From e54f03f73ba6a2710fad457a299590ade22c3477 Mon Sep 17 00:00:00 2001
From: Matthew Bauer <mjbauer95@gmail.com>
Date: Thu, 2 Jul 2020 17:40:02 -0400
Subject: [PATCH 1/2] Tag binary values in cbor if set

CBOR has tags, which work similarly to "subtype"s:

https://www.iana.org/assignments/cbor-tags/cbor-tags.xhtml

Unsure if this makes sense. Note that the subtype must just be one
byte wide.
---
 include/nlohmann/detail/output/binary_writer.hpp | 6 ++++++
 single_include/nlohmann/json.hpp                 | 6 ++++++
 2 files changed, 12 insertions(+)

diff --git a/include/nlohmann/detail/output/binary_writer.hpp b/include/nlohmann/detail/output/binary_writer.hpp
index 3bac02270..580bc2e54 100644
--- a/include/nlohmann/detail/output/binary_writer.hpp
+++ b/include/nlohmann/detail/output/binary_writer.hpp
@@ -279,6 +279,12 @@ class binary_writer
 
             case value_t::binary:
             {
+                if (j.m_value.binary->has_subtype())
+                {
+                    write_number(static_cast<std::uint8_t>(0xd8));
+                    write_number(j.m_value.binary->subtype());
+                }
+
                 // step 1: write control byte and the binary array size
                 const auto N = j.m_value.binary->size();
                 if (N <= 0x17)
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index 7ab24c844..9269df1a2 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -12641,6 +12641,12 @@ class binary_writer
 
             case value_t::binary:
             {
+                if (j.m_value.binary->has_subtype())
+                {
+                    write_number(static_cast<std::uint8_t>(0xd8));
+                    write_number(j.m_value.binary->subtype());
+                }
+
                 // step 1: write control byte and the binary array size
                 const auto N = j.m_value.binary->size();
                 if (N <= 0x17)

From dd08f7705f621894a657aaef45ec73062c71398e Mon Sep 17 00:00:00 2001
From: Matthew Bauer <mjbauer95@gmail.com>
Date: Mon, 6 Jul 2020 18:06:10 -0400
Subject: [PATCH 2/2] Add simple test for cbor byte

---
 test/src/unit-cbor.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/test/src/unit-cbor.cpp b/test/src/unit-cbor.cpp
index b1c1a43e6..49dc72018 100644
--- a/test/src/unit-cbor.cpp
+++ b/test/src/unit-cbor.cpp
@@ -2503,6 +2503,8 @@ TEST_CASE("examples from RFC 7049 Appendix A")
         std::vector<uint8_t> expected((std::istreambuf_iterator<char>(f_bin)),
                                       std::istreambuf_iterator<char>());
         CHECK(j == json::binary(expected));
+
+        CHECK(json::to_cbor(json::binary(std::vector<uint8_t> {}, 0x42)) == std::vector<uint8_t> {0xd8, 0x42, 0x40});
     }
 
     SECTION("arrays")