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Unified Diff: media/base/text_ranges.cc

Issue 151103005: TextRenderer only pushes new cues downstream (Closed) Base URL: http://git.chromium.org/chromium/src.git@master
Patch Set: added text ranges utility and unit test Created 6 years, 10 months ago
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Index: media/base/text_ranges.cc
diff --git a/media/base/text_ranges.cc b/media/base/text_ranges.cc
new file mode 100644
index 0000000000000000000000000000000000000000..e7fbe82a1c391291cc03ac86b78e108346aef8ad
--- /dev/null
+++ b/media/base/text_ranges.cc
@@ -0,0 +1,145 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "media/base/text_ranges.h"
+
+#include "base/logging.h"
+
+namespace media {
+
+TextRanges::TextRanges() {
+ Flush();
+}
+
+void TextRanges::Flush() {
+ curr_range_itr_ = range_map_.end();
+}
+
+bool TextRanges::AddCue(base::TimeDelta start_time) {
+ typedef RangeMap::iterator Itr;
acolwell GONE FROM CHROMIUM 2014/02/05 19:09:36 nit: Please just use the full type below.
Matthew Heaney (Chromium) 2014/02/06 02:25:48 ack
+
+ if (curr_range_itr_ == range_map_.end()) {
+ // No is no active time range, so this is the first cue that
+ // follows a ssek.
acolwell GONE FROM CHROMIUM 2014/02/05 19:09:36 nit:s/ssek/Reset()/
Matthew Heaney (Chromium) 2014/02/06 02:25:48 Done.
+
+ if (range_map_.empty()) {
+ NewRange(start_time);
+ return true;
+ }
+
+ const Itr first_itr = range_map_.begin();
acolwell GONE FROM CHROMIUM 2014/02/05 19:09:36 nit: Inline this since it is only used on the next
Matthew Heaney (Chromium) 2014/02/06 02:25:48 Done.
+
+ if (start_time < first_itr->first) {
+ NewRange(start_time);
+ return true;
+ }
+
+ const Itr itr = --Itr(range_map_.upper_bound(start_time));
+ DCHECK(start_time >= itr->first);
+
+ Range& range = itr->second;
+
+ if (start_time > range.last_time) {
+ NewRange(start_time);
+ return true;
+ }
+
+ if (start_time < range.last_time)
+ range.count = 0;
+ else
+ range.count = 1;
+
+ curr_range_itr_ = itr;
+ return false;
+ }
+
+ DCHECK(start_time >= curr_range_itr_->first);
+
+ Range& curr_range = curr_range_itr_->second;
+
+ if (start_time < curr_range.last_time) {
acolwell GONE FROM CHROMIUM 2014/02/05 19:09:36 Please put the logic on lines 61 - 74 in a method
Matthew Heaney (Chromium) 2014/02/06 02:25:48 Done.
+ DCHECK_EQ(curr_range.count, 0);
+ return false;
+ }
+
+ if (start_time == curr_range.last_time) {
+ ++curr_range.count;
+
+ if (curr_range.count <= curr_range.max_count)
+ return false;
+
+ ++curr_range.max_count;
+ return true;
+ }
+
+ const Itr next_range_itr = ++Itr(curr_range_itr_);
+
+ if (next_range_itr != range_map_.end()) {
+ DCHECK(next_range_itr->first > curr_range.last_time);
+ DCHECK(start_time <= next_range_itr->first);
+
+ Range& next_range = next_range_itr->second;
+
+ if (start_time == next_range_itr->first) {
+ // We have walked off the curr range, and onto the next one.
+ // There is now no ambiguity about where the curr time range
+ // ends, and so we coalesce the curr and next ranges.
+
+ if (start_time < next_range.last_time)
+ next_range.count = 0;
acolwell GONE FROM CHROMIUM 2014/02/05 19:09:36 nit: This logic is duplicated. It looks like a Res
Matthew Heaney (Chromium) 2014/02/06 02:25:48 Done.
+ else
+ next_range.count = 1;
+
+ curr_range = next_range;
acolwell GONE FROM CHROMIUM 2014/02/05 19:09:36 nit: I think hiding the logic in this block in a v
Matthew Heaney (Chromium) 2014/02/06 02:25:48 Done.
+ range_map_.erase(next_range_itr);
+
+ return false;
+ }
+ }
+
+ // Either curr is the last range in the map, or there is a next
+ // range beyond the curr range, but its start time is ahead of this
+ // cue's start time. In either case, this cue becomes the new
+ // last_time for the curr range. Eventually we will see a cue whose
+ // time matches the start time of the next range, in which case we
+ // coalesce the curr and next ranges.
+
+ curr_range.last_time = start_time;
acolwell GONE FROM CHROMIUM 2014/02/05 19:09:36 nit: Place these assignments in an SetLastTime() m
Matthew Heaney (Chromium) 2014/02/06 02:25:48 Done.
+ curr_range.count = 1;
+ curr_range.max_count = 1;
+
+ return true;
+}
+
+void TextRanges::NewRange(base::TimeDelta start_time) {
+ Range range;
+ range.last_time = start_time;
acolwell GONE FROM CHROMIUM 2014/02/05 19:09:36 nit: Use the SetLastTime() method mentioned above
Matthew Heaney (Chromium) 2014/02/06 02:25:48 Done.
+ range.count = 1;
+ range.max_count = 1;
+
+ typedef RangeMap::iterator Itr;
acolwell GONE FROM CHROMIUM 2014/02/05 19:09:36 nit: Please remove the typdefs and inline since th
Matthew Heaney (Chromium) 2014/02/06 02:25:48 Done.
+ typedef std::pair<Itr, bool> Result;
+
+ Result result = range_map_.insert(std::make_pair(start_time, range));
+ DCHECK(result.second);
+
+ curr_range_itr_ = result.first;
+}
+
+int TextRanges::Present(base::TimeDelta start_time) const {
+ if (curr_range_itr_ == range_map_.end())
+ return -1;
+
+ if (start_time < curr_range_itr_->first)
+ return 0;
+
+ const Range& r = curr_range_itr_->second;
+
+ if (start_time <= r.last_time)
+ return 1;
+
+ return 0;
+}
+
+} // namespace media

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