generate method
- {V7Options? options}
v7() Generates a time-based version 7 UUID
By default it will generate a string based off current time in Unix Epoch, and will return a string.
The first argument is an options map that takes various configuration options detailed in the readme.
https://datatracker.ietf.org/doc/html/draft-peabody-dispatch-new-uuid-format#section-4.3
Implementation
String generate({V7Options? options}) {
var buf = Uint8List(16);
int time = options?.time ?? (DateTime.now().toUtc()).millisecondsSinceEpoch;
var timeList32 = Uint8List(8)..buffer.asUint32List()[0] = time >> 16;
var timeList16 = Uint8List(8)..buffer.asUint16List()[0] = time;
var endIndex32 = timeList32.length - 1;
var endIndex16 = timeList16.length - 1;
while (endIndex32 >= 0 && timeList32[endIndex32] == 0) {
endIndex32--;
}
while (endIndex16 >= 0 && timeList16[endIndex16] == 0) {
endIndex16--;
}
timeList32 = timeList32.sublist(0, endIndex32 + 1);
timeList16 = timeList16.sublist(0, endIndex16 + 1);
buf.setAll(0, timeList32.reversed);
buf.setAll(4, timeList16.reversed);
List<int> randomBytes = options?.randomBytes ?? _randomData();
buf.setRange(6, 16, randomBytes);
buf.setRange(6, 7, [buf.getRange(6, 7).last & 0x0f | 0x70]);
buf.setRange(8, 9, [buf.getRange(8, 9).last & 0x3f | 0x80]);
return UuidParsing.unparse(buf);
}