yomichan/ext/bg/js/text-source-map.js

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2020-03-28 21:51:58 +00:00
/*
* Copyright (C) 2020 Yomichan Authors
2020-03-28 21:51:58 +00:00
*
* 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 <https://www.gnu.org/licenses/>.
*/
class TextSourceMap {
constructor(source, mapping=null) {
this._source = source;
this._mapping = (Array.isArray(mapping) ? TextSourceMap._normalizeMapping(mapping) : null);
}
get source() {
return this._source;
}
equals(other) {
if (this === other) {
return true;
}
const source = this._source;
if (!(other instanceof TextSourceMap && source === other._source)) {
return false;
}
let mapping = this._mapping;
let otherMapping = other._mapping;
if (mapping === null) {
if (otherMapping === null) {
return true;
}
mapping = TextSourceMap._createMapping(source);
} else if (otherMapping === null) {
otherMapping = TextSourceMap._createMapping(source);
}
const mappingLength = mapping.length;
if (mappingLength !== otherMapping.length) {
return false;
}
for (let i = 0; i < mappingLength; ++i) {
if (mapping[i] !== otherMapping[i]) {
return false;
}
}
return true;
}
getSourceLength(finalLength) {
const mapping = this._mapping;
if (mapping === null) {
return finalLength;
}
let sourceLength = 0;
for (let i = 0; i < finalLength; ++i) {
sourceLength += mapping[i];
}
return sourceLength;
}
combine(index, count) {
if (count <= 0) { return; }
if (this._mapping === null) {
this._mapping = TextSourceMap._createMapping(this._source);
}
let sum = this._mapping[index];
const parts = this._mapping.splice(index + 1, count);
for (const part of parts) {
sum += part;
}
this._mapping[index] = sum;
}
insert(index, ...items) {
if (this._mapping === null) {
this._mapping = TextSourceMap._createMapping(this._source);
}
this._mapping.splice(index, 0, ...items);
}
static _createMapping(text) {
return new Array(text.length).fill(1);
}
static _normalizeMapping(mapping) {
const result = [];
for (const value of mapping) {
result.push(
(typeof value === 'number' && Number.isFinite(value)) ?
Math.floor(value) :
0
);
}
return result;
}
}