kakasi

kakasi is a Rust library to transliterate hiragana, katakana and kanji (Japanese text) into rōmaji (Latin/Roman alphabet).

It was ported from the pykakasi library which itself is a port of the original kakasi library written in C.

Usage

Transliterate:

let res = kakasi::convert("こんにちは世界!");
assert_eq!(res.hiragana, "こんにちはせかい!");
assert_eq!(res.romaji, "konnichiha sekai!");

Check if a string contains Japanese characters:

use kakasi::IsJapanese;

assert_eq!(kakasi::is_japanese("Abc"), IsJapanese::False);
assert_eq!(kakasi::is_japanese("日本"), IsJapanese::Maybe);
assert_eq!(kakasi::is_japanese("ラスト"), IsJapanese::True);

CLI

$ cargo install kakasi

## Convert to romaji
$ kakasi こんにちは世界!
konnichiha sekai!

## Convert to hiragana
$ kakasi -k こんにちは世界!
こんにちはせかい!

## Read from file
$ kakasi -f rust_article.txt

## Read from STDIN
$ echo "こんにちは世界!" | kakasi

Performance

CPU: AMD Ryzen 7 5700G

Text	Conversion time	Speed
Sentence (161 B)	7.0911 µs	22.70 MB/s
Rust wikipedia article (31705 B)	1.5055 ms	21.06 MB/s

CLI comparison

Time to convert a 100KB test file using the CLI:

Library	Time	Speed
kakasi (Rust)	7.4 ms	13.5 MB/s
kakasi (C)	33.5 ms	2.99 MB/s
pykakasi (Python)	810.6 ms	0.123 MB/s

Test commands:

CLI performance was measured with hyperfine.

hyperfine --warmup 3 'cat 100K.txt | kakasi-rs'
hyperfine --warmup 3 'cat 100K.txt | kakasi -i utf-8 -Ka -Ha -Ja -Sa -s'
hyperfine --warmup 3 'cat 100K.txt | python bin/kakasi -Ka -Ha -Ja -Sa -s'

License

kakasi is published under the GNU GPL-3.0 license.

The Kakasi dictionaries (Files: codegen/dict/kakasidict.utf8, codegen/dict/itajidict.utf8, codegen/dict/hepburn.utf8) were taken from the pykakasi project, published under the GNU GPL-3.0 license.

pykakasi

Copyright (C) 2010-2021 Hiroshi Miura and contributors(see AUTHORS)

The dictionaries originate from the kakasi project, published under the GNU GPL-2.0 license.

original kakasi

Copyright (C) 1992 1993 1994
Hironobu Takahashi (takahasi@tiny.or.jp),
Masahiko Sato (masahiko@sato.riec.tohoku.ac.jp),
Yukiyoshi Kameyama, Miki Inooka, Akihiko Sasaki, Dai Ando, Junichi Okukawa,
Katsushi Sato and Nobuhiro Yamagishi

For testing I included a copy of the Japanese Rust wikipedia article (tests/rust_article.txt). The article is published under the Creative Commons Attribution-ShareAlike License 3.0.