/usr/include/thunderbird/PingPongRegion.h is in thunderbird-dev 1:52.8.0-1~deb8u1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 | /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 PingPongRegion_h__
#define PingPongRegion_h__
/* This class uses a pair of regions and swaps between them while
* accumulating to avoid the heap allocations associated with
* modifying a region in place.
*
* It is sizeof(T)*2 + sizeof(T*) and can use end up using
* approximately double the amount of memory as using single
* region so use it sparingly.
*/
template <typename T>
class PingPongRegion
{
typedef typename T::RectType RectType;
public:
PingPongRegion()
{
rgn = &rgn1;
}
void SubOut(const RectType& aOther)
{
T* nextRgn = nextRegion();
nextRgn->Sub(*rgn, aOther);
rgn = nextRgn;
}
void OrWith(const RectType& aOther)
{
T* nextRgn = nextRegion();
nextRgn->Or(*rgn, aOther);
rgn = nextRgn;
}
T& Region()
{
return *rgn;
}
private:
T* nextRegion()
{
if (rgn == &rgn1) {
return &rgn2;
} else {
return &rgn1;
}
}
T* rgn;
T rgn1;
T rgn2;
};
#endif
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