From ca2091a884b47e2bafdb5eba80cf0bf7e9881799 Mon Sep 17 00:00:00 2001
From: Alexander Grund <Flamefire@users.noreply.github.com>
Date: Mon, 6 Jan 2020 09:41:47 +0100
Subject: [PATCH] Add BOOST_NOWIDE_FALLTHROUGH for Boost < 1.64

---
 include/boost/nowide/config.hpp     |  7 +++++++
 include/boost/nowide/detail/utf.hpp | 10 +++++-----
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/include/boost/nowide/config.hpp b/include/boost/nowide/config.hpp
index 40db464..63de44d 100644
--- a/include/boost/nowide/config.hpp
+++ b/include/boost/nowide/config.hpp
@@ -13,6 +13,7 @@
 
 #include <boost/config.hpp>
 #include <boost/nowide/replacement.hpp>
+#include <boost/version.hpp>
 
 #if defined(BOOST_ALL_DYN_LINK) || defined(BOOST_NOWIDE_DYN_LINK)
 #ifdef BOOST_NOWIDE_SOURCE
@@ -63,5 +64,11 @@
 #define BOOST_NOWIDE_USE_FSTREAM_REPLACEMENTS 0
 #endif
 
+#if BOOST_VERSION < 106500 && defined(BOOST_GCC) && BOOST_GCC_VERSION >= 70000
+#define BOOST_NOWIDE_FALLTHROUGH __attribute__((fallthrough))
+#else
+#define BOOST_NOWIDE_FALLTHROUGH BOOST_FALLTHROUGH
+#endif
+
 #endif // boost/nowide/config.hpp
 // vim: tabstop=4 expandtab shiftwidth=4 softtabstop=4
diff --git a/include/boost/nowide/detail/utf.hpp b/include/boost/nowide/detail/utf.hpp
index 28bd7f0..ed43980 100644
--- a/include/boost/nowide/detail/utf.hpp
+++ b/include/boost/nowide/detail/utf.hpp
@@ -8,7 +8,7 @@
 #ifndef BOOST_NOWIDE_UTF_HPP_INCLUDED
 #define BOOST_NOWIDE_UTF_HPP_INCLUDED
 
-#include <boost/config.hpp>
+#include <boost/nowide/config.hpp>
 #include <boost/cstdint.hpp>
 
 namespace boost {
@@ -219,7 +219,7 @@ namespace nowide {
                         if(!is_trail(tmp))
                             return illegal;
                         c = (c << 6) | (tmp & 0x3F);
-                        BOOST_FALLTHROUGH;
+                        BOOST_NOWIDE_FALLTHROUGH;
                     case 2:
                         if(BOOST_UNLIKELY(p == e))
                             return incomplete;
@@ -227,7 +227,7 @@ namespace nowide {
                         if(!is_trail(tmp))
                             return illegal;
                         c = (c << 6) | (tmp & 0x3F);
-                        BOOST_FALLTHROUGH;
+                        BOOST_NOWIDE_FALLTHROUGH;
                     case 1:
                         if(BOOST_UNLIKELY(p == e))
                             return incomplete;
@@ -269,8 +269,8 @@ namespace nowide {
 
                     switch(trail_size)
                     {
-                    case 3: c = (c << 6) | (static_cast<unsigned char>(*p++) & 0x3F); BOOST_FALLTHROUGH;
-                    case 2: c = (c << 6) | (static_cast<unsigned char>(*p++) & 0x3F); BOOST_FALLTHROUGH;
+                    case 3: c = (c << 6) | (static_cast<unsigned char>(*p++) & 0x3F); BOOST_NOWIDE_FALLTHROUGH;
+                    case 2: c = (c << 6) | (static_cast<unsigned char>(*p++) & 0x3F); BOOST_NOWIDE_FALLTHROUGH;
                     case 1: c = (c << 6) | (static_cast<unsigned char>(*p++) & 0x3F);
                     }