qemu

FORK: QEMU emulator
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vnc-enc-zlib.c (4583B)

      1 /*
      2  * QEMU VNC display driver: zlib encoding
      3  *
      4  * Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>
      5  * Copyright (C) 2006 Fabrice Bellard
      6  * Copyright (C) 2009 Red Hat, Inc
      7  *
      8  * Permission is hereby granted, free of charge, to any person obtaining a copy
      9  * of this software and associated documentation files (the "Software"), to deal
     10  * in the Software without restriction, including without limitation the rights
     11  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     12  * copies of the Software, and to permit persons to whom the Software is
     13  * furnished to do so, subject to the following conditions:
     14  *
     15  * The above copyright notice and this permission notice shall be included in
     16  * all copies or substantial portions of the Software.
     17  *
     18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     20  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
     21  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
     22  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
     23  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
     24  * THE SOFTWARE.
     25  */
     26 
     27 #include "qemu/osdep.h"
     28 #include "vnc.h"
     29 
     30 #define ZALLOC_ALIGNMENT 16
     31 
     32 void *vnc_zlib_zalloc(void *x, unsigned items, unsigned size)
     33 {
     34     void *p;
     35 
     36     size *= items;
     37     size = (size + ZALLOC_ALIGNMENT - 1) & ~(ZALLOC_ALIGNMENT - 1);
     38 
     39     p = g_malloc0(size);
     40 
     41     return (p);
     42 }
     43 
     44 void vnc_zlib_zfree(void *x, void *addr)
     45 {
     46     g_free(addr);
     47 }
     48 
     49 static void vnc_zlib_start(VncState *vs)
     50 {
     51     buffer_reset(&vs->zlib.zlib);
     52 
     53     // make the output buffer be the zlib buffer, so we can compress it later
     54     vs->zlib.tmp = vs->output;
     55     vs->output = vs->zlib.zlib;
     56 }
     57 
     58 static int vnc_zlib_stop(VncState *vs)
     59 {
     60     z_streamp zstream = &vs->zlib.stream;
     61     int previous_out;
     62 
     63     // switch back to normal output/zlib buffers
     64     vs->zlib.zlib = vs->output;
     65     vs->output = vs->zlib.tmp;
     66 
     67     // compress the zlib buffer
     68 
     69     // initialize the stream
     70     // XXX need one stream per session
     71     if (zstream->opaque != vs) {
     72         int err;
     73 
     74         VNC_DEBUG("VNC: initializing zlib stream\n");
     75         VNC_DEBUG("VNC: opaque = %p | vs = %p\n", zstream->opaque, vs);
     76         zstream->zalloc = vnc_zlib_zalloc;
     77         zstream->zfree = vnc_zlib_zfree;
     78 
     79         err = deflateInit2(zstream, vs->tight->compression, Z_DEFLATED,
     80                            MAX_WBITS,
     81                            MAX_MEM_LEVEL, Z_DEFAULT_STRATEGY);
     82 
     83         if (err != Z_OK) {
     84             fprintf(stderr, "VNC: error initializing zlib\n");
     85             return -1;
     86         }
     87 
     88         vs->zlib.level = vs->tight->compression;
     89         zstream->opaque = vs;
     90     }
     91 
     92     if (vs->tight->compression != vs->zlib.level) {
     93         if (deflateParams(zstream, vs->tight->compression,
     94                           Z_DEFAULT_STRATEGY) != Z_OK) {
     95             return -1;
     96         }
     97         vs->zlib.level = vs->tight->compression;
     98     }
     99 
    100     // reserve memory in output buffer
    101     buffer_reserve(&vs->output, vs->zlib.zlib.offset + 64);
    102 
    103     // set pointers
    104     zstream->next_in = vs->zlib.zlib.buffer;
    105     zstream->avail_in = vs->zlib.zlib.offset;
    106     zstream->next_out = vs->output.buffer + vs->output.offset;
    107     zstream->avail_out = vs->output.capacity - vs->output.offset;
    108     previous_out = zstream->avail_out;
    109     zstream->data_type = Z_BINARY;
    110 
    111     // start encoding
    112     if (deflate(zstream, Z_SYNC_FLUSH) != Z_OK) {
    113         fprintf(stderr, "VNC: error during zlib compression\n");
    114         return -1;
    115     }
    116 
    117     vs->output.offset = vs->output.capacity - zstream->avail_out;
    118     return previous_out - zstream->avail_out;
    119 }
    120 
    121 int vnc_zlib_send_framebuffer_update(VncState *vs, int x, int y, int w, int h)
    122 {
    123     int old_offset, new_offset, bytes_written;
    124 
    125     vnc_framebuffer_update(vs, x, y, w, h, VNC_ENCODING_ZLIB);
    126 
    127     // remember where we put in the follow-up size
    128     old_offset = vs->output.offset;
    129     vnc_write_s32(vs, 0);
    130 
    131     // compress the stream
    132     vnc_zlib_start(vs);
    133     vnc_raw_send_framebuffer_update(vs, x, y, w, h);
    134     bytes_written = vnc_zlib_stop(vs);
    135 
    136     if (bytes_written == -1)
    137         return 0;
    138 
    139     // hack in the size
    140     new_offset = vs->output.offset;
    141     vs->output.offset = old_offset;
    142     vnc_write_u32(vs, bytes_written);
    143     vs->output.offset = new_offset;
    144 
    145     return 1;
    146 }
    147 
    148 void vnc_zlib_clear(VncState *vs)
    149 {
    150     if (vs->zlib.stream.opaque) {
    151         deflateEnd(&vs->zlib.stream);
    152     }
    153     buffer_free(&vs->zlib.zlib);
    154 }