From 5f62214ad5adcce6b8b34a8fd4afb6e8bb4715a4 Mon Sep 17 00:00:00 2001
From: Gennaro Prota <gennaro.prota@gmail.com>
Date: Thu, 18 Sep 2025 16:40:47 +0200
Subject: [PATCH] Make push_back() more efficient

---
 include/boost/dynamic_bitset/impl/dynamic_bitset.ipp | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/include/boost/dynamic_bitset/impl/dynamic_bitset.ipp b/include/boost/dynamic_bitset/impl/dynamic_bitset.ipp
index d2b5a4d..e7d2b8f 100644
--- a/include/boost/dynamic_bitset/impl/dynamic_bitset.ipp
+++ b/include/boost/dynamic_bitset/impl/dynamic_bitset.ipp
@@ -750,8 +750,13 @@ void
 dynamic_bitset< Block, AllocatorOrContainer >::
     push_back( bool bit )
 {
-    const size_type sz = size();
-    resize( sz + 1, bit );
+    const int extra_bits = count_extra_bits();
+    if ( extra_bits == 0 ) {
+        m_bits.push_back( Block( bit ) );
+    } else {
+        m_bits.back() |= ( Block( bit ) << extra_bits );
+    }
+    ++ m_num_bits;
 }
 
 template< typename Block, typename AllocatorOrContainer >