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// Copyright 2012 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.
/*!
* A simple map based on a vector for small integer keys. Space requirements
* are O(highest integer key).
*/
use core::container::{Container, Mutable, Map, Set};
use core::iter::{BaseIter, ReverseIter};
use core::option::{Some, None};
use core::prelude::*;
pub struct SmallIntMap<T> {
priv v: ~[Option<T>],
}
impl<V> BaseIter<(uint, &self/V)> for SmallIntMap<V> {
/// Visit all key-value pairs in order
pure fn each(&self, it: &fn(&(uint, &self/V)) -> bool) {
for uint::range(0, self.v.len()) |i| {
match self.v[i] {
Some(ref elt) => if !it(&(i, elt)) { break },
None => ()
}
}
}
pure fn size_hint(&self) -> Option<uint> { Some(self.len()) }
}
impl<V> ReverseIter<(uint, &self/V)> for SmallIntMap<V> {
/// Visit all key-value pairs in reverse order
pure fn each_reverse(&self, it: &fn(&(uint, &self/V)) -> bool) {
for uint::range_rev(self.v.len(), 0) |i| {
match self.v[i - 1] {
Some(ref elt) => if !it(&(i - 1, elt)) { break },
None => ()
}
}
}
}
impl<V> Container for SmallIntMap<V> {
/// Return the number of elements in the map
pure fn len(&self) -> uint {
let mut sz = 0;
for self.v.each |item| {
if item.is_some() {
sz += 1;
}
}
sz
}
/// Return true if the map contains no elements
pure fn is_empty(&self) -> bool { self.len() == 0 }
}
impl<V> Mutable for SmallIntMap<V> {
/// Clear the map, removing all key-value pairs.
fn clear(&mut self) { self.v.clear() }
}
impl<V> Map<uint, V> for SmallIntMap<V> {
/// Return true if the map contains a value for the specified key
pure fn contains_key(&self, key: &uint) -> bool {
self.find(key).is_some()
}
/// Visit all keys in order
pure fn each_key(&self, blk: &fn(key: &uint) -> bool) {
self.each(|&(k, _)| blk(&k))
}
/// Visit all values in order
pure fn each_value(&self, blk: &fn(value: &V) -> bool) {
self.each(|&(_, v)| blk(v))
}
/// Return the value corresponding to the key in the map
pure fn find(&self, key: &uint) -> Option<&self/V> {
if *key < self.v.len() {
match self.v[*key] {
Some(ref value) => Some(value),
None => None
}
} else {
None
}
}
/// Insert a key-value pair into the map. An existing value for a
/// key is replaced by the new value. Return true if the key did
/// not already exist in the map.
fn insert(&mut self, key: uint, value: V) -> bool {
let exists = self.contains_key(&key);
let len = self.v.len();
if len <= key {
vec::grow_fn(&mut self.v, key - len + 1, |_| None);
}
self.v[key] = Some(value);
!exists
}
/// Remove a key-value pair from the map. Return true if the key
/// was present in the map, otherwise false.
fn remove(&mut self, key: &uint) -> bool {
if *key >= self.v.len() {
return false;
}
let removed = self.v[*key].is_some();
self.v[*key] = None;
removed
}
}
pub impl<V> SmallIntMap<V> {
/// Create an empty SmallIntMap
static pure fn new() -> SmallIntMap<V> { SmallIntMap{v: ~[]} }
pure fn get(&self, key: &uint) -> &self/V {
self.find(key).expect("key not present")
}
}
pub impl<V:Copy> SmallIntMap<V> {
fn update_with_key(&mut self, key: uint, val: V,
ff: &fn(uint, V, V) -> V) -> bool {
let new_val = match self.find(&key) {
None => val,
Some(orig) => ff(key, *orig, val)
};
self.insert(key, new_val)
}
fn update(&mut self, key: uint, newval: V, ff: &fn(V, V) -> V) -> bool {
self.update_with_key(key, newval, |_k, v, v1| ff(v,v1))
}
}
#[cfg(test)]
mod tests {
use super::SmallIntMap;
#[test]
fn test_len() {
let mut map = SmallIntMap::new();
fail_unless!(map.len() == 0);
fail_unless!(map.is_empty());
fail_unless!(map.insert(5, 20));
fail_unless!(map.len() == 1);
fail_unless!(!map.is_empty());
fail_unless!(map.insert(11, 12));
fail_unless!(map.len() == 2);
fail_unless!(!map.is_empty());
fail_unless!(map.insert(14, 22));
fail_unless!(map.len() == 3);
fail_unless!(!map.is_empty());
}
#[test]
fn test_clear() {
let mut map = SmallIntMap::new();
fail_unless!(map.insert(5, 20));
fail_unless!(map.insert(11, 12));
fail_unless!(map.insert(14, 22));
map.clear();
fail_unless!(map.is_empty());
fail_unless!(map.find(&5).is_none());
fail_unless!(map.find(&11).is_none());
fail_unless!(map.find(&14).is_none());
}
#[test]
fn test_insert_with_key() {
let mut map = SmallIntMap::new();
// given a new key, initialize it with this new count, given
// given an existing key, add more to its count
fn addMoreToCount(_k: uint, v0: uint, v1: uint) -> uint {
v0 + v1
}
fn addMoreToCount_simple(v0: uint, v1: uint) -> uint {
v0 + v1
}
// count integers
map.update(3, 1, addMoreToCount_simple);
map.update_with_key(9, 1, addMoreToCount);
map.update(3, 7, addMoreToCount_simple);
map.update_with_key(5, 3, addMoreToCount);
map.update_with_key(3, 2, addMoreToCount);
// check the total counts
fail_unless!(map.find(&3).get() == &10);
fail_unless!(map.find(&5).get() == &3);
fail_unless!(map.find(&9).get() == &1);
// sadly, no sevens were counted
fail_unless!(map.find(&7).is_none());
}
}
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