async Task _WriteValueAsync(ReadOnlyMemory <byte> data, GattWriteOption option)
{
if (option == GattWriteOption.WriteWithoutResponse)
{
var(fd, mtu) = await proxy.AcquireWriteAsync(new Dictionary <string, object>());
// do low level file I/O in background task
await Task.Run(() => {
try {
using (var dataHandle = data.Pin()) {
unsafe {
var written = 0;
while (written < data.Length)
{
var ret = write((int)fd.DangerousGetHandle(), dataHandle.Pointer, (UIntPtr)data.Length);
if ((int)ret == -1)
{
var err = Marshal.GetLastWin32Error();
if (err == EINTR || err == EAGAIN)
{
continue;
}
// TODO: marshal other errors to more specific exceptions
throw new Exception($"IO error: {Marshal.PtrToStringAnsi(strerror(err))}");
}
written += (int)ret;
}
}
}
}
finally {
fd.Close();
}
});
}
else
{
if (data.Length <= 20)
{
await proxy.WriteValueAsync(data.ToArray(), new Dictionary <string, object>());
}
else
{
var options = new Dictionary <string, object> {
{ "offset", (ushort)0 }
};
for (ushort i = 0; i < data.Length; i += 20)
{
options["offset"] = i;
await proxy.WriteValueAsync(data.Slice(i, Math.Min(data.Length - i, 20)).ToArray(), options);
}
}
}
}
public Task WriteValueAsync(byte[] value)
{
return(_gattCharacteristic1Proxy.WriteValueAsync(value, new Dictionary <string, object>()));
}