src/librustc_data_structures/indexed_vec.rs

   1 use std::fmt::Debug;
   2 use std::iter::{self, FromIterator};
   3 use std::slice;
   4 use std::marker::PhantomData;
   5 use std::ops::{Index, IndexMut, Range, RangeBounds};
   6 use std::fmt;
   7 use std::hash::Hash;
   8 use std::vec;
   9 use std::u32;
  10
  11 use rustc_serialize as serialize;
  12
  13 /// Represents some newtyped `usize` wrapper.
  14 ///
  15 /// Purpose: avoid mixing indexes for different bitvector domains.
  16 pub trait Idx: Copy + 'static + Ord + Debug + Hash {
  17     fn new(idx: usize) -> Self;
  18
  19     fn index(self) -> usize;
  20
  21     fn increment_by(&mut self, amount: usize) {
  22         let v = self.index() + amount;
  23         *self = Self::new(v);
  24     }
  25 }
  26
  27 impl Idx for usize {
  28     #[inline]
  29     fn new(idx: usize) -> Self { idx }
  30     #[inline]
  31     fn index(self) -> usize { self }
  32 }
  33
  34 impl Idx for u32 {
  35     #[inline]
  36     fn new(idx: usize) -> Self { assert!(idx <= u32::MAX as usize); idx as u32 }
  37     #[inline]
  38     fn index(self) -> usize { self as usize }
  39 }
  40
  41 /// Creates a struct type `S` that can be used as an index with
  42 /// `IndexVec` and so on.
  43 ///
  44 /// There are two ways of interacting with these indices:
  45 ///
  46 /// - The `From` impls are the preferred way. So you can do
  47 ///   `S::from(v)` with a `usize` or `u32`. And you can convert back
  48 ///   to an integer with `u32::from(s)`.
  49 ///
  50 /// - Alternatively, you can use the methods `S::new(v)` and `s.index()`
  51 ///   to create/return a value.
  52 ///
  53 /// Internally, the index uses a u32, so the index must not exceed
  54 /// `u32::MAX`. You can also customize things like the `Debug` impl,
  55 /// what traits are derived, and so forth via the macro.
  56 #[macro_export]
  57 macro_rules! newtype_index {
  58     // ---- public rules ----
  59
  60     // Use default constants
  61     ($(#[$attrs:meta])* $v:vis struct $name:ident { .. }) => (
  62         newtype_index!(
  63             // Leave out derives marker so we can use its absence to ensure it comes first
  64             @attrs        [$(#[$attrs])*]
  65             @type         [$name]
  66             // shave off 256 indices at the end to allow space for packing these indices into enums
  67             @max          [0xFFFF_FF00]
  68             @vis          [$v]
  69             @debug_format ["{}"]);
  70     );
  71
  72     // Define any constants
  73     ($(#[$attrs:meta])* $v:vis struct $name:ident { $($tokens:tt)+ }) => (
  74         newtype_index!(
  75             // Leave out derives marker so we can use its absence to ensure it comes first
  76             @attrs        [$(#[$attrs])*]
  77             @type         [$name]
  78             // shave off 256 indices at the end to allow space for packing these indices into enums
  79             @max          [0xFFFF_FF00]
  80             @vis          [$v]
  81             @debug_format ["{}"]
  82                           $($tokens)+);
  83     );
  84
  85     // ---- private rules ----
  86
  87     // Base case, user-defined constants (if any) have already been defined
  88     (@derives      [$($derives:ident,)*]
  89      @attrs        [$(#[$attrs:meta])*]
  90      @type         [$type:ident]
  91      @max          [$max:expr]
  92      @vis          [$v:vis]
  93      @debug_format [$debug_format:tt]) => (
  94         $(#[$attrs])*
  95         #[derive(Copy, PartialEq, Eq, Hash, PartialOrd, Ord, $($derives),*)]
  96         #[rustc_layout_scalar_valid_range_end($max)]
  97         $v struct $type {
  98             private: u32
  99         }
 100
 101         impl Clone for $type {
 102             fn clone(&self) -> Self {
 103                 *self
 104             }
 105         }
 106
 107         impl $type {
 108             $v const MAX_AS_U32: u32 = $max;
 109
 110             $v const MAX: $type = $type::from_u32_const($max);
 111
 112             #[inline]
 113             $v fn from_usize(value: usize) -> Self {
 114                 assert!(value <= ($max as usize));
 115                 unsafe {
 116                     $type::from_u32_unchecked(value as u32)
 117                 }
 118             }
 119
 120             #[inline]
 121             $v fn from_u32(value: u32) -> Self {
 122                 assert!(value <= $max);
 123                 unsafe {
 124                     $type::from_u32_unchecked(value)
 125                 }
 126             }
 127
 128             /// Hacky variant of `from_u32` for use in constants.
 129             /// This version checks the "max" constraint by using an
 130             /// invalid array dereference.
 131             #[inline]
 132             $v const fn from_u32_const(value: u32) -> Self {
 133                 // This will fail at const eval time unless `value <=
 134                 // max` is true (in which case we get the index 0).
 135                 // It will also fail at runtime, of course, but in a
 136                 // kind of wacky way.
 137                 let _ = ["out of range value used"][
 138                     !(value <= $max) as usize
 139                 ];
 140
 141                 unsafe {
 142                     $type { private: value }
 143                 }
 144             }
 145
 146             #[inline]
 147             $v const unsafe fn from_u32_unchecked(value: u32) -> Self {
 148                 unsafe { $type { private: value } }
 149             }
 150
 151             /// Extracts the value of this index as an integer.
 152             #[inline]
 153             $v fn index(self) -> usize {
 154                 self.as_usize()
 155             }
 156
 157             /// Extracts the value of this index as a `u32`.
 158             #[inline]
 159             $v fn as_u32(self) -> u32 {
 160                 self.private
 161             }
 162
 163             /// Extracts the value of this index as a `usize`.
 164             #[inline]
 165             $v fn as_usize(self) -> usize {
 166                 self.as_u32() as usize
 167             }
 168         }
 169
 170         impl Idx for $type {
 171             #[inline]
 172             fn new(value: usize) -> Self {
 173                 Self::from(value)
 174             }
 175
 176             #[inline]
 177             fn index(self) -> usize {
 178                 usize::from(self)
 179             }
 180         }
 181
 182         impl ::std::iter::Step for $type {
 183             #[inline]
 184             fn steps_between(start: &Self, end: &Self) -> Option<usize> {
 185                 <usize as ::std::iter::Step>::steps_between(
 186                     &Idx::index(*start),
 187                     &Idx::index(*end),
 188                 )
 189             }
 190
 191             #[inline]
 192             fn replace_one(&mut self) -> Self {
 193                 ::std::mem::replace(self, Self::new(1))
 194             }
 195
 196             #[inline]
 197             fn replace_zero(&mut self) -> Self {
 198                 ::std::mem::replace(self, Self::new(0))
 199             }
 200
 201             #[inline]
 202             fn add_one(&self) -> Self {
 203                 Self::new(Idx::index(*self) + 1)
 204             }
 205
 206             #[inline]
 207             fn sub_one(&self) -> Self {
 208                 Self::new(Idx::index(*self) - 1)
 209             }
 210
 211             #[inline]
 212             fn add_usize(&self, u: usize) -> Option<Self> {
 213                 Idx::index(*self).checked_add(u).map(Self::new)
 214             }
 215         }
 216
 217         impl From<$type> for u32 {
 218             #[inline]
 219             fn from(v: $type) -> u32 {
 220                 v.as_u32()
 221             }
 222         }
 223
 224         impl From<$type> for usize {
 225             #[inline]
 226             fn from(v: $type) -> usize {
 227                 v.as_usize()
 228             }
 229         }
 230
 231         impl From<usize> for $type {
 232             #[inline]
 233             fn from(value: usize) -> Self {
 234                 $type::from_usize(value)
 235             }
 236         }
 237
 238         impl From<u32> for $type {
 239             #[inline]
 240             fn from(value: u32) -> Self {
 241                 $type::from_u32(value)
 242             }
 243         }
 244
 245         newtype_index!(
 246             @handle_debug
 247             @derives      [$($derives,)*]
 248             @type         [$type]
 249             @debug_format [$debug_format]);
 250     );
 251
 252     // base case for handle_debug where format is custom. No Debug implementation is emitted.
 253     (@handle_debug
 254      @derives      [$($_derives:ident,)*]
 255      @type         [$type:ident]
 256      @debug_format [custom]) => ();
 257
 258     // base case for handle_debug, no debug overrides found, so use default
 259     (@handle_debug
 260      @derives      []
 261      @type         [$type:ident]
 262      @debug_format [$debug_format:tt]) => (
 263         impl ::std::fmt::Debug for $type {
 264             fn fmt(&self, fmt: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
 265                 write!(fmt, $debug_format, self.as_u32())
 266             }
 267         }
 268     );
 269
 270     // Debug is requested for derive, don't generate any Debug implementation.
 271     (@handle_debug
 272      @derives      [Debug, $($derives:ident,)*]
 273      @type         [$type:ident]
 274      @debug_format [$debug_format:tt]) => ();
 275
 276     // It's not Debug, so just pop it off the front of the derives stack and check the rest.
 277     (@handle_debug
 278      @derives      [$_derive:ident, $($derives:ident,)*]
 279      @type         [$type:ident]
 280      @debug_format [$debug_format:tt]) => (
 281         newtype_index!(
 282             @handle_debug
 283             @derives      [$($derives,)*]
 284             @type         [$type]
 285             @debug_format [$debug_format]);
 286     );
 287
 288     // Append comma to end of derives list if it's missing
 289     (@attrs        [$(#[$attrs:meta])*]
 290      @type         [$type:ident]
 291      @max          [$max:expr]
 292      @vis          [$v:vis]
 293      @debug_format [$debug_format:tt]
 294                    derive [$($derives:ident),*]
 295                    $($tokens:tt)*) => (
 296         newtype_index!(
 297             @attrs        [$(#[$attrs])*]
 298             @type         [$type]
 299             @max          [$max]
 300             @vis          [$v]
 301             @debug_format [$debug_format]
 302                           derive [$($derives,)*]
 303                           $($tokens)*);
 304     );
 305
 306     // By not including the @derives marker in this list nor in the default args, we can force it
 307     // to come first if it exists. When encodable is custom, just use the derives list as-is.
 308     (@attrs        [$(#[$attrs:meta])*]
 309      @type         [$type:ident]
 310      @max          [$max:expr]
 311      @vis          [$v:vis]
 312      @debug_format [$debug_format:tt]
 313                    derive [$($derives:ident,)+]
 314                    ENCODABLE = custom
 315                    $($tokens:tt)*) => (
 316         newtype_index!(
 317             @attrs        [$(#[$attrs])*]
 318             @derives      [$($derives,)+]
 319             @type         [$type]
 320             @max          [$max]
 321             @vis          [$v]
 322             @debug_format [$debug_format]
 323                           $($tokens)*);
 324     );
 325
 326     // By not including the @derives marker in this list nor in the default args, we can force it
 327     // to come first if it exists. When encodable isn't custom, add serialization traits by default.
 328     (@attrs        [$(#[$attrs:meta])*]
 329      @type         [$type:ident]
 330      @max          [$max:expr]
 331      @vis          [$v:vis]
 332      @debug_format [$debug_format:tt]
 333                    derive [$($derives:ident,)+]
 334                    $($tokens:tt)*) => (
 335         newtype_index!(
 336             @derives      [$($derives,)+ RustcEncodable,]
 337             @attrs        [$(#[$attrs])*]
 338             @type         [$type]
 339             @max          [$max]
 340             @vis          [$v]
 341             @debug_format [$debug_format]
 342                           $($tokens)*);
 343         newtype_index!(@decodable $type);
 344     );
 345
 346     // The case where no derives are added, but encodable is overridden. Don't
 347     // derive serialization traits
 348     (@attrs        [$(#[$attrs:meta])*]
 349      @type         [$type:ident]
 350      @max          [$max:expr]
 351      @vis          [$v:vis]
 352      @debug_format [$debug_format:tt]
 353                    ENCODABLE = custom
 354                    $($tokens:tt)*) => (
 355         newtype_index!(
 356             @derives      []
 357             @attrs        [$(#[$attrs])*]
 358             @type         [$type]
 359             @max          [$max]
 360             @vis          [$v]
 361             @debug_format [$debug_format]
 362                           $($tokens)*);
 363     );
 364
 365     // The case where no derives are added, add serialization derives by default
 366     (@attrs        [$(#[$attrs:meta])*]
 367      @type         [$type:ident]
 368      @max          [$max:expr]
 369      @vis          [$v:vis]
 370      @debug_format [$debug_format:tt]
 371                    $($tokens:tt)*) => (
 372         newtype_index!(
 373             @derives      [RustcEncodable,]
 374             @attrs        [$(#[$attrs])*]
 375             @type         [$type]
 376             @max          [$max]
 377             @vis          [$v]
 378             @debug_format [$debug_format]
 379                           $($tokens)*);
 380         newtype_index!(@decodable $type);
 381     );
 382
 383     (@decodable $type:ident) => (
 384         impl $type {
 385             fn __decodable__impl__hack() {
 386                 mod __more_hacks_because__self_doesnt_work_in_functions {
 387                     extern crate serialize;
 388                     use self::serialize::{Decodable, Decoder};
 389                     impl Decodable for super::$type {
 390                         fn decode<D: Decoder>(d: &mut D) -> Result<Self, D::Error> {
 391                             d.read_u32().map(Self::from)
 392                         }
 393                     }
 394                 }
 395             }
 396         }
 397     );
 398
 399     // Rewrite final without comma to one that includes comma
 400     (@derives      [$($derives:ident,)*]
 401      @attrs        [$(#[$attrs:meta])*]
 402      @type         [$type:ident]
 403      @max          [$max:expr]
 404      @vis          [$v:vis]
 405      @debug_format [$debug_format:tt]
 406                    $name:ident = $constant:expr) => (
 407         newtype_index!(
 408             @derives      [$($derives,)*]
 409             @attrs        [$(#[$attrs])*]
 410             @type         [$type]
 411             @max          [$max]
 412             @vis          [$v]
 413             @debug_format [$debug_format]
 414                           $name = $constant,);
 415     );
 416
 417     // Rewrite final const without comma to one that includes comma
 418     (@derives      [$($derives:ident,)*]
 419      @attrs        [$(#[$attrs:meta])*]
 420      @type         [$type:ident]
 421      @max          [$_max:expr]
 422      @vis          [$v:vis]
 423      @debug_format [$debug_format:tt]
 424                    $(#[doc = $doc:expr])*
 425                    const $name:ident = $constant:expr) => (
 426         newtype_index!(
 427             @derives      [$($derives,)*]
 428             @attrs        [$(#[$attrs])*]
 429             @type         [$type]
 430             @max          [$max]
 431             @vis          [$v]
 432             @debug_format [$debug_format]
 433                           $(#[doc = $doc])* const $name = $constant,);
 434     );
 435
 436     // Replace existing default for max
 437     (@derives      [$($derives:ident,)*]
 438      @attrs        [$(#[$attrs:meta])*]
 439      @type         [$type:ident]
 440      @max          [$_max:expr]
 441      @vis          [$v:vis]
 442      @debug_format [$debug_format:tt]
 443                    MAX = $max:expr,
 444                    $($tokens:tt)*) => (
 445         newtype_index!(
 446             @derives      [$($derives,)*]
 447             @attrs        [$(#[$attrs])*]
 448             @type         [$type]
 449             @max          [$max]
 450             @vis          [$v]
 451             @debug_format [$debug_format]
 452                           $($tokens)*);
 453     );
 454
 455     // Replace existing default for debug_format
 456     (@derives      [$($derives:ident,)*]
 457      @attrs        [$(#[$attrs:meta])*]
 458      @type         [$type:ident]
 459      @max          [$max:expr]
 460      @vis          [$v:vis]
 461      @debug_format [$_debug_format:tt]
 462                    DEBUG_FORMAT = $debug_format:tt,
 463                    $($tokens:tt)*) => (
 464         newtype_index!(
 465             @derives      [$($derives,)*]
 466             @attrs        [$(#[$attrs])*]
 467             @type         [$type]
 468             @max          [$max]
 469             @vis          [$v]
 470             @debug_format [$debug_format]
 471                           $($tokens)*);
 472     );
 473
 474     // Assign a user-defined constant
 475     (@derives      [$($derives:ident,)*]
 476      @attrs        [$(#[$attrs:meta])*]
 477      @type         [$type:ident]
 478      @max          [$max:expr]
 479      @vis          [$v:vis]
 480      @debug_format [$debug_format:tt]
 481                    $(#[doc = $doc:expr])*
 482                    const $name:ident = $constant:expr,
 483                    $($tokens:tt)*) => (
 484         $(#[doc = $doc])*
 485         pub const $name: $type = $type::from_u32_const($constant);
 486         newtype_index!(
 487             @derives      [$($derives,)*]
 488             @attrs        [$(#[$attrs])*]
 489             @type         [$type]
 490             @max          [$max]
 491             @vis          [$v]
 492             @debug_format [$debug_format]
 493                           $($tokens)*);
 494     );
 495 }
 496
 497 #[derive(Clone, PartialEq, Eq, Hash)]
 498 pub struct IndexVec<I: Idx, T> {
 499     pub raw: Vec<T>,
 500     _marker: PhantomData<fn(&I)>
 501 }
 502
 503 // Whether `IndexVec` is `Send` depends only on the data,
 504 // not the phantom data.
 505 unsafe impl<I: Idx, T> Send for IndexVec<I, T> where T: Send {}
 506
 507 impl<I: Idx, T: serialize::Encodable> serialize::Encodable for IndexVec<I, T> {
 508     fn encode<S: serialize::Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
 509         serialize::Encodable::encode(&self.raw, s)
 510     }
 511 }
 512
 513 impl<I: Idx, T: serialize::Decodable> serialize::Decodable for IndexVec<I, T> {
 514     fn decode<D: serialize::Decoder>(d: &mut D) -> Result<Self, D::Error> {
 515         serialize::Decodable::decode(d).map(|v| {
 516             IndexVec { raw: v, _marker: PhantomData }
 517         })
 518     }
 519 }
 520
 521 impl<I: Idx, T: fmt::Debug> fmt::Debug for IndexVec<I, T> {
 522     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
 523         fmt::Debug::fmt(&self.raw, fmt)
 524     }
 525 }
 526
 527 pub type Enumerated<I, J> = iter::Map<iter::Enumerate<J>, IntoIdx<I>>;
 528
 529 impl<I: Idx, T> IndexVec<I, T> {
 530     #[inline]
 531     pub fn new() -> Self {
 532         IndexVec { raw: Vec::new(), _marker: PhantomData }
 533     }
 534
 535     #[inline]
 536     pub fn from_raw(raw: Vec<T>) -> Self {
 537         IndexVec { raw, _marker: PhantomData }
 538     }
 539
 540     #[inline]
 541     pub fn with_capacity(capacity: usize) -> Self {
 542         IndexVec { raw: Vec::with_capacity(capacity), _marker: PhantomData }
 543     }
 544
 545     #[inline]
 546     pub fn from_elem<S>(elem: T, universe: &IndexVec<I, S>) -> Self
 547         where T: Clone
 548     {
 549         IndexVec { raw: vec![elem; universe.len()], _marker: PhantomData }
 550     }
 551
 552     #[inline]
 553     pub fn from_elem_n(elem: T, n: usize) -> Self
 554         where T: Clone
 555     {
 556         IndexVec { raw: vec![elem; n], _marker: PhantomData }
 557     }
 558
 559     #[inline]
 560     pub fn push(&mut self, d: T) -> I {
 561         let idx = I::new(self.len());
 562         self.raw.push(d);
 563         idx
 564     }
 565
 566     #[inline]
 567     pub fn pop(&mut self) -> Option<T> {
 568         self.raw.pop()
 569     }
 570
 571     #[inline]
 572     pub fn len(&self) -> usize {
 573         self.raw.len()
 574     }
 575
 576     /// Gives the next index that will be assigned when `push` is
 577     /// called.
 578     #[inline]
 579     pub fn next_index(&self) -> I {
 580         I::new(self.len())
 581     }
 582
 583     #[inline]
 584     pub fn is_empty(&self) -> bool {
 585         self.raw.is_empty()
 586     }
 587
 588     #[inline]
 589     pub fn into_iter(self) -> vec::IntoIter<T> {
 590         self.raw.into_iter()
 591     }
 592
 593     #[inline]
 594     pub fn into_iter_enumerated(self) -> Enumerated<I, vec::IntoIter<T>>
 595     {
 596         self.raw.into_iter().enumerate().map(IntoIdx { _marker: PhantomData })
 597     }
 598
 599     #[inline]
 600     pub fn iter(&self) -> slice::Iter<'_, T> {
 601         self.raw.iter()
 602     }
 603
 604     #[inline]
 605     pub fn iter_enumerated(&self) -> Enumerated<I, slice::Iter<'_, T>>
 606     {
 607         self.raw.iter().enumerate().map(IntoIdx { _marker: PhantomData })
 608     }
 609
 610     #[inline]
 611     pub fn indices(&self) -> iter::Map<Range<usize>, IntoIdx<I>> {
 612         (0..self.len()).map(IntoIdx { _marker: PhantomData })
 613     }
 614
 615     #[inline]
 616     pub fn iter_mut(&mut self) -> slice::IterMut<'_, T> {
 617         self.raw.iter_mut()
 618     }
 619
 620     #[inline]
 621     pub fn iter_enumerated_mut(&mut self) -> Enumerated<I, slice::IterMut<'_, T>>
 622     {
 623         self.raw.iter_mut().enumerate().map(IntoIdx { _marker: PhantomData })
 624     }
 625
 626     #[inline]
 627     pub fn drain<'a, R: RangeBounds<usize>>(
 628         &'a mut self, range: R) -> impl Iterator<Item=T> + 'a {
 629         self.raw.drain(range)
 630     }
 631
 632     #[inline]
 633     pub fn drain_enumerated<'a, R: RangeBounds<usize>>(
 634         &'a mut self, range: R) -> impl Iterator<Item=(I, T)> + 'a {
 635         self.raw.drain(range).enumerate().map(IntoIdx { _marker: PhantomData })
 636     }
 637
 638     #[inline]
 639     pub fn last(&self) -> Option<I> {
 640         self.len().checked_sub(1).map(I::new)
 641     }
 642
 643     #[inline]
 644     pub fn shrink_to_fit(&mut self) {
 645         self.raw.shrink_to_fit()
 646     }
 647
 648     #[inline]
 649     pub fn swap(&mut self, a: I, b: I) {
 650         self.raw.swap(a.index(), b.index())
 651     }
 652
 653     #[inline]
 654     pub fn truncate(&mut self, a: usize) {
 655         self.raw.truncate(a)
 656     }
 657
 658     #[inline]
 659     pub fn get(&self, index: I) -> Option<&T> {
 660         self.raw.get(index.index())
 661     }
 662
 663     #[inline]
 664     pub fn get_mut(&mut self, index: I) -> Option<&mut T> {
 665         self.raw.get_mut(index.index())
 666     }
 667
 668     /// Returns mutable references to two distinct elements, a and b. Panics if a == b.
 669     #[inline]
 670     pub fn pick2_mut(&mut self, a: I, b: I) -> (&mut T, &mut T) {
 671         let (ai, bi) = (a.index(), b.index());
 672         assert!(ai != bi);
 673
 674         if ai < bi {
 675             let (c1, c2) = self.raw.split_at_mut(bi);
 676             (&mut c1[ai], &mut c2[0])
 677         } else {
 678             let (c2, c1) = self.pick2_mut(b, a);
 679             (c1, c2)
 680         }
 681     }
 682
 683     pub fn convert_index_type<Ix: Idx>(self) -> IndexVec<Ix, T> {
 684         IndexVec {
 685             raw: self.raw,
 686             _marker: PhantomData,
 687         }
 688     }
 689 }
 690
 691 impl<I: Idx, T: Clone> IndexVec<I, T> {
 692     /// Grows the index vector so that it contains an entry for
 693     /// `elem`; if that is already true, then has no
 694     /// effect. Otherwise, inserts new values as needed by invoking
 695     /// `fill_value`.
 696     #[inline]
 697     pub fn ensure_contains_elem(&mut self, elem: I, fill_value: impl FnMut() -> T) {
 698         let min_new_len = elem.index() + 1;
 699         if self.len() < min_new_len {
 700             self.raw.resize_with(min_new_len, fill_value);
 701         }
 702     }
 703
 704     #[inline]
 705     pub fn resize(&mut self, new_len: usize, value: T) {
 706         self.raw.resize(new_len, value)
 707     }
 708
 709     #[inline]
 710     pub fn resize_to_elem(&mut self, elem: I, fill_value: impl FnMut() -> T) {
 711         let min_new_len = elem.index() + 1;
 712         self.raw.resize_with(min_new_len, fill_value);
 713     }
 714 }
 715
 716 impl<I: Idx, T: Ord> IndexVec<I, T> {
 717     #[inline]
 718     pub fn binary_search(&self, value: &T) -> Result<I, I> {
 719         match self.raw.binary_search(value) {
 720             Ok(i) => Ok(Idx::new(i)),
 721             Err(i) => Err(Idx::new(i)),
 722         }
 723     }
 724 }
 725
 726 impl<I: Idx, T> Index<I> for IndexVec<I, T> {
 727     type Output = T;
 728
 729     #[inline]
 730     fn index(&self, index: I) -> &T {
 731         &self.raw[index.index()]
 732     }
 733 }
 734
 735 impl<I: Idx, T> IndexMut<I> for IndexVec<I, T> {
 736     #[inline]
 737     fn index_mut(&mut self, index: I) -> &mut T {
 738         &mut self.raw[index.index()]
 739     }
 740 }
 741
 742 impl<I: Idx, T> Default for IndexVec<I, T> {
 743     #[inline]
 744     fn default() -> Self {
 745         Self::new()
 746     }
 747 }
 748
 749 impl<I: Idx, T> Extend<T> for IndexVec<I, T> {
 750     #[inline]
 751     fn extend<J: IntoIterator<Item = T>>(&mut self, iter: J) {
 752         self.raw.extend(iter);
 753     }
 754 }
 755
 756 impl<I: Idx, T> FromIterator<T> for IndexVec<I, T> {
 757     #[inline]
 758     fn from_iter<J>(iter: J) -> Self where J: IntoIterator<Item=T> {
 759         IndexVec { raw: FromIterator::from_iter(iter), _marker: PhantomData }
 760     }
 761 }
 762
 763 impl<I: Idx, T> IntoIterator for IndexVec<I, T> {
 764     type Item = T;
 765     type IntoIter = vec::IntoIter<T>;
 766
 767     #[inline]
 768     fn into_iter(self) -> vec::IntoIter<T> {
 769         self.raw.into_iter()
 770     }
 771
 772 }
 773
 774 impl<'a, I: Idx, T> IntoIterator for &'a IndexVec<I, T> {
 775     type Item = &'a T;
 776     type IntoIter = slice::Iter<'a, T>;
 777
 778     #[inline]
 779     fn into_iter(self) -> slice::Iter<'a, T> {
 780         self.raw.iter()
 781     }
 782 }
 783
 784 impl<'a, I: Idx, T> IntoIterator for &'a mut IndexVec<I, T> {
 785     type Item = &'a mut T;
 786     type IntoIter = slice::IterMut<'a, T>;
 787
 788     #[inline]
 789     fn into_iter(self) -> slice::IterMut<'a, T> {
 790         self.raw.iter_mut()
 791     }
 792 }
 793
 794 pub struct IntoIdx<I: Idx> { _marker: PhantomData<fn(&I)> }
 795 impl<I: Idx, T> FnOnce<((usize, T),)> for IntoIdx<I> {
 796     type Output = (I, T);
 797
 798     extern "rust-call" fn call_once(self, ((n, t),): ((usize, T),)) -> Self::Output {
 799         (I::new(n), t)
 800     }
 801 }
 802
 803 impl<I: Idx, T> FnMut<((usize, T),)> for IntoIdx<I> {
 804     extern "rust-call" fn call_mut(&mut self, ((n, t),): ((usize, T),)) -> Self::Output {
 805         (I::new(n), t)
 806     }
 807 }
 808
 809 impl<I: Idx> FnOnce<(usize,)> for IntoIdx<I> {
 810     type Output = I;
 811
 812     extern "rust-call" fn call_once(self, (n,): (usize,)) -> Self::Output {
 813         I::new(n)
 814     }
 815 }
 816
 817 impl<I: Idx> FnMut<(usize,)> for IntoIdx<I> {
 818     extern "rust-call" fn call_mut(&mut self, (n,): (usize,)) -> Self::Output {
 819         I::new(n)
 820     }
 821 }