From 6caa9b6f95504c546f4ae10dfae6ed14a11fb2ad Mon Sep 17 00:00:00 2001
From: Bananymous <oskari.alaranta@bananymous.com>
Date: Thu, 7 Dec 2023 11:17:05 +0200
Subject: [PATCH] BAN: implement quick sort and test for it

---
 BAN/include/BAN/Sort.h       | 37 ++++++++++++++++++++++++++++++++++++
 userspace/test-sort/main.cpp |  4 ++++
 2 files changed, 41 insertions(+)

diff --git a/BAN/include/BAN/Sort.h b/BAN/include/BAN/Sort.h
index 4f1f6ab25d..e30e5fb50f 100644
--- a/BAN/include/BAN/Sort.h
+++ b/BAN/include/BAN/Sort.h
@@ -15,6 +15,43 @@ namespace BAN
 					swap(*lhs, *rhs);
 	}
 
+	namespace detail
+	{
 
+		template<typename It, typename Comp>
+		It sort_quick_partition(It begin, It end, Comp comp)
+		{
+			It pivot = end; --pivot;
+
+			It it1 = begin;
+			for (It it2 = begin; it2 != pivot; ++it2)
+			{
+				if (comp(*it2, *pivot))
+				{
+					swap(*it1, *it2);
+					++it1;
+				}
+			}
+
+			swap(*it1, *pivot);
+
+			return it1;
+		}
+
+	}
+
+	template<typename It, typename Comp = less<typename It::value_type>>
+	void sort_quick(It begin, It end, Comp comp = {})
+	{
+		{
+			It it = begin;
+			if (it == end || ++it == end)
+				return;
+		}
+
+		It mid = detail::sort_quick_partition(begin, end, comp);
+		sort_quick(begin, mid, comp);
+		sort_quick(++mid, end, comp);
+	}
 
 }
diff --git a/userspace/test-sort/main.cpp b/userspace/test-sort/main.cpp
index 0955f9942f..28d55faf18 100644
--- a/userspace/test-sort/main.cpp
+++ b/userspace/test-sort/main.cpp
@@ -34,4 +34,8 @@ int main()
 	TEST("exchange sort", BAN::sort_exchange, 100);
 	TEST("exchange sort", BAN::sort_exchange, 1000);
 	TEST("exchange sort", BAN::sort_exchange, 10000);
+
+	TEST("quick sort", BAN::sort_quick, 100);
+	TEST("quick sort", BAN::sort_quick, 1000);
+	TEST("quick sort", BAN::sort_quick, 10000);
 }