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_ref_indexed<'a, U>(&'a self, mut f: impl FnMut(I, &'a T) -> U) -> Vector<I, U> {
216        Vector {
217            vector: self
218                .vector
219                .iter_enumerated()
220                .map(|(i, x_opt)| x_opt.as_ref().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. Includes empty slots.
227    pub fn map_opt<U>(self, f: impl FnMut(Option<T>) -> Option<U>) -> Vector<I, U> {
228        Vector {
229            vector: self.vector.into_iter().map(f).collect(),
230            elem_count: self.elem_count,
231        }
232    }
233
234    /// Map each entry to a new one, keeping the same ids. Includes empty slots.
235    pub fn map_ref_opt<'a, U>(
236        &'a self,
237        mut f: impl FnMut(Option<&'a T>) -> Option<U>,
238    ) -> Vector<I, U> {
239        let mut ret = Vector {
240            vector: self.vector.iter().map(|x_opt| f(x_opt.as_ref())).collect(),
241            elem_count: self.elem_count,
242        };
243        ret.elem_count = ret.iter().count();
244        ret
245    }
246
247    /// Iter over the nonempty slots.
248    pub fn iter(&self) -> impl Iterator<Item = &T> + DoubleEndedIterator + Clone {
249        self.vector.iter().filter_map(|opt| opt.as_ref())
250    }
251
252    pub fn iter_mut(&mut self) -> impl Iterator<Item = &mut T> + DoubleEndedIterator {
253        self.vector.iter_mut().filter_map(|opt| opt.as_mut())
254    }
255
256    pub fn iter_indexed(&self) -> impl Iterator<Item = (I, &T)> {
257        self.vector
258            .iter_enumerated()
259            .flat_map(|(i, opt)| Some((i, opt.as_ref()?)))
260    }
261
262    pub fn iter_mut_indexed(&mut self) -> impl Iterator<Item = (I, &mut T)> {
263        self.vector
264            .iter_mut_enumerated()
265            .flat_map(|(i, opt)| Some((i, opt.as_mut()?)))
266    }
267
268    pub fn into_iter_indexed(self) -> impl Iterator<Item = (I, T)> {
269        self.vector
270            .into_iter_enumerated()
271            .flat_map(|(i, opt)| Some((i, opt?)))
272    }
273
274    pub fn iter_indexed_values(&self) -> impl Iterator<Item = (I, &T)> {
275        self.iter_indexed()
276    }
277
278    pub fn into_iter_indexed_values(self) -> impl Iterator<Item = (I, T)> {
279        self.into_iter_indexed()
280    }
281
282    /// Iterate over all slots, even empty ones.
283    pub fn iter_all_slots(&self) -> impl Iterator<Item = &Option<T>> {
284        self.vector.iter()
285    }
286
287    pub fn iter_indexed_all_slots(&self) -> impl Iterator<Item = (I, &Option<T>)> {
288        self.vector.iter_enumerated()
289    }
290
291    pub fn iter_indices(&self) -> impl Iterator<Item = I> + '_ {
292        // Reuse `iter_indexed` to filter only the filled indices.
293        self.iter_indexed().map(|(id, _)| id)
294    }
295
296    pub fn all_indices(&self) -> impl Iterator<Item = I> + use<I, T> {
297        self.vector.indices()
298    }
299
300    /// Remove matching items and return and iterator over the removed items. This is lazy: items
301    /// are only removed as the iterator is consumed.
302    pub fn extract<'a, F: FnMut(&mut T) -> bool>(
303        &'a mut self,
304        mut f: F,
305    ) -> impl Iterator<Item = (I, T)> + use<'a, I, T, F> {
306        let elem_count = &mut self.elem_count;
307        self.vector
308            .iter_mut_enumerated()
309            .filter_map(move |(i, opt)| {
310                if f(opt.as_mut()?) {
311                    *elem_count -= 1;
312                    let elem = mem::replace(opt, None)?;
313                    Some((i, elem))
314                } else {
315                    None
316                }
317            })
318    }
319
320    /// Remove the elements that don't match the predicate.
321    pub fn retain(&mut self, mut f: impl FnMut(&mut T) -> bool) {
322        self.extract(|x| !f(x)).for_each(drop);
323    }
324
325    /// Like `Vec::split_off`.
326    pub fn split_off(&mut self, at: usize) -> Self {
327        let mut ret = Self {
328            vector: self.vector.split_off(I::from_usize(at)),
329            elem_count: 0,
330        };
331        self.elem_count = self.iter().count();
332        ret.elem_count = ret.iter().count();
333        ret
334    }
335}
336
337impl<I: Idx, T> Default for Vector<I, T> {
338    fn default() -> Self {
339        Self::new()
340    }
341}
342
343impl<I: Idx> Deref for ReservedSlot<I> {
344    type Target = I;
345    fn deref(&self) -> &Self::Target {
346        &self.0
347    }
348}
349
350impl<I, R, T> Index<R> for Vector<I, T>
351where
352    I: Idx,
353    R: IdxSliceIndex<I, Option<T>, Output = Option<T>>,
354{
355    type Output = T;
356    fn index(&self, index: R) -> &Self::Output {
357        self.vector[index].as_ref().unwrap()
358    }
359}
360
361impl<I, R, T> IndexMut<R> for Vector<I, T>
362where
363    I: Idx,
364    R: IdxSliceIndex<I, Option<T>, Output = Option<T>>,
365{
366    fn index_mut(&mut self, index: R) -> &mut Self::Output {
367        self.vector[index].as_mut().unwrap()
368    }
369}
370
371impl<'a, I, T> IntoIterator for &'a Vector<I, T>
372where
373    I: Idx,
374{
375    type Item = &'a T;
376    type IntoIter = impl Iterator<Item = &'a T>;
377
378    fn into_iter(self) -> Self::IntoIter {
379        self.vector.iter().flat_map(|opt| opt.as_ref())
380    }
381}
382
383impl<'a, I, T> IntoIterator for &'a mut Vector<I, T>
384where
385    I: Idx,
386{
387    type Item = &'a mut T;
388    type IntoIter = impl Iterator<Item = &'a mut T>;
389
390    fn into_iter(self) -> Self::IntoIter {
391        self.vector.iter_mut().flat_map(|opt| opt.as_mut())
392    }
393}
394
395impl<I, T> IntoIterator for Vector<I, T>
396where
397    I: Idx,
398{
399    type Item = T;
400    type IntoIter = impl Iterator<Item = T>;
401
402    fn into_iter(self) -> Self::IntoIter {
403        self.vector.into_iter().flat_map(|opt| opt)
404    }
405}
406
407// FIXME: this impl is a footgun
408impl<I, T> FromIterator<T> for Vector<I, T>
409where
410    I: Idx,
411{
412    #[inline]
413    fn from_iter<It: IntoIterator<Item = T>>(iter: It) -> Vector<I, T> {
414        let mut elem_count = 0;
415        let vector = IndexVec::from_iter(iter.into_iter().inspect(|_| elem_count += 1).map(Some));
416        Vector { vector, elem_count }
417    }
418}
419
420// FIXME: this impl is a footgun
421impl<I, T> From<Vec<T>> for Vector<I, T>
422where
423    I: Idx,
424{
425    fn from(v: Vec<T>) -> Self {
426        v.into_iter().collect()
427    }
428}
429
430// FIXME: this impl is a footgun
431impl<I, T, const N: usize> From<[T; N]> for Vector<I, T>
432where
433    I: Idx,
434{
435    fn from(v: [T; N]) -> Self {
436        v.into_iter().collect()
437    }
438}
439
440impl<I: Idx, T: Serialize> Serialize for Vector<I, T> {
441    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
442    where
443        S: Serializer,
444    {
445        self.vector.serialize(serializer)
446    }
447}
448
449impl<'de, I: Idx, T: Deserialize<'de>> Deserialize<'de> for Vector<I, T> {
450    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
451    where
452        D: serde::Deserializer<'de>,
453    {
454        let mut ret = Self {
455            vector: Deserialize::deserialize(deserializer)?,
456            elem_count: 0,
457        };
458        ret.elem_count = ret.iter().count();
459        Ok(ret)
460    }
461}
462
463impl<'s, I: Idx, T, V: Visit<'s, T>> Drive<'s, V> for Vector<I, T> {
464    fn drive_inner(&'s self, v: &mut V) -> ControlFlow<V::Break> {
465        for x in self {
466            v.visit(x)?;
467        }
468        Continue(())
469    }
470}
471impl<'s, I: Idx, T, V: VisitMut<'s, T>> DriveMut<'s, V> for Vector<I, T> {
472    fn drive_inner_mut(&'s mut self, v: &mut V) -> ControlFlow<V::Break> {
473        for x in self {
474            v.visit(x)?;
475        }
476        Continue(())
477    }
478}
charon_lib/ids/vector.rs

charon_lib/ids/
vector.rs
