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/*
* Copyright (c) 2020, Sahan Fernando <sahan.h.fernando@gmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibTest/TestCase.h>
#include <AK/QuickSort.h>
#include <AK/Random.h>
#include <AK/String.h>
#include <AK/Vector.h>
#include <stdlib.h>
const size_t NUM_RUNS = 100;
struct SortableObject {
int m_key;
int m_payload;
};
static int compare_sortable_object(const void* a, const void* b)
{
const int key1 = static_cast<const SortableObject*>(a)->m_key;
const int key2 = static_cast<const SortableObject*>(b)->m_key;
if (key1 < key2) {
return -1;
} else if (key1 == key2) {
return 0;
} else {
return 1;
}
}
static int calc_payload_for_pos(size_t pos)
{
pos *= 231;
return pos ^ (pos << 8) ^ (pos << 16) ^ (pos << 24);
}
static void shuffle_vec(Vector<SortableObject>& test_objects)
{
for (size_t i = 0; i < test_objects.size() * 3; ++i) {
auto i1 = get_random_uniform(test_objects.size());
auto i2 = get_random_uniform(test_objects.size());
swap(test_objects[i1], test_objects[i2]);
}
}
TEST_CASE(quick_sort)
{
// Generate vector of SortableObjects in sorted order, with payloads determined by their sorted positions
Vector<SortableObject> test_objects;
for (auto i = 0; i < 1024; ++i) {
test_objects.append({ i * 137, calc_payload_for_pos(i) });
}
for (size_t i = 0; i < NUM_RUNS; i++) {
// Shuffle the vector, then sort it again
shuffle_vec(test_objects);
qsort(test_objects.data(), test_objects.size(), sizeof(SortableObject), compare_sortable_object);
// Check that the objects are sorted by key
for (auto i = 0u; i + 1 < test_objects.size(); ++i) {
const auto& key1 = test_objects[i].m_key;
const auto& key2 = test_objects[i + 1].m_key;
if (key1 > key2) {
FAIL(String::formatted("saw key {} before key {}\n", key1, key2));
}
}
// Check that the object's payloads have not been corrupted
for (auto i = 0u; i < test_objects.size(); ++i) {
const auto expected = calc_payload_for_pos(i);
const auto payload = test_objects[i].m_payload;
if (payload != expected) {
FAIL(String::formatted("Expected payload {} for pos {}, got payload {}", expected, i, payload));
}
}
}
}
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