ToBase64Transform.cs

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using System.Buffers;
using System.Buffers.Text;
 
namespace System.Security.Cryptography;
 
public class ToBase64Transform : ICryptoTransform, IDisposable
{
    public int InputBlockSize => 3;
 
    public int OutputBlockSize => 4;
 
    public bool CanTransformMultipleBlocks => true;
 
    public virtual bool CanReuseTransform => true;
 
    public int TransformBlock(byte[] inputBuffer, int inputOffset, int inputCount, byte[] outputBuffer, int outputOffset)
    {
        ThrowHelper.ValidateTransformBlock(inputBuffer, inputOffset, inputCount);
        int result;
        int num = Math.DivRem(inputCount, InputBlockSize, out result);
        if (num == 0)
        {
            ThrowHelper.ThrowArgumentOutOfRange(ThrowHelper.ExceptionArgument.inputCount);
        }
        if (outputBuffer == null)
        {
            ThrowHelper.ThrowArgumentNull(ThrowHelper.ExceptionArgument.outputBuffer);
        }
        if (result != 0)
        {
            ThrowHelper.ThrowArgumentOutOfRange(ThrowHelper.ExceptionArgument.inputCount);
        }
        int num2 = checked(num * OutputBlockSize);
        if (num2 > outputBuffer.Length - outputOffset)
        {
            ThrowHelper.ThrowArgumentOutOfRange(ThrowHelper.ExceptionArgument.outputBuffer);
        }
        Span<byte> span = inputBuffer.AsSpan(inputOffset, inputCount);
        Span<byte> utf = outputBuffer.AsSpan(outputOffset, num2);
        int bytesConsumed;
        int bytesWritten;
        OperationStatus operationStatus = Base64.EncodeToUtf8(span, utf, out bytesConsumed, out bytesWritten, isFinalBlock: false);
        return bytesWritten;
    }
 
    public byte[] TransformFinalBlock(byte[] inputBuffer, int inputOffset, int inputCount)
    {
        ThrowHelper.ValidateTransformBlock(inputBuffer, inputOffset, inputCount);
        if (inputCount == 0)
        {
            return Array.Empty<byte>();
        }
        Span<byte> span = inputBuffer.AsSpan(inputOffset, inputCount);
        int result;
        int num = Math.DivRem(inputCount, InputBlockSize, out result);
        int num2 = num + ((result != 0) ? 1 : 0);
        byte[] array = new byte[num2 * OutputBlockSize];
        int bytesConsumed;
        int bytesWritten;
        OperationStatus operationStatus = Base64.EncodeToUtf8(span, array, out bytesConsumed, out bytesWritten);
        return array;
    }
 
    public void Dispose()
    {
        Clear();
    }
 
    public void Clear()
    {
        Dispose(disposing: true);
        GC.SuppressFinalize(this);
    }
 
    protected virtual void Dispose(bool disposing)
    {
    }
 
    ~ToBase64Transform()
    {
        Dispose(disposing: false);
    }
}