src/Blockchain.Investments.Core/Infrastructure/Util.cs
using System;
namespace Blockchain.Investments.Core.Infrastructure
{
public static class Util
{
private static readonly long EpochMilliseconds = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc).Ticks / 10000L;
/// <summary>
/// Creates a sequential GUID according to SQL Server's ordering rules.
/// http://www.informit.com/articles/article.aspx?p=25862 (The Cost of GUIDs as Primary Keys)
/// </summary>
public static Guid NewSequentialId()
{
// This code was not reviewed to guarantee uniqueness under most conditions, nor completely optimize for avoiding
// page splits in SQL Server when doing inserts from multiple hosts, so do not re-use in production systems.
var guidBytes = Guid.NewGuid().ToByteArray();
// Get the milliseconds since Jan 1 1970.
byte[] sequential = BitConverter.GetBytes((DateTime.Now.Ticks / 10000L) - EpochMilliseconds);
// Discard the 2 most significant bytes, as we only care about the milliseconds increasing, but the highest ones should be 0 for several thousand years to come.
if (BitConverter.IsLittleEndian)
{
guidBytes[10] = sequential[5];
guidBytes[11] = sequential[4];
guidBytes[12] = sequential[3];
guidBytes[13] = sequential[2];
guidBytes[14] = sequential[1];
guidBytes[15] = sequential[0];
}
else
{
Buffer.BlockCopy(sequential, 2, guidBytes, 10, 6);
}
return new Guid(guidBytes);
}
}
}