mcaptcha decrement by count

src/master/embedded/counter.rs

@@ -264,6 +264,18 @@ pub mod tests {
             .unwrap()
     }
 
+    #[test]
+    fn mcaptcha_decrement_by_works() {
+        let mut m = get_mcaptcha();
+        for _ in 0..100 {
+            m.add_visitor();
+        }
+        m.decrement_visitor_by(50);
+        assert_eq!(m.get_visitors(), 50);
+        m.decrement_visitor_by(500);
+        assert_eq!(m.get_visitors(), 0);
+    }
+
     #[actix_rt::test]
     async fn counter_defense_tightenup_works() {
         let addr: MyActor = get_counter().start();

src/mcaptcha.rs

@@ -98,6 +98,18 @@ impl MCaptcha {
         }
     }
 
+    /// decrements the visitor count by specified count
+    #[inline]
+    pub fn decrement_visitor_by(&mut self, count: u32) {
+        if self.visitor_threshold > 0 {
+            if self.visitor_threshold >= count {
+                self.visitor_threshold -= count;
+            } else {
+                self.visitor_threshold = 0;
+            }
+        }
+    }
+
     /// get current difficulty factor
     #[inline]
     pub fn get_difficulty(&self) -> u32 {