Add support for high-precision numbers in UBJSON encoding

[hahmadi]

Feature Request

UBJSON is designed to support mapping from any JSON value. For numeric values specifically, it has a high-precision numeric value to represent any number: http://ubjson.org/?page_id=422#numeric

Currently nlohmann::json does not support that data type so users have to use other binary serialization formats. However, none of the other supported formats are as flexible as UBJSON in representing JSON values and have other limitations.

Can you provide a small but working code example?

json j1 = 11111111111111111111ULL;
auto v = json::to_ubjson(j1);
json j2 = json::from_ubjson(v);

What is the expected behavior?

Support storing uint64 numbers as high-precision numbers: http://ubjson.org/?page_id=422#numeric

And what is the actual behavior instead?

integer number 11111111111111111111 cannot be represented by UBJSON as it does not fit int64

Which version of the library did you use?

• latest release version 3.7.3
• other release - please state the version: ___
• the develop branch

[nlohmann]

Thanks for reporting. I think serialization should be simple as we can rely on code from the JSON serializer for int-to-string conversion. The reverse (parsing) could be more challenging I shall have a look.

[nlohmann]

I opened a PR #2297 for this issue. Unfortunately, there is a SIGSEGV when running the tests with MSVC 2019. Any help on this would be greatly appreciated!

[hahmadi]

Thank you for the quick turnaround!