Bug Summary

File:root/firefox-clang/gfx/cairo/cairo/src/cairo-bentley-ottmann.c
Warning:line 825, column 1
1st function call argument is an uninitialized value

Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name cairo-bentley-ottmann.c -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -fhalf-no-semantic-interposition -mframe-pointer=all -relaxed-aliasing -ffp-contract=off -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -fdebug-compilation-dir=/root/firefox-clang/obj-x86_64-pc-linux-gnu/gfx/cairo/cairo/src -fcoverage-compilation-dir=/root/firefox-clang/obj-x86_64-pc-linux-gnu/gfx/cairo/cairo/src -resource-dir /usr/lib/llvm-21/lib/clang/21 -include /root/firefox-clang/config/gcc_hidden.h -include /root/firefox-clang/obj-x86_64-pc-linux-gnu/mozilla-config.h -I /root/firefox-clang/obj-x86_64-pc-linux-gnu/dist/system_wrappers -U _FORTIFY_SOURCE -D _FORTIFY_SOURCE=2 -D _GLIBCXX_ASSERTIONS -D DEBUG=1 -D HAVE_FT_LOAD_SFNT_TABLE -D PACKAGE_VERSION="moz" -D PACKAGE_BUGREPORT="http://bugzilla.mozilla.org/" -D CAIRO_HAS_PTHREAD -D _GNU_SOURCE -D MOZ_TREE_PIXMAN -D SIZEOF_VOID_P=__SIZEOF_POINTER__ -D SIZEOF_INT=__SIZEOF_INT__ -D SIZEOF_LONG=__SIZEOF_LONG__ -D SIZEOF_LONG_LONG=__SIZEOF_LONG_LONG__ -D HAVE_UINT64_T -D HAVE_CXX11_ATOMIC_PRIMITIVES -D MOZ_HAS_MOZGLUE -D MOZILLA_INTERNAL_API -D IMPL_LIBXUL -D MOZ_SUPPORT_LEAKCHECKING -D STATIC_EXPORTABLE_JS_API -I /root/firefox-clang/gfx/cairo/cairo/src -I /root/firefox-clang/obj-x86_64-pc-linux-gnu/gfx/cairo/cairo/src -I /root/firefox-clang/obj-x86_64-pc-linux-gnu/dist/include -I /root/firefox-clang/obj-x86_64-pc-linux-gnu/dist/include/nspr -I /root/firefox-clang/obj-x86_64-pc-linux-gnu/dist/include/nss -D MOZILLA_CLIENT -I /usr/include/freetype2 -I /usr/include/libpng16 -I /usr/include/freetype2 -I /usr/include/libpng16 -internal-isystem /usr/lib/llvm-21/lib/clang/21/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/14/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-error=tautological-type-limit-compare -Wno-range-loop-analysis -Wno-error=deprecated-declarations -Wno-error=array-bounds -Wno-error=free-nonheap-object -Wno-error=atomic-alignment -Wno-error=deprecated-builtins -Wno-psabi -Wno-error=builtin-macro-redefined -Wno-unknown-warning-option -Wno-enum-compare -Wno-int-to-pointer-cast -Wno-int-conversion -Wno-incompatible-pointer-types -Wno-sign-compare -Wno-type-limits -Wno-missing-field-initializers -Wno-conversion -Wno-narrowing -Wno-switch -Wno-unused -Wno-unused-variable -Wno-error=uninitialized -Wno-absolute-value -Wno-deprecated-register -Wno-incompatible-pointer-types -Wno-macro-redefined -Wno-shift-negative-value -Wno-tautological-compare -Wno-tautological-constant-out-of-range-compare -Wno-unreachable-code -ferror-limit 19 -fstrict-flex-arrays=1 -stack-protector 2 -fstack-clash-protection -ftrivial-auto-var-init=pattern -fgnuc-version=4.2.1 -fskip-odr-check-in-gmf -vectorize-loops -vectorize-slp -analyzer-checker optin.performance.Padding -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/scan-build-2025-06-26-231904-1820671-1 -x c /root/firefox-clang/gfx/cairo/cairo/src/cairo-bentley-ottmann.c
1/*
2 * Copyright © 2004 Carl Worth
3 * Copyright © 2006 Red Hat, Inc.
4 * Copyright © 2008 Chris Wilson
5 *
6 * This library is free software; you can redistribute it and/or
7 * modify it either under the terms of the GNU Lesser General Public
8 * License version 2.1 as published by the Free Software Foundation
9 * (the "LGPL") or, at your option, under the terms of the Mozilla
10 * Public License Version 1.1 (the "MPL"). If you do not alter this
11 * notice, a recipient may use your version of this file under either
12 * the MPL or the LGPL.
13 *
14 * You should have received a copy of the LGPL along with this library
15 * in the file COPYING-LGPL-2.1; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA
17 * You should have received a copy of the MPL along with this library
18 * in the file COPYING-MPL-1.1
19 *
20 * The contents of this file are subject to the Mozilla Public License
21 * Version 1.1 (the "License"); you may not use this file except in
22 * compliance with the License. You may obtain a copy of the License at
23 * http://www.mozilla.org/MPL/
24 *
25 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
26 * OF ANY KIND, either express or implied. See the LGPL or the MPL for
27 * the specific language governing rights and limitations.
28 *
29 * The Original Code is the cairo graphics library.
30 *
31 * The Initial Developer of the Original Code is Carl Worth
32 *
33 * Contributor(s):
34 * Carl D. Worth <cworth@cworth.org>
35 * Chris Wilson <chris@chris-wilson.co.uk>
36 */
37
38/* Provide definitions for standalone compilation */
39#include "cairoint.h"
40
41#include "cairo-combsort-inline.h"
42#include "cairo-error-private.h"
43#include "cairo-freelist-private.h"
44#include "cairo-line-inline.h"
45#include "cairo-traps-private.h"
46
47#define DEBUG_PRINT_STATE0 0
48#define DEBUG_EVENTS0 0
49#define DEBUG_TRAPS0 0
50
51typedef cairo_point_t cairo_bo_point32_t;
52
53typedef struct _cairo_bo_intersect_ordinate {
54 int32_t ordinate;
55 enum { EXACT, INEXACT } exactness;
56} cairo_bo_intersect_ordinate_t;
57
58typedef struct _cairo_bo_intersect_point {
59 cairo_bo_intersect_ordinate_t x;
60 cairo_bo_intersect_ordinate_t y;
61} cairo_bo_intersect_point_t;
62
63typedef struct _cairo_bo_edge cairo_bo_edge_t;
64typedef struct _cairo_bo_trap cairo_bo_trap_t;
65
66/* A deferred trapezoid of an edge */
67struct _cairo_bo_trap {
68 cairo_bo_edge_t *right;
69 int32_t top;
70};
71
72struct _cairo_bo_edge {
73 cairo_edge_t edge;
74 cairo_bo_edge_t *prev;
75 cairo_bo_edge_t *next;
76 cairo_bo_edge_t *colinear;
77 cairo_bo_trap_t deferred_trap;
78};
79
80/* the parent is always given by index/2 */
81#define PQ_PARENT_INDEX(i)((i) >> 1) ((i) >> 1)
82#define PQ_FIRST_ENTRY1 1
83
84/* left and right children are index * 2 and (index * 2) +1 respectively */
85#define PQ_LEFT_CHILD_INDEX(i)((i) << 1) ((i) << 1)
86
87typedef enum {
88 CAIRO_BO_EVENT_TYPE_STOP,
89 CAIRO_BO_EVENT_TYPE_INTERSECTION,
90 CAIRO_BO_EVENT_TYPE_START
91} cairo_bo_event_type_t;
92
93typedef struct _cairo_bo_event {
94 cairo_bo_event_type_t type;
95 cairo_point_t point;
96} cairo_bo_event_t;
97
98typedef struct _cairo_bo_start_event {
99 cairo_bo_event_type_t type;
100 cairo_point_t point;
101 cairo_bo_edge_t edge;
102} cairo_bo_start_event_t;
103
104typedef struct _cairo_bo_queue_event {
105 cairo_bo_event_type_t type;
106 cairo_point_t point;
107 cairo_bo_edge_t *e1;
108 cairo_bo_edge_t *e2;
109} cairo_bo_queue_event_t;
110
111typedef struct _pqueue {
112 int size, max_size;
113
114 cairo_bo_event_t **elements;
115 cairo_bo_event_t *elements_embedded[1024];
116} pqueue_t;
117
118typedef struct _cairo_bo_event_queue {
119 cairo_freepool_t pool;
120 pqueue_t pqueue;
121 cairo_bo_event_t **start_events;
122} cairo_bo_event_queue_t;
123
124typedef struct _cairo_bo_sweep_line {
125 cairo_bo_edge_t *head;
126 cairo_bo_edge_t *stopped;
127 int32_t current_y;
128 cairo_bo_edge_t *current_edge;
129} cairo_bo_sweep_line_t;
130
131#if DEBUG_TRAPS0
132static void
133dump_traps (cairo_traps_t *traps, const char *filename)
134{
135 FILE *file;
136 cairo_box_t extents;
137 int n;
138
139 if (getenv ("CAIRO_DEBUG_TRAPS") == NULL((void*)0))
140 return;
141
142#if 0
143 if (traps->has_limits) {
144 printf ("%s: limits=(%d, %d, %d, %d)\n",
145 filename,
146 traps->limits.p1.x, traps->limits.p1.y,
147 traps->limits.p2.x, traps->limits.p2.y);
148 }
149#endif
150 _cairo_traps_extents (traps, &extents);
151 printf ("%s: extents=(%d, %d, %d, %d)\n",
152 filename,
153 extents.p1.x, extents.p1.y,
154 extents.p2.x, extents.p2.y);
155
156 file = fopen (filename, "a");
157 if (file != NULL((void*)0)) {
158 for (n = 0; n < traps->num_traps; n++) {
159 fprintf (file, "%d %d L:(%d, %d), (%d, %d) R:(%d, %d), (%d, %d)\n",
160 traps->traps[n].top,
161 traps->traps[n].bottom,
162 traps->traps[n].left.p1.x,
163 traps->traps[n].left.p1.y,
164 traps->traps[n].left.p2.x,
165 traps->traps[n].left.p2.y,
166 traps->traps[n].right.p1.x,
167 traps->traps[n].right.p1.y,
168 traps->traps[n].right.p2.x,
169 traps->traps[n].right.p2.y);
170 }
171 fprintf (file, "\n");
172 fclose (file);
173 }
174}
175
176static void
177dump_edges (cairo_bo_start_event_t *events,
178 int num_edges,
179 const char *filename)
180{
181 FILE *file;
182 int n;
183
184 if (getenv ("CAIRO_DEBUG_TRAPS") == NULL((void*)0))
185 return;
186
187 file = fopen (filename, "a");
188 if (file != NULL((void*)0)) {
189 for (n = 0; n < num_edges; n++) {
190 fprintf (file, "(%d, %d), (%d, %d) %d %d %d\n",
191 events[n].edge.edge.line.p1.x,
192 events[n].edge.edge.line.p1.y,
193 events[n].edge.edge.line.p2.x,
194 events[n].edge.edge.line.p2.y,
195 events[n].edge.edge.top,
196 events[n].edge.edge.bottom,
197 events[n].edge.edge.dir);
198 }
199 fprintf (file, "\n");
200 fclose (file);
201 }
202}
203#endif
204
205static cairo_fixed_t
206_line_compute_intersection_x_for_y (const cairo_line_t *line,
207 cairo_fixed_t y)
208{
209 cairo_fixed_t x, dy;
210
211 if (y == line->p1.y)
212 return line->p1.x;
213 if (y == line->p2.y)
214 return line->p2.x;
215
216 x = line->p1.x;
217 dy = line->p2.y - line->p1.y;
218 if (dy != 0) {
219 x += _cairo_fixed_mul_div_floor (y - line->p1.y,
220 line->p2.x - line->p1.x,
221 dy);
222 }
223
224 return x;
225}
226
227static inline int
228_cairo_bo_point32_compare (cairo_bo_point32_t const *a,
229 cairo_bo_point32_t const *b)
230{
231 int cmp;
232
233 cmp = a->y - b->y;
234 if (cmp)
235 return cmp;
236
237 return a->x - b->x;
238}
239
240/* Compare the slope of a to the slope of b, returning 1, 0, -1 if the
241 * slope a is respectively greater than, equal to, or less than the
242 * slope of b.
243 *
244 * For each edge, consider the direction vector formed from:
245 *
246 * top -> bottom
247 *
248 * which is:
249 *
250 * (dx, dy) = (line.p2.x - line.p1.x, line.p2.y - line.p1.y)
251 *
252 * We then define the slope of each edge as dx/dy, (which is the
253 * inverse of the slope typically used in math instruction). We never
254 * compute a slope directly as the value approaches infinity, but we
255 * can derive a slope comparison without division as follows, (where
256 * the ? represents our compare operator).
257 *
258 * 1. slope(a) ? slope(b)
259 * 2. adx/ady ? bdx/bdy
260 * 3. (adx * bdy) ? (bdx * ady)
261 *
262 * Note that from step 2 to step 3 there is no change needed in the
263 * sign of the result since both ady and bdy are guaranteed to be
264 * greater than or equal to 0.
265 *
266 * When using this slope comparison to sort edges, some care is needed
267 * when interpreting the results. Since the slope compare operates on
268 * distance vectors from top to bottom it gives a correct left to
269 * right sort for edges that have a common top point, (such as two
270 * edges with start events at the same location). On the other hand,
271 * the sense of the result will be exactly reversed for two edges that
272 * have a common stop point.
273 */
274static inline int
275_slope_compare (const cairo_bo_edge_t *a,
276 const cairo_bo_edge_t *b)
277{
278 /* XXX: We're assuming here that dx and dy will still fit in 32
279 * bits. That's not true in general as there could be overflow. We
280 * should prevent that before the tessellation algorithm
281 * begins.
282 */
283 int32_t adx = a->edge.line.p2.x - a->edge.line.p1.x;
284 int32_t bdx = b->edge.line.p2.x - b->edge.line.p1.x;
285
286 /* Since the dy's are all positive by construction we can fast
287 * path several common cases.
288 */
289
290 /* First check for vertical lines. */
291 if (adx == 0)
292 return -bdx;
293 if (bdx == 0)
294 return adx;
295
296 /* Then where the two edges point in different directions wrt x. */
297 if ((adx ^ bdx) < 0)
298 return adx;
299
300 /* Finally we actually need to do the general comparison. */
301 {
302 int32_t ady = a->edge.line.p2.y - a->edge.line.p1.y;
303 int32_t bdy = b->edge.line.p2.y - b->edge.line.p1.y;
304 cairo_int64_t adx_bdy = _cairo_int32x32_64_mul (adx, bdy)((int64_t) (adx) * (bdy));
305 cairo_int64_t bdx_ady = _cairo_int32x32_64_mul (bdx, ady)((int64_t) (bdx) * (ady));
306
307 return _cairo_int64_cmp (adx_bdy, bdx_ady)((adx_bdy) == (bdx_ady) ? 0 : (adx_bdy) < (bdx_ady) ? -1 :
1);
308 }
309}
310
311
312/*
313 * We need to compare the x-coordinate of a line for a particular y wrt to a
314 * given x, without loss of precision.
315 *
316 * The x-coordinate along an edge for a given y is:
317 * X = A_x + (Y - A_y) * A_dx / A_dy
318 *
319 * So the inequality we wish to test is:
320 * A_x + (Y - A_y) * A_dx / A_dy ∘ X
321 * where ∘ is our inequality operator.
322 *
323 * By construction, we know that A_dy (and (Y - A_y)) are
324 * all positive, so we can rearrange it thus without causing a sign change:
325 * (Y - A_y) * A_dx ∘ (X - A_x) * A_dy
326 *
327 * Given the assumption that all the deltas fit within 32 bits, we can compute
328 * this comparison directly using 64 bit arithmetic.
329 *
330 * See the similar discussion for _slope_compare() and
331 * edges_compare_x_for_y_general().
332 */
333static int
334edge_compare_for_y_against_x (const cairo_bo_edge_t *a,
335 int32_t y,
336 int32_t x)
337{
338 int32_t adx, ady;
339 int32_t dx, dy;
340 cairo_int64_t L, R;
341
342 if (x < a->edge.line.p1.x && x < a->edge.line.p2.x)
343 return 1;
344 if (x > a->edge.line.p1.x && x > a->edge.line.p2.x)
345 return -1;
346
347 adx = a->edge.line.p2.x - a->edge.line.p1.x;
348 dx = x - a->edge.line.p1.x;
349
350 if (adx == 0)
351 return -dx;
352 if (dx == 0 || (adx ^ dx) < 0)
353 return adx;
354
355 dy = y - a->edge.line.p1.y;
356 ady = a->edge.line.p2.y - a->edge.line.p1.y;
357
358 L = _cairo_int32x32_64_mul (dy, adx)((int64_t) (dy) * (adx));
359 R = _cairo_int32x32_64_mul (dx, ady)((int64_t) (dx) * (ady));
360
361 return _cairo_int64_cmp (L, R)((L) == (R) ? 0 : (L) < (R) ? -1 : 1);
362}
363
364static inline int
365_cairo_bo_sweep_line_compare_edges (const cairo_bo_sweep_line_t *sweep_line,
366 const cairo_bo_edge_t *a,
367 const cairo_bo_edge_t *b)
368{
369 int cmp;
370
371 cmp = _cairo_lines_compare_at_y (&a->edge.line,
372 &b->edge.line,
373 sweep_line->current_y);
374 if (cmp)
375 return cmp;
376
377 /* We've got two collinear edges now. */
378 return b->edge.bottom - a->edge.bottom;
379}
380
381static inline cairo_int64_t
382det32_64 (int32_t a, int32_t b,
383 int32_t c, int32_t d)
384{
385 /* det = a * d - b * c */
386 return _cairo_int64_sub (_cairo_int32x32_64_mul (a, d),((((int64_t) (a) * (d))) - (((int64_t) (b) * (c))))
387 _cairo_int32x32_64_mul (b, c))((((int64_t) (a) * (d))) - (((int64_t) (b) * (c))));
388}
389
390static inline cairo_int128_t
391det64x32_128 (cairo_int64_t a, int32_t b,
392 cairo_int64_t c, int32_t d)
393{
394 /* det = a * d - b * c */
395 return _cairo_int128_sub (_cairo_int64x32_128_mul (a, d),_cairo_uint128_sub(_cairo_int64x64_128_mul(a, ((int64_t) (d))
),_cairo_int64x64_128_mul(c, ((int64_t) (b))))
396 _cairo_int64x32_128_mul (c, b))_cairo_uint128_sub(_cairo_int64x64_128_mul(a, ((int64_t) (d))
),_cairo_int64x64_128_mul(c, ((int64_t) (b))));
397}
398
399/* Compute the intersection of two lines as defined by two edges. The
400 * result is provided as a coordinate pair of 128-bit integers.
401 *
402 * Returns %CAIRO_BO_STATUS_INTERSECTION if there is an intersection or
403 * %CAIRO_BO_STATUS_PARALLEL if the two lines are exactly parallel.
404 */
405static cairo_bool_t
406intersect_lines (cairo_bo_edge_t *a,
407 cairo_bo_edge_t *b,
408 cairo_bo_intersect_point_t *intersection)
409{
410 cairo_int64_t a_det, b_det;
411
412 /* XXX: We're assuming here that dx and dy will still fit in 32
413 * bits. That's not true in general as there could be overflow. We
414 * should prevent that before the tessellation algorithm begins.
415 * What we're doing to mitigate this is to perform clamping in
416 * cairo_bo_tessellate_polygon().
417 */
418 int32_t dx1 = a->edge.line.p1.x - a->edge.line.p2.x;
419 int32_t dy1 = a->edge.line.p1.y - a->edge.line.p2.y;
420
421 int32_t dx2 = b->edge.line.p1.x - b->edge.line.p2.x;
422 int32_t dy2 = b->edge.line.p1.y - b->edge.line.p2.y;
423
424 cairo_int64_t den_det;
425 cairo_int64_t R;
426 cairo_quorem64_t qr;
427
428 den_det = det32_64 (dx1, dy1, dx2, dy2);
429
430 /* Q: Can we determine that the lines do not intersect (within range)
431 * much more cheaply than computing the intersection point i.e. by
432 * avoiding the division?
433 *
434 * X = ax + t * adx = bx + s * bdx;
435 * Y = ay + t * ady = by + s * bdy;
436 * ∴ t * (ady*bdx - bdy*adx) = bdx * (by - ay) + bdy * (ax - bx)
437 * => t * L = R
438 *
439 * Therefore we can reject any intersection (under the criteria for
440 * valid intersection events) if:
441 * L^R < 0 => t < 0, or
442 * L<R => t > 1
443 *
444 * (where top/bottom must at least extend to the line endpoints).
445 *
446 * A similar substitution can be performed for s, yielding:
447 * s * (ady*bdx - bdy*adx) = ady * (ax - bx) - adx * (ay - by)
448 */
449 R = det32_64 (dx2, dy2,
450 b->edge.line.p1.x - a->edge.line.p1.x,
451 b->edge.line.p1.y - a->edge.line.p1.y);
452 if (_cairo_int64_negative (den_det)((den_det) < 0)) {
453 if (_cairo_int64_ge (den_det, R)(!((den_det) < (R))))
454 return FALSE0;
455 } else {
456 if (_cairo_int64_le (den_det, R)(!((R) < (den_det))))
457 return FALSE0;
458 }
459
460 R = det32_64 (dy1, dx1,
461 a->edge.line.p1.y - b->edge.line.p1.y,
462 a->edge.line.p1.x - b->edge.line.p1.x);
463 if (_cairo_int64_negative (den_det)((den_det) < 0)) {
464 if (_cairo_int64_ge (den_det, R)(!((den_det) < (R))))
465 return FALSE0;
466 } else {
467 if (_cairo_int64_le (den_det, R)(!((R) < (den_det))))
468 return FALSE0;
469 }
470
471 /* We now know that the two lines should intersect within range. */
472
473 a_det = det32_64 (a->edge.line.p1.x, a->edge.line.p1.y,
474 a->edge.line.p2.x, a->edge.line.p2.y);
475 b_det = det32_64 (b->edge.line.p1.x, b->edge.line.p1.y,
476 b->edge.line.p2.x, b->edge.line.p2.y);
477
478 /* x = det (a_det, dx1, b_det, dx2) / den_det */
479 qr = _cairo_int_96by64_32x64_divrem (det64x32_128 (a_det, dx1,
480 b_det, dx2),
481 den_det);
482 if (_cairo_int64_eq (qr.rem, den_det)((qr.rem) == (den_det)))
483 return FALSE0;
484#if 0
485 intersection->x.exactness = _cairo_int64_is_zero (qr.rem)((qr.rem) == 0) ? EXACT : INEXACT;
486#else
487 intersection->x.exactness = EXACT;
488 if (! _cairo_int64_is_zero (qr.rem)((qr.rem) == 0)) {
489 if (_cairo_int64_negative (den_det)((den_det) < 0) ^ _cairo_int64_negative (qr.rem)((qr.rem) < 0))
490 qr.rem = _cairo_int64_negate (qr.rem)(-(qr.rem));
491 qr.rem = _cairo_int64_mul (qr.rem, _cairo_int32_to_int64 (2))((qr.rem) * (((int64_t) (2))));
492 if (_cairo_int64_ge (qr.rem, den_det)(!((qr.rem) < (den_det)))) {
493 qr.quo = _cairo_int64_add (qr.quo,((qr.quo) + (((int64_t) (((qr.quo) < 0) ? -1 : 1))))
494 _cairo_int32_to_int64 (_cairo_int64_negative (qr.quo) ? -1 : 1))((qr.quo) + (((int64_t) (((qr.quo) < 0) ? -1 : 1))));
495 } else
496 intersection->x.exactness = INEXACT;
497 }
498#endif
499 intersection->x.ordinate = _cairo_int64_to_int32 (qr.quo)((int32_t) (qr.quo));
500
501 /* y = det (a_det, dy1, b_det, dy2) / den_det */
502 qr = _cairo_int_96by64_32x64_divrem (det64x32_128 (a_det, dy1,
503 b_det, dy2),
504 den_det);
505 if (_cairo_int64_eq (qr.rem, den_det)((qr.rem) == (den_det)))
506 return FALSE0;
507#if 0
508 intersection->y.exactness = _cairo_int64_is_zero (qr.rem)((qr.rem) == 0) ? EXACT : INEXACT;
509#else
510 intersection->y.exactness = EXACT;
511 if (! _cairo_int64_is_zero (qr.rem)((qr.rem) == 0)) {
512 if (_cairo_int64_negative (den_det)((den_det) < 0) ^ _cairo_int64_negative (qr.rem)((qr.rem) < 0))
513 qr.rem = _cairo_int64_negate (qr.rem)(-(qr.rem));
514 qr.rem = _cairo_int64_mul (qr.rem, _cairo_int32_to_int64 (2))((qr.rem) * (((int64_t) (2))));
515 if (_cairo_int64_ge (qr.rem, den_det)(!((qr.rem) < (den_det)))) {
516 qr.quo = _cairo_int64_add (qr.quo,((qr.quo) + (((int64_t) (((qr.quo) < 0) ? -1 : 1))))
517 _cairo_int32_to_int64 (_cairo_int64_negative (qr.quo) ? -1 : 1))((qr.quo) + (((int64_t) (((qr.quo) < 0) ? -1 : 1))));
518 } else
519 intersection->y.exactness = INEXACT;
520 }
521#endif
522 intersection->y.ordinate = _cairo_int64_to_int32 (qr.quo)((int32_t) (qr.quo));
523
524 return TRUE1;
525}
526
527static int
528_cairo_bo_intersect_ordinate_32_compare (cairo_bo_intersect_ordinate_t a,
529 int32_t b)
530{
531 /* First compare the quotient */
532 if (a.ordinate > b)
533 return +1;
534 if (a.ordinate < b)
535 return -1;
536 /* With quotient identical, if remainder is 0 then compare equal */
537 /* Otherwise, the non-zero remainder makes a > b */
538 return INEXACT == a.exactness;
539}
540
541/* Does the given edge contain the given point. The point must already
542 * be known to be contained within the line determined by the edge,
543 * (most likely the point results from an intersection of this edge
544 * with another).
545 *
546 * If we had exact arithmetic, then this function would simply be a
547 * matter of examining whether the y value of the point lies within
548 * the range of y values of the edge. But since intersection points
549 * are not exact due to being rounded to the nearest integer within
550 * the available precision, we must also examine the x value of the
551 * point.
552 *
553 * The definition of "contains" here is that the given intersection
554 * point will be seen by the sweep line after the start event for the
555 * given edge and before the stop event for the edge. See the comments
556 * in the implementation for more details.
557 */
558static cairo_bool_t
559_cairo_bo_edge_contains_intersect_point (cairo_bo_edge_t *edge,
560 cairo_bo_intersect_point_t *point)
561{
562 int cmp_top, cmp_bottom;
563
564 /* XXX: When running the actual algorithm, we don't actually need to
565 * compare against edge->top at all here, since any intersection above
566 * top is eliminated early via a slope comparison. We're leaving these
567 * here for now only for the sake of the quadratic-time intersection
568 * finder which needs them.
569 */
570
571 cmp_top = _cairo_bo_intersect_ordinate_32_compare (point->y,
572 edge->edge.top);
573 cmp_bottom = _cairo_bo_intersect_ordinate_32_compare (point->y,
574 edge->edge.bottom);
575
576 if (cmp_top < 0 || cmp_bottom > 0)
577 {
578 return FALSE0;
579 }
580
581 if (cmp_top > 0 && cmp_bottom < 0)
582 {
583 return TRUE1;
584 }
585
586 /* At this stage, the point lies on the same y value as either
587 * edge->top or edge->bottom, so we have to examine the x value in
588 * order to properly determine containment. */
589
590 /* If the y value of the point is the same as the y value of the
591 * top of the edge, then the x value of the point must be greater
592 * to be considered as inside the edge. Similarly, if the y value
593 * of the point is the same as the y value of the bottom of the
594 * edge, then the x value of the point must be less to be
595 * considered as inside. */
596
597 if (cmp_top == 0) {
598 cairo_fixed_t top_x;
599
600 top_x = _line_compute_intersection_x_for_y (&edge->edge.line,
601 edge->edge.top);
602 return _cairo_bo_intersect_ordinate_32_compare (point->x, top_x) > 0;
603 } else { /* cmp_bottom == 0 */
604 cairo_fixed_t bot_x;
605
606 bot_x = _line_compute_intersection_x_for_y (&edge->edge.line,
607 edge->edge.bottom);
608 return _cairo_bo_intersect_ordinate_32_compare (point->x, bot_x) < 0;
609 }
610}
611
612/* Compute the intersection of two edges. The result is provided as a
613 * coordinate pair of 128-bit integers.
614 *
615 * Returns %CAIRO_BO_STATUS_INTERSECTION if there is an intersection
616 * that is within both edges, %CAIRO_BO_STATUS_NO_INTERSECTION if the
617 * intersection of the lines defined by the edges occurs outside of
618 * one or both edges, and %CAIRO_BO_STATUS_PARALLEL if the two edges
619 * are exactly parallel.
620 *
621 * Note that when determining if a candidate intersection is "inside"
622 * an edge, we consider both the infinitesimal shortening and the
623 * infinitesimal tilt rules described by John Hobby. Specifically, if
624 * the intersection is exactly the same as an edge point, it is
625 * effectively outside (no intersection is returned). Also, if the
626 * intersection point has the same
627 */
628static cairo_bool_t
629_cairo_bo_edge_intersect (cairo_bo_edge_t *a,
630 cairo_bo_edge_t *b,
631 cairo_bo_point32_t *intersection)
632{
633 cairo_bo_intersect_point_t quorem;
634
635 if (! intersect_lines (a, b, &quorem))
636 return FALSE0;
637
638 if (! _cairo_bo_edge_contains_intersect_point (a, &quorem))
639 return FALSE0;
640
641 if (! _cairo_bo_edge_contains_intersect_point (b, &quorem))
642 return FALSE0;
643
644 /* Now that we've correctly compared the intersection point and
645 * determined that it lies within the edge, then we know that we
646 * no longer need any more bits of storage for the intersection
647 * than we do for our edge coordinates. We also no longer need the
648 * remainder from the division. */
649 intersection->x = quorem.x.ordinate;
650 intersection->y = quorem.y.ordinate;
651
652 return TRUE1;
653}
654
655static inline int
656cairo_bo_event_compare (const cairo_bo_event_t *a,
657 const cairo_bo_event_t *b)
658{
659 int cmp;
660
661 cmp = _cairo_bo_point32_compare (&a->point, &b->point);
662 if (cmp)
663 return cmp;
664
665 cmp = a->type - b->type;
666 if (cmp)
667 return cmp;
668
669 return a - b;
670}
671
672static inline void
673_pqueue_init (pqueue_t *pq)
674{
675 pq->max_size = ARRAY_LENGTH (pq->elements_embedded)((int) (sizeof (pq->elements_embedded) / sizeof (pq->elements_embedded
[0])));
676 pq->size = 0;
677
678 pq->elements = pq->elements_embedded;
679}
680
681static inline void
682_pqueue_fini (pqueue_t *pq)
683{
684 if (pq->elements != pq->elements_embedded)
685 free (pq->elements);
686}
687
688static cairo_status_t
689_pqueue_grow (pqueue_t *pq)
690{
691 cairo_bo_event_t **new_elements;
692 pq->max_size *= 2;
693
694 if (pq->elements == pq->elements_embedded) {
695 new_elements = _cairo_malloc_ab (pq->max_size,
696 sizeof (cairo_bo_event_t *));
697 if (unlikely (new_elements == NULL)(__builtin_expect (!!(new_elements == ((void*)0)), 0)))
698 return _cairo_error (CAIRO_STATUS_NO_MEMORY);
699
700 memcpy (new_elements, pq->elements_embedded,
701 sizeof (pq->elements_embedded));
702 } else {
703 new_elements = _cairo_realloc_ab (pq->elements,
704 pq->max_size,
705 sizeof (cairo_bo_event_t *));
706 if (unlikely (new_elements == NULL)(__builtin_expect (!!(new_elements == ((void*)0)), 0)))
707 return _cairo_error (CAIRO_STATUS_NO_MEMORY);
708 }
709
710 pq->elements = new_elements;
711 return CAIRO_STATUS_SUCCESS;
712}
713
714static inline cairo_status_t
715_pqueue_push (pqueue_t *pq, cairo_bo_event_t *event)
716{
717 cairo_bo_event_t **elements;
718 int i, parent;
719
720 if (unlikely (pq->size + 1 == pq->max_size)(__builtin_expect (!!(pq->size + 1 == pq->max_size), 0)
)) {
721 cairo_status_t status;
722
723 status = _pqueue_grow (pq);
724 if (unlikely (status)(__builtin_expect (!!(status), 0)))
725 return status;
726 }
727
728 elements = pq->elements;
729
730 for (i = ++pq->size;
731 i != PQ_FIRST_ENTRY1 &&
732 cairo_bo_event_compare (event,
733 elements[parent = PQ_PARENT_INDEX (i)((i) >> 1)]) < 0;
734 i = parent)
735 {
736 elements[i] = elements[parent];
737 }
738
739 elements[i] = event;
740
741 return CAIRO_STATUS_SUCCESS;
742}
743
744static inline void
745_pqueue_pop (pqueue_t *pq)
746{
747 cairo_bo_event_t **elements = pq->elements;
748 cairo_bo_event_t *tail;
749 int child, i;
750
751 tail = elements[pq->size--];
752 if (pq->size == 0) {
753 elements[PQ_FIRST_ENTRY1] = NULL((void*)0);
754 return;
755 }
756
757 for (i = PQ_FIRST_ENTRY1;
758 (child = PQ_LEFT_CHILD_INDEX (i)((i) << 1)) <= pq->size;
759 i = child)
760 {
761 if (child != pq->size &&
762 cairo_bo_event_compare (elements[child+1],
763 elements[child]) < 0)
764 {
765 child++;
766 }
767
768 if (cairo_bo_event_compare (elements[child], tail) >= 0)
769 break;
770
771 elements[i] = elements[child];
772 }
773 elements[i] = tail;
774}
775
776static inline cairo_status_t
777_cairo_bo_event_queue_insert (cairo_bo_event_queue_t *queue,
778 cairo_bo_event_type_t type,
779 cairo_bo_edge_t *e1,
780 cairo_bo_edge_t *e2,
781 const cairo_point_t *point)
782{
783 cairo_bo_queue_event_t *event;
784
785 event = _cairo_freepool_alloc (&queue->pool);
786 if (unlikely (event == NULL)(__builtin_expect (!!(event == ((void*)0)), 0)))
787 return _cairo_error (CAIRO_STATUS_NO_MEMORY);
788
789 event->type = type;
790 event->e1 = e1;
791 event->e2 = e2;
792 event->point = *point;
793
794 return _pqueue_push (&queue->pqueue, (cairo_bo_event_t *) event);
795}
796
797static void
798_cairo_bo_event_queue_delete (cairo_bo_event_queue_t *queue,
799 cairo_bo_event_t *event)
800{
801 _cairo_freepool_free (&queue->pool, event);
802}
803
804static cairo_bo_event_t *
805_cairo_bo_event_dequeue (cairo_bo_event_queue_t *event_queue)
806{
807 cairo_bo_event_t *event, *cmp;
808
809 event = event_queue->pqueue.elements[PQ_FIRST_ENTRY1];
810 cmp = *event_queue->start_events;
811 if (event == NULL((void*)0) ||
812 (cmp != NULL((void*)0) && cairo_bo_event_compare (cmp, event) < 0))
813 {
814 event = cmp;
815 event_queue->start_events++;
816 }
817 else
818 {
819 _pqueue_pop (&event_queue->pqueue);
820 }
821
822 return event;
823}
824
825CAIRO_COMBSORT_DECLARE (_cairo_bo_event_queue_sort,static void _cairo_bo_event_queue_sort (cairo_bo_event_t * *base
, unsigned int nmemb) { unsigned int gap = nmemb; unsigned int
i, j; int swapped; do { gap = _cairo_combsort_newgap (gap); swapped
= gap > 1; for (i = 0; i < nmemb-gap ; i++) { j = i + gap
; if (cairo_bo_event_compare (base[i], base[j]) > 0 ) { cairo_bo_event_t
* tmp; tmp = base[i]; base[i] = base[j]; base[j] = tmp; swapped
= 1; } } } while (swapped); }
16
←
The value 0 is assigned to 'i'
→
17
←
Loop condition is true. Entering loop body
→
18
←
1st function call argument is an uninitialized value
826 cairo_bo_event_t *,static void _cairo_bo_event_queue_sort (cairo_bo_event_t * *base
, unsigned int nmemb) { unsigned int gap = nmemb; unsigned int
i, j; int swapped; do { gap = _cairo_combsort_newgap (gap); swapped
= gap > 1; for (i = 0; i < nmemb-gap ; i++) { j = i + gap
; if (cairo_bo_event_compare (base[i], base[j]) > 0 ) { cairo_bo_event_t
* tmp; tmp = base[i]; base[i] = base[j]; base[j] = tmp; swapped
= 1; } } } while (swapped); }
827 cairo_bo_event_compare)static void _cairo_bo_event_queue_sort (cairo_bo_event_t * *base
, unsigned int nmemb) { unsigned int gap = nmemb; unsigned int
i, j; int swapped; do { gap = _cairo_combsort_newgap (gap); swapped
= gap > 1; for (i = 0; i < nmemb-gap ; i++) { j = i + gap
; if (cairo_bo_event_compare (base[i], base[j]) > 0 ) { cairo_bo_event_t
* tmp; tmp = base[i]; base[i] = base[j]; base[j] = tmp; swapped
= 1; } } } while (swapped); }
828
829static void
830_cairo_bo_event_queue_init (cairo_bo_event_queue_t *event_queue,
831 cairo_bo_event_t **start_events,
832 int num_events)
833{
834 event_queue->start_events = start_events;
835
836 _cairo_freepool_init (&event_queue->pool,
837 sizeof (cairo_bo_queue_event_t));
838 _pqueue_init (&event_queue->pqueue);
839 event_queue->pqueue.elements[PQ_FIRST_ENTRY1] = NULL((void*)0);
840}
841
842static cairo_status_t
843_cairo_bo_event_queue_insert_stop (cairo_bo_event_queue_t *event_queue,
844 cairo_bo_edge_t *edge)
845{
846 cairo_bo_point32_t point;
847
848 point.y = edge->edge.bottom;
849 point.x = _line_compute_intersection_x_for_y (&edge->edge.line,
850 point.y);
851 return _cairo_bo_event_queue_insert (event_queue,
852 CAIRO_BO_EVENT_TYPE_STOP,
853 edge, NULL((void*)0),
854 &point);
855}
856
857static void
858_cairo_bo_event_queue_fini (cairo_bo_event_queue_t *event_queue)
859{
860 _pqueue_fini (&event_queue->pqueue);
861 _cairo_freepool_fini (&event_queue->pool);
862}
863
864static inline cairo_status_t
865_cairo_bo_event_queue_insert_if_intersect_below_current_y (cairo_bo_event_queue_t *event_queue,
866 cairo_bo_edge_t *left,
867 cairo_bo_edge_t *right)
868{
869 cairo_bo_point32_t intersection;
870
871 if (MAX (left->edge.line.p1.x, left->edge.line.p2.x)((left->edge.line.p1.x) > (left->edge.line.p2.x) ? (
left->edge.line.p1.x) : (left->edge.line.p2.x)) <=
872 MIN (right->edge.line.p1.x, right->edge.line.p2.x)((right->edge.line.p1.x) < (right->edge.line.p2.x) ?
(right->edge.line.p1.x) : (right->edge.line.p2.x)))
873 return CAIRO_STATUS_SUCCESS;
874
875 if (cairo_lines_equal (&left->edge.line, &right->edge.line))
876 return CAIRO_STATUS_SUCCESS;
877
878 /* The names "left" and "right" here are correct descriptions of
879 * the order of the two edges within the active edge list. So if a
880 * slope comparison also puts left less than right, then we know
881 * that the intersection of these two segments has already
882 * occurred before the current sweep line position. */
883 if (_slope_compare (left, right) <= 0)
884 return CAIRO_STATUS_SUCCESS;
885
886 if (! _cairo_bo_edge_intersect (left, right, &intersection))
887 return CAIRO_STATUS_SUCCESS;
888
889 return _cairo_bo_event_queue_insert (event_queue,
890 CAIRO_BO_EVENT_TYPE_INTERSECTION,
891 left, right,
892 &intersection);
893}
894
895static void
896_cairo_bo_sweep_line_init (cairo_bo_sweep_line_t *sweep_line)
897{
898 sweep_line->head = NULL((void*)0);
899 sweep_line->stopped = NULL((void*)0);
900 sweep_line->current_y = INT32_MIN(-2147483647-1);
901 sweep_line->current_edge = NULL((void*)0);
902}
903
904static void
905_cairo_bo_sweep_line_insert (cairo_bo_sweep_line_t *sweep_line,
906 cairo_bo_edge_t *edge)
907{
908 if (sweep_line->current_edge != NULL((void*)0)) {
909 cairo_bo_edge_t *prev, *next;
910 int cmp;
911
912 cmp = _cairo_bo_sweep_line_compare_edges (sweep_line,
913 sweep_line->current_edge,
914 edge);
915 if (cmp < 0) {
916 prev = sweep_line->current_edge;
917 next = prev->next;
918 while (next != NULL((void*)0) &&
919 _cairo_bo_sweep_line_compare_edges (sweep_line,
920 next, edge) < 0)
921 {
922 prev = next, next = prev->next;
923 }
924
925 prev->next = edge;
926 edge->prev = prev;
927 edge->next = next;
928 if (next != NULL((void*)0))
929 next->prev = edge;
930 } else if (cmp > 0) {
931 next = sweep_line->current_edge;
932 prev = next->prev;
933 while (prev != NULL((void*)0) &&
934 _cairo_bo_sweep_line_compare_edges (sweep_line,
935 prev, edge) > 0)
936 {
937 next = prev, prev = next->prev;
938 }
939
940 next->prev = edge;
941 edge->next = next;
942 edge->prev = prev;
943 if (prev != NULL((void*)0))
944 prev->next = edge;
945 else
946 sweep_line->head = edge;
947 } else {
948 prev = sweep_line->current_edge;
949 edge->prev = prev;
950 edge->next = prev->next;
951 if (prev->next != NULL((void*)0))
952 prev->next->prev = edge;
953 prev->next = edge;
954 }
955 } else {
956 sweep_line->head = edge;
957 edge->next = NULL((void*)0);
958 }
959
960 sweep_line->current_edge = edge;
961}
962
963static void
964_cairo_bo_sweep_line_delete (cairo_bo_sweep_line_t *sweep_line,
965 cairo_bo_edge_t *edge)
966{
967 if (edge->prev != NULL((void*)0))
968 edge->prev->next = edge->next;
969 else
970 sweep_line->head = edge->next;
971
972 if (edge->next != NULL((void*)0))
973 edge->next->prev = edge->prev;
974
975 if (sweep_line->current_edge == edge)
976 sweep_line->current_edge = edge->prev ? edge->prev : edge->next;
977}
978
979static void
980_cairo_bo_sweep_line_swap (cairo_bo_sweep_line_t *sweep_line,
981 cairo_bo_edge_t *left,
982 cairo_bo_edge_t *right)
983{
984 if (left->prev != NULL((void*)0))
985 left->prev->next = right;
986 else
987 sweep_line->head = right;
988
989 if (right->next != NULL((void*)0))
990 right->next->prev = left;
991
992 left->next = right->next;
993 right->next = left;
994
995 right->prev = left->prev;
996 left->prev = right;
997}
998
999#if DEBUG_PRINT_STATE0
1000static void
1001_cairo_bo_edge_print (cairo_bo_edge_t *edge)
1002{
1003 printf ("(0x%x, 0x%x)-(0x%x, 0x%x)",
1004 edge->edge.line.p1.x, edge->edge.line.p1.y,
1005 edge->edge.line.p2.x, edge->edge.line.p2.y);
1006}
1007
1008static void
1009_cairo_bo_event_print (cairo_bo_event_t *event)
1010{
1011 switch (event->type) {
1012 case CAIRO_BO_EVENT_TYPE_START:
1013 printf ("Start: ");
1014 break;
1015 case CAIRO_BO_EVENT_TYPE_STOP:
1016 printf ("Stop: ");
1017 break;
1018 case CAIRO_BO_EVENT_TYPE_INTERSECTION:
1019 printf ("Intersection: ");
1020 break;
1021 }
1022 printf ("(%d, %d)\t", event->point.x, event->point.y);
1023 _cairo_bo_edge_print (event->e1);
1024 if (event->type == CAIRO_BO_EVENT_TYPE_INTERSECTION) {
1025 printf (" X ");
1026 _cairo_bo_edge_print (event->e2);
1027 }
1028 printf ("\n");
1029}
1030
1031static void
1032_cairo_bo_event_queue_print (cairo_bo_event_queue_t *event_queue)
1033{
1034 /* XXX: fixme to print the start/stop array too. */
1035 printf ("Event queue:\n");
1036}
1037
1038static void
1039_cairo_bo_sweep_line_print (cairo_bo_sweep_line_t *sweep_line)
1040{
1041 cairo_bool_t first = TRUE1;
1042 cairo_bo_edge_t *edge;
1043
1044 printf ("Sweep line from edge list: ");
1045 first = TRUE1;
1046 for (edge = sweep_line->head;
1047 edge;
1048 edge = edge->next)
1049 {
1050 if (!first)
1051 printf (", ");
1052 _cairo_bo_edge_print (edge);
1053 first = FALSE0;
1054 }
1055 printf ("\n");
1056}
1057
1058static void
1059print_state (const char *msg,
1060 cairo_bo_event_t *event,
1061 cairo_bo_event_queue_t *event_queue,
1062 cairo_bo_sweep_line_t *sweep_line)
1063{
1064 printf ("%s ", msg);
1065 _cairo_bo_event_print (event);
1066 _cairo_bo_event_queue_print (event_queue);
1067 _cairo_bo_sweep_line_print (sweep_line);
1068 printf ("\n");
1069}
1070#endif
1071
1072#if DEBUG_EVENTS0
1073static void CAIRO_PRINTF_FORMAT (1, 2)__attribute__((__format__(__printf__, 1, 2)))
1074event_log (const char *fmt, ...)
1075{
1076 FILE *file;
1077
1078 if (getenv ("CAIRO_DEBUG_EVENTS") == NULL((void*)0))
1079 return;
1080
1081 file = fopen ("bo-events.txt", "a");
1082 if (file != NULL((void*)0)) {
1083 va_list ap;
1084
1085 va_start (ap, fmt)__builtin_va_start(ap, fmt);
1086 vfprintf (file, fmt, ap);
1087 va_end (ap)__builtin_va_end(ap);
1088
1089 fclose (file);
1090 }
1091}
1092#endif
1093
1094#define HAS_COLINEAR(a, b)((cairo_bo_edge_t *)(((uintptr_t)(a))&~1) == (b)) ((cairo_bo_edge_t *)(((uintptr_t)(a))&~1) == (b))
1095#define IS_COLINEAR(e)(((uintptr_t)(e))&1) (((uintptr_t)(e))&1)
1096#define MARK_COLINEAR(e, v)((cairo_bo_edge_t *)(((uintptr_t)(e))|(v))) ((cairo_bo_edge_t *)(((uintptr_t)(e))|(v)))
1097
1098static inline cairo_bool_t
1099edges_colinear (cairo_bo_edge_t *a, const cairo_bo_edge_t *b)
1100{
1101 unsigned p;
1102
1103 if (HAS_COLINEAR(a->colinear, b)((cairo_bo_edge_t *)(((uintptr_t)(a->colinear))&~1) ==
(b)))
1104 return IS_COLINEAR(a->colinear)(((uintptr_t)(a->colinear))&1);
1105
1106 if (HAS_COLINEAR(b->colinear, a)((cairo_bo_edge_t *)(((uintptr_t)(b->colinear))&~1) ==
(a))) {
1107 p = IS_COLINEAR(b->colinear)(((uintptr_t)(b->colinear))&1);
1108 a->colinear = MARK_COLINEAR(b, p)((cairo_bo_edge_t *)(((uintptr_t)(b))|(p)));
1109 return p;
1110 }
1111
1112 p = 0;
1113 p |= (a->edge.line.p1.x == b->edge.line.p1.x) << 0;
1114 p |= (a->edge.line.p1.y == b->edge.line.p1.y) << 1;
1115 p |= (a->edge.line.p2.x == b->edge.line.p2.x) << 3;
1116 p |= (a->edge.line.p2.y == b->edge.line.p2.y) << 4;
1117 if (p == ((1 << 0) | (1 << 1) | (1 << 3) | (1 << 4))) {
1118 a->colinear = MARK_COLINEAR(b, 1)((cairo_bo_edge_t *)(((uintptr_t)(b))|(1)));
1119 return TRUE1;
1120 }
1121
1122 if (_slope_compare (a, b)) {
1123 a->colinear = MARK_COLINEAR(b, 0)((cairo_bo_edge_t *)(((uintptr_t)(b))|(0)));
1124 return FALSE0;
1125 }
1126
1127 /* The choice of y is not truly arbitrary since we must guarantee that it
1128 * is greater than the start of either line.
1129 */
1130 if (p != 0) {
1131 /* colinear if either end-point are coincident */
1132 p = (((p >> 1) & p) & 5) != 0;
1133 } else if (a->edge.line.p1.y < b->edge.line.p1.y) {
1134 p = edge_compare_for_y_against_x (b,
1135 a->edge.line.p1.y,
1136 a->edge.line.p1.x) == 0;
1137 } else {
1138 p = edge_compare_for_y_against_x (a,
1139 b->edge.line.p1.y,
1140 b->edge.line.p1.x) == 0;
1141 }
1142
1143 a->colinear = MARK_COLINEAR(b, p)((cairo_bo_edge_t *)(((uintptr_t)(b))|(p)));
1144 return p;
1145}
1146
1147/* Adds the trapezoid, if any, of the left edge to the #cairo_traps_t */
1148static void
1149_cairo_bo_edge_end_trap (cairo_bo_edge_t *left,
1150 int32_t bot,
1151 cairo_traps_t *traps)
1152{
1153 cairo_bo_trap_t *trap = &left->deferred_trap;
1154
1155 /* Only emit (trivial) non-degenerate trapezoids with positive height. */
1156 if (likely (trap->top < bot)(__builtin_expect (!!(trap->top < bot), 1))) {
1157 _cairo_traps_add_trap (traps,
1158 trap->top, bot,
1159 &left->edge.line, &trap->right->edge.line);
1160
1161#if DEBUG_PRINT_STATE0
1162 printf ("Deferred trap: left=(%x, %x)-(%x,%x) "
1163 "right=(%x,%x)-(%x,%x) top=%x, bot=%x\n",
1164 left->edge.line.p1.x, left->edge.line.p1.y,
1165 left->edge.line.p2.x, left->edge.line.p2.y,
1166 trap->right->edge.line.p1.x, trap->right->edge.line.p1.y,
1167 trap->right->edge.line.p2.x, trap->right->edge.line.p2.y,
1168 trap->top, bot);
1169#endif
1170#if DEBUG_EVENTS0
1171 event_log ("end trap: %lu %lu %d %d\n",
1172 (long) left,
1173 (long) trap->right,
1174 trap->top,
1175 bot);
1176#endif
1177 }
1178
1179 trap->right = NULL((void*)0);
1180}
1181
1182
1183/* Start a new trapezoid at the given top y coordinate, whose edges
1184 * are `edge' and `edge->next'. If `edge' already has a trapezoid,
1185 * then either add it to the traps in `traps', if the trapezoid's
1186 * right edge differs from `edge->next', or do nothing if the new
1187 * trapezoid would be a continuation of the existing one. */
1188static inline void
1189_cairo_bo_edge_start_or_continue_trap (cairo_bo_edge_t *left,
1190 cairo_bo_edge_t *right,
1191 int top,
1192 cairo_traps_t *traps)
1193{
1194 if (left->deferred_trap.right == right)
1195 return;
1196
1197 assert (right)((void) sizeof ((right) ? 1 : 0), __extension__ ({ if (right)
; else __assert_fail ("right", "/root/firefox-clang/gfx/cairo/cairo/src/cairo-bentley-ottmann.c"
, 1197, __extension__ __PRETTY_FUNCTION__); }));
1198 if (left->deferred_trap.right != NULL((void*)0)) {
1199 if (edges_colinear (left->deferred_trap.right, right))
1200 {
1201 /* continuation on right, so just swap edges */
1202 left->deferred_trap.right = right;
1203 return;
1204 }
1205
1206 _cairo_bo_edge_end_trap (left, top, traps);
1207 }
1208
1209 if (! edges_colinear (left, right)) {
1210 left->deferred_trap.top = top;
1211 left->deferred_trap.right = right;
1212
1213#if DEBUG_EVENTS0
1214 event_log ("begin trap: %lu %lu %d\n",
1215 (long) left,
1216 (long) right,
1217 top);
1218#endif
1219 }
1220}
1221
1222static inline void
1223_active_edges_to_traps (cairo_bo_edge_t *pos,
1224 int32_t top,
1225 unsigned mask,
1226 cairo_traps_t *traps)
1227{
1228 cairo_bo_edge_t *left;
1229 int in_out;
1230
1231
1232#if DEBUG_PRINT_STATE0
1233 printf ("Processing active edges for %x\n", top);
1234#endif
1235
1236 in_out = 0;
1237 left = pos;
1238 while (pos != NULL((void*)0)) {
1239 if (pos != left && pos->deferred_trap.right) {
1240 /* XXX It shouldn't be possible to here with 2 deferred traps
1241 * on colinear edges... See bug-bo-rictoz.
1242 */
1243 if (left->deferred_trap.right == NULL((void*)0) &&
1244 edges_colinear (left, pos))
1245 {
1246 /* continuation on left */
1247 left->deferred_trap = pos->deferred_trap;
1248 pos->deferred_trap.right = NULL((void*)0);
1249 }
1250 else
1251 {
1252 _cairo_bo_edge_end_trap (pos, top, traps);
1253 }
1254 }
1255
1256 in_out += pos->edge.dir;
1257 if ((in_out & mask) == 0) {
1258 /* skip co-linear edges */
1259 if (pos->next == NULL((void*)0) || ! edges_colinear (pos, pos->next)) {
1260 _cairo_bo_edge_start_or_continue_trap (left, pos, top, traps);
1261 left = pos->next;
1262 }
1263 }
1264
1265 pos = pos->next;
1266 }
1267}
1268
1269/* Execute a single pass of the Bentley-Ottmann algorithm on edges,
1270 * generating trapezoids according to the fill_rule and appending them
1271 * to traps. */
1272static cairo_status_t
1273_cairo_bentley_ottmann_tessellate_bo_edges (cairo_bo_event_t **start_events,
1274 int num_events,
1275 unsigned fill_rule,
1276 cairo_traps_t *traps,
1277 int *num_intersections)
1278{
1279 cairo_status_t status;
1280 int intersection_count = 0;
1281 cairo_bo_event_queue_t event_queue;
1282 cairo_bo_sweep_line_t sweep_line;
1283 cairo_bo_event_t *event;
1284 cairo_bo_edge_t *left, *right;
1285 cairo_bo_edge_t *e1, *e2;
1286
1287 /* convert the fill_rule into a winding mask */
1288 if (fill_rule == CAIRO_FILL_RULE_WINDING)
1289 fill_rule = (unsigned) -1;
1290 else
1291 fill_rule = 1;
1292
1293#if DEBUG_EVENTS0
1294 {
1295 int i;
1296
1297 for (i = 0; i < num_events; i++) {
1298 cairo_bo_start_event_t *event =
1299 ((cairo_bo_start_event_t **) start_events)[i];
1300 event_log ("edge: %lu (%d, %d) (%d, %d) (%d, %d) %d\n",
1301 (long) &events[i].edge,
1302 event->edge.edge.line.p1.x,
1303 event->edge.edge.line.p1.y,
1304 event->edge.edge.line.p2.x,
1305 event->edge.edge.line.p2.y,
1306 event->edge.top,
1307 event->edge.bottom,
1308 event->edge.edge.dir);
1309 }
1310 }
1311#endif
1312
1313 _cairo_bo_event_queue_init (&event_queue, start_events, num_events);
1314 _cairo_bo_sweep_line_init (&sweep_line);
1315
1316 while ((event = _cairo_bo_event_dequeue (&event_queue))) {
1317 if (event->point.y != sweep_line.current_y) {
1318 for (e1 = sweep_line.stopped; e1; e1 = e1->next) {
1319 if (e1->deferred_trap.right != NULL((void*)0)) {
1320 _cairo_bo_edge_end_trap (e1,
1321 e1->edge.bottom,
1322 traps);
1323 }
1324 }
1325 sweep_line.stopped = NULL((void*)0);
1326
1327 _active_edges_to_traps (sweep_line.head,
1328 sweep_line.current_y,
1329 fill_rule, traps);
1330
1331 sweep_line.current_y = event->point.y;
1332 }
1333
1334#if DEBUG_EVENTS0
1335 event_log ("event: %d (%ld, %ld) %lu, %lu\n",
1336 event->type,
1337 (long) event->point.x,
1338 (long) event->point.y,
1339 (long) event->e1,
1340 (long) event->e2);
1341#endif
1342
1343 switch (event->type) {
1344 case CAIRO_BO_EVENT_TYPE_START:
1345 e1 = &((cairo_bo_start_event_t *) event)->edge;
1346
1347 _cairo_bo_sweep_line_insert (&sweep_line, e1);
1348
1349 status = _cairo_bo_event_queue_insert_stop (&event_queue, e1);
1350 if (unlikely (status)(__builtin_expect (!!(status), 0)))
1351 goto unwind;
1352
1353 /* check to see if this is a continuation of a stopped edge */
1354 /* XXX change to an infinitesimal lengthening rule */
1355 for (left = sweep_line.stopped; left; left = left->next) {
1356 if (e1->edge.top <= left->edge.bottom &&
1357 edges_colinear (e1, left))
1358 {
1359 e1->deferred_trap = left->deferred_trap;
1360 if (left->prev != NULL((void*)0))
1361 left->prev = left->next;
1362 else
1363 sweep_line.stopped = left->next;
1364 if (left->next != NULL((void*)0))
1365 left->next->prev = left->prev;
1366 break;
1367 }
1368 }
1369
1370 left = e1->prev;
1371 right = e1->next;
1372
1373 if (left != NULL((void*)0)) {
1374 status = _cairo_bo_event_queue_insert_if_intersect_below_current_y (&event_queue, left, e1);
1375 if (unlikely (status)(__builtin_expect (!!(status), 0)))
1376 goto unwind;
1377 }
1378
1379 if (right != NULL((void*)0)) {
1380 status = _cairo_bo_event_queue_insert_if_intersect_below_current_y (&event_queue, e1, right);
1381 if (unlikely (status)(__builtin_expect (!!(status), 0)))
1382 goto unwind;
1383 }
1384
1385 break;
1386
1387 case CAIRO_BO_EVENT_TYPE_STOP:
1388 e1 = ((cairo_bo_queue_event_t *) event)->e1;
1389 _cairo_bo_event_queue_delete (&event_queue, event);
1390
1391 left = e1->prev;
1392 right = e1->next;
1393
1394 _cairo_bo_sweep_line_delete (&sweep_line, e1);
1395
1396 /* first, check to see if we have a continuation via a fresh edge */
1397 if (e1->deferred_trap.right != NULL((void*)0)) {
1398 e1->next = sweep_line.stopped;
1399 if (sweep_line.stopped != NULL((void*)0))
1400 sweep_line.stopped->prev = e1;
1401 sweep_line.stopped = e1;
1402 e1->prev = NULL((void*)0);
1403 }
1404
1405 if (left != NULL((void*)0) && right != NULL((void*)0)) {
1406 status = _cairo_bo_event_queue_insert_if_intersect_below_current_y (&event_queue, left, right);
1407 if (unlikely (status)(__builtin_expect (!!(status), 0)))
1408 goto unwind;
1409 }
1410
1411 break;
1412
1413 case CAIRO_BO_EVENT_TYPE_INTERSECTION:
1414 e1 = ((cairo_bo_queue_event_t *) event)->e1;
1415 e2 = ((cairo_bo_queue_event_t *) event)->e2;
1416 _cairo_bo_event_queue_delete (&event_queue, event);
1417
1418 /* skip this intersection if its edges are not adjacent */
1419 if (e2 != e1->next)
1420 break;
1421
1422 intersection_count++;
1423
1424 left = e1->prev;
1425 right = e2->next;
1426
1427 _cairo_bo_sweep_line_swap (&sweep_line, e1, e2);
1428
1429 /* after the swap e2 is left of e1 */
1430
1431 if (left != NULL((void*)0)) {
1432 status = _cairo_bo_event_queue_insert_if_intersect_below_current_y (&event_queue, left, e2);
1433 if (unlikely (status)(__builtin_expect (!!(status), 0)))
1434 goto unwind;
1435 }
1436
1437 if (right != NULL((void*)0)) {
1438 status = _cairo_bo_event_queue_insert_if_intersect_below_current_y (&event_queue, e1, right);
1439 if (unlikely (status)(__builtin_expect (!!(status), 0)))
1440 goto unwind;
1441 }
1442
1443 break;
1444 }
1445 }
1446
1447 *num_intersections = intersection_count;
1448 for (e1 = sweep_line.stopped; e1; e1 = e1->next) {
1449 if (e1->deferred_trap.right != NULL((void*)0)) {
1450 _cairo_bo_edge_end_trap (e1, e1->edge.bottom, traps);
1451 }
1452 }
1453 status = traps->status;
1454 unwind:
1455 _cairo_bo_event_queue_fini (&event_queue);
1456
1457#if DEBUG_EVENTS0
1458 event_log ("\n");
1459#endif
1460
1461 return status;
1462}
1463
1464cairo_status_t
1465_cairo_bentley_ottmann_tessellate_polygon (cairo_traps_t *traps,
1466 const cairo_polygon_t *polygon,
1467 cairo_fill_rule_t fill_rule)
1468{
1469 int intersections;
1470 cairo_bo_start_event_t stack_events[CAIRO_STACK_ARRAY_LENGTH (cairo_bo_start_event_t)((512 * sizeof (int)) / sizeof(cairo_bo_start_event_t))];
1471 cairo_bo_start_event_t *events;
1472 cairo_bo_event_t *stack_event_ptrs[ARRAY_LENGTH (stack_events)((int) (sizeof (stack_events) / sizeof (stack_events[0]))) + 1];
1473 cairo_bo_event_t **event_ptrs;
1474 cairo_bo_start_event_t *stack_event_y[64];
1475 cairo_bo_start_event_t **event_y = NULL((void*)0);
1476 int i, num_events, y, ymin, ymax;
1477 cairo_status_t status;
1478
1479 num_events = polygon->num_edges;
1480 if (unlikely (0 == num_events)(__builtin_expect (!!(0 == num_events), 0)))
6
←
Assuming 'num_events' is not equal to 0
→
7
←
Taking false branch
→
1481 return CAIRO_STATUS_SUCCESS;
1482
1483 if (polygon->num_limits) {
8
←
Assuming field 'num_limits' is 0
→
9
←
Taking false branch
→
1484 ymin = _cairo_fixed_integer_floor (polygon->limit.p1.y);
1485 ymax = _cairo_fixed_integer_ceil (polygon->limit.p2.y) - ymin;
1486
1487 if (ymax > 64) {
1488 event_y = _cairo_malloc_ab(sizeof (cairo_bo_event_t*), ymax);
1489 if (unlikely (event_y == NULL)(__builtin_expect (!!(event_y == ((void*)0)), 0)))
1490 return _cairo_error (CAIRO_STATUS_NO_MEMORY);
1491 } else {
1492 event_y = stack_event_y;
1493 }
1494 memset (event_y, 0, ymax * sizeof(cairo_bo_event_t *));
1495 }
1496
1497 events = stack_events;
1498 event_ptrs = stack_event_ptrs;
1499 if (num_events > ARRAY_LENGTH (stack_events)((int) (sizeof (stack_events) / sizeof (stack_events[0])))) {
10
←
Assuming the condition is false
→
11
←
Taking false branch
→
1500 events = _cairo_malloc_ab_plus_c (num_events,
1501 sizeof (cairo_bo_start_event_t) +
1502 sizeof (cairo_bo_event_t *),
1503 sizeof (cairo_bo_event_t *));
1504 if (unlikely (events == NULL)(__builtin_expect (!!(events == ((void*)0)), 0))) {
1505 if (event_y != stack_event_y)
1506 free (event_y);
1507 return _cairo_error (CAIRO_STATUS_NO_MEMORY);
1508 }
1509
1510 event_ptrs = (cairo_bo_event_t **) (events + num_events);
1511 }
1512
1513 for (i = 0; i < num_events; i++) {
12
←
Assuming 'i' is >= 'num_events'
→
13
←
Loop condition is false. Execution continues on line 1534
→
1514 events[i].type = CAIRO_BO_EVENT_TYPE_START;
1515 events[i].point.y = polygon->edges[i].top;
1516 events[i].point.x =
1517 _line_compute_intersection_x_for_y (&polygon->edges[i].line,
1518 events[i].point.y);
1519
1520 events[i].edge.edge = polygon->edges[i];
1521 events[i].edge.deferred_trap.right = NULL((void*)0);
1522 events[i].edge.prev = NULL((void*)0);
1523 events[i].edge.next = NULL((void*)0);
1524 events[i].edge.colinear = NULL((void*)0);
1525
1526 if (event_y) {
1527 y = _cairo_fixed_integer_floor (events[i].point.y) - ymin;
1528 events[i].edge.next = (cairo_bo_edge_t *) event_y[y];
1529 event_y[y] = (cairo_bo_start_event_t *) &events[i];
1530 } else
1531 event_ptrs[i] = (cairo_bo_event_t *) &events[i];
1532 }
1533
1534 if (event_y
13.1
'event_y' is null
) {
14
←
Taking false branch
→
1535 for (y = i = 0; y < ymax && i < num_events; y++) {
1536 cairo_bo_start_event_t *e;
1537 int j = i;
1538 for (e = event_y[y]; e; e = (cairo_bo_start_event_t *)e->edge.next)
1539 event_ptrs[i++] = (cairo_bo_event_t *) e;
1540 if (i > j + 1)
1541 _cairo_bo_event_queue_sort (event_ptrs+j, i-j);
1542 }
1543 if (event_y != stack_event_y)
1544 free (event_y);
1545 } else
1546 _cairo_bo_event_queue_sort (event_ptrs, i);
15
←
Calling '_cairo_bo_event_queue_sort'
→
1547 event_ptrs[i] = NULL((void*)0);
1548
1549#if DEBUG_TRAPS0
1550 dump_edges (events, num_events, "bo-polygon-edges.txt");
1551#endif
1552
1553 /* XXX: This would be the convenient place to throw in multiple
1554 * passes of the Bentley-Ottmann algorithm. It would merely
1555 * require storing the results of each pass into a temporary
1556 * cairo_traps_t. */
1557 status = _cairo_bentley_ottmann_tessellate_bo_edges (event_ptrs, num_events,
1558 fill_rule, traps,
1559 &intersections);
1560#if DEBUG_TRAPS0
1561 dump_traps (traps, "bo-polygon-out.txt");
1562#endif
1563
1564 if (events != stack_events)
1565 free (events);
1566
1567 return status;
1568}
1569
1570cairo_status_t
1571_cairo_bentley_ottmann_tessellate_traps (cairo_traps_t *traps,
1572 cairo_fill_rule_t fill_rule)
1573{
1574 cairo_status_t status;
1575 cairo_polygon_t polygon;
1576 int i;
1577
1578 if (unlikely (0 == traps->num_traps)(__builtin_expect (!!(0 == traps->num_traps), 0)))
1
Assuming 0 is not equal to field 'num_traps'
→
2
←
Taking false branch
→
1579 return CAIRO_STATUS_SUCCESS;
1580
1581#if DEBUG_TRAPS0
1582 dump_traps (traps, "bo-traps-in.txt");
1583#endif
1584
1585 _cairo_polygon_init (&polygon, traps->limits, traps->num_limits);
1586
1587 for (i = 0; i < traps->num_traps; i++) {
3
←
Assuming 'i' is >= field 'num_traps'
→
4
←
Loop condition is false. Execution continues on line 1605
→
1588 status = _cairo_polygon_add_line (&polygon,
1589 &traps->traps[i].left,
1590 traps->traps[i].top,
1591 traps->traps[i].bottom,
1592 1);
1593 if (unlikely (status)(__builtin_expect (!!(status), 0)))
1594 goto CLEANUP;
1595
1596 status = _cairo_polygon_add_line (&polygon,
1597 &traps->traps[i].right,
1598 traps->traps[i].top,
1599 traps->traps[i].bottom,
1600 -1);
1601 if (unlikely (status)(__builtin_expect (!!(status), 0)))
1602 goto CLEANUP;
1603 }
1604
1605 _cairo_traps_clear (traps);
1606 status = _cairo_bentley_ottmann_tessellate_polygon (traps,
5
←
Calling '_cairo_bentley_ottmann_tessellate_polygon'
→
1607 &polygon,
1608 fill_rule);
1609
1610#if DEBUG_TRAPS0
1611 dump_traps (traps, "bo-traps-out.txt");
1612#endif
1613
1614 CLEANUP:
1615 _cairo_polygon_fini (&polygon);
1616
1617 return status;
1618}
1619
1620#if 0
1621static cairo_bool_t
1622edges_have_an_intersection_quadratic (cairo_bo_edge_t *edges,
1623 int num_edges)
1624
1625{
1626 int i, j;
1627 cairo_bo_edge_t *a, *b;
1628 cairo_bo_point32_t intersection;
1629
1630 /* We must not be given any upside-down edges. */
1631 for (i = 0; i < num_edges; i++) {
1632 assert (_cairo_bo_point32_compare (&edges[i].top, &edges[i].bottom) < 0)((void) sizeof ((_cairo_bo_point32_compare (&edges[i].top
, &edges[i].bottom) < 0) ? 1 : 0), __extension__ ({ if
(_cairo_bo_point32_compare (&edges[i].top, &edges[i]
.bottom) < 0) ; else __assert_fail ("_cairo_bo_point32_compare (&edges[i].top, &edges[i].bottom) < 0"
, "/root/firefox-clang/gfx/cairo/cairo/src/cairo-bentley-ottmann.c"
, 1632, __extension__ __PRETTY_FUNCTION__); }));
1633 edges[i].line.p1.x <<= CAIRO_BO_GUARD_BITS;
1634 edges[i].line.p1.y <<= CAIRO_BO_GUARD_BITS;
1635 edges[i].line.p2.x <<= CAIRO_BO_GUARD_BITS;
1636 edges[i].line.p2.y <<= CAIRO_BO_GUARD_BITS;
1637 }
1638
1639 for (i = 0; i < num_edges; i++) {
1640 for (j = 0; j < num_edges; j++) {
1641 if (i == j)
1642 continue;
1643
1644 a = &edges[i];
1645 b = &edges[j];
1646
1647 if (! _cairo_bo_edge_intersect (a, b, &intersection))
1648 continue;
1649
1650 printf ("Found intersection (%d,%d) between (%d,%d)-(%d,%d) and (%d,%d)-(%d,%d)\n",
1651 intersection.x,
1652 intersection.y,
1653 a->line.p1.x, a->line.p1.y,
1654 a->line.p2.x, a->line.p2.y,
1655 b->line.p1.x, b->line.p1.y,
1656 b->line.p2.x, b->line.p2.y);
1657
1658 return TRUE1;
1659 }
1660 }
1661 return FALSE0;
1662}
1663
1664#define TEST_MAX_EDGES 10
1665
1666typedef struct test {
1667 const char *name;
1668 const char *description;
1669 int num_edges;
1670 cairo_bo_edge_t edges[TEST_MAX_EDGES];
1671} test_t;
1672
1673static test_t
1674tests[] = {
1675 {
1676 "3 near misses",
1677 "3 edges all intersecting very close to each other",
1678 3,
1679 {
1680 { { 4, 2}, {0, 0}, { 9, 9}, NULL((void*)0), NULL((void*)0) },
1681 { { 7, 2}, {0, 0}, { 2, 3}, NULL((void*)0), NULL((void*)0) },
1682 { { 5, 2}, {0, 0}, { 1, 7}, NULL((void*)0), NULL((void*)0) }
1683 }
1684 },
1685 {
1686 "inconsistent data",
1687 "Derived from random testing---was leading to skip list and edge list disagreeing.",
1688 2,
1689 {
1690 { { 2, 3}, {0, 0}, { 8, 9}, NULL((void*)0), NULL((void*)0) },
1691 { { 2, 3}, {0, 0}, { 6, 7}, NULL((void*)0), NULL((void*)0) }
1692 }
1693 },
1694 {
1695 "failed sort",
1696 "A test derived from random testing that leads to an inconsistent sort --- looks like we just can't attempt to validate the sweep line with edge_compare?",
1697 3,
1698 {
1699 { { 6, 2}, {0, 0}, { 6, 5}, NULL((void*)0), NULL((void*)0) },
1700 { { 3, 5}, {0, 0}, { 5, 6}, NULL((void*)0), NULL((void*)0) },
1701 { { 9, 2}, {0, 0}, { 5, 6}, NULL((void*)0), NULL((void*)0) },
1702 }
1703 },
1704 {
1705 "minimal-intersection",
1706 "Intersection of a two from among the smallest possible edges.",
1707 2,
1708 {
1709 { { 0, 0}, {0, 0}, { 1, 1}, NULL((void*)0), NULL((void*)0) },
1710 { { 1, 0}, {0, 0}, { 0, 1}, NULL((void*)0), NULL((void*)0) }
1711 }
1712 },
1713 {
1714 "simple",
1715 "A simple intersection of two edges at an integer (2,2).",
1716 2,
1717 {
1718 { { 1, 1}, {0, 0}, { 3, 3}, NULL((void*)0), NULL((void*)0) },
1719 { { 2, 1}, {0, 0}, { 2, 3}, NULL((void*)0), NULL((void*)0) }
1720 }
1721 },
1722 {
1723 "bend-to-horizontal",
1724 "With intersection truncation one edge bends to horizontal",
1725 2,
1726 {
1727 { { 9, 1}, {0, 0}, {3, 7}, NULL((void*)0), NULL((void*)0) },
1728 { { 3, 5}, {0, 0}, {9, 9}, NULL((void*)0), NULL((void*)0) }
1729 }
1730 }
1731};
1732
1733/*
1734 {
1735 "endpoint",
1736 "An intersection that occurs at the endpoint of a segment.",
1737 {
1738 { { 4, 6}, { 5, 6}, NULL, { { NULL }} },
1739 { { 4, 5}, { 5, 7}, NULL, { { NULL }} },
1740 { { 0, 0}, { 0, 0}, NULL, { { NULL }} },
1741 }
1742 }
1743 {
1744 name = "overlapping",
1745 desc = "Parallel segments that share an endpoint, with different slopes.",
1746 edges = {
1747 { top = { x = 2, y = 0}, bottom = { x = 1, y = 1}},
1748 { top = { x = 2, y = 0}, bottom = { x = 0, y = 2}},
1749 { top = { x = 0, y = 3}, bottom = { x = 1, y = 3}},
1750 { top = { x = 0, y = 3}, bottom = { x = 2, y = 3}},
1751 { top = { x = 0, y = 4}, bottom = { x = 0, y = 6}},
1752 { top = { x = 0, y = 5}, bottom = { x = 0, y = 6}}
1753 }
1754 },
1755 {
1756 name = "hobby_stage_3",
1757 desc = "A particularly tricky part of the 3rd stage of the 'hobby' test below.",
1758 edges = {
1759 { top = { x = -1, y = -2}, bottom = { x = 4, y = 2}},
1760 { top = { x = 5, y = 3}, bottom = { x = 9, y = 5}},
1761 { top = { x = 5, y = 3}, bottom = { x = 6, y = 3}},
1762 }
1763 },
1764 {
1765 name = "hobby",
1766 desc = "Example from John Hobby's paper. Requires 3 passes of the iterative algorithm.",
1767 edges = {
1768 { top = { x = 0, y = 0}, bottom = { x = 9, y = 5}},
1769 { top = { x = 0, y = 0}, bottom = { x = 13, y = 6}},
1770 { top = { x = -1, y = -2}, bottom = { x = 9, y = 5}}
1771 }
1772 },
1773 {
1774 name = "slope",
1775 desc = "Edges with same start/stop points but different slopes",
1776 edges = {
1777 { top = { x = 4, y = 1}, bottom = { x = 6, y = 3}},
1778 { top = { x = 4, y = 1}, bottom = { x = 2, y = 3}},
1779 { top = { x = 2, y = 4}, bottom = { x = 4, y = 6}},
1780 { top = { x = 6, y = 4}, bottom = { x = 4, y = 6}}
1781 }
1782 },
1783 {
1784 name = "horizontal",
1785 desc = "Test of a horizontal edge",
1786 edges = {
1787 { top = { x = 1, y = 1}, bottom = { x = 6, y = 6}},
1788 { top = { x = 2, y = 3}, bottom = { x = 5, y = 3}}
1789 }
1790 },
1791 {
1792 name = "vertical",
1793 desc = "Test of a vertical edge",
1794 edges = {
1795 { top = { x = 5, y = 1}, bottom = { x = 5, y = 7}},
1796 { top = { x = 2, y = 4}, bottom = { x = 8, y = 5}}
1797 }
1798 },
1799 {
1800 name = "congruent",
1801 desc = "Two overlapping edges with the same slope",
1802 edges = {
1803 { top = { x = 5, y = 1}, bottom = { x = 5, y = 7}},
1804 { top = { x = 5, y = 2}, bottom = { x = 5, y = 6}},
1805 { top = { x = 2, y = 4}, bottom = { x = 8, y = 5}}
1806 }
1807 },
1808 {
1809 name = "multi",
1810 desc = "Several segments with a common intersection point",
1811 edges = {
1812 { top = { x = 1, y = 2}, bottom = { x = 5, y = 4} },
1813 { top = { x = 1, y = 1}, bottom = { x = 5, y = 5} },
1814 { top = { x = 2, y = 1}, bottom = { x = 4, y = 5} },
1815 { top = { x = 4, y = 1}, bottom = { x = 2, y = 5} },
1816 { top = { x = 5, y = 1}, bottom = { x = 1, y = 5} },
1817 { top = { x = 5, y = 2}, bottom = { x = 1, y = 4} }
1818 }
1819 }
1820};
1821*/
1822
1823static int
1824run_test (const char *test_name,
1825 cairo_bo_edge_t *test_edges,
1826 int num_edges)
1827{
1828 int i, intersections, passes;
1829 cairo_bo_edge_t *edges;
1830 cairo_array_t intersected_edges;
1831
1832 printf ("Testing: %s\n", test_name);
1833
1834 _cairo_array_init (&intersected_edges, sizeof (cairo_bo_edge_t));
1835
1836 intersections = _cairo_bentley_ottmann_intersect_edges (test_edges, num_edges, &intersected_edges);
1837 if (intersections)
1838 printf ("Pass 1 found %d intersections:\n", intersections);
1839
1840
1841 /* XXX: Multi-pass Bentley-Ottmmann. Preferable would be to add a
1842 * pass of Hobby's tolerance-square algorithm instead. */
1843 passes = 1;
1844 while (intersections) {
1845 int num_edges = _cairo_array_num_elements (&intersected_edges);
1846 passes++;
1847 edges = _cairo_malloc_ab (num_edges, sizeof (cairo_bo_edge_t));
1848 assert (edges != NULL)((void) sizeof ((edges != ((void*)0)) ? 1 : 0), __extension__
({ if (edges != ((void*)0)) ; else __assert_fail ("edges != NULL"
, "/root/firefox-clang/gfx/cairo/cairo/src/cairo-bentley-ottmann.c"
, 1848, __extension__ __PRETTY_FUNCTION__); }));
1849 memcpy (edges, _cairo_array_index (&intersected_edges, 0), num_edges * sizeof (cairo_bo_edge_t));
1850 _cairo_array_fini (&intersected_edges);
1851 _cairo_array_init (&intersected_edges, sizeof (cairo_bo_edge_t));
1852 intersections = _cairo_bentley_ottmann_intersect_edges (edges, num_edges, &intersected_edges);
1853 free (edges);
1854
1855 if (intersections){
1856 printf ("Pass %d found %d remaining intersections:\n", passes, intersections);
1857 } else {
1858 if (passes > 3)
1859 for (i = 0; i < passes; i++)
1860 printf ("*");
1861 printf ("No remainining intersections found after pass %d\n", passes);
1862 }
1863 }
1864
1865 if (edges_have_an_intersection_quadratic (_cairo_array_index (&intersected_edges, 0),
1866 _cairo_array_num_elements (&intersected_edges)))
1867 printf ("*** FAIL ***\n");
1868 else
1869 printf ("PASS\n");
1870
1871 _cairo_array_fini (&intersected_edges);
1872
1873 return 0;
1874}
1875
1876#define MAX_RANDOM 300
1877
1878int
1879main (void)
1880{
1881 char random_name[] = "random-XX";
1882 cairo_bo_edge_t random_edges[MAX_RANDOM], *edge;
1883 unsigned int i, num_random;
1884 test_t *test;
1885
1886 for (i = 0; i < ARRAY_LENGTH (tests)((int) (sizeof (tests) / sizeof (tests[0]))); i++) {
1887 test = &tests[i];
1888 run_test (test->name, test->edges, test->num_edges);
1889 }
1890
1891 for (num_random = 0; num_random < MAX_RANDOM; num_random++) {
1892 srand (0);
1893 for (i = 0; i < num_random; i++) {
1894 do {
1895 edge = &random_edges[i];
1896 edge->line.p1.x = (int32_t) (10.0 * (rand() / (RAND_MAX2147483647 + 1.0)));
1897 edge->line.p1.y = (int32_t) (10.0 * (rand() / (RAND_MAX2147483647 + 1.0)));
1898 edge->line.p2.x = (int32_t) (10.0 * (rand() / (RAND_MAX2147483647 + 1.0)));
1899 edge->line.p2.y = (int32_t) (10.0 * (rand() / (RAND_MAX2147483647 + 1.0)));
1900 if (edge->line.p1.y > edge->line.p2.y) {
1901 int32_t tmp = edge->line.p1.y;
1902 edge->line.p1.y = edge->line.p2.y;
1903 edge->line.p2.y = tmp;
1904 }
1905 } while (edge->line.p1.y == edge->line.p2.y);
1906 }
1907
1908 sprintf (random_name, "random-%02d", num_random);
1909
1910 run_test (random_name, random_edges, num_random);
1911 }
1912
1913 return 0;
1914}
1915#endif