From bb1c0a5eee4a31c1ded5b37c1e3a41fd7068b06c Mon Sep 17 00:00:00 2001
From: kd-11 <karokidii@gmail.com>
Date: Sun, 15 Jun 2025 22:04:57 +0300
Subject: [PATCH] rsx/util: Support basic array merge

---
 rpcs3/Emu/RSX/Common/simple_array.hpp |  7 +++++++
 rpcs3/tests/test_simple_array.cpp     | 25 +++++++++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/rpcs3/Emu/RSX/Common/simple_array.hpp b/rpcs3/Emu/RSX/Common/simple_array.hpp
index 06e0b1870d..033994547d 100644
--- a/rpcs3/Emu/RSX/Common/simple_array.hpp
+++ b/rpcs3/Emu/RSX/Common/simple_array.hpp
@@ -285,6 +285,13 @@ namespace rsx
 			return pos;
 		}
 
+		void operator += (const rsx::simple_array<Ty>& that)
+		{
+			const auto old_size = _size;
+			resize(_size + that._size);
+			std::memcpy(data() + old_size, that.data(), that.size_bytes());
+		}
+
 		void clear()
 		{
 			_size = 0;
diff --git a/rpcs3/tests/test_simple_array.cpp b/rpcs3/tests/test_simple_array.cpp
index f64e01200e..916284a6cd 100644
--- a/rpcs3/tests/test_simple_array.cpp
+++ b/rpcs3/tests/test_simple_array.cpp
@@ -189,4 +189,29 @@ namespace rsx
 			EXPECT_EQ(arr[i], i + 1);
 		}
 	}
+
+	TEST(SimpleArray, Merge)
+	{
+		rsx::simple_array<int> arr{ 1 };
+		rsx::simple_array<int> arr2{ 2, 3, 4, 5, 6, 7, 8, 9 };
+		rsx::simple_array<int> arr3{ 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 };
+
+		// Check small vector optimization
+		EXPECT_TRUE(arr.is_local_storage());
+
+		// Small vector optimization holds after append
+		arr += arr2;
+		EXPECT_TRUE(arr.is_local_storage());
+
+		// Exceed the boundary and we move into dynamic alloc
+		arr += arr3;
+		EXPECT_FALSE(arr.is_local_storage());
+
+		// Verify contents
+		EXPECT_EQ(arr.size(), 30);
+		for (int i = 0; i < 30; ++i)
+		{
+			EXPECT_EQ(arr[i], i + 1);
+		}
+	}
 }