1 //===- DenseMap.h - A dense map implmentation -------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements a dense map. A dense 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.
18 //===----------------------------------------------------------------------===//
20 #ifndef SUPPORT_DENSEMAP_H
21 #define SUPPORT_DENSEMAP_H
27 struct IdentityFunctor : std::unary_function<unsigned, unsigned> {
28 unsigned operator()(unsigned Index) const {
33 template <typename T, typename ToIndexT = IdentityFunctor>
35 typedef typename ToIndexT::argument_type IndexT;
36 typedef std::vector<T> StorageT;
42 DenseMap() : nullVal_(T()) { }
44 explicit DenseMap(const T& val) : nullVal_(val) { }
46 typename StorageT::reference operator[](IndexT n) {
47 assert(toIndex_(n) < storage_.size() && "index out of bounds!");
48 return storage_[toIndex_(n)];
51 typename StorageT::const_reference operator[](IndexT n) const {
52 assert(toIndex_(n) < storage_.size() && "index out of bounds!");
53 return storage_[toIndex_(n)];
61 unsigned NewSize = toIndex_(n) + 1;
62 if (NewSize > storage_.size())
63 storage_.resize(NewSize, nullVal_);
67 } // End llvm namespace