Function stbi__mul2shorts_valid

Source/Utils/stb_image.h:1077–1083

returns 1 if the product of two ints fits in a signed short, 0 on overflow.

// returns 1 if the product of two ints fits in a signed short, 0 on overflow.
static int stbi__mul2shorts_valid(int a, int b)
{
   if (b == 0 || b == -1) return 1; // multiplication by 0 is always 0; check for -1 so SHRT_MIN/b doesn't overflow
   if ((a >= 0) == (b >= 0)) return a <= SHRT_MAX/b; // product is positive, so similar to mul2sizes_valid
   if (b < 0) return a <= SHRT_MIN / b; // same as a * b >= SHRT_MIN
   return a >= SHRT_MIN / b;
}

// stbi__err - error
// stbi__errpf - error returning pointer to float