op public repos

Blob

Date:: Mon Oct 21 10:53:42 2019 UTC
Message:: fix build on sparc64 (uninitialized variable)
Actions:: History | Blame | Raw File
1 /*	$OpenBSD: diff3.c,v 1.41 2016/10/18 21:06:52 millert 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 <sys/stat.h>
68 #include <sys/queue.h>
69 
70 #include <ctype.h>
71 #include <limits.h>
72 #include <stdio.h>
73 #include <stdarg.h>
74 #include <stdlib.h>
75 #include <string.h>
76 #include <time.h>
77 #include <unistd.h>
78 
79 #include "got_error.h"
80 #include "got_opentemp.h"
81 #include "got_object.h"
82 
83 #include "buf.h"
84 #include "rcsutil.h"
85 #include "got_lib_diff.h"
86 
87 #ifndef nitems
88 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
89 #endif
90 
91 /* diff3 - 3-way differential file comparison */
92 
93 /* diff3 [-ex3EX] d13 d23 f1 f2 f3 [m1 m3]
94  *
95  * d13 = diff report on f1 vs f3
96  * d23 = diff report on f2 vs f3
97  * f1, f2, f3 the 3 files
98  * if changes in f1 overlap with changes in f3, m1 and m3 are used
99  * to mark the overlaps; otherwise, the file names f1 and f3 are used
100  * (only for options E and X).
101  */
102 
103 /*
104  * "from" is first in range of changed lines; "to" is last+1
105  * from=to=line after point of insertion for added lines.
106  */
107 struct line_range {
108 	int from;
109 	int to;
110 };
111 
112 struct off_range {
113 	off_t from;
114 	off_t to;
115 };
116 
117 struct diff {
118 	struct line_range old;
119 	struct line_range new;
120 	struct off_range oldo;
121 	struct off_range newo;
122 };
123 
124 struct diff3_state {
125 	size_t szchanges;
126 
127 	struct diff *d13;
128 	struct diff *d23;
129 
130 	/*
131 	 * "de" is used to gather editing scripts.  These are later spewed out
132 	 * in reverse order.  Its first element must be all zero, the "new"
133 	 * component of "de" contains line positions, and "oldo" and "newo"
134 	 * components contain byte positions.
135 	 * Array overlap indicates which sections in "de" correspond to lines
136 	 * that are different in all three files.
137 	 */
138 	struct diff *de;
139 	char *overlap;
140 	int overlapcnt;
141 	FILE *fp[3];
142 	int cline[3];		/* # of the last-read line in each file (0-2) */
143 
144 	/*
145 	 * the latest known correspondence between line numbers of the 3 files
146 	 * is stored in last[1-3];
147 	 */
148 	int last[4];
149 	char f1mark[PATH_MAX];
150 	char f2mark[PATH_MAX];
151 	char f3mark[PATH_MAX];
152 
153 	char *buf;
154 
155 	BUF *diffbuf;
156 };
157 
158 
159 static const struct got_error *duplicate(int *, int, struct line_range *,
160     struct line_range *, struct diff3_state *);
161 static const struct got_error *edit(struct diff *, int, int *,
162     struct diff3_state *);
163 static const struct got_error *getchange(char **, FILE *, struct diff3_state *);
164 static const struct got_error *get_line(char **, FILE *, size_t *,
165     struct diff3_state *);
166 static int number(char **);
167 static const struct got_error *readin(size_t *, char *, struct diff **,
168     struct diff3_state *);
169 static int ed_patch_lines(struct rcs_lines *, struct rcs_lines *);
170 static const struct got_error *skip(size_t *, int, int, struct diff3_state *);
171 static const struct got_error *edscript(int, struct diff3_state *);
172 static const struct got_error *merge(size_t, size_t, struct diff3_state *);
173 static const struct got_error *prange(struct line_range *, struct diff3_state *);
174 static const struct got_error *repos(int, struct diff3_state *);
175 static const struct got_error *increase(struct diff3_state *);
176 static const struct got_error *diff3_internal(char *, char *, char *,
177     char *, char *, const char *, const char *, struct diff3_state *,
178     const char *, const char *, const char *);
179 
180 static const struct got_error *
181 diff_output(BUF *diffbuf, const char *fmt, ...)
182 {
183 	const struct got_error *err = NULL;
184 	va_list vap;
185 	int i;
186 	char *str;
187 	size_t newsize;
188 
189 	va_start(vap, fmt);
190 	i = vasprintf(&str, fmt, vap);
191 	va_end(vap);
192 	if (i == -1)
193 		return got_error_from_errno("vasprintf");
194 	err = buf_append(&newsize, diffbuf, str, strlen(str));
195 	free(str);
196 	return err;
197 }
198 
199 static const struct got_error*
200 diffreg(BUF **d, const char *path1, const char *path2)
201 {
202 	const struct got_error *err = NULL;
203 	FILE *f1 = NULL, *f2 = NULL, *outfile = NULL;
204 	char *outpath = NULL;
205 	struct got_diff_state ds;
206 	struct got_diff_args args;
207 	int res;
208 
209 	*d = NULL;
210 
211 	f1 = fopen(path1, "r");
212 	if (f1 == NULL) {
213 		err = got_error_from_errno2("fopen", path1);
214 		goto done;
215 	}
216 	f2 = fopen(path2, "r");
217 	if (f1 == NULL) {
218 		err = got_error_from_errno2("fopen", path2);
219 		goto done;
220 	}
221 
222 	err = got_opentemp_named(&outpath, &outfile, "/tmp/got-diffreg");
223 	if (err)
224 		goto done;
225 
226 	memset(&ds, 0, sizeof(ds));
227 	/* XXX should stat buffers be passed in args instead of ds? */
228 	if (stat(path1, &ds.stb1) == -1) {
229 		err = got_error_from_errno2("stat", path1);
230 		goto done;
231 	}
232 	if (stat(path2, &ds.stb2) == -1) {
233 		err = got_error_from_errno2("stat", path2);
234 		goto done;
235 	}
236 
237 	memset(&args, 0, sizeof(args));
238 	args.diff_format = D_NORMAL;
239 	args.label[0] = "";
240 	args.label[1] = "";
241 	args.diff_context = 0;
242 
243 	err = got_diffreg(&res, f1, f2, D_FORCEASCII, &args, &ds,
244 	    outfile, NULL);
245 	if (err)
246 		goto done;
247 
248 	if (fflush(outfile) != 0) {
249 		err = got_error_from_errno2("fflush", outpath);
250 		goto done;
251 	}
252 
253 	err = buf_load(d, outpath);
254 done:
255 	if (outpath) {
256 		if (unlink(outpath) == -1 && err == NULL)
257 			err = got_error_from_errno2("unlink", outpath);
258 		free(outpath);
259 	}
260 	if (outfile && fclose(outfile) != 0 && err == NULL)
261 		err = got_error_from_errno("fclose");
262 	if (f1 && fclose(f1) != 0 && err == NULL)
263 		err = got_error_from_errno("fclose");
264 	if (f2 && fclose(f2) != 0 && err == NULL)
265 		err = got_error_from_errno("fclose");
266 	return err;
267 }
268 
269 /*
270  * For merge(1).
271  */
272 const struct got_error *
273 got_merge_diff3(int *overlapcnt, int outfd, const char *p1, const char *p2,
274     const char *p3, const char *label1, const char *label2, const char *label3)
275 {
276 	const struct got_error *err = NULL;
277 	char *dp13, *dp23, *path1, *path2, *path3;
278 	BUF *b1, *b2, *b3, *d1, *d2, *diffb;
279 	u_char *data, *patch;
280 	size_t dlen, plen;
281 	struct diff3_state *d3s;
282 	int i;
283 
284 	*overlapcnt = 0;
285 
286 	d3s = calloc(1, sizeof(*d3s));
287 	if (d3s == NULL)
288 		return got_error_from_errno("calloc");
289 
290 	b1 = b2 = b3 = d1 = d2 = diffb = NULL;
291 	dp13 = dp23 = path1 = path2 = path3 = NULL;
292 	data = patch = NULL;
293 
294 	err = buf_load(&b1, p1);
295 	if (err)
296 		goto out;
297 	err = buf_load(&b2, p2);
298 	if (err)
299 		goto out;
300 	err = buf_load(&b3, p3);
301 	if (err)
302 		goto out;
303 
304 	err = buf_alloc(&diffb, 128);
305 	if (err)
306 		goto out;
307 
308 	if (asprintf(&path1, "/tmp/got-diff1.XXXXXXXX") == -1) {
309 		err = got_error_from_errno("asprintf");
310 		goto out;
311 	}
312 	if (asprintf(&path2, "/tmp/got-diff2.XXXXXXXX") == -1) {
313 		err = got_error_from_errno("asprintf");
314 		goto out;
315 	}
316 	if (asprintf(&path3, "/tmp/got-diff3.XXXXXXXX") == -1) {
317 		err = got_error_from_errno("asprintf");
318 		goto out;
319 	}
320 
321 	err = buf_write_stmp(b1, path1);
322 	if (err)
323 		goto out;
324 	err = buf_write_stmp(b2, path2);
325 	if (err)
326 		goto out;
327 	err = buf_write_stmp(b3, path3);
328 	if (err)
329 		goto out;
330 
331 	buf_free(b2);
332 	b2 = NULL;
333 
334 	err = diffreg(&d1, path1, path3);
335 	if (err) {
336 		buf_free(diffb);
337 		diffb = NULL;
338 		goto out;
339 
340 	}
341 	err = diffreg(&d2, path2, path3);
342 	if (err) {
343 		buf_free(diffb);
344 		diffb = NULL;
345 		goto out;
346 	}
347 
348 	if (asprintf(&dp13, "/tmp/got-d13.XXXXXXXXXX") == -1) {
349 		err = got_error_from_errno("asprintf");
350 		goto out;
351 	}
352 	err = buf_write_stmp(d1, dp13);
353 	if (err)
354 		goto out;
355 
356 	buf_free(d1);
357 	d1 = NULL;
358 
359 	if (asprintf(&dp23, "/tmp/got-d23.XXXXXXXXXX") == -1) {
360 		err = got_error_from_errno("asprintf");
361 		goto out;
362 	}
363 	err = buf_write_stmp(d2, dp23);
364 	if (err)
365 		goto out;
366 
367 	buf_free(d2);
368 	d2 = NULL;
369 
370 	d3s->diffbuf = diffb;
371 	err = diff3_internal(dp13, dp23, path1, path2, path3,
372 	    label1, label3, d3s, label1, label2, label3);
373 	if (err) {
374 		buf_free(diffb);
375 		diffb = NULL;
376 		goto out;
377 	}
378 
379 	plen = buf_len(diffb);
380 	patch = buf_release(diffb);
381 	dlen = buf_len(b1);
382 	data = buf_release(b1);
383 
384 	diffb = rcs_patchfile(data, dlen, patch, plen, ed_patch_lines);
385 out:
386 	buf_free(b2);
387 	buf_free(b3);
388 	buf_free(d1);
389 	buf_free(d2);
390 
391 	if (unlink(path1) == -1 && err == NULL)
392 		err = got_error_from_errno2("unlink", path1);
393 	if (unlink(path2) == -1 && err == NULL)
394 		err = got_error_from_errno2("unlink", path2);
395 	if (unlink(path3) == -1 && err == NULL)
396 		err = got_error_from_errno2("unlink", path3);
397 	if (unlink(dp13) == -1 && err == NULL)
398 		err = got_error_from_errno2("unlink", dp13);
399 	if (unlink(dp23) == -1 && err == NULL)
400 		err = got_error_from_errno2("unlink", dp23);
401 
402 	free(path1);
403 	free(path2);
404 	free(path3);
405 	free(dp13);
406 	free(dp23);
407 	free(data);
408 	free(patch);
409 
410 	for (i = 0; i < nitems(d3s->fp); i++) {
411 		if (d3s->fp[i] && fclose(d3s->fp[i]) != 0 && err == NULL)
412 			err = got_error_from_errno("fclose");
413 	}
414 	if (err == NULL && diffb) {
415 		if (buf_write_fd(diffb, outfd) < 0)
416 			err = got_error_from_errno("buf_write_fd");
417 		*overlapcnt = d3s->overlapcnt;
418 	}
419 	free(d3s);
420 	buf_free(diffb);
421 	return err;
422 }
423 
424 static const struct got_error *
425 diff3_internal(char *dp13, char *dp23, char *path1, char *path2, char *path3,
426     const char *fmark, const char *rmark, struct diff3_state *d3s,
427     const char *label1, const char *label2, const char *label3)
428 {
429 	const struct got_error *err = NULL;
430 	ssize_t m, n;
431 	int i;
432 
433 	i = snprintf(d3s->f1mark, sizeof(d3s->f1mark),
434 	    "%s%s%s", GOT_DIFF_CONFLICT_MARKER_BEGIN,
435 	    label1 ? " " : "", label1 ? label1 : "");
436 	if (i < 0 || i >= (int)sizeof(d3s->f1mark))
437 		return got_error(GOT_ERR_NO_SPACE);
438 
439 	i = snprintf(d3s->f2mark, sizeof(d3s->f2mark),
440 	    "%s%s%s", GOT_DIFF_CONFLICT_MARKER_ORIG,
441 	    label2 ? " " : "", label2 ? label2 : "");
442 	if (i < 0 || i >= (int)sizeof(d3s->f2mark))
443 		return got_error(GOT_ERR_NO_SPACE);
444 
445 	i = snprintf(d3s->f3mark, sizeof(d3s->f3mark),
446 	    "%s%s%s", GOT_DIFF_CONFLICT_MARKER_END,
447 	    label3 ? " " : "", label3 ? label3 : "");
448 	if (i < 0 || i >= (int)sizeof(d3s->f3mark))
449 		return got_error(GOT_ERR_NO_SPACE);
450 
451 	err = increase(d3s);
452 	if (err)
453 		return err;
454 
455 	err = readin(&m, dp13, &d3s->d13, d3s);
456 	if (err)
457 		return err;
458 	err = readin(&n, dp23, &d3s->d23, d3s);
459 	if (err)
460 		return err;
461 
462 	if ((d3s->fp[0] = fopen(path1, "r")) == NULL)
463 		return got_error_from_errno2("fopen", path1);
464 	if ((d3s->fp[1] = fopen(path2, "r")) == NULL)
465 		return got_error_from_errno2("fopen", path2);
466 	if ((d3s->fp[2] = fopen(path3, "r")) == NULL)
467 		return got_error_from_errno2("fopen", path3);
468 
469 	return merge(m, n, d3s);
470 }
471 
472 static int
473 ed_patch_lines(struct rcs_lines *dlines, struct rcs_lines *plines)
474 {
475 	char op, *ep;
476 	struct rcs_line *sort, *lp, *dlp, *ndlp, *insert_after;
477 	int start, end, i, lineno;
478 	u_char tmp;
479 
480 	dlp = TAILQ_FIRST(&(dlines->l_lines));
481 	lp = TAILQ_FIRST(&(plines->l_lines));
482 
483 	end = 0;
484 	for (lp = TAILQ_NEXT(lp, l_list); lp != NULL;
485 	    lp = TAILQ_NEXT(lp, l_list)) {
486 		/* Skip blank lines */
487 		if (lp->l_len < 2)
488 			continue;
489 
490 		/* NUL-terminate line buffer for strtol() safety. */
491 		tmp = lp->l_line[lp->l_len - 1];
492 		lp->l_line[lp->l_len - 1] = '\0';
493 
494 		/* len - 1 is NUL terminator so we use len - 2 for 'op' */
495 		op = lp->l_line[lp->l_len - 2];
496 		start = (int)strtol(lp->l_line, &ep, 10);
497 
498 		/* Restore the last byte of the buffer */
499 		lp->l_line[lp->l_len - 1] = tmp;
500 
501 		if (op == 'a') {
502 			if (start > dlines->l_nblines ||
503 			    start < 0 || *ep != 'a')
504 				return -1;
505 		} else if (op == 'c') {
506 			if (start > dlines->l_nblines ||
507 			    start < 0 || (*ep != ',' && *ep != 'c'))
508 				return -1;
509 
510 			if (*ep == ',') {
511 				ep++;
512 				end = (int)strtol(ep, &ep, 10);
513 				if (end < 0 || *ep != 'c')
514 					return -1;
515 			} else {
516 				end = start;
517 			}
518 		}
519 
520 
521 		for (;;) {
522 			if (dlp == NULL)
523 				break;
524 			if (dlp->l_lineno == start)
525 				break;
526 			if (dlp->l_lineno > start) {
527 				dlp = TAILQ_PREV(dlp, tqh, l_list);
528 			} else if (dlp->l_lineno < start) {
529 				ndlp = TAILQ_NEXT(dlp, l_list);
530 				if (ndlp->l_lineno > start)
531 					break;
532 				dlp = ndlp;
533 			}
534 		}
535 
536 		if (dlp == NULL)
537 			return -1;
538 
539 
540 		if (op == 'c') {
541 			insert_after = TAILQ_PREV(dlp, tqh, l_list);
542 			for (i = 0; i <= (end - start); i++) {
543 				ndlp = TAILQ_NEXT(dlp, l_list);
544 				TAILQ_REMOVE(&(dlines->l_lines), dlp, l_list);
545 				dlp = ndlp;
546 			}
547 			dlp = insert_after;
548 		}
549 
550 		if (op == 'a' || op == 'c') {
551 			for (;;) {
552 				ndlp = lp;
553 				lp = TAILQ_NEXT(lp, l_list);
554 				if (lp == NULL)
555 					return -1;
556 
557 				if (lp->l_len == 2 &&
558 				    lp->l_line[0] == '.' &&
559 				    lp->l_line[1] == '\n')
560 					break;
561 
562 				TAILQ_REMOVE(&(plines->l_lines), lp, l_list);
563 				TAILQ_INSERT_AFTER(&(dlines->l_lines), dlp,
564 				    lp, l_list);
565 				dlp = lp;
566 
567 				lp->l_lineno = start;
568 				lp = ndlp;
569 			}
570 		}
571 
572 		/*
573 		 * always resort lines as the markers might be put at the
574 		 * same line as we first started editing.
575 		 */
576 		lineno = 0;
577 		TAILQ_FOREACH(sort, &(dlines->l_lines), l_list)
578 			sort->l_lineno = lineno++;
579 		dlines->l_nblines = lineno - 1;
580 	}
581 
582 	return (0);
583 }
584 
585 /*
586  * Pick up the line numbers of all changes from one change file.
587  * (This puts the numbers in a vector, which is not strictly necessary,
588  * since the vector is processed in one sequential pass.
589  * The vector could be optimized out of existence)
590  */
591 static const struct got_error *
592 readin(size_t *n, char *name, struct diff **dd, struct diff3_state *d3s)
593 {
594 	const struct got_error *err = NULL;
595 	FILE *f;
596 	int a, b, c, d;
597 	char kind, *p;
598 	size_t i = 0;
599 
600 	*n = 0;
601 
602 	f = fopen(name, "r");
603 	if (f == NULL)
604 		return got_error_from_errno2("fopen", name);
605 	err = getchange(&p, f, d3s);
606 	if (err)
607 		goto done;
608 	for (i = 0; p; i++) {
609 		if (i >= d3s->szchanges - 1) {
610 			err = increase(d3s);
611 			if (err)
612 				goto done;
613 		}
614 		a = b = number(&p);
615 		if (*p == ',') {
616 			p++;
617 			b = number(&p);
618 		}
619 		kind = *p++;
620 		c = d = number(&p);
621 		if (*p == ',') {
622 			p++;
623 			d = number(&p);
624 		}
625 		if (kind == 'a')
626 			a++;
627 		if (kind == 'd')
628 			c++;
629 		b++;
630 		d++;
631 		(*dd)[i].old.from = a;
632 		(*dd)[i].old.to = b;
633 		(*dd)[i].new.from = c;
634 		(*dd)[i].new.to = d;
635 
636 		err = getchange(&p, f, d3s);
637 		if (err)
638 			goto done;
639 	}
640 
641 	if (i) {
642 		(*dd)[i].old.from = (*dd)[i - 1].old.to;
643 		(*dd)[i].new.from = (*dd)[i - 1].new.to;
644 	}
645 done:
646 	if (fclose(f) != 0 && err == NULL)
647 		err = got_error_from_errno("fclose");
648 	if (err == NULL)
649 		*n = i;
650 	return err;
651 }
652 
653 static int
654 number(char **lc)
655 {
656 	int nn;
657 
658 	nn = 0;
659 	while (isdigit((unsigned char)(**lc)))
660 		nn = nn*10 + *(*lc)++ - '0';
661 
662 	return (nn);
663 }
664 
665 static const struct got_error *
666 getchange(char **line, FILE *b, struct diff3_state *d3s)
667 {
668 	const struct got_error *err = NULL;
669 
670 	*line = NULL;
671 	do {
672 		if (*line && isdigit((unsigned char)(*line)[0]))
673 			return NULL;
674 		err = get_line(line, b, NULL, d3s);
675 		if (err)
676 			return err;
677 	} while (*line);
678 
679 	return NULL;
680 }
681 
682 static const struct got_error *
683 get_line(char **ret, FILE *b, size_t *n, struct diff3_state *d3s)
684 {
685 	const struct got_error *err = NULL;
686 	char *cp = NULL;
687 	size_t size;
688 	ssize_t len;
689 	char *new;
690 
691 	*ret = NULL;
692 
693 	len = getline(&cp, &size, b);
694 	if (len == -1) {
695 		if (ferror(b))
696 			err = got_error_from_errno("getline");
697 		goto done;
698 	}
699 
700 	if (cp[len - 1] != '\n') {
701 		len++;
702 		if (len + 1 > size) {
703 			new = realloc(cp, len + 1);
704 			if (new == NULL) {
705 				err = got_error_from_errno("realloc");
706 				goto done;
707 			}
708 			cp = new;
709 		}
710 		cp[len - 1] = '\n';
711 		cp[len] = '\0';
712 	}
713 
714 	free(d3s->buf);
715 	*ret = d3s->buf = cp;
716 	cp = NULL;
717 	if (n != NULL)
718 		*n = len;
719 done:
720 	free(cp);
721 	return err;
722 }
723 
724 static const struct got_error *
725 merge(size_t m1, size_t m2, struct diff3_state *d3s)
726 {
727 	const struct got_error *err = NULL;
728 	struct diff *d1, *d2;
729 	int dpl, j, t1, t2;
730 
731 	d1 = d3s->d13;
732 	d2 = d3s->d23;
733 	j = 0;
734 	for (;;) {
735 		t1 = (d1 < d3s->d13 + m1);
736 		t2 = (d2 < d3s->d23 + m2);
737 		if (!t1 && !t2)
738 			break;
739 
740 		/* first file is different from others */
741 		if (!t2 || (t1 && d1->new.to < d2->new.from)) {
742 			/* stuff peculiar to 1st file */
743 			d1++;
744 			continue;
745 		}
746 
747 		/* second file is different from others */
748 		if (!t1 || (t2 && d2->new.to < d1->new.from)) {
749 			d2++;
750 			continue;
751 		}
752 
753 		/*
754 		 * Merge overlapping changes in first file
755 		 * this happens after extension (see below).
756 		 */
757 		if (d1 + 1 < d3s->d13 + m1 && d1->new.to >= d1[1].new.from) {
758 			d1[1].old.from = d1->old.from;
759 			d1[1].new.from = d1->new.from;
760 			d1++;
761 			continue;
762 		}
763 
764 		/* merge overlapping changes in second */
765 		if (d2 + 1 < d3s->d23 + m2 && d2->new.to >= d2[1].new.from) {
766 			d2[1].old.from = d2->old.from;
767 			d2[1].new.from = d2->new.from;
768 			d2++;
769 			continue;
770 		}
771 		/* stuff peculiar to third file or different in all */
772 		if (d1->new.from == d2->new.from && d1->new.to == d2->new.to) {
773 			err = duplicate(&dpl, j, &d1->old, &d2->old, d3s);
774 			if (err)
775 				return err;
776 
777 			/*
778 			 * dpl = 0 means all files differ
779 			 * dpl = 1 means files 1 and 2 identical
780 			 */
781 			err = edit(d1, dpl, &j, d3s);
782 			if (err)
783 				return err;
784 			d1++;
785 			d2++;
786 			continue;
787 		}
788 
789 		/*
790 		 * Overlapping changes from file 1 and 2; extend changes
791 		 * appropriately to make them coincide.
792 		 */
793 		if (d1->new.from < d2->new.from) {
794 			d2->old.from -= d2->new.from - d1->new.from;
795 			d2->new.from = d1->new.from;
796 		} else if (d2->new.from < d1->new.from) {
797 			d1->old.from -= d1->new.from - d2->new.from;
798 			d1->new.from = d2->new.from;
799 		}
800 		if (d1->new.to > d2->new.to) {
801 			d2->old.to += d1->new.to - d2->new.to;
802 			d2->new.to = d1->new.to;
803 		} else if (d2->new.to > d1->new.to) {
804 			d1->old.to += d2->new.to - d1->new.to;
805 			d1->new.to = d2->new.to;
806 		}
807 	}
808 
809 	return (edscript(j, d3s));
810 }
811 
812 /*
813  * print the range of line numbers, rold.from thru rold.to, as n1,n2 or n1
814  */
815 static const struct got_error *
816 prange(struct line_range *rold, struct diff3_state *d3s)
817 {
818 	const struct got_error *err = NULL;
819 
820 	if (rold->to <= rold->from) {
821 		err = diff_output(d3s->diffbuf, "%da\n", rold->from - 1);
822 		if (err)
823 			return err;
824 	} else {
825 		err = diff_output(d3s->diffbuf, "%d", rold->from);
826 		if (err)
827 			return err;
828 		if (rold->to > rold->from + 1) {
829 			err = diff_output(d3s->diffbuf, ",%d", rold->to - 1);
830 			if (err)
831 				return err;
832 		}
833 		err = diff_output(d3s->diffbuf, "c\n");
834 		if (err)
835 			return err;
836 	}
837 
838 	return NULL;
839 }
840 
841 /*
842  * Skip to just before line number from in file "i".
843  * Return the number of bytes skipped in *nskipped.
844  */
845 static const struct got_error *
846 skip(size_t *nskipped, int i, int from, struct diff3_state *d3s)
847 {
848 	const struct got_error *err = NULL;
849 	size_t len, n;
850 	char *line;
851 
852 	*nskipped = 0;
853 	for (n = 0; d3s->cline[i] < from - 1; n += len) {
854 		err = get_line(&line, d3s->fp[i], &len, d3s);
855 		if (err)
856 			return err;
857 		d3s->cline[i]++;
858 	}
859 	*nskipped = n;
860 	return NULL;
861 }
862 
863 /*
864  * Set *dpl to 1 or 0 according as the old range (in file 1) contains exactly
865  * the same data as the new range (in file 2).
866  *
867  * If this change could overlap, remember start/end offsets in file 2 so we
868  * can write out the original lines of text if a merge conflict occurs.
869  */
870 static const struct got_error *
871 duplicate(int *dpl, int j, struct line_range *r1, struct line_range *r2,
872     struct diff3_state *d3s)
873 {
874 	const struct got_error *err = NULL;
875 	int c,d;
876 	int nchar;
877 	int nline;
878 	size_t nskipped;
879 	off_t off;
880 
881 	*dpl = 0;
882 
883 	if (r1->to - r1->from != r2->to - r2->from)
884 		return NULL;
885 
886 	err = skip(&nskipped, 0, r1->from, d3s);
887 	if (err)
888 		return err;
889 	err = skip(&nskipped, 1, r2->from, d3s);
890 	if (err)
891 		return err;
892 
893 	off = ftello(d3s->fp[1]);
894 	if (off == -1)
895 		return got_error_from_errno("ftello");
896 	d3s->de[j + 1].oldo.from = off; /* original lines start here */
897 
898 	nchar = 0;
899 	for (nline = 0; nline < r1->to - r1->from; nline++) {
900 		do {
901 			c = getc(d3s->fp[0]);
902 			if (c == EOF)
903 				return got_ferror(d3s->fp[0], GOT_ERR_EOF);
904 			d = getc(d3s->fp[1]);
905 			if (d == EOF)
906 				return got_ferror(d3s->fp[1], GOT_ERR_EOF);
907 			nchar++;
908 			if (c != d) {
909 				long orig_line_len = nchar;
910 				while (d != '\n') {
911 					d = getc(d3s->fp[1]);
912 					if (d == EOF)
913 						break;
914 					orig_line_len++;
915 				}
916 				if (orig_line_len > nchar &&
917 				    fseek(d3s->fp[1], -(orig_line_len - nchar),
918 				    SEEK_CUR) == -1)
919 					return got_ferror(d3s->fp[1],
920 						GOT_ERR_IO);
921  				/* original lines end here */
922 				d3s->de[j + 1].oldo.to = off + orig_line_len;
923 				err = repos(nchar, d3s);
924 				if (err)
925 					return err;
926 				return NULL;
927 			}
928 		} while (c != '\n');
929 	}
930 	err = repos(nchar, d3s);
931 	if (err)
932 		return err;
933 	*dpl = 1;
934 	return NULL;
935 }
936 
937 static const struct got_error *
938 repos(int nchar, struct diff3_state *d3s)
939 {
940 	int i;
941 
942 	for (i = 0; i < 2; i++) {
943 		if (fseek(d3s->fp[i], (long)-nchar, SEEK_CUR) == -1)
944 			return got_ferror(d3s->fp[i], GOT_ERR_IO);
945 	}
946 
947 	return NULL;
948 }
949 
950 /*
951  * collect an editing script for later regurgitation
952  */
953 static const struct got_error *
954 edit(struct diff *diff, int fdup, int *j, struct diff3_state *d3s)
955 {
956 	const struct got_error *err = NULL;
957 	size_t nskipped;
958 
959 	if (((fdup + 1) & 3) == 0)
960 		return NULL;
961 	(*j)++;
962 	d3s->overlap[*j] = !fdup;
963 	if (!fdup)
964 		d3s->overlapcnt++;
965 	d3s->de[*j].old.from = diff->old.from;
966 	d3s->de[*j].old.to = diff->old.to;
967 
968 	err = skip(&nskipped, 2, diff->new.from, d3s);
969 	if (err)
970 		return err;
971 	d3s->de[*j].newo.from = d3s->de[*j - 1].newo.to + nskipped;
972 
973 	err = skip(&nskipped, 2, diff->new.to, d3s);
974 	if (err)
975 		return err;
976 	d3s->de[*j].newo.to = d3s->de[*j].newo.from + nskipped;
977 	return NULL;
978 }
979 
980 /* regurgitate */
981 static const struct got_error *
982 edscript(int n, struct diff3_state *d3s)
983 {
984 	const struct got_error *err = NULL;
985 	size_t k, len;
986 	char block[BUFSIZ+1];
987 
988 	for (; n > 0; n--) {
989 		if (!d3s->overlap[n]) {
990 			err = prange(&d3s->de[n].old, d3s);
991 			if (err)
992 				return err;
993 		} else if (d3s->de[n].oldo.from < d3s->de[n].oldo.to) {
994 			/* Output a block of 3-way diff base file content. */
995 			err = diff_output(d3s->diffbuf, "%da\n%s\n",
996 			    d3s->de[n].old.to - 1, d3s->f2mark);
997 			if (err)
998 				return err;
999 			if (fseeko(d3s->fp[1], d3s->de[n].oldo.from, SEEK_SET)
1000 			    == -1)
1001 				return got_error_from_errno("fseeko");
1002 			k = (size_t)(d3s->de[n].oldo.to - d3s->de[n].oldo.from);
1003 			for (; k > 0; k -= len) {
1004 				len = k > BUFSIZ ? BUFSIZ : k;
1005 				if (fread(block, 1, len, d3s->fp[1]) != len)
1006 					return got_ferror(d3s->fp[1],
1007 					    GOT_ERR_IO);
1008 				block[len] = '\0';
1009 				err = diff_output(d3s->diffbuf, "%s", block);
1010 				if (err)
1011 					return err;
1012 			}
1013 			err = diff_output(d3s->diffbuf, "%s\n",
1014 			    GOT_DIFF_CONFLICT_MARKER_SEP);
1015 			if (err)
1016 				return err;
1017  		} else {
1018  			err = diff_output(d3s->diffbuf, "%da\n%s\n",
1019 			    d3s->de[n].old.to -1, GOT_DIFF_CONFLICT_MARKER_SEP);
1020 			if (err)
1021 				return err;
1022 		}
1023 		if (fseeko(d3s->fp[2], d3s->de[n].newo.from, SEEK_SET)
1024 		    == -1)
1025 			return got_error_from_errno("fseek");
1026 		k = (size_t)(d3s->de[n].newo.to - d3s->de[n].newo.from);
1027 		for (; k > 0; k -= len) {
1028 			len = k > BUFSIZ ? BUFSIZ : k;
1029 			if (fread(block, 1, len, d3s->fp[2]) != len)
1030 				return got_ferror(d3s->fp[2], GOT_ERR_IO);
1031 			block[len] = '\0';
1032 			err = diff_output(d3s->diffbuf, "%s", block);
1033 			if (err)
1034 				return err;
1035 		}
1036 
1037 		if (!d3s->overlap[n]) {
1038 			err = diff_output(d3s->diffbuf, ".\n");
1039 			if (err)
1040 				return err;
1041 		} else {
1042 			err = diff_output(d3s->diffbuf, "%s\n.\n", d3s->f3mark);
1043 			if (err)
1044 				return err;
1045 			err = diff_output(d3s->diffbuf, "%da\n%s\n.\n",
1046 			    d3s->de[n].old.from - 1, d3s->f1mark);
1047 			if (err)
1048 				return err;
1049 		}
1050 	}
1051 
1052 	return NULL;
1053 }
1054 
1055 static const struct got_error *
1056 increase(struct diff3_state *d3s)
1057 {
1058 	size_t newsz, incr;
1059 	struct diff *d;
1060 	char *s;
1061 
1062 	/* are the memset(3) calls needed? */
1063 	newsz = d3s->szchanges == 0 ? 64 : 2 * d3s->szchanges;
1064 	incr = newsz - d3s->szchanges;
1065 
1066 	d = reallocarray(d3s->d13, newsz, sizeof(*d3s->d13));
1067 	if (d == NULL)
1068 		return got_error_from_errno("reallocarray");
1069 	d3s->d13 = d;
1070 	memset(d3s->d13 + d3s->szchanges, 0, incr * sizeof(*d3s->d13));
1071 
1072 	d = reallocarray(d3s->d23, newsz, sizeof(*d3s->d23));
1073 	if (d == NULL)
1074 		return got_error_from_errno("reallocarray");
1075 	d3s->d23 = d;
1076 	memset(d3s->d23 + d3s->szchanges, 0, incr * sizeof(*d3s->d23));
1077 
1078 	d = reallocarray(d3s->de, newsz, sizeof(*d3s->de));
1079 	if (d == NULL)
1080 		return got_error_from_errno("reallocarray");
1081 	d3s->de = d;
1082 	memset(d3s->de + d3s->szchanges, 0, incr * sizeof(*d3s->de));
1083 
1084 	s = reallocarray(d3s->overlap, newsz, sizeof(*d3s->overlap));
1085 	if (s == NULL)
1086 		return got_error_from_errno("reallocarray");
1087 	d3s->overlap = s;
1088 	memset(d3s->overlap + d3s->szchanges, 0, incr * sizeof(*d3s->overlap));
1089 	d3s->szchanges = newsz;
1090 
1091 	return NULL;
1092 }