[rtsisyk]

Tarantool[1], a general-purpose database and app server based on LuaJIT, has Lua/C API to work with 64-bit numbers and even custom cdata objects [2]. I can extract this code into a separate library for you.

[1]: http://tarantool.org/ [2]: https://github.com/tarantool/tarantool/blob/1.7/src/lua/util...