From 64dc9a4eff9205e91d883bf8de8d0463a7e793a2 Mon Sep 17 00:00:00 2001
From: Matt Borland <matt@mattborland.com>
Date: Fri, 2 Jun 2023 10:04:03 +0200
Subject: [PATCH] Add __float128 overload

---
 include/boost/charconv/to_chars.hpp |  5 +++++
 src/to_chars.cpp                    | 17 +++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/include/boost/charconv/to_chars.hpp b/include/boost/charconv/to_chars.hpp
index 467fc5c..ed71b6e 100644
--- a/include/boost/charconv/to_chars.hpp
+++ b/include/boost/charconv/to_chars.hpp
@@ -778,6 +778,11 @@ BOOST_CHARCONV_DECL to_chars_result to_chars(char* first, char* last, double val
 BOOST_CHARCONV_DECL to_chars_result to_chars(char* first, char* last, long double value,
                                              chars_format fmt = chars_format::general, int precision = -1 ) noexcept;
 
+#ifdef BOOST_HAS_FLOAT128
+BOOST_CHARCONV_DECL to_chars_result to_chars(char* first, char* last, __float128 value,
+                                             chars_format fmt = chars_format::general, int precision = -1 ) noexcept;
+#endif
+
 } // namespace charconv
 } // namespace boost
 
diff --git a/src/to_chars.cpp b/src/to_chars.cpp
index 355ef53..6df6f12 100644
--- a/src/to_chars.cpp
+++ b/src/to_chars.cpp
@@ -616,4 +616,21 @@ boost::charconv::to_chars_result boost::charconv::to_chars( char* first, char* l
 
 #endif
 
+#ifdef BOOST_HAS_FLOAT128
 
+boost::charconv::to_chars_result to_chars(char* first, char* last, __float128 value, boost::charconv::chars_format fmt, int precision) noexcept
+{
+    if (first > last)
+    {
+        return {last, std::errc::invalid_argument};
+    }
+
+    (void)fmt;
+    (void)precision;
+    const auto fd128 = boost::charconv::detail::ryu::float128_to_fd128(value);
+    const auto num_chars = boost::charconv::detail::ryu::generic_to_chars(fd128, first);
+
+    return { first + num_chars, std::errc() };
+}
+
+#endif