layout/generic/nsIntervalSet.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 // vim:cindent:ts=8:et:sw=4:
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 /* a set of ranges on a number-line */
   8
   9 #ifndef nsIntervalSet_h___
  10 #define nsIntervalSet_h___
  11
  12 #include "nsCoord.h"
  13
  14 typedef void *
  15 (* IntervalSetAlloc)(size_t aBytes, void *aClosure);
  16
  17 typedef void
  18 (* IntervalSetFree) (size_t aBytes, void *aPtr, void *aClosure);
  19
  20 /*
  21  * A list-based class (hopefully tree-based when I get around to it)
  22  * for representing a set of ranges on a number-line.
  23  */
  24 class nsIntervalSet {
  25
  26 public:
  27
  28     typedef nscoord coord_type;
  29
  30     nsIntervalSet(IntervalSetAlloc aAlloc, IntervalSetFree aFree,
  31                   void* aAllocatorClosure);
  32     ~nsIntervalSet();
  33
  34     /*
  35      * Include the interval [aBegin, aEnd] in the set.
  36      *
  37      * Removal of intervals added is not supported because that would
  38      * require keeping track of the individual intervals that were
  39      * added (nsIntervalMap should do that).  It would be simple to
  40      * implement ExcludeInterval if anyone wants it, though.
  41      */
  42     void IncludeInterval(coord_type aBegin, coord_type aEnd);
  43
  44     /*
  45      * Are _some_ points in [aBegin, aEnd] contained within the set
  46      * of intervals?
  47      */
  48     bool Intersects(coord_type aBegin, coord_type aEnd) const;
  49
  50     /*
  51      * Are _all_ points in [aBegin, aEnd] contained within the set
  52      * of intervals?
  53      */
  54     bool Contains(coord_type aBegin, coord_type aEnd) const;
  55
  56     bool IsEmpty() const
  57     {
  58         return !mList;
  59     }
  60
  61 private:
  62
  63     class Interval {
  64
  65     public:
  66         Interval(coord_type aBegin, coord_type aEnd)
  67             : mBegin(aBegin),
  68               mEnd(aEnd),
  69               mPrev(nullptr),
  70               mNext(nullptr)
  71         {
  72         }
  73
  74         coord_type mBegin;
  75         coord_type mEnd;
  76         Interval *mPrev;
  77         Interval *mNext;
  78     };
  79
  80     void FreeInterval(Interval *aInterval);
  81
  82     Interval           *mList;
  83     IntervalSetAlloc    mAlloc;
  84     IntervalSetFree     mFree;
  85     void               *mAllocatorClosure;
  86
  87 };
  88
  89 #endif // !defined(nsIntervalSet_h___)