A faster C++ routine to convert 64 bit integers to ASCII form or std::string.
A Java implementation was created to be as algorithmically close as possible to the C++ code.
The initial code supports only 32-bit unsigned integers for simplicity and ease of comparison.
It also supports only direct writes to a ByteBuffer to avoid any allocation overhead.
Just include the source file fast_int_to_string.hpp into the translation unit.
In big data processing (e.g. columnar storage engines) even 10% improvement due to algorithmic/macro optimization results in cumulative effect (assuming other parts of the code is competitive enough). In my testing the conversion routine is 30-90% faster than standard counterparts.
Added few unit and performance tests.
The Java implementation has both unit tests and microbenchmarks. The initial code takes a bit more than twice as much time as built-in Java APIs for larger numbers. A collection of benchmark outcomes are stored in src/jmh/reports.
Please report.