vpid: Provide is_empty

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

diff --git a/src/vpid.rs b/src/vpid.rs
index eff21b3c4a76f5216c931303f8c743d0bc7d2af4..e4f9e971e8948d7643d577a3a191e8520bffbc9f 100644 (file)
--- a/src/vpid.rs
+++ b/src/vpid.rs
@@ -154,6 +154,8 @@ impl Notches {
     }
   }
 
+  pub fn is_empty(&self) -> bool { self.used == 0 }
+
   #[cfg(test)]
   fn check(&self) {
     let mut count_free = 0;