1 #[cfg(feature = "rustc_serialize")]
2 use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
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;
21 fn increment_by(&mut self, amount: usize) {
22 *self = self.plus(amount);
26 fn plus(self, amount: usize) -> Self {
27 Self::new(self.index() + amount)
33 fn new(idx: usize) -> Self {
37 fn index(self) -> usize {
44 fn new(idx: usize) -> Self {
45 assert!(idx <= u32::MAX as usize);
49 fn index(self) -> usize {
54 #[derive(Clone, PartialEq, Eq, Hash)]
55 pub struct IndexVec<I: Idx, T> {
57 _marker: PhantomData<fn(&I)>,
60 // Whether `IndexVec` is `Send` depends only on the data,
61 // not the phantom data.
62 unsafe impl<I: Idx, T> Send for IndexVec<I, T> where T: Send {}
64 #[cfg(feature = "rustc_serialize")]
65 impl<S: Encoder, I: Idx, T: Encodable<S>> Encodable<S> for IndexVec<I, T> {
66 fn encode(&self, s: &mut S) {
67 Encodable::encode(&self.raw, s);
71 #[cfg(feature = "rustc_serialize")]
72 impl<D: Decoder, I: Idx, T: Decodable<D>> Decodable<D> for IndexVec<I, T> {
73 fn decode(d: &mut D) -> Self {
74 IndexVec { raw: Decodable::decode(d), _marker: PhantomData }
78 impl<I: Idx, T: fmt::Debug> fmt::Debug for IndexVec<I, T> {
79 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
80 fmt::Debug::fmt(&self.raw, fmt)
84 impl<I: Idx, T> IndexVec<I, T> {
86 pub fn new() -> Self {
87 IndexVec { raw: Vec::new(), _marker: PhantomData }
91 pub fn from_raw(raw: Vec<T>) -> Self {
92 IndexVec { raw, _marker: PhantomData }
96 pub fn with_capacity(capacity: usize) -> Self {
97 IndexVec { raw: Vec::with_capacity(capacity), _marker: PhantomData }
101 pub fn from_elem<S>(elem: T, universe: &IndexVec<I, S>) -> Self
105 IndexVec { raw: vec![elem; universe.len()], _marker: PhantomData }
109 pub fn from_elem_n(elem: T, n: usize) -> Self
113 IndexVec { raw: vec![elem; n], _marker: PhantomData }
116 /// Create an `IndexVec` with `n` elements, where the value of each
117 /// element is the result of `func(i)`. (The underlying vector will
118 /// be allocated only once, with a capacity of at least `n`.)
120 pub fn from_fn_n(func: impl FnMut(I) -> T, n: usize) -> Self {
121 let indices = (0..n).map(I::new);
122 Self::from_raw(indices.map(func).collect())
126 pub fn push(&mut self, d: T) -> I {
127 let idx = I::new(self.len());
133 pub fn pop(&mut self) -> Option<T> {
138 pub fn len(&self) -> usize {
142 /// Gives the next index that will be assigned when `push` is
145 pub fn next_index(&self) -> I {
150 pub fn is_empty(&self) -> bool {
155 pub fn into_iter(self) -> vec::IntoIter<T> {
160 pub fn into_iter_enumerated(
162 ) -> impl DoubleEndedIterator<Item = (I, T)> + ExactSizeIterator {
163 self.raw.into_iter().enumerate().map(|(n, t)| (I::new(n), t))
167 pub fn iter(&self) -> slice::Iter<'_, T> {
172 pub fn iter_enumerated(
174 ) -> impl DoubleEndedIterator<Item = (I, &T)> + ExactSizeIterator + '_ {
175 self.raw.iter().enumerate().map(|(n, t)| (I::new(n), t))
181 ) -> impl DoubleEndedIterator<Item = I> + ExactSizeIterator + Clone + 'static {
182 (0..self.len()).map(|n| I::new(n))
186 pub fn iter_mut(&mut self) -> slice::IterMut<'_, T> {
191 pub fn iter_enumerated_mut(
193 ) -> impl DoubleEndedIterator<Item = (I, &mut T)> + ExactSizeIterator + '_ {
194 self.raw.iter_mut().enumerate().map(|(n, t)| (I::new(n), t))
198 pub fn drain<'a, R: RangeBounds<usize>>(
201 ) -> impl Iterator<Item = T> + 'a {
202 self.raw.drain(range)
206 pub fn drain_enumerated<'a, R: RangeBounds<usize>>(
209 ) -> impl Iterator<Item = (I, T)> + 'a {
210 let begin = match range.start_bound() {
211 std::ops::Bound::Included(i) => *i,
212 std::ops::Bound::Excluded(i) => i.checked_add(1).unwrap(),
213 std::ops::Bound::Unbounded => 0,
215 self.raw.drain(range).enumerate().map(move |(n, t)| (I::new(begin + n), t))
219 pub fn last(&self) -> Option<I> {
220 self.len().checked_sub(1).map(I::new)
224 pub fn shrink_to_fit(&mut self) {
225 self.raw.shrink_to_fit()
229 pub fn swap(&mut self, a: I, b: I) {
230 self.raw.swap(a.index(), b.index())
234 pub fn truncate(&mut self, a: usize) {
239 pub fn get(&self, index: I) -> Option<&T> {
240 self.raw.get(index.index())
244 pub fn get_mut(&mut self, index: I) -> Option<&mut T> {
245 self.raw.get_mut(index.index())
248 /// Returns mutable references to two distinct elements, `a` and `b`.
250 /// Panics if `a == b`.
252 pub fn pick2_mut(&mut self, a: I, b: I) -> (&mut T, &mut T) {
253 let (ai, bi) = (a.index(), b.index());
257 let (c1, c2) = self.raw.split_at_mut(bi);
258 (&mut c1[ai], &mut c2[0])
260 let (c2, c1) = self.pick2_mut(b, a);
265 /// Returns mutable references to three distinct elements.
267 /// Panics if the elements are not distinct.
269 pub fn pick3_mut(&mut self, a: I, b: I, c: I) -> (&mut T, &mut T, &mut T) {
270 let (ai, bi, ci) = (a.index(), b.index(), c.index());
271 assert!(ai != bi && bi != ci && ci != ai);
272 let len = self.raw.len();
273 assert!(ai < len && bi < len && ci < len);
274 let ptr = self.raw.as_mut_ptr();
275 unsafe { (&mut *ptr.add(ai), &mut *ptr.add(bi), &mut *ptr.add(ci)) }
278 pub fn convert_index_type<Ix: Idx>(self) -> IndexVec<Ix, T> {
279 IndexVec { raw: self.raw, _marker: PhantomData }
282 /// Grows the index vector so that it contains an entry for
283 /// `elem`; if that is already true, then has no
284 /// effect. Otherwise, inserts new values as needed by invoking
287 pub fn ensure_contains_elem(&mut self, elem: I, fill_value: impl FnMut() -> T) {
288 let min_new_len = elem.index() + 1;
289 if self.len() < min_new_len {
290 self.raw.resize_with(min_new_len, fill_value);
295 pub fn resize_to_elem(&mut self, elem: I, fill_value: impl FnMut() -> T) {
296 let min_new_len = elem.index() + 1;
297 self.raw.resize_with(min_new_len, fill_value);
301 /// `IndexVec` is often used as a map, so it provides some map-like APIs.
302 impl<I: Idx, T> IndexVec<I, Option<T>> {
304 pub fn insert(&mut self, index: I, value: T) -> Option<T> {
305 self.ensure_contains_elem(index, || None);
306 self[index].replace(value)
310 pub fn get_or_insert_with(&mut self, index: I, value: impl FnOnce() -> T) -> &mut T {
311 self.ensure_contains_elem(index, || None);
312 self[index].get_or_insert_with(value)
316 pub fn remove(&mut self, index: I) -> Option<T> {
317 self.ensure_contains_elem(index, || None);
322 impl<I: Idx, T: Clone> IndexVec<I, T> {
324 pub fn resize(&mut self, new_len: usize, value: T) {
325 self.raw.resize(new_len, value)
329 impl<I: Idx, T: Ord> IndexVec<I, T> {
331 pub fn binary_search(&self, value: &T) -> Result<I, I> {
332 match self.raw.binary_search(value) {
333 Ok(i) => Ok(Idx::new(i)),
334 Err(i) => Err(Idx::new(i)),
339 impl<I: Idx, T> Index<I> for IndexVec<I, T> {
343 fn index(&self, index: I) -> &T {
344 &self.raw[index.index()]
348 impl<I: Idx, T> IndexMut<I> for IndexVec<I, T> {
350 fn index_mut(&mut self, index: I) -> &mut T {
351 &mut self.raw[index.index()]
355 impl<I: Idx, T> Default for IndexVec<I, T> {
357 fn default() -> Self {
362 impl<I: Idx, T> Extend<T> for IndexVec<I, T> {
364 fn extend<J: IntoIterator<Item = T>>(&mut self, iter: J) {
365 self.raw.extend(iter);
369 #[cfg(feature = "nightly")]
370 fn extend_one(&mut self, item: T) {
375 #[cfg(feature = "nightly")]
376 fn extend_reserve(&mut self, additional: usize) {
377 self.raw.reserve(additional);
381 impl<I: Idx, T> FromIterator<T> for IndexVec<I, T> {
383 fn from_iter<J>(iter: J) -> Self
385 J: IntoIterator<Item = T>,
387 IndexVec { raw: FromIterator::from_iter(iter), _marker: PhantomData }
391 impl<I: Idx, T> IntoIterator for IndexVec<I, T> {
393 type IntoIter = vec::IntoIter<T>;
396 fn into_iter(self) -> vec::IntoIter<T> {
401 impl<'a, I: Idx, T> IntoIterator for &'a IndexVec<I, T> {
403 type IntoIter = slice::Iter<'a, T>;
406 fn into_iter(self) -> slice::Iter<'a, T> {
411 impl<'a, I: Idx, T> IntoIterator for &'a mut IndexVec<I, T> {
412 type Item = &'a mut T;
413 type IntoIter = slice::IterMut<'a, T>;
416 fn into_iter(self) -> slice::IterMut<'a, T> {