params

static VALUE
rb_deflate_params(VALUE obj, VALUE v_level, VALUE v_strategy)
{
    struct zstream *z = get_zstream(obj);
    int level, strategy;
    int err;

    level = ARG_LEVEL(v_level);
    strategy = ARG_STRATEGY(v_strategy);

    zstream_run(z, (Bytef*)"", 0, Z_SYNC_FLUSH);
    err = deflateParams(&z->stream, level, strategy);
    while (err == Z_BUF_ERROR) {
        rb_warning("deflateParams() returned Z_BUF_ERROR");
        zstream_expand_buffer(z);
        err = deflateParams(&z->stream, level, strategy);
    }
    if (err != Z_OK) {
        raise_zlib_error(err, z->stream.msg);
    }

    return Qnil;
}