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Is it a Hash Brown?It has been one crazy semester (I think the lack of activity can vouch for that). I've come up to the surface and see that a lot of the landscape has changed, take the emergence of CodeGear for example. I am hoping this is a breathe of new life that can revitalize the Delphi community and not just a last ditch effort (personally I think the BDS IDE is far better for development than VS). I am optimistic about the whole thing and hope they endure the 'rebirth process'.
As I was submerged in my own little world for a period of time, I had the need to calculate the Hash value for files. This actually turned out to server two purposes. The first being the verification of a file as original (intact) by comparing the hash value of the current and original file. Second, it turned out to be a fast way of identifying identical files. Often times a CRC is used to calculate a checksum, however I opted to make use of the System.Security.Cryptography Namespace. This Namespace has a number of useful hash functions including SHA1, SHA256 and SHA512. Surprisingly (or not) these are relatively easy to use and eliminate the need to formulate the algorithm on your own. Here it is in a couple of worlds:
Delphi:
uses
System.Security.Cryptography, System.IO;
procedure frmMain.ClearForm;
begin
txtSHA1.Text:= '';
txtSHA256.Text:= '';
txtSHA512.Text:= '';
end;
procedure frmMain.txtFileName_TextChanged(sender: System.Object; e: System.EventArgs);
begin
ToolTip1.SetToolTip(txtFileName,txtFileName.Text);
end;
procedure frmMain.btnCalculate_Click(sender: System.Object; e: System.EventArgs);
var
myCursor: System.Windows.Forms.Cursor;
oFileStream: FileStream;
lBytes: int64;
instance: FileInfo;
filecontents: Array of Byte;
result: Array of Byte;
SHA1M: SHA1Managed;
SHA256M: SHA256Managed;
SHA512M: SHA512Managed;
begin
myCursor:= Cursor;
Cursor:= Cursors.WaitCursor;
try
try
if not(txtFileName.Text='') then
begin
ErrorProvider1.SetError(btnFile,'');
instance:= FileInfo.Create(txtFileName.Text);
oFileStream:= instance.OpenRead;
lBytes:= oFileStream.Length;
SetLength(filecontents,lBytes);
oFileStream.Read(filecontents,0,lBytes);
oFileStream.Close;
SHA1M:= SHA1Managed.Create;
result:= SHA1M.ComputeHash(filecontents);
txtSHA1.Text:= Convert.ToBase64String(result);
SHA256M:= SHA256Managed.Create;
result:= SHA256M.ComputeHash(filecontents);
txtSHA256.Text:= Convert.ToBase64String(result);
SHA512M:= SHA512Managed.Create;
result:= SHA512M.ComputeHash(filecontents);
txtSHA512.Text:= Convert.ToBase64String(result);
end
else
begin
ErrorProvider1.SetError(btnFile,'Select a filename');
end;
except
on e: exception do
MessageBox.Show(e.Message, e.Source, MessageBoxButtons.OK,
MessageBoxIcon.Error);
end;
finally
Cursor:= myCursor;
end;
end;
procedure frmMain.btnFile_Click(sender: System.Object; e: System.EventArgs);
begin
if (ofdFileName.ShowDialog = System.Windows.Forms.DialogResult.OK) then
begin
ClearForm;
txtFileName.Text:= ofdFileName.FileName;
end;
end;
VB:
Imports System.Security.Cryptography
Imports System.IO
Public Class frmMain
Private Sub btnFile_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnFile.Click
If ofdFileName.ShowDialog Then
ClearForm()
txtFileName.Text = ofdFileName.FileName
End If
End Sub
Private Sub txtFileName_TextChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles txtFileName.TextChanged
ToolTip1.SetToolTip(txtFileName, txtFileName.Text)
End Sub
Private Sub ClearForm()
txtSHA1.Text = ""
txtSHA256.Text = ""
txtSHA512.Text = ""
End Sub
Private Sub btnCalculate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCalculate.Click
Dim myCursor As Cursor
Dim oFileStream As System.IO.FileStream
Dim lBytes As Long
Dim result() As Byte
myCursor = Cursor
Cursor = Cursors.WaitCursor
Try
If Not (txtFileName.Text = "") Then
ErrorProvider1.Clear() 'Introduced .NET 2.0
Dim instance As New FileInfo(txtFileName.Text)
oFileStream = instance.OpenRead()
lBytes = oFileStream.Length
Dim filecontents(lBytes) As Byte
oFileStream.Read(filecontents, 0, lBytes)
oFileStream.Close()
Dim sha1M As New SHA1Managed
result = sha1M.ComputeHash(filecontents)
txtSHA1.Text = Convert.ToBase64String(result)
Dim sha256M As New SHA256Managed
result = sha256M.ComputeHash(filecontents)
txtSHA256.Text = Convert.ToBase64String(result)
Dim sha512M As New SHA512Managed
result = sha512M.ComputeHash(filecontents)
txtSHA512.Text = Convert.ToBase64String(result)
Else
ErrorProvider1.SetError(btnFile, "Select a filename")
End If
Catch ex As Exception
MessageBox.Show(ex.Message, ex.Source, MessageBoxButtons.OK, MessageBoxIcon.Error)
Finally
Cursor = myCursor
End Try
End Sub
End Class
This is another post done with Live Writer, I think it is pretty 'groovy'.
Virtualization is cool TShellExecuteInfo That Special Folder Live Writer Test A RT_BITMAP told me so Tray it a bit easier Classic ASP and a Form Ye Old TFileEdit TypInfo is cool! A bit, byte and word
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