new

static VALUE
ossl_asn1_initialize(int argc, VALUE *argv, VALUE self)
{
    VALUE value, tag, tagging, tag_class;

    rb_scan_args(argc, argv, "13", &value, &tag, &tagging, &tag_class);
    if(argc > 1){
        if(NIL_P(tag))
            ossl_raise(eASN1Error, "must specify tag number");
        if(NIL_P(tagging))
            tagging = ID2SYM(sEXPLICIT);
        if(!SYMBOL_P(tagging))
            ossl_raise(eASN1Error, "invalid tag default");
        if(NIL_P(tag_class))
            tag_class = ID2SYM(sCONTEXT_SPECIFIC);
        if(!SYMBOL_P(tag_class))
            ossl_raise(eASN1Error, "invalid tag class");
        if(SYM2ID(tagging) == sIMPLICIT && NUM2INT(tag) > 31)
            ossl_raise(eASN1Error, "tag number for Universal too large");
    }
    else{
        tag = INT2NUM(ossl_asn1_default_tag(self));
        tagging = Qnil;
        tag_class = ID2SYM(sUNIVERSAL);
    }
    ossl_asn1_set_tag(self, tag);
    ossl_asn1_set_value(self, value);
    ossl_asn1_set_tagging(self, tagging);
    ossl_asn1_set_tag_class(self, tag_class);

    return self;
}