private static async Task TransformAsync(this byte[] input, ICryptoTransform transform,
Stream streamToWrite, CancellationToken token, bool disposeOutput,
int byteOffset, int byteCount)
{
using (var outputWrapper = new WrappedStream(streamToWrite, disposeOutput))
{
using (var transformer = new CryptoStream(outputWrapper, transform, CryptoStreamMode.Write))
{
await transformer.WriteAsync(input, byteOffset, byteCount, token).ConfigureAwait(false);
await transformer.FlushAsync(token).ConfigureAwait(false);
await outputWrapper.FlushAsync(token).ConfigureAwait(false);
await streamToWrite.FlushAsync(token).ConfigureAwait(false);
}
}
}
/// <summary>
/// Reads from <paramref name="streamToRead"/> and writes transformed data on <paramref name="streamToWrite"/>,
/// using <paramref name="transform"/>, while observing <paramref name="token"/>.
/// </summary>
/// <param name="streamToRead">Stream to read from</param>
/// <param name="transform">transform to use</param>
/// <param name="streamToWrite">Stream to write transformed data to.</param>
/// <param name="token">Cancellation token</param>
/// <param name="disposeInput">If true, disposes <paramref name="streamToRead"/> upon operation completion, else leaves it open</param>
/// <param name="disposeOutput">If true, disposes <paramref name="streamToWrite"/> upon operation completion, else leaves it open</param>
/// <param name="bufferSize">Buffer size</param>
public static async Task TransformAsync(this Stream streamToRead, ICryptoTransform transform,
Stream streamToWrite, CancellationToken token, bool disposeInput = false,
bool disposeOutput = false, int bufferSize = StdLookUps.DefaultBufferSize)
{
using (var outputWrapper = new WrappedStream(streamToWrite, disposeOutput))
{
using (var transformer = new CryptoStream(outputWrapper, transform, CryptoStreamMode.Write))
{
using (var inputWrapper = new WrappedStream(streamToRead, disposeInput))
{
await inputWrapper.CopyToAsync(transformer, bufferSize, token).ConfigureAwait(false);
await transformer.FlushAsync(token).ConfigureAwait(false);
await outputWrapper.FlushAsync(token).ConfigureAwait(false);
await streamToWrite.FlushAsync(token).ConfigureAwait(false);
}
}
}
}
/// <summary>
/// Reads from <paramref name="streamToRead"/> and prepares decoded byte array, (return as segment,
/// idea is to save on array copy to remain low on latency n memory as perhaps segment can serve the purpose),
/// using <paramref name="transform"/>, while observing <paramref name="token"/>.
/// </summary>
/// <param name="streamToRead">Stream to read from</param>
/// <param name="transform">transform to use</param>
/// <param name="token">Cancellation token</param>
/// <param name="disposeInput">If true, disposes <paramref name="streamToRead"/> upon operation completion, else leaves it open</param>
/// <param name="bufferSize">Buffer size</param>
public static async Task <ArraySegment <byte> > TransformAsSegmentAsync(this Stream streamToRead,
ICryptoTransform transform, CancellationToken token, bool disposeInput = false,
int bufferSize = StdLookUps.DefaultBufferSize)
{
using (var inputWrapper = new WrappedStream(streamToRead, disposeInput))
{
using (var transformer = new CryptoStream(inputWrapper, transform,
CryptoStreamMode.Read))
{
using (var localBuffer = new MemoryStream())
{
await transformer.CopyToAsync(localBuffer, bufferSize, token).ConfigureAwait(false);
return(localBuffer.TryGetBuffer(out ArraySegment <byte> buffer)
.ThrowIfNot(DdnDfErrorCode.NullObject,
"Something horribly went wrong with" +
$" {nameof(MemoryStream)} implementation", buffer));
}
}
}
}
private static async Task TransformChunksAsync(Stream writable, ICryptoTransform transform,
int length, Encoding enc, CancellationToken token, bool disposeOutput, int chunkSize,
Action <int, char[], int, int> copyToAction)
{
using (var outputWrapper = new WrappedStream(writable, disposeOutput))
{
using (var transformer = new CryptoStream(outputWrapper, transform,
CryptoStreamMode.Write))
{
var bytes = enc.GetPreamble();
if (bytes.Length > 0)
{
await transformer.WriteAsync(bytes, 0, bytes.Length, token)
.ConfigureAwait(false);
}
var charArr = new char[chunkSize];
bytes = new byte[enc.GetMaxByteCount(chunkSize)];
var charCnt = length;
var position = 0;
while (charCnt > 0)
{
if (charCnt > chunkSize)
{
charCnt = chunkSize;
}
copyToAction(position, charArr, 0, charCnt);
var byteCnt = enc.GetBytes(charArr, 0, charCnt, bytes, 0);
await transformer.WriteAsync(bytes, 0, byteCnt, token).ConfigureAwait(false);
position += charCnt;
charCnt = length - position;
}
await transformer.FlushAsync(token).ConfigureAwait(false);
await outputWrapper.FlushAsync(token).ConfigureAwait(false);
await writable.FlushAsync(token).ConfigureAwait(false);
}
}
}
/// <summary>
/// Reads from <paramref name="streamToRead"/> and appends transformed string to <paramref name="appendTo"/>,
/// using <paramref name="transform"/> and <paramref name="encoding"/>, while observing <paramref name="token"/>.
/// </summary>
/// <param name="streamToRead">Stream to read from</param>
/// <param name="transform">transform to use</param>
/// <param name="appendTo">StringBuilder to write transformed data to.</param>
/// <param name="token">Cancellation token</param>
/// <param name="disposeInput">If true, disposes <paramref name="streamToRead"/> upon operation completion, else leaves it open</param>
/// <param name="encoding">Encoding to use to compose string characters, if not supplied UTF8 is used</param>
/// <param name="bufferSize">Buffer size</param>
public static async Task TransformAsync(this Stream streamToRead, ICryptoTransform transform,
StringBuilder appendTo, CancellationToken token, bool disposeInput = false,
Encoding encoding = null, int bufferSize = StdLookUps.DefaultBufferSize)
{
using (var inputWrapper = new WrappedStream(streamToRead, disposeInput))
{
using (var transformer = new CryptoStream(inputWrapper, transform,
CryptoStreamMode.Read))
{
using (var streamReader = new StreamReader(transformer, encoding ?? Encoding.UTF8,
true, bufferSize, true))
{
var charBuffer = new char[bufferSize];
int charCnt;
while ((charCnt = await streamReader.ReadAsync(charBuffer, 0, bufferSize)
.ConfigureAwait(false)) != 0)
{
appendTo.Append(charBuffer, 0, charCnt);
token.ThrowIfCancellationRequested();
}
}
}
}
}
