new

static VALUE
ossl_x509ext_initialize(int argc, VALUE *argv, VALUE self)
{
    VALUE oid, value, critical;
    const unsigned char *p;
    X509_EXTENSION *ext, *x;

    GetX509Ext(self, ext);
    if(rb_scan_args(argc, argv, "12", &oid, &value, &critical) == 1){
        oid = ossl_to_der_if_possible(oid);
        StringValue(oid);
        p = (unsigned char *)RSTRING_PTR(oid);
        x = d2i_X509_EXTENSION(&ext, &p, RSTRING_LEN(oid));
        DATA_PTR(self) = ext;
        if(!x)
            ossl_raise(eX509ExtError, NULL);
        return self;
    }
    rb_funcall(self, rb_intern("oid="), 1, oid);
    rb_funcall(self, rb_intern("value="), 1, value);
    if(argc > 2) rb_funcall(self, rb_intern("critical="), 1, critical);

    return self;
}