* Seek to position * 定位到指定位置
(indexTablePos: number, blockIndex: number)
| 78 | * 定位到指定位置 |
| 79 | */ |
| 80 | public seek(indexTablePos: number, blockIndex: number): boolean { |
| 81 | const tmp = this._position; |
| 82 | this._position = indexTablePos; |
| 83 | |
| 84 | const segCount = this.getUint8(); |
| 85 | if (blockIndex < segCount) { |
| 86 | const useShort = this.getUint8() === 1; |
| 87 | let newPos: number; |
| 88 | |
| 89 | if (useShort) { |
| 90 | this._position = indexTablePos + 2 + 2 * blockIndex; |
| 91 | newPos = this.getUint16(); |
| 92 | } else { |
| 93 | this._position = indexTablePos + 2 + 4 * blockIndex; |
| 94 | newPos = this.getUint32(); |
| 95 | } |
| 96 | |
| 97 | if (newPos > 0) { |
| 98 | this._position = indexTablePos + newPos; |
| 99 | return true; |
| 100 | } else { |
| 101 | this._position = tmp; |
| 102 | return false; |
| 103 | } |
| 104 | } else { |
| 105 | this._position = tmp; |
| 106 | return false; |
| 107 | } |
| 108 | } |
| 109 | |
| 110 | // Read methods | 读取方法 |
| 111 |