FromBase64Transform.TransformFinalBlock(Byte[], Int32, Int32) Methode
Definitie
Belangrijk
Bepaalde informatie heeft betrekking op een voorlopige productversie die aanzienlijk kan worden gewijzigd voordat deze wordt uitgebracht. Microsoft biedt geen enkele expliciete of impliciete garanties met betrekking tot de informatie die hier wordt verstrekt.
Converteert de opgegeven regio van de opgegeven bytematrix van basis 64.
public:
virtual cli::array <System::Byte> ^ TransformFinalBlock(cli::array <System::Byte> ^ inputBuffer, int inputOffset, int inputCount);public byte[] TransformFinalBlock(byte[] inputBuffer, int inputOffset, int inputCount);abstract member TransformFinalBlock : byte[] * int * int -> byte[]
override this.TransformFinalBlock : byte[] * int * int -> byte[]Public Function TransformFinalBlock (inputBuffer As Byte(), inputOffset As Integer, inputCount As Integer) As Byte()Parameters
- inputBuffer
- Byte[]
De invoer die moet worden geconverteerd van basis 64.
- inputOffset
- Int32
De verschuiving in de bytematrix waaruit gegevens moeten worden gebruikt.
- inputCount
- Int32
Het aantal bytes in de bytematrix dat moet worden gebruikt als gegevens.
Retouren
Byte[]
De berekende conversie.
Implementeringen
Uitzonderingen
Het huidige FromBase64Transform object is al verwijderd.
inputBuffer heeft een ongeldige offsetlengte.
– of –
inputCount heeft een ongeldige waarde.
inputOffset valt buiten het bereik. Voor deze parameter is een niet-negatief getal vereist.
inputBuffer is null.
Voorbeelden
In het volgende voorbeeld wordt een met base 64 gecodeerd bestand ontsleuteld naar een uitvoertekstbestand.
using System;
using System.IO;
using System.Security.Cryptography;
class Members
{
[STAThread]
static void Main(string[] args)
{
string appPath = (System.IO.Directory.GetCurrentDirectory() );
appPath = appPath + "..\\\\..\\\\..\\";
// Insert your file names into this method call.
EncodeFromFile(appPath + "program.cs", appPath + "code.enc");
DecodeFromFile(appPath + "code.enc", appPath + "roundtrip.txt");
}
// Read in the specified source file and write out an encoded target file.
private static void EncodeFromFile(string sourceFile, string targetFile)
{
// Verify members.cs exists at the specified directory.
if (!File.Exists(sourceFile))
{
Console.Write("Unable to locate source file located at ");
Console.WriteLine(sourceFile + ".");
Console.Write("Please correct the path and run the ");
Console.WriteLine("sample again.");
return;
}
// Retrieve the input and output file streams.
using (FileStream inputFileStream =
new FileStream(sourceFile, FileMode.Open, FileAccess.Read))
{
using (FileStream outputFileStream =
new FileStream(targetFile, FileMode.Create, FileAccess.Write))
{
// Create a new ToBase64Transform object to convert to base 64.
ToBase64Transform base64Transform = new ToBase64Transform();
// Create a new byte array with the size of the output block size.
byte[] outputBytes = new byte[base64Transform.OutputBlockSize];
// Retrieve the file contents into a byte array.
byte[] inputBytes = new byte[inputFileStream.Length];
inputFileStream.Read(inputBytes, 0, inputBytes.Length);
// Verify that multiple blocks can not be transformed.
if (!base64Transform.CanTransformMultipleBlocks)
{
// Initialize the offset size.
int inputOffset = 0;
// Iterate through inputBytes transforming by blockSize.
int inputBlockSize = base64Transform.InputBlockSize;
while (inputBytes.Length - inputOffset > inputBlockSize)
{
base64Transform.TransformBlock(
inputBytes,
inputOffset,
inputBytes.Length - inputOffset,
outputBytes,
0);
inputOffset += base64Transform.InputBlockSize;
outputFileStream.Write(
outputBytes,
0,
base64Transform.OutputBlockSize);
}
// Transform the final block of data.
outputBytes = base64Transform.TransformFinalBlock(
inputBytes,
inputOffset,
inputBytes.Length - inputOffset);
outputFileStream.Write(outputBytes, 0, outputBytes.Length);
Console.WriteLine("Created encoded file at " + targetFile);
}
// Determine if the current transform can be reused.
if (!base64Transform.CanReuseTransform)
{
// Free any used resources.
base64Transform.Clear();
}
}
}
}
public static void DecodeFromFile(string inFileName, string outFileName)
{
using (FromBase64Transform myTransform = new FromBase64Transform(FromBase64TransformMode.IgnoreWhiteSpaces))
{
byte[] myOutputBytes = new byte[myTransform.OutputBlockSize];
// Open the input and output files.
using (FileStream myInputFile = new FileStream(inFileName, FileMode.Open, FileAccess.Read))
{
using (FileStream myOutputFile = new FileStream(outFileName, FileMode.Create, FileAccess.Write))
{
// Retrieve the file contents into a byte array.
byte[] myInputBytes = new byte[myInputFile.Length];
myInputFile.Read(myInputBytes, 0, myInputBytes.Length);
// Transform the data in chunks the size of InputBlockSize.
int i = 0;
while (myInputBytes.Length - i > 4/*myTransform.InputBlockSize*/)
{
int bytesWritten = myTransform.TransformBlock(myInputBytes, i, 4/*myTransform.InputBlockSize*/, myOutputBytes, 0);
i += 4/*myTransform.InputBlockSize*/;
myOutputFile.Write(myOutputBytes, 0, bytesWritten);
}
// Transform the final block of data.
myOutputBytes = myTransform.TransformFinalBlock(myInputBytes, i, myInputBytes.Length - i);
myOutputFile.Write(myOutputBytes, 0, myOutputBytes.Length);
// Free up any used resources.
myTransform.Clear();
}
}
}
}
}
Imports System.IO
Imports System.Security.Cryptography
Friend Class Members
<STAThread()> _
Shared Sub Main(ByVal args() As String)
Dim appPath As String = (System.IO.Directory.GetCurrentDirectory())
appPath = appPath & "..\\..\\..\"
' Insert your file names into this method call.
EncodeFromFile(appPath & "program.vb", appPath & "code.enc")
DecodeFromFile(appPath & "code.enc", appPath & "roundtrip.txt")
End Sub
' Read in the specified source file and write out an encoded target file.
Private Shared Sub EncodeFromFile(ByVal sourceFile As String, ByVal targetFile As String)
' Verify members.cs exists at the specified directory.
If Not File.Exists(sourceFile) Then
Console.Write("Unable to locate source file located at ")
Console.WriteLine(sourceFile & ".")
Console.Write("Please correct the path and run the ")
Console.WriteLine("sample again.")
Return
End If
' Retrieve the input and output file streams.
Using inputFileStream As New FileStream(sourceFile, FileMode.Open, FileAccess.Read)
Using outputFileStream As New FileStream(targetFile, FileMode.Create, FileAccess.Write)
' Create a new ToBase64Transform object to convert to base 64.
Dim base64Transform As New ToBase64Transform()
' Create a new byte array with the size of the output block size.
Dim outputBytes(base64Transform.OutputBlockSize - 1) As Byte
' Retrieve the file contents into a byte array.
Dim inputBytes(inputFileStream.Length - 1) As Byte
inputFileStream.Read(inputBytes, 0, inputBytes.Length)
' Verify that multiple blocks can not be transformed.
If Not base64Transform.CanTransformMultipleBlocks Then
' Initializie the offset size.
Dim inputOffset As Integer = 0
' Iterate through inputBytes transforming by blockSize.
Dim inputBlockSize As Integer = base64Transform.InputBlockSize
Do While inputBytes.Length - inputOffset > inputBlockSize
base64Transform.TransformBlock(inputBytes, inputOffset, inputBytes.Length - inputOffset, outputBytes, 0)
inputOffset += base64Transform.InputBlockSize
outputFileStream.Write(outputBytes, 0, base64Transform.OutputBlockSize)
Loop
' Transform the final block of data.
outputBytes = base64Transform.TransformFinalBlock(inputBytes, inputOffset, inputBytes.Length - inputOffset)
outputFileStream.Write(outputBytes, 0, outputBytes.Length)
Console.WriteLine("Created encoded file at " & targetFile)
End If
' Determine if the current transform can be reused.
If Not base64Transform.CanReuseTransform Then
' Free up any used resources.
base64Transform.Clear()
End If
End Using
End Using
End Sub
Public Shared Sub DecodeFromFile(ByVal inFileName As String, ByVal outFileName As String)
Using myTransform As New FromBase64Transform(FromBase64TransformMode.IgnoreWhiteSpaces)
Dim myOutputBytes(myTransform.OutputBlockSize - 1) As Byte
'Open the input and output files.
Using myInputFile As New FileStream(inFileName, FileMode.Open, FileAccess.Read)
Using myOutputFile As New FileStream(outFileName, FileMode.Create, FileAccess.Write)
'Retrieve the file contents into a byte array.
Dim myInputBytes(myInputFile.Length - 1) As Byte
myInputFile.Read(myInputBytes, 0, myInputBytes.Length)
'Transform the data in chunks the size of InputBlockSize.
Dim i As Integer = 0
Do While myInputBytes.Length - i > 4 'myTransform.InputBlockSize
Dim bytesWritten As Int32 = myTransform.TransformBlock(myInputBytes, i, 4, myOutputBytes, 0) 'myTransform.InputBlockSize
i += 4 'myTransform.InputBlockSize
myOutputFile.Write(myOutputBytes, 0, bytesWritten)
Loop
'Transform the final block of data.
myOutputBytes = myTransform.TransformFinalBlock(myInputBytes, i, myInputBytes.Length - i)
myOutputFile.Write(myOutputBytes, 0, myOutputBytes.Length)
'Free up any used resources.
myTransform.Clear()
End Using
End Using
End Using
End Sub
End Class