/// <summary>
/// Writes the string into the stream.
/// </summary>
/// <remarks>
/// This method doesn't encode the length of the string.
/// </remarks>
/// <param name="stream">The stream to write into.</param>
/// <param name="value">The string to be encoded.</param>
/// <param name="context">The encoding.</param>
/// <param name="buffer">The buffer allocated by the caller needed for characters encoding.</param>
/// <exception cref="ArgumentException"><paramref name="buffer"/> is too small for encoding.</exception>
public static void WriteString(this Stream stream, string value, EncodingContext context, byte[] buffer)
{
if (value.Length == 0)
{
return;
}
//TODO: Should be rewritten for .NET Standard 2.1
if (context.Encoding.GetByteCount(value) <= buffer.Length)
{
stream.Write(buffer, 0, context.Encoding.GetBytes(value, 0, value.Length, buffer, 0));
}
else
{
var maxChars = buffer.Length / context.Encoding.GetMaxByteCount(1);
if (maxChars == 0)
{
throw new ArgumentException(ExceptionMessages.BufferTooSmall, nameof(buffer));
}
var encoder = context.GetEncoder();
for (int charStart = 0, numLeft = value.Length, charsRead; numLeft > 0; charStart += charsRead, numLeft -= charsRead)
{
charsRead = Math.Min(numLeft, maxChars);
stream.Write(buffer, 0, encoder.GetBytes(value, charStart, charsRead, buffer, charsRead == numLeft));
}
}
}
/// <summary>
/// Writes the string into the stream asynchronously.
/// </summary>
/// <remarks>
/// This method doesn't encode the length of the string.
/// </remarks>
/// <param name="stream">The stream to write into.</param>
/// <param name="value">The string to be encoded.</param>
/// <param name="context">The encoding context.</param>
/// <param name="buffer">The buffer allocated by the caller needed for characters encoding.</param>
/// <param name="token">The token that can be used to cancel the operation.</param>
/// <returns>The task representing asynchronous state of the operation.</returns>
/// <exception cref="ArgumentException"><paramref name="buffer"/> is too small for encoding.</exception>
public static async Task WriteStringAsync(this Stream stream, string value, EncodingContext context, byte[] buffer, CancellationToken token = default)
{
if (value.Length == 0)
{
return;
}
//TODO: Should be rewritten for .NET Standard 2.1
if (context.Encoding.GetByteCount(value) <= buffer.Length)
{
await stream.WriteAsync(buffer, 0, context.Encoding.GetBytes(value, 0, value.Length, buffer, 0), token).ConfigureAwait(false);
}
else
{
var maxChars = buffer.Length / context.Encoding.GetMaxByteCount(1);
if (maxChars == 0)
{
throw new ArgumentException(ExceptionMessages.BufferTooSmall, nameof(buffer));
}
var encoder = context.GetEncoder();
for (int charStart = 0, numLeft = value.Length, charsRead; numLeft > 0; charStart += charsRead, numLeft -= charsRead)
{
charsRead = Math.Min(numLeft, maxChars);
await stream.WriteAsync(buffer, 0, encoder.GetBytes(value, charStart, charsRead, buffer, charsRead == numLeft), token).ConfigureAwait(false);
}
}
}
/// <summary>
/// Encodes the string to bytes and write them to pipe asynchronously.
/// </summary>
/// <param name="writer">The pipe writer.</param>
/// <param name="value">The block of characters to encode.</param>
/// <param name="context">The text encoding context.</param>
/// <param name="bufferSize">The buffer size (in bytes) used for encoding.</param>
/// <param name="lengthFormat">String length encoding format; or <see langword="null"/> to prevent encoding of string length.</param>
/// <param name="token">The token that can be used to cancel operation.</param>
/// <returns>The result of operation.</returns>
/// <exception cref="OperationCanceledException">The operation has been canceled.</exception>
/// <exception cref="ArgumentOutOfRangeException"><paramref name="lengthFormat"/> is invalid.</exception>
/// <exception cref="EndOfStreamException">Pipe closed unexpectedly.</exception>
public static async ValueTask WriteStringAsync(this PipeWriter writer, ReadOnlyMemory <char> value, EncodingContext context, int bufferSize = 0, LengthFormat?lengthFormat = null, CancellationToken token = default)
{
var result = await writer.WriteLengthAsync(value, context.Encoding, lengthFormat, token).ConfigureAwait(false);
result.ThrowIfCancellationRequested(token);
if (value.IsEmpty)
{
return;
}
var encoder = context.GetEncoder();
for (int charsLeft = value.Length, charsUsed, maxChars, bytesPerChar = context.Encoding.GetMaxByteCount(1); charsLeft > 0; value = value.Slice(charsUsed), charsLeft -= charsUsed)
{
if (result.IsCompleted)
{
throw new EndOfStreamException();
}
var buffer = writer.GetMemory(bufferSize);
maxChars = buffer.Length / bytesPerChar;
charsUsed = Math.Min(maxChars, charsLeft);
encoder.Convert(value.Span.Slice(0, charsUsed), buffer.Span, charsUsed == charsLeft, out charsUsed, out var bytesUsed, out _);
writer.Advance(bytesUsed);
result = await writer.FlushAsync(token).ConfigureAwait(false);
result.ThrowIfCancellationRequested(token);
}
}
