public static ValueTask <BucketBytes> PollAsync(this Bucket bucket, int minRequested = 1)
{
if (bucket is null)
{
throw new ArgumentNullException(nameof(bucket));
}
if (bucket is IBucketPoll bp)
{
return(bp.PollAsync(minRequested));
}
else
{
return(new ValueTask <BucketBytes>(bucket.Peek()));
}
}
public static async ValueTask <BucketPollBytes> PollReadAsync(this Bucket bucket, int minRequested = 1)
{
if (bucket is null)
{
throw new ArgumentNullException(nameof(bucket));
}
BucketBytes data;
if (bucket is IBucketPoll bucketPoll)
{
data = await bucketPoll.PollAsync(minRequested).ConfigureAwait(false);
if (!data.IsEmpty || data.IsEof)
{
return(new BucketPollBytes(bucket, data, 0));
}
}
else
{
data = bucket.Peek();
}
if (data.Length >= minRequested)
{
return(new BucketPollBytes(bucket, data, 0)); // Nice peek, move along
}
data = await bucket.ReadAsync(minRequested).ConfigureAwait(false);
if (data.IsEmpty)
{
return(new BucketPollBytes(bucket, BucketBytes.Eof, 0)); // Nothing to optimize
}
byte byte0 = data[0];
byte[]? dataBytes = (data.Length > 0) ? data.ToArray() : null;
int alreadyRead = data.Length;
// Now the special trick, we might just have triggered a much longer read and in
// that case we want to provide more data
data = bucket.Peek();
var(arr, offset) = data;
if (arr is not null && offset > alreadyRead)
{
if ((alreadyRead == 1 && arr[offset - 1] == byte0) ||
arr.Skip(offset - alreadyRead).Take(alreadyRead).SequenceEqual(dataBytes !))
{
// The very lucky, but common case. The peek buffer starts with what we already read
return(new BucketPollBytes(bucket, new BucketBytes(arr, offset - alreadyRead, data.Length + alreadyRead), alreadyRead));
}
}
if (data.Length > 0)
{
// We have original data and peeked data. Let's copy some data to help our caller
byte[] result = new byte[alreadyRead + data.Length];
if (alreadyRead == 1)
{
result[0] = byte0;
}
else
{
dataBytes !.CopyTo(result, 0);
}
data.CopyTo(result, alreadyRead);
dataBytes = result;
}
else if (dataBytes == null)
{
dataBytes = new[] { byte0 }
}
;
return(new BucketPollBytes(bucket, dataBytes, alreadyRead));
}