TextReader
for ReadOnlySequence<byte>
Given a ReadOnlySequence<byte>
, an adapter to progressively read it as text
can be useful. Many APIs already accept a TextReader
to read text.
Console.In
and StreamReader
are TextReader
s, for example.
The SequenceTextReader
class derives from TextReader
and accepts a
ReadOnlySequence<byte>
in order to enable reading text from a byte sequence.
You can also use the ReadOnlySequence<byte>.AsStream()
extension method to create a Stream
and pass that as an argument when constructing a new StreamReader
, but creating a StreamReader
allocates a couple of large byte[]
and char[]
arrays which make this an expensive approach,
particularly when you need to read from many unique ReadOnlySequence<byte>
instances and thus
have to repeatedly create a new StreamReader
and its own buffers each time.
SequenceTextReader
avoids these costs by optimizing for reading directly from the
ReadOnlySequence<byte>
(avoiding the Stream
intermediate adapter) and by allowing
the same SequenceTextReader
instance to be assigned different ReadOnlySequence<byte>
over time, allowing reuse of the buffers it uses internally during the decoding process.
Example
private readonly SequenceTextReader sequenceReader = new SequenceTextReader();
void PrintTextToConsole(ReadOnlySequence<byte> sequence)
{
sequenceReader.Initialize(sequence, Encoding.UTF8);
string line;
while ((line = sequenceReader.ReadLine()) != null)
{
Console.WriteLine(line);
}
}