1//===----------------------------------------------------------------------===//
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// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
10
11#include <algorithm>
12#include <cassert>
13#include <cstddef>
14#include <deque>
15#include <iterator>
16#include <list>
17#include <vector>
18
19#include <benchmark/benchmark.h>
20#include "../../GenerateInput.h"
21
22int main(int argc, char** argv) {
23 // Benchmark ranges::contains_subrange where we never find the needle, which is the
24 // worst case.
25 {
26 auto bm = []<class Container>(std::string name) {
27 benchmark::RegisterBenchmark(
28 name,
29 [](auto& st) {
30 std::size_t const size = st.range(0);
31 using ValueType = typename Container::value_type;
32 ValueType x = Generate<ValueType>::random();
33 ValueType y = random_different_from({x});
34 Container haystack(size, x);
35 std::size_t n = size / 10; // needle size is 10% of the haystack, but we'll never find it
36 assert(n > 0);
37 Container needle(n, y);
38
39 for ([[maybe_unused]] auto _ : st) {
40 benchmark::DoNotOptimize(haystack);
41 benchmark::DoNotOptimize(needle);
42 auto result = std::ranges::contains_subrange(haystack, needle);
43 benchmark::DoNotOptimize(result);
44 }
45 })
46 ->Arg(16)
47 ->Arg(32)
48 ->Arg(50) // non power-of-two
49 ->Arg(8192)
50 ->Arg(1 << 20);
51 };
52 bm.operator()<std::vector<int>>(name: "rng::contains_subrange(vector<int>) (process all)");
53 bm.operator()<std::deque<int>>(name: "rng::contains_subrange(deque<int>) (process all)");
54 bm.operator()<std::list<int>>(name: "rng::contains_subrange(list<int>) (process all)");
55 }
56
57 // Benchmark ranges::contains_subrange where we intersperse "near matches" inside the haystack.
58 {
59 auto bm = []<class Container>(std::string name) {
60 benchmark::RegisterBenchmark(
61 name,
62 [](auto& st) {
63 std::size_t const size = st.range(0);
64 using ValueType = typename Container::value_type;
65 ValueType x = Generate<ValueType>::random();
66 ValueType y = random_different_from({x});
67 Container haystack(size, x);
68 std::size_t n = size / 10; // needle size is 10% of the haystack, but we'll never find it
69 assert(n > 0);
70 Container needle(n, y);
71
72 // intersperse near-matches inside the haystack
73 {
74 auto first = haystack.begin();
75 for (int i = 0; i != 10; ++i) {
76 first = std::copy_n(needle.begin(), n - 1, first);
77 ++first; // this causes the subsequence not to match because it has length n-1
78 }
79 }
80
81 for ([[maybe_unused]] auto _ : st) {
82 benchmark::DoNotOptimize(haystack);
83 benchmark::DoNotOptimize(needle);
84 auto result = std::ranges::contains_subrange(haystack, needle);
85 benchmark::DoNotOptimize(result);
86 }
87 })
88 ->Arg(1000) // non power-of-two
89 ->Arg(1024)
90 ->Arg(8192);
91 };
92 bm.operator()<std::vector<int>>(name: "rng::contains_subrange(vector<int>) (near matches)");
93 bm.operator()<std::deque<int>>(name: "rng::contains_subrange(deque<int>) (near matches)");
94 bm.operator()<std::list<int>>(name: "rng::contains_subrange(list<int>) (near matches)");
95 }
96
97 // Special case: the two ranges are the same length (and they are equal, which is the worst case).
98 {
99 auto bm = []<class Container>(std::string name) {
100 benchmark::RegisterBenchmark(
101 name,
102 [](auto& st) {
103 std::size_t const size = st.range(0);
104 using ValueType = typename Container::value_type;
105 ValueType x = Generate<ValueType>::random();
106 Container haystack(size, x);
107 Container needle(size, x);
108
109 for ([[maybe_unused]] auto _ : st) {
110 benchmark::DoNotOptimize(haystack);
111 benchmark::DoNotOptimize(needle);
112 auto result = std::ranges::contains_subrange(haystack, needle);
113 benchmark::DoNotOptimize(result);
114 }
115 })
116 ->Arg(16)
117 ->Arg(32)
118 ->Arg(50) // non power-of-two
119 ->Arg(8192)
120 ->Arg(1 << 20);
121 };
122 bm.operator()<std::vector<int>>(name: "rng::contains_subrange(vector<int>) (same length)");
123 bm.operator()<std::deque<int>>(name: "rng::contains_subrange(deque<int>) (same length)");
124 bm.operator()<std::list<int>>(name: "rng::contains_subrange(list<int>) (same length)");
125 }
126
127 // Special case: the needle contains a single element (which we never find, i.e. the worst case).
128 {
129 auto bm = []<class Container>(std::string name) {
130 benchmark::RegisterBenchmark(
131 name,
132 [](auto& st) {
133 std::size_t const size = st.range(0);
134 using ValueType = typename Container::value_type;
135 ValueType x = Generate<ValueType>::random();
136 ValueType y = random_different_from({x});
137 Container haystack(size, x);
138 Container needle(1, y);
139
140 for ([[maybe_unused]] auto _ : st) {
141 benchmark::DoNotOptimize(haystack);
142 benchmark::DoNotOptimize(needle);
143 auto result = std::ranges::contains_subrange(haystack, needle);
144 benchmark::DoNotOptimize(result);
145 }
146 })
147 ->Arg(16)
148 ->Arg(32)
149 ->Arg(50) // non power-of-two
150 ->Arg(8192)
151 ->Arg(1 << 20);
152 };
153 bm.operator()<std::vector<int>>(name: "rng::contains_subrange(vector<int>) (single element)");
154 bm.operator()<std::deque<int>>(name: "rng::contains_subrange(deque<int>) (single element)");
155 bm.operator()<std::list<int>>(name: "rng::contains_subrange(list<int>) (single element)");
156 }
157
158 benchmark::Initialize(&argc, argv);
159 benchmark::RunSpecifiedBenchmarks();
160 benchmark::Shutdown();
161 return 0;
162}
163

source code of libcxx/test/benchmarks/algorithms/nonmodifying/contains_subrange.bench.cpp