rust/src/libstd/smallintmap.rs
2013-01-31 23:13:56 -05:00

238 lines
6.4 KiB
Rust

// 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).
*/
#[forbid(deprecated_mode)];
use core::container::{Container, Mutable, Map, Set};
use core::dvec::DVec;
use core::ops;
use core::option::{Some, None};
use core::option;
use core::prelude::*;
// FIXME (#2347): Should not be @; there's a bug somewhere in rustc that
// requires this to be.
struct SmallIntMap_<T> {
v: DVec<Option<T>>,
}
pub enum SmallIntMap<T> {
SmallIntMap_(@SmallIntMap_<T>)
}
/// Create a smallintmap
pub fn mk<T: Copy>() -> SmallIntMap<T> {
let v = DVec();
SmallIntMap_(@SmallIntMap_ { v: v } )
}
/**
* Add a value to the map. If the map already contains a value for
* the specified key then the original value is replaced.
*/
#[inline(always)]
pub fn insert<T: Copy>(self: SmallIntMap<T>, key: uint, val: T) {
//io::println(fmt!("%?", key));
self.v.grow_set_elt(key, &None, Some(val));
}
/**
* Get the value for the specified key. If the key does not exist
* in the map then returns none
*/
pub pure fn find<T: Copy>(self: SmallIntMap<T>, key: uint) -> Option<T> {
if key < self.v.len() { return self.v.get_elt(key); }
return None::<T>;
}
/**
* Get the value for the specified key
*
* # Failure
*
* If the key does not exist in the map
*/
pub pure fn get<T: Copy>(self: SmallIntMap<T>, key: uint) -> T {
match find(self, key) {
None => {
error!("smallintmap::get(): key not present");
fail;
}
Some(move v) => return v
}
}
/// Returns true if the map contains a value for the specified key
pub pure fn contains_key<T: Copy>(self: SmallIntMap<T>, key: uint) -> bool {
return !find(self, key).is_none();
}
impl<V> SmallIntMap<V>: Container {
/// Return the number of elements in the map
pure fn len(&self) -> uint {
let mut sz = 0u;
for self.v.each |item| {
match *item {
Some(_) => sz += 1u,
_ => ()
}
}
sz
}
/// Return true if the map contains no elements
pure fn is_empty(&self) -> bool { self.len() == 0 }
}
impl<V> SmallIntMap<V>: Mutable {
fn clear(&mut self) { self.v.set(~[]) }
}
/// Implements the map::map interface for smallintmap
impl<V: Copy> SmallIntMap<V> {
#[inline(always)]
fn insert(key: uint, value: V) -> bool {
let exists = contains_key(self, key);
insert(self, key, value);
return !exists;
}
fn remove(key: uint) -> bool {
if key >= self.v.len() {
return false;
}
let old = self.v.get_elt(key);
self.v.set_elt(key, None);
old.is_some()
}
pure fn contains_key(key: uint) -> bool {
contains_key(self, key)
}
pure fn contains_key_ref(key: &uint) -> bool {
contains_key(self, *key)
}
pure fn get(key: uint) -> V { get(self, key) }
pure fn find(key: uint) -> Option<V> { find(self, key) }
fn update_with_key(key: uint, val: V, ff: fn(uint, V, V) -> V) -> bool {
match self.find(key) {
None => return self.insert(key, val),
Some(copy orig) => return self.insert(key, ff(key, orig, val)),
}
}
fn update(key: uint, newval: V, ff: fn(V, V) -> V) -> bool {
return self.update_with_key(key, newval, |_k, v, v1| ff(v,v1));
}
pure fn each(it: fn(key: uint, value: V) -> bool) {
self.each_ref(|k, v| it(*k, *v))
}
pure fn each_key(it: fn(key: uint) -> bool) {
self.each_ref(|k, _v| it(*k))
}
pure fn each_value(it: fn(value: V) -> bool) {
self.each_ref(|_k, v| it(*v))
}
pure fn each_ref(it: fn(key: &uint, value: &V) -> bool) {
let mut idx = 0u, l = self.v.len();
while idx < l {
match self.v.get_elt(idx) {
Some(ref elt) => if !it(&idx, elt) { break },
None => ()
}
idx += 1u;
}
}
pure fn each_key_ref(blk: fn(key: &uint) -> bool) {
self.each_ref(|k, _v| blk(k))
}
pure fn each_value_ref(blk: fn(value: &V) -> bool) {
self.each_ref(|_k, v| blk(v))
}
}
impl<V: Copy> SmallIntMap<V>: ops::Index<uint, V> {
pure fn index(&self, key: uint) -> V {
unsafe {
get(*self, key)
}
}
}
#[cfg(test)]
mod tests {
use super::{mk, SmallIntMap};
use core::option::None;
#[test]
fn test_len() {
let mut map = mk();
assert map.len() == 0;
assert map.is_empty();
map.insert(5, 20);
assert map.len() == 1;
assert !map.is_empty();
map.insert(11, 12);
assert map.len() == 2;
assert !map.is_empty();
map.insert(14, 22);
assert map.len() == 3;
assert !map.is_empty();
}
#[test]
fn test_clear() {
let mut map = mk();
map.insert(5, 20);
map.insert(11, 12);
map.insert(14, 22);
map.clear();
assert map.is_empty();
assert map.find(5).is_none();
assert map.find(11).is_none();
assert map.find(14).is_none();
}
#[test]
fn test_insert_with_key() {
let map: SmallIntMap<uint> = mk();
// 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
assert map.find(3).get() == 10;
assert map.find(5).get() == 3;
assert map.find(9).get() == 1;
// sadly, no sevens were counted
assert None == map.find(7);
}
}