Add util.rs

src/lib.rs

@@ -19,6 +19,7 @@ mod table_collection;
 mod table_iterator;
 mod trees;
 pub mod types;
+mod util;
 
 // re-export fundamental constants that
 // we can't live without

src/util.rs

@@ -0,0 +1,58 @@
+pub(crate) fn metadata_like_are_equal(a: &Option<Vec<u8>>, b: &Option<Vec<u8>>) -> bool {
+    match a {
+        Some(x) => match b {
+            Some(y) => x == y,
+            None => false,
+        },
+        None => match b.is_none() {
+            true => true,
+            false => false,
+        },
+    }
+}
+
+pub(crate) fn f64_partial_cmp_equal(a: &f64, b: &f64) -> bool {
+    match a.partial_cmp(b) {
+        Some(std::cmp::Ordering::Equal) => true,
+        Some(std::cmp::Ordering::Less) => false,
+        Some(std::cmp::Ordering::Greater) => false,
+        None => false,
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::metadata_like_are_equal;
+
+    #[test]
+    fn compare_some_to_none() {
+        let v: Vec<u8> = vec![1, 2, 3];
+        assert!(!metadata_like_are_equal(&Some(v), &None));
+    }
+
+    #[test]
+    fn compare_none_to_some() {
+        let v: Vec<u8> = vec![1, 2, 3];
+        assert!(!metadata_like_are_equal(&None, &Some(v)));
+    }
+
+    #[test]
+    fn compare_none_to_none() {
+        assert!(metadata_like_are_equal(&None, &None));
+    }
+
+    #[test]
+    fn compare_some_to_some_are_equal() {
+        let v: Vec<u8> = vec![1, 2, 3];
+        let vc = v.clone();
+        assert!(metadata_like_are_equal(&Some(v), &Some(vc)));
+    }
+
+    #[test]
+    fn compare_some_to_some_are_not_equal() {
+        let v: Vec<u8> = vec![1, 2, 3];
+        let mut vc = v.clone();
+        vc.push(11);
+        assert!(!metadata_like_are_equal(&Some(v), &Some(vc)));
+    }
+}