1 files changed, 102 insertions, 0 deletions
diff --git a/Userland/Libraries/LibC/qsort.cpp b/Userland/Libraries/LibC/qsort.cpp
new file mode 100644
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+++ b/Userland/Libraries/LibC/qsort.cpp
@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * 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/Assertions.h>
+#include <AK/QuickSort.h>
+#include <stdlib.h>
+#include <sys/types.h>
+
+class SizedObject {
+public:
+    SizedObject() = delete;
+    SizedObject(void* data, size_t size)
+        : m_data(data)
+        , m_size(size)
+    {
+    }
+    void* data() const { return m_data; }
+    size_t size() const { return m_size; }
+
+private:
+    void* m_data;
+    size_t m_size;
+};
+
+namespace AK {
+
+template<>
+inline void swap(const SizedObject& a, const SizedObject& b)
+{
+    ASSERT(a.size() == b.size());
+    const size_t size = a.size();
+    const auto a_data = reinterpret_cast<char*>(a.data());
+    const auto b_data = reinterpret_cast<char*>(b.data());
+    for (auto i = 0u; i < size; ++i) {
+        swap(a_data[i], b_data[i]);
+    }
+}
+
+}
+
+class SizedObjectSlice {
+public:
+    SizedObjectSlice() = delete;
+    SizedObjectSlice(void* data, size_t element_size)
+        : m_data(data)
+        , m_element_size(element_size)
+    {
+    }
+    const SizedObject operator[](size_t index)
+    {
+        return { static_cast<char*>(m_data) + index * m_element_size, m_element_size };
+    }
+
+private:
+    void* m_data;
+    size_t m_element_size;
+};
+
+void qsort(void* bot, size_t nmemb, size_t size, int (*compar)(const void*, const void*))
+{
+    if (nmemb <= 1) {
+        return;
+    }
+
+    SizedObjectSlice slice { bot, size };
+
+    AK::dual_pivot_quick_sort(slice, 0, nmemb - 1, [=](const SizedObject& a, const SizedObject& b) { return compar(a.data(), b.data()) < 0; });
+}
+
+void qsort_r(void* bot, size_t nmemb, size_t size, int (*compar)(const void*, const void*, void*), void* arg)
+{
+    if (nmemb <= 1) {
+        return;
+    }
+
+    SizedObjectSlice slice { bot, size };
+
+    AK::dual_pivot_quick_sort(slice, 0, nmemb - 1, [=](const SizedObject& a, const SizedObject& b) { return compar(a.data(), b.data(), arg) < 0; });
+}