From 76842d637f312cb2bafcb63204a0f8ba2f6c5889 Mon Sep 17 00:00:00 2001
From: Damian Jarek <damian.jarek93@gmail.com>
Date: Mon, 3 Jun 2019 01:09:06 +0200
Subject: [PATCH] Reduce the number of instantiations of filter_token_list

Not using lambdas in this case reduced the number of instantiations of
the algorithm by a factor of 4x at no (observable) runtime cost.

Signed-off-by: Damian Jarek <damian.jarek93@gmail.com>
---
 CHANGELOG.md                             |  6 ++++
 include/boost/beast/http/impl/fields.hpp | 37 ++++++++++--------------
 2 files changed, 21 insertions(+), 22 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 29e47cbc..30b3a653 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+Version 259:
+
+* Reduce the number of instantiations of filter_token_list
+
+--------------------------------------------------------------------------------
+
 Version 258:
 
 * Fix separate compilation in CI
diff --git a/include/boost/beast/http/impl/fields.hpp b/include/boost/beast/http/impl/fields.hpp
index 9616af82..268f523d 100644
--- a/include/boost/beast/http/impl/fields.hpp
+++ b/include/boost/beast/http/impl/fields.hpp
@@ -824,16 +824,23 @@ keep_alive_impl(
     String& s, string_view value,
     unsigned version, bool keep_alive)
 {
+    struct iequals_predicate
+    {
+        bool operator()(string_view s)
+        {
+            return beast::iequals(s, sv1) || beast::iequals(s, sv2);
+        }
+
+        string_view sv1;
+        string_view sv2;
+    };
+
     if(version < 11)
     {
         if(keep_alive)
         {
             // remove close
-            filter_token_list(s, value,
-                [](string_view s)
-                {
-                    return iequals(s, "close");
-                });
+            filter_token_list(s, value, iequals_predicate{"close"});
             // add keep-alive
             if(s.empty())
                 s.append("keep-alive");
@@ -844,12 +851,7 @@ keep_alive_impl(
         {
             // remove close and keep-alive
             filter_token_list(s, value,
-                [](string_view s)
-                {
-                    return
-                        iequals(s, "close") ||
-                        iequals(s, "keep-alive");
-                });
+                iequals_predicate{"close", "keep-alive"});
         }
     }
     else
@@ -858,21 +860,12 @@ keep_alive_impl(
         {
             // remove close and keep-alive
             filter_token_list(s, value,
-                [](string_view s)
-                {
-                    return
-                        iequals(s, "close") ||
-                        iequals(s, "keep-alive");
-                });
+                iequals_predicate{"close", "keep-alive"});
         }
         else
         {
             // remove keep-alive
-            filter_token_list(s, value,
-                [](string_view s)
-                {
-                    return iequals(s, "keep-alive");
-                });
+            filter_token_list(s, value, iequals_predicate{"keep-alive"});
             // add close
             if(s.empty())
                 s.append("close");