Bug Summary

File:pixman/pixman-trap.c
Location:line 371, column 5
Description:Value stored to 'x_off_fixed' is never read

Annotated Source Code

1/*
2 * Copyright © 2004 Keith Packard
3 *
4 * Permission to use, copy, modify, distribute, and sell this software and its
5 * documentation for any purpose is hereby granted without fee, provided that
6 * the above copyright notice appear in all copies and that both that
7 * copyright notice and this permission notice appear in supporting
8 * documentation, and that the name of Keith Packard not be used in
9 * advertising or publicity pertaining to distribution of the software without
10 * specific, written prior permission. Keith Packard makes no
11 * representations about the suitability of this software for any purpose. It
12 * is provided "as is" without express or implied warranty.
13 *
14 * KEITH PACKARD DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
15 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
16 * EVENT SHALL KEITH PACKARD BE LIABLE FOR ANY SPECIAL, INDIRECT OR
17 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
18 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
19 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
20 * PERFORMANCE OF THIS SOFTWARE.
21 */
22
23#ifdef HAVE_CONFIG_H1
24#include <config.h>
25#endif
26
27#include <stdio.h>
28#include "pixman-private.h"
29
30/*
31 * Compute the smallest value greater than or equal to y which is on a
32 * grid row.
33 */
34
35PIXMAN_EXPORT__attribute__ ((visibility("default"))) pixman_fixed_t
36pixman_sample_ceil_y (pixman_fixed_t y, int n)
37{
38 pixman_fixed_t f = pixman_fixed_frac (y)((y) & ((((pixman_fixed_t) ((1) << 16))) - ((pixman_fixed_t
) 1)));
39 pixman_fixed_t i = pixman_fixed_floor (y)((y) & ~((((pixman_fixed_t) ((1) << 16))) - ((pixman_fixed_t
) 1)));
40
41 f = DIV (f - Y_FRAC_FIRST (n) + (STEP_Y_SMALL (n) - pixman_fixed_e), STEP_Y_SMALL (n))((((f - (((((pixman_fixed_t) ((1) << 16))) - (((n) == 1
? 1 : (1 << ((n) / 2)) - 1) - 1) * ((((pixman_fixed_t)
((1) << 16))) / ((n) == 1 ? 1 : (1 << ((n) / 2))
- 1))) / 2) + (((((pixman_fixed_t) ((1) << 16))) / ((n
) == 1 ? 1 : (1 << ((n) / 2)) - 1)) - ((pixman_fixed_t)
1))) < 0) == ((((((pixman_fixed_t) ((1) << 16))) / (
(n) == 1 ? 1 : (1 << ((n) / 2)) - 1))) < 0)) ? (f - (
((((pixman_fixed_t) ((1) << 16))) - (((n) == 1 ? 1 : (1
<< ((n) / 2)) - 1) - 1) * ((((pixman_fixed_t) ((1) <<
16))) / ((n) == 1 ? 1 : (1 << ((n) / 2)) - 1))) / 2) +
(((((pixman_fixed_t) ((1) << 16))) / ((n) == 1 ? 1 : (
1 << ((n) / 2)) - 1)) - ((pixman_fixed_t) 1))) / (((((pixman_fixed_t
) ((1) << 16))) / ((n) == 1 ? 1 : (1 << ((n) / 2)
) - 1))) : ((f - (((((pixman_fixed_t) ((1) << 16))) - (
((n) == 1 ? 1 : (1 << ((n) / 2)) - 1) - 1) * ((((pixman_fixed_t
) ((1) << 16))) / ((n) == 1 ? 1 : (1 << ((n) / 2)
) - 1))) / 2) + (((((pixman_fixed_t) ((1) << 16))) / ((
n) == 1 ? 1 : (1 << ((n) / 2)) - 1)) - ((pixman_fixed_t
) 1))) - (((((pixman_fixed_t) ((1) << 16))) / ((n) == 1
? 1 : (1 << ((n) / 2)) - 1))) + 1 - (((((((pixman_fixed_t
) ((1) << 16))) / ((n) == 1 ? 1 : (1 << ((n) / 2)
) - 1))) < 0) << 1)) / (((((pixman_fixed_t) ((1) <<
16))) / ((n) == 1 ? 1 : (1 << ((n) / 2)) - 1)))) * STEP_Y_SMALL (n)((((pixman_fixed_t) ((1) << 16))) / ((n) == 1 ? 1 : (1 <<
((n) / 2)) - 1)) +
42 Y_FRAC_FIRST (n)(((((pixman_fixed_t) ((1) << 16))) - (((n) == 1 ? 1 : (
1 << ((n) / 2)) - 1) - 1) * ((((pixman_fixed_t) ((1) <<
16))) / ((n) == 1 ? 1 : (1 << ((n) / 2)) - 1))) / 2);
43
44 if (f > Y_FRAC_LAST (n)((((((pixman_fixed_t) ((1) << 16))) - (((n) == 1 ? 1 : (
1 << ((n) / 2)) - 1) - 1) * ((((pixman_fixed_t) ((1) <<
16))) / ((n) == 1 ? 1 : (1 << ((n) / 2)) - 1))) / 2) +
(((n) == 1 ? 1 : (1 << ((n) / 2)) - 1) - 1) * ((((pixman_fixed_t
) ((1) << 16))) / ((n) == 1 ? 1 : (1 << ((n) / 2)
) - 1))))
45 {
46 if (pixman_fixed_to_int (i)((int) ((i) >> 16)) == 0x7fff)
47 {
48 f = 0xffff; /* saturate */
49 }
50 else
51 {
52 f = Y_FRAC_FIRST (n)(((((pixman_fixed_t) ((1) << 16))) - (((n) == 1 ? 1 : (
1 << ((n) / 2)) - 1) - 1) * ((((pixman_fixed_t) ((1) <<
16))) / ((n) == 1 ? 1 : (1 << ((n) / 2)) - 1))) / 2);
53 i += pixman_fixed_1(((pixman_fixed_t) ((1) << 16)));
54 }
55 }
56 return (i | f);
57}
58
59/*
60 * Compute the largest value strictly less than y which is on a
61 * grid row.
62 */
63PIXMAN_EXPORT__attribute__ ((visibility("default"))) pixman_fixed_t
64pixman_sample_floor_y (pixman_fixed_t y,
65 int n)
66{
67 pixman_fixed_t f = pixman_fixed_frac (y)((y) & ((((pixman_fixed_t) ((1) << 16))) - ((pixman_fixed_t
) 1)));
68 pixman_fixed_t i = pixman_fixed_floor (y)((y) & ~((((pixman_fixed_t) ((1) << 16))) - ((pixman_fixed_t
) 1)));
69
70 f = DIV (f - pixman_fixed_e - Y_FRAC_FIRST (n), STEP_Y_SMALL (n))((((f - ((pixman_fixed_t) 1) - (((((pixman_fixed_t) ((1) <<
16))) - (((n) == 1 ? 1 : (1 << ((n) / 2)) - 1) - 1) * (
(((pixman_fixed_t) ((1) << 16))) / ((n) == 1 ? 1 : (1 <<
((n) / 2)) - 1))) / 2)) < 0) == ((((((pixman_fixed_t) ((1
) << 16))) / ((n) == 1 ? 1 : (1 << ((n) / 2)) - 1
))) < 0)) ? (f - ((pixman_fixed_t) 1) - (((((pixman_fixed_t
) ((1) << 16))) - (((n) == 1 ? 1 : (1 << ((n) / 2
)) - 1) - 1) * ((((pixman_fixed_t) ((1) << 16))) / ((n)
== 1 ? 1 : (1 << ((n) / 2)) - 1))) / 2)) / (((((pixman_fixed_t
) ((1) << 16))) / ((n) == 1 ? 1 : (1 << ((n) / 2)
) - 1))) : ((f - ((pixman_fixed_t) 1) - (((((pixman_fixed_t) (
(1) << 16))) - (((n) == 1 ? 1 : (1 << ((n) / 2)) -
1) - 1) * ((((pixman_fixed_t) ((1) << 16))) / ((n) == 1
? 1 : (1 << ((n) / 2)) - 1))) / 2)) - (((((pixman_fixed_t
) ((1) << 16))) / ((n) == 1 ? 1 : (1 << ((n) / 2)
) - 1))) + 1 - (((((((pixman_fixed_t) ((1) << 16))) / (
(n) == 1 ? 1 : (1 << ((n) / 2)) - 1))) < 0) <<
1)) / (((((pixman_fixed_t) ((1) << 16))) / ((n) == 1 ?
1 : (1 << ((n) / 2)) - 1)))) * STEP_Y_SMALL (n)((((pixman_fixed_t) ((1) << 16))) / ((n) == 1 ? 1 : (1 <<
((n) / 2)) - 1)) +
71 Y_FRAC_FIRST (n)(((((pixman_fixed_t) ((1) << 16))) - (((n) == 1 ? 1 : (
1 << ((n) / 2)) - 1) - 1) * ((((pixman_fixed_t) ((1) <<
16))) / ((n) == 1 ? 1 : (1 << ((n) / 2)) - 1))) / 2);
72
73 if (f < Y_FRAC_FIRST (n)(((((pixman_fixed_t) ((1) << 16))) - (((n) == 1 ? 1 : (
1 << ((n) / 2)) - 1) - 1) * ((((pixman_fixed_t) ((1) <<
16))) / ((n) == 1 ? 1 : (1 << ((n) / 2)) - 1))) / 2))
74 {
75 if (pixman_fixed_to_int (i)((int) ((i) >> 16)) == 0x8000)
76 {
77 f = 0; /* saturate */
78 }
79 else
80 {
81 f = Y_FRAC_LAST (n)((((((pixman_fixed_t) ((1) << 16))) - (((n) == 1 ? 1 : (
1 << ((n) / 2)) - 1) - 1) * ((((pixman_fixed_t) ((1) <<
16))) / ((n) == 1 ? 1 : (1 << ((n) / 2)) - 1))) / 2) +
(((n) == 1 ? 1 : (1 << ((n) / 2)) - 1) - 1) * ((((pixman_fixed_t
) ((1) << 16))) / ((n) == 1 ? 1 : (1 << ((n) / 2)
) - 1)));
82 i -= pixman_fixed_1(((pixman_fixed_t) ((1) << 16)));
83 }
84 }
85 return (i | f);
86}
87
88/*
89 * Step an edge by any amount (including negative values)
90 */
91PIXMAN_EXPORT__attribute__ ((visibility("default"))) void
92pixman_edge_step (pixman_edge_t *e,
93 int n)
94{
95 pixman_fixed_48_16_t ne;
96
97 e->x += n * e->stepx;
98
99 ne = e->e + n * (pixman_fixed_48_16_t) e->dx;
100
101 if (n >= 0)
102 {
103 if (ne > 0)
104 {
105 int nx = (ne + e->dy - 1) / e->dy;
106 e->e = ne - nx * (pixman_fixed_48_16_t) e->dy;
107 e->x += nx * e->signdx;
108 }
109 }
110 else
111 {
112 if (ne <= -e->dy)
113 {
114 int nx = (-ne) / e->dy;
115 e->e = ne + nx * (pixman_fixed_48_16_t) e->dy;
116 e->x -= nx * e->signdx;
117 }
118 }
119}
120
121/*
122 * A private routine to initialize the multi-step
123 * elements of an edge structure
124 */
125static void
126_pixman_edge_multi_init (pixman_edge_t * e,
127 int n,
128 pixman_fixed_t *stepx_p,
129 pixman_fixed_t *dx_p)
130{
131 pixman_fixed_t stepx;
132 pixman_fixed_48_16_t ne;
133
134 ne = n * (pixman_fixed_48_16_t) e->dx;
135 stepx = n * e->stepx;
136
137 if (ne > 0)
138 {
139 int nx = ne / e->dy;
140 ne -= nx * e->dy;
141 stepx += nx * e->signdx;
142 }
143
144 *dx_p = ne;
145 *stepx_p = stepx;
146}
147
148/*
149 * Initialize one edge structure given the line endpoints and a
150 * starting y value
151 */
152PIXMAN_EXPORT__attribute__ ((visibility("default"))) void
153pixman_edge_init (pixman_edge_t *e,
154 int n,
155 pixman_fixed_t y_start,
156 pixman_fixed_t x_top,
157 pixman_fixed_t y_top,
158 pixman_fixed_t x_bot,
159 pixman_fixed_t y_bot)
160{
161 pixman_fixed_t dx, dy;
162
163 e->x = x_top;
164 e->e = 0;
165 dx = x_bot - x_top;
166 dy = y_bot - y_top;
167 e->dy = dy;
168 e->dx = 0;
169
170 if (dy)
171 {
172 if (dx >= 0)
173 {
174 e->signdx = 1;
175 e->stepx = dx / dy;
176 e->dx = dx % dy;
177 e->e = -dy;
178 }
179 else
180 {
181 e->signdx = -1;
182 e->stepx = -(-dx / dy);
183 e->dx = -dx % dy;
184 e->e = 0;
185 }
186
187 _pixman_edge_multi_init (e, STEP_Y_SMALL (n)((((pixman_fixed_t) ((1) << 16))) / ((n) == 1 ? 1 : (1 <<
((n) / 2)) - 1)),
188 &e->stepx_small, &e->dx_small);
189
190 _pixman_edge_multi_init (e, STEP_Y_BIG (n)((((pixman_fixed_t) ((1) << 16))) - (((n) == 1 ? 1 : (1
<< ((n) / 2)) - 1) - 1) * ((((pixman_fixed_t) ((1) <<
16))) / ((n) == 1 ? 1 : (1 << ((n) / 2)) - 1))),
191 &e->stepx_big, &e->dx_big);
192 }
193 pixman_edge_step (e, y_start - y_top);
194}
195
196/*
197 * Initialize one edge structure given a line, starting y value
198 * and a pixel offset for the line
199 */
200PIXMAN_EXPORT__attribute__ ((visibility("default"))) void
201pixman_line_fixed_edge_init (pixman_edge_t * e,
202 int n,
203 pixman_fixed_t y,
204 const pixman_line_fixed_t *line,
205 int x_off,
206 int y_off)
207{
208 pixman_fixed_t x_off_fixed = pixman_int_to_fixed (x_off)((pixman_fixed_t) ((x_off) << 16));
209 pixman_fixed_t y_off_fixed = pixman_int_to_fixed (y_off)((pixman_fixed_t) ((y_off) << 16));
210 const pixman_point_fixed_t *top, *bot;
211
212 if (line->p1.y <= line->p2.y)
213 {
214 top = &line->p1;
215 bot = &line->p2;
216 }
217 else
218 {
219 top = &line->p2;
220 bot = &line->p1;
221 }
222
223 pixman_edge_init (e, n, y,
224 top->x + x_off_fixed,
225 top->y + y_off_fixed,
226 bot->x + x_off_fixed,
227 bot->y + y_off_fixed);
228}
229
230PIXMAN_EXPORT__attribute__ ((visibility("default"))) void
231pixman_add_traps (pixman_image_t * image,
232 int16_t x_off,
233 int16_t y_off,
234 int ntrap,
235 pixman_trap_t * traps)
236{
237 int bpp;
238 int width;
239 int height;
240
241 pixman_fixed_t x_off_fixed;
242 pixman_fixed_t y_off_fixed;
243 pixman_edge_t l, r;
244 pixman_fixed_t t, b;
245
246 _pixman_image_validate (image);
247
248 width = image->bits.width;
249 height = image->bits.height;
250 bpp = PIXMAN_FORMAT_BPP (image->bits.format)(((image->bits.format) >> 24) );
251
252 x_off_fixed = pixman_int_to_fixed (x_off)((pixman_fixed_t) ((x_off) << 16));
253 y_off_fixed = pixman_int_to_fixed (y_off)((pixman_fixed_t) ((y_off) << 16));
254
255 while (ntrap--)
256 {
257 t = traps->top.y + y_off_fixed;
258 if (t < 0)
259 t = 0;
260 t = pixman_sample_ceil_y (t, bpp);
261
262 b = traps->bot.y + y_off_fixed;
263 if (pixman_fixed_to_int (b)((int) ((b) >> 16)) >= height)
264 b = pixman_int_to_fixed (height)((pixman_fixed_t) ((height) << 16)) - 1;
265 b = pixman_sample_floor_y (b, bpp);
266
267 if (b >= t)
268 {
269 /* initialize edge walkers */
270 pixman_edge_init (&l, bpp, t,
271 traps->top.l + x_off_fixed,
272 traps->top.y + y_off_fixed,
273 traps->bot.l + x_off_fixed,
274 traps->bot.y + y_off_fixed);
275
276 pixman_edge_init (&r, bpp, t,
277 traps->top.r + x_off_fixed,
278 traps->top.y + y_off_fixed,
279 traps->bot.r + x_off_fixed,
280 traps->bot.y + y_off_fixed);
281
282 pixman_rasterize_edges (image, &l, &r, t, b);
283 }
284
285 traps++;
286 }
287}
288
289#if 0
290static void
291dump_image (pixman_image_t *image,
292 const char * title)
293{
294 int i, j;
295
296 if (!image->type == BITS)
297 printf ("%s is not a regular image\n", title);
298
299 if (!image->bits.format == PIXMAN_a8)
300 printf ("%s is not an alpha mask\n", title);
301
302 printf ("\n\n\n%s: \n", title);
303
304 for (i = 0; i < image->bits.height; ++i)
305 {
306 uint8_t *line =
307 (uint8_t *)&(image->bits.bits[i * image->bits.rowstride]);
308
309 for (j = 0; j < image->bits.width; ++j)
310 printf ("%c", line[j] ? '#' : ' ');
311
312 printf ("\n");
313 }
314}
315#endif
316
317PIXMAN_EXPORT__attribute__ ((visibility("default"))) void
318pixman_add_trapezoids (pixman_image_t * image,
319 int16_t x_off,
320 int y_off,
321 int ntraps,
322 const pixman_trapezoid_t *traps)
323{
324 int i;
325
326#if 0
327 dump_image (image, "before");
328#endif
329
330 for (i = 0; i < ntraps; ++i)
331 {
332 const pixman_trapezoid_t *trap = &(traps[i]);
333
334 if (!pixman_trapezoid_valid (trap)((trap)->left.p1.y != (trap)->left.p2.y && (trap
)->right.p1.y != (trap)->right.p2.y && (int) ((
trap)->bottom - (trap)->top) > 0))
335 continue;
336
337 pixman_rasterize_trapezoid (image, trap, x_off, y_off);
338 }
339
340#if 0
341 dump_image (image, "after");
342#endif
343}
344
345PIXMAN_EXPORT__attribute__ ((visibility("default"))) void
346pixman_rasterize_trapezoid (pixman_image_t * image,
347 const pixman_trapezoid_t *trap,
348 int x_off,
349 int y_off)
350{
351 int bpp;
352 int width;
353 int height;
354
355 pixman_fixed_t x_off_fixed;
356 pixman_fixed_t y_off_fixed;
357 pixman_edge_t l, r;
358 pixman_fixed_t t, b;
359
360 return_if_fail (image->type == BITS)do { if (!(image->type == BITS)) { _pixman_log_error (((const
char*) (__PRETTY_FUNCTION__)), "The expression " "image->type == BITS"
" was false"); return; } } while (0);
361
362 _pixman_image_validate (image);
363
364 if (!pixman_trapezoid_valid (trap)((trap)->left.p1.y != (trap)->left.p2.y && (trap
)->right.p1.y != (trap)->right.p2.y && (int) ((
trap)->bottom - (trap)->top) > 0))
365 return;
366
367 width = image->bits.width;
368 height = image->bits.height;
369 bpp = PIXMAN_FORMAT_BPP (image->bits.format)(((image->bits.format) >> 24) );
370
371 x_off_fixed = pixman_int_to_fixed (x_off)((pixman_fixed_t) ((x_off) << 16));
Value stored to 'x_off_fixed' is never read
372 y_off_fixed = pixman_int_to_fixed (y_off)((pixman_fixed_t) ((y_off) << 16));
373
374 t = trap->top + y_off_fixed;
375 if (t < 0)
376 t = 0;
377 t = pixman_sample_ceil_y (t, bpp);
378
379 b = trap->bottom + y_off_fixed;
380 if (pixman_fixed_to_int (b)((int) ((b) >> 16)) >= height)
381 b = pixman_int_to_fixed (height)((pixman_fixed_t) ((height) << 16)) - 1;
382 b = pixman_sample_floor_y (b, bpp);
383
384 if (b >= t)
385 {
386 /* initialize edge walkers */
387 pixman_line_fixed_edge_init (&l, bpp, t, &trap->left, x_off, y_off);
388 pixman_line_fixed_edge_init (&r, bpp, t, &trap->right, x_off, y_off);
389
390 pixman_rasterize_edges (image, &l, &r, t, b);
391 }
392}