| Index: net/quic/interval_set.h
|
| diff --git a/net/quic/interval_set.h b/net/quic/interval_set.h
|
| deleted file mode 100644
|
| index e7e4b6d2f74942034eebfd4cc08e25874f00e5c3..0000000000000000000000000000000000000000
|
| --- a/net/quic/interval_set.h
|
| +++ /dev/null
|
| @@ -1,857 +0,0 @@
|
| -// Copyright 2015 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.
|
| -//
|
| -// IntervalSet<T> is a data structure used to represent a sorted set of
|
| -// non-empty, non-adjacent, and mutually disjoint intervals. Mutations to an
|
| -// interval set preserve these properties, altering the set as needed. For
|
| -// example, adding [2, 3) to a set containing only [1, 2) would result in the
|
| -// set containing the single interval [1, 3).
|
| -//
|
| -// Supported operations include testing whether an Interval is contained in the
|
| -// IntervalSet, comparing two IntervalSets, and performing IntervalSet union,
|
| -// intersection, and difference.
|
| -//
|
| -// IntervalSet maintains the minimum number of entries needed to represent the
|
| -// set of underlying intervals. When the IntervalSet is modified (e.g. due to an
|
| -// Add operation), other interval entries may be coalesced, removed, or
|
| -// otherwise modified in order to maintain this invariant. The intervals are
|
| -// maintained in sorted order, by ascending min() value.
|
| -//
|
| -// The reader is cautioned to beware of the terminology used here: this library
|
| -// uses the terms "min" and "max" rather than "begin" and "end" as is
|
| -// conventional for the STL. The terminology [min, max) refers to the half-open
|
| -// interval which (if the interval is not empty) contains min but does not
|
| -// contain max. An interval is considered empty if min >= max.
|
| -//
|
| -// T is required to be default- and copy-constructible, to have an assignment
|
| -// operator, a difference operator (operator-()), and the full complement of
|
| -// comparison operators (<, <=, ==, !=, >=, >). These requirements are inherited
|
| -// from Interval<T>.
|
| -//
|
| -// IntervalSet has constant-time move operations.
|
| -//
|
| -// This class is thread-compatible if T is thread-compatible. (See
|
| -// go/thread-compatible).
|
| -//
|
| -// Examples:
|
| -// IntervalSet<int> intervals;
|
| -// intervals.Add(Interval<int>(10, 20));
|
| -// intervals.Add(Interval<int>(30, 40));
|
| -// // intervals contains [10,20) and [30,40).
|
| -// intervals.Add(Interval<int>(15, 35));
|
| -// // intervals has been coalesced. It now contains the single range [10,40).
|
| -// EXPECT_EQ(1, intervals.Size());
|
| -// EXPECT_TRUE(intervals.Contains(Interval<int>(10, 40)));
|
| -//
|
| -// intervals.Difference(Interval<int>(10, 20));
|
| -// // intervals should now contain the single range [20, 40).
|
| -// EXPECT_EQ(1, intervals.Size());
|
| -// EXPECT_TRUE(intervals.Contains(Interval<int>(20, 40)));
|
| -
|
| -#ifndef NET_QUIC_INTERVAL_SET_H_
|
| -#define NET_QUIC_INTERVAL_SET_H_
|
| -
|
| -#include <stddef.h>
|
| -
|
| -#include <algorithm>
|
| -#include <set>
|
| -#include <string>
|
| -#include <utility>
|
| -#include <vector>
|
| -
|
| -#include "base/logging.h"
|
| -#include "net/quic/interval.h"
|
| -
|
| -namespace net {
|
| -
|
| -template <typename T>
|
| -class IntervalSet {
|
| - private:
|
| - struct IntervalComparator {
|
| - bool operator()(const Interval<T>& a, const Interval<T>& b) const;
|
| - };
|
| - typedef std::set<Interval<T>, IntervalComparator> Set;
|
| -
|
| - public:
|
| - typedef typename Set::value_type value_type;
|
| - typedef typename Set::const_iterator const_iterator;
|
| - typedef typename Set::const_reverse_iterator const_reverse_iterator;
|
| -
|
| - // Instantiates an empty IntervalSet.
|
| - IntervalSet() {}
|
| -
|
| - // Instantiates an IntervalSet containing exactly one initial half-open
|
| - // interval [min, max), unless the given interval is empty, in which case the
|
| - // IntervalSet will be empty.
|
| - explicit IntervalSet(const Interval<T>& interval) { Add(interval); }
|
| -
|
| - // Instantiates an IntervalSet containing the half-open interval [min, max).
|
| - IntervalSet(const T& min, const T& max) { Add(min, max); }
|
| -
|
| -// TODO(rtenneti): Implement after suupport for std::initializer_list.
|
| -#if 0
|
| - IntervalSet(std::initializer_list<value_type> il) { assign(il); }
|
| -#endif
|
| -
|
| - // Clears this IntervalSet.
|
| - void Clear() { intervals_.clear(); }
|
| -
|
| - // Returns the number of disjoint intervals contained in this IntervalSet.
|
| - size_t Size() const { return intervals_.size(); }
|
| -
|
| - // Returns the smallest interval that contains all intervals in this
|
| - // IntervalSet, or the empty interval if the set is empty.
|
| - Interval<T> SpanningInterval() const;
|
| -
|
| - // Adds "interval" to this IntervalSet. Adding the empty interval has no
|
| - // effect.
|
| - void Add(const Interval<T>& interval);
|
| -
|
| - // Adds the interval [min, max) to this IntervalSet. Adding the empty interval
|
| - // has no effect.
|
| - void Add(const T& min, const T& max) { Add(Interval<T>(min, max)); }
|
| -
|
| - // DEPRECATED(kosak). Use Union() instead. This method merges all of the
|
| - // values contained in "other" into this IntervalSet.
|
| - void Add(const IntervalSet& other);
|
| -
|
| - // Returns true if this IntervalSet represents exactly the same set of
|
| - // intervals as the ones represented by "other".
|
| - bool Equals(const IntervalSet& other) const;
|
| -
|
| - // Returns true if this IntervalSet is empty.
|
| - bool Empty() const { return intervals_.empty(); }
|
| -
|
| - // Returns true if any interval in this IntervalSet contains the indicated
|
| - // value.
|
| - bool Contains(const T& value) const;
|
| -
|
| - // Returns true if there is some interval in this IntervalSet that wholly
|
| - // contains the given interval. An interval O "wholly contains" a non-empty
|
| - // interval I if O.Contains(p) is true for every p in I. This is the same
|
| - // definition used by Interval<T>::Contains(). This method returns false on
|
| - // the empty interval, due to a (perhaps unintuitive) convention inherited
|
| - // from Interval<T>.
|
| - // Example:
|
| - // Assume an IntervalSet containing the entries { [10,20), [30,40) }.
|
| - // Contains(Interval(15, 16)) returns true, because [10,20) contains
|
| - // [15,16). However, Contains(Interval(15, 35)) returns false.
|
| - bool Contains(const Interval<T>& interval) const;
|
| -
|
| - // Returns true if for each interval in "other", there is some (possibly
|
| - // different) interval in this IntervalSet which wholly contains it. See
|
| - // Contains(const Interval<T>& interval) for the meaning of "wholly contains".
|
| - // Perhaps unintuitively, this method returns false if "other" is the empty
|
| - // set. The algorithmic complexity of this method is O(other.Size() *
|
| - // log(this->Size())), which is not efficient. The method could be rewritten
|
| - // to run in O(other.Size() + this->Size()).
|
| - bool Contains(const IntervalSet<T>& other) const;
|
| -
|
| - // Returns true if there is some interval in this IntervalSet that wholly
|
| - // contains the interval [min, max). See Contains(const Interval<T>&).
|
| - bool Contains(const T& min, const T& max) const {
|
| - return Contains(Interval<T>(min, max));
|
| - }
|
| -
|
| - // Returns true if for some interval in "other", there is some interval in
|
| - // this IntervalSet that intersects with it. See Interval<T>::Intersects()
|
| - // for the definition of interval intersection.
|
| - bool Intersects(const IntervalSet& other) const;
|
| -
|
| - // Returns an iterator to the Interval<T> in the IntervalSet that contains the
|
| - // given value. In other words, returns an iterator to the unique interval
|
| - // [min, max) in the IntervalSet that has the property min <= value < max. If
|
| - // there is no such interval, this method returns end().
|
| - const_iterator Find(const T& value) const;
|
| -
|
| - // Returns an iterator to the Interval<T> in the IntervalSet that wholly
|
| - // contains the given interval. In other words, returns an iterator to the
|
| - // unique interval outer in the IntervalSet that has the property that
|
| - // outer.Contains(interval). If there is no such interval, or if interval is
|
| - // empty, returns end().
|
| - const_iterator Find(const Interval<T>& interval) const;
|
| -
|
| - // Returns an iterator to the Interval<T> in the IntervalSet that wholly
|
| - // contains [min, max). In other words, returns an iterator to the unique
|
| - // interval outer in the IntervalSet that has the property that
|
| - // outer.Contains(Interval<T>(min, max)). If there is no such interval, or if
|
| - // interval is empty, returns end().
|
| - const_iterator Find(const T& min, const T& max) const {
|
| - return Find(Interval<T>(min, max));
|
| - }
|
| -
|
| - // Returns true if every value within the passed interval is not Contained
|
| - // within the IntervalSet.
|
| - bool IsDisjoint(const Interval<T>& interval) const;
|
| -
|
| - // Merges all the values contained in "other" into this IntervalSet.
|
| - void Union(const IntervalSet& other);
|
| -
|
| - // Modifies this IntervalSet so that it contains only those values that are
|
| - // currently present both in *this and in the IntervalSet "other".
|
| - void Intersection(const IntervalSet& other);
|
| -
|
| - // Mutates this IntervalSet so that it contains only those values that are
|
| - // currently in *this but not in "interval".
|
| - void Difference(const Interval<T>& interval);
|
| -
|
| - // Mutates this IntervalSet so that it contains only those values that are
|
| - // currently in *this but not in the interval [min, max).
|
| - void Difference(const T& min, const T& max);
|
| -
|
| - // Mutates this IntervalSet so that it contains only those values that are
|
| - // currently in *this but not in the IntervalSet "other".
|
| - void Difference(const IntervalSet& other);
|
| -
|
| - // Mutates this IntervalSet so that it contains only those values that are
|
| - // in [min, max) but not currently in *this.
|
| - void Complement(const T& min, const T& max);
|
| -
|
| - // IntervalSet's begin() iterator. The invariants of IntervalSet guarantee
|
| - // that for each entry e in the set, e.min() < e.max() (because the entries
|
| - // are non-empty) and for each entry f that appears later in the set,
|
| - // e.max() < f.min() (because the entries are ordered, pairwise-disjoint, and
|
| - // non-adjacent). Modifications to this IntervalSet invalidate these
|
| - // iterators.
|
| - const_iterator begin() const { return intervals_.begin(); }
|
| -
|
| - // IntervalSet's end() iterator.
|
| - const_iterator end() const { return intervals_.end(); }
|
| -
|
| - // IntervalSet's rbegin() and rend() iterators. Iterator invalidation
|
| - // semantics are the same as those for begin() / end().
|
| - const_reverse_iterator rbegin() const { return intervals_.rbegin(); }
|
| -
|
| - const_reverse_iterator rend() const { return intervals_.rend(); }
|
| -
|
| - // Appends the intervals in this IntervalSet to the end of *out.
|
| - void Get(std::vector<Interval<T>>* out) const {
|
| - out->insert(out->end(), begin(), end());
|
| - }
|
| -
|
| - // Copies the intervals in this IntervalSet to the given output iterator.
|
| - template <typename Iter>
|
| - Iter Get(Iter out_iter) const {
|
| - return std::copy(begin(), end(), out_iter);
|
| - }
|
| -
|
| - template <typename Iter>
|
| - void assign(Iter first, Iter last) {
|
| - Clear();
|
| - for (; first != last; ++first)
|
| - Add(*first);
|
| - }
|
| -
|
| -// TODO(rtenneti): Implement after suupport for std::initializer_list.
|
| -#if 0
|
| - void assign(std::initializer_list<value_type> il) {
|
| - assign(il.begin(), il.end());
|
| - }
|
| -#endif
|
| -
|
| - // Returns a human-readable representation of this set. This will typically be
|
| - // (though is not guaranteed to be) of the form
|
| - // "[a1, b1) [a2, b2) ... [an, bn)"
|
| - // where the intervals are in the same order as given by traversal from
|
| - // begin() to end(). This representation is intended for human consumption;
|
| - // computer programs should not rely on the output being in exactly this form.
|
| - std::string ToString() const;
|
| -
|
| - // Equality for IntervalSet<T>. Delegates to Equals().
|
| - bool operator==(const IntervalSet& other) const { return Equals(other); }
|
| -
|
| - // Inequality for IntervalSet<T>. Delegates to Equals() (and returns its
|
| - // negation).
|
| - bool operator!=(const IntervalSet& other) const { return !Equals(other); }
|
| -
|
| -// TODO(rtenneti): Implement after suupport for std::initializer_list.
|
| -#if 0
|
| - IntervalSet& operator=(std::initializer_list<value_type> il) {
|
| - assign(il.begin(), il.end());
|
| - return *this;
|
| - }
|
| -#endif
|
| -
|
| - // Swap this IntervalSet with *other. This is a constant-time operation.
|
| - void Swap(IntervalSet<T>* other) { intervals_.swap(other->intervals_); }
|
| -
|
| - private:
|
| - // Removes overlapping ranges and coalesces adjacent intervals as needed.
|
| - void Compact(const typename Set::iterator& begin,
|
| - const typename Set::iterator& end);
|
| -
|
| - // Returns true if this set is valid (i.e. all intervals in it are non-empty,
|
| - // non-adjacent, and mutually disjoint). Currently this is used as an
|
| - // integrity check by the Intersection() and Difference() methods, but is only
|
| - // invoked for debug builds (via DCHECK).
|
| - bool Valid() const;
|
| -
|
| - // Finds the first interval that potentially intersects 'other'.
|
| - const_iterator FindIntersectionCandidate(const IntervalSet& other) const;
|
| -
|
| - // Finds the first interval that potentially intersects 'interval'.
|
| - const_iterator FindIntersectionCandidate(const Interval<T>& interval) const;
|
| -
|
| - // Helper for Intersection() and Difference(): Finds the next pair of
|
| - // intervals from 'x' and 'y' that intersect. 'mine' is an iterator
|
| - // over x->intervals_. 'theirs' is an iterator over y.intervals_. 'mine'
|
| - // and 'theirs' are advanced until an intersecting pair is found.
|
| - // Non-intersecting intervals (aka "holes") from x->intervals_ can be
|
| - // optionally erased by "on_hole".
|
| - template <typename X, typename Func>
|
| - static bool FindNextIntersectingPairImpl(X* x,
|
| - const IntervalSet& y,
|
| - const_iterator* mine,
|
| - const_iterator* theirs,
|
| - Func on_hole);
|
| -
|
| - // The variant of the above method that doesn't mutate this IntervalSet.
|
| - bool FindNextIntersectingPair(const IntervalSet& other,
|
| - const_iterator* mine,
|
| - const_iterator* theirs) const {
|
| - return FindNextIntersectingPairImpl(
|
| - this, other, mine, theirs,
|
| - [](const IntervalSet*, const_iterator, const_iterator) {});
|
| - }
|
| -
|
| - // The variant of the above method that mutates this IntervalSet by erasing
|
| - // holes.
|
| - bool FindNextIntersectingPairAndEraseHoles(const IntervalSet& other,
|
| - const_iterator* mine,
|
| - const_iterator* theirs) {
|
| - return FindNextIntersectingPairImpl(
|
| - this, other, mine, theirs,
|
| - [](IntervalSet* x, const_iterator from, const_iterator to) {
|
| - x->intervals_.erase(from, to);
|
| - });
|
| - }
|
| -
|
| - // The representation for the intervals. The intervals in this set are
|
| - // non-empty, pairwise-disjoint, non-adjacent and ordered in ascending order
|
| - // by min().
|
| - Set intervals_;
|
| -};
|
| -
|
| -template <typename T>
|
| -std::ostream& operator<<(std::ostream& out, const IntervalSet<T>& seq);
|
| -
|
| -template <typename T>
|
| -void swap(IntervalSet<T>& x, IntervalSet<T>& y);
|
| -
|
| -//==============================================================================
|
| -// Implementation details: Clients can stop reading here.
|
| -
|
| -template <typename T>
|
| -Interval<T> IntervalSet<T>::SpanningInterval() const {
|
| - Interval<T> result;
|
| - if (!intervals_.empty()) {
|
| - result.SetMin(intervals_.begin()->min());
|
| - result.SetMax(intervals_.rbegin()->max());
|
| - }
|
| - return result;
|
| -}
|
| -
|
| -template <typename T>
|
| -void IntervalSet<T>::Add(const Interval<T>& interval) {
|
| - if (interval.Empty())
|
| - return;
|
| - std::pair<typename Set::iterator, bool> ins = intervals_.insert(interval);
|
| - if (!ins.second) {
|
| - // This interval already exists.
|
| - return;
|
| - }
|
| - // Determine the minimal range that will have to be compacted. We know that
|
| - // the IntervalSet was valid before the addition of the interval, so only
|
| - // need to start with the interval itself (although Compact takes an open
|
| - // range so begin needs to be the interval to the left). We don't know how
|
| - // many ranges this interval may cover, so we need to find the appropriate
|
| - // interval to end with on the right.
|
| - typename Set::iterator begin = ins.first;
|
| - if (begin != intervals_.begin())
|
| - --begin;
|
| - const Interval<T> target_end(interval.max(), interval.max());
|
| - const typename Set::iterator end = intervals_.upper_bound(target_end);
|
| - Compact(begin, end);
|
| -}
|
| -
|
| -template <typename T>
|
| -void IntervalSet<T>::Add(const IntervalSet& other) {
|
| - for (const_iterator it = other.begin(); it != other.end(); ++it) {
|
| - Add(*it);
|
| - }
|
| -}
|
| -
|
| -template <typename T>
|
| -bool IntervalSet<T>::Equals(const IntervalSet& other) const {
|
| - if (intervals_.size() != other.intervals_.size())
|
| - return false;
|
| - for (typename Set::iterator i = intervals_.begin(),
|
| - j = other.intervals_.begin();
|
| - i != intervals_.end(); ++i, ++j) {
|
| - // Simple member-wise equality, since all intervals are non-empty.
|
| - if (i->min() != j->min() || i->max() != j->max())
|
| - return false;
|
| - }
|
| - return true;
|
| -}
|
| -
|
| -template <typename T>
|
| -bool IntervalSet<T>::Contains(const T& value) const {
|
| - Interval<T> tmp(value, value);
|
| - // Find the first interval with min() > value, then move back one step
|
| - const_iterator it = intervals_.upper_bound(tmp);
|
| - if (it == intervals_.begin())
|
| - return false;
|
| - --it;
|
| - return it->Contains(value);
|
| -}
|
| -
|
| -template <typename T>
|
| -bool IntervalSet<T>::Contains(const Interval<T>& interval) const {
|
| - // Find the first interval with min() > value, then move back one step.
|
| - const_iterator it = intervals_.upper_bound(interval);
|
| - if (it == intervals_.begin())
|
| - return false;
|
| - --it;
|
| - return it->Contains(interval);
|
| -}
|
| -
|
| -template <typename T>
|
| -bool IntervalSet<T>::Contains(const IntervalSet<T>& other) const {
|
| - if (!SpanningInterval().Contains(other.SpanningInterval())) {
|
| - return false;
|
| - }
|
| -
|
| - for (const_iterator i = other.begin(); i != other.end(); ++i) {
|
| - // If we don't contain the interval, can return false now.
|
| - if (!Contains(*i)) {
|
| - return false;
|
| - }
|
| - }
|
| - return true;
|
| -}
|
| -
|
| -// This method finds the interval that Contains() "value", if such an interval
|
| -// exists in the IntervalSet. The way this is done is to locate the "candidate
|
| -// interval", the only interval that could *possibly* contain value, and test it
|
| -// using Contains(). The candidate interval is the interval with the largest
|
| -// min() having min() <= value.
|
| -//
|
| -// Determining the candidate interval takes a couple of steps. First, since the
|
| -// underlying std::set stores intervals, not values, we need to create a "probe
|
| -// interval" suitable for use as a search key. The probe interval used is
|
| -// [value, value). Now we can restate the problem as finding the largest
|
| -// interval in the IntervalSet that is <= the probe interval.
|
| -//
|
| -// This restatement only works if the set's comparator behaves in a certain way.
|
| -// In particular it needs to order first by ascending min(), and then by
|
| -// descending max(). The comparator used by this library is defined in exactly
|
| -// this way. To see why descending max() is required, consider the following
|
| -// example. Assume an IntervalSet containing these intervals:
|
| -//
|
| -// [0, 5) [10, 20) [50, 60)
|
| -//
|
| -// Consider searching for the value 15. The probe interval [15, 15) is created,
|
| -// and [10, 20) is identified as the largest interval in the set <= the probe
|
| -// interval. This is the correct interval needed for the Contains() test, which
|
| -// will then return true.
|
| -//
|
| -// Now consider searching for the value 30. The probe interval [30, 30) is
|
| -// created, and again [10, 20] is identified as the largest interval <= the
|
| -// probe interval. This is again the correct interval needed for the Contains()
|
| -// test, which in this case returns false.
|
| -//
|
| -// Finally, consider searching for the value 10. The probe interval [10, 10) is
|
| -// created. Here the ordering relationship between [10, 10) and [10, 20) becomes
|
| -// vitally important. If [10, 10) were to come before [10, 20), then [0, 5)
|
| -// would be the largest interval <= the probe, leading to the wrong choice of
|
| -// interval for the Contains() test. Therefore [10, 10) needs to come after
|
| -// [10, 20). The simplest way to make this work in the general case is to order
|
| -// by ascending min() but descending max(). In this ordering, the empty interval
|
| -// is larger than any non-empty interval with the same min(). The comparator
|
| -// used by this library is careful to induce this ordering.
|
| -//
|
| -// Another detail involves the choice of which std::set method to use to try to
|
| -// find the candidate interval. The most appropriate entry point is
|
| -// set::upper_bound(), which finds the smallest interval which is > the probe
|
| -// interval. The semantics of upper_bound() are slightly different from what we
|
| -// want (namely, to find the largest interval which is <= the probe interval)
|
| -// but they are close enough; the interval found by upper_bound() will always be
|
| -// one step past the interval we are looking for (if it exists) or at begin()
|
| -// (if it does not). Getting to the proper interval is a simple matter of
|
| -// decrementing the iterator.
|
| -template <typename T>
|
| -typename IntervalSet<T>::const_iterator IntervalSet<T>::Find(
|
| - const T& value) const {
|
| - Interval<T> tmp(value, value);
|
| - const_iterator it = intervals_.upper_bound(tmp);
|
| - if (it == intervals_.begin())
|
| - return intervals_.end();
|
| - --it;
|
| - if (it->Contains(value))
|
| - return it;
|
| - else
|
| - return intervals_.end();
|
| -}
|
| -
|
| -// This method finds the interval that Contains() the interval "probe", if such
|
| -// an interval exists in the IntervalSet. The way this is done is to locate the
|
| -// "candidate interval", the only interval that could *possibly* contain
|
| -// "probe", and test it using Contains(). The candidate interval is the largest
|
| -// interval that is <= the probe interval.
|
| -//
|
| -// The search for the candidate interval only works if the comparator used
|
| -// behaves in a certain way. In particular it needs to order first by ascending
|
| -// min(), and then by descending max(). The comparator used by this library is
|
| -// defined in exactly this way. To see why descending max() is required,
|
| -// consider the following example. Assume an IntervalSet containing these
|
| -// intervals:
|
| -//
|
| -// [0, 5) [10, 20) [50, 60)
|
| -//
|
| -// Consider searching for the probe [15, 17). [10, 20) is the largest interval
|
| -// in the set which is <= the probe interval. This is the correct interval
|
| -// needed for the Contains() test, which will then return true, because [10, 20)
|
| -// contains [15, 17).
|
| -//
|
| -// Now consider searching for the probe [30, 32). Again [10, 20] is the largest
|
| -// interval <= the probe interval. This is again the correct interval needed for
|
| -// the Contains() test, which in this case returns false, because [10, 20) does
|
| -// not contain [30, 32).
|
| -//
|
| -// Finally, consider searching for the probe [10, 12). Here the ordering
|
| -// relationship between [10, 12) and [10, 20) becomes vitally important. If
|
| -// [10, 12) were to come before [10, 20), then [0, 5) would be the largest
|
| -// interval <= the probe, leading to the wrong choice of interval for the
|
| -// Contains() test. Therefore [10, 12) needs to come after [10, 20). The
|
| -// simplest way to make this work in the general case is to order by ascending
|
| -// min() but descending max(). In this ordering, given two intervals with the
|
| -// same min(), the wider one goes before the narrower one. The comparator used
|
| -// by this library is careful to induce this ordering.
|
| -//
|
| -// Another detail involves the choice of which std::set method to use to try to
|
| -// find the candidate interval. The most appropriate entry point is
|
| -// set::upper_bound(), which finds the smallest interval which is > the probe
|
| -// interval. The semantics of upper_bound() are slightly different from what we
|
| -// want (namely, to find the largest interval which is <= the probe interval)
|
| -// but they are close enough; the interval found by upper_bound() will always be
|
| -// one step past the interval we are looking for (if it exists) or at begin()
|
| -// (if it does not). Getting to the proper interval is a simple matter of
|
| -// decrementing the iterator.
|
| -template <typename T>
|
| -typename IntervalSet<T>::const_iterator IntervalSet<T>::Find(
|
| - const Interval<T>& probe) const {
|
| - const_iterator it = intervals_.upper_bound(probe);
|
| - if (it == intervals_.begin())
|
| - return intervals_.end();
|
| - --it;
|
| - if (it->Contains(probe))
|
| - return it;
|
| - else
|
| - return intervals_.end();
|
| -}
|
| -
|
| -template <typename T>
|
| -bool IntervalSet<T>::IsDisjoint(const Interval<T>& interval) const {
|
| - Interval<T> tmp(interval.min(), interval.min());
|
| - // Find the first interval with min() > interval.min()
|
| - const_iterator it = intervals_.upper_bound(tmp);
|
| - if (it != intervals_.end() && interval.max() > it->min())
|
| - return false;
|
| - if (it == intervals_.begin())
|
| - return true;
|
| - --it;
|
| - return it->max() <= interval.min();
|
| -}
|
| -
|
| -template <typename T>
|
| -void IntervalSet<T>::Union(const IntervalSet& other) {
|
| - intervals_.insert(other.begin(), other.end());
|
| - Compact(intervals_.begin(), intervals_.end());
|
| -}
|
| -
|
| -template <typename T>
|
| -typename IntervalSet<T>::const_iterator
|
| -IntervalSet<T>::FindIntersectionCandidate(const IntervalSet& other) const {
|
| - return FindIntersectionCandidate(*other.intervals_.begin());
|
| -}
|
| -
|
| -template <typename T>
|
| -typename IntervalSet<T>::const_iterator
|
| -IntervalSet<T>::FindIntersectionCandidate(const Interval<T>& interval) const {
|
| - // Use upper_bound to efficiently find the first interval in intervals_
|
| - // where min() is greater than interval.min(). If the result
|
| - // isn't the beginning of intervals_ then move backwards one interval since
|
| - // the interval before it is the first candidate where max() may be
|
| - // greater than interval.min().
|
| - // In other words, no interval before that can possibly intersect with any
|
| - // of other.intervals_.
|
| - const_iterator mine = intervals_.upper_bound(interval);
|
| - if (mine != intervals_.begin()) {
|
| - --mine;
|
| - }
|
| - return mine;
|
| -}
|
| -
|
| -template <typename T>
|
| -template <typename X, typename Func>
|
| -bool IntervalSet<T>::FindNextIntersectingPairImpl(X* x,
|
| - const IntervalSet& y,
|
| - const_iterator* mine,
|
| - const_iterator* theirs,
|
| - Func on_hole) {
|
| - CHECK(x != nullptr);
|
| - if ((*mine == x->intervals_.end()) || (*theirs == y.intervals_.end())) {
|
| - return false;
|
| - }
|
| - while (!(**mine).Intersects(**theirs)) {
|
| - const_iterator erase_first = *mine;
|
| - // Skip over intervals in 'mine' that don't reach 'theirs'.
|
| - while (*mine != x->intervals_.end() && (**mine).max() <= (**theirs).min()) {
|
| - ++(*mine);
|
| - }
|
| - on_hole(x, erase_first, *mine);
|
| - // We're done if the end of intervals_ is reached.
|
| - if (*mine == x->intervals_.end()) {
|
| - return false;
|
| - }
|
| - // Skip over intervals 'theirs' that don't reach 'mine'.
|
| - while (*theirs != y.intervals_.end() &&
|
| - (**theirs).max() <= (**mine).min()) {
|
| - ++(*theirs);
|
| - }
|
| - // If the end of other.intervals_ is reached, we're done.
|
| - if (*theirs == y.intervals_.end()) {
|
| - on_hole(x, *mine, x->intervals_.end());
|
| - return false;
|
| - }
|
| - }
|
| - return true;
|
| -}
|
| -
|
| -template <typename T>
|
| -void IntervalSet<T>::Intersection(const IntervalSet& other) {
|
| - if (!SpanningInterval().Intersects(other.SpanningInterval())) {
|
| - intervals_.clear();
|
| - return;
|
| - }
|
| -
|
| - const_iterator mine = FindIntersectionCandidate(other);
|
| - // Remove any intervals that cannot possibly intersect with other.intervals_.
|
| - intervals_.erase(intervals_.begin(), mine);
|
| - const_iterator theirs = other.FindIntersectionCandidate(*this);
|
| -
|
| - while (FindNextIntersectingPairAndEraseHoles(other, &mine, &theirs)) {
|
| - // OK, *mine and *theirs intersect. Now, we find the largest
|
| - // span of intervals in other (starting at theirs) - say [a..b]
|
| - // - that intersect *mine, and we replace *mine with (*mine
|
| - // intersect x) for all x in [a..b] Note that subsequent
|
| - // intervals in this can't intersect any intervals in [a..b) --
|
| - // they may only intersect b or subsequent intervals in other.
|
| - Interval<T> i(*mine);
|
| - intervals_.erase(mine);
|
| - mine = intervals_.end();
|
| - Interval<T> intersection;
|
| - while (theirs != other.intervals_.end() &&
|
| - i.Intersects(*theirs, &intersection)) {
|
| - std::pair<typename Set::iterator, bool> ins =
|
| - intervals_.insert(intersection);
|
| - DCHECK(ins.second);
|
| - mine = ins.first;
|
| - ++theirs;
|
| - }
|
| - DCHECK(mine != intervals_.end());
|
| - --theirs;
|
| - ++mine;
|
| - }
|
| - DCHECK(Valid());
|
| -}
|
| -
|
| -template <typename T>
|
| -bool IntervalSet<T>::Intersects(const IntervalSet& other) const {
|
| - if (!SpanningInterval().Intersects(other.SpanningInterval())) {
|
| - return false;
|
| - }
|
| -
|
| - const_iterator mine = FindIntersectionCandidate(other);
|
| - if (mine == intervals_.end()) {
|
| - return false;
|
| - }
|
| - const_iterator theirs = other.FindIntersectionCandidate(*mine);
|
| -
|
| - return FindNextIntersectingPair(other, &mine, &theirs);
|
| -}
|
| -
|
| -template <typename T>
|
| -void IntervalSet<T>::Difference(const Interval<T>& interval) {
|
| - if (!SpanningInterval().Intersects(interval)) {
|
| - return;
|
| - }
|
| - Difference(IntervalSet<T>(interval));
|
| -}
|
| -
|
| -template <typename T>
|
| -void IntervalSet<T>::Difference(const T& min, const T& max) {
|
| - Difference(Interval<T>(min, max));
|
| -}
|
| -
|
| -template <typename T>
|
| -void IntervalSet<T>::Difference(const IntervalSet& other) {
|
| - if (!SpanningInterval().Intersects(other.SpanningInterval())) {
|
| - return;
|
| - }
|
| -
|
| - const_iterator mine = FindIntersectionCandidate(other);
|
| - // If no interval in mine reaches the first interval of theirs then we're
|
| - // done.
|
| - if (mine == intervals_.end()) {
|
| - return;
|
| - }
|
| - const_iterator theirs = other.FindIntersectionCandidate(*this);
|
| -
|
| - while (FindNextIntersectingPair(other, &mine, &theirs)) {
|
| - // At this point *mine and *theirs overlap. Remove mine from
|
| - // intervals_ and replace it with the possibly two intervals that are
|
| - // the difference between mine and theirs.
|
| - Interval<T> i(*mine);
|
| - intervals_.erase(mine++);
|
| - Interval<T> lo;
|
| - Interval<T> hi;
|
| - i.Difference(*theirs, &lo, &hi);
|
| -
|
| - if (!lo.Empty()) {
|
| - // We have a low end. This can't intersect anything else.
|
| - std::pair<typename Set::iterator, bool> ins = intervals_.insert(lo);
|
| - DCHECK(ins.second);
|
| - }
|
| -
|
| - if (!hi.Empty()) {
|
| - std::pair<typename Set::iterator, bool> ins = intervals_.insert(hi);
|
| - DCHECK(ins.second);
|
| - mine = ins.first;
|
| - }
|
| - }
|
| - DCHECK(Valid());
|
| -}
|
| -
|
| -template <typename T>
|
| -void IntervalSet<T>::Complement(const T& min, const T& max) {
|
| - IntervalSet<T> span(min, max);
|
| - span.Difference(*this);
|
| - intervals_.swap(span.intervals_);
|
| -}
|
| -
|
| -template <typename T>
|
| -std::string IntervalSet<T>::ToString() const {
|
| - std::ostringstream os;
|
| - os << *this;
|
| - return os.str();
|
| -}
|
| -
|
| -// This method compacts the IntervalSet, merging pairs of overlapping intervals
|
| -// into a single interval. In the steady state, the IntervalSet does not contain
|
| -// any such pairs. However, the way the Union() and Add() methods work is to
|
| -// temporarily put the IntervalSet into such a state and then to call Compact()
|
| -// to "fix it up" so that it is no longer in that state.
|
| -//
|
| -// Compact() needs the interval set to allow two intervals [a,b) and [a,c)
|
| -// (having the same min() but different max()) to briefly coexist in the set at
|
| -// the same time, and be adjacent to each other, so that they can be efficiently
|
| -// located and merged into a single interval. This state would be impossible
|
| -// with a comparator which only looked at min(), as such a comparator would
|
| -// consider such pairs equal. Fortunately, the comparator used by IntervalSet
|
| -// does exactly what is needed, ordering first by ascending min(), then by
|
| -// descending max().
|
| -template <typename T>
|
| -void IntervalSet<T>::Compact(const typename Set::iterator& begin,
|
| - const typename Set::iterator& end) {
|
| - if (begin == end)
|
| - return;
|
| - typename Set::iterator next = begin;
|
| - typename Set::iterator prev = begin;
|
| - typename Set::iterator it = begin;
|
| - ++it;
|
| - ++next;
|
| - while (it != end) {
|
| - ++next;
|
| - if (prev->max() >= it->min()) {
|
| - // Overlapping / coalesced range; merge the two intervals.
|
| - T min = prev->min();
|
| - T max = std::max(prev->max(), it->max());
|
| - Interval<T> i(min, max);
|
| - intervals_.erase(prev);
|
| - intervals_.erase(it);
|
| - std::pair<typename Set::iterator, bool> ins = intervals_.insert(i);
|
| - DCHECK(ins.second);
|
| - prev = ins.first;
|
| - } else {
|
| - prev = it;
|
| - }
|
| - it = next;
|
| - }
|
| -}
|
| -
|
| -template <typename T>
|
| -bool IntervalSet<T>::Valid() const {
|
| - const_iterator prev = end();
|
| - for (const_iterator it = begin(); it != end(); ++it) {
|
| - // invalid or empty interval.
|
| - if (it->min() >= it->max())
|
| - return false;
|
| - // Not sorted, not disjoint, or adjacent.
|
| - if (prev != end() && prev->max() >= it->min())
|
| - return false;
|
| - prev = it;
|
| - }
|
| - return true;
|
| -}
|
| -
|
| -template <typename T>
|
| -inline std::ostream& operator<<(std::ostream& out, const IntervalSet<T>& seq) {
|
| -// TODO(rtenneti): Implement << method of IntervalSet.
|
| -#if 0
|
| - util::gtl::LogRangeToStream(out, seq.begin(), seq.end(),
|
| - util::gtl::LogLegacy());
|
| -#endif // 0
|
| - return out;
|
| -}
|
| -
|
| -template <typename T>
|
| -void swap(IntervalSet<T>& x, IntervalSet<T>& y) {
|
| - x.Swap(&y);
|
| -}
|
| -
|
| -// This comparator orders intervals first by ascending min() and then by
|
| -// descending max(). Readers who are satisified with that explanation can stop
|
| -// reading here. The remainder of this comment is for the benefit of future
|
| -// maintainers of this library.
|
| -//
|
| -// The reason for this ordering is that this comparator has to serve two
|
| -// masters. First, it has to maintain the intervals in its internal set in the
|
| -// order that clients expect to see them. Clients see these intervals via the
|
| -// iterators provided by begin()/end() or as a result of invoking Get(). For
|
| -// this reason, the comparator orders intervals by ascending min().
|
| -//
|
| -// If client iteration were the only consideration, then ordering by ascending
|
| -// min() would be good enough. This is because the intervals in the IntervalSet
|
| -// are non-empty, non-adjacent, and mutually disjoint; such intervals happen to
|
| -// always have disjoint min() values, so such a comparator would never even have
|
| -// to look at max() in order to work correctly for this class.
|
| -//
|
| -// However, in addition to ordering by ascending min(), this comparator also has
|
| -// a second responsibility: satisfying the special needs of this library's
|
| -// peculiar internal implementation. These needs require the comparator to order
|
| -// first by ascending min() and then by descending max(). The best way to
|
| -// understand why this is so is to check out the comments associated with the
|
| -// Find() and Compact() methods.
|
| -template <typename T>
|
| -inline bool IntervalSet<T>::IntervalComparator::operator()(
|
| - const Interval<T>& a,
|
| - const Interval<T>& b) const {
|
| - return (a.min() < b.min() || (a.min() == b.min() && a.max() > b.max()));
|
| -}
|
| -
|
| -} // namespace net
|
| -
|
| -#endif // NET_QUIC_INTERVAL_SET_H_
|
|
|