UniversalCryptoTransform.cs

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using System;
using System.Security.Cryptography;
 
namespace Internal.Cryptography;
 
internal abstract class UniversalCryptoTransform : ICryptoTransform, IDisposable
{
    public bool CanReuseTransform => true;
 
    public bool CanTransformMultipleBlocks => true;
 
    protected int PaddingSizeBytes => BasicSymmetricCipher.PaddingSizeInBytes;
 
    public int InputBlockSize => BasicSymmetricCipher.BlockSizeInBytes;
 
    public int OutputBlockSize => BasicSymmetricCipher.BlockSizeInBytes;
 
    protected PaddingMode PaddingMode { get; private set; }
 
    protected BasicSymmetricCipher BasicSymmetricCipher { get; private set; }
 
    public static UniversalCryptoTransform Create(PaddingMode paddingMode, BasicSymmetricCipher cipher, bool encrypting)
    {
        if (encrypting)
        {
            return new UniversalCryptoEncryptor(paddingMode, cipher);
        }
        return new UniversalCryptoDecryptor(paddingMode, cipher);
    }
 
    protected UniversalCryptoTransform(PaddingMode paddingMode, BasicSymmetricCipher basicSymmetricCipher)
    {
        PaddingMode = paddingMode;
        BasicSymmetricCipher = basicSymmetricCipher;
    }
 
    public void Dispose()
    {
        Dispose(disposing: true);
        GC.SuppressFinalize(this);
    }
 
    public int TransformBlock(byte[] inputBuffer, int inputOffset, int inputCount, byte[] outputBuffer, int outputOffset)
    {
        if (inputBuffer == null)
        {
            throw new ArgumentNullException("inputBuffer");
        }
        if (inputOffset < 0)
        {
            throw new ArgumentOutOfRangeException("inputOffset");
        }
        if (inputOffset > inputBuffer.Length)
        {
            throw new ArgumentOutOfRangeException("inputOffset");
        }
        if (inputCount <= 0)
        {
            throw new ArgumentOutOfRangeException("inputCount");
        }
        if (inputCount % InputBlockSize != 0)
        {
            throw new ArgumentOutOfRangeException("inputCount", System.SR.Cryptography_MustTransformWholeBlock);
        }
        if (inputCount > inputBuffer.Length - inputOffset)
        {
            throw new ArgumentOutOfRangeException("inputCount", System.SR.Cryptography_TransformBeyondEndOfBuffer);
        }
        if (outputBuffer == null)
        {
            throw new ArgumentNullException("outputBuffer");
        }
        if (outputOffset > outputBuffer.Length)
        {
            throw new ArgumentOutOfRangeException("outputOffset");
        }
        if (inputCount > outputBuffer.Length - outputOffset)
        {
            throw new ArgumentOutOfRangeException("outputOffset", System.SR.Cryptography_TransformBeyondEndOfBuffer);
        }
        return UncheckedTransformBlock(inputBuffer, inputOffset, inputCount, outputBuffer, outputOffset);
    }
 
    public byte[] TransformFinalBlock(byte[] inputBuffer, int inputOffset, int inputCount)
    {
        if (inputBuffer == null)
        {
            throw new ArgumentNullException("inputBuffer");
        }
        if (inputOffset < 0)
        {
            throw new ArgumentOutOfRangeException("inputOffset");
        }
        if (inputCount < 0)
        {
            throw new ArgumentOutOfRangeException("inputCount");
        }
        if (inputOffset > inputBuffer.Length)
        {
            throw new ArgumentOutOfRangeException("inputOffset");
        }
        if (inputCount > inputBuffer.Length - inputOffset)
        {
            throw new ArgumentOutOfRangeException("inputCount", System.SR.Cryptography_TransformBeyondEndOfBuffer);
        }
        return UncheckedTransformFinalBlock(inputBuffer, inputOffset, inputCount);
    }
 
    public abstract bool TransformOneShot(ReadOnlySpan<byte> input, Span<byte> output, out int bytesWritten);
 
    protected virtual void Dispose(bool disposing)
    {
        if (disposing)
        {
            BasicSymmetricCipher.Dispose();
        }
    }
 
    protected int UncheckedTransformBlock(byte[] inputBuffer, int inputOffset, int inputCount, byte[] outputBuffer, int outputOffset)
    {
        return UncheckedTransformBlock(inputBuffer.AsSpan(inputOffset, inputCount), outputBuffer.AsSpan(outputOffset));
    }
 
    protected abstract int UncheckedTransformBlock(ReadOnlySpan<byte> inputBuffer, Span<byte> outputBuffer);
 
    protected abstract byte[] UncheckedTransformFinalBlock(byte[] inputBuffer, int inputOffset, int inputCount);
 
    protected abstract int UncheckedTransformFinalBlock(ReadOnlySpan<byte> inputBuffer, Span<byte> outputBuffer);
}