From f5e5d47fac0f654749c4d6267015005b74643dff Mon Sep 17 00:00:00 2001
From: abolz <lt.morris.schaffer@googlemail.com>
Date: Fri, 15 Jun 2018 11:29:48 +0200
Subject: [PATCH] Properly test for overflow

Do not use an approximation to do this. Instead check if the result is Inf.
---
 include/rapidjson/reader.h | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/include/rapidjson/reader.h b/include/rapidjson/reader.h
index f95aef4..69baef5 100644
--- a/include/rapidjson/reader.h
+++ b/include/rapidjson/reader.h
@@ -1561,8 +1561,6 @@ private:
         // Force double for big integer
         if (useDouble) {
             while (RAPIDJSON_LIKELY(s.Peek() >= '0' && s.Peek() <= '9')) {
-                if (RAPIDJSON_UNLIKELY(d >= 1.7976931348623157e307)) // DBL_MAX / 10.0
-                    RAPIDJSON_PARSE_ERROR(kParseErrorNumberTooBig, startOffset);
                 d = d * 10 + (s.TakePush() - '0');
             }
         }
@@ -1702,6 +1700,12 @@ private:
                else
                    d = internal::StrtodNormalPrecision(d, p);
 
+               if (d == std::numeric_limits<double>::infinity()) {
+                   // Overflow
+                   // TODO: internal::StrtodX should report overflow (or underflow)
+                   RAPIDJSON_PARSE_ERROR(kParseErrorNumberTooBig, startOffset);
+               }
+
                cont = handler.Double(minus ? -d : d);
            }
            else if (useNanOrInf) {