reference, declarationdefinition
definition → references, declarations, derived classes, virtual overrides
reference to multiple definitions → definitions
unreferenced
    1
    2
    3
    4
    5
    6
    7
    8
    9
   10
   11
   12
   13
   14
   15
   16
   17
   18
   19
   20
   21
   22
   23
   24
   25
   26
   27
   28
   29
   30
   31
   32
   33
   34
   35
   36
   37
   38
   39
   40
   41
   42
   43
   44
   45
   46
   47
   48
   49
   50
   51
   52
   53
   54
   55
   56
   57
   58
   59
   60
   61
   62
   63
   64
   65
   66
   67
   68
   69
   70
   71
   72
   73
   74
   75
   76
   77
   78
   79
   80
   81
   82
   83
   84
//===- llvm/ADT/IndexedMap.h - An index map implementation ------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements an indexed map. The index map template takes two
// types. The first is the mapped type and the second is a functor
// that maps its argument to a size_t. On instantiation a "null" value
// can be provided to be used as a "does not exist" indicator in the
// map. A member function grow() is provided that given the value of
// the maximally indexed key (the argument of the functor) makes sure
// the map has enough space for it.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_ADT_INDEXEDMAP_H
#define LLVM_ADT_INDEXEDMAP_H

#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/STLExtras.h"
#include <cassert>

namespace llvm {

template <typename T, typename ToIndexT = identity<unsigned>>
  class IndexedMap {
    using IndexT = typename ToIndexT::argument_type;
    // Prefer SmallVector with zero inline storage over std::vector. IndexedMaps
    // can grow very large and SmallVector grows more efficiently as long as T
    // is trivially copyable.
    using StorageT = SmallVector<T, 0>;

    StorageT storage_;
    T nullVal_;
    ToIndexT toIndex_;

  public:
    IndexedMap() : nullVal_(T()) {}

    explicit IndexedMap(const T& val) : nullVal_(val) {}

    typename StorageT::reference operator[](IndexT n) {
      assert(toIndex_(n) < storage_.size() && "index out of bounds!");
      return storage_[toIndex_(n)];
    }

    typename StorageT::const_reference operator[](IndexT n) const {
      assert(toIndex_(n) < storage_.size() && "index out of bounds!");
      return storage_[toIndex_(n)];
    }

    void reserve(typename StorageT::size_type s) {
      storage_.reserve(s);
    }

    void resize(typename StorageT::size_type s) {
      storage_.resize(s, nullVal_);
    }

    void clear() {
      storage_.clear();
    }

    void grow(IndexT n) {
      unsigned NewSize = toIndex_(n) + 1;
      if (NewSize > storage_.size())
        resize(NewSize);
    }

    bool inBounds(IndexT n) const {
      return toIndex_(n) < storage_.size();
    }

    typename StorageT::size_type size() const {
      return storage_.size();
    }
  };

} // end namespace llvm

#endif // LLVM_ADT_INDEXEDMAP_H