1 /* $OpenBSD: diff3.c,v 1.45 2021/04/13 14:20:24 stsp Exp $ */
2
3 /*
4 * Copyright (C) Caldera International Inc. 2001-2002.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code and documentation must retain the above
11 * copyright notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 * must display the following acknowledgement:
17 * This product includes software developed or owned by Caldera
18 * International, Inc.
19 * 4. Neither the name of Caldera International, Inc. nor the names of other
20 * contributors may be used to endorse or promote products derived from
21 * this software without specific prior written permission.
22 *
23 * USE OF THE SOFTWARE PROVIDED FOR UNDER THIS LICENSE BY CALDERA
24 * INTERNATIONAL, INC. AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR
25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27 * IN NO EVENT SHALL CALDERA INTERNATIONAL, INC. BE LIABLE FOR ANY DIRECT,
28 * INDIRECT INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
29 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
30 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
32 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
33 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
34 * POSSIBILITY OF SUCH DAMAGE.
35 */
36 /*-
37 * Copyright (c) 1991, 1993
38 * The Regents of the University of California. All rights reserved.
39 *
40 * Redistribution and use in source and binary forms, with or without
41 * modification, are permitted provided that the following conditions
42 * are met:
43 * 1. Redistributions of source code must retain the above copyright
44 * notice, this list of conditions and the following disclaimer.
45 * 2. Redistributions in binary form must reproduce the above copyright
46 * notice, this list of conditions and the following disclaimer in the
47 * documentation and/or other materials provided with the distribution.
48 * 3. Neither the name of the University nor the names of its contributors
49 * may be used to endorse or promote products derived from this software
50 * without specific prior written permission.
51 *
52 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
53 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
54 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
55 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
56 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
57 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
58 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
59 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
60 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
61 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
62 * SUCH DAMAGE.
63 *
64 * @(#)diff3.c 8.1 (Berkeley) 6/6/93
65 */
66
67 #include <ctype.h>
68 #include <err.h>
69 #include <stdio.h>
70 #include <stdlib.h>
71 #include <string.h>
72 #include <time.h>
73 #include <unistd.h>
74
75 #include "diff.h"
76 #include "rcsprog.h"
77
78 /* diff3 - 3-way differential file comparison */
79
80 /* diff3 [-ex3EX] d13 d23 f1 f2 f3 [m1 m3]
81 *
82 * d13 = diff report on f1 vs f3
83 * d23 = diff report on f2 vs f3
84 * f1, f2, f3 the 3 files
85 * if changes in f1 overlap with changes in f3, m1 and m3 are used
86 * to mark the overlaps; otherwise, the file names f1 and f3 are used
87 * (only for options E and X).
88 */
89
90 /*
91 * "from" is first in range of changed lines; "to" is last+1
92 * from=to=line after point of insertion for added lines.
93 */
94 struct range {
95 int from;
96 int to;
97 };
98
99 struct diff {
100 struct range old;
101 struct range new;
102 };
103
104 static size_t szchanges;
105
106 static struct diff *d13;
107 static struct diff *d23;
108
109 /*
110 * "de" is used to gather editing scripts. These are later spewed out in
111 * reverse order. Its first element must be all zero, the "new" component
112 * of "de" contains line positions or byte positions depending on when you
113 * look (!?). Array overlap indicates which sections in "de" correspond to
114 * lines that are different in all three files.
115 */
116 static struct diff *de;
117 static char *overlap;
118 static int overlapcnt = 0;
119 static FILE *fp[3];
120 static int cline[3]; /* # of the last-read line in each file (0-2) */
121
122 /*
123 * the latest known correspondence between line numbers of the 3 files
124 * is stored in last[1-3];
125 */
126 static int last[4];
127 static int eflag = 3; /* default -E for compatibility with former RCS */
128 static int oflag = 1; /* default -E for compatibility with former RCS */
129 static int debug = 0;
130 static char f1mark[PATH_MAX], f3mark[PATH_MAX]; /* markers for -E and -X */
131
132 static int duplicate(struct range *, struct range *);
133 static int edit(struct diff *, int, int);
134 static char *getchange(FILE *);
135 static char *get_line(FILE *, size_t *);
136 static int number(char **);
137 static ssize_t readin(char *, struct diff **);
138 static int skip(int, int, char *);
139 static int edscript(int);
140 static int merge(size_t, size_t);
141 static void change(int, struct range *, int);
142 static void keep(int, struct range *);
143 static void prange(struct range *);
144 static void repos(int);
145 static void separate(const char *);
146 static void increase(void);
147 static int diff3_internal(int, char **, const char *, const char *);
148
149 int diff3_conflicts = 0;
150
151 /*
152 * For merge(1).
153 */
154 BUF *
merge_diff3(char ** av,int flags)155 merge_diff3(char **av, int flags)
156 {
157 int argc;
158 char *argv[5], *dp13, *dp23, *path1, *path2, *path3;
159 BUF *b1, *b2, *b3, *d1, *d2, *diffb;
160 u_char *data, *patch;
161 size_t dlen, plen;
162
163 b1 = b2 = b3 = d1 = d2 = diffb = NULL;
164 dp13 = dp23 = path1 = path2 = path3 = NULL;
165 data = patch = NULL;
166
167 if ((flags & MERGE_EFLAG) && !(flags & MERGE_OFLAG))
168 oflag = 0;
169
170 if ((b1 = buf_load(av[0])) == NULL)
171 goto out;
172 if ((b2 = buf_load(av[1])) == NULL)
173 goto out;
174 if ((b3 = buf_load(av[2])) == NULL)
175 goto out;
176
177 d1 = buf_alloc(128);
178 d2 = buf_alloc(128);
179 diffb = buf_alloc(128);
180
181 (void)xasprintf(&path1, "%s/diff1.XXXXXXXXXX", rcs_tmpdir);
182 (void)xasprintf(&path2, "%s/diff2.XXXXXXXXXX", rcs_tmpdir);
183 (void)xasprintf(&path3, "%s/diff3.XXXXXXXXXX", rcs_tmpdir);
184
185 buf_write_stmp(b1, path1);
186 buf_write_stmp(b2, path2);
187 buf_write_stmp(b3, path3);
188
189 buf_free(b2);
190 b2 = NULL;
191
192 if ((diffreg(path1, path3, d1, D_FORCEASCII) == D_ERROR) ||
193 (diffreg(path2, path3, d2, D_FORCEASCII) == D_ERROR)) {
194 buf_free(diffb);
195 diffb = NULL;
196 goto out;
197 }
198
199 (void)xasprintf(&dp13, "%s/d13.XXXXXXXXXX", rcs_tmpdir);
200 buf_write_stmp(d1, dp13);
201
202 buf_free(d1);
203 d1 = NULL;
204
205 (void)xasprintf(&dp23, "%s/d23.XXXXXXXXXX", rcs_tmpdir);
206 buf_write_stmp(d2, dp23);
207
208 buf_free(d2);
209 d2 = NULL;
210
211 argc = 0;
212 diffbuf = diffb;
213 argv[argc++] = dp13;
214 argv[argc++] = dp23;
215 argv[argc++] = path1;
216 argv[argc++] = path2;
217 argv[argc++] = path3;
218
219 diff3_conflicts = diff3_internal(argc, argv, av[0], av[2]);
220 if (diff3_conflicts < 0) {
221 buf_free(diffb);
222 diffb = NULL;
223 goto out;
224 }
225
226 plen = buf_len(diffb);
227 patch = buf_release(diffb);
228 dlen = buf_len(b1);
229 data = buf_release(b1);
230
231 if ((diffb = rcs_patchfile(data, dlen, patch, plen, ed_patch_lines)) == NULL)
232 goto out;
233
234 if (!(flags & QUIET) && diff3_conflicts != 0)
235 warnx("warning: overlaps or other problems during merge");
236
237 out:
238 buf_free(b2);
239 buf_free(b3);
240 buf_free(d1);
241 buf_free(d2);
242
243 (void)unlink(path1);
244 (void)unlink(path2);
245 (void)unlink(path3);
246 (void)unlink(dp13);
247 (void)unlink(dp23);
248
249 free(path1);
250 free(path2);
251 free(path3);
252 free(dp13);
253 free(dp23);
254 free(data);
255 free(patch);
256
257 return (diffb);
258 }
259
260 BUF *
rcs_diff3(RCSFILE * rf,char * workfile,RCSNUM * rev1,RCSNUM * rev2,int flags)261 rcs_diff3(RCSFILE *rf, char *workfile, RCSNUM *rev1, RCSNUM *rev2, int flags)
262 {
263 int argc;
264 char *argv[5], r1[RCS_REV_BUFSZ], r2[RCS_REV_BUFSZ];
265 char *dp13, *dp23, *path1, *path2, *path3;
266 BUF *b1, *b2, *b3, *d1, *d2, *diffb;
267 size_t dlen, plen;
268 u_char *data, *patch;
269
270 b1 = b2 = b3 = d1 = d2 = diffb = NULL;
271 dp13 = dp23 = path1 = path2 = path3 = NULL;
272 data = patch = NULL;
273
274 if ((flags & MERGE_EFLAG) && !(flags & MERGE_OFLAG))
275 oflag = 0;
276
277 rcsnum_tostr(rev1, r1, sizeof(r1));
278 rcsnum_tostr(rev2, r2, sizeof(r2));
279
280 if ((b1 = buf_load(workfile)) == NULL)
281 goto out;
282
283 if (!(flags & QUIET))
284 (void)fprintf(stderr, "retrieving revision %s\n", r1);
285 if ((b2 = rcs_getrev(rf, rev1)) == NULL)
286 goto out;
287
288 if (!(flags & QUIET))
289 (void)fprintf(stderr, "retrieving revision %s\n", r2);
290 if ((b3 = rcs_getrev(rf, rev2)) == NULL)
291 goto out;
292
293 d1 = buf_alloc(128);
294 d2 = buf_alloc(128);
295 diffb = buf_alloc(128);
296
297 (void)xasprintf(&path1, "%s/diff1.XXXXXXXXXX", rcs_tmpdir);
298 (void)xasprintf(&path2, "%s/diff2.XXXXXXXXXX", rcs_tmpdir);
299 (void)xasprintf(&path3, "%s/diff3.XXXXXXXXXX", rcs_tmpdir);
300
301 buf_write_stmp(b1, path1);
302 buf_write_stmp(b2, path2);
303 buf_write_stmp(b3, path3);
304
305 buf_free(b2);
306 b2 = NULL;
307
308 if ((diffreg(path1, path3, d1, D_FORCEASCII) == D_ERROR) ||
309 (diffreg(path2, path3, d2, D_FORCEASCII) == D_ERROR)) {
310 buf_free(diffb);
311 diffb = NULL;
312 goto out;
313 }
314
315 (void)xasprintf(&dp13, "%s/d13.XXXXXXXXXX", rcs_tmpdir);
316 buf_write_stmp(d1, dp13);
317
318 buf_free(d1);
319 d1 = NULL;
320
321 (void)xasprintf(&dp23, "%s/d23.XXXXXXXXXX", rcs_tmpdir);
322 buf_write_stmp(d2, dp23);
323
324 buf_free(d2);
325 d2 = NULL;
326
327 argc = 0;
328 diffbuf = diffb;
329 argv[argc++] = dp13;
330 argv[argc++] = dp23;
331 argv[argc++] = path1;
332 argv[argc++] = path2;
333 argv[argc++] = path3;
334
335 diff3_conflicts = diff3_internal(argc, argv, workfile, r2);
336 if (diff3_conflicts < 0) {
337 buf_free(diffb);
338 diffb = NULL;
339 goto out;
340 }
341
342 plen = buf_len(diffb);
343 patch = buf_release(diffb);
344 dlen = buf_len(b1);
345 data = buf_release(b1);
346
347 if ((diffb = rcs_patchfile(data, dlen, patch, plen, ed_patch_lines)) == NULL)
348 goto out;
349
350 if (!(flags & QUIET) && diff3_conflicts != 0)
351 warnx("warning: overlaps or other problems during merge");
352
353 out:
354 buf_free(b2);
355 buf_free(b3);
356 buf_free(d1);
357 buf_free(d2);
358
359 (void)unlink(path1);
360 (void)unlink(path2);
361 (void)unlink(path3);
362 (void)unlink(dp13);
363 (void)unlink(dp23);
364
365 free(path1);
366 free(path2);
367 free(path3);
368 free(dp13);
369 free(dp23);
370 free(data);
371 free(patch);
372
373 return (diffb);
374 }
375
376 static int
diff3_internal(int argc,char ** argv,const char * fmark,const char * rmark)377 diff3_internal(int argc, char **argv, const char *fmark, const char *rmark)
378 {
379 ssize_t m, n;
380 int i;
381
382 if (argc < 5)
383 return (-1);
384
385 if (oflag) {
386 i = snprintf(f1mark, sizeof(f1mark), "<<<<<<< %s", fmark);
387 if (i < 0 || i >= (int)sizeof(f1mark))
388 errx(1, "diff3_internal: string truncated");
389
390 i = snprintf(f3mark, sizeof(f3mark), ">>>>>>> %s", rmark);
391 if (i < 0 || i >= (int)sizeof(f3mark))
392 errx(1, "diff3_internal: string truncated");
393 }
394
395 increase();
396 if ((m = readin(argv[0], &d13)) < 0) {
397 warn("%s", argv[0]);
398 return (-1);
399 }
400 if ((n = readin(argv[1], &d23)) < 0) {
401 warn("%s", argv[1]);
402 return (-1);
403 }
404
405 for (i = 0; i <= 2; i++)
406 if ((fp[i] = fopen(argv[i + 2], "r")) == NULL) {
407 warn("%s", argv[i + 2]);
408 return (-1);
409 }
410
411 return (merge(m, n));
412 }
413
414 int
ed_patch_lines(struct rcs_lines * dlines,struct rcs_lines * plines)415 ed_patch_lines(struct rcs_lines *dlines, struct rcs_lines *plines)
416 {
417 char op, *ep;
418 struct rcs_line *sort, *lp, *dlp, *ndlp, *insert_after;
419 int start, end, i, lineno;
420 u_char tmp;
421
422 dlp = TAILQ_FIRST(&(dlines->l_lines));
423 lp = TAILQ_FIRST(&(plines->l_lines));
424
425 end = 0;
426 for (lp = TAILQ_NEXT(lp, l_list); lp != NULL;
427 lp = TAILQ_NEXT(lp, l_list)) {
428 /* Skip blank lines */
429 if (lp->l_len < 2)
430 continue;
431
432 /* NUL-terminate line buffer for strtol() safety. */
433 tmp = lp->l_line[lp->l_len - 1];
434 lp->l_line[lp->l_len - 1] = '\0';
435
436 /* len - 1 is NUL terminator so we use len - 2 for 'op' */
437 op = lp->l_line[lp->l_len - 2];
438 start = (int)strtol(lp->l_line, &ep, 10);
439
440 /* Restore the last byte of the buffer */
441 lp->l_line[lp->l_len - 1] = tmp;
442
443 if (op == 'a') {
444 if (start > dlines->l_nblines ||
445 start < 0 || *ep != 'a')
446 errx(1, "ed_patch_lines");
447 } else if (op == 'c') {
448 if (start > dlines->l_nblines ||
449 start < 0 || (*ep != ',' && *ep != 'c'))
450 errx(1, "ed_patch_lines");
451
452 if (*ep == ',') {
453 ep++;
454 end = (int)strtol(ep, &ep, 10);
455 if (end < 0 || *ep != 'c')
456 errx(1, "ed_patch_lines");
457 } else {
458 end = start;
459 }
460 }
461
462
463 for (;;) {
464 if (dlp == NULL)
465 break;
466 if (dlp->l_lineno == start)
467 break;
468 if (dlp->l_lineno > start) {
469 dlp = TAILQ_PREV(dlp, tqh, l_list);
470 } else if (dlp->l_lineno < start) {
471 ndlp = TAILQ_NEXT(dlp, l_list);
472 if (ndlp->l_lineno > start)
473 break;
474 dlp = ndlp;
475 }
476 }
477
478 if (dlp == NULL)
479 errx(1, "ed_patch_lines");
480
481
482 if (op == 'c') {
483 insert_after = TAILQ_PREV(dlp, tqh, l_list);
484 for (i = 0; i <= (end - start); i++) {
485 ndlp = TAILQ_NEXT(dlp, l_list);
486 TAILQ_REMOVE(&(dlines->l_lines), dlp, l_list);
487 dlp = ndlp;
488 }
489 dlp = insert_after;
490 }
491
492 if (op == 'a' || op == 'c') {
493 for (;;) {
494 ndlp = lp;
495 lp = TAILQ_NEXT(lp, l_list);
496 if (lp == NULL)
497 errx(1, "ed_patch_lines");
498
499 if (lp->l_len == 2 &&
500 lp->l_line[0] == '.' &&
501 lp->l_line[1] == '\n')
502 break;
503
504 TAILQ_REMOVE(&(plines->l_lines), lp, l_list);
505 TAILQ_INSERT_AFTER(&(dlines->l_lines), dlp,
506 lp, l_list);
507 dlp = lp;
508
509 lp->l_lineno = start;
510 lp = ndlp;
511 }
512 }
513
514 /*
515 * always resort lines as the markers might be put at the
516 * same line as we first started editing.
517 */
518 lineno = 0;
519 TAILQ_FOREACH(sort, &(dlines->l_lines), l_list)
520 sort->l_lineno = lineno++;
521 dlines->l_nblines = lineno - 1;
522 }
523
524 return (0);
525 }
526
527 /*
528 * Pick up the line numbers of all changes from one change file.
529 * (This puts the numbers in a vector, which is not strictly necessary,
530 * since the vector is processed in one sequential pass.
531 * The vector could be optimized out of existence)
532 */
533 static ssize_t
readin(char * name,struct diff ** dd)534 readin(char *name, struct diff **dd)
535 {
536 int a, b, c, d;
537 char kind, *p;
538 size_t i;
539
540 fp[0] = fopen(name, "r");
541 if (fp[0] == NULL)
542 return (-1);
543 for (i = 0; (p = getchange(fp[0])); i++) {
544 if (i >= szchanges - 1)
545 increase();
546 a = b = number(&p);
547 if (*p == ',') {
548 p++;
549 b = number(&p);
550 }
551 kind = *p++;
552 c = d = number(&p);
553 if (*p==',') {
554 p++;
555 d = number(&p);
556 }
557 if (kind == 'a')
558 a++;
559 if (kind == 'd')
560 c++;
561 b++;
562 d++;
563 (*dd)[i].old.from = a;
564 (*dd)[i].old.to = b;
565 (*dd)[i].new.from = c;
566 (*dd)[i].new.to = d;
567 }
568
569 if (i) {
570 (*dd)[i].old.from = (*dd)[i-1].old.to;
571 (*dd)[i].new.from = (*dd)[i-1].new.to;
572 }
573
574 (void)fclose(fp[0]);
575
576 return (i);
577 }
578
579 static int
number(char ** lc)580 number(char **lc)
581 {
582 int nn;
583
584 nn = 0;
585 while (isdigit((unsigned char)(**lc)))
586 nn = nn*10 + *(*lc)++ - '0';
587
588 return (nn);
589 }
590
591 static char *
getchange(FILE * b)592 getchange(FILE *b)
593 {
594 char *line;
595
596 while ((line = get_line(b, NULL))) {
597 if (isdigit((unsigned char)line[0]))
598 return (line);
599 }
600
601 return (NULL);
602 }
603
604 static char *
get_line(FILE * b,size_t * n)605 get_line(FILE *b, size_t *n)
606 {
607 char *cp;
608 size_t len;
609 static char *buf;
610 static size_t bufsize;
611
612 if ((cp = fgetln(b, &len)) == NULL)
613 return (NULL);
614
615 if (cp[len - 1] != '\n')
616 len++;
617 if (len + 1 > bufsize) {
618 do {
619 bufsize += 1024;
620 } while (len + 1 > bufsize);
621 buf = xreallocarray(buf, 1, bufsize);
622 }
623 memcpy(buf, cp, len - 1);
624 buf[len - 1] = '\n';
625 buf[len] = '\0';
626 if (n != NULL)
627 *n = len;
628
629 return (buf);
630 }
631
632 static int
merge(size_t m1,size_t m2)633 merge(size_t m1, size_t m2)
634 {
635 struct diff *d1, *d2, *d3;
636 int dpl, j, t1, t2;
637
638 d1 = d13;
639 d2 = d23;
640 j = 0;
641 for (;;) {
642 t1 = (d1 < d13 + m1);
643 t2 = (d2 < d23 + m2);
644 if (!t1 && !t2)
645 break;
646
647 if (debug) {
648 printf("%d,%d=%d,%d %d,%d=%d,%d\n",
649 d1->old.from, d1->old.to,
650 d1->new.from, d1->new.to,
651 d2->old.from, d2->old.to,
652 d2->new.from, d2->new.to);
653 }
654
655 /* first file is different from others */
656 if (!t2 || (t1 && d1->new.to < d2->new.from)) {
657 /* stuff peculiar to 1st file */
658 if (eflag==0) {
659 separate("1");
660 change(1, &d1->old, 0);
661 keep(2, &d1->new);
662 change(3, &d1->new, 0);
663 }
664 d1++;
665 continue;
666 }
667
668 /* second file is different from others */
669 if (!t1 || (t2 && d2->new.to < d1->new.from)) {
670 if (eflag==0) {
671 separate("2");
672 keep(1, &d2->new);
673 change(2, &d2->old, 0);
674 change(3, &d2->new, 0);
675 }
676 d2++;
677 continue;
678 }
679
680 /*
681 * Merge overlapping changes in first file
682 * this happens after extension (see below).
683 */
684 if (d1 + 1 < d13 + m1 && d1->new.to >= d1[1].new.from) {
685 d1[1].old.from = d1->old.from;
686 d1[1].new.from = d1->new.from;
687 d1++;
688 continue;
689 }
690
691 /* merge overlapping changes in second */
692 if (d2 + 1 < d23 + m2 && d2->new.to >= d2[1].new.from) {
693 d2[1].old.from = d2->old.from;
694 d2[1].new.from = d2->new.from;
695 d2++;
696 continue;
697 }
698 /* stuff peculiar to third file or different in all */
699 if (d1->new.from == d2->new.from && d1->new.to == d2->new.to) {
700 dpl = duplicate(&d1->old,&d2->old);
701 if (dpl == -1)
702 return (-1);
703
704 /*
705 * dpl = 0 means all files differ
706 * dpl = 1 means files 1 and 2 identical
707 */
708 if (eflag==0) {
709 separate(dpl ? "3" : "");
710 change(1, &d1->old, dpl);
711 change(2, &d2->old, 0);
712 d3 = d1->old.to > d1->old.from ? d1 : d2;
713 change(3, &d3->new, 0);
714 } else
715 j = edit(d1, dpl, j);
716 d1++;
717 d2++;
718 continue;
719 }
720
721 /*
722 * Overlapping changes from file 1 and 2; extend changes
723 * appropriately to make them coincide.
724 */
725 if (d1->new.from < d2->new.from) {
726 d2->old.from -= d2->new.from-d1->new.from;
727 d2->new.from = d1->new.from;
728 } else if (d2->new.from < d1->new.from) {
729 d1->old.from -= d1->new.from-d2->new.from;
730 d1->new.from = d2->new.from;
731 }
732 if (d1->new.to > d2->new.to) {
733 d2->old.to += d1->new.to - d2->new.to;
734 d2->new.to = d1->new.to;
735 } else if (d2->new.to > d1->new.to) {
736 d1->old.to += d2->new.to - d1->new.to;
737 d1->new.to = d2->new.to;
738 }
739 }
740
741 return (edscript(j));
742 }
743
744 static void
separate(const char * s)745 separate(const char *s)
746 {
747 diff_output("====%s\n", s);
748 }
749
750 /*
751 * The range of lines rold.from thru rold.to in file i is to be changed.
752 * It is to be printed only if it does not duplicate something to be
753 * printed later.
754 */
755 static void
change(int i,struct range * rold,int fdup)756 change(int i, struct range *rold, int fdup)
757 {
758 diff_output("%d:", i);
759 last[i] = rold->to;
760 prange(rold);
761 if (fdup || debug)
762 return;
763 i--;
764 (void)skip(i, rold->from, NULL);
765 (void)skip(i, rold->to, " ");
766 }
767
768 /*
769 * print the range of line numbers, rold.from thru rold.to, as n1,n2 or n1
770 */
771 static void
prange(struct range * rold)772 prange(struct range *rold)
773 {
774 if (rold->to <= rold->from)
775 diff_output("%da\n", rold->from - 1);
776 else {
777 diff_output("%d", rold->from);
778 if (rold->to > rold->from+1)
779 diff_output(",%d", rold->to - 1);
780 diff_output("c\n");
781 }
782 }
783
784 /*
785 * No difference was reported by diff between file 1 (or 2) and file 3,
786 * and an artificial dummy difference (trange) must be ginned up to
787 * correspond to the change reported in the other file.
788 */
789 static void
keep(int i,struct range * rnew)790 keep(int i, struct range *rnew)
791 {
792 int delta;
793 struct range trange;
794
795 delta = last[3] - last[i];
796 trange.from = rnew->from - delta;
797 trange.to = rnew->to - delta;
798 change(i, &trange, 1);
799 }
800
801 /*
802 * skip to just before line number from in file "i". If "pr" is non-NULL,
803 * print all skipped stuff with string pr as a prefix.
804 */
805 static int
skip(int i,int from,char * pr)806 skip(int i, int from, char *pr)
807 {
808 size_t j, n;
809 char *line;
810
811 for (n = 0; cline[i] < from - 1; n += j) {
812 if ((line = get_line(fp[i], &j)) == NULL)
813 return (-1);
814 if (pr != NULL)
815 diff_output("%s%s", pr, line);
816 cline[i]++;
817 }
818 return ((int) n);
819 }
820
821 /*
822 * Return 1 or 0 according as the old range (in file 1) contains exactly
823 * the same data as the new range (in file 2).
824 */
825 static int
duplicate(struct range * r1,struct range * r2)826 duplicate(struct range *r1, struct range *r2)
827 {
828 int c,d;
829 int nchar;
830 int nline;
831
832 if (r1->to-r1->from != r2->to-r2->from)
833 return (0);
834 (void)skip(0, r1->from, NULL);
835 (void)skip(1, r2->from, NULL);
836 nchar = 0;
837 for (nline=0; nline < r1->to - r1->from; nline++) {
838 do {
839 c = getc(fp[0]);
840 d = getc(fp[1]);
841 if (c == -1 && d == -1)
842 break;
843 if (c == -1 || d== -1)
844 return (-1);
845 nchar++;
846 if (c != d) {
847 repos(nchar);
848 return (0);
849 }
850 } while (c != '\n');
851 }
852 repos(nchar);
853 return (1);
854 }
855
856 static void
repos(int nchar)857 repos(int nchar)
858 {
859 int i;
860
861 for (i = 0; i < 2; i++)
862 (void)fseek(fp[i], (long)-nchar, SEEK_CUR);
863 }
864
865 /*
866 * collect an editing script for later regurgitation
867 */
868 static int
edit(struct diff * diff,int fdup,int j)869 edit(struct diff *diff, int fdup, int j)
870 {
871 if (((fdup + 1) & eflag) == 0)
872 return (j);
873 j++;
874 overlap[j] = !fdup;
875 if (!fdup)
876 overlapcnt++;
877 de[j].old.from = diff->old.from;
878 de[j].old.to = diff->old.to;
879 de[j].new.from = de[j-1].new.to + skip(2, diff->new.from, NULL);
880 de[j].new.to = de[j].new.from + skip(2, diff->new.to, NULL);
881 return (j);
882 }
883
884 /* regurgitate */
885 static int
edscript(int n)886 edscript(int n)
887 {
888 int j, k;
889 char block[BUFSIZ+1];
890
891 for (; n > 0; n--) {
892 if (!oflag || !overlap[n])
893 prange(&de[n].old);
894 else
895 diff_output("%da\n=======\n", de[n].old.to -1);
896 (void)fseek(fp[2], (long)de[n].new.from, SEEK_SET);
897 for (k = de[n].new.to-de[n].new.from; k > 0; k-= j) {
898 size_t r;
899 j = k > BUFSIZ ? BUFSIZ : k;
900 r = fread(block, 1, j, fp[2]);
901 if (r == 0) {
902 if (feof(fp[2]))
903 break;
904 return -1;
905 }
906 if (r != (size_t)j)
907 j = r;
908 block[j] = '\0';
909 diff_output("%s", block);
910 }
911
912 if (!oflag || !overlap[n])
913 diff_output(".\n");
914 else {
915 diff_output("%s\n.\n", f3mark);
916 diff_output("%da\n%s\n.\n", de[n].old.from - 1, f1mark);
917 }
918 }
919
920 return (overlapcnt);
921 }
922
923 static void
increase(void)924 increase(void)
925 {
926 size_t newsz, incr;
927
928 /* are the memset(3) calls needed? */
929 newsz = szchanges == 0 ? 64 : 2 * szchanges;
930 incr = newsz - szchanges;
931
932 d13 = xreallocarray(d13, newsz, sizeof(*d13));
933 memset(d13 + szchanges, 0, incr * sizeof(*d13));
934 d23 = xreallocarray(d23, newsz, sizeof(*d23));
935 memset(d23 + szchanges, 0, incr * sizeof(*d23));
936 de = xreallocarray(de, newsz, sizeof(*de));
937 memset(de + szchanges, 0, incr * sizeof(*de));
938 overlap = xreallocarray(overlap, newsz, sizeof(*overlap));
939 memset(overlap + szchanges, 0, incr * sizeof(*overlap));
940 szchanges = newsz;
941 }
942