rust/src/libcollections/enum_set.rs
2014-11-06 18:16:18 -08:00

433 lines
12 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 structure for holding a set of enum variants.
//!
//! This module defines a container which uses an efficient bit mask
//! representation to hold C-like enum variants.
use core::prelude::*;
use core::fmt;
// FIXME(conventions): implement BitXor
// FIXME(contentions): implement union family of methods? (general design may be wrong here)
// FIXME(conventions): implement len
#[deriving(Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
/// A specialized `Set` implementation to use enum types.
pub struct EnumSet<E> {
// We must maintain the invariant that no bits are set
// for which no variant exists
bits: uint
}
impl<E:CLike+fmt::Show> fmt::Show for EnumSet<E> {
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
try!(write!(fmt, "{{"));
let mut first = true;
for e in self.iter() {
if !first {
try!(write!(fmt, ", "));
}
try!(write!(fmt, "{}", e));
first = false;
}
write!(fmt, "}}")
}
}
/**
An interface for casting C-like enum to uint and back.
A typically implementation is as below.
```{rust,ignore}
#[repr(uint)]
enum Foo {
A, B, C
}
impl CLike for Foo {
fn to_uint(&self) -> uint {
*self as uint
}
fn from_uint(v: uint) -> Foo {
unsafe { mem::transmute(v) }
}
}
```
*/
pub trait CLike {
/// Converts a C-like enum to a `uint`.
fn to_uint(&self) -> uint;
/// Converts a `uint` to a C-like enum.
fn from_uint(uint) -> Self;
}
fn bit<E:CLike>(e: &E) -> uint {
use core::uint;
let value = e.to_uint();
assert!(value < uint::BITS,
"EnumSet only supports up to {} variants.", uint::BITS - 1);
1 << value
}
impl<E:CLike> EnumSet<E> {
/// Deprecated: Renamed to `new`.
#[deprecated = "Renamed to `new`"]
pub fn empty() -> EnumSet<E> {
EnumSet::new()
}
/// Returns an empty `EnumSet`.
#[unstable = "matches collection reform specification, waiting for dust to settle"]
pub fn new() -> EnumSet<E> {
EnumSet {bits: 0}
}
/// Returns true if the `EnumSet` is empty.
#[unstable = "matches collection reform specification, waiting for dust to settle"]
pub fn is_empty(&self) -> bool {
self.bits == 0
}
pub fn clear(&mut self) {
self.bits = 0;
}
/// Returns `true` if the `EnumSet` contains any enum of the given `EnumSet`.
/// Deprecated: Use `is_disjoint`.
#[deprecated = "Use `is_disjoint`"]
pub fn intersects(&self, e: EnumSet<E>) -> bool {
!self.is_disjoint(&e)
}
/// Returns `false` if the `EnumSet` contains any enum of the given `EnumSet`.
#[unstable = "matches collection reform specification, waiting for dust to settle"]
pub fn is_disjoint(&self, other: &EnumSet<E>) -> bool {
(self.bits & other.bits) == 0
}
/// Returns `true` if a given `EnumSet` is included in this `EnumSet`.
#[unstable = "matches collection reform specification, waiting for dust to settle"]
pub fn is_superset(&self, other: &EnumSet<E>) -> bool {
(self.bits & other.bits) == other.bits
}
/// Returns `true` if this `EnumSet` is included in the given `EnumSet`.
#[unstable = "matches collection reform specification, waiting for dust to settle"]
pub fn is_subset(&self, other: &EnumSet<E>) -> bool {
other.is_superset(self)
}
/// Returns the union of both `EnumSets`.
pub fn union(&self, e: EnumSet<E>) -> EnumSet<E> {
EnumSet {bits: self.bits | e.bits}
}
/// Returns the intersection of both `EnumSets`.
pub fn intersection(&self, e: EnumSet<E>) -> EnumSet<E> {
EnumSet {bits: self.bits & e.bits}
}
/// Deprecated: Use `insert`.
#[deprecated = "Use `insert`"]
pub fn add(&mut self, e: E) {
self.insert(e);
}
/// Adds an enum to the `EnumSet`, and returns `true` if it wasn't there before
#[unstable = "matches collection reform specification, waiting for dust to settle"]
pub fn insert(&mut self, e: E) -> bool {
let result = !self.contains(&e);
self.bits |= bit(&e);
result
}
/// Removes an enum from the EnumSet
#[unstable = "matches collection reform specification, waiting for dust to settle"]
pub fn remove(&mut self, e: &E) -> bool {
let result = self.contains(e);
self.bits &= !bit(e);
result
}
/// Deprecated: use `contains`.
#[deprecated = "use `contains"]
pub fn contains_elem(&self, e: E) -> bool {
self.contains(&e)
}
/// Returns `true` if an `EnumSet` contains a given enum.
#[unstable = "matches collection reform specification, waiting for dust to settle"]
pub fn contains(&self, e: &E) -> bool {
(self.bits & bit(e)) != 0
}
/// Returns an iterator over an `EnumSet`.
#[unstable = "matches collection reform specification, waiting for dust to settle"]
pub fn iter(&self) -> Items<E> {
Items::new(self.bits)
}
}
impl<E:CLike> Sub<EnumSet<E>, EnumSet<E>> for EnumSet<E> {
fn sub(&self, e: &EnumSet<E>) -> EnumSet<E> {
EnumSet {bits: self.bits & !e.bits}
}
}
impl<E:CLike> BitOr<EnumSet<E>, EnumSet<E>> for EnumSet<E> {
fn bitor(&self, e: &EnumSet<E>) -> EnumSet<E> {
EnumSet {bits: self.bits | e.bits}
}
}
impl<E:CLike> BitAnd<EnumSet<E>, EnumSet<E>> for EnumSet<E> {
fn bitand(&self, e: &EnumSet<E>) -> EnumSet<E> {
EnumSet {bits: self.bits & e.bits}
}
}
/// An iterator over an EnumSet
pub struct Items<E> {
index: uint,
bits: uint,
}
impl<E:CLike> Items<E> {
fn new(bits: uint) -> Items<E> {
Items { index: 0, bits: bits }
}
}
impl<E:CLike> Iterator<E> for Items<E> {
fn next(&mut self) -> Option<E> {
if self.bits == 0 {
return None;
}
while (self.bits & 1) == 0 {
self.index += 1;
self.bits >>= 1;
}
let elem = CLike::from_uint(self.index);
self.index += 1;
self.bits >>= 1;
Some(elem)
}
fn size_hint(&self) -> (uint, Option<uint>) {
let exact = self.bits.count_ones();
(exact, Some(exact))
}
}
#[cfg(test)]
mod test {
use std::prelude::*;
use std::mem;
use super::{EnumSet, CLike};
#[deriving(PartialEq, Show)]
#[repr(uint)]
enum Foo {
A, B, C
}
impl CLike for Foo {
fn to_uint(&self) -> uint {
*self as uint
}
fn from_uint(v: uint) -> Foo {
unsafe { mem::transmute(v) }
}
}
#[test]
fn test_new() {
let e: EnumSet<Foo> = EnumSet::new();
assert!(e.is_empty());
}
#[test]
fn test_show() {
let mut e = EnumSet::new();
assert_eq!("{}", e.to_string().as_slice());
e.insert(A);
assert_eq!("{A}", e.to_string().as_slice());
e.insert(C);
assert_eq!("{A, C}", e.to_string().as_slice());
}
///////////////////////////////////////////////////////////////////////////
// intersect
#[test]
fn test_two_empties_do_not_intersect() {
let e1: EnumSet<Foo> = EnumSet::new();
let e2: EnumSet<Foo> = EnumSet::new();
assert!(e1.is_disjoint(&e2));
}
#[test]
fn test_empty_does_not_intersect_with_full() {
let e1: EnumSet<Foo> = EnumSet::new();
let mut e2: EnumSet<Foo> = EnumSet::new();
e2.insert(A);
e2.insert(B);
e2.insert(C);
assert!(e1.is_disjoint(&e2));
}
#[test]
fn test_disjoint_intersects() {
let mut e1: EnumSet<Foo> = EnumSet::new();
e1.insert(A);
let mut e2: EnumSet<Foo> = EnumSet::new();
e2.insert(B);
assert!(e1.is_disjoint(&e2));
}
#[test]
fn test_overlapping_intersects() {
let mut e1: EnumSet<Foo> = EnumSet::new();
e1.insert(A);
let mut e2: EnumSet<Foo> = EnumSet::new();
e2.insert(A);
e2.insert(B);
assert!(!e1.is_disjoint(&e2));
}
///////////////////////////////////////////////////////////////////////////
// contains and contains_elem
#[test]
fn test_superset() {
let mut e1: EnumSet<Foo> = EnumSet::new();
e1.insert(A);
let mut e2: EnumSet<Foo> = EnumSet::new();
e2.insert(A);
e2.insert(B);
let mut e3: EnumSet<Foo> = EnumSet::new();
e3.insert(C);
assert!(e1.is_subset(&e2));
assert!(e2.is_superset(&e1));
assert!(!e3.is_superset(&e2))
assert!(!e2.is_superset(&e3))
}
#[test]
fn test_contains() {
let mut e1: EnumSet<Foo> = EnumSet::new();
e1.insert(A);
assert!(e1.contains(&A));
assert!(!e1.contains(&B));
assert!(!e1.contains(&C));
e1.insert(A);
e1.insert(B);
assert!(e1.contains(&A));
assert!(e1.contains(&B));
assert!(!e1.contains(&C));
}
///////////////////////////////////////////////////////////////////////////
// iter
#[test]
fn test_iterator() {
let mut e1: EnumSet<Foo> = EnumSet::new();
let elems: Vec<Foo> = e1.iter().collect();
assert!(elems.is_empty())
e1.insert(A);
let elems = e1.iter().collect();
assert_eq!(vec![A], elems)
e1.insert(C);
let elems = e1.iter().collect();
assert_eq!(vec![A,C], elems)
e1.insert(C);
let elems = e1.iter().collect();
assert_eq!(vec![A,C], elems)
e1.insert(B);
let elems = e1.iter().collect();
assert_eq!(vec![A,B,C], elems)
}
///////////////////////////////////////////////////////////////////////////
// operators
#[test]
fn test_operators() {
let mut e1: EnumSet<Foo> = EnumSet::new();
e1.insert(A);
e1.insert(C);
let mut e2: EnumSet<Foo> = EnumSet::new();
e2.insert(B);
e2.insert(C);
let e_union = e1 | e2;
let elems = e_union.iter().collect();
assert_eq!(vec![A,B,C], elems)
let e_intersection = e1 & e2;
let elems = e_intersection.iter().collect();
assert_eq!(vec![C], elems)
let e_subtract = e1 - e2;
let elems = e_subtract.iter().collect();
assert_eq!(vec![A], elems)
}
#[test]
#[should_fail]
fn test_overflow() {
#[allow(dead_code)]
#[repr(uint)]
enum Bar {
V00, V01, V02, V03, V04, V05, V06, V07, V08, V09,
V10, V11, V12, V13, V14, V15, V16, V17, V18, V19,
V20, V21, V22, V23, V24, V25, V26, V27, V28, V29,
V30, V31, V32, V33, V34, V35, V36, V37, V38, V39,
V40, V41, V42, V43, V44, V45, V46, V47, V48, V49,
V50, V51, V52, V53, V54, V55, V56, V57, V58, V59,
V60, V61, V62, V63, V64, V65, V66, V67, V68, V69,
}
impl CLike for Bar {
fn to_uint(&self) -> uint {
*self as uint
}
fn from_uint(v: uint) -> Bar {
unsafe { mem::transmute(v) }
}
}
let mut set = EnumSet::empty();
set.add(V64);
}
}