/// <summary>
/// Determines whether the stream starts with the given string.
/// </summary>
/// <returns>
/// 1: when starts with the given string, 0: when valid HTTP method, -1: otherwise
/// </returns>
private static async Task <int> startsWith(ICustomStreamReader clientStreamReader, IBufferPool bufferPool, string expectedStart, CancellationToken cancellationToken = default)
{
const int lengthToCheck = 10;
byte[] buffer = null;
try
{
if (bufferPool.BufferSize < lengthToCheck)
{
throw new Exception($"Buffer is too small. Minimum size is {lengthToCheck} bytes");
}
buffer = bufferPool.GetBuffer(bufferPool.BufferSize);
bool isExpected = true;
int i = 0;
while (i < lengthToCheck)
{
int peeked = await clientStreamReader.PeekBytesAsync(buffer, i, i, lengthToCheck - i, cancellationToken);
if (peeked <= 0)
{
return(-1);
}
peeked += i;
while (i < peeked)
{
int b = buffer[i];
if (b == ' ' && i > 2)
{
return(isExpected ? 1 : 0);
}
else
{
char ch = (char)b;
if (ch < 'A' || ch > 'z' || (ch > 'Z' && ch < 'a')) // ASCII letter
{
return(-1);
}
else if (i >= expectedStart.Length || ch != expectedStart[i])
{
isExpected = false;
}
}
i++;
}
}
// only letters
return(0);
}
finally
{
bufferPool.ReturnBuffer(buffer);
}
}
/// <summary>
/// Determines whether the stream starts with the given string.
/// </summary>
/// <param name="clientStreamReader">The client stream reader.</param>
/// <param name="expectedStart">The expected start.</param>
/// <returns>
/// 1: when starts with the given string, 0: when valid HTTP method, -1: otherwise
/// </returns>
private static async Task <int> startsWith(ICustomStreamReader clientStreamReader, IBufferPool bufferPool, int bufferSize, string expectedStart, CancellationToken cancellationToken = default)
{
int iRet = -1;
const int lengthToCheck = 10;
byte[] buffer = null;
try
{
buffer = bufferPool.GetBuffer(Math.Max(bufferSize, lengthToCheck));
int peeked = await clientStreamReader.PeekBytesAsync(buffer, 0, 0, lengthToCheck, cancellationToken);
if (peeked > 0)
{
bool isExpected = true;
for (int i = 0; i < lengthToCheck; i++)
{
int b = buffer[i];
if (b == ' ' && i > 2)
{
return(isExpected ? 1 : 0);
}
else
{
char ch = (char)b;
if (!char.IsLetter(ch))
{
return(-1);
}
else if (i >= expectedStart.Length || ch != expectedStart[i])
{
isExpected = false;
}
}
}
// only letters
iRet = isExpected ? 1 : 0;
}
}
finally
{
bufferPool.ReturnBuffer(buffer);
buffer = null;
}
return(iRet);
}
/// <summary>
/// Peeks bytes asynchronous.
/// </summary>
/// <param name="index">The index.</param>
/// <param name="cancellationToken">The cancellation token.</param>
/// <returns></returns>
Task <byte[]> ICustomStreamReader.PeekBytesAsync(int index, int size, CancellationToken cancellationToken)
{
return(baseStream.PeekBytesAsync(index, size, cancellationToken));
}
/// <summary>
/// Peeks bytes asynchronous.
/// </summary>
/// <param name="buffer">The buffer to copy.</param>
/// <param name="offset">The offset where copying.</param>
/// <param name="index">The index.</param>
/// <param name="count">The count.</param>
/// <param name="cancellationToken">The cancellation token.</param>
/// <returns></returns>
Task <int> ICustomStreamReader.PeekBytesAsync(byte[] buffer, int offset, int index, int count, CancellationToken cancellationToken)
{
return(baseStream.PeekBytesAsync(buffer, offset, index, count, cancellationToken));
}
public Task <int> PeekBytesAsync(byte[] buffer, int offset, int index, int size, CancellationToken cancellationToken = default)
{
return(reader.PeekBytesAsync(buffer, offset, index, size, cancellationToken));
}
public Task <byte[]> PeekBytesAsync(int index, int size, CancellationToken cancellationToken = default(CancellationToken))
{
return(reader.PeekBytesAsync(index, size, cancellationToken));
}
