builtin: a very early version of the hashmap

vlib/builtin/hashmap_test.v

@@ -0,0 +1,33 @@
+import rand
+import strings
+
+fn test_random_strings() {
+	mut m := new_hashmap(1000)
+	for i in 0..1000 {
+		mut buf := []byte
+		for j in 0..10 {
+			buf << byte(rand.next(int(`z`) - int(`a`)) + `a`)
+		}
+		s := string(buf)
+		//println(s)
+		m.set(s, i)
+		assert m.get(s) == i
+	}
+	m.set('foo', 12)
+	val := m.get('foo')
+	assert val == 12
+}	
+
+fn test_large_hashmap() {
+	N := 300 * 1000
+	mut nums := new_hashmap(N)
+	for i := 0; i < N; i++ {
+	        key := i.str()
+	        nums.set(key, i)
+	}
+	println('nr collisions: $nums.nr_collisions')
+	for i := 0; i < N; i++ {
+		key := i.str()
+		assert nums.get(key) == i
+	}
+}