1 use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
6 use std::iter::FromIterator;
7 use std::marker::PhantomData;
8 use std::ops::{Index, IndexMut, RangeBounds};
12 /// Represents some newtyped `usize` wrapper.
14 /// Purpose: avoid mixing indexes for different bitvector domains.
15 pub trait Idx: Copy + 'static + Eq + PartialEq + Debug + Hash {
16 fn new(idx: usize) -> Self;
18 fn index(self) -> usize;
20 fn increment_by(&mut self, amount: usize) {
21 *self = self.plus(amount);
24 fn plus(self, amount: usize) -> Self {
25 Self::new(self.index() + amount)
31 fn new(idx: usize) -> Self {
35 fn index(self) -> usize {
42 fn new(idx: usize) -> Self {
43 assert!(idx <= u32::MAX as usize);
47 fn index(self) -> usize {
52 #[derive(Clone, PartialEq, Eq, Hash)]
53 pub struct IndexVec<I: Idx, T> {
55 _marker: PhantomData<fn(&I)>,
58 // Whether `IndexVec` is `Send` depends only on the data,
59 // not the phantom data.
60 unsafe impl<I: Idx, T> Send for IndexVec<I, T> where T: Send {}
62 impl<S: Encoder, I: Idx, T: Encodable<S>> Encodable<S> for IndexVec<I, T> {
63 fn encode(&self, s: &mut S) {
64 Encodable::encode(&self.raw, s);
68 impl<D: Decoder, I: Idx, T: Decodable<D>> Decodable<D> for IndexVec<I, T> {
69 fn decode(d: &mut D) -> Self {
70 IndexVec { raw: Decodable::decode(d), _marker: PhantomData }
74 impl<I: Idx, T: fmt::Debug> fmt::Debug for IndexVec<I, T> {
75 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
76 fmt::Debug::fmt(&self.raw, fmt)
80 impl<I: Idx, T> IndexVec<I, T> {
82 pub fn new() -> Self {
83 IndexVec { raw: Vec::new(), _marker: PhantomData }
87 pub fn from_raw(raw: Vec<T>) -> Self {
88 IndexVec { raw, _marker: PhantomData }
92 pub fn with_capacity(capacity: usize) -> Self {
93 IndexVec { raw: Vec::with_capacity(capacity), _marker: PhantomData }
97 pub fn from_elem<S>(elem: T, universe: &IndexVec<I, S>) -> Self
101 IndexVec { raw: vec![elem; universe.len()], _marker: PhantomData }
105 pub fn from_elem_n(elem: T, n: usize) -> Self
109 IndexVec { raw: vec![elem; n], _marker: PhantomData }
112 /// Create an `IndexVec` with `n` elements, where the value of each
113 /// element is the result of `func(i)`. (The underlying vector will
114 /// be allocated only once, with a capacity of at least `n`.)
116 pub fn from_fn_n(func: impl FnMut(I) -> T, n: usize) -> Self {
117 let indices = (0..n).map(I::new);
118 Self::from_raw(indices.map(func).collect())
122 pub fn push(&mut self, d: T) -> I {
123 let idx = I::new(self.len());
129 pub fn pop(&mut self) -> Option<T> {
134 pub fn len(&self) -> usize {
138 /// Gives the next index that will be assigned when `push` is
141 pub fn next_index(&self) -> I {
146 pub fn is_empty(&self) -> bool {
151 pub fn into_iter(self) -> vec::IntoIter<T> {
156 pub fn into_iter_enumerated(
158 ) -> impl DoubleEndedIterator<Item = (I, T)> + ExactSizeIterator {
159 self.raw.into_iter().enumerate().map(|(n, t)| (I::new(n), t))
163 pub fn iter(&self) -> slice::Iter<'_, T> {
168 pub fn iter_enumerated(
170 ) -> impl DoubleEndedIterator<Item = (I, &T)> + ExactSizeIterator + '_ {
171 self.raw.iter().enumerate().map(|(n, t)| (I::new(n), t))
175 pub fn indices(&self) -> impl DoubleEndedIterator<Item = I> + ExactSizeIterator + 'static {
176 (0..self.len()).map(|n| I::new(n))
180 pub fn iter_mut(&mut self) -> slice::IterMut<'_, T> {
185 pub fn iter_enumerated_mut(
187 ) -> impl DoubleEndedIterator<Item = (I, &mut T)> + ExactSizeIterator + '_ {
188 self.raw.iter_mut().enumerate().map(|(n, t)| (I::new(n), t))
192 pub fn drain<'a, R: RangeBounds<usize>>(
195 ) -> impl Iterator<Item = T> + 'a {
196 self.raw.drain(range)
200 pub fn drain_enumerated<'a, R: RangeBounds<usize>>(
203 ) -> impl Iterator<Item = (I, T)> + 'a {
204 self.raw.drain(range).enumerate().map(|(n, t)| (I::new(n), t))
208 pub fn last(&self) -> Option<I> {
209 self.len().checked_sub(1).map(I::new)
213 pub fn shrink_to_fit(&mut self) {
214 self.raw.shrink_to_fit()
218 pub fn swap(&mut self, a: I, b: I) {
219 self.raw.swap(a.index(), b.index())
223 pub fn truncate(&mut self, a: usize) {
228 pub fn get(&self, index: I) -> Option<&T> {
229 self.raw.get(index.index())
233 pub fn get_mut(&mut self, index: I) -> Option<&mut T> {
234 self.raw.get_mut(index.index())
237 /// Returns mutable references to two distinct elements, `a` and `b`.
239 /// Panics if `a == b`.
241 pub fn pick2_mut(&mut self, a: I, b: I) -> (&mut T, &mut T) {
242 let (ai, bi) = (a.index(), b.index());
246 let (c1, c2) = self.raw.split_at_mut(bi);
247 (&mut c1[ai], &mut c2[0])
249 let (c2, c1) = self.pick2_mut(b, a);
254 /// Returns mutable references to three distinct elements.
256 /// Panics if the elements are not distinct.
258 pub fn pick3_mut(&mut self, a: I, b: I, c: I) -> (&mut T, &mut T, &mut T) {
259 let (ai, bi, ci) = (a.index(), b.index(), c.index());
260 assert!(ai != bi && bi != ci && ci != ai);
261 let len = self.raw.len();
262 assert!(ai < len && bi < len && ci < len);
263 let ptr = self.raw.as_mut_ptr();
264 unsafe { (&mut *ptr.add(ai), &mut *ptr.add(bi), &mut *ptr.add(ci)) }
267 pub fn convert_index_type<Ix: Idx>(self) -> IndexVec<Ix, T> {
268 IndexVec { raw: self.raw, _marker: PhantomData }
271 /// Grows the index vector so that it contains an entry for
272 /// `elem`; if that is already true, then has no
273 /// effect. Otherwise, inserts new values as needed by invoking
276 pub fn ensure_contains_elem(&mut self, elem: I, fill_value: impl FnMut() -> T) {
277 let min_new_len = elem.index() + 1;
278 if self.len() < min_new_len {
279 self.raw.resize_with(min_new_len, fill_value);
284 pub fn resize_to_elem(&mut self, elem: I, fill_value: impl FnMut() -> T) {
285 let min_new_len = elem.index() + 1;
286 self.raw.resize_with(min_new_len, fill_value);
290 /// `IndexVec` is often used as a map, so it provides some map-like APIs.
291 impl<I: Idx, T> IndexVec<I, Option<T>> {
293 pub fn insert(&mut self, index: I, value: T) -> Option<T> {
294 self.ensure_contains_elem(index, || None);
295 self[index].replace(value)
299 pub fn get_or_insert_with(&mut self, index: I, value: impl FnOnce() -> T) -> &mut T {
300 self.ensure_contains_elem(index, || None);
301 self[index].get_or_insert_with(value)
305 pub fn remove(&mut self, index: I) -> Option<T> {
306 self.ensure_contains_elem(index, || None);
311 impl<I: Idx, T: Clone> IndexVec<I, T> {
313 pub fn resize(&mut self, new_len: usize, value: T) {
314 self.raw.resize(new_len, value)
318 impl<I: Idx, T: Ord> IndexVec<I, T> {
320 pub fn binary_search(&self, value: &T) -> Result<I, I> {
321 match self.raw.binary_search(value) {
322 Ok(i) => Ok(Idx::new(i)),
323 Err(i) => Err(Idx::new(i)),
328 impl<I: Idx, T> Index<I> for IndexVec<I, T> {
332 fn index(&self, index: I) -> &T {
333 &self.raw[index.index()]
337 impl<I: Idx, T> IndexMut<I> for IndexVec<I, T> {
339 fn index_mut(&mut self, index: I) -> &mut T {
340 &mut self.raw[index.index()]
344 impl<I: Idx, T> Default for IndexVec<I, T> {
346 fn default() -> Self {
351 impl<I: Idx, T> Extend<T> for IndexVec<I, T> {
353 fn extend<J: IntoIterator<Item = T>>(&mut self, iter: J) {
354 self.raw.extend(iter);
358 fn extend_one(&mut self, item: T) {
363 fn extend_reserve(&mut self, additional: usize) {
364 self.raw.reserve(additional);
368 impl<I: Idx, T> FromIterator<T> for IndexVec<I, T> {
370 fn from_iter<J>(iter: J) -> Self
372 J: IntoIterator<Item = T>,
374 IndexVec { raw: FromIterator::from_iter(iter), _marker: PhantomData }
378 impl<I: Idx, T> IntoIterator for IndexVec<I, T> {
380 type IntoIter = vec::IntoIter<T>;
383 fn into_iter(self) -> vec::IntoIter<T> {
388 impl<'a, I: Idx, T> IntoIterator for &'a IndexVec<I, T> {
390 type IntoIter = slice::Iter<'a, T>;
393 fn into_iter(self) -> slice::Iter<'a, T> {
398 impl<'a, I: Idx, T> IntoIterator for &'a mut IndexVec<I, T> {
399 type Item = &'a mut T;
400 type IntoIter = slice::IterMut<'a, T>;
403 fn into_iter(self) -> slice::IterMut<'a, T> {