1//===- ContinuousRangeMap.h - Map with int range as key ---------*- 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 defines the ContinuousRangeMap class, which is a highly
10// specialized container used by serialization.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_CLANG_SERIALIZATION_CONTINUOUSRANGEMAP_H
15#define LLVM_CLANG_SERIALIZATION_CONTINUOUSRANGEMAP_H
16
17#include "clang/Basic/LLVM.h"
18#include "llvm/ADT/STLExtras.h"
19#include "llvm/ADT/SmallVector.h"
20#include <algorithm>
21#include <cassert>
22#include <utility>
23
24namespace clang {
25
26/// A map from continuous integer ranges to some value, with a very
27/// specialized interface.
28///
29/// CRM maps from integer ranges to values. The ranges are continuous, i.e.
30/// where one ends, the next one begins. So if the map contains the stops I0-3,
31/// the first range is from I0 to I1, the second from I1 to I2, the third from
32/// I2 to I3 and the last from I3 to infinity.
33///
34/// Ranges must be inserted in order. Inserting a new stop I4 into the map will
35/// shrink the fourth range to I3 to I4 and add the new range I4 to inf.
36template <typename Int, typename V, unsigned InitialCapacity>
37class ContinuousRangeMap {
38public:
39 using value_type = std::pair<Int, V>;
40 using reference = value_type &;
41 using const_reference = const value_type &;
42 using pointer = value_type *;
43 using const_pointer = const value_type *;
44
45private:
46 using Representation = SmallVector<value_type, InitialCapacity>;
47
48 Representation Rep;
49
50 struct Compare {
51 bool operator ()(const_reference L, Int R) const {
52 return L.first < R;
53 }
54 bool operator ()(Int L, const_reference R) const {
55 return L < R.first;
56 }
57 bool operator ()(Int L, Int R) const {
58 return L < R;
59 }
60 bool operator ()(const_reference L, const_reference R) const {
61 return L.first < R.first;
62 }
63 };
64
65public:
66 void insert(const value_type &Val) {
67 if (!Rep.empty() && Rep.back() == Val)
68 return;
69
70 assert((Rep.empty() || Rep.back().first < Val.first) &&
71 "Must insert keys in order.");
72 Rep.push_back(Val);
73 }
74
75 void insertOrReplace(const value_type &Val) {
76 iterator I = llvm::lower_bound(Rep, Val, Compare());
77 if (I != Rep.end() && I->first == Val.first) {
78 I->second = Val.second;
79 return;
80 }
81
82 Rep.insert(I, Val);
83 }
84
85 using iterator = typename Representation::iterator;
86 using const_iterator = typename Representation::const_iterator;
87
88 iterator begin() { return Rep.begin(); }
89 iterator end() { return Rep.end(); }
90 const_iterator begin() const { return Rep.begin(); }
91 const_iterator end() const { return Rep.end(); }
92
93 iterator find(Int K) {
94 iterator I = llvm::upper_bound(Rep, K, Compare());
95 // I points to the first entry with a key > K, which is the range that
96 // follows the one containing K.
97 if (I == Rep.begin())
98 return Rep.end();
99 --I;
100 return I;
101 }
102 const_iterator find(Int K) const {
103 return const_cast<ContinuousRangeMap*>(this)->find(K);
104 }
105
106 reference back() { return Rep.back(); }
107 const_reference back() const { return Rep.back(); }
108
109 /// An object that helps properly build a continuous range map
110 /// from a set of values.
111 class Builder {
112 ContinuousRangeMap &Self;
113
114 public:
115 explicit Builder(ContinuousRangeMap &Self) : Self(Self) {}
116 Builder(const Builder&) = delete;
117 Builder &operator=(const Builder&) = delete;
118
119 ~Builder() {
120 llvm::sort(Self.Rep, Compare());
121 Self.Rep.erase(
122 std::unique(
123 Self.Rep.begin(), Self.Rep.end(),
124 [](const_reference A, const_reference B) {
125 // FIXME: we should not allow any duplicate keys, but there are
126 // a lot of duplicate 0 -> 0 mappings to remove first.
127 assert((A == B || A.first != B.first) &&
128 "ContinuousRangeMap::Builder given non-unique keys");
129 return A == B;
130 }),
131 Self.Rep.end());
132 }
133
134 void insert(const value_type &Val) {
135 Self.Rep.push_back(Val);
136 }
137 };
138
139 friend class Builder;
140};
141
142} // namespace clang
143
144#endif // LLVM_CLANG_SERIALIZATION_CONTINUOUSRANGEMAP_H
145

source code of clang/include/clang/Serialization/ContinuousRangeMap.h