Chromium Code Reviews
chromiumcodereview-hr@appspot.gserviceaccount.com (chromiumcodereview-hr) | Please choose your nickname with Settings | Help | Chromium Project | Gerrit Changes | Sign out
(1488)

Unified Diff: net/quic/interval_set.h

Issue 2193073003: Move shared files in net/quic/ into net/quic/core/ (Closed) Base URL: https://chromium.googlesource.com/chromium/src.git@master
Patch Set: io_thread_unittest.cc Created 4 years, 5 months ago
Use n/p to move between diff chunks; N/P to move between comments. Draft comments are only viewable by you.
Jump to:
View side-by-side diff with in-line comments
Download patch
« no previous file with comments | « net/quic/interval.h ('k') | net/quic/interval_set_test.cc » ('j') | no next file with comments »
Expand Comments ('e') | Collapse Comments ('c') | Show Comments Hide Comments ('s')
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_
« no previous file with comments | « net/quic/interval.h ('k') | net/quic/interval_set_test.cc » ('j') | no next file with comments »

Powered by Google App Engine
This is Rietveld 408576698