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/SmallVector.h" 24 #include "llvm/ADT/STLExtras.h" 25 #include <cassert> 26 27 namespace llvm { 28 29 template <typename T, typename ToIndexT = identity<unsigned>> 30 class IndexedMap { 31 using IndexT = typename ToIndexT::argument_type; 32 // Prefer SmallVector with zero inline storage over std::vector. IndexedMaps 33 // can grow very large and SmallVector grows more efficiently as long as T 34 // is trivially copyable. 35 using StorageT = SmallVector<T, 0>; 36 37 StorageT storage_; 38 T nullVal_; 39 ToIndexT toIndex_; 40 41 public: 42 IndexedMap() : nullVal_(T()) {} 43 44 explicit IndexedMap(const T& val) : nullVal_(val) {} 45 46 typename StorageT::reference operator[](IndexT n) { 47 assert(toIndex_(n) < storage_.size() && "index out of bounds!"); 48 return storage_[toIndex_(n)]; 49 } 50 51 typename StorageT::const_reference operator[](IndexT n) const { 52 assert(toIndex_(n) < storage_.size() && "index out of bounds!"); 53 return storage_[toIndex_(n)]; 54 } 55 56 void reserve(typename StorageT::size_type s) { 57 storage_.reserve(s); 58 } 59 60 void resize(typename StorageT::size_type s) { 61 storage_.resize(s, nullVal_); 62 } 63 64 void clear() { 65 storage_.clear(); 66 } 67 68 void grow(IndexT n) { 69 unsigned NewSize = toIndex_(n) + 1; 70 if (NewSize > storage_.size()) 71 resize(NewSize); 72 } 73 74 bool inBounds(IndexT n) const { 75 return toIndex_(n) < storage_.size(); 76 } 77 78 typename StorageT::size_type size() const { 79 return storage_.size(); 80 } 81 }; 82 83 } // end namespace llvm 84 85 #endif // LLVM_ADT_INDEXEDMAP_H 86
