This short text is intended for the simdutf developers.

We use the following macros:

• SIMDUTF_FEATURE_BASE64
• SIMDUTF_FEATURE_UTF8
• SIMDUTF_FEATURE_UTF16
• SIMDUTF_FEATURE_UTF32
• SIMDUTF_FEATURE_ASCII
• SIMDUTF_FEATURE_LATIN1
• SIMDUTF_FEATURE_DETECT_ENCODING

The macros have by default value 1. Only during amalgamation their values can be altered to 0.

Technically, there are two constraints on SIMDUTF_FEATURE_XYZ flags:

• They must not be nested. Use logical operators for something more complex, like: ...UTF8 && (...UTF16 || ...UTF32).
• The corresponding endif must contain a repeated condition, of course commented out, like #endif // SIMDUTF_FEATURE_BASE64.

When we select given set of features, the API of library is reduced only to these features. It is the responsibility of users to detect whether they header having the expected set of features.

Making sure that selective amalgamation works as expected requires only a little work.

We assume that at least c++ command is available.

1. First of all, we need to execute ./test-features.py. It requires Python3.4, as we extensively use pathlib.
2. The script will detect what additional crosscompilers are available on the machine, and will generate Makefile using this information.
3. Finally run make Makefile, preferably with -j argument.

Our Makefile generates amalgamated library with different variants of features; the variants are predefined in test-features.py. Each feature set is compiled with all detected C++ compilers.

A sample test session looks like that:

$ ./test-features.py
Found the following crosscompilers in $PATH:
aarch64         : aarch64-linux-gnu-g++-14
powerpc64       : powerpc64-linux-gnu-g++
loongarch64     : loongarch64-linux-gnu-g++-14
loongarch64lasx : loongarch64-linux-gnu-g++-14
riscv64         : riscv64-linux-gnu-g++-14

$ make help
make all             --- build all targets
make clear           --- remove all generated files
make help            --- show this help

make default         --- build using c++
make aarch64         --- build using aarch64-linux-gnu-g++-14
make powerpc64       --- build using powerpc64-linux-gnu-g++
make loongarch64     --- build using loongarch64-linux-gnu-g++-14
make loongarch64lasx --- build using loongarch64-linux-gnu-g++-14
make riscv64         --- build using riscv64-linux-gnu-g++-14

$ make -j<some-sane-number>
...

Please do not commit Makefile, it's tailored for the machine where test-features.py was run.