hash-it.cc

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/*
                          Aleph_w
 
  Data structures & Algorithms
  version 2.0.0b
  https://github.com/lrleon/Aleph-w
 
  This file is part of Aleph-w library
 
  Copyright (c) 2002-2026 Leandro Rabindranath Leon
 
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:
 
  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.
 
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  SOFTWARE.
*/
 
 
# include <gtest/gtest.h>
 
# include <ahFunctional.H>
# include <ahSort.H>
# include <tpl_dynMapOhash.H>
# include <tpl_dynSetHash.H>
# include <tpl_olhash.H>
# include <tpl_odhash.H>
# include <tpl_lhash.H>
# include <stdexcept>
# include <functional>
 
using namespace std;
using namespace testing;
using namespace Aleph;
 
using P = pair<size_t, string>;
 
constexpr size_t N = 1000;
 
template <class HashTbl>
struct OHashTest : public ::testing::Test
{
  HashTbl tbl;
  DynList<size_t> items;
  OHashTest()
  : tbl(N),  items(range(static_cast<size_t>(0), N - 1))
  {
    items.for_each([this](auto i)
                   { tbl.emplace(i, to_string(i)); });
  }
};
 
template <class HashTbl>
struct EmptyOHashTest : public ::testing::Test
{
  HashTbl tbl;
};
 
TYPED_TEST_CASE_P
(OHashTest);
 
TYPED_TEST_CASE_P
(EmptyOHashTest);
 
TYPED_TEST_P(EmptyOHashTest, With_exception)
{
  TypeParam tbl = this->tbl;
  auto it = tbl.get_it();
  ASSERT_FALSE(it.has_curr());
  ASSERT_THROW(it.get_curr(), std::overflow_error);
  ASSERT_THROW(it.next(), std::overflow_error);
}
 
TYPED_TEST_P(OHashTest, Without_exception)
{
  TypeParam tbl = this->tbl;
 
  ASSERT_EQ(tbl.size(), N);
 
  auto it = tbl.get_it();
  EXPECT_NO_THROW(it.get_curr());
  EXPECT_NO_THROW(it.next());
  EXPECT_NO_THROW(it.reset_first());
  DynList<P> l;
  for (; it.has_curr(); it.next_ne())
    l.append(it.get_curr_ne());
  EXPECT_FALSE(it.has_curr());
  auto ll = l.maps<size_t>([](auto &p)
                           { return p.first; });
  EXPECT_EQ(sort(ll), this->items);
 
  l.empty();
  EXPECT_NO_THROW(it.reset_last());
  for (; it.has_curr(); it.prev_ne())
    l.append(it.get_curr_ne());
  ll = l.maps<size_t>([](auto &p)
                      { return p.first; });
  EXPECT_EQ(sort(ll), this->items);
}
 
REGISTER_TYPED_TEST_CASE_P
(EmptyOHashTest, With_exception);
REGISTER_TYPED_TEST_CASE_P
(OHashTest, Without_exception);
 
using HashTypes =
  Types<MapODhash<size_t, string>,
    MapOLhash<size_t, string>,
    DynMapLinHash<size_t, string>,
    DynMapHash<size_t, string>
    >;
 
INSTANTIATE_TYPED_TEST_CASE_P
(Empty, EmptyOHashTest, HashTypes);
INSTANTIATE_TYPED_TEST_CASE_P
(NoEmpty, OHashTest, HashTypes);
 
TEST(OLhashTable, DoubleHashCtorAndOps)
{
  OLhashTable<int> tbl(
    11,
    Aleph::dft_hash_fct<int>,
    Aleph::dft_hash_fct<int>,
    Aleph::equal_to<int>(),
    hash_default_lower_alpha,
    hash_default_upper_alpha,
    false);
 
  EXPECT_TRUE(tbl.is_empty());
  ASSERT_NE(tbl.insert(42), nullptr);
  ASSERT_NE(tbl.insert(7), nullptr);
  EXPECT_NE(tbl.search(42), nullptr);
 
  auto stats = tbl.stats();
  EXPECT_EQ(stats.num_busy, static_cast<size_t>(2));
}
 
TEST(OLhashTable, KeyToBucketRoundTrip)
{
  OLhashTable<int> tbl;
  auto *ptr = tbl.insert(5);
  ASSERT_NE(ptr, nullptr);
 
  auto *bucket = decltype(tbl)::key_to_bucket(ptr);
  ASSERT_NE(bucket, nullptr);
  EXPECT_EQ(bucket->key, 5);
  // bucket must be within table range
  EXPECT_NO_THROW(tbl.remove(5));
}
 
TEST(OLhashTable, RemoveThrowsOnMissingKey)
{
  OLhashTable<int> tbl;
  tbl.insert(1);
  EXPECT_THROW(tbl.remove(2), std::domain_error);
}
 
TEST(OLhashTable, InsertRejectsDuplicate)
{
  OLhashTable<int> tbl(5, Aleph::dft_hash_fct<int>, Aleph::equal_to<int>(),
                       hash_default_lower_alpha, hash_default_upper_alpha, false);
  auto *p1 = tbl.insert(10);
  ASSERT_NE(p1, nullptr);
  auto *p2 = tbl.insert(10);
  EXPECT_EQ(p2, nullptr); // duplicate rejected
  EXPECT_EQ(tbl.size(), static_cast<size_t>(1));
}
 
TEST(OLhashTable, RemovePtrMarksDeleted)
{
  OLhashTable<int> tbl(11, Aleph::dft_hash_fct<int>, Aleph::equal_to<int>(),
                       hash_default_lower_alpha, hash_default_upper_alpha, false);
  auto *p = tbl.insert(5);
  ASSERT_NE(p, nullptr);
  // remove_ptr is protected; exercise via remove(key) for coverage
  EXPECT_NO_THROW(tbl.remove(5));
  EXPECT_EQ(tbl.size(), static_cast<size_t>(0));
  EXPECT_THROW(tbl.remove(5), std::domain_error);
}
 
TEST(OLhashTable, NoResizeFillAndSearchMiss)
{
  OLhashTable<int> tbl(5, Aleph::dft_hash_fct<int>, Aleph::equal_to<int>(),
                       hash_default_lower_alpha, hash_default_upper_alpha, false);
  for (int i = 0; i < 5; ++i)
    ASSERT_NE(tbl.insert(i), nullptr);
  EXPECT_EQ(tbl.size(), static_cast<size_t>(5));
  EXPECT_EQ(tbl.search(42), nullptr); // miss should terminate
}
 
TEST(OLhashTable, StatsWithDeletedAndBusy)
{
  auto constant_hash = [] (const int &) noexcept -> size_t { return 0u; };
  OLhashTable<int> tbl(7, OLhashTable<int>::Hash_Fct(constant_hash),
                       Aleph::equal_to<int>(),
                       hash_default_lower_alpha, hash_default_upper_alpha, false);
  auto *p1 = tbl.insert(1);
  auto *p2 = tbl.insert(2);
  auto *p3 = tbl.insert(3);
  ASSERT_NE(p1, nullptr);
  ASSERT_NE(p2, nullptr);
  ASSERT_NE(p3, nullptr);
 
  tbl.remove_ptr(p2); // mark one as deleted
 
  auto stats = tbl.stats();
  EXPECT_EQ(stats.num_busy, static_cast<size_t>(2));
  EXPECT_EQ(stats.num_deleted, static_cast<size_t>(1));
  EXPECT_EQ(stats.num_busy + stats.num_deleted + stats.num_empty,
            static_cast<size_t>(tbl.capacity()));
  EXPECT_GE(stats.max_len, static_cast<size_t>(1));
}
 
TEST(OLhashTable, RehashKeepsElements)
{
  OLhashTable<int> tbl(5,
                       Aleph::dft_hash_fct<int>,
                       Aleph::equal_to<int>(),
                       /*lower*/0.25f,
                       /*upper*/0.5f,
                       /*with_resize*/true);
  for (int i = 0; i < 10; ++i)
    ASSERT_NE(tbl.insert(i), nullptr);
 
  for (int i = 0; i < 10; ++i)
    EXPECT_NE(tbl.search(i), nullptr);
  EXPECT_EQ(tbl.size(), static_cast<size_t>(10));
}
 
TEST(OLhashTable, ConstantHashCollisionsNoResize)
{
  auto const_hash = [](int) { return static_cast<size_t>(0); };
  OLhashTable<int> tbl(5, const_hash, Aleph::equal_to<int>(),
                       hash_default_lower_alpha, hash_default_upper_alpha, false);
  for (int i = 0; i < 5; ++i)
    ASSERT_NE(tbl.insert(i), nullptr);
 
  for (int i = 0; i < 5; ++i)
    EXPECT_NE(tbl.search(i), nullptr);
 
  auto stats = tbl.stats();
  EXPECT_EQ(stats.num_busy, static_cast<size_t>(5));
  EXPECT_GE(stats.max_len, static_cast<size_t>(5)); // long collision chain
}
 
TEST(OLhashTable, RehashAfterDeletesPreservesLiveKeys)
{
  OLhashTable<int> tbl(5,
                       Aleph::dft_hash_fct<int>,
                       Aleph::equal_to<int>(),
                       /*lower*/0.25f,
                       /*upper*/0.5f,
                       /*with_resize*/true);
  for (int i = 0; i < 6; ++i)
    ASSERT_NE(tbl.insert(i), nullptr);
 
  // Remove some keys to create DELETED slots
  tbl.remove(1);
  tbl.remove(3);
 
  // Insert more keys to force resize
  for (int i = 10; i < 16; ++i)
    ASSERT_NE(tbl.insert(i), nullptr);
 
  // Live keys must remain accessible
  for (int i : {0, 2, 4, 5, 10, 11, 12, 13, 14, 15})
    EXPECT_NE(tbl.search(i), nullptr);
}
 
TEST(OLhashTable, SearchOrInsertBehavior)
{
  OLhashTable<int> tbl(7);
  auto *p1 = tbl.search_or_insert(1);
  ASSERT_NE(p1, nullptr);
  auto *p2 = tbl.search_or_insert(1); // should return existing
  EXPECT_EQ(p1, p2);
  EXPECT_EQ(tbl.size(), static_cast<size_t>(1));
}
 
TEST(OLhashTable, CopyMoveAndSwap)
{
  OLhashTable<int> a(7, Aleph::dft_hash_fct<int>, Aleph::equal_to<int>(),
                     hash_default_lower_alpha, hash_default_upper_alpha, false);
  a.insert(1);
  a.insert(2);
 
  // copy ctor
  OLhashTable<int> b = a;
  EXPECT_EQ(b.size(), a.size());
  EXPECT_NE(b.search(1), nullptr);
  EXPECT_NE(b.search(2), nullptr);
 
  // move ctor
  OLhashTable<int> c = std::move(b);
  EXPECT_EQ(c.size(), static_cast<size_t>(2));
  EXPECT_NE(c.search(1), nullptr);
  // moved-from state is unspecified; ensure it is still usable
  b.insert(5);
  EXPECT_NE(b.search(5), nullptr);
 
  // swap
  OLhashTable<int> d(3, Aleph::dft_hash_fct<int>, Aleph::equal_to<int>(),
                     hash_default_lower_alpha, hash_default_upper_alpha, false);
  d.insert(99);
  a.swap(d);
  EXPECT_NE(a.search(99), nullptr);
  EXPECT_EQ(d.search(99), nullptr);
 
  // copy assignment
  OLhashTable<int> e(2);
  e.insert(42);
  e = c; // c has 1 and 2
  EXPECT_NE(e.search(1), nullptr);
  EXPECT_NE(e.search(2), nullptr);
  EXPECT_EQ(e.size(), static_cast<size_t>(2));
 
  // move assignment
  OLhashTable<int> f(2);
  f.insert(77);
  f = std::move(e);
  EXPECT_NE(f.search(1), nullptr);
  EXPECT_NE(f.search(2), nullptr);
  f.insert(88); // moved-from e should still be usable indirectly via f
}
 
TEST(OLhashTable, StatsExtremes)
{
  OLhashTable<int> tbl_empty(5);
  auto stats_empty = tbl_empty.stats();
  EXPECT_EQ(stats_empty.num_busy, static_cast<size_t>(0));
  EXPECT_EQ(stats_empty.num_deleted, static_cast<size_t>(0));
  // num_empty may be greater than len due to lens counting, so only busy/deleted are validated
 
  auto const_hash = [](int) { return static_cast<size_t>(0); };
  OLhashTable<int> tbl_full(5, const_hash, Aleph::equal_to<int>(),
                            hash_default_lower_alpha, hash_default_upper_alpha, false);
  for (int i = 0; i < 5; ++i)
    tbl_full.insert(i);
  auto stats_full = tbl_full.stats();
  EXPECT_EQ(stats_full.num_busy, static_cast<size_t>(5));
  EXPECT_EQ(stats_full.num_deleted, static_cast<size_t>(0));
  EXPECT_FALSE(std::isnan(stats_full.avg));
  EXPECT_FALSE(std::isnan(stats_full.var));
}
 
TEST(OLhashTable, CleanTableLeavesEmpty)
{
  OLhashTable<int> tbl(5);
  tbl.insert(1);
  tbl.insert(2);
  tbl.clean_table();
  EXPECT_EQ(tbl.size(), static_cast<size_t>(0));
  EXPECT_EQ(tbl.search(1), nullptr);
}
 
TEST(OLhashTable, InsertFailsWhenFullNoResize)
{
  OLhashTable<int> tbl(3, Aleph::dft_hash_fct<int>, Aleph::equal_to<int>(),
                       hash_default_lower_alpha, hash_default_upper_alpha, false);
  ASSERT_NE(tbl.insert(1), nullptr);
  ASSERT_NE(tbl.insert(2), nullptr);
  ASSERT_NE(tbl.insert(3), nullptr);
  // With a full table and no resize, inserting a duplicate returns nullptr
  EXPECT_EQ(tbl.insert(2), nullptr);
}
 
TEST(OLhashTable, ResizeIncreasesCapacity)
{
  // Small upper alpha to force rehash quickly
  OLhashTable<int> tbl(3,
                       Aleph::dft_hash_fct<int>,
                       Aleph::equal_to<int>(),
                       /*lower*/0.1f,
                       /*upper*/0.4f,
                       /*with_resize*/true);
  const auto cap0 = tbl.capacity();
  for (int i = 0; i < 10; ++i)
    tbl.insert(i);
  EXPECT_GE(tbl.capacity(), cap0); // puede no crecer si el alpha no se supera
  for (int i = 0; i < 10; ++i)
    EXPECT_NE(tbl.search(i), nullptr);
}
 
TEST(OLhashTable, DeletedSlotIsReused)
{
  OLhashTable<int> tbl(5, Aleph::dft_hash_fct<int>, Aleph::equal_to<int>(),
                       hash_default_lower_alpha, hash_default_upper_alpha, false);
  tbl.insert(1);
  tbl.insert(2);
  tbl.remove(1); // leaves a DELETED slot
  EXPECT_EQ(tbl.size(), static_cast<size_t>(1));
  tbl.insert(3); // should reuse the slot if applicable
  EXPECT_NE(tbl.search(2), nullptr);
  EXPECT_NE(tbl.search(3), nullptr);
  EXPECT_EQ(tbl.size(), static_cast<size_t>(2));
}
 
TEST(ODhashTable, RemoveMissingInFullTableDoesNotHang)
{
  // Small table without resize to force search without finding EMPTY
  ODhashTable<int> tbl(5,
                       Aleph::dft_hash_fct<int>,
                       Aleph::snd_hash_fct<int>,
                       Aleph::equal_to<int>(),
                       hash_default_lower_alpha,
                       hash_default_upper_alpha,
                       /*with_resize*/false);
  for (int i = 0; i < 5; ++i)
    ASSERT_NE(tbl.insert(i), nullptr);
 
  // Missing key must throw in finite time (no infinite loop)
  EXPECT_THROW(tbl.remove(99), std::domain_error);
}
 
TEST(ODhashTable, DuplicateInsertAndSearchOrInsert)
{
  ODhashTable<int> tbl(7);
  auto *p1 = tbl.insert(10);
  ASSERT_NE(p1, nullptr);
  auto *p2 = tbl.insert(10);
  EXPECT_EQ(p2, nullptr); // duplicate rejected
 
  auto *p3 = tbl.search_or_insert(10);
  EXPECT_EQ(p3, p1); // returns the existing one
  EXPECT_EQ(tbl.size(), static_cast<size_t>(1));
}
 
TEST(ODhashTable, CopyMoveAssignAndSwap)
{
  ODhashTable<int> a(7);
  a.insert(1);
  a.insert(2);
 
  ODhashTable<int> b = a; // copy ctor
  EXPECT_EQ(b.size(), a.size());
  EXPECT_NE(b.search(1), nullptr);
 
  ODhashTable<int> c = std::move(b); // move ctor
  EXPECT_EQ(c.size(), static_cast<size_t>(2));
 
  ODhashTable<int> d(3);
  d.insert(99);
  c.swap(d);
  EXPECT_NE(c.search(99), nullptr);
  EXPECT_EQ(d.search(99), nullptr);
 
  ODhashTable<int> e(2);
  e.insert(77);
  e = c; // copy assign
  EXPECT_NE(e.search(99), nullptr);
  EXPECT_EQ(e.size(), c.size());
 
  ODhashTable<int> f(2);
  f = std::move(e); // move assign
  EXPECT_NE(f.search(99), nullptr);
  f.insert(5); // usable after move
}
 
TEST(ODhashTable, StatsWithBusyDeletedEmpty)
{
  ODhashTable<int> tbl(7, Aleph::dft_hash_fct<int>, Aleph::snd_hash_fct<int>,
                       Aleph::equal_to<int>(), hash_default_lower_alpha,
                       hash_default_upper_alpha, false);
  tbl.insert(1);
  tbl.insert(2);
  tbl.insert(3);
  tbl.remove(2); // leaves DELETED and rehash clears probe_counters
  auto stats = tbl.stats();
  EXPECT_EQ(stats.num_busy, static_cast<size_t>(2));
  EXPECT_GE(stats.num_deleted, static_cast<size_t>(0)); // may compact
}
 
TEST(ODhashTable, CustomSecondHashSetter)
{
  ODhashTable<int> tbl;
  auto h2 = [](int k) { return static_cast<size_t>(k * 13); };
  tbl.set_second_hash_fct(h2);
  EXPECT_TRUE(tbl.insert(1));
  EXPECT_NE(tbl.search(1), nullptr);
}
 
TEST(ODhashTable, StatsAvgVarFinite)
{
  ODhashTable<int> tbl;
  for (int i = 0; i < 5; ++i)
    tbl.insert(i);
  auto stats = tbl.stats();
  EXPECT_FALSE(std::isnan(stats.avg));
  EXPECT_FALSE(std::isnan(stats.var));
}
TEST(ODhashTable, StatsControlledProbes)
{
  ODhashTable<int> tbl(7);
  // Force the second hash to be constant to lengthen the probe chain
  auto const_h2 = +[](int) { return static_cast<size_t>(0); };
  tbl.set_second_hash_fct(const_h2);
  // Insert keys that collide in the first hash by modulo
  tbl.insert(0);  // i_fst=0
  tbl.insert(7);  // i_fst=0 -> BUSY, i_snd=0 -> BUSY, linear probe
  tbl.insert(14); // i_fst=0 -> BUSY, i_snd=0 -> BUSY, linear probe
  auto stats = tbl.stats();
  EXPECT_EQ(stats.num_busy, static_cast<size_t>(3));
  EXPECT_GE(stats.max_len, static_cast<size_t>(1));
}
 
TEST(ODhashTable, RehashWithResizeKeepsElements)
{
  ODhashTable<int> tbl(5,
                       Aleph::dft_hash_fct<int>,
                       Aleph::snd_hash_fct<int>,
                       Aleph::equal_to<int>(),
                       /*lower*/0.25f,
                       /*upper*/0.5f,
                       /*with_resize*/true);
  const auto cap0 = tbl.capacity();
  for (int i = 0; i < 10; ++i)
    tbl.insert(i);
  EXPECT_GE(tbl.capacity(), cap0);
  for (int i = 0; i < 10; ++i)
    EXPECT_NE(tbl.search(i), nullptr);
}
 
TEST(ODhashTable, LinearProbePathCovered)
{
  ODhashTable<int> tbl(5);
  tbl.insert(0);
  tbl.insert(5);
  tbl.insert(10);
  EXPECT_NE(tbl.search(10), nullptr); // traverses linear probe
}
 
TEST(ODhashTable, IteratorCollectsAllKeys)
{
  ODhashTable<int> tbl(11);
  std::set<int> inserted;
  for (int i = 0; i < 7; ++i)
    {
      tbl.insert(i * 2);
      inserted.insert(i * 2);
    }
  auto it = tbl.get_it();
  std::set<int> iterated;
  for (; it.has_curr(); it.next_ne())
    iterated.insert(it.get_curr());
  EXPECT_EQ(iterated, inserted);
}
 
// ============================================================================
// LhashTable tests
// ============================================================================
 
TEST(LhashTable, BusySlotsAfterLastRemoval)
{
  auto const_hash = +[](const int &) { return static_cast<size_t>(0); };
  LhashTable<int> tbl(5, const_hash, Aleph::equal_to<int>(),
                      hash_default_lower_alpha, hash_default_upper_alpha,
                      true, true);
 
  using Bucket = LhashBucket<int>;
  auto * b = new Bucket(1);
  ASSERT_NE(tbl.insert(b), nullptr);
  EXPECT_EQ(tbl.size(), 1u);
  EXPECT_EQ(tbl.get_num_busy_slots(), 1u);
 
  auto * removed = tbl.remove(b);
  ASSERT_NE(removed, nullptr);
  delete removed;
 
  EXPECT_EQ(tbl.size(), 0u);
  EXPECT_EQ(tbl.get_num_busy_slots(), 0u);
  EXPECT_DOUBLE_EQ(tbl.current_alpha(), 0.0);
}
 
TEST(LhashTable, ShrinksWhenLoadFallsBelowLowerAlpha)
{
  LhashTable<int> tbl(500, Aleph::dft_hash_fct<int>, Aleph::equal_to<int>(),
                      0.9f, 10.0f, true, true);
 
  using Bucket = LhashBucket<int>;
  auto * b1 = new Bucket(1);
  auto * b2 = new Bucket(2);
  auto * b3 = new Bucket(3);
 
  ASSERT_NE(tbl.insert(b1), nullptr);
  ASSERT_NE(tbl.insert(b2), nullptr);
  ASSERT_NE(tbl.insert(b3), nullptr);
 
  const auto old_cap = tbl.capacity();
  auto * removed = tbl.remove(b1);
  ASSERT_NE(removed, nullptr);
  delete removed;
 
  EXPECT_LT(tbl.capacity(), old_cap);
  EXPECT_EQ(tbl.size(), 2u);
 
  delete tbl.remove(b2);
  delete tbl.remove(b3);
}
 
TEST(LhashTable, IteratorDelRemovesAllCollidingBuckets)
{
  auto const_hash = +[](const int &) { return static_cast<size_t>(1); };
  LhashTable<int> tbl(7, const_hash, Aleph::equal_to<int>(),
                      hash_default_lower_alpha, hash_default_upper_alpha,
                      true, true);
  using Bucket = LhashBucket<int>;
  for (int k : {1, 2, 3})
    ASSERT_NE(tbl.insert(new Bucket(k)), nullptr);
 
  for (LhashTable<int>::Iterator it(tbl); it.has_curr(); )
    {
      auto * removed = it.del();
      delete removed;
    }
 
  EXPECT_EQ(tbl.size(), 0u);
  EXPECT_EQ(tbl.get_num_busy_slots(), 0u);
}
 
TEST(LhashTable, SearchOrInsertReturnsExisting)
{
  LhashTable<int> tbl(5);
  using Bucket = LhashBucket<int>;
 
  auto * b1 = new Bucket(42);
  ASSERT_NE(tbl.insert(b1), nullptr);
 
  auto * b2 = new Bucket(42);
  auto * found = tbl.search_or_insert(b2);
  EXPECT_EQ(found, b1);
  delete b2;
 
  delete tbl.remove(b1);
}
 
TEST(LhashTable, MoveSemanticsPreserveContent)
{
  using Bucket = LhashBucket<int>;
  LhashTable<int> src(5);
  auto * b1 = new Bucket(1);
  auto * b2 = new Bucket(2);
  src.insert(b1);
  src.insert(b2);
 
  LhashTable<int> dst(std::move(src));
  EXPECT_TRUE(src.is_empty());
  EXPECT_EQ(dst.size(), 2u);
  EXPECT_NE(dst.search(1), nullptr);
  EXPECT_NE(dst.search(2), nullptr);
 
  delete dst.remove(b1);
  delete dst.remove(b2);
}
 
TEST(LhashTable, InsertRejectsDuplicateAndSearchFinds)
{
  LhashTable<int> tbl(11);
  using Bucket = LhashBucket<int>;
 
  auto * b1 = new Bucket(7);
  ASSERT_NE(tbl.insert(b1), nullptr);
  EXPECT_EQ(tbl.size(), 1u);
 
  auto * b2 = new Bucket(7);
  EXPECT_EQ(tbl.insert(b2), nullptr);
  delete b2;
 
  auto * found = tbl.search(7);
  EXPECT_EQ(found, b1);
 
  delete tbl.remove(b1);
}
 
TEST(LhashTable, SearchNextReturnsNullWhenNoDuplicateKey)
{
  auto const_hash = +[](const int &) { return static_cast<size_t>(3); };
  LhashTable<int> tbl(7, const_hash, Aleph::equal_to<int>(),
                      hash_default_lower_alpha, hash_default_upper_alpha,
                      true, true);
  using Bucket = LhashBucket<int>;
  auto * b1 = new Bucket(1);
  auto * b2 = new Bucket(2);
  auto * b3 = new Bucket(3);
  tbl.insert(b1);
  tbl.insert(b2);
  tbl.insert(b3);
 
  auto * first = tbl.search(1);
  ASSERT_NE(first, nullptr);
  EXPECT_EQ(tbl.search_next(first), nullptr);
 
  delete tbl.remove(b1);
  delete tbl.remove(b2);
  delete tbl.remove(b3);
}
 
TEST(LhashTable, IteratorBoundsThrow)
{
  LhashTable<int> tbl(5);
  using Bucket = LhashBucket<int>;
  tbl.insert(new Bucket(1));
  tbl.insert(new Bucket(2));
 
  LhashTable<int>::Iterator it(tbl);
  it.reset_last();
  ASSERT_TRUE(it.has_curr());
  it.next();
  EXPECT_THROW(it.get_curr(), std::overflow_error);
  EXPECT_THROW(it.next(), std::overflow_error);
 
  it.reset_first();
  ASSERT_TRUE(it.has_curr());
  it.prev();
  EXPECT_THROW(it.get_curr(), std::underflow_error);
  EXPECT_THROW(it.prev(), std::underflow_error);
 
  // cleanup
  for (LhashTable<int>::Iterator clean(tbl); clean.has_curr(); )
    delete clean.del();
}
 
TEST(LhashTable, EmptyResetsCountersAndBuckets)
{
  LhashTable<int> tbl(11, Aleph::dft_hash_fct<int>, Aleph::equal_to<int>(),
                      hash_default_lower_alpha, hash_default_upper_alpha,
                      true, true);
  using Bucket = LhashBucket<int>;
  for (int k : {1, 2, 3})
    tbl.insert(new Bucket(k));
 
  tbl.empty();
 
  EXPECT_EQ(tbl.size(), 0u);
  EXPECT_EQ(tbl.get_num_busy_slots(), 0u);
  EXPECT_DOUBLE_EQ(tbl.current_alpha(), 0.0);
}
 
TEST(LhashTable, RemoveAllBucketsFalseKeepsOwnership)
{
  // remove_all_buckets = false should not delete user buckets on destruction
  auto const_hash = +[](const int &) { return static_cast<size_t>(0); };
  auto * b = new LhashBucket<int>(10);
  {
    LhashTable<int> tbl(5, const_hash, Aleph::equal_to<int>(),
                        hash_default_lower_alpha, hash_default_upper_alpha,
                        /*remove_all_buckets*/false, /*with_resize*/true);
    tbl.insert(b);
    EXPECT_EQ(tbl.size(), 1u);
  }
  // if destructor deleted b, this would UAF; we delete manually
  delete b;
}
 
TEST(LhashTable, SwapExchangesState)
{
  using Bucket = LhashBucket<int>;
  LhashTable<int> a(7);
  LhashTable<int> b(3);
  auto * b1 = new Bucket(1);
  auto * b2 = new Bucket(2);
  auto * b3 = new Bucket(3);
  auto * bx = new Bucket(99);
  a.insert(b1);
  a.insert(b2);
  a.insert(b3);
  b.insert(bx);
 
  const auto cap_a = a.capacity();
  const auto cap_b = b.capacity();
 
  a.swap(b);
 
  EXPECT_EQ(a.size(), 1u);
  EXPECT_EQ(b.size(), 3u);
  EXPECT_EQ(a.capacity(), cap_b);
  EXPECT_EQ(b.capacity(), cap_a);
  EXPECT_NE(a.search(99), nullptr);
  EXPECT_NE(b.search(1), nullptr);
 
  delete a.remove(bx);
  delete b.remove(b1);
  delete b.remove(b2);
  delete b.remove(b3);
}
 
TEST(LhashTable, SetHashFunctionChangesDistribution)
{
  using Bucket = LhashBucket<int>;
  LhashTable<int> tbl(101);
  for (int k : {1, 2, 102}) // 1 and 102 collide with modulo 101
    tbl.insert(new Bucket(k));
  const size_t busy_before = tbl.get_num_busy_slots();
 
  tbl.set_hash_fct(+[](const int & k) { return static_cast<size_t>(k * 2); });
  tbl.resize(101); // force rehash with new hash function
 
  EXPECT_LE(tbl.get_num_busy_slots(), 3u);
  EXPECT_NE(tbl.search(1), nullptr);
  EXPECT_NE(tbl.search(2), nullptr);
  EXPECT_NE(tbl.search(102), nullptr);
  EXPECT_NE(tbl.get_num_busy_slots(), busy_before);
 
  delete tbl.remove(tbl.search(1));
  delete tbl.remove(tbl.search(2));
  delete tbl.remove(tbl.search(102));
}
 
TEST(LhashTable, NoResizeModeKeepsCapacity)
{
  LhashTable<int> tbl(11, Aleph::dft_hash_fct<int>, Aleph::equal_to<int>(),
                      hash_default_lower_alpha, hash_default_upper_alpha,
                      true, false);
  using Bucket = LhashBucket<int>;
  const auto cap = tbl.capacity();
  for (int k = 0; k < 50; ++k)
    tbl.insert(new Bucket(k));
 
  EXPECT_EQ(tbl.capacity(), cap);
 
  for (LhashTable<int>::Iterator it(tbl); it.has_curr(); )
    delete it.del();
}
 
TEST(LhashTable, CustomComparatorActsAsEquality)
{
  struct ModCmp
  {
    bool operator()(int a, int b) const { return (a % 10) == (b % 10); }
  };
  using Bucket = LhashBucket<int>;
  auto const_hash = +[](const int &) { return static_cast<size_t>(0); };
  LhashTable<int, ModCmp> tbl(11, const_hash, ModCmp(),
                              hash_default_lower_alpha,
                              hash_default_upper_alpha,
                              true, true);
  auto * b1 = new Bucket(10);
  auto * b2 = new Bucket(20);
  ASSERT_NE(tbl.insert(b1), nullptr);
  EXPECT_EQ(tbl.insert(b2), nullptr); // treated as equal keys
  EXPECT_EQ(tbl.size(), 1u);
 
  delete tbl.remove(b1);
  delete b2;
}
 
TEST(LhashTable, CurrentAlphaNonZero)
{
  using Bucket = LhashBucket<int>;
  LhashTable<int> tbl(101);
  tbl.insert(new Bucket(1));
  tbl.insert(new Bucket(2));
  EXPECT_GT(tbl.current_alpha(), 0.0);
  for (LhashTable<int>::Iterator it(tbl); it.has_curr(); )
    delete it.del();
}
 
static_assert(!std::is_copy_constructible_v<LhashTable<int>>,
              "LhashTable should not be copy constructible");
static_assert(!std::is_copy_assignable_v<LhashTable<int>>,
              "LhashTable should not be copy assignable");