flat_map_test.cc

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/*
                          Aleph_w
 
  Data structures & Algorithms
  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
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  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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*/
 
#include <iterator>
#include <map>
#include <random>
#include <stdexcept>
#include <string>
#include <utility>
#include <vector>
 
#include <gtest/gtest.h>
 
#include <tpl_flat_map.H>
 
using Aleph::FlatMap;
 
namespace
{
class Pair_Input_Iterator
{
  const std::vector<std::pair<int, std::string>> *items_ = nullptr;
  size_t pos_ = 0;
 
public:
 
  using iterator_category = std::input_iterator_tag;
  using value_type = std::pair<int, std::string>;
  using difference_type = std::ptrdiff_t;
  using pointer = void;
  using reference = const value_type &;
 
  Pair_Input_Iterator() = default;
 
  Pair_Input_Iterator(const std::vector<std::pair<int, std::string>> &items,
                      size_t pos) noexcept
    : items_(&items), pos_(pos) {}
 
  reference operator*() const noexcept { return (*items_)[pos_]; }
 
  Pair_Input_Iterator &operator++() noexcept
  {
    ++pos_;
    return *this;
  }
 
  Pair_Input_Iterator operator++(int) noexcept
  {
    Pair_Input_Iterator ret = *this;
    ++(*this);
    return ret;
  }
 
  bool operator==(const Pair_Input_Iterator &it) const noexcept
  {
    return items_ == it.items_ and pos_ == it.pos_;
  }
 
  bool operator!=(const Pair_Input_Iterator &it) const noexcept
  {
    return not (*this == it);
  }
};
}  // namespace
 
TEST(FlatMap, EmptyMapBasics)
{
  FlatMap<std::string, int> m;
  EXPECT_TRUE(m.is_empty());
  EXPECT_EQ(m.size(), 0u);
  EXPECT_FALSE(m.contains("x"));
  EXPECT_EQ(m.find("x"), m.end());
  EXPECT_EQ(m.begin(), m.end());
}
 
TEST(FlatMap, SubscriptInsertsAndUpdates)
{
  FlatMap<std::string, int> m;
  m["b"] = 2;
  m["a"] = 1;
  m["c"] = 3;
  ASSERT_EQ(m.size(), 3u);
 
  m["a"] += 10;  // update through subscript
  EXPECT_EQ(m.at("a"), 11);
 
  // Absent key gets a default-constructed value.
  EXPECT_EQ(m["zz"], 0);
  EXPECT_EQ(m.size(), 4u);
 
  // Keys must come out sorted.
  EXPECT_EQ(m.nth_key(0), "a");
  EXPECT_EQ(m.nth_key(1), "b");
  EXPECT_EQ(m.nth_key(2), "c");
  EXPECT_EQ(m.nth_key(3), "zz");
}
 
TEST(FlatMap, AtThrowsOnMissingKey)
{
  FlatMap<std::string, int> m = {{"a", 1}};
  EXPECT_EQ(m.at("a"), 1);
  EXPECT_THROW((void) m.at("nope"), std::out_of_range);
 
  const FlatMap<std::string, int> &cm = m;
  EXPECT_EQ(cm.at("a"), 1);
  EXPECT_THROW((void) cm.at("nope"), std::out_of_range);
}
 
TEST(FlatMap, InitializerListDropsDuplicateKeysFirstWins)
{
  FlatMap<int, std::string> m = {{3, "three"}, {1, "one"},
                                  {3, "THREE"}, {2, "two"}};
  ASSERT_EQ(m.size(), 3u);
  EXPECT_EQ(m.at(3), "three");  // first occurrence wins
  EXPECT_EQ(m.nth_key(0), 1);
  EXPECT_EQ(m.nth_key(2), 3);
}
 
TEST(FlatMap, RangeConstructorAcceptsIteratorsWithoutArrow)
{
  const std::vector<std::pair<int, std::string>> items =
    {{3, "three"}, {1, "one"}, {2, "two"}};
 
  FlatMap<int, std::string> m(Pair_Input_Iterator(items, 0),
                              Pair_Input_Iterator(items, items.size()));
 
  ASSERT_EQ(m.size(), 3u);
  EXPECT_EQ(m.at(1), "one");
  EXPECT_EQ(m.at(2), "two");
  EXPECT_EQ(m.at(3), "three");
}
 
// The map's own iterators yield a (key, value) proxy with no common
// reference with std::pair, so they do not model std::input_iterator; the
// range constructor must still accept them.
TEST(FlatMap, RangeConstructorAcceptsOwnIteratorAndConstIterator)
{
  FlatMap<int, std::string> src = {{2, "two"}, {1, "one"}, {3, "three"}};
  const FlatMap<int, std::string> &csrc = src;
 
  FlatMap<int, std::string> from_it(src.begin(), src.end());
  FlatMap<int, std::string> from_cit(csrc.begin(), csrc.end());
  FlatMap<int, std::string> from_tail(src.begin() + 1, src.end());
 
  EXPECT_EQ(from_it, src);
  EXPECT_EQ(from_cit, src);
  ASSERT_EQ(from_tail.size(), 2u);
  EXPECT_FALSE(from_tail.contains(1));
  EXPECT_EQ(from_tail.at(3), "three");
}
 
TEST(FlatMap, InsertRejectsDuplicateInsertOrAssignOverwrites)
{
  FlatMap<int, int> m;
  EXPECT_TRUE(m.insert(1, 100).second);
  EXPECT_FALSE(m.insert(1, 999).second);
  EXPECT_EQ(m.at(1), 100);  // original value kept
 
  EXPECT_FALSE(m.insert_or_assign(1, 999).second);
  EXPECT_EQ(m.at(1), 999);  // overwritten
 
  EXPECT_TRUE(m.insert_or_assign(2, 200).second);
  EXPECT_EQ(m.at(2), 200);
 
  // Pair-based insert.
  EXPECT_TRUE(m.insert(std::pair<int, int>(3, 300)).second);
  EXPECT_EQ(m.at(3), 300);
}
 
TEST(FlatMap, EraseByKeyAndIterator)
{
  FlatMap<int, int> m = {{1, 10}, {2, 20}, {3, 30}, {4, 40}};
 
  EXPECT_EQ(m.erase(2), 1u);
  EXPECT_EQ(m.erase(2), 0u);
  EXPECT_EQ(m.size(), 3u);
 
  auto it = m.find(3);
  ASSERT_NE(it, m.end());
  it = m.erase(it);
  EXPECT_EQ((*it).first, 4);  // entry following the erased one
  EXPECT_EQ(m.size(), 2u);
 
  EXPECT_THROW((void) m.erase(m.end()), std::out_of_range);
}
 
TEST(FlatMap, ProxyIterationAndStructuredBindings)
{
  FlatMap<std::string, int> m = {{"b", 2}, {"a", 1}, {"c", 3}};
 
  std::vector<std::string> ks;
  int sum = 0;
  for (auto [k, v] : m)
    {
      ks.push_back(k);
      sum += v;
    }
  EXPECT_EQ(ks, (std::vector<std::string>{"a", "b", "c"}));
  EXPECT_EQ(sum, 6);
 
  // Mutation through the iterator proxy.
  for (auto [k, v] : m)
    v *= 10;
  EXPECT_EQ(m.at("a"), 10);
  EXPECT_EQ(m.at("b"), 20);
  EXPECT_EQ(m.at("c"), 30);
 
  // Arrow access.
  auto it = m.find("b");
  ASSERT_NE(it, m.end());
  EXPECT_EQ(it->first, "b");
  it->second = 7;
  EXPECT_EQ(m.at("b"), 7);
}
 
TEST(FlatMap, IteratorRandomAccessOperations)
{
  FlatMap<int, int> m = {{1, 10}, {2, 20}, {3, 30}, {4, 40}};
 
  auto it = m.begin();
  EXPECT_EQ(m.end() - it, 4);
  EXPECT_EQ((it + 2)->first, 3);
  EXPECT_EQ(it[3].second, 40);
  ++it;
  --it;
  EXPECT_EQ(it->first, 1);
  EXPECT_TRUE(it < m.end());
 
  // Mutable-to-const iterator conversion.
  FlatMap<int, int>::const_iterator cit = m.begin();
  EXPECT_EQ(cit->second, 10);
}
 
TEST(FlatMap, BoundsAndEqualRange)
{
  const FlatMap<int, int> m = {{10, 1}, {20, 2}, {30, 3}};
 
  EXPECT_EQ(m.lower_bound(20)->first, 20);
  EXPECT_EQ(m.lower_bound(25)->first, 30);
  EXPECT_EQ(m.upper_bound(20)->first, 30);
  EXPECT_EQ(m.lower_bound(31), m.end());
 
  auto [lo, hi] = m.equal_range(20);
  EXPECT_EQ(hi - lo, 1);
  auto [lo2, hi2] = m.equal_range(15);
  EXPECT_EQ(lo2, hi2);
}
 
TEST(FlatMap, KeysAndValuesLists)
{
  FlatMap<std::string, int> m = {{"b", 2}, {"a", 1}, {"c", 3}};
 
  auto ks = m.keys();
  auto vs = m.values();
  ASSERT_EQ(ks.size(), 3u);
  ASSERT_EQ(vs.size(), 3u);
  EXPECT_EQ(ks.get_first(), "a");
  EXPECT_EQ(ks.get_last(), "c");
  EXPECT_EQ(vs.get_first(), 1);
  EXPECT_EQ(vs.get_last(), 3);
}
 
TEST(FlatMap, TraverseMutatingAndEarlyStop)
{
  FlatMap<int, int> m = {{1, 1}, {2, 2}, {3, 3}};
 
  EXPECT_TRUE(m.traverse([] (const int &, int &v) { v += 100; return true; }));
  EXPECT_EQ(m.at(1), 101);
 
  int visited = 0;
  const FlatMap<int, int> &cm = m;
  EXPECT_FALSE(cm.traverse([&visited] (const int &k, const int &)
  {
    ++visited;
    return k < 2;
  }));
  EXPECT_EQ(visited, 2);
}
 
TEST(FlatMap, CopyMoveEqualityAndSwap)
{
  FlatMap<std::string, int> m = {{"x", 1}, {"y", 2}};
  FlatMap<std::string, int> copy = m;
  EXPECT_EQ(copy, m);
 
  FlatMap<std::string, int> moved = std::move(copy);
  EXPECT_EQ(moved, m);
 
  moved["z"] = 3;
  EXPECT_NE(moved, m);
 
  FlatMap<std::string, int> other = {{"q", 9}};
  m.swap(other);
  EXPECT_EQ(m.size(), 1u);
  EXPECT_EQ(m.at("q"), 9);
  EXPECT_EQ(other.size(), 2u);
}
 
TEST(FlatMap, CustomComparatorDescendingOrder)
{
  FlatMap<int, std::string, std::greater<int>> m
    = {{1, "one"}, {5, "five"}, {3, "three"}};
  EXPECT_EQ(m.nth_key(0), 5);
  EXPECT_EQ(m.nth_key(1), 3);
  EXPECT_EQ(m.nth_key(2), 1);
  EXPECT_EQ(m.at(3), "three");
}
 
TEST(FlatMap, ParallelStorageAccessors)
{
  FlatMap<int, int> m = {{2, 20}, {1, 10}, {3, 30}};
  const int *kp = m.keys_data();
  const int *vp = m.values_data();
  for (size_t i = 0; i < m.size(); ++i)
    EXPECT_EQ(vp[i], kp[i] * 10);
}
 
// Randomized parity test: FlatMap must behave exactly like std::map under
// an arbitrary interleaving of subscripts, inserts, erases and lookups.
TEST(FlatMap, RandomizedParityWithStdMap)
{
  std::mt19937 rng(20260702);
  std::uniform_int_distribution<int> key_dist(0, 150);
  std::uniform_int_distribution<int> val_dist(0, 1000000);
  std::uniform_int_distribution<int> op_dist(0, 3);
 
  FlatMap<int, int> fm;
  std::map<int, int> ref;
 
  for (int step = 0; step < 4000; ++step)
    {
      const int k = key_dist(rng);
      const int v = val_dist(rng);
      switch (op_dist(rng))
        {
        case 0:
          fm[k] = v;
          ref[k] = v;
          break;
        case 1:
          EXPECT_EQ(fm.insert(k, v).second, ref.insert({k, v}).second);
          break;
        case 2:
          EXPECT_EQ(fm.erase(k), ref.erase(k));
          break;
        default:
          {
            const auto it = ref.find(k);
            if (it == ref.end())
              EXPECT_FALSE(fm.contains(k));
            else
              EXPECT_EQ(fm.at(k), it->second);
          }
          break;
        }
    }
 
  ASSERT_EQ(fm.size(), ref.size());
  size_t i = 0;
  for (const auto &[k, v] : ref)
    {
      EXPECT_EQ(fm.nth_key(i), k);
      EXPECT_EQ(fm.nth_value(i), v);
      ++i;
    }
}