Add initial tests for rehash(), reserve()

include/boost/unordered/concurrent_flat_map.hpp

@@ -742,6 +742,18 @@ namespace boost {
 
       /// Hash Policy
       ///
+      size_type bucket_count() const noexcept { 
+        return table_.capacity();
+      }
+
+      float load_factor() const noexcept { return table_.load_factor(); }
+      float max_load_factor() const noexcept
+      {
+        return table_.max_load_factor();
+      };
+      void max_load_factor(float) {}
+      size_type max_load() const noexcept { return table_.max_load(); }
+
       void rehash(size_type n) { table_.rehash(n); }
       void reserve(size_type n) { table_.reserve(n); }
 

test/Jamfile.v2

@@ -187,6 +187,7 @@ local CFOA_TESTS =
   clear_tests
   swap_tests
   merge_tests
+  rehash_tests
 ;
 
 for local test in $(CFOA_TESTS)

test/cfoa/helpers.hpp

@@ -16,6 +16,7 @@
 
 #include <algorithm>
 #include <atomic>
+#include <cmath>
 #include <condition_variable>
 #include <cstddef>
 #include <iostream>
@@ -398,7 +399,7 @@ void check_raii_counts()
     raii::destructor);
 }
 
-template <class T> void shuffle_values(std::vector<T> v)
+template <class T> void shuffle_values(std::vector<T>& v)
 {
   std::random_device rd;
   std::mt19937 g(rd());

test/cfoa/rehash_tests.cpp

@@ -0,0 +1,181 @@
+// Copyright (C) 2023 Christian Mazakas
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#include "helpers.hpp"
+
+#include <boost/unordered/concurrent_flat_map.hpp>
+
+using test::default_generator;
+using test::limited_range;
+using test::sequential;
+
+using hasher = stateful_hash;
+using key_equal = stateful_key_equal;
+using allocator_type = stateful_allocator<std::pair<raii const, raii> >;
+
+using map_type = boost::unordered::concurrent_flat_map<raii, raii, hasher,
+  key_equal, allocator_type>;
+
+using map_value_type = typename map_type::value_type;
+
+namespace {
+  test::seed_t initialize_seed{748775921};
+
+  UNORDERED_AUTO_TEST (rehash_no_insert) {
+    map_type x(0, hasher(1), key_equal(2), allocator_type(3));
+    BOOST_TEST_EQ(x.bucket_count(), 0u);
+
+    x.rehash(1024);
+    BOOST_TEST_GE(x.bucket_count(), 1024u);
+
+    x.rehash(512);
+    BOOST_TEST_GE(x.bucket_count(), 512u);
+    BOOST_TEST_LT(x.bucket_count(), 1024u);
+
+    x.rehash(0);
+    BOOST_TEST_EQ(x.bucket_count(), 0u);
+  }
+
+  UNORDERED_AUTO_TEST (reserve_no_insert) {
+    using size_type = map_type::size_type;
+
+    map_type x(0, hasher(1), key_equal(2), allocator_type(3));
+
+    auto f = [&x](double c) {
+      return static_cast<size_type>(std::ceil(c / x.max_load_factor()));
+    };
+
+    BOOST_TEST_EQ(x.bucket_count(), f(0.0));
+
+    x.reserve(1024);
+    BOOST_TEST_GE(x.bucket_count(), f(1024.0));
+
+    x.reserve(512);
+    BOOST_TEST_GE(x.bucket_count(), f(512.0));
+    BOOST_TEST_LT(x.bucket_count(), f(1024.0));
+
+    x.reserve(0);
+    BOOST_TEST_EQ(x.bucket_count(), f(0.0));
+  }
+
+  template <class G>
+  void insert_and_erase_with_rehash(G gen, test::random_generator rg)
+  {
+    auto vals1 = make_random_values(1024 * 8, [&] { return gen(rg); });
+
+    auto erase_indices = std::vector<std::size_t>(vals1.size());
+    for (std::size_t idx = 0; idx < erase_indices.size(); ++idx) {
+      erase_indices[idx] = idx;
+    }
+    shuffle_values(erase_indices);
+
+    auto ref_map = boost::unordered_flat_map<raii, raii>();
+    ref_map.insert(vals1.begin(), vals1.end());
+
+    {
+      raii::reset_counts();
+
+      map_type x(0, hasher(1), key_equal(2), allocator_type(3));
+
+      std::thread t1, t2, t3;
+      boost::latch l(2);
+
+      std::mutex m;
+      std::condition_variable cv;
+      std::atomic_bool done1{false}, done2{false};
+      std::atomic<unsigned long long> call_count{0};
+      bool ready = false;
+
+      auto const old_mc = +raii::move_constructor;
+      BOOST_TEST_EQ(old_mc, 0u);
+
+      t1 = std::thread([&x, &vals1, &l, &done1, &cv, &ready, &m] {
+        l.arrive_and_wait();
+
+        for (std::size_t idx = 0; idx < vals1.size(); ++idx) {
+          auto const& val = vals1[idx];
+          x.insert(val);
+
+          if (idx % (vals1.size() / 128) == 0) {
+            {
+              std::unique_lock<std::mutex> lk(m);
+              ready = true;
+            }
+            cv.notify_all();
+            std::this_thread::yield();
+          }
+        }
+
+        done1 = true;
+        {
+          std::unique_lock<std::mutex> lk(m);
+          ready = true;
+        }
+        cv.notify_all();
+      });
+
+      t2 =
+        std::thread([&x, &vals1, &erase_indices, &l, &done2, &cv, &m, &ready] {
+          l.arrive_and_wait();
+
+          for (std::size_t idx = 0; idx < erase_indices.size(); ++idx) {
+            auto const& val = vals1[erase_indices[idx]];
+            x.erase(val.first);
+            if (idx % 100 == 0) {
+              std::this_thread::yield();
+            }
+          }
+
+          done2 = true;
+          {
+            std::unique_lock<std::mutex> lk(m);
+            ready = true;
+          }
+          cv.notify_all();
+        });
+
+      t3 =
+        std::thread([&x, &vals1, &m, &cv, &done1, &done2, &call_count, &ready] {
+          while (x.empty()) {
+          }
+
+          do {
+            {
+              std::unique_lock<std::mutex> lk(m);
+              cv.wait(lk, [&ready] { return ready; });
+              ready = false;
+            }
+
+            auto const bc = static_cast<std::size_t>(rand()) % vals1.size();
+            x.rehash(bc);
+            call_count += 1;
+
+            std::this_thread::yield();
+          } while (!done1 || !done2);
+
+          BOOST_TEST(done1);
+          BOOST_TEST(done2);
+        });
+
+      t1.join();
+      t2.join();
+      t3.join();
+
+      BOOST_TEST_GT(call_count, 1u);
+
+      test_fuzzy_matches_reference(x, ref_map, rg);
+    }
+
+    check_raii_counts();
+  }
+} // namespace
+
+// clang-format off
+UNORDERED_TEST(
+  insert_and_erase_with_rehash,
+  ((value_type_generator))
+  ((default_generator)(sequential)(limited_range)))
+// clang-format on
+
+RUN_TESTS()