Bug Summary

File:src/Region.c
Location:line 539, column 2
Description:Null pointer passed as an argument to a 'nonnull' parameter

Annotated Source Code

1/************************************************************************
2
3Copyright 1987, 1988, 1998 The Open Group
4
5Permission to use, copy, modify, distribute, and sell this software and its
6documentation for any purpose is hereby granted without fee, provided that
7the above copyright notice appear in all copies and that both that
8copyright notice and this permission notice appear in supporting
9documentation.
10
11The above copyright notice and this permission notice shall be included in
12all copies or substantial portions of the Software.
13
14THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
17OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
18AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
19CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
20
21Except as contained in this notice, the name of The Open Group shall not be
22used in advertising or otherwise to promote the sale, use or other dealings
23in this Software without prior written authorization from The Open Group.
24
25
26Copyright 1987, 1988 by Digital Equipment Corporation, Maynard, Massachusetts.
27
28 All Rights Reserved
29
30Permission to use, copy, modify, and distribute this software and its
31documentation for any purpose and without fee is hereby granted,
32provided that the above copyright notice appear in all copies and that
33both that copyright notice and this permission notice appear in
34supporting documentation, and that the name of Digital not be
35used in advertising or publicity pertaining to distribution of the
36software without specific, written prior permission.
37
38DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
39ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
40DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
41ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
42WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
43ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
44SOFTWARE.
45
46************************************************************************/
47/*
48 * The functions in this file implement the Region abstraction, similar to one
49 * used in the X11 sample server. A Region is simply an area, as the name
50 * implies, and is implemented as a "y-x-banded" array of rectangles. To
51 * explain: Each Region is made up of a certain number of rectangles sorted
52 * by y coordinate first, and then by x coordinate.
53 *
54 * Furthermore, the rectangles are banded such that every rectangle with a
55 * given upper-left y coordinate (y1) will have the same lower-right y
56 * coordinate (y2) and vice versa. If a rectangle has scanlines in a band, it
57 * will span the entire vertical distance of the band. This means that some
58 * areas that could be merged into a taller rectangle will be represented as
59 * several shorter rectangles to account for shorter rectangles to its left
60 * or right but within its "vertical scope".
61 *
62 * An added constraint on the rectangles is that they must cover as much
63 * horizontal area as possible. E.g. no two rectangles in a band are allowed
64 * to touch.
65 *
66 * Whenever possible, bands will be merged together to cover a greater vertical
67 * distance (and thus reduce the number of rectangles). Two bands can be merged
68 * only if the bottom of one touches the top of the other and they have
69 * rectangles in the same places (of the same width, of course). This maintains
70 * the y-x-banding that's so nice to have...
71 */
72
73#ifdef HAVE_CONFIG_H1
74#include <config.h>
75#endif
76#include "Xlibint.h"
77#include "Xutil.h"
78#include <X11/Xregion.h>
79#include "poly.h"
80
81#ifdef DEBUG
82#include <stdio.h>
83#define assert(expr) {if (!(expr)) fprintf(stderr,\
84"Assertion failed file %s, line %d: expr\n", __FILE__"Region.c", __LINE__84); }
85#else
86#define assert(expr)
87#endif
88
89typedef int (*overlapProcp)(
90 register Region pReg,
91 register BoxPtr r1,
92 BoxPtr r1End,
93 register BoxPtr r2,
94 BoxPtr r2End,
95 short y1,
96 short y2);
97
98typedef int (*nonOverlapProcp)(
99 register Region pReg,
100 register BoxPtr r,
101 BoxPtr rEnd,
102 register short y1,
103 register short y2);
104
105static void miRegionOp(
106 register Region newReg, /* Place to store result */
107 Region reg1, /* First region in operation */
108 Region reg2, /* 2d region in operation */
109 int (*overlapFunc)(
110 register Region pReg,
111 register BoxPtr r1,
112 BoxPtr r1End,
113 register BoxPtr r2,
114 BoxPtr r2End,
115 short y1,
116 short y2), /* Function to call for over-
117 * lapping bands */
118 int (*nonOverlap1Func)(
119 register Region pReg,
120 register BoxPtr r,
121 BoxPtr rEnd,
122 register short y1,
123 register short y2), /* Function to call for non-
124 * overlapping bands in region
125 * 1 */
126 int (*nonOverlap2Func)(
127 register Region pReg,
128 register BoxPtr r,
129 BoxPtr rEnd,
130 register short y1,
131 register short y2)); /* Function to call for non-
132 * overlapping bands in region
133 * 2 */
134
135
136/* Create a new empty region */
137Region
138XCreateRegion(void)
139{
140 Region temp;
141
142 if (! (temp = ( Region )Xmalloc( (unsigned) sizeof( REGION ))malloc((((unsigned) sizeof( REGION )) == 0 ? 1 : ((unsigned) sizeof
( REGION ))))
))
143 return (Region) NULL((void*)0);
144 if (! (temp->rects = ( BOX * )Xmalloc( (unsigned) sizeof( BOX ))malloc((((unsigned) sizeof( BOX )) == 0 ? 1 : ((unsigned) sizeof
( BOX ))))
)) {
145 Xfree((char *) temp)free(((char *) temp));
146 return (Region) NULL((void*)0);
147 }
148 temp->numRects = 0;
149 temp->extents.x1 = 0;
150 temp->extents.y1 = 0;
151 temp->extents.x2 = 0;
152 temp->extents.y2 = 0;
153 temp->size = 1;
154 return( temp );
155}
156
157int
158XClipBox(
159 Region r,
160 XRectangle *rect)
161{
162 rect->x = r->extents.x1;
163 rect->y = r->extents.y1;
164 rect->width = r->extents.x2 - r->extents.x1;
165 rect->height = r->extents.y2 - r->extents.y1;
166 return 1;
167}
168
169int
170XUnionRectWithRegion(
171 register XRectangle *rect,
172 Region source, Region dest)
173{
174 REGION region;
175
176 if (!rect->width || !rect->height)
177 return 0;
178 region.rects = &region.extents;
179 region.numRects = 1;
180 region.extents.x1 = rect->x;
181 region.extents.y1 = rect->y;
182 region.extents.x2 = rect->x + rect->width;
183 region.extents.y2 = rect->y + rect->height;
184 region.size = 1;
185
186 return XUnionRegion(&region, source, dest);
187}
188
189/*-
190 *-----------------------------------------------------------------------
191 * miSetExtents --
192 * Reset the extents of a region to what they should be. Called by
193 * miSubtract and miIntersect b/c they can't figure it out along the
194 * way or do so easily, as miUnion can.
195 *
196 * Results:
197 * None.
198 *
199 * Side Effects:
200 * The region's 'extents' structure is overwritten.
201 *
202 *-----------------------------------------------------------------------
203 */
204static void
205miSetExtents (
206 Region pReg)
207{
208 register BoxPtr pBox,
209 pBoxEnd,
210 pExtents;
211
212 if (pReg->numRects == 0)
213 {
214 pReg->extents.x1 = 0;
215 pReg->extents.y1 = 0;
216 pReg->extents.x2 = 0;
217 pReg->extents.y2 = 0;
218 return;
219 }
220
221 pExtents = &pReg->extents;
222 pBox = pReg->rects;
223 pBoxEnd = &pBox[pReg->numRects - 1];
224
225 /*
226 * Since pBox is the first rectangle in the region, it must have the
227 * smallest y1 and since pBoxEnd is the last rectangle in the region,
228 * it must have the largest y2, because of banding. Initialize x1 and
229 * x2 from pBox and pBoxEnd, resp., as good things to initialize them
230 * to...
231 */
232 pExtents->x1 = pBox->x1;
233 pExtents->y1 = pBox->y1;
234 pExtents->x2 = pBoxEnd->x2;
235 pExtents->y2 = pBoxEnd->y2;
236
237 assert(pExtents->y1 < pExtents->y2);
238 while (pBox <= pBoxEnd)
239 {
240 if (pBox->x1 < pExtents->x1)
241 {
242 pExtents->x1 = pBox->x1;
243 }
244 if (pBox->x2 > pExtents->x2)
245 {
246 pExtents->x2 = pBox->x2;
247 }
248 pBox++;
249 }
250 assert(pExtents->x1 < pExtents->x2);
251}
252
253int
254XSetRegion(
255 Display *dpy,
256 GC gc,
257 register Region r)
258{
259 register int i;
260 register XRectangle *xr, *pr;
261 register BOX *pb;
262 unsigned long total;
263
264 LockDisplay (dpy)if ((dpy)->lock_fns) (*(dpy)->lock_fns->lock_display
)(dpy)
;
265 total = r->numRects * sizeof (XRectangle);
266 if ((xr = (XRectangle *) _XAllocTemp(dpy, total))) {
267 for (pr = xr, pb = r->rects, i = r->numRects; --i >= 0; pr++, pb++) {
268 pr->x = pb->x1;
269 pr->y = pb->y1;
270 pr->width = pb->x2 - pb->x1;
271 pr->height = pb->y2 - pb->y1;
272 }
273 }
274 if (xr || !r->numRects)
275 _XSetClipRectangles(dpy, gc, 0, 0, xr, r->numRects, YXBanded3);
276 if (xr)
277 _XFreeTemp(dpy, (char *)xr, total);
278 UnlockDisplay(dpy)if ((dpy)->lock_fns) (*(dpy)->lock_fns->unlock_display
)(dpy)
;
279 SyncHandle()if (dpy->synchandler) (*dpy->synchandler)(dpy);
280 return 1;
281}
282
283int
284XDestroyRegion(
285 Region r)
286{
287 Xfree( (char *) r->rects )free(((char *) r->rects));
288 Xfree( (char *) r )free(((char *) r));
289 return 1;
290}
291
292
293/* TranslateRegion(pRegion, x, y)
294 translates in place
295 added by raymond
296*/
297
298int
299XOffsetRegion(
300 register Region pRegion,
301 register int x,
302 register int y)
303{
304 register int nbox;
305 register BOX *pbox;
306
307 pbox = pRegion->rects;
308 nbox = pRegion->numRects;
309
310 while(nbox--)
311 {
312 pbox->x1 += x;
313 pbox->x2 += x;
314 pbox->y1 += y;
315 pbox->y2 += y;
316 pbox++;
317 }
318 pRegion->extents.x1 += x;
319 pRegion->extents.x2 += x;
320 pRegion->extents.y1 += y;
321 pRegion->extents.y2 += y;
322 return 1;
323}
324
325/*
326 Utility procedure Compress:
327 Replace r by the region r', where
328 p in r' iff (Quantifer m <= dx) (p + m in r), and
329 Quantifier is Exists if grow is TRUE, For all if grow is FALSE, and
330 (x,y) + m = (x+m,y) if xdir is TRUE; (x,y+m) if xdir is FALSE.
331
332 Thus, if xdir is TRUE and grow is FALSE, r is replaced by the region
333 of all points p such that p and the next dx points on the same
334 horizontal scan line are all in r. We do this using by noting
335 that p is the head of a run of length 2^i + k iff p is the head
336 of a run of length 2^i and p+2^i is the head of a run of length
337 k. Thus, the loop invariant: s contains the region corresponding
338 to the runs of length shift. r contains the region corresponding
339 to the runs of length 1 + dxo & (shift-1), where dxo is the original
340 value of dx. dx = dxo & ~(shift-1). As parameters, s and t are
341 scratch regions, so that we don't have to allocate them on every
342 call.
343*/
344
345#define ZOpRegion(a,b,c) if (grow) XUnionRegion(a,b,c); \
346 else XIntersectRegion(a,b,c)
347#define ZShiftRegion(a,b) if (xdir) XOffsetRegion(a,b,0); \
348 else XOffsetRegion(a,0,b)
349#define ZCopyRegion(a,b) XUnionRegion(a,a,b)
350
351static void
352Compress(
353 Region r, Region s, Region t,
354 register unsigned dx,
355 register int xdir, register int grow)
356{
357 register unsigned shift = 1;
358
359 ZCopyRegion(r, s);
360 while (dx) {
361 if (dx & shift) {
362 ZShiftRegion(r, -(int)shift);
363 ZOpRegion(r, s, r);
364 dx -= shift;
365 if (!dx) break;
366 }
367 ZCopyRegion(s, t);
368 ZShiftRegion(s, -(int)shift);
369 ZOpRegion(s, t, s);
370 shift <<= 1;
371 }
372}
373
374#undef ZOpRegion
375#undef ZShiftRegion
376#undef ZCopyRegion
377
378int
379XShrinkRegion(
380 Region r,
381 int dx, int dy)
382{
383 Region s, t;
384 int grow;
385
386 if (!dx && !dy) return 0;
387 if (! (s = XCreateRegion()) )
388 return 0;
389 if (! (t = XCreateRegion()) ) {
390 XDestroyRegion(s);
391 return 0;
392 }
393 if ((grow = (dx < 0))) dx = -dx;
394 if (dx) Compress(r, s, t, (unsigned) 2*dx, TRUE1, grow);
395 if ((grow = (dy < 0))) dy = -dy;
396 if (dy) Compress(r, s, t, (unsigned) 2*dy, FALSE0, grow);
397 XOffsetRegion(r, dx, dy);
398 XDestroyRegion(s);
399 XDestroyRegion(t);
400 return 0;
401}
402
403
404/*======================================================================
405 * Region Intersection
406 *====================================================================*/
407/*-
408 *-----------------------------------------------------------------------
409 * miIntersectO --
410 * Handle an overlapping band for miIntersect.
411 *
412 * Results:
413 * None.
414 *
415 * Side Effects:
416 * Rectangles may be added to the region.
417 *
418 *-----------------------------------------------------------------------
419 */
420/* static void*/
421static int
422miIntersectO (
423 register Region pReg,
424 register BoxPtr r1,
425 BoxPtr r1End,
426 register BoxPtr r2,
427 BoxPtr r2End,
428 short y1,
429 short y2)
430{
431 register short x1;
432 register short x2;
433 register BoxPtr pNextRect;
434
435 pNextRect = &pReg->rects[pReg->numRects];
436
437 while ((r1 != r1End) && (r2 != r2End))
438 {
439 x1 = max(r1->x1,r2->x1)(((r1->x1) > (r2->x1)) ? (r1->x1) : (r2->x1));
440 x2 = min(r1->x2,r2->x2)(((r1->x2) < (r2->x2)) ? (r1->x2) : (r2->x2));
441
442 /*
443 * If there's any overlap between the two rectangles, add that
444 * overlap to the new region.
445 * There's no need to check for subsumption because the only way
446 * such a need could arise is if some region has two rectangles
447 * right next to each other. Since that should never happen...
448 */
449 if (x1 < x2)
450 {
451 assert(y1<y2);
452
453 MEMCHECK(pReg, pNextRect, pReg->rects){ if ((pReg)->numRects >= ((pReg)->size - 1)){ (pReg
->rects) = (BOX *) realloc(((char *)(pReg->rects)), (((
unsigned) (2 * (sizeof(BOX)) * ((pReg)->size))) == 0 ? 1 :
((unsigned) (2 * (sizeof(BOX)) * ((pReg)->size))))); if (
(pReg->rects) == 0) return(0); (pReg)->size *= 2; (pNextRect
) = &(pReg->rects)[(pReg)->numRects]; } }
;
454 pNextRect->x1 = x1;
455 pNextRect->y1 = y1;
456 pNextRect->x2 = x2;
457 pNextRect->y2 = y2;
458 pReg->numRects += 1;
459 pNextRect++;
460 assert(pReg->numRects <= pReg->size);
461 }
462
463 /*
464 * Need to advance the pointers. Shift the one that extends
465 * to the right the least, since the other still has a chance to
466 * overlap with that region's next rectangle, if you see what I mean.
467 */
468 if (r1->x2 < r2->x2)
469 {
470 r1++;
471 }
472 else if (r2->x2 < r1->x2)
473 {
474 r2++;
475 }
476 else
477 {
478 r1++;
479 r2++;
480 }
481 }
482 return 0; /* lint */
483}
484
485int
486XIntersectRegion(
487 Region reg1,
488 Region reg2, /* source regions */
489 register Region newReg) /* destination Region */
490{
491 /* check for trivial reject */
492 if ( (!(reg1->numRects)) || (!(reg2->numRects)) ||
493 (!EXTENTCHECK(&reg1->extents, &reg2->extents)((&reg1->extents)->x2 > (&reg2->extents)->
x1 && (&reg1->extents)->x1 < (&reg2->
extents)->x2 && (&reg1->extents)->y2 >
(&reg2->extents)->y1 && (&reg1->extents
)->y1 < (&reg2->extents)->y2)
))
494 newReg->numRects = 0;
495 else
496 miRegionOp (newReg, reg1, reg2,
497 miIntersectO, NULL((void*)0), NULL((void*)0));
498
499 /*
500 * Can't alter newReg's extents before we call miRegionOp because
501 * it might be one of the source regions and miRegionOp depends
502 * on the extents of those regions being the same. Besides, this
503 * way there's no checking against rectangles that will be nuked
504 * due to coalescing, so we have to examine fewer rectangles.
505 */
506 miSetExtents(newReg);
507 return 1;
508}
509
510static void
511miRegionCopy(
512 register Region dstrgn,
513 register Region rgn)
514
515{
516 if (dstrgn != rgn) /* don't want to copy to itself */
1
Taking true branch
517 {
518 if (dstrgn->size < rgn->numRects)
2
Taking true branch
519 {
520 if (dstrgn->rects)
3
Taking false branch
521 {
522 BOX *prevRects = dstrgn->rects;
523
524 if (! (dstrgn->rects = (BOX *)
525 Xrealloc((char *) dstrgn->rects,realloc(((char *) dstrgn->rects), (((unsigned) rgn->numRects
* (sizeof(BOX))) == 0 ? 1 : ((unsigned) rgn->numRects * (
sizeof(BOX)))))
526 (unsigned) rgn->numRects * (sizeof(BOX)))realloc(((char *) dstrgn->rects), (((unsigned) rgn->numRects
* (sizeof(BOX))) == 0 ? 1 : ((unsigned) rgn->numRects * (
sizeof(BOX)))))
)) {
527 Xfree(prevRects)free((prevRects));
528 return;
529 }
530 }
531 dstrgn->size = rgn->numRects;
532 }
533 dstrgn->numRects = rgn->numRects;
534 dstrgn->extents.x1 = rgn->extents.x1;
535 dstrgn->extents.y1 = rgn->extents.y1;
536 dstrgn->extents.x2 = rgn->extents.x2;
537 dstrgn->extents.y2 = rgn->extents.y2;
538
539 memcpy((char *) dstrgn->rects, (char *) rgn->rects,
4
Null pointer passed as an argument to a 'nonnull' parameter
540 (int) (rgn->numRects * sizeof(BOX)));
541 }
542}
543
544/*======================================================================
545 * Generic Region Operator
546 *====================================================================*/
547
548/*-
549 *-----------------------------------------------------------------------
550 * miCoalesce --
551 * Attempt to merge the boxes in the current band with those in the
552 * previous one. Used only by miRegionOp.
553 *
554 * Results:
555 * The new index for the previous band.
556 *
557 * Side Effects:
558 * If coalescing takes place:
559 * - rectangles in the previous band will have their y2 fields
560 * altered.
561 * - pReg->numRects will be decreased.
562 *
563 *-----------------------------------------------------------------------
564 */
565/* static int*/
566static int
567miCoalesce(
568 register Region pReg, /* Region to coalesce */
569 int prevStart, /* Index of start of previous band */
570 int curStart) /* Index of start of current band */
571{
572 register BoxPtr pPrevBox; /* Current box in previous band */
573 register BoxPtr pCurBox; /* Current box in current band */
574 register BoxPtr pRegEnd; /* End of region */
575 int curNumRects; /* Number of rectangles in current
576 * band */
577 int prevNumRects; /* Number of rectangles in previous
578 * band */
579 int bandY1; /* Y1 coordinate for current band */
580
581 pRegEnd = &pReg->rects[pReg->numRects];
582
583 pPrevBox = &pReg->rects[prevStart];
584 prevNumRects = curStart - prevStart;
585
586 /*
587 * Figure out how many rectangles are in the current band. Have to do
588 * this because multiple bands could have been added in miRegionOp
589 * at the end when one region has been exhausted.
590 */
591 pCurBox = &pReg->rects[curStart];
592 bandY1 = pCurBox->y1;
593 for (curNumRects = 0;
594 (pCurBox != pRegEnd) && (pCurBox->y1 == bandY1);
595 curNumRects++)
596 {
597 pCurBox++;
598 }
599
600 if (pCurBox != pRegEnd)
601 {
602 /*
603 * If more than one band was added, we have to find the start
604 * of the last band added so the next coalescing job can start
605 * at the right place... (given when multiple bands are added,
606 * this may be pointless -- see above).
607 */
608 pRegEnd--;
609 while (pRegEnd[-1].y1 == pRegEnd->y1)
610 {
611 pRegEnd--;
612 }
613 curStart = pRegEnd - pReg->rects;
614 pRegEnd = pReg->rects + pReg->numRects;
615 }
616
617 if ((curNumRects == prevNumRects) && (curNumRects != 0)) {
618 pCurBox -= curNumRects;
619 /*
620 * The bands may only be coalesced if the bottom of the previous
621 * matches the top scanline of the current.
622 */
623 if (pPrevBox->y2 == pCurBox->y1)
624 {
625 /*
626 * Make sure the bands have boxes in the same places. This
627 * assumes that boxes have been added in such a way that they
628 * cover the most area possible. I.e. two boxes in a band must
629 * have some horizontal space between them.
630 */
631 do
632 {
633 if ((pPrevBox->x1 != pCurBox->x1) ||
634 (pPrevBox->x2 != pCurBox->x2))
635 {
636 /*
637 * The bands don't line up so they can't be coalesced.
638 */
639 return (curStart);
640 }
641 pPrevBox++;
642 pCurBox++;
643 prevNumRects -= 1;
644 } while (prevNumRects != 0);
645
646 pReg->numRects -= curNumRects;
647 pCurBox -= curNumRects;
648 pPrevBox -= curNumRects;
649
650 /*
651 * The bands may be merged, so set the bottom y of each box
652 * in the previous band to that of the corresponding box in
653 * the current band.
654 */
655 do
656 {
657 pPrevBox->y2 = pCurBox->y2;
658 pPrevBox++;
659 pCurBox++;
660 curNumRects -= 1;
661 } while (curNumRects != 0);
662
663 /*
664 * If only one band was added to the region, we have to backup
665 * curStart to the start of the previous band.
666 *
667 * If more than one band was added to the region, copy the
668 * other bands down. The assumption here is that the other bands
669 * came from the same region as the current one and no further
670 * coalescing can be done on them since it's all been done
671 * already... curStart is already in the right place.
672 */
673 if (pCurBox == pRegEnd)
674 {
675 curStart = prevStart;
676 }
677 else
678 {
679 do
680 {
681 *pPrevBox++ = *pCurBox++;
682 } while (pCurBox != pRegEnd);
683 }
684
685 }
686 }
687 return (curStart);
688}
689
690/*-
691 *-----------------------------------------------------------------------
692 * miRegionOp --
693 * Apply an operation to two regions. Called by miUnion, miInverse,
694 * miSubtract, miIntersect...
695 *
696 * Results:
697 * None.
698 *
699 * Side Effects:
700 * The new region is overwritten.
701 *
702 * Notes:
703 * The idea behind this function is to view the two regions as sets.
704 * Together they cover a rectangle of area that this function divides
705 * into horizontal bands where points are covered only by one region
706 * or by both. For the first case, the nonOverlapFunc is called with
707 * each the band and the band's upper and lower extents. For the
708 * second, the overlapFunc is called to process the entire band. It
709 * is responsible for clipping the rectangles in the band, though
710 * this function provides the boundaries.
711 * At the end of each band, the new region is coalesced, if possible,
712 * to reduce the number of rectangles in the region.
713 *
714 *-----------------------------------------------------------------------
715 */
716/* static void*/
717static void
718miRegionOp(
719 register Region newReg, /* Place to store result */
720 Region reg1, /* First region in operation */
721 Region reg2, /* 2d region in operation */
722 int (*overlapFunc)(
723 register Region pReg,
724 register BoxPtr r1,
725 BoxPtr r1End,
726 register BoxPtr r2,
727 BoxPtr r2End,
728 short y1,
729 short y2), /* Function to call for over-
730 * lapping bands */
731 int (*nonOverlap1Func)(
732 register Region pReg,
733 register BoxPtr r,
734 BoxPtr rEnd,
735 register short y1,
736 register short y2), /* Function to call for non-
737 * overlapping bands in region
738 * 1 */
739 int (*nonOverlap2Func)(
740 register Region pReg,
741 register BoxPtr r,
742 BoxPtr rEnd,
743 register short y1,
744 register short y2)) /* Function to call for non-
745 * overlapping bands in region
746 * 2 */
747{
748 register BoxPtr r1; /* Pointer into first region */
749 register BoxPtr r2; /* Pointer into 2d region */
750 BoxPtr r1End; /* End of 1st region */
751 BoxPtr r2End; /* End of 2d region */
752 register short ybot; /* Bottom of intersection */
753 register short ytop; /* Top of intersection */
754 BoxPtr oldRects; /* Old rects for newReg */
755 int prevBand; /* Index of start of
756 * previous band in newReg */
757 int curBand; /* Index of start of current
758 * band in newReg */
759 register BoxPtr r1BandEnd; /* End of current band in r1 */
760 register BoxPtr r2BandEnd; /* End of current band in r2 */
761 short top; /* Top of non-overlapping
762 * band */
763 short bot; /* Bottom of non-overlapping
764 * band */
765
766 /*
767 * Initialization:
768 * set r1, r2, r1End and r2End appropriately, preserve the important
769 * parts of the destination region until the end in case it's one of
770 * the two source regions, then mark the "new" region empty, allocating
771 * another array of rectangles for it to use.
772 */
773 r1 = reg1->rects;
774 r2 = reg2->rects;
775 r1End = r1 + reg1->numRects;
776 r2End = r2 + reg2->numRects;
777
778 oldRects = newReg->rects;
779
780 EMPTY_REGION(newReg)newReg->numRects = 0;
781
782 /*
783 * Allocate a reasonable number of rectangles for the new region. The idea
784 * is to allocate enough so the individual functions don't need to
785 * reallocate and copy the array, which is time consuming, yet we don't
786 * have to worry about using too much memory. I hope to be able to
787 * nuke the Xrealloc() at the end of this function eventually.
788 */
789 newReg->size = max(reg1->numRects,reg2->numRects)(((reg1->numRects) > (reg2->numRects)) ? (reg1->numRects
) : (reg2->numRects))
* 2;
790
791 if (! (newReg->rects = (BoxPtr)
792 Xmalloc ((unsigned) (sizeof(BoxRec) * newReg->size))malloc((((unsigned) (sizeof(BoxRec) * newReg->size)) == 0 ?
1 : ((unsigned) (sizeof(BoxRec) * newReg->size))))
)) {
793 newReg->size = 0;
794 return;
795 }
796
797 /*
798 * Initialize ybot and ytop.
799 * In the upcoming loop, ybot and ytop serve different functions depending
800 * on whether the band being handled is an overlapping or non-overlapping
801 * band.
802 * In the case of a non-overlapping band (only one of the regions
803 * has points in the band), ybot is the bottom of the most recent
804 * intersection and thus clips the top of the rectangles in that band.
805 * ytop is the top of the next intersection between the two regions and
806 * serves to clip the bottom of the rectangles in the current band.
807 * For an overlapping band (where the two regions intersect), ytop clips
808 * the top of the rectangles of both regions and ybot clips the bottoms.
809 */
810 if (reg1->extents.y1 < reg2->extents.y1)
811 ybot = reg1->extents.y1;
812 else
813 ybot = reg2->extents.y1;
814
815 /*
816 * prevBand serves to mark the start of the previous band so rectangles
817 * can be coalesced into larger rectangles. qv. miCoalesce, above.
818 * In the beginning, there is no previous band, so prevBand == curBand
819 * (curBand is set later on, of course, but the first band will always
820 * start at index 0). prevBand and curBand must be indices because of
821 * the possible expansion, and resultant moving, of the new region's
822 * array of rectangles.
823 */
824 prevBand = 0;
825
826 do
827 {
828 curBand = newReg->numRects;
829
830 /*
831 * This algorithm proceeds one source-band (as opposed to a
832 * destination band, which is determined by where the two regions
833 * intersect) at a time. r1BandEnd and r2BandEnd serve to mark the
834 * rectangle after the last one in the current band for their
835 * respective regions.
836 */
837 r1BandEnd = r1;
838 while ((r1BandEnd != r1End) && (r1BandEnd->y1 == r1->y1))
839 {
840 r1BandEnd++;
841 }
842
843 r2BandEnd = r2;
844 while ((r2BandEnd != r2End) && (r2BandEnd->y1 == r2->y1))
845 {
846 r2BandEnd++;
847 }
848
849 /*
850 * First handle the band that doesn't intersect, if any.
851 *
852 * Note that attention is restricted to one band in the
853 * non-intersecting region at once, so if a region has n
854 * bands between the current position and the next place it overlaps
855 * the other, this entire loop will be passed through n times.
856 */
857 if (r1->y1 < r2->y1)
858 {
859 top = max(r1->y1,ybot)(((r1->y1) > (ybot)) ? (r1->y1) : (ybot));
860 bot = min(r1->y2,r2->y1)(((r1->y2) < (r2->y1)) ? (r1->y2) : (r2->y1));
861
862 if ((top != bot) && (nonOverlap1Func != NULL((void*)0)))
863 {
864 (* nonOverlap1Func) (newReg, r1, r1BandEnd, top, bot);
865 }
866
867 ytop = r2->y1;
868 }
869 else if (r2->y1 < r1->y1)
870 {
871 top = max(r2->y1,ybot)(((r2->y1) > (ybot)) ? (r2->y1) : (ybot));
872 bot = min(r2->y2,r1->y1)(((r2->y2) < (r1->y1)) ? (r2->y2) : (r1->y1));
873
874 if ((top != bot) && (nonOverlap2Func != NULL((void*)0)))
875 {
876 (* nonOverlap2Func) (newReg, r2, r2BandEnd, top, bot);
877 }
878
879 ytop = r1->y1;
880 }
881 else
882 {
883 ytop = r1->y1;
884 }
885
886 /*
887 * If any rectangles got added to the region, try and coalesce them
888 * with rectangles from the previous band. Note we could just do
889 * this test in miCoalesce, but some machines incur a not
890 * inconsiderable cost for function calls, so...
891 */
892 if (newReg->numRects != curBand)
893 {
894 prevBand = miCoalesce (newReg, prevBand, curBand);
895 }
896
897 /*
898 * Now see if we've hit an intersecting band. The two bands only
899 * intersect if ybot > ytop
900 */
901 ybot = min(r1->y2, r2->y2)(((r1->y2) < (r2->y2)) ? (r1->y2) : (r2->y2));
902 curBand = newReg->numRects;
903 if (ybot > ytop)
904 {
905 (* overlapFunc) (newReg, r1, r1BandEnd, r2, r2BandEnd, ytop, ybot);
906
907 }
908
909 if (newReg->numRects != curBand)
910 {
911 prevBand = miCoalesce (newReg, prevBand, curBand);
912 }
913
914 /*
915 * If we've finished with a band (y2 == ybot) we skip forward
916 * in the region to the next band.
917 */
918 if (r1->y2 == ybot)
919 {
920 r1 = r1BandEnd;
921 }
922 if (r2->y2 == ybot)
923 {
924 r2 = r2BandEnd;
925 }
926 } while ((r1 != r1End) && (r2 != r2End));
927
928 /*
929 * Deal with whichever region still has rectangles left.
930 */
931 curBand = newReg->numRects;
932 if (r1 != r1End)
933 {
934 if (nonOverlap1Func != NULL((void*)0))
935 {
936 do
937 {
938 r1BandEnd = r1;
939 while ((r1BandEnd < r1End) && (r1BandEnd->y1 == r1->y1))
940 {
941 r1BandEnd++;
942 }
943 (* nonOverlap1Func) (newReg, r1, r1BandEnd,
944 max(r1->y1,ybot)(((r1->y1) > (ybot)) ? (r1->y1) : (ybot)), r1->y2);
945 r1 = r1BandEnd;
946 } while (r1 != r1End);
947 }
948 }
949 else if ((r2 != r2End) && (nonOverlap2Func != NULL((void*)0)))
950 {
951 do
952 {
953 r2BandEnd = r2;
954 while ((r2BandEnd < r2End) && (r2BandEnd->y1 == r2->y1))
955 {
956 r2BandEnd++;
957 }
958 (* nonOverlap2Func) (newReg, r2, r2BandEnd,
959 max(r2->y1,ybot)(((r2->y1) > (ybot)) ? (r2->y1) : (ybot)), r2->y2);
960 r2 = r2BandEnd;
961 } while (r2 != r2End);
962 }
963
964 if (newReg->numRects != curBand)
965 {
966 (void) miCoalesce (newReg, prevBand, curBand);
967 }
968
969 /*
970 * A bit of cleanup. To keep regions from growing without bound,
971 * we shrink the array of rectangles to match the new number of
972 * rectangles in the region. This never goes to 0, however...
973 *
974 * Only do this stuff if the number of rectangles allocated is more than
975 * twice the number of rectangles in the region (a simple optimization...).
976 */
977 if (newReg->numRects < (newReg->size >> 1))
978 {
979 if (REGION_NOT_EMPTY(newReg)newReg->numRects)
980 {
981 BoxPtr prev_rects = newReg->rects;
982 newReg->size = newReg->numRects;
983 newReg->rects = (BoxPtr) Xrealloc ((char *) newReg->rects,realloc(((char *) newReg->rects), (((unsigned) (sizeof(BoxRec
) * newReg->size)) == 0 ? 1 : ((unsigned) (sizeof(BoxRec) *
newReg->size))))
984 (unsigned) (sizeof(BoxRec) * newReg->size))realloc(((char *) newReg->rects), (((unsigned) (sizeof(BoxRec
) * newReg->size)) == 0 ? 1 : ((unsigned) (sizeof(BoxRec) *
newReg->size))))
;
985 if (! newReg->rects)
986 newReg->rects = prev_rects;
987 }
988 else
989 {
990 /*
991 * No point in doing the extra work involved in an Xrealloc if
992 * the region is empty
993 */
994 newReg->size = 1;
995 Xfree((char *) newReg->rects)free(((char *) newReg->rects));
996 newReg->rects = (BoxPtr) Xmalloc(sizeof(BoxRec))malloc(((sizeof(BoxRec)) == 0 ? 1 : (sizeof(BoxRec))));
997 }
998 }
999 Xfree ((char *) oldRects)free(((char *) oldRects));
1000 return;
1001}
1002
1003
1004/*======================================================================
1005 * Region Union
1006 *====================================================================*/
1007
1008/*-
1009 *-----------------------------------------------------------------------
1010 * miUnionNonO --
1011 * Handle a non-overlapping band for the union operation. Just
1012 * Adds the rectangles into the region. Doesn't have to check for
1013 * subsumption or anything.
1014 *
1015 * Results:
1016 * None.
1017 *
1018 * Side Effects:
1019 * pReg->numRects is incremented and the final rectangles overwritten
1020 * with the rectangles we're passed.
1021 *
1022 *-----------------------------------------------------------------------
1023 */
1024/* static void*/
1025static int
1026miUnionNonO (
1027 register Region pReg,
1028 register BoxPtr r,
1029 BoxPtr rEnd,
1030 register short y1,
1031 register short y2)
1032{
1033 register BoxPtr pNextRect;
1034
1035 pNextRect = &pReg->rects[pReg->numRects];
1036
1037 assert(y1 < y2);
1038
1039 while (r != rEnd)
1040 {
1041 assert(r->x1 < r->x2);
1042 MEMCHECK(pReg, pNextRect, pReg->rects){ if ((pReg)->numRects >= ((pReg)->size - 1)){ (pReg
->rects) = (BOX *) realloc(((char *)(pReg->rects)), (((
unsigned) (2 * (sizeof(BOX)) * ((pReg)->size))) == 0 ? 1 :
((unsigned) (2 * (sizeof(BOX)) * ((pReg)->size))))); if (
(pReg->rects) == 0) return(0); (pReg)->size *= 2; (pNextRect
) = &(pReg->rects)[(pReg)->numRects]; } }
;
1043 pNextRect->x1 = r->x1;
1044 pNextRect->y1 = y1;
1045 pNextRect->x2 = r->x2;
1046 pNextRect->y2 = y2;
1047 pReg->numRects += 1;
1048 pNextRect++;
1049
1050 assert(pReg->numRects<=pReg->size);
1051 r++;
1052 }
1053 return 0; /* lint */
1054}
1055
1056
1057/*-
1058 *-----------------------------------------------------------------------
1059 * miUnionO --
1060 * Handle an overlapping band for the union operation. Picks the
1061 * left-most rectangle each time and merges it into the region.
1062 *
1063 * Results:
1064 * None.
1065 *
1066 * Side Effects:
1067 * Rectangles are overwritten in pReg->rects and pReg->numRects will
1068 * be changed.
1069 *
1070 *-----------------------------------------------------------------------
1071 */
1072
1073/* static void*/
1074static int
1075miUnionO (
1076 register Region pReg,
1077 register BoxPtr r1,
1078 BoxPtr r1End,
1079 register BoxPtr r2,
1080 BoxPtr r2End,
1081 register short y1,
1082 register short y2)
1083{
1084 register BoxPtr pNextRect;
1085
1086 pNextRect = &pReg->rects[pReg->numRects];
1087
1088#define MERGERECT(r)if ((pReg->numRects != 0) && (pNextRect[-1].y1 == y1
) && (pNextRect[-1].y2 == y2) && (pNextRect[-
1].x2 >= r->x1)) { if (pNextRect[-1].x2 < r->x2) {
pNextRect[-1].x2 = r->x2; ; } } else { { if ((pReg)->numRects
>= ((pReg)->size - 1)){ (pReg->rects) = (BOX *) realloc
(((char *)(pReg->rects)), (((unsigned) (2 * (sizeof(BOX)) *
((pReg)->size))) == 0 ? 1 : ((unsigned) (2 * (sizeof(BOX)
) * ((pReg)->size))))); if ((pReg->rects) == 0) return(
0); (pReg)->size *= 2; (pNextRect) = &(pReg->rects)
[(pReg)->numRects]; } }; pNextRect->y1 = y1; pNextRect->
y2 = y2; pNextRect->x1 = r->x1; pNextRect->x2 = r->
x2; pReg->numRects += 1; pNextRect += 1; } ; r++;
\
1089 if ((pReg->numRects != 0) && \
1090 (pNextRect[-1].y1 == y1) && \
1091 (pNextRect[-1].y2 == y2) && \
1092 (pNextRect[-1].x2 >= r->x1)) \
1093 { \
1094 if (pNextRect[-1].x2 < r->x2) \
1095 { \
1096 pNextRect[-1].x2 = r->x2; \
1097 assert(pNextRect[-1].x1<pNextRect[-1].x2); \
1098 } \
1099 } \
1100 else \
1101 { \
1102 MEMCHECK(pReg, pNextRect, pReg->rects){ if ((pReg)->numRects >= ((pReg)->size - 1)){ (pReg
->rects) = (BOX *) realloc(((char *)(pReg->rects)), (((
unsigned) (2 * (sizeof(BOX)) * ((pReg)->size))) == 0 ? 1 :
((unsigned) (2 * (sizeof(BOX)) * ((pReg)->size))))); if (
(pReg->rects) == 0) return(0); (pReg)->size *= 2; (pNextRect
) = &(pReg->rects)[(pReg)->numRects]; } }
; \
1103 pNextRect->y1 = y1; \
1104 pNextRect->y2 = y2; \
1105 pNextRect->x1 = r->x1; \
1106 pNextRect->x2 = r->x2; \
1107 pReg->numRects += 1; \
1108 pNextRect += 1; \
1109 } \
1110 assert(pReg->numRects<=pReg->size);\
1111 r++;
1112
1113 assert (y1<y2);
1114 while ((r1 != r1End) && (r2 != r2End))
1115 {
1116 if (r1->x1 < r2->x1)
1117 {
1118 MERGERECT(r1)if ((pReg->numRects != 0) && (pNextRect[-1].y1 == y1
) && (pNextRect[-1].y2 == y2) && (pNextRect[-
1].x2 >= r1->x1)) { if (pNextRect[-1].x2 < r1->x2
) { pNextRect[-1].x2 = r1->x2; ; } } else { { if ((pReg)->
numRects >= ((pReg)->size - 1)){ (pReg->rects) = (BOX
*) realloc(((char *)(pReg->rects)), (((unsigned) (2 * (sizeof
(BOX)) * ((pReg)->size))) == 0 ? 1 : ((unsigned) (2 * (sizeof
(BOX)) * ((pReg)->size))))); if ((pReg->rects) == 0) return
(0); (pReg)->size *= 2; (pNextRect) = &(pReg->rects
)[(pReg)->numRects]; } }; pNextRect->y1 = y1; pNextRect
->y2 = y2; pNextRect->x1 = r1->x1; pNextRect->x2 =
r1->x2; pReg->numRects += 1; pNextRect += 1; } ; r1++;
;
1119 }
1120 else
1121 {
1122 MERGERECT(r2)if ((pReg->numRects != 0) && (pNextRect[-1].y1 == y1
) && (pNextRect[-1].y2 == y2) && (pNextRect[-
1].x2 >= r2->x1)) { if (pNextRect[-1].x2 < r2->x2
) { pNextRect[-1].x2 = r2->x2; ; } } else { { if ((pReg)->
numRects >= ((pReg)->size - 1)){ (pReg->rects) = (BOX
*) realloc(((char *)(pReg->rects)), (((unsigned) (2 * (sizeof
(BOX)) * ((pReg)->size))) == 0 ? 1 : ((unsigned) (2 * (sizeof
(BOX)) * ((pReg)->size))))); if ((pReg->rects) == 0) return
(0); (pReg)->size *= 2; (pNextRect) = &(pReg->rects
)[(pReg)->numRects]; } }; pNextRect->y1 = y1; pNextRect
->y2 = y2; pNextRect->x1 = r2->x1; pNextRect->x2 =
r2->x2; pReg->numRects += 1; pNextRect += 1; } ; r2++;
;
1123 }
1124 }
1125
1126 if (r1 != r1End)
1127 {
1128 do
1129 {
1130 MERGERECT(r1)if ((pReg->numRects != 0) && (pNextRect[-1].y1 == y1
) && (pNextRect[-1].y2 == y2) && (pNextRect[-
1].x2 >= r1->x1)) { if (pNextRect[-1].x2 < r1->x2
) { pNextRect[-1].x2 = r1->x2; ; } } else { { if ((pReg)->
numRects >= ((pReg)->size - 1)){ (pReg->rects) = (BOX
*) realloc(((char *)(pReg->rects)), (((unsigned) (2 * (sizeof
(BOX)) * ((pReg)->size))) == 0 ? 1 : ((unsigned) (2 * (sizeof
(BOX)) * ((pReg)->size))))); if ((pReg->rects) == 0) return
(0); (pReg)->size *= 2; (pNextRect) = &(pReg->rects
)[(pReg)->numRects]; } }; pNextRect->y1 = y1; pNextRect
->y2 = y2; pNextRect->x1 = r1->x1; pNextRect->x2 =
r1->x2; pReg->numRects += 1; pNextRect += 1; } ; r1++;
;
1131 } while (r1 != r1End);
1132 }
1133 else while (r2 != r2End)
1134 {
1135 MERGERECT(r2)if ((pReg->numRects != 0) && (pNextRect[-1].y1 == y1
) && (pNextRect[-1].y2 == y2) && (pNextRect[-
1].x2 >= r2->x1)) { if (pNextRect[-1].x2 < r2->x2
) { pNextRect[-1].x2 = r2->x2; ; } } else { { if ((pReg)->
numRects >= ((pReg)->size - 1)){ (pReg->rects) = (BOX
*) realloc(((char *)(pReg->rects)), (((unsigned) (2 * (sizeof
(BOX)) * ((pReg)->size))) == 0 ? 1 : ((unsigned) (2 * (sizeof
(BOX)) * ((pReg)->size))))); if ((pReg->rects) == 0) return
(0); (pReg)->size *= 2; (pNextRect) = &(pReg->rects
)[(pReg)->numRects]; } }; pNextRect->y1 = y1; pNextRect
->y2 = y2; pNextRect->x1 = r2->x1; pNextRect->x2 =
r2->x2; pReg->numRects += 1; pNextRect += 1; } ; r2++;
;
1136 }
1137 return 0; /* lint */
1138}
1139
1140int
1141XUnionRegion(
1142 Region reg1,
1143 Region reg2, /* source regions */
1144 Region newReg) /* destination Region */
1145{
1146 /* checks all the simple cases */
1147
1148 /*
1149 * Region 1 and 2 are the same or region 1 is empty
1150 */
1151 if ( (reg1 == reg2) || (!(reg1->numRects)) )
1152 {
1153 if (newReg != reg2)
1154 miRegionCopy(newReg, reg2);
1155 return 1;
1156 }
1157
1158 /*
1159 * if nothing to union (region 2 empty)
1160 */
1161 if (!(reg2->numRects))
1162 {
1163 if (newReg != reg1)
1164 miRegionCopy(newReg, reg1);
1165 return 1;
1166 }
1167
1168 /*
1169 * Region 1 completely subsumes region 2
1170 */
1171 if ((reg1->numRects == 1) &&
1172 (reg1->extents.x1 <= reg2->extents.x1) &&
1173 (reg1->extents.y1 <= reg2->extents.y1) &&
1174 (reg1->extents.x2 >= reg2->extents.x2) &&
1175 (reg1->extents.y2 >= reg2->extents.y2))
1176 {
1177 if (newReg != reg1)
1178 miRegionCopy(newReg, reg1);
1179 return 1;
1180 }
1181
1182 /*
1183 * Region 2 completely subsumes region 1
1184 */
1185 if ((reg2->numRects == 1) &&
1186 (reg2->extents.x1 <= reg1->extents.x1) &&
1187 (reg2->extents.y1 <= reg1->extents.y1) &&
1188 (reg2->extents.x2 >= reg1->extents.x2) &&
1189 (reg2->extents.y2 >= reg1->extents.y2))
1190 {
1191 if (newReg != reg2)
1192 miRegionCopy(newReg, reg2);
1193 return 1;
1194 }
1195
1196 miRegionOp (newReg, reg1, reg2, miUnionO,
1197 miUnionNonO, miUnionNonO);
1198
1199 newReg->extents.x1 = min(reg1->extents.x1, reg2->extents.x1)(((reg1->extents.x1) < (reg2->extents.x1)) ? (reg1->
extents.x1) : (reg2->extents.x1))
;
1200 newReg->extents.y1 = min(reg1->extents.y1, reg2->extents.y1)(((reg1->extents.y1) < (reg2->extents.y1)) ? (reg1->
extents.y1) : (reg2->extents.y1))
;
1201 newReg->extents.x2 = max(reg1->extents.x2, reg2->extents.x2)(((reg1->extents.x2) > (reg2->extents.x2)) ? (reg1->
extents.x2) : (reg2->extents.x2))
;
1202 newReg->extents.y2 = max(reg1->extents.y2, reg2->extents.y2)(((reg1->extents.y2) > (reg2->extents.y2)) ? (reg1->
extents.y2) : (reg2->extents.y2))
;
1203
1204 return 1;
1205}
1206
1207
1208/*======================================================================
1209 * Region Subtraction
1210 *====================================================================*/
1211
1212/*-
1213 *-----------------------------------------------------------------------
1214 * miSubtractNonO --
1215 * Deal with non-overlapping band for subtraction. Any parts from
1216 * region 2 we discard. Anything from region 1 we add to the region.
1217 *
1218 * Results:
1219 * None.
1220 *
1221 * Side Effects:
1222 * pReg may be affected.
1223 *
1224 *-----------------------------------------------------------------------
1225 */
1226/* static void*/
1227static int
1228miSubtractNonO1 (
1229 register Region pReg,
1230 register BoxPtr r,
1231 BoxPtr rEnd,
1232 register short y1,
1233 register short y2)
1234{
1235 register BoxPtr pNextRect;
1236
1237 pNextRect = &pReg->rects[pReg->numRects];
1238
1239 assert(y1<y2);
1240
1241 while (r != rEnd)
1242 {
1243 assert(r->x1<r->x2);
1244 MEMCHECK(pReg, pNextRect, pReg->rects){ if ((pReg)->numRects >= ((pReg)->size - 1)){ (pReg
->rects) = (BOX *) realloc(((char *)(pReg->rects)), (((
unsigned) (2 * (sizeof(BOX)) * ((pReg)->size))) == 0 ? 1 :
((unsigned) (2 * (sizeof(BOX)) * ((pReg)->size))))); if (
(pReg->rects) == 0) return(0); (pReg)->size *= 2; (pNextRect
) = &(pReg->rects)[(pReg)->numRects]; } }
;
1245 pNextRect->x1 = r->x1;
1246 pNextRect->y1 = y1;
1247 pNextRect->x2 = r->x2;
1248 pNextRect->y2 = y2;
1249 pReg->numRects += 1;
1250 pNextRect++;
1251
1252 assert(pReg->numRects <= pReg->size);
1253
1254 r++;
1255 }
1256 return 0; /* lint */
1257}
1258
1259/*-
1260 *-----------------------------------------------------------------------
1261 * miSubtractO --
1262 * Overlapping band subtraction. x1 is the left-most point not yet
1263 * checked.
1264 *
1265 * Results:
1266 * None.
1267 *
1268 * Side Effects:
1269 * pReg may have rectangles added to it.
1270 *
1271 *-----------------------------------------------------------------------
1272 */
1273/* static void*/
1274static int
1275miSubtractO (
1276 register Region pReg,
1277 register BoxPtr r1,
1278 BoxPtr r1End,
1279 register BoxPtr r2,
1280 BoxPtr r2End,
1281 register short y1,
1282 register short y2)
1283{
1284 register BoxPtr pNextRect;
1285 register int x1;
1286
1287 x1 = r1->x1;
1288
1289 assert(y1<y2);
1290 pNextRect = &pReg->rects[pReg->numRects];
1291
1292 while ((r1 != r1End) && (r2 != r2End))
1293 {
1294 if (r2->x2 <= x1)
1295 {
1296 /*
1297 * Subtrahend missed the boat: go to next subtrahend.
1298 */
1299 r2++;
1300 }
1301 else if (r2->x1 <= x1)
1302 {
1303 /*
1304 * Subtrahend preceeds minuend: nuke left edge of minuend.
1305 */
1306 x1 = r2->x2;
1307 if (x1 >= r1->x2)
1308 {
1309 /*
1310 * Minuend completely covered: advance to next minuend and
1311 * reset left fence to edge of new minuend.
1312 */
1313 r1++;
1314 if (r1 != r1End)
1315 x1 = r1->x1;
1316 }
1317 else
1318 {
1319 /*
1320 * Subtrahend now used up since it doesn't extend beyond
1321 * minuend
1322 */
1323 r2++;
1324 }
1325 }
1326 else if (r2->x1 < r1->x2)
1327 {
1328 /*
1329 * Left part of subtrahend covers part of minuend: add uncovered
1330 * part of minuend to region and skip to next subtrahend.
1331 */
1332 assert(x1<r2->x1);
1333 MEMCHECK(pReg, pNextRect, pReg->rects){ if ((pReg)->numRects >= ((pReg)->size - 1)){ (pReg
->rects) = (BOX *) realloc(((char *)(pReg->rects)), (((
unsigned) (2 * (sizeof(BOX)) * ((pReg)->size))) == 0 ? 1 :
((unsigned) (2 * (sizeof(BOX)) * ((pReg)->size))))); if (
(pReg->rects) == 0) return(0); (pReg)->size *= 2; (pNextRect
) = &(pReg->rects)[(pReg)->numRects]; } }
;
1334 pNextRect->x1 = x1;
1335 pNextRect->y1 = y1;
1336 pNextRect->x2 = r2->x1;
1337 pNextRect->y2 = y2;
1338 pReg->numRects += 1;
1339 pNextRect++;
1340
1341 assert(pReg->numRects<=pReg->size);
1342
1343 x1 = r2->x2;
1344 if (x1 >= r1->x2)
1345 {
1346 /*
1347 * Minuend used up: advance to new...
1348 */
1349 r1++;
1350 if (r1 != r1End)
1351 x1 = r1->x1;
1352 }
1353 else
1354 {
1355 /*
1356 * Subtrahend used up
1357 */
1358 r2++;
1359 }
1360 }
1361 else
1362 {
1363 /*
1364 * Minuend used up: add any remaining piece before advancing.
1365 */
1366 if (r1->x2 > x1)
1367 {
1368 MEMCHECK(pReg, pNextRect, pReg->rects){ if ((pReg)->numRects >= ((pReg)->size - 1)){ (pReg
->rects) = (BOX *) realloc(((char *)(pReg->rects)), (((
unsigned) (2 * (sizeof(BOX)) * ((pReg)->size))) == 0 ? 1 :
((unsigned) (2 * (sizeof(BOX)) * ((pReg)->size))))); if (
(pReg->rects) == 0) return(0); (pReg)->size *= 2; (pNextRect
) = &(pReg->rects)[(pReg)->numRects]; } }
;
1369 pNextRect->x1 = x1;
1370 pNextRect->y1 = y1;
1371 pNextRect->x2 = r1->x2;
1372 pNextRect->y2 = y2;
1373 pReg->numRects += 1;
1374 pNextRect++;
1375 assert(pReg->numRects<=pReg->size);
1376 }
1377 r1++;
1378 if (r1 != r1End)
1379 x1 = r1->x1;
1380 }
1381 }
1382
1383 /*
1384 * Add remaining minuend rectangles to region.
1385 */
1386 while (r1 != r1End)
1387 {
1388 assert(x1<r1->x2);
1389 MEMCHECK(pReg, pNextRect, pReg->rects){ if ((pReg)->numRects >= ((pReg)->size - 1)){ (pReg
->rects) = (BOX *) realloc(((char *)(pReg->rects)), (((
unsigned) (2 * (sizeof(BOX)) * ((pReg)->size))) == 0 ? 1 :
((unsigned) (2 * (sizeof(BOX)) * ((pReg)->size))))); if (
(pReg->rects) == 0) return(0); (pReg)->size *= 2; (pNextRect
) = &(pReg->rects)[(pReg)->numRects]; } }
;
1390 pNextRect->x1 = x1;
1391 pNextRect->y1 = y1;
1392 pNextRect->x2 = r1->x2;
1393 pNextRect->y2 = y2;
1394 pReg->numRects += 1;
1395 pNextRect++;
1396
1397 assert(pReg->numRects<=pReg->size);
1398
1399 r1++;
1400 if (r1 != r1End)
1401 {
1402 x1 = r1->x1;
1403 }
1404 }
1405 return 0; /* lint */
1406}
1407
1408/*-
1409 *-----------------------------------------------------------------------
1410 * miSubtract --
1411 * Subtract regS from regM and leave the result in regD.
1412 * S stands for subtrahend, M for minuend and D for difference.
1413 *
1414 * Results:
1415 * TRUE.
1416 *
1417 * Side Effects:
1418 * regD is overwritten.
1419 *
1420 *-----------------------------------------------------------------------
1421 */
1422
1423int
1424XSubtractRegion(
1425 Region regM,
1426 Region regS,
1427 register Region regD)
1428{
1429 /* check for trivial reject */
1430 if ( (!(regM->numRects)) || (!(regS->numRects)) ||
1431 (!EXTENTCHECK(&regM->extents, &regS->extents)((&regM->extents)->x2 > (&regS->extents)->
x1 && (&regM->extents)->x1 < (&regS->
extents)->x2 && (&regM->extents)->y2 >
(&regS->extents)->y1 && (&regM->extents
)->y1 < (&regS->extents)->y2)
) )
1432 {
1433 miRegionCopy(regD, regM);
1434 return 1;
1435 }
1436
1437 miRegionOp (regD, regM, regS, miSubtractO,
1438 miSubtractNonO1, NULL((void*)0));
1439
1440 /*
1441 * Can't alter newReg's extents before we call miRegionOp because
1442 * it might be one of the source regions and miRegionOp depends
1443 * on the extents of those regions being the unaltered. Besides, this
1444 * way there's no checking against rectangles that will be nuked
1445 * due to coalescing, so we have to examine fewer rectangles.
1446 */
1447 miSetExtents (regD);
1448 return 1;
1449}
1450
1451int
1452XXorRegion(Region sra, Region srb, Region dr)
1453{
1454 Region tra, trb;
1455
1456 if (! (tra = XCreateRegion()) )
1457 return 0;
1458 if (! (trb = XCreateRegion()) ) {
1459 XDestroyRegion(tra);
1460 return 0;
1461 }
1462 (void) XSubtractRegion(sra,srb,tra);
1463 (void) XSubtractRegion(srb,sra,trb);
1464 (void) XUnionRegion(tra,trb,dr);
1465 XDestroyRegion(tra);
1466 XDestroyRegion(trb);
1467 return 0;
1468}
1469
1470/*
1471 * Check to see if the region is empty. Assumes a region is passed
1472 * as a parameter
1473 */
1474int
1475XEmptyRegion(
1476 Region r)
1477{
1478 if( r->numRects == 0 ) return TRUE1;
1479 else return FALSE0;
1480}
1481
1482/*
1483 * Check to see if two regions are equal
1484 */
1485int
1486XEqualRegion(Region r1, Region r2)
1487{
1488 int i;
1489
1490 if( r1->numRects != r2->numRects ) return FALSE0;
1491 else if( r1->numRects == 0 ) return TRUE1;
1492 else if ( r1->extents.x1 != r2->extents.x1 ) return FALSE0;
1493 else if ( r1->extents.x2 != r2->extents.x2 ) return FALSE0;
1494 else if ( r1->extents.y1 != r2->extents.y1 ) return FALSE0;
1495 else if ( r1->extents.y2 != r2->extents.y2 ) return FALSE0;
1496 else for( i=0; i < r1->numRects; i++ ) {
1497 if ( r1->rects[i].x1 != r2->rects[i].x1 ) return FALSE0;
1498 else if ( r1->rects[i].x2 != r2->rects[i].x2 ) return FALSE0;
1499 else if ( r1->rects[i].y1 != r2->rects[i].y1 ) return FALSE0;
1500 else if ( r1->rects[i].y2 != r2->rects[i].y2 ) return FALSE0;
1501 }
1502 return TRUE1;
1503}
1504
1505int
1506XPointInRegion(
1507 Region pRegion,
1508 int x, int y)
1509{
1510 int i;
1511
1512 if (pRegion->numRects == 0)
1513 return FALSE0;
1514 if (!INBOX(pRegion->extents, x, y)( ( ((pRegion->extents).x2 > x)) && ( ((pRegion
->extents).x1 <= x)) && ( ((pRegion->extents
).y2 > y)) && ( ((pRegion->extents).y1 <= y)
) )
)
1515 return FALSE0;
1516 for (i=0; i<pRegion->numRects; i++)
1517 {
1518 if (INBOX (pRegion->rects[i], x, y)( ( ((pRegion->rects[i]).x2 > x)) && ( ((pRegion
->rects[i]).x1 <= x)) && ( ((pRegion->rects[
i]).y2 > y)) && ( ((pRegion->rects[i]).y1 <=
y)) )
)
1519 return TRUE1;
1520 }
1521 return FALSE0;
1522}
1523
1524int
1525XRectInRegion(
1526 register Region region,
1527 int rx, int ry,
1528 unsigned int rwidth, unsigned int rheight)
1529{
1530 register BoxPtr pbox;
1531 register BoxPtr pboxEnd;
1532 Box rect;
1533 register BoxPtr prect = &rect;
1534 int partIn, partOut;
1535
1536 prect->x1 = rx;
1537 prect->y1 = ry;
1538 prect->x2 = rwidth + rx;
1539 prect->y2 = rheight + ry;
1540
1541 /* this is (just) a useful optimization */
1542 if ((region->numRects == 0) || !EXTENTCHECK(&region->extents, prect)((&region->extents)->x2 > (prect)->x1 &&
(&region->extents)->x1 < (prect)->x2 &&
(&region->extents)->y2 > (prect)->y1 &&
(&region->extents)->y1 < (prect)->y2)
)
1543 return(RectangleOut0);
1544
1545 partOut = FALSE0;
1546 partIn = FALSE0;
1547
1548 /* can stop when both partOut and partIn are TRUE, or we reach prect->y2 */
1549 for (pbox = region->rects, pboxEnd = pbox + region->numRects;
1550 pbox < pboxEnd;
1551 pbox++)
1552 {
1553
1554 if (pbox->y2 <= ry)
1555 continue; /* getting up to speed or skipping remainder of band */
1556
1557 if (pbox->y1 > ry)
1558 {
1559 partOut = TRUE1; /* missed part of rectangle above */
1560 if (partIn || (pbox->y1 >= prect->y2))
1561 break;
1562 ry = pbox->y1; /* x guaranteed to be == prect->x1 */
1563 }
1564
1565 if (pbox->x2 <= rx)
1566 continue; /* not far enough over yet */
1567
1568 if (pbox->x1 > rx)
1569 {
1570 partOut = TRUE1; /* missed part of rectangle to left */
1571 if (partIn)
1572 break;
1573 }
1574
1575 if (pbox->x1 < prect->x2)
1576 {
1577 partIn = TRUE1; /* definitely overlap */
1578 if (partOut)
1579 break;
1580 }
1581
1582 if (pbox->x2 >= prect->x2)
1583 {
1584 ry = pbox->y2; /* finished with this band */
1585 if (ry >= prect->y2)
1586 break;
1587 rx = prect->x1; /* reset x out to left again */
1588 } else
1589 {
1590 /*
1591 * Because boxes in a band are maximal width, if the first box
1592 * to overlap the rectangle doesn't completely cover it in that
1593 * band, the rectangle must be partially out, since some of it
1594 * will be uncovered in that band. partIn will have been set true
1595 * by now...
1596 */
1597 break;
1598 }
1599
1600 }
1601
1602 return(partIn ? ((ry < prect->y2) ? RectanglePart2 : RectangleIn1) :
1603 RectangleOut0);
1604}