66613e26b9
This breaks all implementors of FromIterator, as they must now accept IntoIterator instead of Iterator. The fix for this is generally trivial (change the bound, and maybe call into_iter() on the argument to get the old argument). Users of FromIterator should be unaffected because Iterators are IntoIterator. [breaking-change]
515 lines
14 KiB
Rust
515 lines
14 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;
|
|
use core::num::Int;
|
|
use core::iter::{FromIterator, IntoIterator};
|
|
use core::ops::{Sub, BitOr, BitAnd, BitXor};
|
|
|
|
// FIXME(contentions): implement union family of methods? (general design may be wrong here)
|
|
|
|
#[derive(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: usize
|
|
}
|
|
|
|
impl<E> Copy for EnumSet<E> {}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<E:CLike + fmt::Debug> fmt::Debug for EnumSet<E> {
|
|
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
|
|
try!(write!(fmt, "EnumSet {{"));
|
|
let mut first = true;
|
|
for e in self {
|
|
if !first {
|
|
try!(write!(fmt, ", "));
|
|
}
|
|
try!(write!(fmt, "{:?}", e));
|
|
first = false;
|
|
}
|
|
write!(fmt, "}}")
|
|
}
|
|
}
|
|
|
|
/// An interface for casting C-like enum to usize and back.
|
|
/// A typically implementation is as below.
|
|
///
|
|
/// ```{rust,ignore}
|
|
/// #[repr(usize)]
|
|
/// enum Foo {
|
|
/// A, B, C
|
|
/// }
|
|
///
|
|
/// impl CLike for Foo {
|
|
/// fn to_usize(&self) -> usize {
|
|
/// *self as usize
|
|
/// }
|
|
///
|
|
/// fn from_usize(v: usize) -> Foo {
|
|
/// unsafe { mem::transmute(v) }
|
|
/// }
|
|
/// }
|
|
/// ```
|
|
pub trait CLike {
|
|
/// Converts a C-like enum to a `usize`.
|
|
fn to_usize(&self) -> usize;
|
|
/// Converts a `usize` to a C-like enum.
|
|
fn from_usize(usize) -> Self;
|
|
}
|
|
|
|
fn bit<E:CLike>(e: &E) -> usize {
|
|
use core::usize;
|
|
let value = e.to_usize();
|
|
assert!(value < usize::BITS,
|
|
"EnumSet only supports up to {} variants.", usize::BITS - 1);
|
|
1 << value
|
|
}
|
|
|
|
impl<E:CLike> EnumSet<E> {
|
|
/// Returns an empty `EnumSet`.
|
|
#[unstable(feature = "collections",
|
|
reason = "matches collection reform specification, waiting for dust to settle")]
|
|
pub fn new() -> EnumSet<E> {
|
|
EnumSet {bits: 0}
|
|
}
|
|
|
|
/// Returns the number of elements in the given `EnumSet`.
|
|
#[unstable(feature = "collections",
|
|
reason = "matches collection reform specification, waiting for dust to settle")]
|
|
pub fn len(&self) -> usize {
|
|
self.bits.count_ones()
|
|
}
|
|
|
|
/// Returns true if the `EnumSet` is empty.
|
|
#[unstable(feature = "collections",
|
|
reason = "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 `false` if the `EnumSet` contains any enum of the given `EnumSet`.
|
|
#[unstable(feature = "collections",
|
|
reason = "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(feature = "collections",
|
|
reason = "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(feature = "collections",
|
|
reason = "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}
|
|
}
|
|
|
|
/// Adds an enum to the `EnumSet`, and returns `true` if it wasn't there before
|
|
#[unstable(feature = "collections",
|
|
reason = "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(feature = "collections",
|
|
reason = "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
|
|
}
|
|
|
|
/// Returns `true` if an `EnumSet` contains a given enum.
|
|
#[unstable(feature = "collections",
|
|
reason = "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(feature = "collections",
|
|
reason = "matches collection reform specification, waiting for dust to settle")]
|
|
pub fn iter(&self) -> Iter<E> {
|
|
Iter::new(self.bits)
|
|
}
|
|
}
|
|
|
|
impl<E:CLike> Sub for EnumSet<E> {
|
|
type Output = EnumSet<E>;
|
|
|
|
fn sub(self, e: EnumSet<E>) -> EnumSet<E> {
|
|
EnumSet {bits: self.bits & !e.bits}
|
|
}
|
|
}
|
|
|
|
impl<E:CLike> BitOr for EnumSet<E> {
|
|
type Output = EnumSet<E>;
|
|
|
|
fn bitor(self, e: EnumSet<E>) -> EnumSet<E> {
|
|
EnumSet {bits: self.bits | e.bits}
|
|
}
|
|
}
|
|
|
|
impl<E:CLike> BitAnd for EnumSet<E> {
|
|
type Output = EnumSet<E>;
|
|
|
|
fn bitand(self, e: EnumSet<E>) -> EnumSet<E> {
|
|
EnumSet {bits: self.bits & e.bits}
|
|
}
|
|
}
|
|
|
|
impl<E:CLike> BitXor for EnumSet<E> {
|
|
type Output = EnumSet<E>;
|
|
|
|
fn bitxor(self, e: EnumSet<E>) -> EnumSet<E> {
|
|
EnumSet {bits: self.bits ^ e.bits}
|
|
}
|
|
}
|
|
|
|
/// An iterator over an EnumSet
|
|
pub struct Iter<E> {
|
|
index: usize,
|
|
bits: usize,
|
|
}
|
|
|
|
// FIXME(#19839) Remove in favor of `#[derive(Clone)]`
|
|
impl<E> Clone for Iter<E> {
|
|
fn clone(&self) -> Iter<E> {
|
|
Iter {
|
|
index: self.index,
|
|
bits: self.bits,
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<E:CLike> Iter<E> {
|
|
fn new(bits: usize) -> Iter<E> {
|
|
Iter { index: 0, bits: bits }
|
|
}
|
|
}
|
|
|
|
impl<E:CLike> Iterator for Iter<E> {
|
|
type Item = 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_usize(self.index);
|
|
self.index += 1;
|
|
self.bits >>= 1;
|
|
Some(elem)
|
|
}
|
|
|
|
fn size_hint(&self) -> (usize, Option<usize>) {
|
|
let exact = self.bits.count_ones();
|
|
(exact, Some(exact))
|
|
}
|
|
}
|
|
|
|
impl<E:CLike> FromIterator<E> for EnumSet<E> {
|
|
fn from_iter<I: IntoIterator<Item=E>>(iter: I) -> EnumSet<E> {
|
|
let mut ret = EnumSet::new();
|
|
ret.extend(iter);
|
|
ret
|
|
}
|
|
}
|
|
|
|
#[stable(feature = "rust1", since = "1.0.0")]
|
|
impl<'a, E> IntoIterator for &'a EnumSet<E> where E: CLike {
|
|
type Item = E;
|
|
type IntoIter = Iter<E>;
|
|
|
|
fn into_iter(self) -> Iter<E> {
|
|
self.iter()
|
|
}
|
|
}
|
|
|
|
impl<E:CLike> Extend<E> for EnumSet<E> {
|
|
fn extend<I: IntoIterator<Item=E>>(&mut self, iter: I) {
|
|
for element in iter {
|
|
self.insert(element);
|
|
}
|
|
}
|
|
}
|
|
|
|
#[cfg(test)]
|
|
mod test {
|
|
use self::Foo::*;
|
|
use prelude::*;
|
|
use core::mem;
|
|
|
|
use super::{EnumSet, CLike};
|
|
|
|
#[derive(Copy, PartialEq, Debug)]
|
|
#[repr(usize)]
|
|
enum Foo {
|
|
A, B, C
|
|
}
|
|
|
|
impl CLike for Foo {
|
|
fn to_usize(&self) -> usize {
|
|
*self as usize
|
|
}
|
|
|
|
fn from_usize(v: usize) -> 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!(format!("{:?}", e) == "EnumSet {}");
|
|
e.insert(A);
|
|
assert!(format!("{:?}", e) == "EnumSet {A}");
|
|
e.insert(C);
|
|
assert!(format!("{:?}", e) == "EnumSet {A, C}");
|
|
}
|
|
|
|
#[test]
|
|
fn test_len() {
|
|
let mut e = EnumSet::new();
|
|
assert_eq!(e.len(), 0);
|
|
e.insert(A);
|
|
e.insert(B);
|
|
e.insert(C);
|
|
assert_eq!(e.len(), 3);
|
|
e.remove(&A);
|
|
assert_eq!(e.len(), 2);
|
|
e.clear();
|
|
assert_eq!(e.len(), 0);
|
|
}
|
|
|
|
///////////////////////////////////////////////////////////////////////////
|
|
// 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::Vec<Foo> = e1.iter().collect();
|
|
assert!(elems.is_empty());
|
|
|
|
e1.insert(A);
|
|
let elems: ::vec::Vec<_> = e1.iter().collect();
|
|
assert_eq!(vec![A], elems);
|
|
|
|
e1.insert(C);
|
|
let elems: ::vec::Vec<_> = e1.iter().collect();
|
|
assert_eq!(vec![A,C], elems);
|
|
|
|
e1.insert(C);
|
|
let elems: ::vec::Vec<_> = e1.iter().collect();
|
|
assert_eq!(vec![A,C], elems);
|
|
|
|
e1.insert(B);
|
|
let elems: ::vec::Vec<_> = 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: ::vec::Vec<_> = e_union.iter().collect();
|
|
assert_eq!(vec![A,B,C], elems);
|
|
|
|
let e_intersection = e1 & e2;
|
|
let elems: ::vec::Vec<_> = e_intersection.iter().collect();
|
|
assert_eq!(vec![C], elems);
|
|
|
|
// Another way to express intersection
|
|
let e_intersection = e1 - (e1 - e2);
|
|
let elems: ::vec::Vec<_> = e_intersection.iter().collect();
|
|
assert_eq!(vec![C], elems);
|
|
|
|
let e_subtract = e1 - e2;
|
|
let elems: ::vec::Vec<_> = e_subtract.iter().collect();
|
|
assert_eq!(vec![A], elems);
|
|
|
|
// Bitwise XOR of two sets, aka symmetric difference
|
|
let e_symmetric_diff = e1 ^ e2;
|
|
let elems: ::vec::Vec<_> = e_symmetric_diff.iter().collect();
|
|
assert_eq!(vec![A,B], elems);
|
|
|
|
// Another way to express symmetric difference
|
|
let e_symmetric_diff = (e1 - e2) | (e2 - e1);
|
|
let elems: ::vec::Vec<_> = e_symmetric_diff.iter().collect();
|
|
assert_eq!(vec![A,B], elems);
|
|
|
|
// Yet another way to express symmetric difference
|
|
let e_symmetric_diff = (e1 | e2) - (e1 & e2);
|
|
let elems: ::vec::Vec<_> = e_symmetric_diff.iter().collect();
|
|
assert_eq!(vec![A,B], elems);
|
|
}
|
|
|
|
#[test]
|
|
#[should_fail]
|
|
fn test_overflow() {
|
|
#[allow(dead_code)]
|
|
#[derive(Copy)]
|
|
#[repr(usize)]
|
|
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_usize(&self) -> usize {
|
|
*self as usize
|
|
}
|
|
|
|
fn from_usize(v: usize) -> Bar {
|
|
unsafe { mem::transmute(v) }
|
|
}
|
|
}
|
|
let mut set = EnumSet::new();
|
|
set.insert(Bar::V64);
|
|
}
|
|
}
|