1 /* $OpenBSD: diff3.c,v 1.65 2021/04/13 14:20:23 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 <errno.h>
69 #include <fcntl.h>
70 #include <stdio.h>
71 #include <stdlib.h>
72 #include <string.h>
73 #include <unistd.h>
74
75 #include "atomicio.h"
76 #include "cvs.h"
77 #include "diff.h"
78
79 /* diff3 - 3-way differential file comparison */
80
81 /* diff3 [-ex3EX] d13 d23 f1 f2 f3 [m1 m3]
82 *
83 * d13 = diff report on f1 vs f3
84 * d23 = diff report on f2 vs f3
85 * f1, f2, f3 the 3 files
86 * if changes in f1 overlap with changes in f3, m1 and m3 are used
87 * to mark the overlaps; otherwise, the file names f1 and f3 are used
88 * (only for options E and X).
89 */
90
91 /*
92 * "from" is first in range of changed lines; "to" is last+1
93 * from=to=line after point of insertion for added lines.
94 */
95 struct range {
96 int from;
97 int to;
98 };
99
100 struct diff {
101 struct range old;
102 struct range new;
103 };
104
105 static size_t szchanges;
106
107 static struct diff *d13;
108 static struct diff *d23;
109
110 /*
111 * "de" is used to gather editing scripts. These are later spewed out in
112 * reverse order. Its first element must be all zero, the "new" component
113 * of "de" contains line positions or byte positions depending on when you
114 * look (!?). Array overlap indicates which sections in "de" correspond to
115 * lines that are different in all three files.
116 */
117 static struct diff *de;
118 static char *overlap;
119 static int overlapcnt = 0;
120 static FILE *fp[3];
121 static int cline[3]; /* # of the last-read line in each file (0-2) */
122
123 /*
124 * the latest known correspondence between line numbers of the 3 files
125 * is stored in last[1-3];
126 */
127 static int last[4];
128 static int eflag;
129 static int oflag; /* indicates whether to mark overlaps (-E or -X)*/
130 static int debug = 0;
131 static char f1mark[PATH_MAX], f3mark[PATH_MAX]; /* markers for -E and -X */
132
133 static int duplicate(struct range *, struct range *);
134 static int edit(struct diff *, int, int);
135 static char *getchange(FILE *);
136 static char *get_line(FILE *, size_t *);
137 static int number(char **);
138 static size_t readin(int, struct diff **);
139 static int skip(int, int, char *);
140 static int edscript(int);
141 static int merge(size_t, size_t);
142 static void change(int, struct range *, int);
143 static void keep(int, struct range *);
144 static void prange(struct range *);
145 static void repos(int);
146 static void separate(const char *);
147 static void increase(void);
148 static int diff3_internal(int, char **, const char *, const char *);
149
150 int diff3_conflicts = 0;
151 RCSNUM *d3rev1 = NULL;
152 RCSNUM *d3rev2 = NULL;
153
154 static int fds[5];
155
156 void
cvs_merge_file(struct cvs_file * cf,int verbose)157 cvs_merge_file(struct cvs_file *cf, int verbose)
158 {
159 int i, argc;
160 char *data, *patch;
161 char *argv[5], r1[CVS_REV_BUFSZ], r2[CVS_REV_BUFSZ];
162 char *dp13, *dp23, *path1, *path2, *path3;
163 BUF *b1, *d1, *d2, *diffb;
164 size_t dlen, plen;
165 struct rcs_line *lp;
166 struct rcs_lines *dlines, *plines;
167
168 overlapcnt = 0;
169 b1 = d1 = d2 = diffb = NULL;
170
171 rcsnum_tostr(d3rev1, r1, sizeof(r1));
172 rcsnum_tostr(d3rev2, r2, sizeof(r2));
173
174 b1 = buf_load_fd(cf->fd);
175 d1 = buf_alloc(128);
176 d2 = buf_alloc(128);
177 diffb = buf_alloc(128);
178
179 (void)xasprintf(&path1, "%s/diff1.XXXXXXXXXX", cvs_tmpdir);
180 (void)xasprintf(&path2, "%s/diff2.XXXXXXXXXX", cvs_tmpdir);
181 (void)xasprintf(&path3, "%s/diff3.XXXXXXXXXX", cvs_tmpdir);
182
183 fds[2] = buf_write_stmp(b1, path1, NULL);
184 if (verbose == 1)
185 cvs_printf("Retrieving revision %s\n", r1);
186 fds[3] = rcs_rev_write_stmp(cf->file_rcs, d3rev1, path2, 0);
187 if (verbose == 1)
188 cvs_printf("Retrieving revision %s\n", r2);
189 fds[4] = rcs_rev_write_stmp(cf->file_rcs, d3rev2, path3, 0);
190
191 diffreg(path1, path3, fds[2], fds[4], d1, D_FORCEASCII);
192 diffreg(path2, path3, fds[3], fds[4], d2, D_FORCEASCII);
193
194 (void)xasprintf(&dp13, "%s/d13.XXXXXXXXXX", cvs_tmpdir);
195 fds[0] = buf_write_stmp(d1, dp13, NULL);
196 buf_free(d1);
197
198 (void)xasprintf(&dp23, "%s/d23.XXXXXXXXXX", cvs_tmpdir);
199 fds[1] = buf_write_stmp(d2, dp23, NULL);
200 buf_free(d2);
201
202 argc = 0;
203 diffbuf = diffb;
204 argv[argc++] = dp13;
205 argv[argc++] = dp23;
206 argv[argc++] = path1;
207 argv[argc++] = path2;
208 argv[argc++] = path3;
209
210 if (lseek(fds[2], 0, SEEK_SET) == -1)
211 fatal("cvs_merge_file: lseek fds[2]: %s", strerror(errno));
212 if (lseek(fds[3], 0, SEEK_SET) == -1)
213 fatal("cvs_merge_file: lseek fds[3]: %s", strerror(errno));
214 if (lseek(fds[4], 0, SEEK_SET) == -1)
215 fatal("cvs_merge_file: lseek fds[4]: %s", strerror(errno));
216
217 diff3_conflicts = diff3_internal(argc, argv, cf->file_path, r2);
218 if (diff3_conflicts < 0)
219 fatal("cvs_merge_file: merging failed for an unknown reason");
220
221 plen = buf_len(diffb);
222 patch = buf_release(diffb);
223 dlen = buf_len(b1);
224 data = buf_release(b1);
225
226 if (verbose == 1)
227 cvs_printf("Merging differences between %s and %s into `%s'\n",
228 r1, r2, cf->file_path);
229
230 dlines = cvs_splitlines(data, dlen);
231 plines = cvs_splitlines(patch, plen);
232
233 ed_patch_lines(dlines, plines);
234 cvs_freelines(plines);
235
236 if (verbose == 1 && diff3_conflicts != 0) {
237 cvs_log(LP_ERR, "%d conflict%s found during merge, "
238 "please correct.", diff3_conflicts,
239 (diff3_conflicts > 1) ? "s" : "");
240 }
241
242 (void)close(cf->fd);
243 cf->fd = open(cf->file_path, O_CREAT | O_RDWR | O_TRUNC, 0644);
244 if (cf->fd == -1) {
245 fatal("cvs_merge_file: failed to reopen fd for writing: %s",
246 strerror(errno));
247 }
248
249 TAILQ_FOREACH(lp, &(dlines->l_lines), l_list) {
250 if (lp->l_line == NULL)
251 continue;
252
253 if (atomicio(vwrite, cf->fd, lp->l_line, lp->l_len) !=
254 lp->l_len)
255 fatal("cvs_merge_file: %s", strerror(errno));
256 }
257
258 cvs_freelines(dlines);
259
260 free(data);
261 free(patch);
262
263 for (i = 0; i < 3; i++)
264 fclose(fp[i]);
265
266 worklist_run(&temp_files, worklist_unlink);
267
268 free(path1);
269 free(path2);
270 free(path3);
271 free(dp13);
272 free(dp23);
273 }
274
275 static int
diff3_internal(int argc,char ** argv,const char * fmark,const char * rmark)276 diff3_internal(int argc, char **argv, const char *fmark, const char *rmark)
277 {
278 size_t m, n;
279 int i;
280
281 eflag = 3;
282 oflag = 1;
283
284 if (argc < 5)
285 return (-1);
286
287 (void)xsnprintf(f1mark, sizeof(f1mark), "<<<<<<< %s", fmark);
288 (void)xsnprintf(f3mark, sizeof(f3mark), ">>>>>>> %s", rmark);
289
290 szchanges = 0;
291 memset(last, 0, sizeof(last));
292 memset(cline, 0, sizeof(cline));
293 free(d13);
294 free(d23);
295 free(overlap);
296 free(de);
297
298 de = d13 = d23 = NULL;
299 overlap = NULL;
300
301 increase();
302
303 /* fds[0] and fds[1] are closed in readin() */
304 m = readin(fds[0], &d13);
305 n = readin(fds[1], &d23);
306
307 for (i = 0; i <= 2; i++) {
308 if ((fp[i] = fdopen(fds[i + 2], "r")) == NULL) {
309 cvs_log(LP_ERR, "%s", argv[i + 2]);
310 return (-1);
311 }
312 }
313
314 return (merge(m, n));
315 }
316
317 int
ed_patch_lines(struct rcs_lines * dlines,struct rcs_lines * plines)318 ed_patch_lines(struct rcs_lines *dlines, struct rcs_lines *plines)
319 {
320 char op, *ep;
321 struct rcs_line *sort, *lp, *dlp, *ndlp, *insert_after;
322 int start, end, i, lineno;
323 u_char tmp;
324
325 dlp = TAILQ_FIRST(&(dlines->l_lines));
326 lp = TAILQ_FIRST(&(plines->l_lines));
327
328 end = 0;
329 for (lp = TAILQ_NEXT(lp, l_list); lp != NULL;
330 lp = TAILQ_NEXT(lp, l_list)) {
331 /* Skip blank lines */
332 if (lp->l_len < 2)
333 continue;
334
335 /* NUL-terminate line buffer for strtol() safety. */
336 tmp = lp->l_line[lp->l_len - 1];
337 lp->l_line[lp->l_len - 1] = '\0';
338
339 op = lp->l_line[strlen(lp->l_line) - 1];
340 start = (int)strtol(lp->l_line, &ep, 10);
341
342 /* Restore the last byte of the buffer */
343 lp->l_line[lp->l_len - 1] = tmp;
344
345 if (op == 'a') {
346 if (start > dlines->l_nblines ||
347 start < 0 || *ep != 'a')
348 fatal("ed_patch_lines %d", start);
349 } else if (op == 'c') {
350 if (start > dlines->l_nblines ||
351 start < 0 || (*ep != ',' && *ep != 'c'))
352 fatal("ed_patch_lines");
353
354 if (*ep == ',') {
355 ep++;
356 end = (int)strtol(ep, &ep, 10);
357 if (end < 0 || *ep != 'c')
358 fatal("ed_patch_lines");
359 } else {
360 end = start;
361 }
362 } else {
363 fatal("invalid op %c found while merging", op);
364 }
365
366
367 for (;;) {
368 if (dlp == NULL)
369 break;
370 if (dlp->l_lineno == start)
371 break;
372 if (dlp->l_lineno > start) {
373 dlp = TAILQ_PREV(dlp, tqh, l_list);
374 } else if (dlp->l_lineno < start) {
375 ndlp = TAILQ_NEXT(dlp, l_list);
376 if (ndlp->l_lineno > start)
377 break;
378 dlp = ndlp;
379 }
380 }
381
382 if (dlp == NULL)
383 fatal("ed_patch_lines");
384
385
386 if (op == 'c') {
387 insert_after = TAILQ_PREV(dlp, tqh, l_list);
388 for (i = 0; i <= (end - start); i++) {
389 ndlp = TAILQ_NEXT(dlp, l_list);
390 TAILQ_REMOVE(&(dlines->l_lines), dlp, l_list);
391 dlp = ndlp;
392 }
393 dlp = insert_after;
394 }
395
396 if (op == 'a' || op == 'c') {
397 for (;;) {
398 ndlp = lp;
399 lp = TAILQ_NEXT(lp, l_list);
400 if (lp == NULL)
401 fatal("ed_patch_lines");
402
403 if (lp->l_len == 2 &&
404 lp->l_line[0] == '.' &&
405 lp->l_line[1] == '\n')
406 break;
407
408 TAILQ_REMOVE(&(plines->l_lines), lp, l_list);
409 TAILQ_INSERT_AFTER(&(dlines->l_lines), dlp,
410 lp, l_list);
411 dlp = lp;
412
413 lp->l_lineno = start;
414 lp = ndlp;
415 }
416 }
417
418 /*
419 * always resort lines as the markers might be put at the
420 * same line as we first started editing.
421 */
422 lineno = 0;
423 TAILQ_FOREACH(sort, &(dlines->l_lines), l_list)
424 sort->l_lineno = lineno++;
425 dlines->l_nblines = lineno - 1;
426 }
427
428 return (0);
429 }
430
431 /*
432 * Pick up the line numbers of all changes from one change file.
433 * (This puts the numbers in a vector, which is not strictly necessary,
434 * since the vector is processed in one sequential pass.
435 * The vector could be optimized out of existence)
436 */
437 static size_t
readin(int fd,struct diff ** dd)438 readin(int fd, struct diff **dd)
439 {
440 int a, b, c, d;
441 char kind, *p;
442 size_t i;
443
444 fp[0] = fdopen(fd, "r");
445 if (fp[0] == NULL)
446 fatal("readin: fdopen: %s", strerror(errno));
447
448 for (i = 0; (p = getchange(fp[0])); i++) {
449 if (i >= szchanges - 1)
450 increase();
451 a = b = number(&p);
452 if (*p == ',') {
453 p++;
454 b = number(&p);
455 }
456 kind = *p++;
457 c = d = number(&p);
458 if (*p==',') {
459 p++;
460 d = number(&p);
461 }
462 if (kind == 'a')
463 a++;
464 if (kind == 'd')
465 c++;
466 b++;
467 d++;
468 (*dd)[i].old.from = a;
469 (*dd)[i].old.to = b;
470 (*dd)[i].new.from = c;
471 (*dd)[i].new.to = d;
472 }
473
474 if (i) {
475 (*dd)[i].old.from = (*dd)[i-1].old.to;
476 (*dd)[i].new.from = (*dd)[i-1].new.to;
477 }
478
479 (void)fclose(fp[0]);
480
481 return (i);
482 }
483
484 static int
number(char ** lc)485 number(char **lc)
486 {
487 int nn;
488
489 nn = 0;
490 while (isdigit((unsigned char)(**lc)))
491 nn = nn*10 + *(*lc)++ - '0';
492
493 return (nn);
494 }
495
496 static char *
getchange(FILE * b)497 getchange(FILE *b)
498 {
499 char *line;
500
501 while ((line = get_line(b, NULL))) {
502 if (isdigit((unsigned char)line[0]))
503 return (line);
504 }
505
506 return (NULL);
507 }
508
509 static char *
get_line(FILE * b,size_t * n)510 get_line(FILE *b, size_t *n)
511 {
512 char *cp;
513 size_t len;
514 static char *buf;
515 static size_t bufsize;
516
517 if ((cp = fgetln(b, &len)) == NULL)
518 return (NULL);
519
520 if (cp[len - 1] != '\n')
521 len++;
522 if (len + 1 > bufsize) {
523 do {
524 bufsize += 1024;
525 } while (len + 1 > bufsize);
526 buf = xreallocarray(buf, 1, bufsize);
527 }
528 memcpy(buf, cp, len - 1);
529 buf[len - 1] = '\n';
530 buf[len] = '\0';
531 if (n != NULL)
532 *n = len;
533
534 return (buf);
535 }
536
537 static int
merge(size_t m1,size_t m2)538 merge(size_t m1, size_t m2)
539 {
540 struct diff *d1, *d2, *d3;
541 int dpl, j, t1, t2;
542
543 d1 = d13;
544 d2 = d23;
545 j = 0;
546 for (;;) {
547 t1 = (d1 < d13 + m1);
548 t2 = (d2 < d23 + m2);
549 if (!t1 && !t2)
550 break;
551
552 if (debug) {
553 printf("%d,%d=%d,%d %d,%d=%d,%d\n",
554 d1->old.from, d1->old.to,
555 d1->new.from, d1->new.to,
556 d2->old.from, d2->old.to,
557 d2->new.from, d2->new.to);
558 }
559
560 /* first file is different from others */
561 if (!t2 || (t1 && d1->new.to < d2->new.from)) {
562 /* stuff peculiar to 1st file */
563 if (eflag==0) {
564 separate("1");
565 change(1, &d1->old, 0);
566 keep(2, &d1->new);
567 change(3, &d1->new, 0);
568 }
569 d1++;
570 continue;
571 }
572
573 /* second file is different from others */
574 if (!t1 || (t2 && d2->new.to < d1->new.from)) {
575 if (eflag==0) {
576 separate("2");
577 keep(1, &d2->new);
578 change(2, &d2->old, 0);
579 change(3, &d2->new, 0);
580 }
581 d2++;
582 continue;
583 }
584
585 /*
586 * Merge overlapping changes in first file
587 * this happens after extension (see below).
588 */
589 if (d1 + 1 < d13 + m1 && d1->new.to >= d1[1].new.from) {
590 d1[1].old.from = d1->old.from;
591 d1[1].new.from = d1->new.from;
592 d1++;
593 continue;
594 }
595
596 /* merge overlapping changes in second */
597 if (d2 + 1 < d23 + m2 && d2->new.to >= d2[1].new.from) {
598 d2[1].old.from = d2->old.from;
599 d2[1].new.from = d2->new.from;
600 d2++;
601 continue;
602 }
603 /* stuff peculiar to third file or different in all */
604 if (d1->new.from == d2->new.from && d1->new.to == d2->new.to) {
605 dpl = duplicate(&d1->old,&d2->old);
606 if (dpl == -1)
607 return (-1);
608
609 /*
610 * dpl = 0 means all files differ
611 * dpl = 1 means files 1 and 2 identical
612 */
613 if (eflag==0) {
614 separate(dpl ? "3" : "");
615 change(1, &d1->old, dpl);
616 change(2, &d2->old, 0);
617 d3 = d1->old.to > d1->old.from ? d1 : d2;
618 change(3, &d3->new, 0);
619 } else
620 j = edit(d1, dpl, j);
621 d1++;
622 d2++;
623 continue;
624 }
625
626 /*
627 * Overlapping changes from file 1 and 2; extend changes
628 * appropriately to make them coincide.
629 */
630 if (d1->new.from < d2->new.from) {
631 d2->old.from -= d2->new.from-d1->new.from;
632 d2->new.from = d1->new.from;
633 } else if (d2->new.from < d1->new.from) {
634 d1->old.from -= d1->new.from-d2->new.from;
635 d1->new.from = d2->new.from;
636 }
637 if (d1->new.to > d2->new.to) {
638 d2->old.to += d1->new.to - d2->new.to;
639 d2->new.to = d1->new.to;
640 } else if (d2->new.to > d1->new.to) {
641 d1->old.to += d2->new.to - d1->new.to;
642 d1->new.to = d2->new.to;
643 }
644 }
645
646 return (edscript(j));
647 }
648
649 static void
separate(const char * s)650 separate(const char *s)
651 {
652 diff_output("====%s\n", s);
653 }
654
655 /*
656 * The range of lines rold.from thru rold.to in file i is to be changed.
657 * It is to be printed only if it does not duplicate something to be
658 * printed later.
659 */
660 static void
change(int i,struct range * rold,int fdup)661 change(int i, struct range *rold, int fdup)
662 {
663 diff_output("%d:", i);
664 last[i] = rold->to;
665 prange(rold);
666 if (fdup || debug)
667 return;
668 i--;
669 (void)skip(i, rold->from, NULL);
670 (void)skip(i, rold->to, " ");
671 }
672
673 /*
674 * print the range of line numbers, rold.from thru rold.to, as n1,n2 or n1
675 */
676 static void
prange(struct range * rold)677 prange(struct range *rold)
678 {
679 if (rold->to <= rold->from)
680 diff_output("%da\n", rold->from - 1);
681 else {
682 diff_output("%d", rold->from);
683 if (rold->to > rold->from+1)
684 diff_output(",%d", rold->to - 1);
685 diff_output("c\n");
686 }
687 }
688
689 /*
690 * No difference was reported by diff between file 1 (or 2) and file 3,
691 * and an artificial dummy difference (trange) must be ginned up to
692 * correspond to the change reported in the other file.
693 */
694 static void
keep(int i,struct range * rnew)695 keep(int i, struct range *rnew)
696 {
697 int delta;
698 struct range trange;
699
700 delta = last[3] - last[i];
701 trange.from = rnew->from - delta;
702 trange.to = rnew->to - delta;
703 change(i, &trange, 1);
704 }
705
706 /*
707 * skip to just before line number from in file "i". If "pr" is non-NULL,
708 * print all skipped stuff with string pr as a prefix.
709 */
710 static int
skip(int i,int from,char * pr)711 skip(int i, int from, char *pr)
712 {
713 size_t j, n;
714 char *line;
715
716 for (n = 0; cline[i] < from - 1; n += j) {
717 if ((line = get_line(fp[i], &j)) == NULL)
718 return (-1);
719 if (pr != NULL)
720 diff_output("%s%s", pr, line);
721 cline[i]++;
722 }
723 return ((int) n);
724 }
725
726 /*
727 * Return 1 or 0 according as the old range (in file 1) contains exactly
728 * the same data as the new range (in file 2).
729 */
730 static int
duplicate(struct range * r1,struct range * r2)731 duplicate(struct range *r1, struct range *r2)
732 {
733 int c,d;
734 int nchar;
735 int nline;
736
737 if (r1->to-r1->from != r2->to-r2->from)
738 return (0);
739 (void)skip(0, r1->from, NULL);
740 (void)skip(1, r2->from, NULL);
741 nchar = 0;
742 for (nline=0; nline < r1->to - r1->from; nline++) {
743 do {
744 c = getc(fp[0]);
745 d = getc(fp[1]);
746 if (c == -1 && d == -1)
747 break;
748 if (c == -1 || d== -1)
749 return (-1);
750 nchar++;
751 if (c != d) {
752 repos(nchar);
753 return (0);
754 }
755 } while (c != '\n');
756 }
757 repos(nchar);
758 return (1);
759 }
760
761 static void
repos(int nchar)762 repos(int nchar)
763 {
764 int i;
765
766 for (i = 0; i < 2; i++)
767 (void)fseek(fp[i], (long)-nchar, SEEK_CUR);
768 }
769
770 /*
771 * collect an editing script for later regurgitation
772 */
773 static int
edit(struct diff * diff,int fdup,int j)774 edit(struct diff *diff, int fdup, int j)
775 {
776 if (((fdup + 1) & eflag) == 0)
777 return (j);
778 j++;
779 overlap[j] = !fdup;
780 if (!fdup)
781 overlapcnt++;
782 de[j].old.from = diff->old.from;
783 de[j].old.to = diff->old.to;
784 de[j].new.from = de[j-1].new.to + skip(2, diff->new.from, NULL);
785 de[j].new.to = de[j].new.from + skip(2, diff->new.to, NULL);
786 return (j);
787 }
788
789 /* regurgitate */
790 static int
edscript(int n)791 edscript(int n)
792 {
793 int j, k;
794 char block[BUFSIZ+1];
795
796 for (; n > 0; n--) {
797 if (!oflag || !overlap[n])
798 prange(&de[n].old);
799 else
800 diff_output("%da\n=======\n", de[n].old.to -1);
801 (void)fseek(fp[2], (long)de[n].new.from, SEEK_SET);
802 for (k = de[n].new.to-de[n].new.from; k > 0; k-= j) {
803 size_t r;
804 j = k > BUFSIZ ? BUFSIZ : k;
805 r = fread(block, 1, j, fp[2]);
806 if (r == 0) {
807 if (feof(fp[2]))
808 break;
809 return (-1);
810 }
811 if (r != (size_t)j)
812 j = r;
813 block[j] = '\0';
814 diff_output("%s", block);
815 }
816
817 if (!oflag || !overlap[n])
818 diff_output(".\n");
819 else {
820 diff_output("%s\n.\n", f3mark);
821 diff_output("%da\n%s\n.\n", de[n].old.from - 1, f1mark);
822 }
823 }
824
825 return (overlapcnt);
826 }
827
828 static void
increase(void)829 increase(void)
830 {
831 size_t newsz, incr;
832
833 /* are the memset(3) calls needed? */
834 newsz = szchanges == 0 ? 64 : 2 * szchanges;
835 incr = newsz - szchanges;
836
837 d13 = xreallocarray(d13, newsz, sizeof(*d13));
838 memset(d13 + szchanges, 0, incr * sizeof(*d13));
839 d23 = xreallocarray(d23, newsz, sizeof(*d23));
840 memset(d23 + szchanges, 0, incr * sizeof(*d23));
841 de = xreallocarray(de, newsz, sizeof(*de));
842 memset(de + szchanges, 0, incr * sizeof(*de));
843 overlap = xreallocarray(overlap, newsz, sizeof(*overlap));
844 memset(overlap + szchanges, 0, incr * sizeof(*overlap));
845 szchanges = newsz;
846 }
847