base: add Array::Swap() method and the corresponding unit test.

src/lol/base/array.h

@@ -168,6 +168,21 @@ public:
         Remove(m_count - 1, 1);
     }
 
+    void Swap(int pos1, int pos2)
+    {
+        ASSERT(pos1 >= 0);
+        ASSERT(pos2 >= 0);
+        ASSERT(pos1 < m_count);
+        ASSERT(pos2 < m_count);
+
+        if (pos1 != pos2)
+        {
+            Element tmp = (*this)[pos1];
+            (*this)[pos1] = (*this)[pos2];
+            (*this)[pos2] = tmp;
+        }
+    }
+
     void Remove(int pos, int todelete = 1)
     {
         ASSERT(pos >= 0);

test/unit/array.cpp

@@ -100,6 +100,19 @@ LOLUNIT_FIXTURE(ArrayTest)
         LOLUNIT_ASSERT_EQUAL(a[0].m8, 0);
     }
 
+    LOLUNIT_TEST(ArraySwap)
+    {
+        Array<int, int> a;
+        a.Push(10, 20);
+        a.Push(30, 40);
+        a.Swap(0, 1);
+
+        LOLUNIT_ASSERT_EQUAL(30, a[0].m1);
+        LOLUNIT_ASSERT_EQUAL(40, a[0].m2);
+        LOLUNIT_ASSERT_EQUAL(10, a[1].m1);
+        LOLUNIT_ASSERT_EQUAL(20, a[1].m2);
+    }
+
     LOLUNIT_TEST(ArrayConcat)
     {
         Array<int> a, b;