LibC: Replace Berkley's qsort() with AK::dual_pivot_quick_sort() wrapper

1 files changed, 98 insertions, 0 deletions

diff --git a/Tests/LibC/qsort-sorts-and-copies.cpp b/Tests/LibC/qsort-sorts-and-copies.cpp
new file mode 100644
index 0000000000..c7ded6a78a
--- /dev/null
+++ b/Tests/LibC/qsort-sorts-and-copies.cpp
@@ -0,0 +1,98 @@
+/*
+ * Copyright (c) 2020, Sahan Fernando <sahan.h.fernando@gmail.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <AK/QuickSort.h>
+#include <AK/String.h>
+#include <AK/Vector.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+const size_t NUM_RUNS = 100;
+
+struct SortableObject {
+    int m_key;
+    int m_payload;
+};
+
+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;
+    }
+}
+
+int calc_payload_for_pos(size_t pos) {
+    pos *= 231;
+    return pos ^ (pos << 8) ^ (pos << 16) ^ (pos << 24);
+}
+
+void shuffle_vec(Vector<SortableObject> &test_objects)
+{
+    for (size_t i = 0; i < test_objects.size() * 3; ++i) {
+        auto i1 = rand() % test_objects.size();
+        auto i2 = rand() % test_objects.size();
+        swap(test_objects[i1], test_objects[i2]);
+    }
+}
+
+int main()
+{
+    // 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) {
+                printf("\x1b[01;35mTests failed: saw key %d before key %d\n", key1, key2);
+                return 1;
+            }
+        }
+        // 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) {
+                printf("\x1b[01;35mTests failed: expected payload %d for pos %u, got payload %d\n", expected, i, payload);
+                return 1;
+            }
+        }
+    }
+    printf("Tests succeeded\n");
+    return 0;
+}