ReadSInt32
if (!fStream->ReadSInt32(attr.val.sint32)) return NULL;
if (!fStream->ReadSInt32(attr.val.SInt32_XY.x) || !fStream->ReadSInt32(attr.val.SInt32_XY.y)) return NULL;
if (!fStream->ReadSInt32(attr.val.SInt32_BOX.x1) || !fStream->ReadSInt32(attr.val.SInt32_BOX.y1) ||
!fStream->ReadSInt32(attr.val.SInt32_BOX.x2) || !fStream->ReadSInt32(attr.val.SInt32_BOX.y2)) return NULL;
bool ReadSInt32(int32& v);