mirror of
https://github.com/classilla/tenfourfox.git
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222 lines
5.7 KiB
C++
222 lines
5.7 KiB
C++
/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef MOZILLA_GFX_TOOLS_H_
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#define MOZILLA_GFX_TOOLS_H_
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#include "mozilla/CheckedInt.h"
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#include "mozilla/Move.h"
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#include "mozilla/TypeTraits.h"
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#include "Types.h"
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#include "Point.h"
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#include <math.h>
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#if defined(_MSC_VER) && (_MSC_VER < 1600)
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#define hypotf _hypotf
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#endif
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namespace mozilla {
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namespace gfx {
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static inline bool
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IsOperatorBoundByMask(CompositionOp aOp) {
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switch (aOp) {
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case CompositionOp::OP_IN:
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case CompositionOp::OP_OUT:
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case CompositionOp::OP_DEST_IN:
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case CompositionOp::OP_DEST_ATOP:
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case CompositionOp::OP_SOURCE:
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return false;
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default:
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return true;
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}
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}
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template <class T>
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struct ClassStorage
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{
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char bytes[sizeof(T)];
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const T *addr() const { return (const T *)bytes; }
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T *addr() { return (T *)(void *)bytes; }
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};
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static inline bool
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FuzzyEqual(Float aA, Float aB, Float aErr)
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{
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if ((aA + aErr >= aB) && (aA - aErr <= aB)) {
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return true;
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}
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return false;
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}
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static inline void
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NudgeToInteger(float *aVal)
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{
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float r = floorf(*aVal + 0.5f);
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// The error threshold should be proportional to the rounded value. This
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// bounds the relative error introduced by the nudge operation. However,
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// when the rounded value is 0, the error threshold can't be proportional
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// to the rounded value (we'd never round), so we just choose the same
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// threshold as for a rounded value of 1.
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if (FuzzyEqual(r, *aVal, r == 0.0f ? 1e-6f : fabs(r*1e-6f))) {
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*aVal = r;
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}
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}
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static inline void
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NudgeToInteger(float *aVal, float aErr)
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{
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float r = floorf(*aVal + 0.5f);
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if (FuzzyEqual(r, *aVal, aErr)) {
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*aVal = r;
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}
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}
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static inline Float
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Distance(Point aA, Point aB)
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{
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return hypotf(aB.x - aA.x, aB.y - aA.y);
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}
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static inline int
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BytesPerPixel(SurfaceFormat aFormat)
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{
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switch (aFormat) {
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case SurfaceFormat::A8:
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return 1;
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case SurfaceFormat::R5G6B5_UINT16:
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return 2;
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default:
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return 4;
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}
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}
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template<typename T, int alignment = 16>
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struct AlignedArray
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{
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typedef T value_type;
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AlignedArray()
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: mPtr(nullptr)
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, mStorage(nullptr)
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{
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}
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explicit MOZ_ALWAYS_INLINE AlignedArray(size_t aCount, bool aZero = false)
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: mStorage(nullptr)
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, mCount(0)
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{
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Realloc(aCount, aZero);
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}
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MOZ_ALWAYS_INLINE ~AlignedArray()
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{
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Dealloc();
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}
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void Dealloc()
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{
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// If we fail this assert we'll need to uncomment the loop below to make
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// sure dtors are properly invoked. If we do that, we should check that the
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// comment about compiler dead code elimination is in fact true for all the
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// compilers that we care about.
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static_assert(mozilla::IsPod<T>::value,
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"Destructors must be invoked for this type");
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#if 0
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for (size_t i = 0; i < mCount; ++i) {
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// Since we used the placement |operator new| function to construct the
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// elements of this array we need to invoke their destructors manually.
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// For types where the destructor does nothing the compiler's dead code
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// elimination step should optimize this loop away.
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mPtr[i].~T();
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}
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#endif
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free(mStorage);
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mStorage = nullptr;
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mPtr = nullptr;
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}
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MOZ_ALWAYS_INLINE void Realloc(size_t aCount, bool aZero = false)
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{
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free(mStorage);
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CheckedInt32 storageByteCount =
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CheckedInt32(sizeof(T)) * aCount + (alignment - 1);
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if (!storageByteCount.isValid()) {
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mStorage = nullptr;
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mPtr = nullptr;
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mCount = 0;
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return;
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}
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// We don't create an array of T here, since we don't want ctors to be
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// invoked at the wrong places if we realign below.
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if (aZero) {
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// calloc can be more efficient than new[] for large chunks,
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// so we use calloc/malloc/free for everything.
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mStorage = static_cast<uint8_t *>(calloc(1, storageByteCount.value()));
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} else {
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mStorage = static_cast<uint8_t *>(malloc(storageByteCount.value()));
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}
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if (!mStorage) {
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mStorage = nullptr;
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mPtr = nullptr;
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mCount = 0;
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return;
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}
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if (uintptr_t(mStorage) % alignment) {
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// Our storage does not start at a <alignment>-byte boundary. Make sure mPtr does!
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mPtr = (T*)(uintptr_t(mStorage) + alignment - (uintptr_t(mStorage) % alignment));
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} else {
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mPtr = (T*)(mStorage);
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}
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// Now that mPtr is pointing to the aligned position we can use placement
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// |operator new| to invoke any ctors at the correct positions. For types
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// that have a no-op default constructor the compiler's dead code
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// elimination step should optimize this away.
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mPtr = new (mPtr) T[aCount];
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mCount = aCount;
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}
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void Swap(AlignedArray<T, alignment>& aOther)
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{
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mozilla::Swap(mPtr, aOther.mPtr);
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mozilla::Swap(mStorage, aOther.mStorage);
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mozilla::Swap(mCount, aOther.mCount);
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}
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MOZ_ALWAYS_INLINE operator T*()
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{
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return mPtr;
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}
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T *mPtr;
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private:
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uint8_t *mStorage;
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size_t mCount;
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};
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/**
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* Returns aStride increased, if necessary, so that it divides exactly into
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* |alignment|.
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*
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* Note that currently |alignment| must be a power-of-2. If for some reason we
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* want to support NPOT alignment we can revert back to this functions old
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* implementation.
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*/
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template<int alignment>
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int32_t GetAlignedStride(int32_t aStride)
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{
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static_assert(alignment > 0 && (alignment & (alignment-1)) == 0,
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"This implementation currently require power-of-two alignment");
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const int32_t mask = alignment - 1;
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return (aStride + mask) & ~mask;
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}
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} // namespace gfx
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} // namespace mozilla
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#endif /* MOZILLA_GFX_TOOLS_H_ */
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