From 0a1c24eb9fe47ac2639c5933793e89563af07727 Mon Sep 17 00:00:00 2001
From: Miguel Portilla <miguelportilla@pobros.com>
Date: Tue, 18 Oct 2016 16:23:23 -0400
Subject: [PATCH] Refactor read_size_helper

---
 CHANGELOG.md                                |  1 +
 include/beast/core/impl/basic_streambuf.ipp | 10 ++++++----
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 04315bbc..7e66e6d7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,6 +14,7 @@
 * Add headers_parser
 * Engaged invokable is destructible
 * Improve websocket example in README.md
+* Refactor read_size_helper
 
 API Changes:
 
diff --git a/include/beast/core/impl/basic_streambuf.ipp b/include/beast/core/impl/basic_streambuf.ipp
index c002af00..fb091496 100644
--- a/include/beast/core/impl/basic_streambuf.ipp
+++ b/include/beast/core/impl/basic_streambuf.ipp
@@ -856,10 +856,12 @@ read_size_helper(basic_streambuf<
     Allocator> const& streambuf, std::size_t max_size)
 {
     auto const avail = streambuf.capacity() - streambuf.size();
-    if(avail == 0)
-        return std::min(max_size,
-            std::max<std::size_t>(512, streambuf.alloc_size_));
-    return std::min(max_size, avail);
+    if (avail > 0)
+        return std::min(avail, max_size);
+    constexpr std::size_t low = 512;
+    if (streambuf.alloc_size_ > low)
+        return std::min(max_size, streambuf.alloc_size_);
+    return std::min(max_size, low);
 }
 
 template<class Alloc, class T>