deduplicate better_to_rebuild

Author: lengyijun

src/double_priority_queue/mod.rs

@@ -34,8 +34,9 @@ pub mod iterators;
 #[cfg(not(feature = "std"))]
 use std::vec::Vec;
 
+use crate::better_to_rebuild;
 use crate::core_iterators::*;
-use crate::store::{left, level, log2_fast, parent, right};
+use crate::store::{left, level, parent, right};
 use crate::store::{Index, Position, Store};
 use crate::TryReserveError;
 use iterators::*;
@@ -1219,21 +1220,6 @@ where
     }
 }
 
-// `rebuild` takes O(len1 + len2) operations
-// and about 2 * (len1 + len2) comparisons in the worst case
-// while `extend` takes O(len2 * log_2(len1)) operations
-// and about 1 * len2 * log_2(len1) comparisons in the worst case,
-// assuming len1 >= len2.
-fn better_to_rebuild(len1: usize, len2: usize) -> bool {
-    // log(1) == 0, so the inequation always falsy
-    // log(0) is inapplicable and produces panic
-    if len1 <= 1 {
-        return false;
-    }
-
-    2 * (len1 + len2) < len2 * log2_fast(len1)
-}
-
 #[cfg(feature = "serde")]
 #[cfg_attr(docsrs, doc(cfg(feature = "serde")))]
 mod serde {

src/lib.rs

@@ -119,6 +119,7 @@ mod store;
 
 pub use crate::double_priority_queue::DoublePriorityQueue;
 pub use crate::priority_queue::PriorityQueue;
+use crate::store::log2_fast;
 
 use indexmap::TryReserveError as IndexMapTryReserveError;
 use std::collections::TryReserveError as StdTryReserveError;
@@ -161,3 +162,18 @@ impl From<IndexMapTryReserveError> for TryReserveError {
         }
     }
 }
+
+// `rebuild` takes O(len1 + len2) operations
+// and about 2 * (len1 + len2) comparisons in the worst case
+// while `extend` takes O(len2 * log_2(len1)) operations
+// and about 1 * len2 * log_2(len1) comparisons in the worst case,
+// assuming len1 >= len2.
+fn better_to_rebuild(len1: usize, len2: usize) -> bool {
+    // log(1) == 0, so the inequation always falsy
+    // log(0) is inapplicable and produces panic
+    if len1 <= 1 {
+        return false;
+    }
+
+    2 * (len1 + len2) < len2 * log2_fast(len1)
+}

src/priority_queue/mod.rs

@@ -35,8 +35,9 @@ pub mod iterators;
 #[cfg(not(feature = "std"))]
 use std::vec::Vec;
 
+use crate::better_to_rebuild;
 use crate::core_iterators::*;
-use crate::store::{left, log2_fast, parent, right};
+use crate::store::{left, parent, right};
 use crate::store::{Index, Position, Store};
 use crate::TryReserveError;
 use iterators::*;
@@ -978,21 +979,6 @@ where
     }
 }
 
-// `rebuild` takes O(len1 + len2) operations
-// and about 2 * (len1 + len2) comparisons in the worst case
-// while `extend` takes O(len2 * log_2(len1)) operations
-// and about 1 * len2 * log_2(len1) comparisons in the worst case,
-// assuming len1 >= len2.
-fn better_to_rebuild(len1: usize, len2: usize) -> bool {
-    // log(1) == 0, so the inequation always falsy
-    // log(0) is inapplicable and produces panic
-    if len1 <= 1 {
-        return false;
-    }
-
-    2 * (len1 + len2) < len2 * log2_fast(len1)
-}
-
 #[cfg(feature = "serde")]
 #[cfg_attr(docsrs, doc(cfg(feature = "serde")))]
 mod serde {