PushbackStream
using System;
using System.IO;
using System.Runtime.CompilerServices;
using System.Threading;
using System.Threading.Tasks;
namespace Org.BouncyCastle.Utilities.IO
{
public class PushbackStream : FilterStream
{
private int m_buf = -1;
public PushbackStream(Stream s)
: base(s)
{
}
[AsyncStateMachine(typeof(<CopyToAsync>d__2))]
public override Task CopyToAsync(Stream destination, int bufferSize, CancellationToken cancellationToken)
{
<CopyToAsync>d__2 stateMachine = default(<CopyToAsync>d__2);
stateMachine.<>t__builder = AsyncTaskMethodBuilder.Create();
stateMachine.<>4__this = this;
stateMachine.destination = destination;
stateMachine.bufferSize = bufferSize;
stateMachine.cancellationToken = cancellationToken;
stateMachine.<>1__state = -1;
stateMachine.<>t__builder.Start(ref stateMachine);
return stateMachine.<>t__builder.Task;
}
public override int Read(byte[] buffer, int offset, int count)
{
Streams.ValidateBufferArguments(buffer, offset, count);
if (m_buf != -1) {
if (count < 1)
return 0;
buffer[offset] = (byte)m_buf;
m_buf = -1;
return 1;
}
return s.Read(buffer, offset, count);
}
public override int ReadByte()
{
if (m_buf != -1) {
int buf = m_buf;
m_buf = -1;
return buf;
}
return s.ReadByte();
}
public virtual void Unread(int b)
{
if (m_buf != -1)
throw new InvalidOperationException("Can only push back one byte");
m_buf = (b & 255);
}
}
}