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