From e9990e1656df7fd4863fab819a6d67b3cf07964d Mon Sep 17 00:00:00 2001
From: TimTIM <i@timtim.hk>
Date: Thu, 28 Nov 2024 03:21:10 +0800
Subject: [PATCH] Serialize non-finite numbers as their corresponding JSON
 string representations.

---
 msgpackpp/include/msgpackpp/msgpackpp.h | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/msgpackpp/include/msgpackpp/msgpackpp.h b/msgpackpp/include/msgpackpp/msgpackpp.h
index 8200750..d5f5035 100644
--- a/msgpackpp/include/msgpackpp/msgpackpp.h
+++ b/msgpackpp/include/msgpackpp/msgpackpp.h
@@ -1186,7 +1186,19 @@ class parser {
           os << "false";
         }
       } else if (is_number()) {
-        os << get_number<double>();
+        const auto d = get_number<double>();
+        if (std::isfinite(d)) {
+          os << d;
+        } else {
+          // see https://learn.microsoft.com/dotnet/api/system.text.json.serialization.jsonnumberhandling
+          if (std::isnan(d)) {
+            os << "\"NaN\"";
+          } else if (d == std::numeric_limits<double>::infinity()) {
+            os << "\"Infinity\"";
+          } else if (d == -std::numeric_limits<double>::infinity()) {
+            os << "\"-Infinity\"";
+          }
+        }
       } else if (is_string()) {
         os << '"' << get_string() << '"';
       } else if (is_binary()) {