compiler/rustc_index/src/vec.rs

   1 use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
   2
   3 use std::fmt;
   4 use std::fmt::Debug;
   5 use std::hash::Hash;
   6 use std::iter::FromIterator;
   7 use std::marker::PhantomData;
   8 use std::ops::{Index, IndexMut, RangeBounds};
   9 use std::slice;
  10 use std::vec;
  11
  12 /// Represents some newtyped `usize` wrapper.
  13 ///
  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;
  17
  18     fn index(self) -> usize;
  19
  20     fn increment_by(&mut self, amount: usize) {
  21         *self = self.plus(amount);
  22     }
  23
  24     fn plus(self, amount: usize) -> Self {
  25         Self::new(self.index() + amount)
  26     }
  27 }
  28
  29 impl Idx for usize {
  30     #[inline]
  31     fn new(idx: usize) -> Self {
  32         idx
  33     }
  34     #[inline]
  35     fn index(self) -> usize {
  36         self
  37     }
  38 }
  39
  40 impl Idx for u32 {
  41     #[inline]
  42     fn new(idx: usize) -> Self {
  43         assert!(idx <= u32::MAX as usize);
  44         idx as u32
  45     }
  46     #[inline]
  47     fn index(self) -> usize {
  48         self as usize
  49     }
  50 }
  51
  52 #[derive(Clone, PartialEq, Eq, Hash)]
  53 pub struct IndexVec<I: Idx, T> {
  54     pub raw: Vec<T>,
  55     _marker: PhantomData<fn(&I)>,
  56 }
  57
  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 {}
  61
  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);
  65     }
  66 }
  67
  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 }
  71     }
  72 }
  73
  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)
  77     }
  78 }
  79
  80 impl<I: Idx, T> IndexVec<I, T> {
  81     #[inline]
  82     pub fn new() -> Self {
  83         IndexVec { raw: Vec::new(), _marker: PhantomData }
  84     }
  85
  86     #[inline]
  87     pub fn from_raw(raw: Vec<T>) -> Self {
  88         IndexVec { raw, _marker: PhantomData }
  89     }
  90
  91     #[inline]
  92     pub fn with_capacity(capacity: usize) -> Self {
  93         IndexVec { raw: Vec::with_capacity(capacity), _marker: PhantomData }
  94     }
  95
  96     #[inline]
  97     pub fn from_elem<S>(elem: T, universe: &IndexVec<I, S>) -> Self
  98     where
  99         T: Clone,
 100     {
 101         IndexVec { raw: vec![elem; universe.len()], _marker: PhantomData }
 102     }
 103
 104     #[inline]
 105     pub fn from_elem_n(elem: T, n: usize) -> Self
 106     where
 107         T: Clone,
 108     {
 109         IndexVec { raw: vec![elem; n], _marker: PhantomData }
 110     }
 111
 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`.)
 115     #[inline]
 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())
 119     }
 120
 121     #[inline]
 122     pub fn push(&mut self, d: T) -> I {
 123         let idx = I::new(self.len());
 124         self.raw.push(d);
 125         idx
 126     }
 127
 128     #[inline]
 129     pub fn pop(&mut self) -> Option<T> {
 130         self.raw.pop()
 131     }
 132
 133     #[inline]
 134     pub fn len(&self) -> usize {
 135         self.raw.len()
 136     }
 137
 138     /// Gives the next index that will be assigned when `push` is
 139     /// called.
 140     #[inline]
 141     pub fn next_index(&self) -> I {
 142         I::new(self.len())
 143     }
 144
 145     #[inline]
 146     pub fn is_empty(&self) -> bool {
 147         self.raw.is_empty()
 148     }
 149
 150     #[inline]
 151     pub fn into_iter(self) -> vec::IntoIter<T> {
 152         self.raw.into_iter()
 153     }
 154
 155     #[inline]
 156     pub fn into_iter_enumerated(
 157         self,
 158     ) -> impl DoubleEndedIterator<Item = (I, T)> + ExactSizeIterator {
 159         self.raw.into_iter().enumerate().map(|(n, t)| (I::new(n), t))
 160     }
 161
 162     #[inline]
 163     pub fn iter(&self) -> slice::Iter<'_, T> {
 164         self.raw.iter()
 165     }
 166
 167     #[inline]
 168     pub fn iter_enumerated(
 169         &self,
 170     ) -> impl DoubleEndedIterator<Item = (I, &T)> + ExactSizeIterator + '_ {
 171         self.raw.iter().enumerate().map(|(n, t)| (I::new(n), t))
 172     }
 173
 174     #[inline]
 175     pub fn indices(
 176         &self,
 177     ) -> impl DoubleEndedIterator<Item = I> + ExactSizeIterator + Clone + 'static {
 178         (0..self.len()).map(|n| I::new(n))
 179     }
 180
 181     #[inline]
 182     pub fn iter_mut(&mut self) -> slice::IterMut<'_, T> {
 183         self.raw.iter_mut()
 184     }
 185
 186     #[inline]
 187     pub fn iter_enumerated_mut(
 188         &mut self,
 189     ) -> impl DoubleEndedIterator<Item = (I, &mut T)> + ExactSizeIterator + '_ {
 190         self.raw.iter_mut().enumerate().map(|(n, t)| (I::new(n), t))
 191     }
 192
 193     #[inline]
 194     pub fn drain<'a, R: RangeBounds<usize>>(
 195         &'a mut self,
 196         range: R,
 197     ) -> impl Iterator<Item = T> + 'a {
 198         self.raw.drain(range)
 199     }
 200
 201     #[inline]
 202     pub fn drain_enumerated<'a, R: RangeBounds<usize>>(
 203         &'a mut self,
 204         range: R,
 205     ) -> impl Iterator<Item = (I, T)> + 'a {
 206         self.raw.drain(range).enumerate().map(|(n, t)| (I::new(n), t))
 207     }
 208
 209     #[inline]
 210     pub fn last(&self) -> Option<I> {
 211         self.len().checked_sub(1).map(I::new)
 212     }
 213
 214     #[inline]
 215     pub fn shrink_to_fit(&mut self) {
 216         self.raw.shrink_to_fit()
 217     }
 218
 219     #[inline]
 220     pub fn swap(&mut self, a: I, b: I) {
 221         self.raw.swap(a.index(), b.index())
 222     }
 223
 224     #[inline]
 225     pub fn truncate(&mut self, a: usize) {
 226         self.raw.truncate(a)
 227     }
 228
 229     #[inline]
 230     pub fn get(&self, index: I) -> Option<&T> {
 231         self.raw.get(index.index())
 232     }
 233
 234     #[inline]
 235     pub fn get_mut(&mut self, index: I) -> Option<&mut T> {
 236         self.raw.get_mut(index.index())
 237     }
 238
 239     /// Returns mutable references to two distinct elements, `a` and `b`.
 240     ///
 241     /// Panics if `a == b`.
 242     #[inline]
 243     pub fn pick2_mut(&mut self, a: I, b: I) -> (&mut T, &mut T) {
 244         let (ai, bi) = (a.index(), b.index());
 245         assert!(ai != bi);
 246
 247         if ai < bi {
 248             let (c1, c2) = self.raw.split_at_mut(bi);
 249             (&mut c1[ai], &mut c2[0])
 250         } else {
 251             let (c2, c1) = self.pick2_mut(b, a);
 252             (c1, c2)
 253         }
 254     }
 255
 256     /// Returns mutable references to three distinct elements.
 257     ///
 258     /// Panics if the elements are not distinct.
 259     #[inline]
 260     pub fn pick3_mut(&mut self, a: I, b: I, c: I) -> (&mut T, &mut T, &mut T) {
 261         let (ai, bi, ci) = (a.index(), b.index(), c.index());
 262         assert!(ai != bi && bi != ci && ci != ai);
 263         let len = self.raw.len();
 264         assert!(ai < len && bi < len && ci < len);
 265         let ptr = self.raw.as_mut_ptr();
 266         unsafe { (&mut *ptr.add(ai), &mut *ptr.add(bi), &mut *ptr.add(ci)) }
 267     }
 268
 269     pub fn convert_index_type<Ix: Idx>(self) -> IndexVec<Ix, T> {
 270         IndexVec { raw: self.raw, _marker: PhantomData }
 271     }
 272
 273     /// Grows the index vector so that it contains an entry for
 274     /// `elem`; if that is already true, then has no
 275     /// effect. Otherwise, inserts new values as needed by invoking
 276     /// `fill_value`.
 277     #[inline]
 278     pub fn ensure_contains_elem(&mut self, elem: I, fill_value: impl FnMut() -> T) {
 279         let min_new_len = elem.index() + 1;
 280         if self.len() < min_new_len {
 281             self.raw.resize_with(min_new_len, fill_value);
 282         }
 283     }
 284
 285     #[inline]
 286     pub fn resize_to_elem(&mut self, elem: I, fill_value: impl FnMut() -> T) {
 287         let min_new_len = elem.index() + 1;
 288         self.raw.resize_with(min_new_len, fill_value);
 289     }
 290 }
 291
 292 /// `IndexVec` is often used as a map, so it provides some map-like APIs.
 293 impl<I: Idx, T> IndexVec<I, Option<T>> {
 294     #[inline]
 295     pub fn insert(&mut self, index: I, value: T) -> Option<T> {
 296         self.ensure_contains_elem(index, || None);
 297         self[index].replace(value)
 298     }
 299
 300     #[inline]
 301     pub fn get_or_insert_with(&mut self, index: I, value: impl FnOnce() -> T) -> &mut T {
 302         self.ensure_contains_elem(index, || None);
 303         self[index].get_or_insert_with(value)
 304     }
 305
 306     #[inline]
 307     pub fn remove(&mut self, index: I) -> Option<T> {
 308         self.ensure_contains_elem(index, || None);
 309         self[index].take()
 310     }
 311 }
 312
 313 impl<I: Idx, T: Clone> IndexVec<I, T> {
 314     #[inline]
 315     pub fn resize(&mut self, new_len: usize, value: T) {
 316         self.raw.resize(new_len, value)
 317     }
 318 }
 319
 320 impl<I: Idx, T: Ord> IndexVec<I, T> {
 321     #[inline]
 322     pub fn binary_search(&self, value: &T) -> Result<I, I> {
 323         match self.raw.binary_search(value) {
 324             Ok(i) => Ok(Idx::new(i)),
 325             Err(i) => Err(Idx::new(i)),
 326         }
 327     }
 328 }
 329
 330 impl<I: Idx, T> Index<I> for IndexVec<I, T> {
 331     type Output = T;
 332
 333     #[inline]
 334     fn index(&self, index: I) -> &T {
 335         &self.raw[index.index()]
 336     }
 337 }
 338
 339 impl<I: Idx, T> IndexMut<I> for IndexVec<I, T> {
 340     #[inline]
 341     fn index_mut(&mut self, index: I) -> &mut T {
 342         &mut self.raw[index.index()]
 343     }
 344 }
 345
 346 impl<I: Idx, T> Default for IndexVec<I, T> {
 347     #[inline]
 348     fn default() -> Self {
 349         Self::new()
 350     }
 351 }
 352
 353 impl<I: Idx, T> Extend<T> for IndexVec<I, T> {
 354     #[inline]
 355     fn extend<J: IntoIterator<Item = T>>(&mut self, iter: J) {
 356         self.raw.extend(iter);
 357     }
 358
 359     #[inline]
 360     fn extend_one(&mut self, item: T) {
 361         self.raw.push(item);
 362     }
 363
 364     #[inline]
 365     fn extend_reserve(&mut self, additional: usize) {
 366         self.raw.reserve(additional);
 367     }
 368 }
 369
 370 impl<I: Idx, T> FromIterator<T> for IndexVec<I, T> {
 371     #[inline]
 372     fn from_iter<J>(iter: J) -> Self
 373     where
 374         J: IntoIterator<Item = T>,
 375     {
 376         IndexVec { raw: FromIterator::from_iter(iter), _marker: PhantomData }
 377     }
 378 }
 379
 380 impl<I: Idx, T> IntoIterator for IndexVec<I, T> {
 381     type Item = T;
 382     type IntoIter = vec::IntoIter<T>;
 383
 384     #[inline]
 385     fn into_iter(self) -> vec::IntoIter<T> {
 386         self.raw.into_iter()
 387     }
 388 }
 389
 390 impl<'a, I: Idx, T> IntoIterator for &'a IndexVec<I, T> {
 391     type Item = &'a T;
 392     type IntoIter = slice::Iter<'a, T>;
 393
 394     #[inline]
 395     fn into_iter(self) -> slice::Iter<'a, T> {
 396         self.raw.iter()
 397     }
 398 }
 399
 400 impl<'a, I: Idx, T> IntoIterator for &'a mut IndexVec<I, T> {
 401     type Item = &'a mut T;
 402     type IntoIter = slice::IterMut<'a, T>;
 403
 404     #[inline]
 405     fn into_iter(self) -> slice::IterMut<'a, T> {
 406         self.raw.iter_mut()
 407     }
 408 }
 409
 410 #[cfg(test)]
 411 mod tests;