Class BufferLine

src/common/buffer/BufferLine.ts:61–551

 * memory allocs / GC pressure can be greatly reduced by reusing the CellData object.
 */
export class BufferLine implements IBufferLine {
  protected _data: Uint32Array;
  protected _combined: {[index: number]: string} = {};
  protected _extendedAttrs: {[index: number]: IExtendedAttrs | undefined} = {};
  public length: number;

  constructor(cols: number, fillCellData?: ICellData, public isWrapped: boolean = false) {
    this._data = new Uint32Array(cols * CELL_SIZE);
    const cell = fillCellData || CellData.fromCharData([0, NULL_CELL_CHAR, NULL_CELL_WIDTH, NULL_CELL_CODE]);
    for (let i = 0; i < cols; ++i) {
      this.setCell(i, cell);
    }
    this.length = cols;
  }

  /**
   * Get cell data CharData.
   * @deprecated
   */
  public get(index: number): CharData {
    const content = this._data[index * CELL_SIZE + Cell.CONTENT];
    const cp = content & Content.CODEPOINT_MASK;
    return [
      this._data[index * CELL_SIZE + Cell.FG],
      (content & Content.IS_COMBINED_MASK)
        ? this._combined[index]
        : (cp) ? stringFromCodePoint(cp) : '',
      content >> Content.WIDTH_SHIFT,
      (content & Content.IS_COMBINED_MASK)
        ? this._combined[index].charCodeAt(this._combined[index].length - 1)
        : cp
    ];
  }

  /**
   * Set cell data from CharData.
   * @deprecated
   */
  public set(index: number, value: CharData): void {
    this._data[index * CELL_SIZE + Cell.FG] = value[CHAR_DATA_ATTR_INDEX];
    if (value[CHAR_DATA_CHAR_INDEX].length > 1) {
      this._combined[index] = value[1];
      this._data[index * CELL_SIZE + Cell.CONTENT] = index | Content.IS_COMBINED_MASK | (value[CHAR_DATA_WIDTH_INDEX] << Content.WIDTH_SHIFT);
    } else {
      this._data[index * CELL_SIZE + Cell.CONTENT] = value[CHAR_DATA_CHAR_INDEX].charCodeAt(0) | (value[CHAR_DATA_WIDTH_INDEX] << Content.WIDTH_SHIFT);
    }
  }

  /**
   * primitive getters
   * use these when only one value is needed, otherwise use `loadCell`
   */
  public getWidth(index: number): number {
    return this._data[index * CELL_SIZE + Cell.CONTENT] >> Content.WIDTH_SHIFT;
  }

  /** Test whether content has width. */
  public hasWidth(index: number): number {