yomichan/ext/mixed/js/japanese.js
2019-12-08 16:01:29 -05:00

178 lines
5.4 KiB
JavaScript

/*
* Copyright (C) 2016 Alex Yatskov <alex@foosoft.net>
* Author: Alex Yatskov <alex@foosoft.net>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
function jpIsKanji(c) {
const code = c.charCodeAt(0);
return code >= 0x4e00 && code < 0x9fb0 || code >= 0x3400 && code < 0x4dc0;
}
function jpIsKana(c) {
return wanakana.isKana(c);
}
function jpIsJapaneseText(text) {
for (const c of text) {
if (jpIsKanji(c) || jpIsKana(c)) {
return true;
}
}
return false;
}
function jpKatakanaToHiragana(text) {
let result = '';
for (const c of text) {
if (wanakana.isKatakana(c)) {
result += wanakana.toHiragana(c);
} else {
result += c;
}
}
return result;
}
function jpHiraganaToKatakana(text) {
let result = '';
for (const c of text) {
if (wanakana.isHiragana(c)) {
result += wanakana.toKatakana(c);
} else {
result += c;
}
}
return result;
}
function jpToRomaji(text) {
return wanakana.toRomaji(text);
}
function jpConvertReading(expressionFragment, readingFragment, readingMode) {
switch (readingMode) {
case 'hiragana':
return jpKatakanaToHiragana(readingFragment || '');
case 'katakana':
return jpHiraganaToKatakana(readingFragment || '');
case 'romaji':
if (readingFragment) {
return jpToRomaji(readingFragment);
} else {
if (jpIsKana(expressionFragment)) {
return jpToRomaji(expressionFragment);
}
}
return readingFragment;
default:
return readingFragment;
}
}
function jpDistributeFurigana(expression, reading) {
const fallback = [{furigana: reading, text: expression}];
if (!reading) {
return fallback;
}
let isAmbiguous = false;
const segmentize = (reading, groups) => {
if (groups.length === 0 || isAmbiguous) {
return [];
}
const group = groups[0];
if (group.mode === 'kana') {
if (jpKatakanaToHiragana(reading).startsWith(jpKatakanaToHiragana(group.text))) {
const readingLeft = reading.substring(group.text.length);
const segs = segmentize(readingLeft, groups.splice(1));
if (segs) {
return [{text: group.text}].concat(segs);
}
}
} else {
let foundSegments = null;
for (let i = reading.length; i >= group.text.length; --i) {
const readingUsed = reading.substring(0, i);
const readingLeft = reading.substring(i);
const segs = segmentize(readingLeft, groups.slice(1));
if (segs) {
if (foundSegments !== null) {
// more than one way to segmentize the tail, mark as ambiguous
isAmbiguous = true;
return null;
}
foundSegments = [{text: group.text, furigana: readingUsed}].concat(segs);
}
// there is only one way to segmentize the last non-kana group
if (groups.length === 1) {
break;
}
}
return foundSegments;
}
};
const groups = [];
let modePrev = null;
for (const c of expression) {
const modeCurr = jpIsKanji(c) || c.charCodeAt(0) === 0x3005 /* noma */ ? 'kanji' : 'kana';
if (modeCurr === modePrev) {
groups[groups.length - 1].text += c;
} else {
groups.push({mode: modeCurr, text: c});
modePrev = modeCurr;
}
}
const segments = segmentize(reading, groups);
if (segments && !isAmbiguous) {
return segments;
}
return fallback;
}
function jpDistributeFuriganaInflected(expression, reading, source) {
const output = [];
let stemLength = 0;
const shortest = Math.min(source.length, expression.length);
const sourceHiragana = jpKatakanaToHiragana(source);
const expressionHiragana = jpKatakanaToHiragana(expression);
while (stemLength < shortest && sourceHiragana[stemLength] === expressionHiragana[stemLength]) {
++stemLength;
}
const offset = source.length - stemLength;
const stemExpression = source.substring(0, source.length - offset);
const stemReading = reading.substring(
0,
offset === 0 ? reading.length : reading.length - expression.length + stemLength
);
for (const segment of jpDistributeFurigana(stemExpression, stemReading)) {
output.push(segment);
}
if (stemLength !== source.length) {
output.push({text: source.substring(stemLength)});
}
return output;
}