/// <summary>
/// Read from a file descriptor
/// </summary>
/// <param name="descriptor">The descriptor ID</param>
/// <param name="buffer">The buffer</param>
/// <param name="size">The size</param>
/// <returns>The amount of bytes read</returns>
public static int Read(int descriptor, byte[] buffer, uint size)
{
FileDescriptors descriptors = Tasking.CurrentTask.FileDescriptors;
Node node = descriptors.GetNode(descriptor);
if (node == null)
{
return(-(int)ErrorCode.EBADF);
}
// Can't do read from a directory
if ((node.Flags & NodeFlags.DIRECTORY) == NodeFlags.DIRECTORY)
{
return(-(int)ErrorCode.EISDIR);
}
bool isNonBlocking = ((node.OpenFlags & O_NONBLOCK) == O_NONBLOCK);
// Wait until data is available if its blocking
if (!isNonBlocking)
{
while (VFS.GetSize(node) == 0)
{
Tasking.Yield();
}
}
// Non-blocking but no data available?
else
{
if (VFS.GetSize(node) == 0)
{
return(-(int)ErrorCode.EAGAIN);
}
}
uint offset = descriptors.GetOffset(descriptor);
uint readBytes = VFS.Read(node, offset, size, buffer);
descriptors.SetOffset(descriptor, offset + readBytes);
return((int)readBytes);
}