2 files changed, 193 insertions, 0 deletions

diff --git a/README b/README
index 161c94c..e1fba69 100644
--- a/README
+++ b/README
@@ -30,6 +30,7 @@ information on each of the devices.
 | LifeScan     | OneTouch Select Plus | `otverio2015`      |
 | Abbott       | FreeStyle Optium     | `freestyle_optium` |
 | Roche        | Accu-Chek Mobile     | `accuchek_reports` |
+| SD Biosensor | SD CodeFree          | `sdcodefree`       |
 
 ### Driver features
 
@@ -40,6 +41,7 @@ information on each of the devices.
 | `otverio2015`      | serialno, swver       | get and set | no                      | yes                     |
 | `freestyle_optium` | serialno, swver, unit | get and set | not supported by device | not supported by device |
 | `accuchek_reports` | serialno, unit        | no          | yes                     | not supported by device |
+| `sdcodefree`       | none                  | get         | pre-/post-meal notes    | not supported by device |
 
 ### Driver dependencies
 
@@ -49,6 +51,7 @@ information on each of the devices.
 | `otultraeasy`      | [pyserial]    |
 | `otverio2015`      | [python-scsi] |
 | `freestyle_optium` | [pyserial]    |
+| `sdcodefree`       | [pyserial]    |
 
 [pyserial]: https://pythonhosted.org/pyserial/
 [python-scsi]: https://github.com/rosjat/python-scsi
diff --git a/glucometerutils/drivers/sdcodefree.py b/glucometerutils/drivers/sdcodefree.py
new file mode 100644
index 0000000..ec232dd
--- /dev/null
+++ b/glucometerutils/drivers/sdcodefree.py
@@ -0,0 +1,190 @@
+# -*- coding: utf-8 -*-
+"""Driver for SD CodeFree devices by SD Biosensor"""
+
+__author__ = 'Diego Elio Pettenò'
+__email__ = 'flameeyes@flameeyes.eu'
+__copyright__ = 'Copyright © 2016, Diego Elio Pettenò'
+__license__ = 'MIT'
+
+import array
+import collections
+import datetime
+import functools
+import operator
+import struct
+import time
+
+import serial
+
+from glucometerutils import common
+from glucometerutils import exceptions
+
+_STX = 0x53  # Not really 'STX'
+_ETX = 0xAA  # Not really 'ETX'
+
+_DIR_IN = 0x20
+_DIR_OUT = 0x10
+
+_IDX_STX = 0
+_IDX_DIRECTION = 1
+_IDX_LENGTH = 2
+_IDX_CHECKSUM = -2
+_IDX_ETX = -1
+
+_RECV_PREAMBLE = b'\x53\x20'
+
+_CHALLENGE_PACKET_FULL = b'\x53\x20\x04\x10\x30\x20\xAA'
+_RESPONSE_PACKET = b'\x10\x40'
+
+_DATE_SET_PACKET = b'\x10\x10'
+
+_DISCONNECT_PACKET = b'\x10\x60'
+_DISCONNECTED_PACKET = b'\x10\x70'
+
+_STRUCT_READINGS_COUNT = struct.Struct('>H')
+
+_FETCH_PACKET = b'\x10\x60'
+
+_ReadingRecord = collections.namedtuple(
+  '_ReadingRecord',
+  ('unknown1', 'unknown2', 'year', 'month', 'day', 'hour', 'minute',
+   'value', 'meal_flag'))
+_STRUCT_READING = struct.Struct('>BBBBBBBHB')
+
+_MEAL_FLAG = {
+  0x00: common.NO_MEAL,
+  0x10: common.BEFORE_MEAL,
+  0x20: common.AFTER_MEAL
+}
+
+def parse_reading(msgdata):
+  return _ReadingRecord(*_STRUCT_READING.unpack_from(msgdata))
+
+def xor_checksum(msg):
+  return functools.reduce(operator.xor, msg)
+
+class Device(object):
+  def __init__(self, device):
+    self.serial_ = serial.Serial(
+      port=device, baudrate=38400, bytesize=serial.EIGHTBITS,
+      parity=serial.PARITY_NONE, stopbits=serial.STOPBITS_ONE,
+      timeout=300, xonxoff=False, rtscts=False, dsrdtr=False,
+      writeTimeout=None)
+
+  def read_packet(self):
+    preamble = self.serial_.read(3)
+    if len(preamble) != 3:
+      raise exceptione.InvalidResponse(
+        response='Expected 3 bytes, received %d' % len(preamble))
+    if preamble[0:_IDX_LENGTH] != _RECV_PREAMBLE:
+      raise exceptions.InvalidResponse(
+        response='Unexpected preamble %r' % pramble[0:_IDX_LENGTH])
+
+    msglen = preamble[_IDX_LENGTH]
+    message = self.serial_.read(msglen)
+    if len(message) != msglen:
+      raise exception.InvalidResponse(
+        response='Expected %d bytes, received %d' % (msglen, len(message)))
+    if message[_IDX_ETX] != _ETX:
+      raise exception.InvalidResponse(
+        response='Unexpected end-of-transmission byte: %02x' % message[_IDX_ETX])
+
+    # Calculate the checksum up until before the checksum itself.
+    msgdata = message[:_IDX_CHECKSUM]
+    
+    cksum = xor_checksum(msgdata)
+    if cksum != message[_IDX_CHECKSUM]:
+      raise exception.InvalidChecksum(message[_IDX_CHECKSUM], cksum)
+
+    return msgdata
+
+  def wait_and_ready(self):
+    challenge = self.serial_.read(1)
+
+    # The first packet read may have a prefixed zero, it might be a bug in the
+    # cp210x driver or device, but discard it if found.
+    if challenge == b'\0':
+      challege = self.serial_.read(1)
+      if challenge != b'\x53':
+        raise exceptions.ConnectionFailed(
+          message='Unexpected starting bytes %r' % challenge)
+
+    challenge += self.serial_.read(6)
+    
+    if challenge != _CHALLENGE_PACKET_FULL:
+      raise exceptions.ConnectionFailed(
+        message='Unexpected challenge %r' % challenge)
+
+    self.send_packet(_RESPONSE_PACKET)
+
+    # The first packet only contains the counter of how many readings are
+    # available.
+    first_packet = self.read_packet()
+    
+    count = _STRUCT_READINGS_COUNT.unpack_from(first_packet, 1)
+
+    return count[0]
+
+  def send_packet(self, msgdata):
+    packet = array.array('B')
+    packet.extend((_STX, _DIR_OUT, len(msgdata)+2))
+    packet.extend(msgdata)
+    packet.extend((xor_checksum(msgdata), _ETX))
+    self.serial_.write(packet.tobytes())
+    
+  def connect(self):
+    print("Please connect and turn on the device.")
+
+  def disconnect(self):
+    self.send_packet(_DISCONNECT_PACKET)
+    response = self.read_packet()
+    if response != _DISCONNECTED_PACKET:
+      raise exceptions.InvalidResponse(response=response)
+
+  def get_information_string(self):
+    return ('SD CodeFree glucometer\n')
+
+  def get_version(self):
+    raise NotImplementedError
+
+  def get_serial_number(self):
+    raise NotImplementedError
+
+  def get_glucose_unit(self):
+    # Device does not provide information on glucose unit.
+    return common.UNIT_MGDL
+
+  def get_datetime(self):
+    raise NotImplementedError
+
+  def set_datetime(self, date=datetime.datetime.now()):
+    setdatecmd = date.strftime('ADATE%Y%m%d%H%M').encode('ascii')
+
+    # Ignore the readings count.
+    self.wait_and_ready()
+    
+    self.send_packet(setdatecmd)
+    response = self.read_packet()
+    if response != _DATE_SET_PACKET:
+      raise exceptions.InvalidResponse(response=response)
+    
+    # The date we return should only include up to minute, unfortunately.
+    return datetime.datetime(date.year, date.month, date.day,
+                             date.hour, date.minute)
+
+  def zero_log(self):
+    raise NotmplementedError
+
+  def get_readings(self):
+    count = self.wait_and_ready()
+
+    for _ in range(count):
+      self.send_packet(_FETCH_PACKET)
+      rpkt = self.read_packet()
+
+      r = parse_reading(rpkt)
+      meal = _MEAL_FLAG[r.meal_flag]
+
+      yield common.Reading(
+        datetime.datetime(2000 + r.year, r.month, r.day, r.hour, r.minute),
+        r.value, meal=meal)