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| 1 # Copyright (c) 2016 The WebRTC project authors. All Rights Reserved. |
| 2 # |
| 3 # Use of this source code is governed by a BSD-style license |
| 4 # that can be found in the LICENSE file in the root of the source |
| 5 # tree. An additional intellectual property rights grant can be found |
| 6 # in the file PATENTS. All contributing project authors may |
| 7 # be found in the AUTHORS file in the root of the source tree. |
| 8 |
| 9 """Utility functions for calculating statistics. |
| 10 """ |
| 11 |
| 12 from __future__ import division |
| 13 import collections |
| 14 import sys |
| 15 |
| 16 |
| 17 def count_reordered(sequence_numbers): |
| 18 """Returns number of reordered indices. |
| 19 |
| 20 A reordered index is an index `i` for which sequence_numbers[i] >= |
| 21 sequence_numbers[i + 1] |
| 22 """ |
| 23 return sum(1 for (s1, s2) in zip(sequence_numbers, |
| 24 sequence_numbers[1:]) if |
| 25 s1 >= s2) |
| 26 |
| 27 |
| 28 def ssrc_normalized_size_table(data_points): |
| 29 """Counts proportion of data for every SSRC. |
| 30 |
| 31 Args: |
| 32 data_points: list of pb_parse.DataPoint |
| 33 |
| 34 Returns: |
| 35 A dictionary mapping from every SSRC in the data points. The |
| 36 value of an SSRC `s` is the proportion of sizes of packets with |
| 37 SSRC `s` to the total size of all packets. |
| 38 |
| 39 """ |
| 40 mapping = collections.defaultdict(int) |
| 41 for point in data_points: |
| 42 mapping[point.ssrc] += point.size |
| 43 return normalize_counter(mapping) |
| 44 |
| 45 |
| 46 def normalize_counter(counter): |
| 47 """Returns a normalized version of the dictionary `counter`. |
| 48 |
| 49 Does not modify `counter`. |
| 50 |
| 51 Returns: |
| 52 A new dictionary, in which every value in `counter` |
| 53 has been divided by the total to sum up to 1. |
| 54 """ |
| 55 total = sum(counter.values()) |
| 56 return {key: counter[key] / total for key in counter} |
| 57 |
| 58 |
| 59 def unwrap(data, mod): |
| 60 """Returns `data` unwrapped modulo `mod`. Does not modify data. |
| 61 |
| 62 Adds integer multiples of mod to all elements of data except the |
| 63 first, such that all pairs of consecutive elements (a, b) satisfy |
| 64 -mod / 2 <= b - a < mod / 2. |
| 65 |
| 66 E.g. unwrap([0, 1, 2, 0, 1, 2, 7, 8], 3) -> [0, 1, 2, 3, |
| 67 4, 5, 4, 5] |
| 68 """ |
| 69 lst = data[:] |
| 70 for i in range(1, len(data)): |
| 71 lst[i] = lst[i - 1] + (lst[i] - lst[i - 1] + |
| 72 mod // 2) % mod - (mod // 2) |
| 73 return lst |
| 74 |
| 75 # Python 2/3-compatible input function |
| 76 if sys.version_info[0] <= 2: |
| 77 get_input = raw_input |
| 78 else: |
| 79 get_input = input |
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