New rtc dump analyzing tool in Python

tools/py_event_log_analyzer/misc.py

+#  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+#
+#  Use of this source code is governed by a BSD-style license
+#  that can be found in the LICENSE file in the root of the source
+#  tree. An additional intellectual property rights grant can be found
+#  in the file PATENTS.  All contributing project authors may
+#  be found in the AUTHORS file in the root of the source tree.
+
+"""Utility functions for calculating statistics.
+"""
+
+from __future__ import division
+import collections
+import sys
+
+
+def count_reordered(sequence_numbers):
+  """Returns number of indices `i` for which
+  sequence_numbers[i] >= sequence_numbers[i+1]
+  """
+  return sum(1 for (s1, s2) in zip(sequence_numbers,
+                                   sequence_numbers[1:]) if
+             s1 >= s2)
+
+
+def ssrc_normalized_size_table(data_points):
+  """Returns mapping from a SSRC to its relative occurance proportion in
+  the data.
+  """
+  d = collections.defaultdict(int)
+  for pt in data_points:
+    d[pt.ssrc] += pt.size
+  print(d)

[kwiberg-webrtc, 2016/05/31 09:04:47]

This looks like debug code.

[aleloi, 2016/05/31 09:49:48]

Removed, thank you! (I did run the code before uploading, but somehow missed
this).

+  return normalize_counter(d)
+
+
+def normalize_counter(counter):
+  """Normalizes (i.e. divides by total to sum up to 1) values in input
+  dictionary.
+
+  """
+  total = sum(counter.values())
+  for key in counter:
+    counter[key] /= total
+  return counter

[kwiberg-webrtc, 2016/05/31 09:04:47]

The standard operating procedure in Python is to either modify the argument or
return a modified value. If you do both, call sites (such as the one on line 34)
look like they don't modify the argument even though they do, which can cause
bugs later.

Given that performance probably isn't a top priority here, I'd recommend that
you make this function return a new value.

[aleloi, 2016/05/31 09:49:48]

Done.

+
+
+def unwrap(data, mod):
+  """Unwraps `data` modulo `mod`.
+
+  Adds integer multiples of mod to all elements of data except the
+  first, such that all pairs of consecutive elements (a, b) satisfy
+  -mod / 2 <= b - a < mod / 2.
+
+  E.g. unwrap([0, 1, 2, 0, 1, 2, 7, 8], 3) -> [0, 1, 2, 3,
+  4, 5, 4, 5]
+
+  """
+  for i in range(1, len(data)):
+    data[i] = (data[i - 1] +
+               (data[i] - data[i - 1] + mod // 2) % mod - mod // 2)
+  return data

[kwiberg-webrtc, 2016/05/31 09:04:47]

Here too.

[aleloi, 2016/05/31 09:49:48]

Done.

+
+# Python 2/3-compatible input function
+if sys.version_info[0] <= 2:
+  get_input = raw_input
+else:
+  get_input = input