Bug Summary

File:ui/vnc-enc-zrle.c
Location:line 165, column 17
Description:Value stored to 'estimated_bytes' is never read

Annotated Source Code

1/*
2 * QEMU VNC display driver: Zlib Run-length Encoding (ZRLE)
3 *
4 * From libvncserver/libvncserver/zrle.c
5 * Copyright (C) 2002 RealVNC Ltd. All Rights Reserved.
6 * Copyright (C) 2003 Sun Microsystems, Inc.
7 *
8 * Copyright (C) 2010 Corentin Chary <corentin.chary@gmail.com>
9 *
10 * Permission is hereby granted, free of charge, to any person obtaining a copy
11 * of this software and associated documentation files (the "Software"), to deal
12 * in the Software without restriction, including without limitation the rights
13 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
14 * copies of the Software, and to permit persons to whom the Software is
15 * furnished to do so, subject to the following conditions:
16 *
17 * The above copyright notice and this permission notice shall be included in
18 * all copies or substantial portions of the Software.
19 *
20 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
21 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
23 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
24 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
25 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
26 * THE SOFTWARE.
27 */
28
29#include "vnc.h"
30#include "vnc-enc-zrle.h"
31
32static const int bits_per_packed_pixel[] = {
33 0, 1, 2, 2, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4
34};
35
36
37static void vnc_zrle_start(VncState *vs)
38{
39 buffer_reset(&vs->zrle.zrle);
40
41 /* make the output buffer be the zlib buffer, so we can compress it later */
42 vs->zrle.tmp = vs->output;
43 vs->output = vs->zrle.zrle;
44}
45
46static void vnc_zrle_stop(VncState *vs)
47{
48 /* switch back to normal output/zlib buffers */
49 vs->zrle.zrle = vs->output;
50 vs->output = vs->zrle.tmp;
51}
52
53static void *zrle_convert_fb(VncState *vs, int x, int y, int w, int h,
54 int bpp)
55{
56 Buffer tmp;
57
58 buffer_reset(&vs->zrle.fb);
59 buffer_reserve(&vs->zrle.fb, w * h * bpp + bpp);
60
61 tmp = vs->output;
62 vs->output = vs->zrle.fb;
63
64 vnc_raw_send_framebuffer_update(vs, x, y, w, h);
65
66 vs->zrle.fb = vs->output;
67 vs->output = tmp;
68 return vs->zrle.fb.buffer;
69}
70
71static int zrle_compress_data(VncState *vs, int level)
72{
73 z_streamp zstream = &vs->zrle.stream;
74
75 buffer_reset(&vs->zrle.zlib);
76
77 if (zstream->opaque != vs) {
78 int err;
79
80 zstream->zalloc = vnc_zlib_zalloc;
81 zstream->zfree = vnc_zlib_zfree;
82
83 err = deflateInit2(zstream, level, Z_DEFLATED, MAX_WBITS,deflateInit2_((zstream),(level),(8),(15),(9), (0), "1.2.3.4",
sizeof(z_stream))
84 MAX_MEM_LEVEL, Z_DEFAULT_STRATEGY)deflateInit2_((zstream),(level),(8),(15),(9), (0), "1.2.3.4",
sizeof(z_stream));
85
86 if (err != Z_OK0) {
87 fprintf(stderrstderr, "VNC: error initializing zlib\n");
88 return -1;
89 }
90
91 zstream->opaque = vs;
92 }
93
94 /* reserve memory in output buffer */
95 buffer_reserve(&vs->zrle.zlib, vs->zrle.zrle.offset + 64);
96
97 /* set pointers */
98 zstream->next_in = vs->zrle.zrle.buffer;
99 zstream->avail_in = vs->zrle.zrle.offset;
100 zstream->next_out = vs->zrle.zlib.buffer + vs->zrle.zlib.offset;
101 zstream->avail_out = vs->zrle.zlib.capacity - vs->zrle.zlib.offset;
102 zstream->data_type = Z_BINARY0;
103
104 /* start encoding */
105 if (deflate(zstream, Z_SYNC_FLUSH2) != Z_OK0) {
106 fprintf(stderrstderr, "VNC: error during zrle compression\n");
107 return -1;
108 }
109
110 vs->zrle.zlib.offset = vs->zrle.zlib.capacity - zstream->avail_out;
111 return vs->zrle.zlib.offset;
112}
113
114/* Try to work out whether to use RLE and/or a palette. We do this by
115 * estimating the number of bytes which will be generated and picking the
116 * method which results in the fewest bytes. Of course this may not result
117 * in the fewest bytes after compression... */
118static void zrle_choose_palette_rle(VncState *vs, int w, int h,
119 VncPalette *palette, int bpp_out,
120 int runs, int single_pixels,
121 int zywrle_level,
122 bool_Bool *use_rle, bool_Bool *use_palette)
123{
124 size_t estimated_bytes;
125 size_t plain_rle_bytes;
126
127 *use_palette = *use_rle = false0;
128
129 estimated_bytes = w * h * (bpp_out / 8); /* start assuming raw */
130
131 if (bpp_out != 8) {
132 if (zywrle_level > 0 && !(zywrle_level & 0x80))
133 estimated_bytes >>= zywrle_level;
134 }
135
136 plain_rle_bytes = ((bpp_out / 8) + 1) * (runs + single_pixels);
137
138 if (plain_rle_bytes < estimated_bytes) {
139 *use_rle = true1;
140 estimated_bytes = plain_rle_bytes;
141 }
142
143 if (palette_size(palette) < 128) {
144 int palette_rle_bytes;
145
146 palette_rle_bytes = (bpp_out / 8) * palette_size(palette);
147 palette_rle_bytes += 2 * runs + single_pixels;
148
149 if (palette_rle_bytes < estimated_bytes) {
150 *use_rle = true1;
151 *use_palette = true1;
152 estimated_bytes = palette_rle_bytes;
153 }
154
155 if (palette_size(palette) < 17) {
156 int packed_bytes;
157
158 packed_bytes = (bpp_out / 8) * palette_size(palette);
159 packed_bytes += w * h *
160 bits_per_packed_pixel[palette_size(palette)-1] / 8;
161
162 if (packed_bytes < estimated_bytes) {
163 *use_rle = false0;
164 *use_palette = true1;
165 estimated_bytes = packed_bytes;
Value stored to 'estimated_bytes' is never read
166 }
167 }
168 }
169}
170
171static void zrle_write_u32(VncState *vs, uint32_t value)
172{
173 vnc_write(vs, (uint8_t *)&value, 4);
174}
175
176static void zrle_write_u24a(VncState *vs, uint32_t value)
177{
178 vnc_write(vs, (uint8_t *)&value, 3);
179}
180
181static void zrle_write_u24b(VncState *vs, uint32_t value)
182{
183 vnc_write(vs, ((uint8_t *)&value) + 1, 3);
184}
185
186static void zrle_write_u16(VncState *vs, uint16_t value)
187{
188 vnc_write(vs, (uint8_t *)&value, 2);
189}
190
191static void zrle_write_u8(VncState *vs, uint8_t value)
192{
193 vnc_write_u8(vs, value);
194}
195
196#define ENDIAN_LITTLE0 0
197#define ENDIAN_BIG1 1
198#define ENDIAN_NO2 2
199
200#define ZRLE_BPP 8
201#define ZYWRLE_ENDIAN1 ENDIAN_NO2
202#include "vnc-enc-zrle-template.c"
203#undef ZRLE_BPP
204
205#define ZRLE_BPP 15
206#undef ZYWRLE_ENDIAN1
207#define ZYWRLE_ENDIAN1 ENDIAN_LITTLE0
208#include "vnc-enc-zrle-template.c"
209
210#undef ZYWRLE_ENDIAN1
211#define ZYWRLE_ENDIAN1 ENDIAN_BIG1
212#include "vnc-enc-zrle-template.c"
213
214#undef ZRLE_BPP
215#define ZRLE_BPP 16
216#undef ZYWRLE_ENDIAN1
217#define ZYWRLE_ENDIAN1 ENDIAN_LITTLE0
218#include "vnc-enc-zrle-template.c"
219
220#undef ZYWRLE_ENDIAN1
221#define ZYWRLE_ENDIAN1 ENDIAN_BIG1
222#include "vnc-enc-zrle-template.c"
223
224#undef ZRLE_BPP
225#define ZRLE_BPP 32
226#undef ZYWRLE_ENDIAN1
227#define ZYWRLE_ENDIAN1 ENDIAN_LITTLE0
228#include "vnc-enc-zrle-template.c"
229
230#undef ZYWRLE_ENDIAN1
231#define ZYWRLE_ENDIAN1 ENDIAN_BIG1
232#include "vnc-enc-zrle-template.c"
233
234#define ZRLE_COMPACT_PIXEL 24a
235#undef ZYWRLE_ENDIAN1
236#define ZYWRLE_ENDIAN1 ENDIAN_LITTLE0
237#include "vnc-enc-zrle-template.c"
238
239#undef ZYWRLE_ENDIAN1
240#define ZYWRLE_ENDIAN1 ENDIAN_BIG1
241#include "vnc-enc-zrle-template.c"
242
243#undef ZRLE_COMPACT_PIXEL
244#define ZRLE_COMPACT_PIXEL 24b
245#undef ZYWRLE_ENDIAN1
246#define ZYWRLE_ENDIAN1 ENDIAN_LITTLE0
247#include "vnc-enc-zrle-template.c"
248
249#undef ZYWRLE_ENDIAN1
250#define ZYWRLE_ENDIAN1 ENDIAN_BIG1
251#include "vnc-enc-zrle-template.c"
252#undef ZRLE_COMPACT_PIXEL
253#undef ZRLE_BPP
254
255static int zrle_send_framebuffer_update(VncState *vs, int x, int y,
256 int w, int h)
257{
258 bool_Bool be = !!(vs->clientds.flags & QEMU_BIG_ENDIAN_FLAG0x01);
259 size_t bytes;
260 int zywrle_level;
261
262 if (vs->zrle.type == VNC_ENCODING_ZYWRLE0x00000011) {
263 if (!vs->vd->lossy || vs->tight.quality == (uint8_t)-1
264 || vs->tight.quality == 9) {
265 zywrle_level = 0;
266 vs->zrle.type = VNC_ENCODING_ZRLE0x00000010;
267 } else if (vs->tight.quality < 3) {
268 zywrle_level = 3;
269 } else if (vs->tight.quality < 6) {
270 zywrle_level = 2;
271 } else {
272 zywrle_level = 1;
273 }
274 } else {
275 zywrle_level = 0;
276 }
277
278 vnc_zrle_start(vs);
279
280 switch(vs->clientds.pf.bytes_per_pixel) {
281 case 1:
282 zrle_encode_8ne(vs, x, y, w, h, zywrle_level);
283 break;
284
285 case 2:
286 if (vs->clientds.pf.gmax > 0x1F) {
287 if (be) {
288 zrle_encode_16be(vs, x, y, w, h, zywrle_level);
289 } else {
290 zrle_encode_16le(vs, x, y, w, h, zywrle_level);
291 }
292 } else {
293 if (be) {
294 zrle_encode_15be(vs, x, y, w, h, zywrle_level);
295 } else {
296 zrle_encode_15le(vs, x, y, w, h, zywrle_level);
297 }
298 }
299 break;
300
301 case 4:
302 {
303 bool_Bool fits_in_ls3bytes;
304 bool_Bool fits_in_ms3bytes;
305
306 fits_in_ls3bytes =
307 ((vs->clientds.pf.rmax << vs->clientds.pf.rshift) < (1 << 24) &&
308 (vs->clientds.pf.gmax << vs->clientds.pf.gshift) < (1 << 24) &&
309 (vs->clientds.pf.bmax << vs->clientds.pf.bshift) < (1 << 24));
310
311 fits_in_ms3bytes = (vs->clientds.pf.rshift > 7 &&
312 vs->clientds.pf.gshift > 7 &&
313 vs->clientds.pf.bshift > 7);
314
315 if ((fits_in_ls3bytes && !be) || (fits_in_ms3bytes && be)) {
316 if (be) {
317 zrle_encode_24abe(vs, x, y, w, h, zywrle_level);
318 } else {
319 zrle_encode_24ale(vs, x, y, w, h, zywrle_level);
320 }
321 } else if ((fits_in_ls3bytes && be) || (fits_in_ms3bytes && !be)) {
322 if (be) {
323 zrle_encode_24bbe(vs, x, y, w, h, zywrle_level);
324 } else {
325 zrle_encode_24ble(vs, x, y, w, h, zywrle_level);
326 }
327 } else {
328 if (be) {
329 zrle_encode_32be(vs, x, y, w, h, zywrle_level);
330 } else {
331 zrle_encode_32le(vs, x, y, w, h, zywrle_level);
332 }
333 }
334 }
335 break;
336 }
337
338 vnc_zrle_stop(vs);
339 bytes = zrle_compress_data(vs, Z_DEFAULT_COMPRESSION(-1));
340 vnc_framebuffer_update(vs, x, y, w, h, vs->zrle.type);
341 vnc_write_u32(vs, bytes);
342 vnc_write(vs, vs->zrle.zlib.buffer, vs->zrle.zlib.offset);
343 return 1;
344}
345
346int vnc_zrle_send_framebuffer_update(VncState *vs, int x, int y, int w, int h)
347{
348 vs->zrle.type = VNC_ENCODING_ZRLE0x00000010;
349 return zrle_send_framebuffer_update(vs, x, y, w, h);
350}
351
352int vnc_zywrle_send_framebuffer_update(VncState *vs, int x, int y, int w, int h)
353{
354 vs->zrle.type = VNC_ENCODING_ZYWRLE0x00000011;
355 return zrle_send_framebuffer_update(vs, x, y, w, h);
356}
357
358void vnc_zrle_clear(VncState *vs)
359{
360 if (vs->zrle.stream.opaque) {
361 deflateEnd(&vs->zrle.stream);
362 }
363 buffer_free(&vs->zrle.zrle);
364 buffer_free(&vs->zrle.fb);
365 buffer_free(&vs->zrle.zlib);
366}