From b8c7289c45d0e2fe2ba9b3ba7fab35e97fec973f Mon Sep 17 00:00:00 2001
From: Chris Cannam <cannam@all-day-breakfast.com>
Date: Tue, 7 Jun 2022 08:53:42 +0100
Subject: [PATCH] Further small improvement to moving median

---
 src/common/MovingMedian.h | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/common/MovingMedian.h b/src/common/MovingMedian.h
index 929fe3c..b574deb 100644
--- a/src/common/MovingMedian.h
+++ b/src/common/MovingMedian.h
@@ -110,7 +110,14 @@ private:
 	// postcondition: m_sorted contains m_size values, one of which is toPut
         // (and one instance of toDrop has been removed)
         int n = P::m_size;
-        int dropIx = std::lower_bound(m_sorted, m_sorted + n, toDrop) - m_sorted;
+        int dropIx;
+        if (toDrop <= m_sorted[0]) {
+            // this is quite a common short-circuit in situations
+            // where many values can be (the equivalent of) 0
+            dropIx = 0;
+        } else {
+            dropIx = std::lower_bound(m_sorted, m_sorted + n, toDrop) - m_sorted;
+        }
 
 #ifdef DEBUG_MM
         std::cout << "\nbefore: [";