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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef INTERVALS_H
+#define INTERVALS_H
+
+#include <algorithm>
+#include "mozilla/TypeTraits.h"
+#include "nsTArray.h"
+
+// Specialization for nsTArray CopyChooser.
+namespace mozilla {
+namespace media {
+template<class T>
+class IntervalSet;
+} // namespace media
+} // namespace mozilla
+
+template<class E>
+struct nsTArray_CopyChooser<mozilla::media::IntervalSet<E>>
+{
+ typedef nsTArray_CopyWithConstructors<mozilla::media::IntervalSet<E>> Type;
+};
+
+namespace mozilla {
+namespace media {
+
+/* Interval defines an interval between two points. Unlike a traditional
+ interval [A,B] where A <= x <= B, the upper boundary B is exclusive: A <= x < B
+ (e.g [A,B[ or [A,B) depending on where you're living)
+ It provides basic interval arithmetic and fuzzy edges.
+ The type T must provides a default constructor and +, -, <, <= and ==
+ operators.
+ */
+template<typename T>
+class Interval
+{
+public:
+ typedef Interval<T> SelfType;
+
+ Interval()
+ : mStart(T())
+ , mEnd(T())
+ , mFuzz(T())
+ { }
+
+ template<typename StartArg, typename EndArg>
+ Interval(StartArg&& aStart, EndArg&& aEnd)
+ : mStart(Forward<StartArg>(aStart))
+ , mEnd(Forward<EndArg>(aEnd))
+ , mFuzz()
+ {
+ MOZ_ASSERT(aStart <= aEnd);
+ }
+
+ template<typename StartArg, typename EndArg, typename FuzzArg>
+ Interval(StartArg&& aStart, EndArg&& aEnd, FuzzArg&& aFuzz)
+ : mStart(Forward<StartArg>(aStart))
+ , mEnd(Forward<EndArg>(aEnd))
+ , mFuzz(Forward<FuzzArg>(aFuzz))
+ {
+ MOZ_ASSERT(aStart <= aEnd);
+ }
+
+ Interval(const SelfType& aOther)
+ : mStart(aOther.mStart)
+ , mEnd(aOther.mEnd)
+ , mFuzz(aOther.mFuzz)
+ { }
+
+ Interval(SelfType&& aOther)
+ : mStart(Move(aOther.mStart))
+ , mEnd(Move(aOther.mEnd))
+ , mFuzz(Move(aOther.mFuzz))
+ { }
+
+ SelfType& operator= (const SelfType& aOther)
+ {
+ mStart = aOther.mStart;
+ mEnd = aOther.mEnd;
+ mFuzz = aOther.mFuzz;
+ return *this;
+ }
+
+ SelfType& operator= (SelfType&& aOther)
+ {
+ MOZ_ASSERT(&aOther != this, "self-moves are prohibited");
+ this->~Interval();
+ new(this) Interval(Move(aOther));
+ return *this;
+ }
+
+ // Basic interval arithmetic operator definition.
+ SelfType operator+ (const SelfType& aOther) const
+ {
+ return SelfType(mStart + aOther.mStart,
+ mEnd + aOther.mEnd,
+ mFuzz + aOther.mFuzz);
+ }
+
+ // Basic interval arithmetic operator definition.
+ SelfType operator- (const SelfType& aOther) const
+ {
+ return SelfType(mStart - aOther.mEnd,
+ mEnd - aOther.mStart,
+ mFuzz + aOther.mFuzz);
+ }
+
+ bool operator== (const SelfType& aOther) const
+ {
+ return mStart == aOther.mStart && mEnd == aOther.mEnd;
+ }
+
+ bool operator!= (const SelfType& aOther) const
+ {
+ return !(*this == aOther);
+ }
+
+ bool Contains(const T& aX) const
+ {
+ return mStart - mFuzz <= aX && aX < mEnd + mFuzz;
+ }
+
+ bool ContainsStrict(const T& aX) const
+ {
+ return mStart <= aX && aX < mEnd;
+ }
+
+ bool ContainsWithStrictEnd(const T& aX) const
+ {
+ return mStart - mFuzz <= aX && aX < mEnd;
+ }
+
+ bool Contains(const SelfType& aOther) const
+ {
+ return (mStart - mFuzz <= aOther.mStart + aOther.mFuzz)
+ && (aOther.mEnd - aOther.mFuzz <= mEnd + mFuzz);
+ }
+
+ bool ContainsStrict(const SelfType& aOther) const
+ {
+ return mStart <= aOther.mStart && aOther.mEnd <= mEnd;
+ }
+
+ bool ContainsWithStrictEnd(const SelfType& aOther) const
+ {
+ return (mStart - mFuzz <= aOther.mStart + aOther.mFuzz)
+ && aOther.mEnd <= mEnd;
+ }
+
+ bool Intersects(const SelfType& aOther) const
+ {
+ return (mStart - mFuzz < aOther.mEnd + aOther.mFuzz)
+ && (aOther.mStart - aOther.mFuzz < mEnd + mFuzz);
+ }
+
+ bool IntersectsStrict(const SelfType& aOther) const
+ {
+ return mStart < aOther.mEnd && aOther.mStart < mEnd;
+ }
+
+ // Same as Intersects, but including the boundaries.
+ bool Touches(const SelfType& aOther) const
+ {
+ return (mStart - mFuzz <= aOther.mEnd + aOther.mFuzz)
+ && (aOther.mStart - aOther.mFuzz <= mEnd + mFuzz);
+ }
+
+ // Returns true if aOther is strictly to the right of this and contiguous.
+ // This operation isn't commutative.
+ bool Contiguous(const SelfType& aOther) const
+ {
+ return mEnd <= aOther.mStart && aOther.mStart - mEnd <= mFuzz + aOther.mFuzz;
+ }
+
+ bool RightOf(const SelfType& aOther) const
+ {
+ return aOther.mEnd - aOther.mFuzz <= mStart + mFuzz;
+ }
+
+ bool LeftOf(const SelfType& aOther) const
+ {
+ return mEnd - mFuzz <= aOther.mStart + aOther.mFuzz;
+ }
+
+ SelfType Span(const SelfType& aOther) const
+ {
+ if (IsEmpty()) {
+ return aOther;
+ }
+ SelfType result(*this);
+ if (aOther.mStart < mStart) {
+ result.mStart = aOther.mStart;
+ }
+ if (mEnd < aOther.mEnd) {
+ result.mEnd = aOther.mEnd;
+ }
+ if (mFuzz < aOther.mFuzz) {
+ result.mFuzz = aOther.mFuzz;
+ }
+ return result;
+ }
+
+ SelfType Intersection(const SelfType& aOther) const
+ {
+ const T& s = std::max(mStart, aOther.mStart);
+ const T& e = std::min(mEnd, aOther.mEnd);
+ const T& f = std::max(mFuzz, aOther.mFuzz);
+ if (s < e) {
+ return SelfType(s, e, f);
+ }
+ // Return an empty interval.
+ return SelfType();
+ }
+
+ T Length() const
+ {
+ return mEnd - mStart;
+ }
+
+ bool IsEmpty() const
+ {
+ return mStart == mEnd;
+ }
+
+ void SetFuzz(const T& aFuzz)
+ {
+ mFuzz = aFuzz;
+ }
+
+ // Returns true if the two intervals intersect with this being on the right
+ // of aOther
+ bool TouchesOnRight(const SelfType& aOther) const
+ {
+ return aOther.mStart <= mStart
+ && (mStart - mFuzz <= aOther.mEnd + aOther.mFuzz)
+ && (aOther.mStart - aOther.mFuzz <= mEnd + mFuzz);
+ }
+
+ T mStart;
+ T mEnd;
+ T mFuzz;
+
+private:
+};
+
+// An IntervalSet in a collection of Intervals. The IntervalSet is always
+// normalized.
+template<typename T>
+class IntervalSet
+{
+public:
+ typedef IntervalSet<T> SelfType;
+ typedef Interval<T> ElemType;
+ typedef AutoTArray<ElemType,4> ContainerType;
+ typedef typename ContainerType::index_type IndexType;
+
+ IntervalSet()
+ {
+ }
+ virtual ~IntervalSet()
+ {
+ }
+
+ IntervalSet(const SelfType& aOther)
+ : mIntervals(aOther.mIntervals)
+ {
+ }
+
+ IntervalSet(SelfType&& aOther)
+ {
+ mIntervals.AppendElements(Move(aOther.mIntervals));
+ }
+
+ explicit IntervalSet(const ElemType& aOther)
+ {
+ if (!aOther.IsEmpty()) {
+ mIntervals.AppendElement(aOther);
+ }
+ }
+
+ explicit IntervalSet(ElemType&& aOther)
+ {
+ if (!aOther.IsEmpty()) {
+ mIntervals.AppendElement(Move(aOther));
+ }
+ }
+
+ bool operator== (const SelfType& aOther) const
+ {
+ return mIntervals == aOther.mIntervals;
+ }
+
+ bool operator!= (const SelfType& aOther) const
+ {
+ return mIntervals != aOther.mIntervals;
+ }
+
+ SelfType& operator= (const SelfType& aOther)
+ {
+ mIntervals = aOther.mIntervals;
+ return *this;
+ }
+
+ SelfType& operator= (SelfType&& aOther)
+ {
+ MOZ_ASSERT(&aOther != this, "self-moves are prohibited");
+ this->~IntervalSet();
+ new(this) IntervalSet(Move(aOther));
+ return *this;
+ }
+
+ SelfType& operator= (const ElemType& aInterval)
+ {
+ mIntervals.Clear();
+ if (!aInterval.IsEmpty()) {
+ mIntervals.AppendElement(aInterval);
+ }
+ return *this;
+ }
+
+ SelfType& operator= (ElemType&& aInterval)
+ {
+ mIntervals.Clear();
+ if (!aInterval.IsEmpty()) {
+ mIntervals.AppendElement(Move(aInterval));
+ }
+ return *this;
+ }
+
+ SelfType& Add(const SelfType& aIntervals)
+ {
+ mIntervals.AppendElements(aIntervals.mIntervals);
+ Normalize();
+ return *this;
+ }
+
+ SelfType& Add(const ElemType& aInterval)
+ {
+ if (aInterval.IsEmpty()) {
+ return *this;
+ }
+ if (mIntervals.IsEmpty()) {
+ mIntervals.AppendElement(aInterval);
+ return *this;
+ }
+ ElemType& last = mIntervals.LastElement();
+ if (aInterval.TouchesOnRight(last)) {
+ last = last.Span(aInterval);
+ return *this;
+ }
+ // Most of our actual usage is adding an interval that will be outside the
+ // range. We can speed up normalization here.
+ if (aInterval.RightOf(last)) {
+ mIntervals.AppendElement(aInterval);
+ return *this;
+ }
+
+ ContainerType normalized;
+ ElemType current(aInterval);
+ IndexType i = 0;
+ for (; i < mIntervals.Length(); i++) {
+ ElemType& interval = mIntervals[i];
+ if (current.Touches(interval)) {
+ current = current.Span(interval);
+ } else if (current.LeftOf(interval)) {
+ break;
+ } else {
+ normalized.AppendElement(Move(interval));
+ }
+ }
+ normalized.AppendElement(Move(current));
+ for (; i < mIntervals.Length(); i++) {
+ normalized.AppendElement(Move(mIntervals[i]));
+ }
+ mIntervals.Clear();
+ mIntervals.AppendElements(Move(normalized));
+
+ return *this;
+ }
+
+ SelfType& operator+= (const SelfType& aIntervals)
+ {
+ Add(aIntervals);
+ return *this;
+ }
+
+ SelfType& operator+= (const ElemType& aInterval)
+ {
+ Add(aInterval);
+ return *this;
+ }
+
+ SelfType operator+ (const SelfType& aIntervals) const
+ {
+ SelfType intervals(*this);
+ intervals.Add(aIntervals);
+ return intervals;
+ }
+
+ SelfType operator+ (const ElemType& aInterval) const
+ {
+ SelfType intervals(*this);
+ intervals.Add(aInterval);
+ return intervals;
+ }
+
+ friend SelfType operator+ (const ElemType& aInterval,
+ const SelfType& aIntervals)
+ {
+ SelfType intervals;
+ intervals.Add(aInterval);
+ intervals.Add(aIntervals);
+ return intervals;
+ }
+
+ // Excludes an interval from an IntervalSet.
+ // This is done by inverting aInterval within the bounds of mIntervals
+ // and then doing the intersection.
+ SelfType& operator-= (const ElemType& aInterval)
+ {
+ if (aInterval.IsEmpty() || mIntervals.IsEmpty()) {
+ return *this;
+ }
+ T firstEnd = std::max(mIntervals[0].mStart, aInterval.mStart);
+ T secondStart = std::min(mIntervals.LastElement().mEnd, aInterval.mEnd);
+ ElemType startInterval(mIntervals[0].mStart, firstEnd);
+ ElemType endInterval(secondStart, mIntervals.LastElement().mEnd);
+ SelfType intervals(Move(startInterval));
+ intervals += Move(endInterval);
+ return Intersection(intervals);
+ }
+
+ SelfType& operator-= (const SelfType& aIntervals)
+ {
+ for (const auto& interval : aIntervals.mIntervals) {
+ *this -= interval;
+ }
+ return *this;
+ }
+
+ SelfType operator- (const SelfType& aInterval) const
+ {
+ SelfType intervals(*this);
+ intervals -= aInterval;
+ return intervals;
+ }
+
+ SelfType operator- (const ElemType& aInterval) const
+ {
+ SelfType intervals(*this);
+ intervals -= aInterval;
+ return intervals;
+ }
+
+ // Mutate this IntervalSet to be the union of this and aOther.
+ SelfType& Union(const SelfType& aOther)
+ {
+ Add(aOther);
+ return *this;
+ }
+
+ SelfType& Union(const ElemType& aInterval)
+ {
+ Add(aInterval);
+ return *this;
+ }
+
+ // Mutate this TimeRange to be the intersection of this and aOther.
+ SelfType& Intersection(const SelfType& aOther)
+ {
+ ContainerType intersection;
+
+ const ContainerType& other = aOther.mIntervals;
+ IndexType i = 0, j = 0;
+ for (; i < mIntervals.Length() && j < other.Length();) {
+ if (mIntervals[i].IntersectsStrict(other[j])) {
+ intersection.AppendElement(mIntervals[i].Intersection(other[j]));
+ }
+ if (mIntervals[i].mEnd < other[j].mEnd) {
+ i++;
+ } else {
+ j++;
+ }
+ }
+ mIntervals.Clear();
+ mIntervals.AppendElements(Move(intersection));
+ return *this;
+ }
+
+ SelfType& Intersection(const ElemType& aInterval)
+ {
+ SelfType intervals(aInterval);
+ return Intersection(intervals);
+ }
+
+ const ElemType& operator[] (IndexType aIndex) const
+ {
+ return mIntervals[aIndex];
+ }
+
+ // Returns the start boundary of the first interval. Or a default constructed
+ // T if IntervalSet is empty (and aExists if provided will be set to false).
+ T GetStart(bool* aExists = nullptr) const
+ {
+ bool exists = !mIntervals.IsEmpty();
+
+ if (aExists) {
+ *aExists = exists;
+ }
+
+ if (exists) {
+ return mIntervals[0].mStart;
+ } else {
+ return T();
+ }
+ }
+
+ // Returns the end boundary of the last interval. Or a default constructed T
+ // if IntervalSet is empty (and aExists if provided will be set to false).
+ T GetEnd(bool* aExists = nullptr) const
+ {
+ bool exists = !mIntervals.IsEmpty();
+ if (aExists) {
+ *aExists = exists;
+ }
+
+ if (exists) {
+ return mIntervals.LastElement().mEnd;
+ } else {
+ return T();
+ }
+ }
+
+ IndexType Length() const
+ {
+ return mIntervals.Length();
+ }
+
+ T Start(IndexType aIndex) const
+ {
+ return mIntervals[aIndex].mStart;
+ }
+
+ T Start(IndexType aIndex, bool& aExists) const
+ {
+ aExists = aIndex < mIntervals.Length();
+
+ if (aExists) {
+ return mIntervals[aIndex].mStart;
+ } else {
+ return T();
+ }
+ }
+
+ T End(IndexType aIndex) const
+ {
+ return mIntervals[aIndex].mEnd;
+ }
+
+ T End(IndexType aIndex, bool& aExists) const
+ {
+ aExists = aIndex < mIntervals.Length();
+
+ if (aExists) {
+ return mIntervals[aIndex].mEnd;
+ } else {
+ return T();
+ }
+ }
+
+ bool Contains(const ElemType& aInterval) const
+ {
+ for (const auto& interval : mIntervals) {
+ if (interval.Contains(aInterval)) {
+ return true;
+ }
+ }
+ return false;
+ }
+
+ bool ContainsStrict(const ElemType& aInterval) const
+ {
+ for (const auto& interval : mIntervals) {
+ if (interval.ContainsStrict(aInterval)) {
+ return true;
+ }
+ }
+ return false;
+ }
+
+ bool Contains(const T& aX) const
+ {
+ for (const auto& interval : mIntervals)
+ {
+ if (interval.Contains(aX)) {
+ return true;
+ }
+ }
+ return false;
+ }
+
+ bool ContainsStrict(const T& aX) const
+ {
+ for (const auto& interval : mIntervals) {
+ if (interval.ContainsStrict(aX)) {
+ return true;
+ }
+ }
+ return false;
+ }
+
+ bool ContainsWithStrictEnd(const T& aX) const
+ {
+ for (const auto& interval : mIntervals) {
+ if (interval.ContainsWithStrictEnd(aX)) {
+ return true;
+ }
+ }
+ return false;
+ }
+
+ // Shift all values by aOffset.
+ SelfType& Shift(const T& aOffset)
+ {
+ for (auto& interval : mIntervals) {
+ interval.mStart = interval.mStart + aOffset;
+ interval.mEnd = interval.mEnd + aOffset;
+ }
+ return *this;
+ }
+
+ void SetFuzz(const T& aFuzz)
+ {
+ for (auto& interval : mIntervals) {
+ interval.SetFuzz(aFuzz);
+ }
+ Normalize();
+ }
+
+ static const IndexType NoIndex = IndexType(-1);
+
+ IndexType Find(const T& aValue) const
+ {
+ for (IndexType i = 0; i < mIntervals.Length(); i++) {
+ if (mIntervals[i].Contains(aValue)) {
+ return i;
+ }
+ }
+ return NoIndex;
+ }
+
+ // Methods for range-based for loops.
+ typename ContainerType::iterator begin()
+ {
+ return mIntervals.begin();
+ }
+
+ typename ContainerType::const_iterator begin() const
+ {
+ return mIntervals.begin();
+ }
+
+ typename ContainerType::iterator end()
+ {
+ return mIntervals.end();
+ }
+
+ typename ContainerType::const_iterator end() const
+ {
+ return mIntervals.end();
+ }
+
+ ElemType& LastInterval()
+ {
+ MOZ_ASSERT(!mIntervals.IsEmpty());
+ return mIntervals.LastElement();
+ }
+
+ const ElemType& LastInterval() const
+ {
+ MOZ_ASSERT(!mIntervals.IsEmpty());
+ return mIntervals.LastElement();
+ }
+
+ void Clear()
+ {
+ mIntervals.Clear();
+ }
+
+protected:
+ ContainerType mIntervals;
+
+private:
+ void Normalize()
+ {
+ if (mIntervals.Length() >= 2) {
+ ContainerType normalized;
+
+ mIntervals.Sort(CompareIntervals());
+
+ // This merges the intervals.
+ ElemType current(mIntervals[0]);
+ for (IndexType i = 1; i < mIntervals.Length(); i++) {
+ ElemType& interval = mIntervals[i];
+ if (current.Touches(interval)) {
+ current = current.Span(interval);
+ } else {
+ normalized.AppendElement(Move(current));
+ current = Move(interval);
+ }
+ }
+ normalized.AppendElement(Move(current));
+
+ mIntervals.Clear();
+ mIntervals.AppendElements(Move(normalized));
+ }
+ }
+
+ struct CompareIntervals
+ {
+ bool Equals(const ElemType& aT1, const ElemType& aT2) const
+ {
+ return aT1.mStart == aT2.mStart && aT1.mEnd == aT2.mEnd;
+ }
+
+ bool LessThan(const ElemType& aT1, const ElemType& aT2) const {
+ return aT1.mStart - aT1.mFuzz < aT2.mStart + aT2.mFuzz;
+ }
+ };
+};
+
+ // clang doesn't allow for this to be defined inline of IntervalSet.
+template<typename T>
+IntervalSet<T> Union(const IntervalSet<T>& aIntervals1,
+ const IntervalSet<T>& aIntervals2)
+{
+ IntervalSet<T> intervals(aIntervals1);
+ intervals.Union(aIntervals2);
+ return intervals;
+}
+
+template<typename T>
+IntervalSet<T> Intersection(const IntervalSet<T>& aIntervals1,
+ const IntervalSet<T>& aIntervals2)
+{
+ IntervalSet<T> intersection(aIntervals1);
+ intersection.Intersection(aIntervals2);
+ return intersection;
+}
+
+} // namespace media
+} // namespace mozilla
+
+#endif // INTERVALS_H