1 /* $OpenBSD: diff3.c,v 1.59 2015/11/05 09:48:21 nicm 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 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) < 0) 211 fatal("cvs_merge_file: lseek fds[2]: %s", strerror(errno)); 212 if (lseek(fds[3], 0, SEEK_SET) < 0) 213 fatal("cvs_merge_file: lseek fds[3]: %s", strerror(errno)); 214 if (lseek(fds[4], 0, SEEK_SET) < 0) 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 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 = overlap = NULL; 299 300 increase(); 301 302 /* fds[0] and fds[1] are closed in readin() */ 303 m = readin(fds[0], &d13); 304 n = readin(fds[1], &d23); 305 306 for (i = 0; i <= 2; i++) { 307 if ((fp[i] = fdopen(fds[i + 2], "r")) == NULL) { 308 cvs_log(LP_ERR, "%s", argv[i + 2]); 309 return (-1); 310 } 311 } 312 313 return (merge(m, n)); 314 } 315 316 int 317 ed_patch_lines(struct rcs_lines *dlines, struct rcs_lines *plines) 318 { 319 char op, *ep; 320 struct rcs_line *sort, *lp, *dlp, *ndlp, *insert_after; 321 int start, end, i, lineno; 322 u_char tmp; 323 324 dlp = TAILQ_FIRST(&(dlines->l_lines)); 325 lp = TAILQ_FIRST(&(plines->l_lines)); 326 327 end = 0; 328 for (lp = TAILQ_NEXT(lp, l_list); lp != NULL; 329 lp = TAILQ_NEXT(lp, l_list)) { 330 /* Skip blank lines */ 331 if (lp->l_len < 2) 332 continue; 333 334 /* NUL-terminate line buffer for strtol() safety. */ 335 tmp = lp->l_line[lp->l_len - 1]; 336 lp->l_line[lp->l_len - 1] = '\0'; 337 338 op = lp->l_line[strlen(lp->l_line) - 1]; 339 start = (int)strtol(lp->l_line, &ep, 10); 340 341 /* Restore the last byte of the buffer */ 342 lp->l_line[lp->l_len - 1] = tmp; 343 344 if (op == 'a') { 345 if (start > dlines->l_nblines || 346 start < 0 || *ep != 'a') 347 fatal("ed_patch_lines %d", start); 348 } else if (op == 'c') { 349 if (start > dlines->l_nblines || 350 start < 0 || (*ep != ',' && *ep != 'c')) 351 fatal("ed_patch_lines"); 352 353 if (*ep == ',') { 354 ep++; 355 end = (int)strtol(ep, &ep, 10); 356 if (end < 0 || *ep != 'c') 357 fatal("ed_patch_lines"); 358 } else { 359 end = start; 360 } 361 } else { 362 fatal("invalid op %c found while merging", op); 363 } 364 365 366 for (;;) { 367 if (dlp == NULL) 368 break; 369 if (dlp->l_lineno == start) 370 break; 371 if (dlp->l_lineno > start) { 372 dlp = TAILQ_PREV(dlp, tqh, l_list); 373 } else if (dlp->l_lineno < start) { 374 ndlp = TAILQ_NEXT(dlp, l_list); 375 if (ndlp->l_lineno > start) 376 break; 377 dlp = ndlp; 378 } 379 } 380 381 if (dlp == NULL) 382 fatal("ed_patch_lines"); 383 384 385 if (op == 'c') { 386 insert_after = TAILQ_PREV(dlp, tqh, l_list); 387 for (i = 0; i <= (end - start); i++) { 388 ndlp = TAILQ_NEXT(dlp, l_list); 389 TAILQ_REMOVE(&(dlines->l_lines), dlp, l_list); 390 dlp = ndlp; 391 } 392 dlp = insert_after; 393 } 394 395 if (op == 'a' || op == 'c') { 396 for (;;) { 397 ndlp = lp; 398 lp = TAILQ_NEXT(lp, l_list); 399 if (lp == NULL) 400 fatal("ed_patch_lines"); 401 402 if (lp->l_len == 2 && 403 lp->l_line[0] == '.' && 404 lp->l_line[1] == '\n') 405 break; 406 407 TAILQ_REMOVE(&(plines->l_lines), lp, l_list); 408 TAILQ_INSERT_AFTER(&(dlines->l_lines), dlp, 409 lp, l_list); 410 dlp = lp; 411 412 lp->l_lineno = start; 413 lp = ndlp; 414 } 415 } 416 417 /* 418 * always resort lines as the markers might be put at the 419 * same line as we first started editing. 420 */ 421 lineno = 0; 422 TAILQ_FOREACH(sort, &(dlines->l_lines), l_list) 423 sort->l_lineno = lineno++; 424 dlines->l_nblines = lineno - 1; 425 } 426 427 return (0); 428 } 429 430 /* 431 * Pick up the line numbers of all changes from one change file. 432 * (This puts the numbers in a vector, which is not strictly necessary, 433 * since the vector is processed in one sequential pass. 434 * The vector could be optimized out of existence) 435 */ 436 static size_t 437 readin(int fd, struct diff **dd) 438 { 439 int a, b, c, d; 440 char kind, *p; 441 size_t i; 442 443 fp[0] = fdopen(fd, "r"); 444 if (fp[0] == NULL) 445 fatal("readin: fdopen: %s", strerror(errno)); 446 447 for (i = 0; (p = getchange(fp[0])); i++) { 448 if (i >= szchanges - 1) 449 increase(); 450 a = b = number(&p); 451 if (*p == ',') { 452 p++; 453 b = number(&p); 454 } 455 kind = *p++; 456 c = d = number(&p); 457 if (*p==',') { 458 p++; 459 d = number(&p); 460 } 461 if (kind == 'a') 462 a++; 463 if (kind == 'd') 464 c++; 465 b++; 466 d++; 467 (*dd)[i].old.from = a; 468 (*dd)[i].old.to = b; 469 (*dd)[i].new.from = c; 470 (*dd)[i].new.to = d; 471 } 472 473 if (i) { 474 (*dd)[i].old.from = (*dd)[i-1].old.to; 475 (*dd)[i].new.from = (*dd)[i-1].new.to; 476 } 477 478 (void)fclose(fp[0]); 479 480 return (i); 481 } 482 483 static int 484 number(char **lc) 485 { 486 int nn; 487 488 nn = 0; 489 while (isdigit((unsigned char)(**lc))) 490 nn = nn*10 + *(*lc)++ - '0'; 491 492 return (nn); 493 } 494 495 static char * 496 getchange(FILE *b) 497 { 498 char *line; 499 500 while ((line = get_line(b, NULL))) { 501 if (isdigit((unsigned char)line[0])) 502 return (line); 503 } 504 505 return (NULL); 506 } 507 508 static char * 509 get_line(FILE *b, size_t *n) 510 { 511 char *cp; 512 size_t len; 513 static char *buf; 514 static size_t bufsize; 515 516 if ((cp = fgetln(b, &len)) == NULL) 517 return (NULL); 518 519 if (cp[len - 1] != '\n') 520 len++; 521 if (len + 1 > bufsize) { 522 do { 523 bufsize += 1024; 524 } while (len + 1 > bufsize); 525 buf = xreallocarray(buf, 1, bufsize); 526 } 527 memcpy(buf, cp, len - 1); 528 buf[len - 1] = '\n'; 529 buf[len] = '\0'; 530 if (n != NULL) 531 *n = len; 532 533 return (buf); 534 } 535 536 static int 537 merge(size_t m1, size_t m2) 538 { 539 struct diff *d1, *d2, *d3; 540 int dpl, j, t1, t2; 541 542 d1 = d13; 543 d2 = d23; 544 j = 0; 545 while ((t1 = (d1 < d13 + m1)) | (t2 = (d2 < d23 + m2))) { 546 if (debug) { 547 printf("%d,%d=%d,%d %d,%d=%d,%d\n", 548 d1->old.from, d1->old.to, 549 d1->new.from, d1->new.to, 550 d2->old.from, d2->old.to, 551 d2->new.from, d2->new.to); 552 } 553 554 /* first file is different from others */ 555 if (!t2 || (t1 && d1->new.to < d2->new.from)) { 556 /* stuff peculiar to 1st file */ 557 if (eflag==0) { 558 separate("1"); 559 change(1, &d1->old, 0); 560 keep(2, &d1->new); 561 change(3, &d1->new, 0); 562 } 563 d1++; 564 continue; 565 } 566 567 /* second file is different from others */ 568 if (!t1 || (t2 && d2->new.to < d1->new.from)) { 569 if (eflag==0) { 570 separate("2"); 571 keep(1, &d2->new); 572 change(2, &d2->old, 0); 573 change(3, &d2->new, 0); 574 } 575 d2++; 576 continue; 577 } 578 579 /* 580 * Merge overlapping changes in first file 581 * this happens after extension (see below). 582 */ 583 if (d1 + 1 < d13 + m1 && d1->new.to >= d1[1].new.from) { 584 d1[1].old.from = d1->old.from; 585 d1[1].new.from = d1->new.from; 586 d1++; 587 continue; 588 } 589 590 /* merge overlapping changes in second */ 591 if (d2 + 1 < d23 + m2 && d2->new.to >= d2[1].new.from) { 592 d2[1].old.from = d2->old.from; 593 d2[1].new.from = d2->new.from; 594 d2++; 595 continue; 596 } 597 /* stuff peculiar to third file or different in all */ 598 if (d1->new.from == d2->new.from && d1->new.to == d2->new.to) { 599 dpl = duplicate(&d1->old,&d2->old); 600 if (dpl == -1) 601 return (-1); 602 603 /* 604 * dpl = 0 means all files differ 605 * dpl = 1 means files 1 and 2 identical 606 */ 607 if (eflag==0) { 608 separate(dpl ? "3" : ""); 609 change(1, &d1->old, dpl); 610 change(2, &d2->old, 0); 611 d3 = d1->old.to > d1->old.from ? d1 : d2; 612 change(3, &d3->new, 0); 613 } else 614 j = edit(d1, dpl, j); 615 d1++; 616 d2++; 617 continue; 618 } 619 620 /* 621 * Overlapping changes from file 1 and 2; extend changes 622 * appropriately to make them coincide. 623 */ 624 if (d1->new.from < d2->new.from) { 625 d2->old.from -= d2->new.from-d1->new.from; 626 d2->new.from = d1->new.from; 627 } else if (d2->new.from < d1->new.from) { 628 d1->old.from -= d1->new.from-d2->new.from; 629 d1->new.from = d2->new.from; 630 } 631 if (d1->new.to > d2->new.to) { 632 d2->old.to += d1->new.to - d2->new.to; 633 d2->new.to = d1->new.to; 634 } else if (d2->new.to > d1->new.to) { 635 d1->old.to += d2->new.to - d1->new.to; 636 d1->new.to = d2->new.to; 637 } 638 } 639 640 return (edscript(j)); 641 } 642 643 static void 644 separate(const char *s) 645 { 646 diff_output("====%s\n", s); 647 } 648 649 /* 650 * The range of lines rold.from thru rold.to in file i is to be changed. 651 * It is to be printed only if it does not duplicate something to be 652 * printed later. 653 */ 654 static void 655 change(int i, struct range *rold, int fdup) 656 { 657 diff_output("%d:", i); 658 last[i] = rold->to; 659 prange(rold); 660 if (fdup || debug) 661 return; 662 i--; 663 (void)skip(i, rold->from, NULL); 664 (void)skip(i, rold->to, " "); 665 } 666 667 /* 668 * print the range of line numbers, rold.from thru rold.to, as n1,n2 or n1 669 */ 670 static void 671 prange(struct range *rold) 672 { 673 if (rold->to <= rold->from) 674 diff_output("%da\n", rold->from - 1); 675 else { 676 diff_output("%d", rold->from); 677 if (rold->to > rold->from+1) 678 diff_output(",%d", rold->to - 1); 679 diff_output("c\n"); 680 } 681 } 682 683 /* 684 * No difference was reported by diff between file 1 (or 2) and file 3, 685 * and an artificial dummy difference (trange) must be ginned up to 686 * correspond to the change reported in the other file. 687 */ 688 static void 689 keep(int i, struct range *rnew) 690 { 691 int delta; 692 struct range trange; 693 694 delta = last[3] - last[i]; 695 trange.from = rnew->from - delta; 696 trange.to = rnew->to - delta; 697 change(i, &trange, 1); 698 } 699 700 /* 701 * skip to just before line number from in file "i". If "pr" is non-NULL, 702 * print all skipped stuff with string pr as a prefix. 703 */ 704 static int 705 skip(int i, int from, char *pr) 706 { 707 size_t j, n; 708 char *line; 709 710 for (n = 0; cline[i] < from - 1; n += j) { 711 if ((line = get_line(fp[i], &j)) == NULL) 712 return (-1); 713 if (pr != NULL) 714 diff_output("%s%s", pr, line); 715 cline[i]++; 716 } 717 return ((int) n); 718 } 719 720 /* 721 * Return 1 or 0 according as the old range (in file 1) contains exactly 722 * the same data as the new range (in file 2). 723 */ 724 static int 725 duplicate(struct range *r1, struct range *r2) 726 { 727 int c,d; 728 int nchar; 729 int nline; 730 731 if (r1->to-r1->from != r2->to-r2->from) 732 return (0); 733 (void)skip(0, r1->from, NULL); 734 (void)skip(1, r2->from, NULL); 735 nchar = 0; 736 for (nline=0; nline < r1->to - r1->from; nline++) { 737 do { 738 c = getc(fp[0]); 739 d = getc(fp[1]); 740 if (c == -1 || d== -1) 741 return (-1); 742 nchar++; 743 if (c != d) { 744 repos(nchar); 745 return (0); 746 } 747 } while (c != '\n'); 748 } 749 repos(nchar); 750 return (1); 751 } 752 753 static void 754 repos(int nchar) 755 { 756 int i; 757 758 for (i = 0; i < 2; i++) 759 (void)fseek(fp[i], (long)-nchar, SEEK_CUR); 760 } 761 762 /* 763 * collect an editing script for later regurgitation 764 */ 765 static int 766 edit(struct diff *diff, int fdup, int j) 767 { 768 if (((fdup + 1) & eflag) == 0) 769 return (j); 770 j++; 771 overlap[j] = !fdup; 772 if (!fdup) 773 overlapcnt++; 774 de[j].old.from = diff->old.from; 775 de[j].old.to = diff->old.to; 776 de[j].new.from = de[j-1].new.to + skip(2, diff->new.from, NULL); 777 de[j].new.to = de[j].new.from + skip(2, diff->new.to, NULL); 778 return (j); 779 } 780 781 /* regurgitate */ 782 static int 783 edscript(int n) 784 { 785 int j, k; 786 char block[BUFSIZ+1]; 787 788 for (n = n; n > 0; n--) { 789 if (!oflag || !overlap[n]) 790 prange(&de[n].old); 791 else 792 diff_output("%da\n=======\n", de[n].old.to -1); 793 (void)fseek(fp[2], (long)de[n].new.from, SEEK_SET); 794 for (k = de[n].new.to-de[n].new.from; k > 0; k-= j) { 795 j = k > BUFSIZ ? BUFSIZ : k; 796 if (fread(block, 1, j, fp[2]) != j) 797 return (-1); 798 block[j] = '\0'; 799 diff_output("%s", block); 800 } 801 802 if (!oflag || !overlap[n]) 803 diff_output(".\n"); 804 else { 805 diff_output("%s\n.\n", f3mark); 806 diff_output("%da\n%s\n.\n", de[n].old.from - 1, f1mark); 807 } 808 } 809 810 return (overlapcnt); 811 } 812 813 static void 814 increase(void) 815 { 816 size_t newsz, incr; 817 818 /* are the memset(3) calls needed? */ 819 newsz = szchanges == 0 ? 64 : 2 * szchanges; 820 incr = newsz - szchanges; 821 822 d13 = xreallocarray(d13, newsz, sizeof(*d13)); 823 memset(d13 + szchanges, 0, incr * sizeof(*d13)); 824 d23 = xreallocarray(d23, newsz, sizeof(*d23)); 825 memset(d23 + szchanges, 0, incr * sizeof(*d23)); 826 de = xreallocarray(de, newsz, sizeof(*de)); 827 memset(de + szchanges, 0, incr * sizeof(*de)); 828 overlap = xreallocarray(overlap, newsz, sizeof(*overlap)); 829 memset(overlap + szchanges, 0, incr * sizeof(*overlap)); 830 szchanges = newsz; 831 } 832