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1 // Copyright 2014 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #ifndef MEDIA_BASE_TEXT_RANGES_H_ | |
6 #define MEDIA_BASE_TEXT_RANGES_H_ | |
7 | |
8 #include <map> | |
9 | |
10 #include "base/macros.h" | |
11 #include "base/time/time.h" | |
12 #include "media/base/media_export.h" | |
13 | |
14 namespace media { | |
15 | |
16 class MEDIA_EXPORT TextRanges { | |
17 public: | |
18 TextRanges(); | |
19 | |
20 // Reset the current range pointer, such that we bind to a new range | |
21 // (either one that exists already, or one that is freshly-created) | |
22 // during the next AddCue(). | |
23 void Reset(); | |
24 | |
25 // Given a cue with starting timestamp |start_time|, add its start | |
26 // time to the time ranges. (Note that following a Reset(), cue | |
27 // times are assumed to be monotonically increasing.) If this time | |
28 // has already been added to the time ranges, then AddCue() returns | |
29 // false and clients should not push the cue downstream. Otherwise, | |
30 // the time is added to the time ranges and AddCue() returns true, | |
31 // meaning that the cue should be pushed downstream. | |
32 bool AddCue(base::TimeDelta start_time); | |
33 | |
34 // Returns a count of the number of time ranges, intended for use by | |
35 // the unit test module to vet proper time range merge behavior. | |
36 size_t RangeCountForTesting() const; | |
37 | |
38 private: | |
39 // Describes a range of times for cues that have already been | |
40 // pushed downstream. | |
41 struct Range { | |
acolwell GONE FROM CHROMIUM
2014/02/07 01:44:18
Convert this to class. Make all the methods public
Matthew Heaney (Chromium)
2014/02/07 03:24:35
Done.
| |
42 // Initialize last_time count. | |
43 void ResetCount(base::TimeDelta start_time); | |
44 | |
45 // Set last_time and associated counts. | |
46 void SetLastTime(base::TimeDelta start_time); | |
47 | |
48 // Adjust time range state to mark the cue as having been seen, | |
49 // returning true if we have not seen |start_time| already and | |
50 // false otherwise. | |
51 bool AddCue(base::TimeDelta start_time); | |
52 | |
53 // The last timestamp of this range. | |
54 base::TimeDelta last_time; | |
55 | |
56 // The number of cues we have detected so far, for this range, | |
57 // whose timestamp matches last_time. | |
58 int max_count; | |
59 | |
60 // The number of cues we have seen since the most recent Reset(), | |
61 // whose timestamp matches last_time. | |
62 int count; | |
63 }; | |
64 | |
65 typedef std::map<base::TimeDelta, Range> RangeMap; | |
66 | |
67 // NewRange() is used to create a new time range when AddCue() is | |
68 // called immediately following a Reset(), and no existing time | |
69 // range contains the indicated |start_time| of the cue. | |
70 void NewRange(base::TimeDelta start_time); | |
71 | |
72 // Coalesce curr_range with the range that immediately follows. | |
73 void Merge(Range& curr_range, RangeMap::iterator next_range_itr); | |
74 | |
75 // The collection of time ranges, each of which is bounded | |
76 // (inclusive) by the key and Range::last_time. | |
77 RangeMap range_map_; | |
78 | |
79 // The time range to which we bind following a Reset(). | |
80 RangeMap::iterator curr_range_itr_; | |
81 | |
82 DISALLOW_COPY_AND_ASSIGN(TextRanges); | |
83 }; | |
84 | |
85 } // namespace media | |
86 | |
87 #endif // MEDIA_BASE_TEXT_RANGES_H_ | |
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