// Returns the square of the Euclidian distance to (dx,dy) in *result.
static inline void getLengthSquared(SkScalar dx, SkScalar dy, Sk64 *result) {
Sk64 dySqr;
result->setMul(dx, dx);
dySqr.setMul(dy, dy);
result->add(dySqr);
}
/** returns the product if it is positive and fits in 31 bits. Otherwise this
returns 0.
*/
static int32_t safeMul32(int32_t a, int32_t b) {
Sk64 size;
size.setMul(a, b);
if (size.is32() && size.isPos()) {
return size.get32();
}
return 0;
}
SkMSec SkTime::GetMSecs()
{
UnsignedWide wide;
Sk64 s;
::Microseconds(&wide);
s.set(wide.hi, wide.lo);
s.div(1000, Sk64::kRound_DivOption);
return s.get32();
}
// Calculates the square of the Euclidian distance to (dx,dy) and stores it in
// *lengthSquared. Returns true if the distance is judged to be "nearly zero".
//
// This logic is encapsulated in a helper method to make it explicit that we
// always perform this check in the same manner, to avoid inconsistencies
// (see http://code.google.com/p/skia/issues/detail?id=560 ).
static inline bool isLengthNearlyZero(SkScalar dx, SkScalar dy,
Sk64 *lengthSquared) {
Sk64 tolSqr;
getLengthSquared(dx, dy, lengthSquared);
// we want nearlyzero^2, but to compute it fast we want to just do a
// 32bit multiply, so we require that it not exceed 31bits. That is true
// if nearlyzero is <= 0xB504, which should be trivial, since usually
// nearlyzero is a very small fixed-point value.
SkASSERT(SK_ScalarNearlyZero <= 0xB504);
tolSqr.set(0, SK_ScalarNearlyZero * SK_ScalarNearlyZero);
return *lengthSquared <= tolSqr;
}
static MipMap* Alloc(int levelCount, size_t pixelSize) {
if (levelCount < 0) {
return NULL;
}
Sk64 size;
size.setMul(levelCount + 1, sizeof(MipLevel));
size.add(sizeof(MipMap));
size.add(pixelSize);
if (!isPos32Bits(size)) {
return NULL;
}
MipMap* mm = (MipMap*)sk_malloc_throw(size.get32());
mm->fRefCnt = 1;
mm->fLevelCount = levelCount;
return mm;
}
SkMallocPixelRef* SkMallocPixelRef::NewAllocate(const SkImageInfo& info,
size_t requestedRowBytes,
SkColorTable* ctable) {
if (!is_valid(info, ctable)) {
return NULL;
}
int32_t minRB = info.minRowBytes();
if (minRB < 0) {
return NULL; // allocation will be too large
}
if (requestedRowBytes > 0 && (int32_t)requestedRowBytes < minRB) {
return NULL; // cannot meet requested rowbytes
}
int32_t rowBytes;
if (requestedRowBytes) {
rowBytes = requestedRowBytes;
} else {
rowBytes = minRB;
}
Sk64 bigSize;
bigSize.setMul(info.fHeight, rowBytes);
if (!bigSize.is32()) {
return NULL;
}
size_t size = bigSize.get32();
void* addr = sk_malloc_flags(size, 0);
if (NULL == addr) {
return NULL;
}
return SkNEW_ARGS(SkMallocPixelRef, (info, addr, rowBytes, ctable, true));
}
/** Trim A/B/C down so that they are all <= 32bits
and then call SkFindUnitQuadRoots()
*/
static int Sk64FindFixedQuadRoots(const Sk64& A, const Sk64& B, const Sk64& C, SkFixed roots[2])
{
int na = A.shiftToMake32();
int nb = B.shiftToMake32();
int nc = C.shiftToMake32();
int shift = SkMax32(na, SkMax32(nb, nc));
SkASSERT(shift >= 0);
return SkFindUnitQuadRoots(A.getShiftRight(shift), B.getShiftRight(shift), C.getShiftRight(shift), roots);
}
static bool isPos32Bits(const Sk64& value) {
return !value.isNeg() && value.is32();
}
SkScalar SkPoint::Length(SkScalar dx, SkScalar dy) {
Sk64 tmp;
getLengthSquared(dx, dy, &tmp);
return tmp.getSqrt();
}
