1 files changed, 152 insertions, 0 deletions
diff --git a/gfx/2d/BaseMargin.h b/gfx/2d/BaseMargin.h
new file mode 100644
index 000000000..76f0a5296
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+++ b/gfx/2d/BaseMargin.h
@@ -0,0 +1,152 @@
+/* -*- 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 MOZILLA_GFX_BASEMARGIN_H_
+#define MOZILLA_GFX_BASEMARGIN_H_
+
+#include <ostream>
+
+#include "Types.h"
+
+namespace mozilla {
+
+/**
+ * Sides represents a set of physical sides.
+ */
+struct Sides final {
+  Sides() : mBits(0) {}
+  explicit Sides(SideBits aSideBits)
+  {
+    MOZ_ASSERT((aSideBits & ~eSideBitsAll) == 0, "illegal side bits");
+    mBits = aSideBits;
+  }
+  bool IsEmpty() const { return mBits == 0; }
+  bool Top()     const { return (mBits & eSideBitsTop) != 0; }
+  bool Right()   const { return (mBits & eSideBitsRight) != 0; }
+  bool Bottom()  const { return (mBits & eSideBitsBottom) != 0; }
+  bool Left()    const { return (mBits & eSideBitsLeft) != 0; }
+  bool Contains(SideBits aSideBits) const
+  {
+    MOZ_ASSERT((aSideBits & ~eSideBitsAll) == 0, "illegal side bits");
+    return (mBits & aSideBits) == aSideBits;
+  }
+  Sides operator|(Sides aOther) const
+  {
+    return Sides(SideBits(mBits | aOther.mBits));
+  }
+  Sides operator|(SideBits aSideBits) const
+  {
+    return *this | Sides(aSideBits);
+  }
+  Sides& operator|=(Sides aOther)
+  {
+    mBits |= aOther.mBits;
+    return *this;
+  }
+  Sides& operator|=(SideBits aSideBits)
+  {
+    return *this |= Sides(aSideBits);
+  }
+  bool operator==(Sides aOther) const
+  {
+    return mBits == aOther.mBits;
+  }
+  bool operator!=(Sides aOther) const
+  {
+    return !(*this == aOther);
+  }
+
+private:
+  uint8_t mBits;
+};
+
+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::Side SideT; // because we have a method named Side
+
+  // 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 aTop, T aRight, T aBottom, T aLeft) :
+      top(aTop), right(aRight), bottom(aBottom), left(aLeft) {}
+
+  void SizeTo(T aTop, T aRight, T aBottom, T aLeft)
+  {
+    top = aTop; right = aRight; bottom = aBottom; left = aLeft;
+  }
+
+  T LeftRight() const { return left + right; }
+  T TopBottom() const { return top + bottom; }
+
+  T& Side(SideT aSide) {
+    // This is ugly!
+    return *(&top + int(aSide));
+  }
+  T Side(SideT aSide) const {
+    // This is ugly!
+    return *(&top + int(aSide));
+  }
+
+  void ApplySkipSides(Sides aSkipSides)
+  {
+    if (aSkipSides.Top()) {
+      top = 0;
+    }
+    if (aSkipSides.Right()) {
+      right = 0;
+    }
+    if (aSkipSides.Bottom()) {
+      bottom = 0;
+    }
+    if (aSkipSides.Left()) {
+      left = 0;
+    }
+  }
+
+  // Overloaded operators. Note that '=' isn't defined so we'll get the
+  // compiler generated default assignment operator
+  bool operator==(const Sub& aMargin) const {
+    return top == aMargin.top && right == aMargin.right &&
+           bottom == aMargin.bottom && left == aMargin.left;
+  }
+  bool operator!=(const Sub& aMargin) const {
+    return !(*this == aMargin);
+  }
+  Sub operator+(const Sub& aMargin) const {
+    return Sub(top + aMargin.top, right + aMargin.right,
+               bottom + aMargin.bottom, left + aMargin.left);
+  }
+  Sub operator-(const Sub& aMargin) const {
+    return Sub(top - aMargin.top, right - aMargin.right,
+               bottom - aMargin.bottom, left - aMargin.left);
+  }
+  Sub& operator+=(const Sub& aMargin) {
+    top += aMargin.top;
+    right += aMargin.right;
+    bottom += aMargin.bottom;
+    left += aMargin.left;
+    return *static_cast<Sub*>(this);
+  }
+
+  friend std::ostream& operator<<(std::ostream& aStream,
+      const BaseMargin& aMargin) {
+    return aStream << '(' << aMargin.top << ',' << aMargin.right << ','
+                  << aMargin.bottom << ',' << aMargin.left << ')';
+  }
+};
+
+} // namespace gfx
+} // namespace mozilla
+
+#endif /* MOZILLA_GFX_BASEMARGIN_H_ */