bag_helper.py
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00001 # Software License Agreement (BSD License)
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00003 # Copyright (c) 2012, Willow Garage, Inc.
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00010 #  * Redistributions of source code must retain the above copyright
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00031 # POSSIBILITY OF SUCH DAMAGE.
00032 
00033 """
00034 Helper functions for bag files and timestamps.
00035 """
00036 
00037 import time
00038 import rospy
00039 
00040 
00041 def stamp_to_str(t):
00042     """
00043     Convert a rospy.Time to a human-readable string.
00044 
00045     @param t: time to convert
00046     @type  t: rospy.Time
00047     """
00048     t_sec = t.to_sec()
00049     if t < rospy.Time.from_sec(60 * 60 * 24 * 365 * 5):
00050         # Display timestamps earlier than 1975 as seconds
00051         return '%.3fs' % t_sec
00052     else:
00053         return time.strftime('%b %d %Y %H:%M:%S', time.localtime(t_sec)) + '.%03d' % (t.nsecs / 1000000)
00054 
00055 
00056 def get_topics(bag):
00057     """
00058     Get an alphabetical list of all the unique topics in the bag.
00059 
00060     @return: sorted list of topics
00061     @rtype:  list of str
00062     """
00063     return sorted(set([c.topic for c in bag._get_connections()]))
00064 
00065 
00066 def get_start_stamp(bag):
00067     """
00068     Get the earliest timestamp in the bag.
00069 
00070     @param bag: bag file
00071     @type  bag: rosbag.Bag
00072     @return: earliest timestamp
00073     @rtype:  rospy.Time
00074     """
00075     start_stamp = None
00076     for connection_start_stamp in [index[0].time for index in bag._connection_indexes.values()]:
00077         if not start_stamp or connection_start_stamp < start_stamp:
00078             start_stamp = connection_start_stamp
00079     return start_stamp
00080 
00081 
00082 def get_end_stamp(bag):
00083     """
00084     Get the latest timestamp in the bag.
00085 
00086     @param bag: bag file
00087     @type  bag: rosbag.Bag
00088     @return: latest timestamp
00089     @rtype:  rospy.Time
00090     """
00091     end_stamp = None
00092     for connection_end_stamp in [index[-1].time for index in bag._connection_indexes.values()]:
00093         if not end_stamp or connection_end_stamp > end_stamp:
00094             end_stamp = connection_end_stamp
00095 
00096     return end_stamp
00097 
00098 
00099 def get_topics_by_datatype(bag):
00100     """
00101     Get all the message types in the bag and their associated topics.
00102 
00103     @param bag: bag file
00104     @type  bag: rosbag.Bag
00105     @return: mapping from message typename to list of topics
00106     @rtype:  dict of str to list of str
00107     """
00108     topics_by_datatype = {}
00109     for c in bag._get_connections():
00110         topics_by_datatype.setdefault(c.datatype, []).append(c.topic)
00111 
00112     return topics_by_datatype
00113 
00114 
00115 def get_datatype(bag, topic):
00116     """
00117     Get the datatype of the given topic.
00118 
00119     @param bag: bag file
00120     @type  bag: rosbag.Bag
00121     @return: message typename
00122     @rtype:  str
00123     """
00124     for c in bag._get_connections(topic):
00125         return c.datatype
00126 
00127     return None


rqt_bag
Author(s): Aaron Blasdel
autogenerated on Fri Jan 3 2014 11:55:06