1 files changed, 156 insertions, 0 deletions
diff --git a/gfx/2d/BaseMargin.h b/gfx/2d/BaseMargin.h
new file mode 100644
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+++ b/gfx/2d/BaseMargin.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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(SideBits::eNone) {}
+  explicit Sides(SideBits aSideBits) {
+    MOZ_ASSERT((aSideBits & ~SideBits::eAll) == SideBits::eNone,
+               "illegal side bits");
+    mBits = aSideBits;
+  }
+  bool IsEmpty() const { return mBits == SideBits::eNone; }
+  bool Top() const { return (mBits & SideBits::eTop) == SideBits::eTop; }
+  bool Right() const { return (mBits & SideBits::eRight) == SideBits::eRight; }
+  bool Bottom() const {
+    return (mBits & SideBits::eBottom) == SideBits::eBottom;
+  }
+  bool Left() const { return (mBits & SideBits::eLeft) == SideBits::eLeft; }
+  bool Contains(SideBits aSideBits) const {
+    MOZ_ASSERT(!(aSideBits & ~SideBits::eAll), "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:
+  SideBits 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));
+  }
+
+  Sub& ApplySkipSides(Sides aSkipSides) {
+    if (aSkipSides.Top()) {
+      top = 0;
+    }
+    if (aSkipSides.Right()) {
+      right = 0;
+    }
+    if (aSkipSides.Bottom()) {
+      bottom = 0;
+    }
+    if (aSkipSides.Left()) {
+      left = 0;
+    }
+    return *static_cast<Sub*>(this);
+  }
+
+  // Ensures that all our sides are at least as big as the argument.
+  void EnsureAtLeast(const BaseMargin& aMargin) {
+    top = std::max(top, aMargin.top);
+    right = std::max(right, aMargin.right);
+    bottom = std::max(bottom, aMargin.bottom);
+    left = std::max(left, aMargin.left);
+  }
+
+  // Ensures that all our sides are at most as big as the argument.
+  void EnsureAtMost(const BaseMargin& aMargin) {
+    top = std::min(top, aMargin.top);
+    right = std::min(right, aMargin.right);
+    bottom = std::min(bottom, aMargin.bottom);
+    left = std::min(left, aMargin.left);
+  }
+
+  // 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 << "(t=" << aMargin.top << ", r=" << aMargin.right
+                   << ", b=" << aMargin.bottom << ", l=" << aMargin.left << ')';
+  }
+};
+
+}  // namespace gfx
+}  // namespace mozilla
+
+#endif /* MOZILLA_GFX_BASEMARGIN_H_ */