C# と VB.NET の質問掲示板

たとえばこんな感じです。

namespace CrcLib {
  public class Crc {
    public static uint GetCrc32(byte[] buffer, ...) { ... }
    public static void InitCrcTable() { ... }
  }
}

Sub CalcCrc()
  CrcLib.Crc.InitCrcTable()
  Dim bytes As Byte()
  ...
  Dim result As UInteger = CrcLib.Crc.GetCrc32(bytes, ...)
End Sub

// C#のstaticメンバは型名からアクセスする必要があります。

No82337 で紹介した、

> Calculating CRC-32 in C# and .NET  
> https://damieng.com/blog/2006/08/08/calculating_crc32_in_c_and_net

で試してみましたが、511MB のファイルが 4 秒前後でした。ご参考まで

Option Strict On
Module Module1
    Sub Main()
        Dim crc32 As New ClassLibrary1.Crc32
        Dim hash As String = String.Empty
        Dim path As String = "C:\test.zip"

        Dim stopWatch As New Stopwatch
        stopWatch.Start()

        Using fs As System.IO.FileStream = System.IO.File.Open(path, System.IO.FileMode.Open)
            For Each b As Byte In crc32.ComputeHash(fs)
                hash += b.ToString("x2").ToLower()
            Next
        End Using

        stopWatch.Stop()
        Dim ts As TimeSpan = stopWatch.Elapsed
        Dim elapsedTime As String = String.Format("{0:00}:{1:00}:{2:00}.{3:00}",
                                    ts.Hours, ts.Minutes, ts.Seconds, ts.Milliseconds / 10)

        Console.WriteLine("CRC-32 is {0}", hash)
        Console.WriteLine(elapsedTime, "RunTime")
    End Sub
End Module