michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef MOZILLA_GFX_BASEMARGIN_H_
michael@0: #define MOZILLA_GFX_BASEMARGIN_H_
michael@0: 
michael@0: #include "Types.h"
michael@0: 
michael@0: namespace mozilla {
michael@0: namespace gfx {
michael@0: 
michael@0: /**
michael@0:  * Do not use this class directly. Subclass it, pass that subclass as the
michael@0:  * Sub parameter, and only use that subclass.
michael@0:  */
michael@0: template <class T, class Sub>
michael@0: struct BaseMargin {
michael@0:   typedef mozilla::css::Side SideT;
michael@0: 
michael@0:   // Do not change the layout of these members; the Side() methods below
michael@0:   // depend on this order.
michael@0:   T top, right, bottom, left;
michael@0: 
michael@0:   // Constructors
michael@0:   BaseMargin() : top(0), right(0), bottom(0), left(0) {}
michael@0:   BaseMargin(T aTop, T aRight, T aBottom, T aLeft) :
michael@0:       top(aTop), right(aRight), bottom(aBottom), left(aLeft) {}
michael@0: 
michael@0:   void SizeTo(T aTop, T aRight, T aBottom, T aLeft)
michael@0:   {
michael@0:     top = aTop; right = aRight; bottom = aBottom; left = aLeft;
michael@0:   }
michael@0: 
michael@0:   T LeftRight() const { return left + right; }
michael@0:   T TopBottom() const { return top + bottom; }
michael@0: 
michael@0:   T& Side(SideT aSide) {
michael@0:     // This is ugly!
michael@0:     return *(&top + T(aSide));
michael@0:   }
michael@0:   T Side(SideT aSide) const {
michael@0:     // This is ugly!
michael@0:     return *(&top + T(aSide));
michael@0:   }
michael@0: 
michael@0:   // Overloaded operators. Note that '=' isn't defined so we'll get the
michael@0:   // compiler generated default assignment operator
michael@0:   bool operator==(const Sub& aMargin) const {
michael@0:     return top == aMargin.top && right == aMargin.right &&
michael@0:            bottom == aMargin.bottom && left == aMargin.left;
michael@0:   }
michael@0:   bool operator!=(const Sub& aMargin) const {
michael@0:     return !(*this == aMargin);
michael@0:   }
michael@0:   Sub operator+(const Sub& aMargin) const {
michael@0:     return Sub(top + aMargin.top, right + aMargin.right,
michael@0:                bottom + aMargin.bottom, left + aMargin.left);
michael@0:   }
michael@0:   Sub operator-(const Sub& aMargin) const {
michael@0:     return Sub(top - aMargin.top, right - aMargin.right,
michael@0:                bottom - aMargin.bottom, left - aMargin.left);
michael@0:   }
michael@0:   Sub& operator+=(const Sub& aMargin) {
michael@0:     top += aMargin.top;
michael@0:     right += aMargin.right;
michael@0:     bottom += aMargin.bottom;
michael@0:     left += aMargin.left;
michael@0:     return *static_cast<Sub*>(this);
michael@0:   }
michael@0: };
michael@0: 
michael@0: }
michael@0: }
michael@0: 
michael@0: #endif /* MOZILLA_GFX_BASEMARGIN_H_ */