| 646 | * Use only in environments which do not offer native conversion methods! |
| 647 | */ |
| 648 | export function decodeUTF8(buffer: Uint8Array): string { |
| 649 | // https://en.wikipedia.org/wiki/UTF-8 |
| 650 | |
| 651 | const len = buffer.byteLength; |
| 652 | const result: string[] = []; |
| 653 | let offset = 0; |
| 654 | while (offset < len) { |
| 655 | const v0 = buffer[offset]; |
| 656 | let codePoint: number; |
| 657 | if (v0 >= 0b11110000 && offset + 3 < len) { |
| 658 | // 4 bytes |
| 659 | codePoint = ( |
| 660 | (((buffer[offset++] & 0b00000111) << 18) >>> 0) |
| 661 | | (((buffer[offset++] & 0b00111111) << 12) >>> 0) |
| 662 | | (((buffer[offset++] & 0b00111111) << 6) >>> 0) |
| 663 | | (((buffer[offset++] & 0b00111111) << 0) >>> 0) |
| 664 | ); |
| 665 | } else if (v0 >= 0b11100000 && offset + 2 < len) { |
| 666 | // 3 bytes |
| 667 | codePoint = ( |
| 668 | (((buffer[offset++] & 0b00001111) << 12) >>> 0) |
| 669 | | (((buffer[offset++] & 0b00111111) << 6) >>> 0) |
| 670 | | (((buffer[offset++] & 0b00111111) << 0) >>> 0) |
| 671 | ); |
| 672 | } else if (v0 >= 0b11000000 && offset + 1 < len) { |
| 673 | // 2 bytes |
| 674 | codePoint = ( |
| 675 | (((buffer[offset++] & 0b00011111) << 6) >>> 0) |
| 676 | | (((buffer[offset++] & 0b00111111) << 0) >>> 0) |
| 677 | ); |
| 678 | } else { |
| 679 | // 1 byte |
| 680 | codePoint = buffer[offset++]; |
| 681 | } |
| 682 | |
| 683 | if ((codePoint >= 0 && codePoint <= 0xD7FF) || (codePoint >= 0xE000 && codePoint <= 0xFFFF)) { |
| 684 | // Basic Multilingual Plane |
| 685 | result.push(String.fromCharCode(codePoint)); |
| 686 | } else if (codePoint >= 0x010000 && codePoint <= 0x10FFFF) { |
| 687 | // Supplementary Planes |
| 688 | const uPrime = codePoint - 0x10000; |
| 689 | const w1 = 0xD800 + ((uPrime & 0b11111111110000000000) >>> 10); |
| 690 | const w2 = 0xDC00 + ((uPrime & 0b00000000001111111111) >>> 0); |
| 691 | result.push(String.fromCharCode(w1)); |
| 692 | result.push(String.fromCharCode(w2)); |
| 693 | } else { |
| 694 | // illegal code point |
| 695 | result.push(String.fromCharCode(0xFFFD)); |
| 696 | } |
| 697 | } |
| 698 | |
| 699 | return result.join(''); |
| 700 | } |
| 701 | |
| 702 | /** |
| 703 | * Generated using https://github.com/alexandrudima/unicode-utils/blob/master/generate-rtl-test.js |