gecko/gfx/2d/BaseMargin.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Mozilla Corporation code.
*
* The Initial Developer of the Original Code is Mozilla Foundation.
* Portions created by the Initial Developer are Copyright (C) 2011
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Robert O'Callahan <robert@ocallahan.org>
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#ifndef MOZILLA_GFX_BASEMARGIN_H_
#define MOZILLA_GFX_BASEMARGIN_H_
#include "Types.h"
namespace mozilla {
namespace gfx {
/**
* Do not use this class directly. Subclass it, pass that subclass as the
* Sub parameter, and only use that subclass.
*/
template <class T, class Sub>
struct BaseMargin {
typedef mozilla::css::Side SideT;
// Do not change the layout of these members; the Side() methods below
// depend on this order.
T top, right, bottom, left;
// Constructors
BaseMargin() : top(0), right(0), bottom(0), left(0) {}
BaseMargin(T aLeft, T aTop, T aRight, T aBottom) :
top(aTop), right(aRight), bottom(aBottom), left(aLeft) {}
void SizeTo(T aLeft, T aTop, T aRight, T aBottom)
{
left = aLeft; top = aTop; right = aRight; bottom = aBottom;
}
T LeftRight() const { return left + right; }
T TopBottom() const { return top + bottom; }
T& Side(SideT aSide) {
// This is ugly!
return *(&top + aSide);
}
T Side(SideT aSide) const {
// This is ugly!
return *(&top + aSide);
}
// Overloaded operators. Note that '=' isn't defined so we'll get the
// compiler generated default assignment operator
bool operator==(const Sub& aMargin) const {
return left == aMargin.left && top == aMargin.top &&
right == aMargin.right && bottom == aMargin.bottom;
}
bool operator!=(const Sub& aMargin) const {
return !(*this == aMargin);
}
Sub operator+(const Sub& aMargin) const {
return Sub(left + aMargin.left, top + aMargin.top,
right + aMargin.right, bottom + aMargin.bottom);
}
Sub operator-(const Sub& aMargin) const {
return Sub(left - aMargin.left, top - aMargin.top,
right - aMargin.right, bottom - aMargin.bottom);
}
Sub& operator+=(const Sub& aMargin) {
left += aMargin.left;
top += aMargin.top;
right += aMargin.right;
bottom += aMargin.bottom;
return *static_cast<Sub*>(this);
}
};
}
}
#endif /* MOZILLA_GFX_BASEMARGIN_H_ */