1 #[cfg(feature = "rustc_serialize")]
2 use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
7 use std::iter::FromIterator;
8 use std::marker::PhantomData;
9 use std::ops::{Index, IndexMut, RangeBounds};
13 /// Represents some newtyped `usize` wrapper.
15 /// Purpose: avoid mixing indexes for different bitvector domains.
16 pub trait Idx: Copy + 'static + Eq + PartialEq + Debug + Hash {
17 fn new(idx: usize) -> Self;
19 fn index(self) -> usize;
22 fn increment_by(&mut self, amount: usize) {
23 *self = self.plus(amount);
27 fn plus(self, amount: usize) -> Self {
28 Self::new(self.index() + amount)
34 fn new(idx: usize) -> Self {
38 fn index(self) -> usize {
45 fn new(idx: usize) -> Self {
46 assert!(idx <= u32::MAX as usize);
50 fn index(self) -> usize {
55 #[derive(Clone, PartialEq, Eq, Hash)]
56 pub struct IndexVec<I: Idx, T> {
58 _marker: PhantomData<fn(&I)>,
61 // Whether `IndexVec` is `Send` depends only on the data,
62 // not the phantom data.
63 unsafe impl<I: Idx, T> Send for IndexVec<I, T> where T: Send {}
65 #[cfg(feature = "rustc_serialize")]
66 impl<S: Encoder, I: Idx, T: Encodable<S>> Encodable<S> for IndexVec<I, T> {
67 fn encode(&self, s: &mut S) {
68 Encodable::encode(&self.raw, s);
72 #[cfg(feature = "rustc_serialize")]
73 impl<D: Decoder, I: Idx, T: Decodable<D>> Decodable<D> for IndexVec<I, T> {
74 fn decode(d: &mut D) -> Self {
75 IndexVec { raw: Decodable::decode(d), _marker: PhantomData }
79 impl<I: Idx, T: fmt::Debug> fmt::Debug for IndexVec<I, T> {
80 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
81 fmt::Debug::fmt(&self.raw, fmt)
85 impl<I: Idx, T> IndexVec<I, T> {
87 pub fn new() -> Self {
88 IndexVec { raw: Vec::new(), _marker: PhantomData }
92 pub fn from_raw(raw: Vec<T>) -> Self {
93 IndexVec { raw, _marker: PhantomData }
97 pub fn with_capacity(capacity: usize) -> Self {
98 IndexVec { raw: Vec::with_capacity(capacity), _marker: PhantomData }
102 pub fn from_elem<S>(elem: T, universe: &IndexVec<I, S>) -> Self
106 IndexVec { raw: vec![elem; universe.len()], _marker: PhantomData }
110 pub fn from_elem_n(elem: T, n: usize) -> Self
114 IndexVec { raw: vec![elem; n], _marker: PhantomData }
117 /// Create an `IndexVec` with `n` elements, where the value of each
118 /// element is the result of `func(i)`. (The underlying vector will
119 /// be allocated only once, with a capacity of at least `n`.)
121 pub fn from_fn_n(func: impl FnMut(I) -> T, n: usize) -> Self {
122 let indices = (0..n).map(I::new);
123 Self::from_raw(indices.map(func).collect())
127 pub fn push(&mut self, d: T) -> I {
128 let idx = I::new(self.len());
134 pub fn pop(&mut self) -> Option<T> {
139 pub fn len(&self) -> usize {
143 /// Gives the next index that will be assigned when `push` is
146 pub fn next_index(&self) -> I {
151 pub fn is_empty(&self) -> bool {
156 pub fn into_iter(self) -> vec::IntoIter<T> {
161 pub fn into_iter_enumerated(
163 ) -> impl DoubleEndedIterator<Item = (I, T)> + ExactSizeIterator {
164 self.raw.into_iter().enumerate().map(|(n, t)| (I::new(n), t))
168 pub fn iter(&self) -> slice::Iter<'_, T> {
173 pub fn iter_enumerated(
175 ) -> impl DoubleEndedIterator<Item = (I, &T)> + ExactSizeIterator + '_ {
176 self.raw.iter().enumerate().map(|(n, t)| (I::new(n), t))
182 ) -> impl DoubleEndedIterator<Item = I> + ExactSizeIterator + Clone + 'static {
183 (0..self.len()).map(|n| I::new(n))
187 pub fn iter_mut(&mut self) -> slice::IterMut<'_, T> {
192 pub fn iter_enumerated_mut(
194 ) -> impl DoubleEndedIterator<Item = (I, &mut T)> + ExactSizeIterator + '_ {
195 self.raw.iter_mut().enumerate().map(|(n, t)| (I::new(n), t))
199 pub fn drain<'a, R: RangeBounds<usize>>(
202 ) -> impl Iterator<Item = T> + 'a {
203 self.raw.drain(range)
207 pub fn drain_enumerated<'a, R: RangeBounds<usize>>(
210 ) -> impl Iterator<Item = (I, T)> + 'a {
211 self.raw.drain(range).enumerate().map(|(n, t)| (I::new(n), t))
215 pub fn last(&self) -> Option<I> {
216 self.len().checked_sub(1).map(I::new)
220 pub fn shrink_to_fit(&mut self) {
221 self.raw.shrink_to_fit()
225 pub fn swap(&mut self, a: I, b: I) {
226 self.raw.swap(a.index(), b.index())
230 pub fn truncate(&mut self, a: usize) {
235 pub fn get(&self, index: I) -> Option<&T> {
236 self.raw.get(index.index())
240 pub fn get_mut(&mut self, index: I) -> Option<&mut T> {
241 self.raw.get_mut(index.index())
244 /// Returns mutable references to two distinct elements, `a` and `b`.
246 /// Panics if `a == b`.
248 pub fn pick2_mut(&mut self, a: I, b: I) -> (&mut T, &mut T) {
249 let (ai, bi) = (a.index(), b.index());
253 let (c1, c2) = self.raw.split_at_mut(bi);
254 (&mut c1[ai], &mut c2[0])
256 let (c2, c1) = self.pick2_mut(b, a);
261 /// Returns mutable references to three distinct elements.
263 /// Panics if the elements are not distinct.
265 pub fn pick3_mut(&mut self, a: I, b: I, c: I) -> (&mut T, &mut T, &mut T) {
266 let (ai, bi, ci) = (a.index(), b.index(), c.index());
267 assert!(ai != bi && bi != ci && ci != ai);
268 let len = self.raw.len();
269 assert!(ai < len && bi < len && ci < len);
270 let ptr = self.raw.as_mut_ptr();
271 unsafe { (&mut *ptr.add(ai), &mut *ptr.add(bi), &mut *ptr.add(ci)) }
274 pub fn convert_index_type<Ix: Idx>(self) -> IndexVec<Ix, T> {
275 IndexVec { raw: self.raw, _marker: PhantomData }
278 /// Grows the index vector so that it contains an entry for
279 /// `elem`; if that is already true, then has no
280 /// effect. Otherwise, inserts new values as needed by invoking
283 pub fn ensure_contains_elem(&mut self, elem: I, fill_value: impl FnMut() -> T) {
284 let min_new_len = elem.index() + 1;
285 if self.len() < min_new_len {
286 self.raw.resize_with(min_new_len, fill_value);
291 pub fn resize_to_elem(&mut self, elem: I, fill_value: impl FnMut() -> T) {
292 let min_new_len = elem.index() + 1;
293 self.raw.resize_with(min_new_len, fill_value);
297 /// `IndexVec` is often used as a map, so it provides some map-like APIs.
298 impl<I: Idx, T> IndexVec<I, Option<T>> {
300 pub fn insert(&mut self, index: I, value: T) -> Option<T> {
301 self.ensure_contains_elem(index, || None);
302 self[index].replace(value)
306 pub fn get_or_insert_with(&mut self, index: I, value: impl FnOnce() -> T) -> &mut T {
307 self.ensure_contains_elem(index, || None);
308 self[index].get_or_insert_with(value)
312 pub fn remove(&mut self, index: I) -> Option<T> {
313 self.ensure_contains_elem(index, || None);
318 impl<I: Idx, T: Clone> IndexVec<I, T> {
320 pub fn resize(&mut self, new_len: usize, value: T) {
321 self.raw.resize(new_len, value)
325 impl<I: Idx, T: Ord> IndexVec<I, T> {
327 pub fn binary_search(&self, value: &T) -> Result<I, I> {
328 match self.raw.binary_search(value) {
329 Ok(i) => Ok(Idx::new(i)),
330 Err(i) => Err(Idx::new(i)),
335 impl<I: Idx, T> Index<I> for IndexVec<I, T> {
339 fn index(&self, index: I) -> &T {
340 &self.raw[index.index()]
344 impl<I: Idx, T> IndexMut<I> for IndexVec<I, T> {
346 fn index_mut(&mut self, index: I) -> &mut T {
347 &mut self.raw[index.index()]
351 impl<I: Idx, T> Default for IndexVec<I, T> {
353 fn default() -> Self {
358 impl<I: Idx, T> Extend<T> for IndexVec<I, T> {
360 fn extend<J: IntoIterator<Item = T>>(&mut self, iter: J) {
361 self.raw.extend(iter);
365 #[cfg(feature = "nightly")]
366 fn extend_one(&mut self, item: T) {
371 #[cfg(feature = "nightly")]
372 fn extend_reserve(&mut self, additional: usize) {
373 self.raw.reserve(additional);
377 impl<I: Idx, T> FromIterator<T> for IndexVec<I, T> {
379 fn from_iter<J>(iter: J) -> Self
381 J: IntoIterator<Item = T>,
383 IndexVec { raw: FromIterator::from_iter(iter), _marker: PhantomData }
387 impl<I: Idx, T> IntoIterator for IndexVec<I, T> {
389 type IntoIter = vec::IntoIter<T>;
392 fn into_iter(self) -> vec::IntoIter<T> {
397 impl<'a, I: Idx, T> IntoIterator for &'a IndexVec<I, T> {
399 type IntoIter = slice::Iter<'a, T>;
402 fn into_iter(self) -> slice::Iter<'a, T> {
407 impl<'a, I: Idx, T> IntoIterator for &'a mut IndexVec<I, T> {
408 type Item = &'a mut T;
409 type IntoIter = slice::IterMut<'a, T>;
412 fn into_iter(self) -> slice::IterMut<'a, T> {