xref: /aosp_15_r20/external/pigweed/pw_containers/examples/intrusive_multiset.cc (revision 61c4878ac05f98d0ceed94b57d316916de578985)
1 // Copyright 2024 The Pigweed Authors
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License"); you may not
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5 // the License at
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7 //     https://www.apache.org/licenses/LICENSE-2.0
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9 // Unless required by applicable law or agreed to in writing, software
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12 // License for the specific language governing permissions and limitations under
13 // the License.
14 
15 #include "pw_containers/intrusive_multiset.h"
16 
17 #include "pw_unit_test/framework.h"
18 
19 namespace examples {
20 
21 // DOCSTAG: [pw_containers-intrusive_multiset]
22 
23 class Book : public pw::IntrusiveMultiSet<Book>::Item {
24  private:
25   using Item = pw::IntrusiveMultiSet<Book>::Item;
26 
27  public:
Book(const char * name)28   explicit Book(const char* name) : name_(name) {}
name() const29   const char* name() const { return name_; }
operator <(const Book & rhs) const30   bool operator<(const Book& rhs) const {
31     return strcmp(name_, rhs.name()) < 0;
32   }
33 
34  private:
35   const char* name_;
36 };
37 
38 std::array<Book, 12> books = {
39     Book("The Little Prince"),
40     Book("Harry Potter and the Philosopher's Stone"),
41     Book("Harry Potter and the Philosopher's Stone"),
42     Book("Harry Potter and the Philosopher's Stone"),
43     Book("Harry Potter and the Philosopher's Stone"),
44     Book("Harry Potter and the Philosopher's Stone"),
45     Book("The Hobbit"),
46     Book("The Hobbit"),
47     Book("The Hobbit"),
48     Book("The Hobbit"),
49     Book("Alice's Adventures in Wonderland"),
50     Book("Alice's Adventures in Wonderland"),
51 };
52 pw::IntrusiveMultiSet<Book> library(books.begin(), books.end());
53 
VisitLibrary(pw::IntrusiveMultiSet<Book> & book_bag)54 void VisitLibrary(pw::IntrusiveMultiSet<Book>& book_bag) {
55   // Pick out some new books to read to the kids, but only if they're available.
56   std::array<const char*, 3> titles = {
57       "The Hobbit",
58       "Alice's Adventures in Wonderland",
59       "The Little Prince",
60   };
61   for (const char* title : titles) {
62     Book requested(title);
63     auto iter = library.find(requested);
64     if (iter != library.end()) {
65       Book& book = *iter;
66       library.erase(iter);
67       book_bag.insert(book);
68     }
69   }
70 }
71 
72 // DOCSTAG: [pw_containers-intrusive_multiset]
73 
74 }  // namespace examples
75 
76 namespace {
77 
TEST(IntrusiveMultiSetExampleTest,VisitLibrary)78 TEST(IntrusiveMultiSetExampleTest, VisitLibrary) {
79   pw::IntrusiveMultiSet<examples::Book> book_bag1;
80   examples::VisitLibrary(book_bag1);
81 
82   pw::IntrusiveMultiSet<examples::Book> book_bag2;
83   examples::VisitLibrary(book_bag2);
84 
85   pw::IntrusiveMultiSet<examples::Book> book_bag3;
86   examples::VisitLibrary(book_bag3);
87 
88   auto iter = book_bag1.begin();
89   ASSERT_NE(iter, book_bag1.end());
90   EXPECT_STREQ((iter++)->name(), "Alice's Adventures in Wonderland");
91   ASSERT_NE(iter, book_bag1.end());
92   EXPECT_STREQ((iter++)->name(), "The Hobbit");
93   ASSERT_NE(iter, book_bag1.end());
94   EXPECT_STREQ((iter++)->name(), "The Little Prince");
95   EXPECT_EQ(iter, book_bag1.end());
96   book_bag1.clear();
97 
98   iter = book_bag2.begin();
99   ASSERT_NE(iter, book_bag2.end());
100   EXPECT_STREQ((iter++)->name(), "Alice's Adventures in Wonderland");
101   ASSERT_NE(iter, book_bag2.end());
102   EXPECT_STREQ((iter++)->name(), "The Hobbit");
103   EXPECT_EQ(iter, book_bag2.end());
104   book_bag2.clear();
105 
106   iter = book_bag3.begin();
107   ASSERT_NE(iter, book_bag3.end());
108   EXPECT_STREQ((iter++)->name(), "The Hobbit");
109   EXPECT_EQ(iter, book_bag3.end());
110   book_bag3.clear();
111 
112   examples::library.clear();
113 }
114 
115 }  // namespace
116