GfxShadingPattern *GfxShadingPattern::parse(Object *patObj) {
  Dict *dict;
  GfxShading *shadingA;
  double matrixA[6];
  Object obj1, obj2;
  int i;

  if (!patObj->isDict()) {
    return NULL;
  }
  dict = patObj->getDict();

  dict->lookup("Shading", &obj1);
  shadingA = GfxShading::parse(&obj1);
  obj1.free();
  if (!shadingA) {
    return NULL;
  }

  matrixA[0] = 1; matrixA[1] = 0;
  matrixA[2] = 0; matrixA[3] = 1;
  matrixA[4] = 0; matrixA[5] = 0;
  if (dict->lookup("Matrix", &obj1)->isArray() &&
      obj1.arrayGetLength() == 6) {
    for (i = 0; i < 6; ++i) {
      if (obj1.arrayGet(i, &obj2)->isNum()) {
	matrixA[i] = obj2.getNum();
      }
      obj2.free();
    }
  }
  obj1.free();

  return new GfxShadingPattern(shadingA, matrixA);
}

This weakness involves numeric computation errors, such as integer overflows, underflows, or precision losses, which can lead to miscalculations and exploitable behaviors in software.