to_der

static VALUE ossl_ssl_session_to_der(VALUE self)
{
        SSL_SESSION *ctx;
        unsigned char *p;
        int len;
        VALUE str;

        GetSSLSession(self, ctx);
        len = i2d_SSL_SESSION(ctx, NULL);
        if (len <= 0) {
                ossl_raise(eSSLSession, "i2d_SSL_SESSION");
        }

        str = rb_str_new(0, len);
        p = (unsigned char *)RSTRING_PTR(str);
        i2d_SSL_SESSION(ctx, &p);
        ossl_str_adjust(str, p);
        return str;
}