Source Code for Module mosp_tools.heatmap.logfilereader

 1  """Helper funtions to read log files""" 
 2   
 3  from sys import maxint 
 4  from csv import reader 
 5   
 6  __author__ = "B. Henne" 
 7  __contact__ = "henne@dcsec.uni-hannover.de" 
 8  __copyright__ = "(c) 2011, DCSec, Leibniz Universitaet Hannover, Germany" 
 9  __license__ = "GPLv3" 
10   
11   
12 -def read_simple(filename, delimiter, t, x, y): 
13      """Reads complete CSV log file with time, x-value and y-value and return only this. 
14      @author: B. Henne""" 
15      logReader = reader(open(filename), delimiter=delimiter) 
16      for row in logReader: 
17          yield row[t], [row[x], row[y]] 
18   
19 -def read(filename, delimiter, t, x, y, t_start=0, t_end=maxint, empty=[]): 
20      """Reads CSV log file with time, x-value and y-value for specified time interval.  
21      Return values for all t_start < t < t_end. 
22       
23      Times with no log entries are filled with value of empty.  
24      Returns iterable pair of time and list of coordinates 
25      @param filename: name of csv file 
26      @param delimiter: delimiter between columns in csv file 
27      @param t: number of column containing time 
28      @param x: number of column containing x-value 
29      @param y: number of column containing y-value 
30      @param t_start: start of output time interval 
31      @param t_end: end of output time interval 
32      @param empty: value yielded if no log entry exists for a time, default is empty list, maybe use None 
33      @author: B. Henne""" 
34      logReader = reader(open(filename), delimiter=delimiter) 
35      t_now = t_start                 #: current iteration time 
36      row = logReader.next()          #: list of csv file as list of columns 
37      while t_now <= t_end: 
38          dxy = [] 
39          dt = int(row[t])            #: read time 
40          dx = row[x]                 #: read x-value 
41          dy = row[y]                 #: read y-value 
42          if dt < t_start:             # read time before start: we do not want this values before start 
43              try: 
44                  row = logReader.next()  # read next and start again 
45              except: 
46                  pass 
47              continue 
48          if dt < t_now:              # read time before current iteration time 
49              yield t_now, empty 
50              t_now += 1 
51              continue 
52          if dt > t_now:              # read time is after current time 
53             yield t_now, empty         
54             t_now += 1 
55             continue 
56          while t_now == dt:          # read time is current time 
57              dxy.append([dx, dy]) 
58              try: 
59                  row = logReader.next() 
60              except: 
61                  dt = maxint 
62                  break 
63              dt = int(row[t]) 
64              dx = row[x] 
65              dy = row[y] 
66          yield t_now, dxy 
67          t_now += 1 
68   
69 -def accumulated_read(filename, delimiter, t, x, y, t_start=0, t_end=maxint, step=10): 
70      """Reads CSV file as read(), but accumulates return values in step size packets. 
71      @author: B. Henne""" 
72      acc = [] 
73      substep = 1 
74      for t, xy in read(filename, delimiter, t, x, y, t_start=t_start, t_end=t_end, empty=None): 
75          if xy is not None: 
76              acc.extend(xy) 
77          if substep % step == 0: 
78              yield t, acc 
79              acc = [] 
80              last_acc = t 
81          substep += 1 
82      if last_acc != t: 
83          yield t, acc 
84   
85   
86  if __name__ == '__main__': 
87      for t,xy in read('data/logfilereader_testdata.txt', ' ', 0, 1, 2, 0, 35): 
88          print t,xy 
89      for xy in accumulated_read('data/logfilereader_testdata.txt', ' ', 0, 1, 2, 10, 49, 10): 
90          print xy 
91