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BSON id 生成器的 C# 实现?

转载 作者:太空宇宙 更新时间:2023-11-03 20:59:13 24 4
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有谁知道是否存在 BSON ID 生成器的现有 c# 实现?

我需要在 .NET 客户端上生成 Mongodb objectID,但无法使用外部 dll,因此需要在代码中完成。我在谷歌上找不到任何东西,所以可能最终不得不自己写,但我想先和其他人核实一下。

谢谢。

最佳答案

您可以简单地复制 implementation如果您不允许引用该包,请添加到您的代码库。下面是它的简化版本。

using System;
using System.Diagnostics;
using System.Runtime.CompilerServices;
using System.Security;
using System.Threading;

public struct ObjectId
{
private static readonly ObjectId __emptyInstance = default(ObjectId);
private static readonly int __staticMachine = (GetMachineHash() + GetAppDomainId()) & 0x00ffffff;
private static readonly short __staticPid = GetPid();
private static int __staticIncrement = new Random().Next();
private static readonly DateTime __unixEpoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);

private readonly int _a;
private readonly int _b;
private readonly int _c;

private ObjectId(int timestamp, int machine, short pid, int increment)
{
_a = timestamp;
_b = (machine << 8) | ((pid >> 8) & 0xff);
_c = (pid << 24) | increment;
}

public static ObjectId GenerateNewId()
{
return GenerateNewId(GetTimestampFromDateTime(DateTime.UtcNow));
}

public static ObjectId GenerateNewId(int timestamp)
{
var increment = Interlocked.Increment(ref __staticIncrement) & 0x00ffffff; // only use low order 3 bytes
return new ObjectId(timestamp, __staticMachine, __staticPid, increment);
}

private static int GetAppDomainId()
{
return AppDomain.CurrentDomain.Id;
}

[MethodImpl(MethodImplOptions.NoInlining)]
private static int GetCurrentProcessId()
{
return Process.GetCurrentProcess().Id;
}

private static int GetMachineHash()
{
var machineName = GetMachineName();
return 0x00ffffff & machineName.GetHashCode(); // use first 3 bytes of hash
}

private static string GetMachineName()
{
return Environment.MachineName;
}

private static short GetPid()
{
try
{
return (short) GetCurrentProcessId(); // use low order two bytes only
}
catch (SecurityException)
{
return 0;
}
}

private static int GetTimestampFromDateTime(DateTime timestamp)
{
var secondsSinceEpoch = (long) Math.Floor((ToUniversalTime(timestamp) - __unixEpoch).TotalSeconds);
if (secondsSinceEpoch < int.MinValue || secondsSinceEpoch > int.MaxValue)
throw new ArgumentOutOfRangeException("timestamp");
return (int) secondsSinceEpoch;
}

public override string ToString()
{
var c = new char[24];
c[0] = ToHexChar((_a >> 28) & 0x0f);
c[1] = ToHexChar((_a >> 24) & 0x0f);
c[2] = ToHexChar((_a >> 20) & 0x0f);
c[3] = ToHexChar((_a >> 16) & 0x0f);
c[4] = ToHexChar((_a >> 12) & 0x0f);
c[5] = ToHexChar((_a >> 8) & 0x0f);
c[6] = ToHexChar((_a >> 4) & 0x0f);
c[7] = ToHexChar(_a & 0x0f);
c[8] = ToHexChar((_b >> 28) & 0x0f);
c[9] = ToHexChar((_b >> 24) & 0x0f);
c[10] = ToHexChar((_b >> 20) & 0x0f);
c[11] = ToHexChar((_b >> 16) & 0x0f);
c[12] = ToHexChar((_b >> 12) & 0x0f);
c[13] = ToHexChar((_b >> 8) & 0x0f);
c[14] = ToHexChar((_b >> 4) & 0x0f);
c[15] = ToHexChar(_b & 0x0f);
c[16] = ToHexChar((_c >> 28) & 0x0f);
c[17] = ToHexChar((_c >> 24) & 0x0f);
c[18] = ToHexChar((_c >> 20) & 0x0f);
c[19] = ToHexChar((_c >> 16) & 0x0f);
c[20] = ToHexChar((_c >> 12) & 0x0f);
c[21] = ToHexChar((_c >> 8) & 0x0f);
c[22] = ToHexChar((_c >> 4) & 0x0f);
c[23] = ToHexChar(_c & 0x0f);
return new string(c);
}

private static char ToHexChar(int value)
{
return (char) (value + (value < 10 ? '0' : 'a' - 10));
}

private static DateTime ToUniversalTime(DateTime dateTime)
{
if (dateTime == DateTime.MinValue)
return DateTime.SpecifyKind(DateTime.MinValue, DateTimeKind.Utc);
if (dateTime == DateTime.MaxValue)
return DateTime.SpecifyKind(DateTime.MaxValue, DateTimeKind.Utc);
return dateTime.ToUniversalTime();
}
}

关于BSON id 生成器的 C# 实现?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/47349803/

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