new

/*
 * call-seq: Zlib::Deflate.new(level=nil, windowBits=nil, memlevel=nil, strategy=nil)
 *
 * Creates a new deflate stream for compression. See zlib.h for details of
 * each argument. If an argument is nil, the default value of that argument is
 * used.
 *
 * TODO: document better!
 */
static VALUE
rb_deflate_initialize(argc, argv, obj)
    int argc;
    VALUE *argv;
    VALUE obj;
{
    struct zstream *z;
    VALUE level, wbits, memlevel, strategy;
    int err;

    rb_scan_args(argc, argv, "04", &level, &wbits, &memlevel, &strategy);
    Data_Get_Struct(obj, struct zstream, z);

    err = deflateInit2(&z->stream, ARG_LEVEL(level), Z_DEFLATED,
                       ARG_WBITS(wbits), ARG_MEMLEVEL(memlevel),
                       ARG_STRATEGY(strategy));
    if (err != Z_OK) {
        raise_zlib_error(err, z->stream.msg);
    }
    ZSTREAM_READY(z);

    return obj;
}