From b0d7141c0c1c9dd872051d7b34ab8a99215e659d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ion=20Gazta=C3=B1aga?= <igaztanaga@gmail.com>
Date: Mon, 12 Jan 2026 23:04:42 +0100
Subject: [PATCH] Add compile time log2_pow2

---
 include/boost/container/detail/math_functions.hpp | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/include/boost/container/detail/math_functions.hpp b/include/boost/container/detail/math_functions.hpp
index e9a9165..af36896 100644
--- a/include/boost/container/detail/math_functions.hpp
+++ b/include/boost/container/detail/math_functions.hpp
@@ -167,6 +167,18 @@ struct lcm_ct
    BOOST_STATIC_CONSTEXPR std::size_t value = I1 * I2 / gcd_ct<I1, I2>::value;
 };
 
+template <std::size_t N, std::size_t Count = 0>
+struct log2_pow2
+{
+    BOOST_STATIC_CONSTEXPR std::size_t value = log2_pow2<(N >> 1), Count + 1>::value;
+};
+
+// Base case: we've reached 1
+template <std::size_t Count>
+struct log2_pow2<1, Count> {
+    BOOST_STATIC_CONSTEXPR std::size_t value = Count;
+};
+
 } // namespace dtl
 } // namespace container
 } // namespace boost