1//===- llvm/ADT/IndexedMap.h - An index map implementation ------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file implements an indexed map. The index map template takes two
11// types. The first is the mapped type and the second is a functor
12// that maps its argument to a size_t. On instantiation a "null" value
13// can be provided to be used as a "does not exist" indicator in the
14// map. A member function grow() is provided that given the value of
15// the maximally indexed key (the argument of the functor) makes sure
16// the map has enough space for it.
17//
18//===----------------------------------------------------------------------===//
19
20#ifndef LLVM_ADT_INDEXEDMAP_H
21#define LLVM_ADT_INDEXEDMAP_H
22
23#include "llvm/ADT/STLExtras.h"
24#include <cassert>
25#include <functional>
26#include <vector>
27
28namespace llvm {
29
30template <typename T, typename ToIndexT = llvm::identity<unsigned> >
31  class IndexedMap {
32    typedef typename ToIndexT::argument_type IndexT;
33    typedef std::vector<T> StorageT;
34    StorageT storage_;
35    T nullVal_;
36    ToIndexT toIndex_;
37
38  public:
39    IndexedMap() : nullVal_(T()) { }
40
41    explicit IndexedMap(const T& val) : nullVal_(val) { }
42
43    typename StorageT::reference operator[](IndexT n) {
44      assert(toIndex_(n) < storage_.size() && "index out of bounds!");
45      return storage_[toIndex_(n)];
46    }
47
48    typename StorageT::const_reference operator[](IndexT n) const {
49      assert(toIndex_(n) < storage_.size() && "index out of bounds!");
50      return storage_[toIndex_(n)];
51    }
52
53    void reserve(typename StorageT::size_type s) {
54      storage_.reserve(s);
55    }
56
57    void resize(typename StorageT::size_type s) {
58      storage_.resize(s, nullVal_);
59    }
60
61    void clear() {
62      storage_.clear();
63    }
64
65    void grow(IndexT n) {
66      unsigned NewSize = toIndex_(n) + 1;
67      if (NewSize > storage_.size())
68        resize(NewSize);
69    }
70
71    bool inBounds(IndexT n) const {
72      return toIndex_(n) < storage_.size();
73    }
74
75    typename StorageT::size_type size() const {
76      return storage_.size();
77    }
78  };
79
80} // End llvm namespace
81
82#endif
83