/* Copyright 2016-2024 Michele Santullo
 * This file is part of "duckhandy".
 *
 * "duckhandy" is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * "duckhandy" is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with "duckhandy".  If not, see <http://www.gnu.org/licenses/>.
 */

#include "catch2/catch_test_macros.hpp"
#include "duckhandy/small_object_allocator.hpp"
#include <memory>

namespace {
static const void* g_alloc_last{nullptr};
static std::size_t g_alloc_count{0};

template <typename T>
struct TestAlloc {
	std::unique_ptr<T> operator()() {
		auto ret = std::make_unique<T>();
		g_alloc_last = ret.get();
		++g_alloc_count;
		return ret;
	}
};
} //unnamed namespace

TEST_CASE("Check SmallObjectAllocator", "[SmallObjectAllocator][containers][memory][allocators]") {
	dhandy::SmallObjectAllocator<int, TestAlloc> soa;
	CHECK(g_alloc_last == nullptr);
	CHECK(g_alloc_count == 0u);

	int* const int01 = soa.allocate(sizeof(int));
	const void* old_block = g_alloc_last;
	REQUIRE(int01 != nullptr);
	CHECK(g_alloc_last != nullptr);
	CHECK(g_alloc_count == 1);

	int* const int02 = soa.allocate(sizeof(int));
	REQUIRE(int02 != nullptr);
	CHECK(int01 != int02);
	CHECK(g_alloc_last == old_block);
	CHECK(g_alloc_count == 1);

	int* prev_int = int02;
	for (std::size_t z = 2; z < dhandy::SmallObjectAllocator<int, TestAlloc>::objects_per_block; ++z) {
		int* const new_int = soa.allocate(sizeof(int));
		REQUIRE(new_int != nullptr);
		CHECK(new_int != int01);
		CHECK(new_int != prev_int);
		prev_int = new_int;
		CHECK(g_alloc_last == old_block);
		CHECK(g_alloc_count == 1);
		CHECK(reinterpret_cast<std::uintptr_t>(new_int) % alignof(int) == 0);
	}

	int* const int03 = soa.allocate(sizeof(int));
	REQUIRE(int03 != nullptr);
	CHECK(int03 != int02);
	CHECK(int03 != int01);
	CHECK(g_alloc_last != old_block);
	old_block = g_alloc_last;
	CHECK(g_alloc_count == 2);

	soa.deallocate(int02, sizeof(int));
}