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- function con(n) {
- return 0x80 | (n & 0x3f);
- }
- export function encode(str) {
- const arr = str.split("").map((x) => x.charCodeAt(0));
- return _encode(arr);
- }
- function _encode(arr) {
- if (arr.length === 0) {
- return [];
- }
- const [n, ...ns] = arr;
- if (n < 0) {
- throw new Error("utf8");
- }
- if (n < 0x80) {
- return [n, ..._encode(ns)];
- }
- if (n < 0x800) {
- return [0xc0 | (n >>> 6), con(n), ..._encode(ns)];
- }
- if (n < 0x10000) {
- return [0xe0 | (n >>> 12), con(n >>> 6), con(n), ..._encode(ns)];
- }
- if (n < 0x110000) {
- return [
- 0xf0 | (n >>> 18),
- con(n >>> 12),
- con(n >>> 6),
- con(n),
- ..._encode(ns),
- ];
- }
- throw new Error("utf8");
- }
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