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// ==++==
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
// ==--==
// <OWNER>Microsoft</OWNER>
//
//
// Base64Transform.cs
//
// This file contains two ICryptoTransforms: ToBase64Transform and FromBase64Transform
// they may be attached to a CryptoStream in either read or write mode
namespace System.Security.Cryptography {
using System;
using System.IO;
using System.Text;
using System.Diagnostics.Contracts;
[Serializable]
[System.Runtime.InteropServices.ComVisible(true)]
public enum FromBase64TransformMode {
IgnoreWhiteSpaces = 0,
DoNotIgnoreWhiteSpaces = 1,
}
[System.Runtime.InteropServices.ComVisible(true)]
public class ToBase64Transform : ICryptoTransform {
// converting to Base64 takes 3 bytes input and generates 4 bytes output
public int InputBlockSize {
get { return(3); }
}
public int OutputBlockSize {
get { return(4); }
}
public bool CanTransformMultipleBlocks {
get { return(false); }
}
public virtual bool CanReuseTransform {
get { return(true); }
}
public int TransformBlock(byte[] inputBuffer, int inputOffset, int inputCount, byte[] outputBuffer, int outputOffset) {
// Do some validation
if (inputBuffer == null) throw new ArgumentNullException("inputBuffer");
if (inputOffset < 0) throw new ArgumentOutOfRangeException("inputOffset", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
if (inputCount < 0 || (inputCount > inputBuffer.Length)) throw new ArgumentException(Environment.GetResourceString("Argument_InvalidValue"));
if ((inputBuffer.Length - inputCount) < inputOffset) throw new ArgumentException(Environment.GetResourceString("Argument_InvalidOffLen"));
Contract.EndContractBlock();
// for now, only convert 3 bytes to 4
char[] temp = new char[4];
Convert.ToBase64CharArray(inputBuffer, inputOffset, 3, temp, 0);
byte[] tempBytes = Encoding.ASCII.GetBytes(temp);
if (tempBytes.Length != 4) throw new CryptographicException(Environment.GetResourceString( "Cryptography_SSE_InvalidDataSize" ));
Buffer.BlockCopy(tempBytes, 0, outputBuffer, outputOffset, tempBytes.Length);
return(tempBytes.Length);
}
public byte[] TransformFinalBlock(byte[] inputBuffer, int inputOffset, int inputCount) {
// Do some validation
if (inputBuffer == null) throw new ArgumentNullException("inputBuffer");
if (inputOffset < 0) throw new ArgumentOutOfRangeException("inputOffset", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
if (inputCount < 0 || (inputCount > inputBuffer.Length)) throw new ArgumentException(Environment.GetResourceString("Argument_InvalidValue"));
if ((inputBuffer.Length - inputCount) < inputOffset) throw new ArgumentException(Environment.GetResourceString("Argument_InvalidOffLen"));
Contract.EndContractBlock();
// Convert.ToBase64CharArray already does padding, so all we have to check is that
// the inputCount wasn't 0
// again, for now only a block at a time
if (inputCount == 0) {
return(EmptyArray<Byte>.Value);
} else {
char[] temp = new char[4];
Convert.ToBase64CharArray(inputBuffer, inputOffset, inputCount, temp, 0);
byte[] tempBytes = Encoding.ASCII.GetBytes(temp);
return(tempBytes);
}
}
// must implement IDisposable, but in this case there's nothing to do.
public void Dispose() {
Clear();
}
public void Clear() {
Dispose(true);
GC.SuppressFinalize(this);
}
protected virtual void Dispose(bool disposing) {
}
~ToBase64Transform() {
//
// A finalizer is not necessary here, however since we shipped a finalizer that called
// Dispose(false) in v2.0, we need to keep it around in case any existing code had subclassed
// this transform and expects to have a base class finalizer call its dispose method
//
Dispose(false);
}
}
[System.Runtime.InteropServices.ComVisible(true)]
public class FromBase64Transform : ICryptoTransform {
private byte[] _inputBuffer = new byte[4];
private int _inputIndex;
private FromBase64TransformMode _whitespaces;
// Constructors
public FromBase64Transform() : this(FromBase64TransformMode.IgnoreWhiteSpaces) {}
public FromBase64Transform(FromBase64TransformMode whitespaces) {
_whitespaces = whitespaces;
_inputIndex = 0;
}
// converting from Base64 generates 3 bytes output from each 4 bytes input block
public int InputBlockSize {
get { return(1); }
}
public int OutputBlockSize {
get { return(3); }
}
public bool CanTransformMultipleBlocks {
get { return(false); }
}
public virtual bool CanReuseTransform {
get { return(true); }
}
public int TransformBlock(byte[] inputBuffer, int inputOffset, int inputCount, byte[] outputBuffer, int outputOffset) {
// Do some validation
if (inputBuffer == null) throw new ArgumentNullException("inputBuffer");
if (inputOffset < 0) throw new ArgumentOutOfRangeException("inputOffset", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
if (inputCount < 0 || (inputCount > inputBuffer.Length)) throw new ArgumentException(Environment.GetResourceString("Argument_InvalidValue"));
if ((inputBuffer.Length - inputCount) < inputOffset) throw new ArgumentException(Environment.GetResourceString("Argument_InvalidOffLen"));
Contract.EndContractBlock();
if (_inputBuffer == null)
throw new ObjectDisposedException(null, Environment.GetResourceString("ObjectDisposed_Generic"));
byte[] temp = new byte[inputCount];
char[] tempChar;
int effectiveCount;
if (_whitespaces == FromBase64TransformMode.IgnoreWhiteSpaces) {
temp = DiscardWhiteSpaces(inputBuffer, inputOffset, inputCount);
effectiveCount = temp.Length;
} else {
Buffer.InternalBlockCopy(inputBuffer, inputOffset, temp, 0, inputCount);
effectiveCount = inputCount;
}
if (effectiveCount + _inputIndex < 4) {
Buffer.InternalBlockCopy(temp, 0, _inputBuffer, _inputIndex, effectiveCount);
_inputIndex += effectiveCount;
return 0;
}
// Get the number of 4 bytes blocks to transform
int numBlocks = (effectiveCount + _inputIndex) / 4;
byte[] transformBuffer = new byte[_inputIndex + effectiveCount];
Buffer.InternalBlockCopy(_inputBuffer, 0, transformBuffer, 0, _inputIndex);
Buffer.InternalBlockCopy(temp, 0, transformBuffer, _inputIndex, effectiveCount);
_inputIndex = (effectiveCount + _inputIndex) % 4;
Buffer.InternalBlockCopy(temp, effectiveCount - _inputIndex, _inputBuffer, 0, _inputIndex);
tempChar = Encoding.ASCII.GetChars(transformBuffer, 0, 4*numBlocks);
byte[] tempBytes = Convert.FromBase64CharArray(tempChar, 0, 4*numBlocks);
Buffer.BlockCopy(tempBytes, 0, outputBuffer, outputOffset, tempBytes.Length);
return(tempBytes.Length);
}
public byte[] TransformFinalBlock(byte[] inputBuffer, int inputOffset, int inputCount) {
// Do some validation
if (inputBuffer == null) throw new ArgumentNullException("inputBuffer");
if (inputOffset < 0) throw new ArgumentOutOfRangeException("inputOffset", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
if (inputCount < 0 || (inputCount > inputBuffer.Length)) throw new ArgumentException(Environment.GetResourceString("Argument_InvalidValue"));
if ((inputBuffer.Length - inputCount) < inputOffset) throw new ArgumentException(Environment.GetResourceString("Argument_InvalidOffLen"));
Contract.EndContractBlock();
if (_inputBuffer == null)
throw new ObjectDisposedException(null, Environment.GetResourceString("ObjectDisposed_Generic"));
byte[] temp = new byte[inputCount];
char[] tempChar;
int effectiveCount;
if (_whitespaces == FromBase64TransformMode.IgnoreWhiteSpaces) {
temp = DiscardWhiteSpaces(inputBuffer, inputOffset, inputCount);
effectiveCount = temp.Length;
} else {
Buffer.InternalBlockCopy(inputBuffer, inputOffset, temp, 0, inputCount);
effectiveCount = inputCount;
}
if (effectiveCount + _inputIndex < 4) {
Reset();
return (EmptyArray<Byte>.Value);
}
// Get the number of 4 bytes blocks to transform
int numBlocks = (effectiveCount + _inputIndex) / 4;
byte[] transformBuffer = new byte[_inputIndex + effectiveCount];
Buffer.InternalBlockCopy(_inputBuffer, 0, transformBuffer, 0, _inputIndex);
Buffer.InternalBlockCopy(temp, 0, transformBuffer, _inputIndex, effectiveCount);
_inputIndex = (effectiveCount + _inputIndex) % 4;
Buffer.InternalBlockCopy(temp, effectiveCount - _inputIndex, _inputBuffer, 0, _inputIndex);
tempChar = Encoding.ASCII.GetChars(transformBuffer, 0, 4*numBlocks);
byte[] tempBytes = Convert.FromBase64CharArray(tempChar, 0, 4*numBlocks);
// reinitialize the transform
Reset();
return(tempBytes);
}
private byte[] DiscardWhiteSpaces(byte[] inputBuffer, int inputOffset, int inputCount) {
int i, iCount = 0;
for (i=0; i<inputCount; i++)
if (Char.IsWhiteSpace((char)inputBuffer[inputOffset + i])) iCount++;
byte[] rgbOut = new byte[inputCount - iCount];
iCount = 0;
for (i=0; i<inputCount; i++)
if (!Char.IsWhiteSpace((char)inputBuffer[inputOffset + i])) {
rgbOut[iCount++] = inputBuffer[inputOffset + i];
}
return rgbOut;
}
// must implement IDisposable, which in this case means clearing the input buffer
public void Dispose() {
Dispose(true);
GC.SuppressFinalize(this);
}
// Reset the state of the transform so it can be used again
private void Reset() {
_inputIndex = 0;
}
public void Clear() {
Dispose();
}
protected virtual void Dispose(bool disposing) {
// we always want to clear the input buffer
if (disposing) {
if (_inputBuffer != null)
Array.Clear(_inputBuffer, 0, _inputBuffer.Length);
_inputBuffer = null;
_inputIndex = 0;
}
}
~FromBase64Transform() {
//
// A finalizer is not necessary here, however since we shipped a finalizer that called
// Dispose(false) in v2.0, we need to keep it around in case any existing code had subclassed
// this transform and expects to have a base class finalizer call its dispose method
//
Dispose(false);
}
}
}
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