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| 1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | 1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| 2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
| 3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
| 4 | 4 |
| 5 #ifndef MEDIA_BASE_RANGES_H_ | 5 #ifndef MEDIA_BASE_RANGES_H_ |
| 6 #define MEDIA_BASE_RANGES_H_ | 6 #define MEDIA_BASE_RANGES_H_ |
| 7 | 7 |
| 8 #include <ostream> | 8 #include <ostream> |
| 9 #include <vector> | 9 #include <vector> |
| 10 | 10 |
| 11 #include "base/basictypes.h" | 11 #include "base/basictypes.h" |
| 12 #include "base/logging.h" | 12 #include "base/logging.h" |
| 13 #include "base/time.h" | |
| 14 #include "media/base/media_export.h" | 13 #include "media/base/media_export.h" |
| 15 | 14 |
| 16 namespace media { | 15 namespace media { |
| 17 | 16 |
| 18 // Ranges allows holding an ordered list of ranges of [start,end) intervals. | 17 // Ranges allows holding an ordered list of ranges of [start,end) intervals. |
| 19 // The canonical example use-case is holding the list of ranges of buffered | 18 // The canonical example use-case is holding the list of ranges of buffered |
| 20 // bytes or times in a <video> tag. | 19 // bytes or times in a <video> tag. |
| 21 template<class T> // Endpoint type; typically a base::TimeDelta or an int64. | 20 template<class T> // Endpoint type; typically a base::TimeDelta or an int64. |
| 22 class Ranges { | 21 class Ranges { |
| 23 public: | 22 public: |
| 24 // Allow copy & assign. | 23 // Allow copy & assign. |
| 25 | 24 |
| 26 // Add (start,end) to this object, coallescing overlaps as appropriate. | 25 // Add (start,end) to this object, coallescing overlaps as appropriate. |
| 27 // Returns the number of stored ranges, post coallescing. | 26 // Returns the number of stored ranges, post coallescing. |
| 28 size_t Add(T start, T end); | 27 size_t Add(T start, T end); |
| 29 | 28 |
| 30 // Return the number of disjoint ranges. | 29 // Return the number of disjoint ranges. |
| 31 size_t size() const; | 30 size_t size() const; |
| 32 | 31 |
| 33 // Return the "i"'th range's start & end (0-based). | 32 // Return the "i"'th range's start & end (0-based). |
| 34 T start(int i) const; | 33 T start(int i) const; |
| 35 T end(int i) const; | 34 T end(int i) const; |
| 36 | 35 |
| 37 // Clear all ranges. | 36 // Clear all ranges. |
| 38 void clear(); | 37 void clear(); |
| 39 | 38 |
| 40 private: | 39 private: |
| 41 // Wrapper around DCHECK_LT allowing comparisons of operator<<'able T's. | |
| 42 void DCheckLT(const T& lhs, const T& rhs) const; | |
| 43 | |
| 44 // Disjoint, in increasing order of start. | 40 // Disjoint, in increasing order of start. |
| 45 std::vector<std::pair<T, T> > ranges_; | 41 std::vector<std::pair<T, T> > ranges_; |
| 46 }; | 42 }; |
| 47 | 43 |
| 48 ////////////////////////////////////////////////////////////////////// | 44 ////////////////////////////////////////////////////////////////////// |
| 49 // EVERYTHING BELOW HERE IS IMPLEMENTATION DETAIL!! | 45 // EVERYTHING BELOW HERE IS IMPLEMENTATION DETAIL!! |
| 50 ////////////////////////////////////////////////////////////////////// | 46 ////////////////////////////////////////////////////////////////////// |
| 51 | 47 |
| 52 template<class T> | 48 template<class T> |
| 53 size_t Ranges<T>::Add(T start, T end) { | 49 size_t Ranges<T>::Add(T start, T end) { |
| 54 if (start == end) // Nothing to be done with empty ranges. | 50 if (start == end) // Nothing to be done with empty ranges. |
| 55 return ranges_.size(); | 51 return ranges_.size(); |
| 56 | 52 |
| 57 DCheckLT(start, end); | 53 DCHECK(start < end); |
| 58 size_t i; | 54 size_t i; |
| 59 // Walk along the array of ranges until |start| is no longer larger than the | 55 // Walk along the array of ranges until |start| is no longer larger than the |
| 60 // current interval's end. | 56 // current interval's end. |
| 61 for (i = 0; i < ranges_.size() && ranges_[i].second < start; ++i) { | 57 for (i = 0; i < ranges_.size() && ranges_[i].second < start; ++i) { |
| 62 // Empty body | 58 // Empty body |
| 63 } | 59 } |
| 64 | 60 |
| 65 // Now we know |start| belongs in the i'th slot. | 61 // Now we know |start| belongs in the i'th slot. |
| 66 // If i is the end of the range, append new range and done. | 62 // If i is the end of the range, append new range and done. |
| 67 if (i == ranges_.size()) { | 63 if (i == ranges_.size()) { |
| (...skipping 24 matching lines...) Expand all Loading... |
| 92 // original loop went too far. | 88 // original loop went too far. |
| 93 while ((i + 1) < ranges_.size() && | 89 while ((i + 1) < ranges_.size() && |
| 94 ranges_[i + 1].first <= ranges_[i].second) { | 90 ranges_[i + 1].first <= ranges_[i].second) { |
| 95 ranges_[i].second = std::max(ranges_[i].second, ranges_[i + 1].second); | 91 ranges_[i].second = std::max(ranges_[i].second, ranges_[i + 1].second); |
| 96 ranges_.erase(ranges_.begin() + i + 1); | 92 ranges_.erase(ranges_.begin() + i + 1); |
| 97 } | 93 } |
| 98 | 94 |
| 99 return ranges_.size(); | 95 return ranges_.size(); |
| 100 } | 96 } |
| 101 | 97 |
| 102 template<> | |
| 103 void Ranges<base::TimeDelta>::DCheckLT(const base::TimeDelta& lhs, | |
| 104 const base::TimeDelta& rhs) const; | |
| 105 | |
| 106 template<class T> | |
| 107 void Ranges<T>::DCheckLT(const T& lhs, const T& rhs) const { | |
| 108 DCHECK_LT(lhs, rhs); | |
| 109 } | |
| 110 | |
| 111 template<class T> | 98 template<class T> |
| 112 size_t Ranges<T>::size() const { | 99 size_t Ranges<T>::size() const { |
| 113 return ranges_.size(); | 100 return ranges_.size(); |
| 114 } | 101 } |
| 115 | 102 |
| 116 template<class T> | 103 template<class T> |
| 117 T Ranges<T>::start(int i) const { | 104 T Ranges<T>::start(int i) const { |
| 118 return ranges_[i].first; | 105 return ranges_[i].first; |
| 119 } | 106 } |
| 120 | 107 |
| 121 template<class T> | 108 template<class T> |
| 122 T Ranges<T>::end(int i) const { | 109 T Ranges<T>::end(int i) const { |
| 123 return ranges_[i].second; | 110 return ranges_[i].second; |
| 124 } | 111 } |
| 125 | 112 |
| 126 template<class T> | 113 template<class T> |
| 127 void Ranges<T>::clear() { | 114 void Ranges<T>::clear() { |
| 128 ranges_.clear(); | 115 ranges_.clear(); |
| 129 } | 116 } |
| 130 | 117 |
| 131 } // namespace media | 118 } // namespace media |
| 132 | 119 |
| 133 #endif // MEDIA_BASE_RANGES_H_ | 120 #endif // MEDIA_BASE_RANGES_H_ |
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