1 //===- llvm/ADT/IndexedMap.h - An index map implementation ------*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file implements an indexed map. The index map template takes two 10 // types. The first is the mapped type and the second is a functor 11 // that maps its argument to a size_t. On instantiation a "null" value 12 // can be provided to be used as a "does not exist" indicator in the 13 // map. A member function grow() is provided that given the value of 14 // the maximally indexed key (the argument of the functor) makes sure 15 // the map has enough space for it. 16 // 17 //===----------------------------------------------------------------------===// 18 19 #ifndef LLVM_ADT_INDEXEDMAP_H 20 #define LLVM_ADT_INDEXEDMAP_H 21 22 #include "llvm/ADT/SmallVector.h" 23 #include "llvm/ADT/STLExtras.h" 24 #include <cassert> 25 26 namespace llvm { 27 28 template <typename T, typename ToIndexT = identity<unsigned>> 29 class IndexedMap { 30 using IndexT = typename ToIndexT::argument_type; 31 // Prefer SmallVector with zero inline storage over std::vector. IndexedMaps 32 // can grow very large and SmallVector grows more efficiently as long as T 33 // is trivially copyable. 34 using StorageT = SmallVector<T, 0>; 35 36 StorageT storage_; 37 T nullVal_; 38 ToIndexT toIndex_; 39 40 public: IndexedMap()41 IndexedMap() : nullVal_(T()) {} 42 IndexedMap(const T & val)43 explicit IndexedMap(const T& val) : nullVal_(val) {} 44 45 typename StorageT::reference operator[](IndexT n) { 46 assert(toIndex_(n) < storage_.size() && "index out of bounds!"); 47 return storage_[toIndex_(n)]; 48 } 49 50 typename StorageT::const_reference operator[](IndexT n) const { 51 assert(toIndex_(n) < storage_.size() && "index out of bounds!"); 52 return storage_[toIndex_(n)]; 53 } 54 reserve(typename StorageT::size_type s)55 void reserve(typename StorageT::size_type s) { 56 storage_.reserve(s); 57 } 58 resize(typename StorageT::size_type s)59 void resize(typename StorageT::size_type s) { 60 storage_.resize(s, nullVal_); 61 } 62 clear()63 void clear() { 64 storage_.clear(); 65 } 66 grow(IndexT n)67 void grow(IndexT n) { 68 unsigned NewSize = toIndex_(n) + 1; 69 if (NewSize > storage_.size()) 70 resize(NewSize); 71 } 72 inBounds(IndexT n)73 bool inBounds(IndexT n) const { 74 return toIndex_(n) < storage_.size(); 75 } 76 size()77 typename StorageT::size_type size() const { 78 return storage_.size(); 79 } 80 }; 81 82 } // end namespace llvm 83 84 #endif // LLVM_ADT_INDEXEDMAP_H 85