On Sun, Jan 29, 2012 at 09:28:34AM +0200, Yaniv Kaul wrote:
> These small changes to server and (gtk) client seem to work, and
> remove both the zlib header/trailer from the deflate stream as well
> as the Adler checksum, which removes several bytes from the stream
> as well as speedup (unnoticeable) of the compression/decompression
> due to the removal of the checksum calculation.
>
> Problem is - not sure how to test it - don't know how to get an
> image once with and once without the patch - and ensure it's the
> same image.
> The fact that the first image is never zlib compressed complicates
> things. I could not reliably get a 2nd image sent to the client
> which looks the same as one in a different connection.
>
> Nevertheless it does no harm - and images pass well - verified by
> connecting with a modified Spice GTK client to a modified Spice
> server, as well as looking at the network capture via wireshark.
>
> It's of course missing the display channel specific capability
> negotiation for this change.
> Comments are welcome.
Other then that adding a link to the docs page of
inlateInit2/deflateInit2 in the commit message would be nice for those
seeking to find the explanation for the magic numbers, no comment,
thanks for doing this!
If you want a repeatable test you can write one or use one of the
existing artificial tests in server/tests.
>
> Client change:
> diff --git a/gtk/decode-zlib.c b/gtk/decode-zlib.c
> index a692020..997f350 100644
> --- a/gtk/decode-zlib.c
> +++ b/gtk/decode-zlib.c
> @@ -63,7 +63,7 @@ SpiceZlibDecoder *zlib_decoder_new(void)
> d->_z_strm.opaque = Z_NULL;
> d->_z_strm.next_in = Z_NULL;
> d->_z_strm.avail_in = 0;
> - z_ret = inflateInit(&d->_z_strm);
> + z_ret = inflateInit2(&d->_z_strm, -15);
> if (z_ret != Z_OK) {
> g_warning("zlib decoder init failed, error %d", z_ret);
> goto fail;
>
>
> server change:
> diff --git a/server/zlib_encoder.c b/server/zlib_encoder.c
> index c51466b..66a039a 100644
> --- a/server/zlib_encoder.c
> +++ b/server/zlib_encoder.c
> @@ -47,7 +47,7 @@ ZlibEncoder*
> zlib_encoder_create(ZlibEncoderUsrContext *usr, int level)
> enc->strm.zfree = Z_NULL;
> enc->strm.opaque = Z_NULL;
>
> - z_ret = deflateInit(&enc->strm, level);
> + z_ret = deflateInit2(&enc->strm, level, Z_DEFLATED, -15, 8,
> Z_DEFAULT_STRATEGY);
> enc->last_level = level;
> if (z_ret != Z_OK) {
> red_printf("zlib error");
> _______________________________________________
> Spice-devel mailing list
> Spice-devel@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/spice-devel
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