/* -*- 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_ */