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authoraliguori <aliguori@c046a42c-6fe2-441c-8c8c-71466251a162>2009-02-02 15:58:54 +0000
committeraliguori <aliguori@c046a42c-6fe2-441c-8c8c-71466251a162>2009-02-02 15:58:54 +0000
commit059cef4092cc1f558f8f74cf2f762cef41237434 (patch)
tree738495ff88ecd3687e83378e69feb48b11afc472 /vnc.c
parentMove the framebuffer update package out (Alexander Graf) (diff)
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Add zlib encoding support (Alexander Graf)
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
Diffstat (limited to 'vnc.c')
-rw-r--r--vnc.c109
1 files changed, 109 insertions, 0 deletions
diff --git a/vnc.c b/vnc.c
index f5235ab8f..0c4d96e25 100644
--- a/vnc.c
+++ b/vnc.c
@@ -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;