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-rw-r--r--ext/js/general/text-source-map.js118
1 files changed, 118 insertions, 0 deletions
diff --git a/ext/js/general/text-source-map.js b/ext/js/general/text-source-map.js
new file mode 100644
index 00000000..49b6d99f
--- /dev/null
+++ b/ext/js/general/text-source-map.js
@@ -0,0 +1,118 @@
+/*
+ * Copyright (C) 2020-2021 Yomichan Authors
+ *
+ * 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 = (mapping !== null ? 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.getMappingCopy();
+ 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);
+ }
+
+ getMappingCopy() {
+ return this._mapping !== null ? [...this._mapping] : null;
+ }
+
+ 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;
+ }
+}