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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_TOOLS_H_
#define MOZILLA_GFX_TOOLS_H_
#include <math.h>
#include <utility>
#include "Point.h"
#include "Types.h"
#include "mozilla/CheckedInt.h"
#include "mozilla/MemoryReporting.h" // for MallocSizeOf
#include "mozilla/TypeTraits.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 void NudgeToInteger(double* aVal) {
float f = float(*aVal);
NudgeToInteger(&f);
*aVal = f;
}
static inline Float Distance(Point aA, Point aB) {
return hypotf(aB.x - aA.x, aB.y - aA.y);
}
template <typename T, int alignment = 16>
struct AlignedArray final {
typedef T value_type;
AlignedArray() : mPtr(nullptr), mStorage(nullptr), mCount(0) {}
explicit MOZ_ALWAYS_INLINE AlignedArray(size_t aCount, bool aZero = false)
: mPtr(nullptr), 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(1u, 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) {
std::swap(mPtr, aOther.mPtr);
std::swap(mStorage, aOther.mStorage);
std::swap(mCount, aOther.mCount);
}
size_t HeapSizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const {
return aMallocSizeOf(mStorage);
}
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_ */