Method addCodepointToCell

src/common/buffer/BufferLine.ts:230–254

* Add a codepoint to a cell from input handler. * During input stage combining chars with a width of 0 follow and stack * onto a leading char. Since we already set the attrs * by the previous `setDataFromCodePoint` call, we can omit it here.

(index: number, codePoint: number, width: number)

   * by the previous `setDataFromCodePoint` call, we can omit it here.
   */
  public addCodepointToCell(index: number, codePoint: number, width: number): void {
    let content = this._data[index * CELL_SIZE + Cell.CONTENT];
    if (content & Content.IS_COMBINED_MASK) {
      // we already have a combined string, simply add
      this._combined[index] += stringFromCodePoint(codePoint);
    } else {
      if (content & Content.CODEPOINT_MASK) {
        // normal case for combining chars:
        //  - move current leading char + new one into combined string
        //  - set combined flag
        this._combined[index] = stringFromCodePoint(content & Content.CODEPOINT_MASK) + stringFromCodePoint(codePoint);
        content &= ~Content.CODEPOINT_MASK; // set codepoint in buffer to 0
        content |= Content.IS_COMBINED_MASK;
      } else {
        // should not happen - we actually have no data in the cell yet
        // simply set the data in the cell buffer with a width of 1
        content = codePoint | (1 << Content.WIDTH_SHIFT);
      }
    }
    if (width) {
      content &= ~Content.WIDTH_MASK;
      content |= width << Content.WIDTH_SHIFT;
    }
    this._data[index * CELL_SIZE + Cell.CONTENT] = content;
  }

  public insertCells(pos: number, n: number, fillCellData: ICellData): void {
    pos %= this.length;