FromBase64Transform.TransformBlock Metoda
Definice
Důležité
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Převede zadanou oblast vstupního pole bajtů ze základny 64 a zkopíruje výsledek do zadané oblasti pole výstupních bajtů.
public:
virtual int TransformBlock(cli::array <System::Byte> ^ inputBuffer, int inputOffset, int inputCount, cli::array <System::Byte> ^ outputBuffer, int outputOffset);public int TransformBlock (byte[] inputBuffer, int inputOffset, int inputCount, byte[] outputBuffer, int outputOffset);abstract member TransformBlock : byte[] * int * int * byte[] * int -> int
override this.TransformBlock : byte[] * int * int * byte[] * int -> intPublic Function TransformBlock (inputBuffer As Byte(), inputOffset As Integer, inputCount As Integer, outputBuffer As Byte(), outputOffset As Integer) As IntegerParametry
- inputBuffer
- Byte[]
Vstup pro výpočty ze základny 64.
- inputOffset
- Int32
Posun do pole vstupních bajtů, ze kterého se mají začít používat data.
- inputCount
- Int32
Počet bajtů ve vstupním bajtovém poli, které se mají použít jako data.
- outputBuffer
- Byte[]
Výstup, do kterého chcete zapsat výsledek.
- outputOffset
- Int32
Posun do pole výstupních bajtů, ze kterého se mají začít zapisovat data.
Návraty
Počet zapsaných bajtů.
Implementuje
Výjimky
Aktuální FromBase64Transform objekt již byl odstraněn.
inputCount používá neplatnou hodnotu.
-nebo-
inputBuffer má neplatnou délku posunu.
inputOffset je mimo rozsah. Tento parametr vyžaduje nezáporné číslo.
inputBuffer je null.
Příklady
Následující příklad dešifruje základní soubor s kódováním 64 do výstupního textového souboru.
using namespace System;
using namespace System::IO;
using namespace System::Security::Cryptography;
class MyMainClass
{
public:
static void DecodeFromFile( String^ inFileName, String^ outFileName )
{
FromBase64Transform^ myTransform = gcnew FromBase64Transform( FromBase64TransformMode::IgnoreWhiteSpaces );
array<Byte>^myOutputBytes = gcnew array<Byte>(myTransform->OutputBlockSize);
//Open the input and output files.
FileStream^ myInputFile = gcnew FileStream( inFileName,FileMode::Open,FileAccess::Read );
FileStream^ myOutputFile = gcnew FileStream( outFileName,FileMode::Create,FileAccess::Write );
//Retrieve the file contents into a Byte array.
array<Byte>^myInputBytes = gcnew array<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->TransformBlock( myInputBytes, i, 4, myOutputBytes, 0 );
/*myTransform->InputBlockSize*/
i += 4;
/*myTransform->InputBlockSize*/
myOutputFile->Write( myOutputBytes, 0, myTransform->OutputBlockSize );
}
//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();
myInputFile->Close();
myOutputFile->Close();
}
};
int main()
{
MyMainClass * m = new MyMainClass;
//Insert your file names into this method call.
m->DecodeFromFile( "c:\\encoded.txt", "c:\\roundtrip.txt" );
}
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
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