Buffer length check in socket_write()

[bjnhur]

I think, I found a bug in adafruit_wiznet5k/adafruit_wiznet5k.py

line 724, the code already has ret variable (SOCK_SIZE check & len of buffer)

Adafruit_CircuitPython_Wiznet5k/adafruit_wiznet5k/adafruit_wiznet5k.py

Lines 724 to 727 in f00a3f7

	if len(buffer) > SOCK_SIZE:
	ret = SOCK_SIZE
	else:
	ret = len(buffer)

But, line 747, 751, didn't use this ret variable.

Adafruit_CircuitPython_Wiznet5k/adafruit_wiznet5k/adafruit_wiznet5k.py

Lines 747 to 751 in f00a3f7

	ptr = (ptr + len(buffer)) & 0xFFFF
	self._write_sntx_wr(socket_num, ptr)
	cntl_byte = 0x14 + (socket_num << 5)
	self.write(dst_addr, cntl_byte, buffer)

Need to fix? My suggestion is:

        # update sn_tx_wr to the value + data size
        ptr = (ptr + ret) & 0xFFFF # <-- use ret
        self._write_sntx_wr(socket_num, ptr)

        cntl_byte = 0x14 + (socket_num << 5)
        txbuf = buffer[:ret] # <- use ret
        self.write(dst_addr, cntl_byte, txbuf) # <- use txbuf

[brentru]

@bjnhur Would you be interested in opening a pull request? I'll take a look if you tag me.

[tekktrik]

Resolved by #42 with suggested fix!