507 lines
14 KiB
Rust
507 lines
14 KiB
Rust
// Copyright 2012 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 structure for holding a set of enum variants.
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//!
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//! This module defines a container which uses an efficient bit mask
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//! representation to hold C-like enum variants.
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use core::prelude::*;
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use core::fmt;
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use core::num::Int;
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// FIXME(contentions): implement union family of methods? (general design may be wrong here)
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#[deriving(Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
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/// A specialized set implementation to use enum types.
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pub struct EnumSet<E> {
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// We must maintain the invariant that no bits are set
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// for which no variant exists
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bits: uint
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}
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impl<E> Copy for EnumSet<E> {}
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impl<E:CLike+fmt::Show> fmt::Show for EnumSet<E> {
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fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
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try!(write!(fmt, "{{"));
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let mut first = true;
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for e in self.iter() {
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if !first {
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try!(write!(fmt, ", "));
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}
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try!(write!(fmt, "{}", e));
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first = false;
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}
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write!(fmt, "}}")
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}
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}
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/// An interface for casting C-like enum to uint and back.
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/// A typically implementation is as below.
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///
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/// ```{rust,ignore}
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/// #[repr(uint)]
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/// enum Foo {
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/// A, B, C
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/// }
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///
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/// impl CLike for Foo {
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/// fn to_uint(&self) -> uint {
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/// *self as uint
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/// }
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///
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/// fn from_uint(v: uint) -> Foo {
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/// unsafe { mem::transmute(v) }
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/// }
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/// }
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/// ```
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pub trait CLike {
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/// Converts a C-like enum to a `uint`.
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fn to_uint(&self) -> uint;
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/// Converts a `uint` to a C-like enum.
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fn from_uint(uint) -> Self;
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}
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fn bit<E:CLike>(e: &E) -> uint {
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use core::uint;
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let value = e.to_uint();
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assert!(value < uint::BITS,
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"EnumSet only supports up to {} variants.", uint::BITS - 1);
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1 << value
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}
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impl<E:CLike> EnumSet<E> {
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/// Deprecated: Renamed to `new`.
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#[deprecated = "Renamed to `new`"]
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pub fn empty() -> EnumSet<E> {
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EnumSet::new()
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}
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/// Returns an empty `EnumSet`.
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#[unstable = "matches collection reform specification, waiting for dust to settle"]
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pub fn new() -> EnumSet<E> {
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EnumSet {bits: 0}
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}
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/// Returns the number of elements in the given `EnumSet`.
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#[unstable = "matches collection reform specification, waiting for dust to settle"]
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pub fn len(&self) -> uint {
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self.bits.count_ones()
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}
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/// Returns true if the `EnumSet` is empty.
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#[unstable = "matches collection reform specification, waiting for dust to settle"]
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pub fn is_empty(&self) -> bool {
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self.bits == 0
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}
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pub fn clear(&mut self) {
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self.bits = 0;
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}
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/// Returns `true` if the `EnumSet` contains any enum of the given `EnumSet`.
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/// Deprecated: Use `is_disjoint`.
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#[deprecated = "Use `is_disjoint`"]
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pub fn intersects(&self, e: EnumSet<E>) -> bool {
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!self.is_disjoint(&e)
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}
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/// Returns `false` if the `EnumSet` contains any enum of the given `EnumSet`.
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#[unstable = "matches collection reform specification, waiting for dust to settle"]
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pub fn is_disjoint(&self, other: &EnumSet<E>) -> bool {
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(self.bits & other.bits) == 0
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}
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/// Returns `true` if a given `EnumSet` is included in this `EnumSet`.
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#[unstable = "matches collection reform specification, waiting for dust to settle"]
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pub fn is_superset(&self, other: &EnumSet<E>) -> bool {
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(self.bits & other.bits) == other.bits
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}
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/// Returns `true` if this `EnumSet` is included in the given `EnumSet`.
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#[unstable = "matches collection reform specification, waiting for dust to settle"]
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pub fn is_subset(&self, other: &EnumSet<E>) -> bool {
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other.is_superset(self)
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}
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/// Returns the union of both `EnumSets`.
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pub fn union(&self, e: EnumSet<E>) -> EnumSet<E> {
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EnumSet {bits: self.bits | e.bits}
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}
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/// Returns the intersection of both `EnumSets`.
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pub fn intersection(&self, e: EnumSet<E>) -> EnumSet<E> {
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EnumSet {bits: self.bits & e.bits}
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}
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/// Deprecated: Use `insert`.
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#[deprecated = "Use `insert`"]
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pub fn add(&mut self, e: E) {
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self.insert(e);
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}
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/// Adds an enum to the `EnumSet`, and returns `true` if it wasn't there before
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#[unstable = "matches collection reform specification, waiting for dust to settle"]
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pub fn insert(&mut self, e: E) -> bool {
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let result = !self.contains(&e);
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self.bits |= bit(&e);
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result
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}
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/// Removes an enum from the EnumSet
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#[unstable = "matches collection reform specification, waiting for dust to settle"]
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pub fn remove(&mut self, e: &E) -> bool {
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let result = self.contains(e);
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self.bits &= !bit(e);
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result
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}
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/// Deprecated: use `contains`.
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#[deprecated = "use `contains"]
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pub fn contains_elem(&self, e: E) -> bool {
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self.contains(&e)
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}
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/// Returns `true` if an `EnumSet` contains a given enum.
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#[unstable = "matches collection reform specification, waiting for dust to settle"]
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pub fn contains(&self, e: &E) -> bool {
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(self.bits & bit(e)) != 0
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}
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/// Returns an iterator over an `EnumSet`.
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#[unstable = "matches collection reform specification, waiting for dust to settle"]
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pub fn iter(&self) -> Iter<E> {
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Iter::new(self.bits)
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}
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}
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impl<E:CLike> Sub<EnumSet<E>, EnumSet<E>> for EnumSet<E> {
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fn sub(self, e: EnumSet<E>) -> EnumSet<E> {
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EnumSet {bits: self.bits & !e.bits}
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}
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}
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impl<E:CLike> BitOr<EnumSet<E>, EnumSet<E>> for EnumSet<E> {
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fn bitor(self, e: EnumSet<E>) -> EnumSet<E> {
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EnumSet {bits: self.bits | e.bits}
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}
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}
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impl<E:CLike> BitAnd<EnumSet<E>, EnumSet<E>> for EnumSet<E> {
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fn bitand(self, e: EnumSet<E>) -> EnumSet<E> {
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EnumSet {bits: self.bits & e.bits}
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}
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}
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impl<E:CLike> BitXor<EnumSet<E>, EnumSet<E>> for EnumSet<E> {
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fn bitxor(self, e: EnumSet<E>) -> EnumSet<E> {
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EnumSet {bits: self.bits ^ e.bits}
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}
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}
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/// An iterator over an EnumSet
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pub struct Iter<E> {
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index: uint,
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bits: uint,
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}
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// FIXME(#19839) Remove in favor of `#[deriving(Clone)]`
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impl<E> Clone for Iter<E> {
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fn clone(&self) -> Iter<E> {
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Iter {
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index: self.index,
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bits: self.bits,
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}
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}
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}
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impl<E:CLike> Iter<E> {
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fn new(bits: uint) -> Iter<E> {
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Iter { index: 0, bits: bits }
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}
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}
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impl<E:CLike> Iterator<E> for Iter<E> {
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fn next(&mut self) -> Option<E> {
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if self.bits == 0 {
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return None;
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}
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while (self.bits & 1) == 0 {
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self.index += 1;
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self.bits >>= 1;
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}
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let elem = CLike::from_uint(self.index);
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self.index += 1;
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self.bits >>= 1;
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Some(elem)
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}
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fn size_hint(&self) -> (uint, Option<uint>) {
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let exact = self.bits.count_ones();
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(exact, Some(exact))
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}
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}
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impl<E:CLike> FromIterator<E> for EnumSet<E> {
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fn from_iter<I:Iterator<E>>(iterator: I) -> EnumSet<E> {
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let mut ret = EnumSet::new();
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ret.extend(iterator);
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ret
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}
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}
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impl<E:CLike> Extend<E> for EnumSet<E> {
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fn extend<I: Iterator<E>>(&mut self, mut iterator: I) {
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for element in iterator {
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self.insert(element);
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}
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}
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}
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#[cfg(test)]
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mod test {
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use self::Foo::*;
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use prelude::*;
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use core::mem;
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use super::{EnumSet, CLike};
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#[deriving(Copy, PartialEq, Show)]
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#[repr(uint)]
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enum Foo {
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A, B, C
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}
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impl CLike for Foo {
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fn to_uint(&self) -> uint {
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*self as uint
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}
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fn from_uint(v: uint) -> Foo {
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unsafe { mem::transmute(v) }
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}
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}
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#[test]
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fn test_new() {
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let e: EnumSet<Foo> = EnumSet::new();
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assert!(e.is_empty());
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}
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#[test]
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fn test_show() {
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let mut e = EnumSet::new();
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assert_eq!("{}", e.to_string());
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e.insert(A);
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assert_eq!("{A}", e.to_string());
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e.insert(C);
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assert_eq!("{A, C}", e.to_string());
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}
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#[test]
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fn test_len() {
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let mut e = EnumSet::new();
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assert_eq!(e.len(), 0);
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e.insert(A);
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e.insert(B);
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e.insert(C);
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assert_eq!(e.len(), 3);
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e.remove(&A);
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assert_eq!(e.len(), 2);
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e.clear();
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assert_eq!(e.len(), 0);
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}
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///////////////////////////////////////////////////////////////////////////
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// intersect
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#[test]
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fn test_two_empties_do_not_intersect() {
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let e1: EnumSet<Foo> = EnumSet::new();
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let e2: EnumSet<Foo> = EnumSet::new();
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assert!(e1.is_disjoint(&e2));
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}
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#[test]
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fn test_empty_does_not_intersect_with_full() {
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let e1: EnumSet<Foo> = EnumSet::new();
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let mut e2: EnumSet<Foo> = EnumSet::new();
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e2.insert(A);
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e2.insert(B);
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e2.insert(C);
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assert!(e1.is_disjoint(&e2));
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}
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#[test]
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fn test_disjoint_intersects() {
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let mut e1: EnumSet<Foo> = EnumSet::new();
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e1.insert(A);
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let mut e2: EnumSet<Foo> = EnumSet::new();
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e2.insert(B);
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assert!(e1.is_disjoint(&e2));
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}
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#[test]
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fn test_overlapping_intersects() {
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let mut e1: EnumSet<Foo> = EnumSet::new();
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e1.insert(A);
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let mut e2: EnumSet<Foo> = EnumSet::new();
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e2.insert(A);
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e2.insert(B);
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assert!(!e1.is_disjoint(&e2));
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}
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///////////////////////////////////////////////////////////////////////////
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// contains and contains_elem
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#[test]
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fn test_superset() {
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let mut e1: EnumSet<Foo> = EnumSet::new();
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e1.insert(A);
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let mut e2: EnumSet<Foo> = EnumSet::new();
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e2.insert(A);
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e2.insert(B);
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let mut e3: EnumSet<Foo> = EnumSet::new();
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e3.insert(C);
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assert!(e1.is_subset(&e2));
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assert!(e2.is_superset(&e1));
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assert!(!e3.is_superset(&e2));
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assert!(!e2.is_superset(&e3))
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}
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#[test]
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fn test_contains() {
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let mut e1: EnumSet<Foo> = EnumSet::new();
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e1.insert(A);
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assert!(e1.contains(&A));
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assert!(!e1.contains(&B));
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assert!(!e1.contains(&C));
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e1.insert(A);
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e1.insert(B);
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assert!(e1.contains(&A));
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assert!(e1.contains(&B));
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assert!(!e1.contains(&C));
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}
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///////////////////////////////////////////////////////////////////////////
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// iter
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#[test]
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fn test_iterator() {
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let mut e1: EnumSet<Foo> = EnumSet::new();
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let elems: ::vec::Vec<Foo> = e1.iter().collect();
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assert!(elems.is_empty());
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e1.insert(A);
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let elems: ::vec::Vec<_> = e1.iter().collect();
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assert_eq!(vec![A], elems);
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e1.insert(C);
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let elems: ::vec::Vec<_> = e1.iter().collect();
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assert_eq!(vec![A,C], elems);
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e1.insert(C);
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let elems: ::vec::Vec<_> = e1.iter().collect();
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assert_eq!(vec![A,C], elems);
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e1.insert(B);
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let elems: ::vec::Vec<_> = e1.iter().collect();
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assert_eq!(vec![A,B,C], elems);
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}
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///////////////////////////////////////////////////////////////////////////
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// operators
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#[test]
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fn test_operators() {
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let mut e1: EnumSet<Foo> = EnumSet::new();
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e1.insert(A);
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e1.insert(C);
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let mut e2: EnumSet<Foo> = EnumSet::new();
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e2.insert(B);
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e2.insert(C);
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let e_union = e1 | e2;
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let elems: ::vec::Vec<_> = e_union.iter().collect();
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assert_eq!(vec![A,B,C], elems);
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let e_intersection = e1 & e2;
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let elems: ::vec::Vec<_> = e_intersection.iter().collect();
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assert_eq!(vec![C], elems);
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// Another way to express intersection
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let e_intersection = e1 - (e1 - e2);
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let elems: ::vec::Vec<_> = e_intersection.iter().collect();
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assert_eq!(vec![C], elems);
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let e_subtract = e1 - e2;
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let elems: ::vec::Vec<_> = e_subtract.iter().collect();
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assert_eq!(vec![A], elems);
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// Bitwise XOR of two sets, aka symmetric difference
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let e_symmetric_diff = e1 ^ e2;
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let elems: ::vec::Vec<_> = e_symmetric_diff.iter().collect();
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assert_eq!(vec![A,B], elems);
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// Another way to express symmetric difference
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let e_symmetric_diff = (e1 - e2) | (e2 - e1);
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let elems: ::vec::Vec<_> = e_symmetric_diff.iter().collect();
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assert_eq!(vec![A,B], elems);
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// Yet another way to express symmetric difference
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let e_symmetric_diff = (e1 | e2) - (e1 & e2);
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let elems: ::vec::Vec<_> = e_symmetric_diff.iter().collect();
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assert_eq!(vec![A,B], elems);
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}
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#[test]
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#[should_fail]
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fn test_overflow() {
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#[allow(dead_code)]
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#[deriving(Copy)]
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#[repr(uint)]
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enum Bar {
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V00, V01, V02, V03, V04, V05, V06, V07, V08, V09,
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V10, V11, V12, V13, V14, V15, V16, V17, V18, V19,
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V20, V21, V22, V23, V24, V25, V26, V27, V28, V29,
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V30, V31, V32, V33, V34, V35, V36, V37, V38, V39,
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V40, V41, V42, V43, V44, V45, V46, V47, V48, V49,
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V50, V51, V52, V53, V54, V55, V56, V57, V58, V59,
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V60, V61, V62, V63, V64, V65, V66, V67, V68, V69,
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}
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impl CLike for Bar {
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fn to_uint(&self) -> uint {
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*self as uint
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}
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fn from_uint(v: uint) -> Bar {
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unsafe { mem::transmute(v) }
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}
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}
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let mut set = EnumSet::new();
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set.insert(Bar::V64);
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}
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}
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