/// <summary>
/// Generates a unique, sequential, Base36 string, 16 characters long.
/// The first 10 characters are the microseconds elapsed since the InService DateTime
/// (constant field you hardcode in this file).
/// The next 2 characters are a compressed checksum of the MD5 of this host.
/// The next 1 character is a reserved constant of 36 ('Z' in Base36).
/// The last 3 characters are random number less than 46655 additional for additional uniqueness.
/// </summary>
/// <param name="delimiter">If provided, formats the ID as four groups of
/// 4 characters separated by the delimiter.</param>
/// <returns>Returns a unique, sequential, 16-character Base36 string</returns>
public static string NewBase36String(string delimiter)
{
// For 10 chars from timestamp, microseconds since InService, uses Stopwatch...
long microseconds = initStaticsReturnMicroseconds();
// For 2 chars from host id MD5...
string hostHash = (_hostHash ?? (_hostHash = ComputeHostHash()));
// 1 reserved char; static largest base36 digit.
// If the same ID system, scheme and sequence is still in use
// more than 115.85 years after in-service date, decrements
// 'reserved' by 1 for each whole multiple of 115 years
// elapsed, up to 35 times max. If the same system, scheme
// and sequence is still in service 3,850 years from the
// initial go-live, you probably have bigger problems than
// ID collisions...
int reserved = _reserved;
// 3 chars random in Base36 = 46656 units
string rndHexStr = getRandomDigits();
StringBuilder sb = new StringBuilder();
sb.Append(Base36Converter.FromInt64(microseconds).PadLeft(10, '0'));
sb.Length = 10;
sb.Append(hostHash.PadLeft(2, '0'));
sb.Length = 12;
sb.Append(Base36Converter.FromInt32(reserved));
sb.Length = 13;
sb.Append(Base36Converter.FromHex(rndHexStr).PadLeft(3, '0'));
sb.Length = 16;
if (!string.IsNullOrEmpty(delimiter))
{
sb.Insert(12, delimiter);
sb.Insert(8, delimiter);
sb.Insert(4, delimiter);
}
return(sb.ToString());
}
