Add Python 3 support

CMakeLists.txt

@@ -6,9 +6,9 @@ find_package(catkin REQUIRED COMPONENTS roslint)
 catkin_python_setup()
 catkin_package()
 
-install(PROGRAMS
-   scripts/nmea_tcp_driver
-   DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION}
+catkin_install_python(PROGRAMS
+  scripts/nmea_tcp_driver
+  DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION}
 )
 
 # Check package for pep8 style, add a test to fail on violations.

scripts/nmea_tcp_driver

@@ -106,7 +106,7 @@ class ReachSocketHandler:
     # Also set a timeout so we can make sure we have a valid socket
     # https://stackoverflow.com/a/15175067
     def buffered_readLine(self):
-        line = ""
+        line = b""
         while not rospy.is_shutdown():
             # Try to get data from it
             try:
@@ -118,9 +118,9 @@ class ReachSocketHandler:
             if not part or len(part) == 0:
                 self.reconnect_to_device()
                 continue
-            if part != "\n":
+            if part != b"\n":
                 line += part
-            elif part == "\n":
+            elif part == b"\n":
                 break
         return line
 

src/reach_ros_node/checksum_utils.py

@@ -33,7 +33,7 @@
 
 # Check the NMEA sentence checksum. Return True if passes and False if failed
 def check_nmea_checksum(nmea_sentence):
-    split_sentence = nmea_sentence.split('*')
+    split_sentence = nmea_sentence.split(b'*')
     if len(split_sentence) != 2:
         #No checksum bytes were found... improperly formatted/incomplete NMEA data?
         return False
@@ -43,6 +43,9 @@ def check_nmea_checksum(nmea_sentence):
     data_to_checksum = split_sentence[0][1:]
     checksum = 0
     for c in data_to_checksum:
-        checksum ^= ord(c)
+        if type(c) is int:
+            checksum ^= c
+        else:
+            checksum ^= ord(c)
 
-    return ("%02X" % checksum) == transmitted_checksum.upper()
+    return (b"%02X" % checksum) == transmitted_checksum.upper()

src/reach_ros_node/driver.py

@@ -113,13 +113,13 @@ def process_line(self, nmea_string):
     # Parses the GGA NMEA message type
     def parse_GGA(self,datag):
         # Check if we should parse this message
-        if not 'GGA' in datag:
+        if not b'GGA' in datag:
             return
         # Return if are using RCm
         if self.use_rmc:
             return
         # Else lets set what variables we can
-        data = datag['GGA']
+        data = datag[b'GGA']
         # If using ROS time, use the current timestamp
         if self.use_rostime:
             self.msg_fix.header.stamp = rospy.get_rostime()
@@ -159,13 +159,13 @@ def parse_GGA(self,datag):
     # Parses the GST NMEA message type
     def parse_GST(self,datag):
         # Check if we should parse this message
-        if not 'GST' in datag:
+        if not b'GST' in datag:
             return
         # Return if are using RCM
         if self.use_rmc:
             return
         # Else lets set what variables we can
-        data = datag['GST']
+        data = datag[b'GST']
         # Update the fix message with std
         self.msg_fix.position_covariance[0] = pow(data['latitude_sigma'],2)
         self.msg_fix.position_covariance[4] = pow(data['longitude_sigma'],2)
@@ -179,13 +179,13 @@ def parse_GST(self,datag):
     # Parses the VTG NMEA message type
     def parse_VTG(self,datag):
         # Check if we should parse this message
-        if not 'VTG' in datag:
+        if not b'VTG' in datag:
             return
         # Return if are using RCM
         if self.use_rmc:
             return
         # Else lets set what variables we can
-        data = datag['VTG']
+        data = datag[b'VTG']
         # Next lets publish the velocity we have
         # If using ROS time, use the current timestamp
         # Else this message doesn't provide a time, so just set to zero
@@ -206,13 +206,13 @@ def parse_VTG(self,datag):
     # Parses the RMC NMEA message type
     def parse_RMC(self,datag):
         # Check if we should parse this message
-        if not 'RMC' in datag:
+        if not b'RMC' in datag:
             return
         # Return if not using RCM
         if not self.use_rmc:
             return
         # Else lets set what variables we can
-        data = datag['RMC']
+        data = datag[b'RMC']
         # If using ROS time, use the current timestamp
         if self.use_rostime:
             self.msg_fix.header.stamp = rospy.get_rostime()
@@ -260,10 +260,10 @@ def parse_RMC(self,datag):
     def parse_time(self,datag):
 
         # Get our message data
-        if not self.use_rmc and 'GGA' in datag:
-            data = datag['GGA']
-        elif self.use_rmc and 'RMC' in datag:
-            data = datag['RMC']
+        if not self.use_rmc and b'GGA' in datag:
+            data = datag[b'GGA']
+        elif self.use_rmc and b'RMC' in datag:
+            data = datag[b'RMC']
         else:
             return
         # Return if time is NaN

src/reach_ros_node/parser.py

@@ -118,7 +118,7 @@ def convert_deg_to_rads(degs):
 https://www.sparkfun.com/datasheets/GPS/NMEA%20Reference%20Manual1.pdf
 """
 parse_maps = {
-    "GGA": [
+    b"GGA": [
         ("utc_time", convert_time, 1),
         ("latitude", convert_latitude, 2),
         ("latitude_direction", str, 3),
@@ -130,7 +130,7 @@ def convert_deg_to_rads(degs):
         ("altitude", safe_float, 9),
         ("mean_sea_level", safe_float, 11),
         ],
-    "GST": [
+    b"GST": [
         ("utc_time", convert_time, 1),
         ("ellipse_sigma_major", safe_float, 3),
         ("ellipse_sigma_minor", safe_float, 4),
@@ -139,7 +139,7 @@ def convert_deg_to_rads(degs):
         ("longitude_sigma", safe_float, 7),
         ("altitude_sigma", safe_float, 8),
         ],
-    "RMC": [
+    b"RMC": [
         ("utc_time", convert_time, 1),
         ("fix_valid", convert_status_flag, 2),
         ("latitude", convert_latitude, 3),
@@ -149,12 +149,12 @@ def convert_deg_to_rads(degs):
         ("speed", convert_knots_to_mps, 7),
         ("true_course", convert_deg_to_rads, 8),
         ],
-    "VTG": [
+    b"VTG": [
         ("ori_true", convert_deg_to_rads, 1),
         ("ori_magnetic", convert_deg_to_rads, 3),
         ("speed", convert_knots_to_mps, 5),
         ],
-    "GSV": [
+    b"GSV": [
         ("message_total", safe_int, 1),
         ("message_number", safe_int, 2),
         ("sat_in_view", safe_int, 3),
@@ -175,7 +175,7 @@ def convert_deg_to_rads(degs):
         ("sat_04_azimuth", convert_deg_to_rads, 18),
         ("sat_04_snr", safe_float, 19),
         ],
-    "GSA": [
+    b"GSA": [
         ("mode", str, 1),
         ("fix_type", safe_int, 2),
         ("sat_id", safe_int, 3),
@@ -188,15 +188,15 @@ def convert_deg_to_rads(degs):
 
 def parse_nmea_sentence(nmea_sentence):
     # Check for a valid nmea sentence
-    if not re.match('(^\$GP|^\$GA|^\$GN|^\$GL).*\*[0-9A-Fa-f]{2}$', nmea_sentence):
+    if not re.match(b'(^\$GP|^\$GA|^\$GN|^\$GL).*\*[0-9A-Fa-f]{2}$', nmea_sentence):
         logger.warn("Regex didn't match, sentence not valid NMEA? Sentence was: %s" % repr(nmea_sentence))
         return False
 
     # Remove the last bit after the asterisk, this is the checksum
-    nmea_sentence = nmea_sentence.split("*",1)[0]
+    nmea_sentence = nmea_sentence.split(b"*",1)[0]
 
     # Split on the commas
-    fields = [field.strip(',') for field in nmea_sentence.split(',')]
+    fields = [field.strip(b',') for field in nmea_sentence.split(b',')]
 
     # Ignore the $ and talker ID portions (e.g. GP, GL, GA, GN)
     sentence_type = fields[0][3:]