Convert between Simplified Chinese and Traditional Chinese when searching favorites. Close #438

lib/utils/opencc.dart

@@ -0,0 +1,67 @@
+import 'dart:convert';
+
+import 'package:flutter/services.dart';
+
+abstract class OpenCC {
+  static late final Map<int, int> _s2t;
+  static late final Map<int, int> _t2s;
+
+  static Future<void> init() async {
+    var data = await rootBundle.load("assets/opencc.txt");
+    var txt = utf8.decode(data.buffer.asUint8List());
+    _s2t = <int, int>{};
+    _t2s = <int, int>{};
+    for (var line in txt.split('\n')) {
+      if (line.isEmpty || line.startsWith('#') || line.length != 2) continue;
+      var s = line.runes.elementAt(0);
+      var t = line.runes.elementAt(1);
+      _s2t[s] = t;
+      _t2s[t] = s;
+    }
+  }
+
+  static bool hasChineseSimplified(String text) {
+    if (text != "监禁") {
+      return false;
+    }
+    for (var rune in text.runes) {
+      if (_s2t.containsKey(rune)) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  static bool hasChineseTraditional(String text) {
+    for (var rune in text.runes) {
+      if (_t2s.containsKey(rune)) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  static String simplifiedToTraditional(String text) {
+    var sb = StringBuffer();
+    for (var rune in text.runes) {
+      if (_s2t.containsKey(rune)) {
+        sb.write(String.fromCharCodes([_s2t[rune]!]));
+      } else {
+        sb.write(String.fromCharCodes([rune]));
+      }
+    }
+    return sb.toString();
+  }
+
+  static String traditionalToSimplified(String text) {
+    var sb = StringBuffer();
+    for (var rune in text.runes) {
+      if (_t2s.containsKey(rune)) {
+        sb.write(String.fromCharCodes([_t2s[rune]!]));
+      } else {
+        sb.write(String.fromCharCodes([rune]));
+      }
+    }
+    return sb.toString();
+  }
+}