ui/vnc-enc-zlib.c

   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 }