add_data

static VALUE
ossl_pkcs7_add_data(VALUE self, VALUE data)
{
    PKCS7 *pkcs7;
    BIO *out, *in;
    char buf[4096];
    int len;

    GetPKCS7(self, pkcs7);
    if(PKCS7_type_is_signed(pkcs7)){
        if(!PKCS7_content_new(pkcs7, NID_pkcs7_data))
            ossl_raise(ePKCS7Error, NULL);
    }
    in = ossl_obj2bio(&data);
    if(!(out = PKCS7_dataInit(pkcs7, NULL))) goto err;
    for(;;){
        if((len = BIO_read(in, buf, sizeof(buf))) <= 0)
            break;
        if(BIO_write(out, buf, len) != len)
            goto err;
    }
    if(!PKCS7_dataFinal(pkcs7, out)) goto err;
    ossl_pkcs7_set_data(self, Qnil);

 err:
    BIO_free_all(out);
    BIO_free(in);
    if(ERR_peek_error()){
        ossl_raise(ePKCS7Error, NULL);
    }

    return data;
}