1 //===- RangeAdapterTest.cpp - Unit tests for range adapters  --------------===//
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 #include "llvm/ADT/STLExtras.h"
10 #include "llvm/ADT/iterator_range.h"
11 #include "gtest/gtest.h"
12 
13 #include <iterator>
14 #include <list>
15 #include <vector>
16 
17 using namespace llvm;
18 
19 namespace {
20 
21 // A wrapper around vector which exposes rbegin(), rend().
22 class ReverseOnlyVector {
23   std::vector<int> Vec;
24 
25 public:
26   ReverseOnlyVector(std::initializer_list<int> list) : Vec(list) {}
27 
28   typedef std::vector<int>::reverse_iterator reverse_iterator;
29   typedef std::vector<int>::const_reverse_iterator const_reverse_iterator;
30   reverse_iterator rbegin() { return Vec.rbegin(); }
31   reverse_iterator rend() { return Vec.rend(); }
32   const_reverse_iterator rbegin() const { return Vec.rbegin(); }
33   const_reverse_iterator rend() const { return Vec.rend(); }
34 };
35 
36 // A wrapper around vector which exposes begin(), end(), rbegin() and rend().
37 // begin() and end() don't have implementations as this ensures that we will
38 // get a linker error if reverse() chooses begin()/end() over rbegin(), rend().
39 class BidirectionalVector {
40   mutable std::vector<int> Vec;
41 
42 public:
43   BidirectionalVector(std::initializer_list<int> list) : Vec(list) {}
44 
45   typedef std::vector<int>::iterator iterator;
46   iterator begin() const;
47   iterator end() const;
48 
49   typedef std::vector<int>::reverse_iterator reverse_iterator;
50   reverse_iterator rbegin() const { return Vec.rbegin(); }
51   reverse_iterator rend() const { return Vec.rend(); }
52 };
53 
54 /// This is the same as BidirectionalVector but with the addition of const
55 /// begin/rbegin methods to ensure that the type traits for has_rbegin works.
56 class BidirectionalVectorConsts {
57   std::vector<int> Vec;
58 
59 public:
60   BidirectionalVectorConsts(std::initializer_list<int> list) : Vec(list) {}
61 
62   typedef std::vector<int>::iterator iterator;
63   typedef std::vector<int>::const_iterator const_iterator;
64   iterator begin();
65   iterator end();
66   const_iterator begin() const;
67   const_iterator end() const;
68 
69   typedef std::vector<int>::reverse_iterator reverse_iterator;
70   typedef std::vector<int>::const_reverse_iterator const_reverse_iterator;
71   reverse_iterator rbegin() { return Vec.rbegin(); }
72   reverse_iterator rend() { return Vec.rend(); }
73   const_reverse_iterator rbegin() const { return Vec.rbegin(); }
74   const_reverse_iterator rend() const { return Vec.rend(); }
75 };
76 
77 /// Check that types with custom iterators work.
78 class CustomIteratorVector {
79   mutable std::vector<int> V;
80 
81 public:
82   CustomIteratorVector(std::initializer_list<int> list) : V(list) {}
83 
84   typedef std::vector<int>::iterator iterator;
85   class reverse_iterator {
86     std::vector<int>::iterator I;
87 
88   public:
89     reverse_iterator() = default;
90     reverse_iterator(const reverse_iterator &) = default;
91     reverse_iterator &operator=(const reverse_iterator &) = default;
92 
93     explicit reverse_iterator(std::vector<int>::iterator I) : I(I) {}
94 
95     reverse_iterator &operator++() {
96       --I;
97       return *this;
98     }
99     reverse_iterator &operator--() {
100       ++I;
101       return *this;
102     }
103     int &operator*() const { return *std::prev(I); }
104     int *operator->() const { return &*std::prev(I); }
105     friend bool operator==(const reverse_iterator &L,
106                            const reverse_iterator &R) {
107       return L.I == R.I;
108     }
109     friend bool operator!=(const reverse_iterator &L,
110                            const reverse_iterator &R) {
111       return !(L == R);
112     }
113   };
114 
115   iterator begin() const { return V.begin(); }
116   iterator end()  const { return V.end(); }
117   reverse_iterator rbegin() const { return reverse_iterator(V.end()); }
118   reverse_iterator rend() const { return reverse_iterator(V.begin()); }
119 };
120 
121 template <typename R> void TestRev(const R &r) {
122   int counter = 3;
123   for (int i : r)
124     EXPECT_EQ(i, counter--);
125 }
126 
127 // Test fixture
128 template <typename T> class RangeAdapterLValueTest : public ::testing::Test {};
129 
130 typedef ::testing::Types<std::vector<int>, std::list<int>, int[4]>
131     RangeAdapterLValueTestTypes;
132 TYPED_TEST_SUITE(RangeAdapterLValueTest, RangeAdapterLValueTestTypes, );
133 
134 TYPED_TEST(RangeAdapterLValueTest, TrivialOperation) {
135   TypeParam v = {0, 1, 2, 3};
136   TestRev(reverse(v));
137 
138   const TypeParam c = {0, 1, 2, 3};
139   TestRev(reverse(c));
140 }
141 
142 template <typename T> struct RangeAdapterRValueTest : testing::Test {};
143 
144 typedef ::testing::Types<std::vector<int>, std::list<int>, CustomIteratorVector,
145                          ReverseOnlyVector, BidirectionalVector,
146                          BidirectionalVectorConsts>
147     RangeAdapterRValueTestTypes;
148 TYPED_TEST_SUITE(RangeAdapterRValueTest, RangeAdapterRValueTestTypes, );
149 
150 TYPED_TEST(RangeAdapterRValueTest, TrivialOperation) {
151   TestRev(reverse(TypeParam({0, 1, 2, 3})));
152 }
153 
154 TYPED_TEST(RangeAdapterRValueTest, HasRbegin) {
155   static_assert(has_rbegin<TypeParam>::value, "rbegin() should be defined");
156 }
157 
158 TYPED_TEST(RangeAdapterRValueTest, RangeType) {
159   static_assert(
160       std::is_same<
161           decltype(reverse(*static_cast<TypeParam *>(nullptr)).begin()),
162           decltype(static_cast<TypeParam *>(nullptr)->rbegin())>::value,
163       "reverse().begin() should have the same type as rbegin()");
164   static_assert(
165       std::is_same<
166           decltype(reverse(*static_cast<const TypeParam *>(nullptr)).begin()),
167           decltype(static_cast<const TypeParam *>(nullptr)->rbegin())>::value,
168       "reverse().begin() should have the same type as rbegin() [const]");
169 }
170 
171 } // anonymous namespace
172