fast serialUSB read function readBlock

[facchinm]

Moved from arduino/Arduino#4871

sined23 commented on 15 Apr 2016
The main idea is that bytes are written and read into/from CDC buffer not one by one but block of bytes.

Serial_::accept write into CDC buffer as maximum as possible (only to not overflow the buffer)
Serial_::readb (you can change just read, not use readb) get from CDC buffer as maximum as possible or nessasary length

and one more important thing: in USBD_Recv "while (n--) *dst++ = UDD_Recv8(ep & 0xF);" should be replaced into UDD_Recv(ep & 0xF, dst, len);

[coolio986]

Hi,
I have merged this code into my own code from Arduino IDE 1.8.9 and I can confirm the code merges properly. I am testing this code using and Arduino DUE and I can confirm that it works correctly. Is it possible to merge this tot he latest base?

[CLAassistant]

All committers have signed the CLA.

[sined23]

Hi. Is it merged?