// uuid 解码参数
const separator = '@';
const HexChars = '0123456789abcdef'.split('');
const _t = ['', '', '', ''];
const UuidTemplate = _t.concat(_t, '-', _t, '-', _t, '-', _t, '-', _t, _t, _t);
const Indices = UuidTemplate.map((x, i) => (x === '-' ? NaN : i)).filter(Number.isFinite);
const BASE64_KEYS = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';
const values = new Array(123); // max char code in base64Keys
for (let i = 0; i < 123; ++i) { values[i] = 64; } // fill with placeholder('=') index
for (let i = 0; i < 64; ++i) { values[BASE64_KEYS.charCodeAt(i)] = i; }
const BASE64_VALUES = values;
// 将3.8的uuid解码
function decodeUuid (base64) {
const strs = base64.split(separator);
const uuid = strs[0];
if (uuid.length !== 22) {
return base64;
}
UuidTemplate[0] = base64[0];
UuidTemplate[1] = base64[1];
for (let i = 2, j = 2; i < 22; i += 2) {
const lhs = BASE64_VALUES[base64.charCodeAt(i)];
const rhs = BASE64_VALUES[base64.charCodeAt(i + 1)];
UuidTemplate[Indices[j++]] = HexChars[lhs >> 2];
UuidTemplate[Indices[j++]] = HexChars[((lhs & 3) << 2) | rhs >> 4];
UuidTemplate[Indices[j++]] = HexChars[rhs & 0xF];
}
return base64.replace(uuid, UuidTemplate.join(''));
}