charon_lib/ids/
vector.rs

1//! A vector with custom index types.
2//!
3//! This data-structure is mostly meant to be used with the index types defined
4//! with [`crate::generate_index_type!`]: by using custom index types, we
5//! leverage the type checker to prevent us from mixing them.
6//!
7//! Note that this data structure is implemented by using persistent vectors.
8//! This makes the clone operation almost a no-op.
9
10use index_vec::{Idx, IdxSliceIndex, IndexVec};
11use serde::{Deserialize, Serialize, Serializer};
12use std::{
13    iter::{FromIterator, IntoIterator},
14    mem,
15    ops::{ControlFlow, Deref, Index, IndexMut},
16};
17
18use derive_generic_visitor::*;
19
20/// Indexed vector.
21/// To prevent accidental id reuse, the vector supports reserving a slot to be filled later.
22#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
23pub struct Vector<I, T>
24where
25    I: Idx,
26{
27    vector: IndexVec<I, Option<T>>,
28    /// The number of non-`None` elements.
29    elem_count: usize,
30}
31
32impl<I: std::fmt::Debug, T: std::fmt::Debug> std::fmt::Debug for Vector<I, T>
33where
34    I: Idx,
35{
36    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
37        <IndexVec<_, _> as std::fmt::Debug>::fmt(&self.vector, f)
38    }
39}
40
41pub struct ReservedSlot<I: Idx>(I);
42
43impl<I, T> Vector<I, T>
44where
45    I: Idx,
46{
47    pub fn new() -> Self {
48        Vector {
49            vector: IndexVec::new(),
50            elem_count: 0,
51        }
52    }
53
54    pub fn with_capacity(capacity: usize) -> Self {
55        Vector {
56            vector: IndexVec::with_capacity(capacity),
57            elem_count: 0,
58        }
59    }
60
61    pub fn get(&self, i: I) -> Option<&T> {
62        self.vector.get(i).map(Option::as_ref).flatten()
63    }
64
65    pub fn get_mut(&mut self, i: I) -> Option<&mut T> {
66        self.vector.get_mut(i).map(Option::as_mut).flatten()
67    }
68
69    pub fn is_empty(&self) -> bool {
70        self.elem_count == 0
71    }
72
73    /// The number of elements stored in the vector.
74    pub fn elem_count(&self) -> usize {
75        self.elem_count
76    }
77
78    /// The number of slots allocated in the vector (empty or not).
79    pub fn slot_count(&self) -> usize {
80        self.vector.len()
81    }
82
83    /// Gets the value of the next available id. Avoid if possible; use `reserve_slot` instead.
84    pub fn next_id(&self) -> I {
85        self.vector.next_idx()
86    }
87
88    /// Reserve a spot in the vector.
89    pub fn reserve_slot(&mut self) -> I {
90        // Push a `None` to ensure we don't reuse the id.
91        self.vector.push(None)
92    }
93
94    /// Fill the reserved slot.
95    pub fn set_slot(&mut self, id: I, x: T) {
96        assert!(self.vector[id].is_none());
97        self.vector[id] = Some(x);
98        self.elem_count += 1;
99    }
100
101    /// Remove the value from this slot, leaving other ids unchanged.
102    pub fn remove(&mut self, id: I) -> Option<T> {
103        if self.vector[id].is_some() {
104            self.elem_count -= 1;
105        }
106        self.vector[id].take()
107    }
108
109    /// Remove the value from this slot, shifting other ids as needed.
110    pub fn remove_and_shift_ids(&mut self, id: I) -> Option<T> {
111        if id.index() >= self.slot_count() {
112            return None;
113        }
114        if self.vector[id].is_some() {
115            self.elem_count -= 1;
116        }
117        self.vector.remove(id)
118    }
119
120    /// Remove the last slot.
121    pub fn pop(&mut self) -> Option<T> {
122        if self.vector.last().is_some() {
123            self.elem_count -= 1;
124        }
125        self.vector.pop().flatten()
126    }
127
128    pub fn push(&mut self, x: T) -> I {
129        self.elem_count += 1;
130        self.vector.push(Some(x))
131    }
132
133    pub fn push_with(&mut self, f: impl FnOnce(I) -> T) -> I {
134        let id = self.reserve_slot();
135        let x = f(id);
136        self.set_slot(id, x);
137        id
138    }
139
140    pub fn push_all<It>(&mut self, it: It) -> impl Iterator<Item = I> + use<'_, I, T, It>
141    where
142        It: IntoIterator<Item = T>,
143    {
144        it.into_iter().map(move |x| self.push(x))
145    }
146
147    pub fn extend<It>(&mut self, it: It)
148    where
149        It: IntoIterator<Item = T>,
150    {
151        self.push_all(it).for_each(|_| ())
152    }
153
154    pub fn extend_from_slice(&mut self, other: &Self)
155    where
156        T: Clone,
157    {
158        self.vector.extend_from_slice(&other.vector);
159        self.elem_count += other.elem_count;
160    }
161
162    /// Insert a value at that index, shifting all the values with equal or larger indices.
163    pub fn insert_and_shift_ids(&mut self, id: I, x: T) {
164        self.elem_count += 1;
165        self.vector.insert(id, Some(x))
166    }
167
168    /// Get a mutable reference into the ith element. If the vector is too short, extend it until
169    /// it has enough elements. If the element doesn't exist, use the provided function to
170    /// initialize it.
171    pub fn get_or_extend_and_insert(&mut self, id: I, f: impl FnOnce() -> T) -> &mut T {
172        if id.index() >= self.vector.len() {
173            self.vector.resize_with(id.index() + 1, || None);
174        }
175        self.vector[id].get_or_insert_with(f)
176    }
177
178    /// Map each entry to a new one, keeping the same ids.
179    pub fn map<U>(self, mut f: impl FnMut(T) -> U) -> Vector<I, U> {
180        Vector {
181            vector: self
182                .vector
183                .into_iter()
184                .map(|x_opt| x_opt.map(&mut f))
185                .collect(),
186            elem_count: self.elem_count,
187        }
188    }
189
190    /// Map each entry to a new one, keeping the same ids.
191    pub fn map_ref<'a, U>(&'a self, mut f: impl FnMut(&'a T) -> U) -> Vector<I, U> {
192        Vector {
193            vector: self
194                .vector
195                .iter()
196                .map(|x_opt| x_opt.as_ref().map(&mut f))
197                .collect(),
198            elem_count: self.elem_count,
199        }
200    }
201
202    /// Map each entry to a new one, keeping the same ids.
203    pub fn map_ref_mut<'a, U>(&'a mut self, mut f: impl FnMut(&'a mut T) -> U) -> Vector<I, U> {
204        Vector {
205            vector: self
206                .vector
207                .iter_mut()
208                .map(|x_opt| x_opt.as_mut().map(&mut f))
209                .collect(),
210            elem_count: self.elem_count,
211        }
212    }
213
214    /// Map each entry to a new one, keeping the same ids.
215    pub fn map_indexed<U>(self, mut f: impl FnMut(I, T) -> U) -> Vector<I, U> {
216        Vector {
217            vector: self
218                .vector
219                .into_iter_enumerated()
220                .map(|(i, x_opt)| x_opt.map(|x| f(i, x)))
221                .collect(),
222            elem_count: self.elem_count,
223        }
224    }
225
226    /// Map each entry to a new one, keeping the same ids.
227    pub fn map_ref_indexed<'a, U>(&'a self, mut f: impl FnMut(I, &'a T) -> U) -> Vector<I, U> {
228        Vector {
229            vector: self
230                .vector
231                .iter_enumerated()
232                .map(|(i, x_opt)| x_opt.as_ref().map(|x| f(i, x)))
233                .collect(),
234            elem_count: self.elem_count,
235        }
236    }
237
238    /// Map each entry to a new one, keeping the same ids. Includes empty slots.
239    pub fn map_opt<U>(self, f: impl FnMut(Option<T>) -> Option<U>) -> Vector<I, U> {
240        Vector {
241            vector: self.vector.into_iter().map(f).collect(),
242            elem_count: self.elem_count,
243        }
244    }
245
246    /// Map each entry to a new one, keeping the same ids. Includes empty slots.
247    pub fn map_ref_opt<'a, U>(
248        &'a self,
249        mut f: impl FnMut(Option<&'a T>) -> Option<U>,
250    ) -> Vector<I, U> {
251        let mut ret = Vector {
252            vector: self.vector.iter().map(|x_opt| f(x_opt.as_ref())).collect(),
253            elem_count: self.elem_count,
254        };
255        ret.elem_count = ret.iter().count();
256        ret
257    }
258
259    /// Iter over the nonempty slots.
260    pub fn iter(&self) -> impl Iterator<Item = &T> + DoubleEndedIterator + Clone {
261        self.vector.iter().filter_map(|opt| opt.as_ref())
262    }
263
264    pub fn iter_mut(&mut self) -> impl Iterator<Item = &mut T> + DoubleEndedIterator {
265        self.vector.iter_mut().filter_map(|opt| opt.as_mut())
266    }
267
268    pub fn iter_indexed(&self) -> impl Iterator<Item = (I, &T)> {
269        self.vector
270            .iter_enumerated()
271            .flat_map(|(i, opt)| Some((i, opt.as_ref()?)))
272    }
273
274    pub fn iter_mut_indexed(&mut self) -> impl Iterator<Item = (I, &mut T)> {
275        self.vector
276            .iter_mut_enumerated()
277            .flat_map(|(i, opt)| Some((i, opt.as_mut()?)))
278    }
279
280    pub fn into_iter_indexed(self) -> impl Iterator<Item = (I, T)> {
281        self.vector
282            .into_iter_enumerated()
283            .flat_map(|(i, opt)| Some((i, opt?)))
284    }
285
286    pub fn iter_indexed_values(&self) -> impl Iterator<Item = (I, &T)> {
287        self.iter_indexed()
288    }
289
290    pub fn into_iter_indexed_values(self) -> impl Iterator<Item = (I, T)> {
291        self.into_iter_indexed()
292    }
293
294    /// Iterate over all slots, even empty ones.
295    pub fn iter_all_slots(&self) -> impl Iterator<Item = &Option<T>> {
296        self.vector.iter()
297    }
298
299    pub fn iter_indexed_all_slots(&self) -> impl Iterator<Item = (I, &Option<T>)> {
300        self.vector.iter_enumerated()
301    }
302
303    pub fn iter_indices(&self) -> impl Iterator<Item = I> + '_ {
304        // Reuse `iter_indexed` to filter only the filled indices.
305        self.iter_indexed().map(|(id, _)| id)
306    }
307
308    pub fn all_indices(&self) -> impl Iterator<Item = I> + use<I, T> {
309        self.vector.indices()
310    }
311
312    /// Remove matching items and return and iterator over the removed items. This is lazy: items
313    /// are only removed as the iterator is consumed.
314    pub fn extract<'a, F: FnMut(&mut T) -> bool>(
315        &'a mut self,
316        mut f: F,
317    ) -> impl Iterator<Item = (I, T)> + use<'a, I, T, F> {
318        let elem_count = &mut self.elem_count;
319        self.vector
320            .iter_mut_enumerated()
321            .filter_map(move |(i, opt)| {
322                if f(opt.as_mut()?) {
323                    *elem_count -= 1;
324                    let elem = mem::replace(opt, None)?;
325                    Some((i, elem))
326                } else {
327                    None
328                }
329            })
330    }
331
332    /// Remove the elements that don't match the predicate.
333    pub fn retain(&mut self, mut f: impl FnMut(&mut T) -> bool) {
334        self.extract(|x| !f(x)).for_each(drop);
335    }
336
337    /// Like `Vec::clear`.
338    pub fn clear(&mut self) {
339        self.vector.clear();
340        self.elem_count = 0;
341    }
342    /// Like `Vec::truncate`.
343    pub fn truncate(&mut self, at: usize) {
344        self.vector.truncate(at);
345        self.elem_count = self.iter().count();
346    }
347    /// Like `Vec::split_off`.
348    pub fn split_off(&mut self, at: usize) -> Self {
349        let mut ret = Self {
350            vector: self.vector.split_off(I::from_usize(at)),
351            elem_count: 0,
352        };
353        self.elem_count = self.iter().count();
354        ret.elem_count = ret.iter().count();
355        ret
356    }
357}
358
359impl<I: Idx, T> Default for Vector<I, T> {
360    fn default() -> Self {
361        Self::new()
362    }
363}
364
365impl<I: Idx> Deref for ReservedSlot<I> {
366    type Target = I;
367    fn deref(&self) -> &Self::Target {
368        &self.0
369    }
370}
371
372impl<I, R, T> Index<R> for Vector<I, T>
373where
374    I: Idx,
375    R: IdxSliceIndex<I, Option<T>, Output = Option<T>>,
376{
377    type Output = T;
378    fn index(&self, index: R) -> &Self::Output {
379        self.vector[index].as_ref().unwrap()
380    }
381}
382
383impl<I, R, T> IndexMut<R> for Vector<I, T>
384where
385    I: Idx,
386    R: IdxSliceIndex<I, Option<T>, Output = Option<T>>,
387{
388    fn index_mut(&mut self, index: R) -> &mut Self::Output {
389        self.vector[index].as_mut().unwrap()
390    }
391}
392
393impl<'a, I, T> IntoIterator for &'a Vector<I, T>
394where
395    I: Idx,
396{
397    type Item = &'a T;
398    type IntoIter = impl Iterator<Item = &'a T>;
399
400    fn into_iter(self) -> Self::IntoIter {
401        self.vector.iter().flat_map(|opt| opt.as_ref())
402    }
403}
404
405impl<'a, I, T> IntoIterator for &'a mut Vector<I, T>
406where
407    I: Idx,
408{
409    type Item = &'a mut T;
410    type IntoIter = impl Iterator<Item = &'a mut T>;
411
412    fn into_iter(self) -> Self::IntoIter {
413        self.vector.iter_mut().flat_map(|opt| opt.as_mut())
414    }
415}
416
417impl<I, T> IntoIterator for Vector<I, T>
418where
419    I: Idx,
420{
421    type Item = T;
422    type IntoIter = impl Iterator<Item = T>;
423
424    fn into_iter(self) -> Self::IntoIter {
425        self.vector.into_iter().flat_map(|opt| opt)
426    }
427}
428
429// FIXME: this impl is a footgun
430impl<I, T> FromIterator<T> for Vector<I, T>
431where
432    I: Idx,
433{
434    #[inline]
435    fn from_iter<It: IntoIterator<Item = T>>(iter: It) -> Vector<I, T> {
436        let mut elem_count = 0;
437        let vector = IndexVec::from_iter(iter.into_iter().inspect(|_| elem_count += 1).map(Some));
438        Vector { vector, elem_count }
439    }
440}
441
442// FIXME: this impl is a footgun
443impl<I, T> From<Vec<T>> for Vector<I, T>
444where
445    I: Idx,
446{
447    fn from(v: Vec<T>) -> Self {
448        v.into_iter().collect()
449    }
450}
451
452// FIXME: this impl is a footgun
453impl<I, T, const N: usize> From<[T; N]> for Vector<I, T>
454where
455    I: Idx,
456{
457    fn from(v: [T; N]) -> Self {
458        v.into_iter().collect()
459    }
460}
461
462impl<I: Idx, T: Serialize> Serialize for Vector<I, T> {
463    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
464    where
465        S: Serializer,
466    {
467        self.vector.serialize(serializer)
468    }
469}
470
471impl<'de, I: Idx, T: Deserialize<'de>> Deserialize<'de> for Vector<I, T> {
472    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
473    where
474        D: serde::Deserializer<'de>,
475    {
476        let mut ret = Self {
477            vector: Deserialize::deserialize(deserializer)?,
478            elem_count: 0,
479        };
480        ret.elem_count = ret.iter().count();
481        Ok(ret)
482    }
483}
484
485impl<'s, I: Idx, T, V: Visit<'s, T>> Drive<'s, V> for Vector<I, T> {
486    fn drive_inner(&'s self, v: &mut V) -> ControlFlow<V::Break> {
487        for x in self {
488            v.visit(x)?;
489        }
490        Continue(())
491    }
492}
493impl<'s, I: Idx, T, V: VisitMut<'s, T>> DriveMut<'s, V> for Vector<I, T> {
494    fn drive_inner_mut(&'s mut self, v: &mut V) -> ControlFlow<V::Break> {
495        for x in self {
496            v.visit(x)?;
497        }
498        Continue(())
499    }
500}
charon_lib/ids/vector.rs

charon_lib/ids/
vector.rs
