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+/* -*- 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 "mozilla/CheckedInt.h"
+#include "mozilla/Move.h"
+#include "mozilla/TypeTraits.h"
+#include "Types.h"
+#include "Point.h"
+#include <math.h>
+
+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 void
+NudgeToInteger(float *aVal, float aErr)
+{
+ float r = floorf(*aVal + 0.5f);
+ if (FuzzyEqual(r, *aVal, aErr)) {
+ *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_UINT16:
+ return 2;
+ case SurfaceFormat::R8G8B8:
+ case SurfaceFormat::B8G8R8:
+ return 3;
+ case SurfaceFormat::HSV:
+ case SurfaceFormat::Lab:
+ return 3 * sizeof(float);
+ case SurfaceFormat::Depth:
+ return sizeof(uint16_t);
+ default:
+ return 4;
+ }
+}
+
+static inline bool
+IsOpaqueFormat(SurfaceFormat aFormat) {
+ switch (aFormat) {
+ case SurfaceFormat::B8G8R8X8:
+ case SurfaceFormat::R8G8B8X8:
+ case SurfaceFormat::X8R8G8B8:
+ case SurfaceFormat::YUV:
+ case SurfaceFormat::NV12:
+ case SurfaceFormat::YUV422:
+ case SurfaceFormat::R5G6B5_UINT16:
+ return true;
+ default:
+ return false;
+ }
+}
+
+template<typename T, int alignment = 16>
+struct AlignedArray
+{
+ typedef T value_type;
+
+ AlignedArray()
+ : mPtr(nullptr)
+ , mStorage(nullptr)
+ {
+ }
+
+ explicit MOZ_ALWAYS_INLINE AlignedArray(size_t aCount, bool aZero = false)
+ : mStorage(nullptr)
+ , mCount(0)
+ {
+ Realloc(aCount, aZero);
+ }
+
+ MOZ_ALWAYS_INLINE ~AlignedArray()
+ {
+ Dealloc();
+ }
+
+ void Dealloc()
+ {
+ // If we fail this assert we'll need to uncomment the loop below to make
+ // sure dtors are properly invoked. If we do that, we should check that the
+ // comment about compiler dead code elimination is in fact true for all the
+ // compilers that we care about.
+ static_assert(mozilla::IsPod<T>::value,
+ "Destructors must be invoked for this type");
+#if 0
+ for (size_t i = 0; i < mCount; ++i) {
+ // Since we used the placement |operator new| function to construct the
+ // elements of this array we need to invoke their destructors manually.
+ // For types where the destructor does nothing the compiler's dead code
+ // elimination step should optimize this loop away.
+ mPtr[i].~T();
+ }
+#endif
+
+ free(mStorage);
+ mStorage = nullptr;
+ mPtr = nullptr;
+ }
+
+ MOZ_ALWAYS_INLINE void Realloc(size_t aCount, bool aZero = false)
+ {
+ free(mStorage);
+ CheckedInt32 storageByteCount =
+ CheckedInt32(sizeof(T)) * aCount + (alignment - 1);
+ if (!storageByteCount.isValid()) {
+ mStorage = nullptr;
+ mPtr = nullptr;
+ mCount = 0;
+ return;
+ }
+ // We don't create an array of T here, since we don't want ctors to be
+ // invoked at the wrong places if we realign below.
+ if (aZero) {
+ // calloc can be more efficient than new[] for large chunks,
+ // so we use calloc/malloc/free for everything.
+ mStorage = static_cast<uint8_t *>(calloc(1, storageByteCount.value()));
+ } else {
+ mStorage = static_cast<uint8_t *>(malloc(storageByteCount.value()));
+ }
+ if (!mStorage) {
+ mStorage = nullptr;
+ mPtr = nullptr;
+ mCount = 0;
+ return;
+ }
+ if (uintptr_t(mStorage) % alignment) {
+ // Our storage does not start at a <alignment>-byte boundary. Make sure mPtr does!
+ mPtr = (T*)(uintptr_t(mStorage) + alignment - (uintptr_t(mStorage) % alignment));
+ } else {
+ mPtr = (T*)(mStorage);
+ }
+ // Now that mPtr is pointing to the aligned position we can use placement
+ // |operator new| to invoke any ctors at the correct positions. For types
+ // that have a no-op default constructor the compiler's dead code
+ // elimination step should optimize this away.
+ mPtr = new (mPtr) T[aCount];
+ mCount = aCount;
+ }
+
+ void Swap(AlignedArray<T, alignment>& aOther)
+ {
+ mozilla::Swap(mPtr, aOther.mPtr);
+ mozilla::Swap(mStorage, aOther.mStorage);
+ mozilla::Swap(mCount, aOther.mCount);
+ }
+
+ MOZ_ALWAYS_INLINE operator T*()
+ {
+ return mPtr;
+ }
+
+ T *mPtr;
+
+private:
+ uint8_t *mStorage;
+ size_t mCount;
+};
+
+/**
+ * Returns aWidth * aBytesPerPixel increased, if necessary, so that it divides
+ * exactly into |alignment|.
+ *
+ * Note that currently |alignment| must be a power-of-2. If for some reason we
+ * want to support NPOT alignment we can revert back to this functions old
+ * implementation.
+ */
+template<int alignment>
+int32_t GetAlignedStride(int32_t aWidth, int32_t aBytesPerPixel)
+{
+ static_assert(alignment > 0 && (alignment & (alignment-1)) == 0,
+ "This implementation currently require power-of-two alignment");
+ const int32_t mask = alignment - 1;
+ CheckedInt32 stride = CheckedInt32(aWidth) * CheckedInt32(aBytesPerPixel) + CheckedInt32(mask);
+ if (stride.isValid()) {
+ return stride.value() & ~mask;
+ }
+ return 0;
+}
+
+} // namespace gfx
+} // namespace mozilla
+
+#endif /* MOZILLA_GFX_TOOLS_H_ */