2}".to_string());
assert_eq!(format!("{}", empty), "{}".to_string());
}
#[test]
fn test_clone() {
let mut a = TrieSet::new();
a.insert(1);
a.insert(2);
a.insert(3);
assert!(a.clone() == a);
}
#[test]
fn test_lt() {
let mut a = TrieSet::new();
let mut b = TrieSet::new();
assert!(!(a < b) && !(b < a));
assert!(b.insert(2u));
assert!(a < b);
assert!(a.insert(3u));
assert!(!(a < b) && b < a);
assert!(b.insert(1));
assert!(b < a);
assert!(a.insert(0));
assert!(a < b);
assert!(a.insert(6));
assert!(a < b && !(b < a));
}
#[test]
fn test_ord() {
let mut a = TrieSet::new();
let mut b = TrieSet::new();
assert!(a <= b && a >= b);
assert!(a.insert(1u));
assert!(a > b && a >= b);
assert!(b < a && b <= a);
assert!(b.insert(2u));
assert!(b > a && b >= a);
assert!(a < b && a <= b);
}
}