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/*
* QEMU VNC display driver: zlib encoding
*
* Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>
* Copyright (C) 2006 Fabrice Bellard
* Copyright (C) 2009 Red Hat, Inc
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "vnc.h"
#define ZALLOC_ALIGNMENT 16
static void *zalloc(void *x, unsigned items, unsigned size)
{
void *p;
size *= items;
size = (size + ZALLOC_ALIGNMENT - 1) & ~(ZALLOC_ALIGNMENT - 1);
p = qemu_mallocz(size);
return (p);
}
static void zfree(void *x, void *addr)
{
qemu_free(addr);
}
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)
{
z_streamp zstream = &vs->zlib_stream;
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\n");
VNC_DEBUG("VNC: opaque = %p | vs = %p\n", zstream->opaque, vs);
zstream->zalloc = zalloc;
zstream->zfree = zfree;
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;
}
void vnc_zlib_send_framebuffer_update(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);
vnc_raw_send_framebuffer_update(vs, x, y, w, h);
bytes_written = vnc_zlib_stop(vs);
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;
}
void vnc_zlib_init(VncState *vs)
{
vs->zlib_stream.opaque = NULL;
}
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