bf: add a module implementing operations with bit arrays (#1049)

vlib/bf/bf_test.v

@@ -0,0 +1,45 @@
+import bf
+
+import rand
+
+fn test_bf_new_size() {
+	instance := bf.new(5)
+	assert instance.getsize() == 5
+}
+
+fn test_bf_set_clear_toggle_get() {
+	mut instance := bf.new(5)
+	instance.setbit(4)
+	assert instance.getbit(4) == 1
+	instance.clearbit(4)
+	assert instance.getbit(4) == 0
+	instance.togglebit(4)
+	assert instance.getbit(4) == 1
+}
+
+fn test_bf_and_not_or_xor() {
+	rand.seed()
+	len := 80
+	mut input1 := bf.new(len)
+	mut input2 := bf.new(len)
+	mut i := 0
+	for i < len {
+		if rand.next(2) == 1 {
+			input1.setbit(i)
+		}
+		if rand.next(2) == 1{
+			input2.setbit(i)
+		}
+		i++
+	}
+	output1 := bf.bfxor(input1, input2)
+	bfand := bf.bfand(input1, input2)
+	bfor := bf.bfor(input1, input2)
+	bfnot := bf.bfnot(bfand)
+	output2 := bf.bfand(bfor, bfnot)
+	mut result := 1
+	for i < len {
+		if output1.getbit(i) != output2.getbit(i) {result = 0}
+	}
+	assert result == 1
+}