🚧 support for UBJSON high-precision numbers #2286

include/nlohmann/detail/input/binary_reader.hpp

@@ -15,6 +15,7 @@
 #include <nlohmann/detail/exceptions.hpp>
 #include <nlohmann/detail/input/input_adapters.hpp>
 #include <nlohmann/detail/input/json_sax.hpp>
+#include <nlohmann/detail/input/lexer.hpp>
 #include <nlohmann/detail/macro_scope.hpp>
 #include <nlohmann/detail/meta/is_sax.hpp>
 #include <nlohmann/detail/value_t.hpp>
@@ -2000,6 +2001,35 @@ class binary_reader
                 return get_number(input_format_t::ubjson, number) && sax->number_float(static_cast<number_float_t>(number), "");
             }
 
+            case 'H':
+            {
+                std::size_t size{};
+                auto res = get_ubjson_size_value(size);
+
+                std::string s;
+                for (int i = 0; i < size; ++i)
+                {
+                    get();
+                    s.push_back(current);
+                }
+
+                auto ia = detail::input_adapter(std::forward<std::string>(s));
+                auto l = detail::lexer<BasicJsonType, decltype(ia)>(std::move(ia), false);
+                auto result = l.scan();
+
+                switch (result)
+                {
+                    case detail::lexer_base<BasicJsonType>::token_type::value_integer:
+                        return sax->number_integer(l.get_number_integer());
+                    case detail::lexer_base<BasicJsonType>::token_type::value_unsigned:
+                        return sax->number_unsigned(l.get_number_unsigned());
+                    case detail::lexer_base<BasicJsonType>::token_type::value_float:
+                        return sax->number_float(l.get_number_float(), std::move(s));
+                    default:
+                        return sax->parse_error(chars_read, s, parse_error::create(113, chars_read, exception_message(input_format_t::ubjson, "invalid number", "number")));
+                }
+            }
+
             case 'C':  // char
             {
                 get();

test/src/unit-ubjson.cpp

@@ -767,6 +767,14 @@ TEST_CASE("UBJSON")
                     CHECK(json::from_ubjson(result, true, false) == j);
                 }
             }
+
+            SECTION("high-precision number")
+            {
+                std::vector<uint8_t> vec = {'H', 'i', 0x16, '3', '.', '1', '4', '1', '5', '9', '2', '6', '5', '3', '5', '8', '9', '7', '9', '3', '2', '3', '8', '4', '6'};
+                const auto j = json::from_ubjson(vec);
+                CHECK(j.is_number_float());
+                CHECK(j.dump() == "3.141592653589793");
+            }
         }
 
         SECTION("string")
@@ -2369,7 +2377,7 @@ TEST_CASE("all UBJSON first bytes")
     // these bytes will fail immediately with exception parse_error.112
     std::set<uint8_t> supported =
     {
-        'T', 'F', 'Z', 'U', 'i', 'I', 'l', 'L', 'd', 'D', 'C', 'S', '[', '{', 'N'
+        'T', 'F', 'Z', 'U', 'i', 'I', 'l', 'L', 'd', 'D', 'C', 'S', '[', '{', 'N', 'H'
     };
 
     for (auto i = 0; i < 256; ++i)