[lmi-commits] [lmi] master f565b23 1/3: Resolve a clang complaint

[Greg Chicares]

branch: master
commit f565b23d5db38a850c6075b59d2aa9a76e7a4c9f
Author: Gregory W. Chicares <address@hidden>
Commit: Gregory W. Chicares <address@hidden>

    Resolve a clang complaint
---
 bourn_cast.hpp | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/bourn_cast.hpp b/bourn_cast.hpp
index 4453aa2..92d05b1 100644
--- a/bourn_cast.hpp
+++ b/bourn_cast.hpp
@@ -115,6 +115,25 @@ inline To bourn_cast(From from, std::false_type, 
std::true_type)
     return static_cast<To>(from);
 }
 
+namespace lmi
+{
+/// A constexpr replacement for std::ldexp().
+///
+/// See:
+///   https://lists.nongnu.org/archive/html/lmi/2017-09/msg00003.html
+/// et seqq.
+
+template<typename T>
+constexpr T ldexp(T t, int exp)
+{
+    for(int i = 0; i < exp; ++i)
+        {
+        t *= T(2);
+        }
+    return t;
+}
+} // namespace lmi
+
 /// Floating to integral.
 ///
 /// Integral max() must be one less than an integer power of two,
@@ -174,7 +193,7 @@ inline To bourn_cast(From from, std::true_type, 
std::false_type)
     using from_traits = std::numeric_limits<From>;
     static_assert(to_traits::is_integer && !from_traits::is_integer, "");
 
-    constexpr From limit = std::ldexp(From(1), to_traits::digits);
+    constexpr From limit = lmi::ldexp(From(1), to_traits::digits);
 
     constexpr bool is_twos_complement(~To(0) == -To(1));