diff -r 000000000000 -r 6474c204b198 gfx/2d/Tools.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/2d/Tools.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,145 @@
+/* -*- Mode: C++; tab-width: 20; 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_TOOLS_H_
+#define MOZILLA_GFX_TOOLS_H_
+
+#include "Types.h"
+#include "Point.h"
+#include <math.h>
+#if defined(_MSC_VER) && (_MSC_VER < 1600)
+#define hypotf _hypotf
+#endif
+
+namespace mozilla {
+namespace gfx {
+
+static inline bool
+IsOperatorBoundByMask(CompositionOp aOp) {
+  switch (aOp) {
+  case CompositionOp::OP_IN:
+  case CompositionOp::OP_OUT:
+  case CompositionOp::OP_DEST_IN:
+  case CompositionOp::OP_DEST_ATOP:
+  case CompositionOp::OP_SOURCE:
+    return false;
+  default:
+    return true;
+  }
+}
+
+template <class T>
+struct ClassStorage
+{
+  char bytes[sizeof(T)];
+
+  const T *addr() const { return (const T *)bytes; }
+  T *addr() { return (T *)(void *)bytes; }
+};
+
+static inline bool
+FuzzyEqual(Float aA, Float aB, Float aErr)
+{
+  if ((aA + aErr >= aB) && (aA - aErr <= aB)) {
+    return true;
+  }
+  return false;
+}
+
+static inline void
+NudgeToInteger(float *aVal)
+{
+  float r = floorf(*aVal + 0.5f);
+  // The error threshold should be proportional to the rounded value. This
+  // bounds the relative error introduced by the nudge operation. However,
+  // when the rounded value is 0, the error threshold can't be proportional
+  // to the rounded value (we'd never round), so we just choose the same
+  // threshold as for a rounded value of 1.
+  if (FuzzyEqual(r, *aVal, r == 0.0f ? 1e-6f : fabs(r*1e-6f))) {
+    *aVal = r;
+  }
+}
+
+static inline Float
+Distance(Point aA, Point aB)
+{
+  return hypotf(aB.x - aA.x, aB.y - aA.y);
+}
+
+static inline int
+BytesPerPixel(SurfaceFormat aFormat)
+{
+  switch (aFormat) {
+  case SurfaceFormat::A8:
+    return 1;
+  case SurfaceFormat::R5G6B5:
+    return 2;
+  default:
+    return 4;
+  }
+}
+
+template<typename T, int alignment = 16>
+struct AlignedArray
+{
+  AlignedArray()
+    : mStorage(nullptr)
+    , mPtr(nullptr)
+  {
+  }
+
+  MOZ_ALWAYS_INLINE AlignedArray(size_t aSize)
+    : mStorage(nullptr)
+  {
+    Realloc(aSize);
+  }
+
+  MOZ_ALWAYS_INLINE ~AlignedArray()
+  {
+    delete [] mStorage;
+  }
+
+  void Dealloc()
+  {
+    delete [] mStorage;
+    mStorage = mPtr = nullptr;
+  }
+
+  MOZ_ALWAYS_INLINE void Realloc(size_t aSize)
+  {
+    delete [] mStorage;
+    mStorage = new (std::nothrow) T[aSize + (alignment - 1)];
+    if (uintptr_t(mStorage) % alignment) {
+      // Our storage does not start at a <alignment>-byte boundary. Make sure mData does!
+      mPtr = (T*)(uintptr_t(mStorage) +
+        (alignment - (uintptr_t(mStorage) % alignment)));
+    } else {
+      mPtr = mStorage;
+    }
+  }
+
+  MOZ_ALWAYS_INLINE operator T*()
+  {
+    return mPtr;
+  }
+
+  T *mStorage;
+  T *mPtr;
+};
+
+template<int alignment>
+int32_t GetAlignedStride(int32_t aStride)
+{
+  if (aStride % alignment) {
+    return aStride + (alignment - (aStride % alignment));
+  }
+
+  return aStride;
+}
+
+}
+}
+
+#endif /* MOZILLA_GFX_TOOLS_H_ */