xref: /openbmc/qemu/ui/vnc-enc-zlib.c (revision 764a6ee9)
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 }
155