Move charset into own service

src/common/services/CharsetService.ts

@@ -0,0 +1,33 @@
+/**
+ * Copyright (c) 2019 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+import { ICharsetService } from 'common/services/Services';
+import { ICharset } from 'common/Types';
+
+export class CharsetService implements ICharsetService {
+  serviceBrand: any;
+
+  public charset: ICharset | undefined;
+  public charsets: ICharset[] = [];
+  public glevel: number = 0;
+
+  public reset(): void {
+    this.charset = undefined;
+    this.charsets = [];
+    this.glevel = 0;
+  }
+
+  public setgLevel(g: number): void {
+    this.glevel = g;
+    this.charset = this.charsets[g];
+  }
+
+  public setgCharset(g: number, charset: ICharset): void {
+    this.charsets[g] = charset;
+    if (this.glevel === g) {
+      this.charset = charset;
+    }
+  }
+}