libluna: Add a sort() function

libluna/CMakeLists.txt

@@ -5,6 +5,7 @@ file(GLOB HEADERS include/luna/*.h)
 set(FREESTANDING_SOURCES
     ${HEADERS}
     src/Format.cpp
+    src/Sort.cpp
     src/NumberParsing.cpp
     src/CString.cpp
     src/CPath.cpp

libluna/include/luna/Sort.h

@@ -0,0 +1,26 @@
+#pragma once
+#include <luna/Types.h>
+
+typedef int (*compar_t)(const void*, const void*);
+
+void c_quicksort(void* base, usize nmemb, usize size, compar_t compar);
+
+template <typename T> void sort(T* base, usize nmemb, int (*compar)(const T*, const T*))
+{
+    return c_quicksort(base, nmemb, sizeof(T), (compar_t)compar);
+}
+
+template <typename T> void sort(T* base, usize nmemb, compar_t compar)
+{
+    return c_quicksort(base, nmemb, sizeof(T), compar);
+}
+
+template <typename T> void sort(T* begin, T* end, int (*compar)(const T*, const T*))
+{
+    return c_quicksort(begin, end - begin, sizeof(T), (compar_t)compar);
+}
+
+template <typename T> void sort(T* begin, T* end, compar_t compar)
+{
+    return c_quicksort(begin, end - begin, sizeof(T), compar);
+}

libluna/src/Sort.cpp

@@ -0,0 +1,53 @@
+#include <luna/Alignment.h>
+#include <luna/Sort.h>
+
+static void swap_sized(void* ptr1, void* ptr2, usize size)
+{
+    char* x = (char*)ptr1;
+    char* y = (char*)ptr2;
+
+    while (size--)
+    {
+        char t = *x;
+        *x = *y;
+        *y = t;
+        x += 1;
+        y += 1;
+    }
+}
+
+static usize partition(void* base, usize start, usize end, usize size, compar_t compar)
+{
+    auto atindex = [&base, &size](usize index) { return offset_ptr(base, index * size); };
+
+    void* pivot = atindex(end);
+    usize i = (start - 1);
+
+    for (usize j = start; j <= end - 1; j++)
+    {
+        if (compar(atindex(j), pivot) < 0)
+        {
+            i++;
+            swap_sized(atindex(i), atindex(j), size);
+        }
+    }
+
+    swap_sized(atindex(i + 1), pivot, size);
+    return i + 1;
+}
+
+static void quicksort_impl(void* base, usize start, usize end, usize size, compar_t compar)
+{
+    if (start < end)
+    {
+        usize pivot = partition(base, start, end, size, compar);
+        if ((end - start) < 2) return;
+        quicksort_impl(base, start, pivot - 1, size, compar);
+        quicksort_impl(base, pivot + 1, end, size, compar);
+    }
+}
+
+void c_quicksort(void* base, usize nmemb, usize size, compar_t compar)
+{
+    quicksort_impl(base, 0, nmemb - 1, size, compar);
+}