From 33ea793020d57dc5d9ea981c649572b7d6d9d435 Mon Sep 17 00:00:00 2001
From: Nik Bougalis <nikb@bougalis.net>
Date: Thu, 19 Nov 2020 22:31:37 -0800
Subject: [PATCH] Avoid the need for floating point arithmetic

closes #2124
---
 CHANGELOG.md                                   |  1 +
 include/boost/beast/core/impl/multi_buffer.hpp | 14 ++++++++------
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 011f1f26..220923e2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,4 @@
+* Remove floating point arithmetic requirement.
 * Add `cxxstd` to json field.
 
 --------------------------------------------------------------------------------
diff --git a/include/boost/beast/core/impl/multi_buffer.hpp b/include/boost/beast/core/impl/multi_buffer.hpp
index 510d1265..8565b09f 100644
--- a/include/boost/beast/core/impl/multi_buffer.hpp
+++ b/include/boost/beast/core/impl/multi_buffer.hpp
@@ -912,15 +912,17 @@ prepare(size_type n) ->
         destroy(reuse);
         if(n > 0)
         {
-            auto const growth_factor = 2.0f;
+            std::size_t const growth_factor = 2;
+            std::size_t altn = in_size_ * growth_factor;
+	    // Overflow detection:
+            if(in_size_ > altn)
+                altn = std::numeric_limits<std::size_t>::max();
+            else
+                altn = (std::max<std::size_t>)(512, altn);
             auto const size =
                 (std::min<std::size_t>)(
                     max_ - total,
-                    (std::max<std::size_t>)({
-                        static_cast<std::size_t>(
-                            in_size_ * growth_factor - in_size_),
-                        512,
-                        n}));
+                    (std::max<std::size_t>)(n, altn));
             auto& e = alloc(size);
             list_.push_back(e);
             if(out_ == list_.end())