/** 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; }
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)); }
static bool isPos32Bits(const Sk64& value) { return !value.isNeg() && value.is32(); }