mirrors/qemu
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Add zlib encoding support (Alexander Graf)

Browse Source 
This patch adds zlib encoding support for VNC. It basically runs
the raw traffic through zlib, providing a pretty good compression
ratio.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6499 c046a42c-6fe2-441c-8c8c-71466251a162
This commit is contained in:
aliguori 2009-02-02 15:58:54 +00:00
parent d2a0102a4c
commit 059cef4092
1 changed files with 109 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

109
vnc.c
View File

@ -29,6 +29,7 @@
#include "qemu_socket.h"
#include "qemu-timer.h"
#include "audio/audio.h"
#include <zlib.h>
#define VNC_REFRESH_INTERVAL (1000 / 30)
@ -144,6 +145,10 @@ struct VncState
size_t read_handler_expect;
/* input */
uint8_t modifiers_state[256];
Buffer zlib;
Buffer zlib_tmp;
z_stream zlib_stream[4];
};
static VncState *vnc_state; /* needed for info vnc */
@ -481,9 +486,108 @@ static void send_framebuffer_update_hextile(VncState *vs, int x, int y, int w, i
}
static void vnc_zlib_init(VncState *vs)
{
int i;
for (i=0; i<(sizeof(vs->zlib_stream) / sizeof(z_stream)); i++)
vs->zlib_stream[i].opaque = NULL;
}
static void vnc_zlib_start(VncState *vs)
{
buffer_reset(&vs->zlib);
// make the output buffer be the zlib buffer, so we can compress it later
vs->zlib_tmp = vs->output;
vs->output = vs->zlib;
}
static int vnc_zlib_stop(VncState *vs, int stream_id)
{
z_streamp zstream = &vs->zlib_stream[stream_id];
int previous_out;
// switch back to normal output/zlib buffers
vs->zlib = vs->output;
vs->output = vs->zlib_tmp;
// compress the zlib buffer
// initialize the stream
// XXX need one stream per session
if (zstream->opaque != vs) {
int err;
VNC_DEBUG("VNC: initializing zlib stream %d\n", stream_id);
VNC_DEBUG("VNC: opaque = %p | vs = %p\n", zstream->opaque, vs);
zstream->zalloc = Z_NULL;
zstream->zfree = Z_NULL;
err = deflateInit2(zstream, vs->tight_compression, Z_DEFLATED, MAX_WBITS,
MAX_MEM_LEVEL, Z_DEFAULT_STRATEGY);
if (err != Z_OK) {
fprintf(stderr, "VNC: error initializing zlib\n");
return -1;
}
zstream->opaque = vs;
}
// XXX what to do if tight_compression changed in between?
// reserve memory in output buffer
buffer_reserve(&vs->output, vs->zlib.offset + 64);
// set pointers
zstream->next_in = vs->zlib.buffer;
zstream->avail_in = vs->zlib.offset;
zstream->next_out = vs->output.buffer + vs->output.offset;
zstream->avail_out = vs->output.capacity - vs->output.offset;
zstream->data_type = Z_BINARY;
previous_out = zstream->total_out;
// start encoding
if (deflate(zstream, Z_SYNC_FLUSH) != Z_OK) {
fprintf(stderr, "VNC: error during zlib compression\n");
return -1;
}
vs->output.offset = vs->output.capacity - zstream->avail_out;
return zstream->total_out - previous_out;
}
static void send_framebuffer_update_zlib(VncState *vs, int x, int y, int w, int h)
{
int old_offset, new_offset, bytes_written;
vnc_framebuffer_update(vs, x, y, w, h, VNC_ENCODING_ZLIB);
// remember where we put in the follow-up size
old_offset = vs->output.offset;
vnc_write_s32(vs, 0);
// compress the stream
vnc_zlib_start(vs);
send_framebuffer_update_raw(vs, x, y, w, h);
bytes_written = vnc_zlib_stop(vs, 0);
if (bytes_written == -1)
return;
// hack in the size
new_offset = vs->output.offset;
vs->output.offset = old_offset;
vnc_write_u32(vs, bytes_written);
vs->output.offset = new_offset;
}
static void send_framebuffer_update(VncState *vs, int x, int y, int w, int h)
{
switch(vs->vnc_encoding) {
case VNC_ENCODING_ZLIB:
send_framebuffer_update_zlib(vs, x, y, w, h);
break;
case VNC_ENCODING_HEXTILE:
vnc_framebuffer_update(vs, x, y, w, h, VNC_ENCODING_HEXTILE);
send_framebuffer_update_hextile(vs, x, y, w, h);
@ -1169,6 +1273,7 @@ static void set_encodings(VncState *vs, int32_t *encodings, size_t n_encodings)
int i;
unsigned int enc = 0;
vnc_zlib_init(vs);
vs->features = 0;
vs->vnc_encoding = 0;
vs->tight_compression = 9;
@ -1189,6 +1294,10 @@ static void set_encodings(VncState *vs, int32_t *encodings, size_t n_encodings)
vs->features |= VNC_FEATURE_HEXTILE_MASK;
vs->vnc_encoding = enc;
break;
case VNC_ENCODING_ZLIB:
vs->features |= VNC_FEATURE_ZLIB_MASK;
vs->vnc_encoding = enc;
break;
case VNC_ENCODING_DESKTOPRESIZE:
vs->features |= VNC_FEATURE_RESIZE_MASK;
break;