27 lines
889 B
Dart
27 lines
889 B
Dart
import 'dart:math';
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class Uuid {
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final Random _random = Random();
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/// Generate a version 4 (random) uuid. This is a uuid scheme that only uses
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/// random numbers as the source of the generated uuid.
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String generateV4() {
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// Generate xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx / 8-4-4-4-12.
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final special = 8 + _random.nextInt(4);
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return '${_bitsDigits(16, 4)}${_bitsDigits(16, 4)}-'
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'${_bitsDigits(16, 4)}-'
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'4${_bitsDigits(12, 3)}-'
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'${_printDigits(special, 1)}${_bitsDigits(12, 3)}-'
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'${_bitsDigits(16, 4)}${_bitsDigits(16, 4)}${_bitsDigits(16, 4)}';
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}
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String _bitsDigits(int bitCount, int digitCount) =>
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_printDigits(_generateBits(bitCount), digitCount);
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int _generateBits(int bitCount) => _random.nextInt(1 << bitCount);
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String _printDigits(int value, int count) =>
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value.toRadixString(16).padLeft(count, '0');
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}
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