krobelus / widecharwidth

public domain wcwidth implementation

widecharwidth is a Python script that outputs implementations of wcwidth(), by downloading and parsing the latest UnicodeData.txt, EastAsianWidth.txt, and emoji-data.txt. Currently it generates C++, JavaScript, and Rust code.

C++ Usage

You may directly copy and use the included widechar_width.h.

This header contains a single public function widechar_wcwidth(). This returns either a positive width value (1 or 2), or a negative value such as widechar_private_use. Note that there are several possible negative return values, to distinguish among different scenarios.

If you aren't sure how to handle negative return values, try this table:

return value	width
widechar_nonprint	0
widechar_combining	0
widechar_ambiguous	1
widechar_private_use	1
widechar_unassigned	0
widechar_non_character	0
widechar_widened_in_9	2 (or maybe 1, renderer dependent)

JavaScript usage

The JS file widechar_width.js contains the function widechar_wcwidth(). This behaves the same as the C++ version.

Rust usage

In Rust, use widechar_width.rs and match WcWidth::from_char(). Example:

match WcWidth::from_char(c) {
    WcWidth::One | WcWidth::Two => (), // width 1 or 2
    WcWidth::Combining => (),          // zero-width combiner
    WcWidth::NonPrint => (),           // non-printing
    ...
}

Regenerating the sources

To regenerate the generated sources, run make. This will download and parse the relevant files, and run tests.

License

widecharwidth and its output files are released into the public domain. They may be used for any purpose without requiring attribution, or under the CC0 license if public domain is not available. See included LICENSE.