From cfeba45c35fff8e7afc083e566b817578a919c0a Mon Sep 17 00:00:00 2001
From: Victor Zverovich <victor.zverovich@gmail.com>
Date: Wed, 23 Apr 2014 18:37:49 -0700
Subject: [PATCH] Let the buffer grow as it pleases.

---
 format.cc | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/format.cc b/format.cc
index 671cc017..ab2a0ea3 100644
--- a/format.cc
+++ b/format.cc
@@ -360,7 +360,9 @@ void fmt::BasicWriter<Char>::FormatDouble(
       GrowBuffer(n);
       return;
     }
-    buffer_.reserve(n >= 0 ? offset + n + 1 : 2 * buffer_.capacity());
+    // If n is negative we ask to increase the capacity by at least 1,
+    // but as std::vector, the buffer grows exponentially.
+    buffer_.reserve(n >= 0 ? offset + n + 1 : buffer_.capacity() + 1);
   }
 }