gfx/2d/Tools.h
 author Sebastian Hengst Mon, 22 Oct 2018 16:33:06 +0300 changeset 442291 c44fbdd5173548c9035256dda8fd3512f67118a8 parent 440747 da3c96e21a15be08c937560c203b7abd2125ea1e child 448947 6f3709b3878117466168c40affa7bca0b60cf75b permissions -rw-r--r--
Bug 1496764 - Disable browser_UsageTelemetry_searchbar.js until telemetry probe has been extended to fix permafail on version increase. a=version-increase-fix
```
/* -*- 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 "mozilla/CheckedInt.h"
#include "mozilla/MemoryReporting.h" // for MallocSizeOf
#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 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
{
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(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);
}

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_ */
```
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