source: MondoRescue/branches/2.2.5/mindi-busybox/editors/diff.c@ 1765

Last change on this file since 1765 was 1765, checked in by Bruno Cornec, 16 years ago

Update to busybox 1.7.2
  • Property svn:eol-style set to native
File size: 30.1 KB
Line 
1/* vi: set sw=4 ts=4: */
2/*
3 * Mini diff implementation for busybox, adapted from OpenBSD diff.
4 *
5 * Copyright (C) 2006 by Robert Sullivan <cogito.ergo.cogito@hotmail.com>
6 * Copyright (c) 2003 Todd C. Miller <Todd.Miller@courtesan.com>
7 *
8 * Sponsored in part by the Defense Advanced Research Projects
9 * Agency (DARPA) and Air Force Research Laboratory, Air Force
10 * Materiel Command, USAF, under agreement number F39502-99-1-0512.
11 *
12 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
13 */
14
15#include "libbb.h"
16
17#define FSIZE_MAX 32768
18
19/*
20 * Output flags
21 */
22#define D_HEADER 1 /* Print a header/footer between files */
23#define D_EMPTY1 2 /* Treat first file as empty (/dev/null) */
24#define D_EMPTY2 4 /* Treat second file as empty (/dev/null) */
25
26/*
27 * Status values for print_status() and diffreg() return values
28 * Guide:
29 * D_SAME - files are the same
30 * D_DIFFER - files differ
31 * D_BINARY - binary files differ
32 * D_COMMON - subdirectory common to both dirs
33 * D_ONLY - file only exists in one dir
34 * D_MISMATCH1 - path1 a dir, path2 a file
35 * D_MISMATCH2 - path1 a file, path2 a dir
36 * D_ERROR - error occurred
37 * D_SKIPPED1 - skipped path1 as it is a special file
38 * D_SKIPPED2 - skipped path2 as it is a special file
39 */
40
41#define D_SAME 0
42#define D_DIFFER (1<<0)
43#define D_BINARY (1<<1)
44#define D_COMMON (1<<2)
45#define D_ONLY (1<<3)
46#define D_MISMATCH1 (1<<4)
47#define D_MISMATCH2 (1<<5)
48#define D_ERROR (1<<6)
49#define D_SKIPPED1 (1<<7)
50#define D_SKIPPED2 (1<<8)
51
52/* Command line options */
53#define FLAG_a (1<<0)
54#define FLAG_b (1<<1)
55#define FLAG_d (1<<2)
56#define FLAG_i (1<<3)
57#define FLAG_L (1<<4)
58#define FLAG_N (1<<5)
59#define FLAG_q (1<<6)
60#define FLAG_r (1<<7)
61#define FLAG_s (1<<8)
62#define FLAG_S (1<<9)
63#define FLAG_t (1<<10)
64#define FLAG_T (1<<11)
65#define FLAG_U (1<<12)
66#define FLAG_w (1<<13)
67
68#define g_read_buf bb_common_bufsiz1
69
70struct cand {
71 int x;
72 int y;
73 int pred;
74};
75
76struct line {
77 int serial;
78 int value;
79};
80
81/*
82 * The following struct is used to record change information
83 * doing a "context" or "unified" diff. (see routine "change" to
84 * understand the highly mnemonic field names)
85 */
86struct context_vec {
87 int a; /* start line in old file */
88 int b; /* end line in old file */
89 int c; /* start line in new file */
90 int d; /* end line in new file */
91};
92
93struct globals {
94 USE_FEATURE_DIFF_DIR(char **dl;)
95 USE_FEATURE_DIFF_DIR(int dl_count;)
96 /* This is the default number of lines of context. */
97 int context;
98 size_t max_context;
99 int status;
100 char *start;
101 const char *label1;
102 const char *label2;
103 struct line *file[2];
104 int *J; /* will be overlaid on class */
105 int *class; /* will be overlaid on file[0] */
106 int *klist; /* will be overlaid on file[0] after class */
107 int *member; /* will be overlaid on file[1] */
108 int clen;
109 int len[2];
110 int pref, suff; /* length of prefix and suffix */
111 int slen[2];
112 bool anychange;
113 long *ixnew; /* will be overlaid on file[1] */
114 long *ixold; /* will be overlaid on klist */
115 struct cand *clist; /* merely a free storage pot for candidates */
116 int clistlen; /* the length of clist */
117 struct line *sfile[2]; /* shortened by pruning common prefix/suffix */
118 struct context_vec *context_vec_start;
119 struct context_vec *context_vec_end;
120 struct context_vec *context_vec_ptr;
121 struct stat stb1, stb2;
122};
123#define G (*ptr_to_globals)
124#define dl (G.dl )
125#define dl_count (G.dl_count )
126#define context (G.context )
127#define max_context (G.max_context )
128#define status (G.status )
129#define start (G.start )
130#define label1 (G.label1 )
131#define label2 (G.label2 )
132#define file (G.file )
133#define J (G.J )
134#define class (G.class )
135#define klist (G.klist )
136#define member (G.member )
137#define clen (G.clen )
138#define len (G.len )
139#define pref (G.pref )
140#define suff (G.suff )
141#define slen (G.slen )
142#define anychange (G.anychange )
143#define ixnew (G.ixnew )
144#define ixold (G.ixold )
145#define clist (G.clist )
146#define clistlen (G.clistlen )
147#define sfile (G.sfile )
148#define context_vec_start (G.context_vec_start )
149#define context_vec_end (G.context_vec_end )
150#define context_vec_ptr (G.context_vec_ptr )
151#define stb1 (G.stb1 )
152#define stb2 (G.stb2 )
153#define INIT_G() do { \
154 PTR_TO_GLOBALS = xzalloc(sizeof(G)); \
155 context = 3; \
156 max_context = 64; \
157} while (0)
158
159
160static void print_only(const char *path, size_t dirlen, const char *entry)
161{
162 if (dirlen > 1)
163 dirlen--;
164 printf("Only in %.*s: %s\n", (int) dirlen, path, entry);
165}
166
167static void print_status(int val, char *path1, char *path2, char *entry)
168{
169 const char *const _entry = entry ? entry : "";
170 char * const _path1 = entry ? concat_path_file(path1, _entry) : path1;
171 char * const _path2 = entry ? concat_path_file(path2, _entry) : path2;
172
173 switch (val) {
174 case D_ONLY:
175 print_only(path1, strlen(path1), entry);
176 break;
177 case D_COMMON:
178 printf("Common subdirectories: %s and %s\n", _path1, _path2);
179 break;
180 case D_BINARY:
181 printf("Binary files %s and %s differ\n", _path1, _path2);
182 break;
183 case D_DIFFER:
184 if (option_mask32 & FLAG_q)
185 printf("Files %s and %s differ\n", _path1, _path2);
186 break;
187 case D_SAME:
188 if (option_mask32 & FLAG_s)
189 printf("Files %s and %s are identical\n", _path1, _path2);
190 break;
191 case D_MISMATCH1:
192 printf("File %s is a %s while file %s is a %s\n",
193 _path1, "directory", _path2, "regular file");
194 break;
195 case D_MISMATCH2:
196 printf("File %s is a %s while file %s is a %s\n",
197 _path1, "regular file", _path2, "directory");
198 break;
199 case D_SKIPPED1:
200 printf("File %s is not a regular file or directory and was skipped\n",
201 _path1);
202 break;
203 case D_SKIPPED2:
204 printf("File %s is not a regular file or directory and was skipped\n",
205 _path2);
206 break;
207 }
208 if (entry) {
209 free(_path1);
210 free(_path2);
211 }
212}
213static ALWAYS_INLINE int fiddle_sum(int sum, int t)
214{
215 return sum * 127 + t;
216}
217/*
218 * Hash function taken from Robert Sedgewick, Algorithms in C, 3d ed., p 578.
219 */
220static int readhash(FILE *fp)
221{
222 int i, t, space;
223 int sum;
224
225 sum = 1;
226 space = 0;
227 if (!(option_mask32 & (FLAG_b | FLAG_w))) {
228 for (i = 0; (t = getc(fp)) != '\n'; i++) {
229 if (t == EOF) {
230 if (i == 0)
231 return 0;
232 break;
233 }
234 sum = fiddle_sum(sum, t);
235 }
236 } else {
237 for (i = 0;;) {
238 switch (t = getc(fp)) {
239 case '\t':
240 case '\r':
241 case '\v':
242 case '\f':
243 case ' ':
244 space++;
245 continue;
246 default:
247 if (space && !(option_mask32 & FLAG_w)) {
248 i++;
249 space = 0;
250 }
251 sum = fiddle_sum(sum, t);
252 i++;
253 continue;
254 case EOF:
255 if (i == 0)
256 return 0;
257 /* FALLTHROUGH */
258 case '\n':
259 break;
260 }
261 break;
262 }
263 }
264 /*
265 * There is a remote possibility that we end up with a zero sum.
266 * Zero is used as an EOF marker, so return 1 instead.
267 */
268 return (sum == 0 ? 1 : sum);
269}
270
271
272/*
273 * Check to see if the given files differ.
274 * Returns 0 if they are the same, 1 if different, and -1 on error.
275 */
276static int files_differ(FILE *f1, FILE *f2, int flags)
277{
278 size_t i, j;
279
280 if ((flags & (D_EMPTY1 | D_EMPTY2)) || stb1.st_size != stb2.st_size
281 || (stb1.st_mode & S_IFMT) != (stb2.st_mode & S_IFMT)
282 ) {
283 return 1;
284 }
285 while (1) {
286 i = fread(g_read_buf, 1, COMMON_BUFSIZE/2, f1);
287 j = fread(g_read_buf + COMMON_BUFSIZE/2, 1, COMMON_BUFSIZE/2, f2);
288 if (i != j)
289 return 1;
290 if (i == 0)
291 return (ferror(f1) || ferror(f2));
292 if (memcmp(g_read_buf,
293 g_read_buf + COMMON_BUFSIZE/2, i) != 0)
294 return 1;
295 }
296}
297
298
299static void prepare(int i, FILE *fp /*, off_t filesize*/)
300{
301 struct line *p;
302 int h;
303 size_t j, sz;
304
305 rewind(fp);
306
307 /*sz = (filesize <= FSIZE_MAX ? filesize : FSIZE_MAX) / 25;*/
308 /*if (sz < 100)*/
309 sz = 100;
310
311 p = xmalloc((sz + 3) * sizeof(p[0]));
312 j = 0;
313 while ((h = readhash(fp))) {
314 if (j == sz) {
315 sz = sz * 3 / 2;
316 p = xrealloc(p, (sz + 3) * sizeof(p[0]));
317 }
318 p[++j].value = h;
319 }
320 len[i] = j;
321 file[i] = p;
322}
323
324
325static void prune(void)
326{
327 int i, j;
328
329 for (pref = 0; pref < len[0] && pref < len[1] &&
330 file[0][pref + 1].value == file[1][pref + 1].value; pref++)
331 continue;
332 for (suff = 0; suff < len[0] - pref && suff < len[1] - pref &&
333 file[0][len[0] - suff].value == file[1][len[1] - suff].value;
334 suff++)
335 continue;
336 for (j = 0; j < 2; j++) {
337 sfile[j] = file[j] + pref;
338 slen[j] = len[j] - pref - suff;
339 for (i = 0; i <= slen[j]; i++)
340 sfile[j][i].serial = i;
341 }
342}
343
344
345static void equiv(struct line *a, int n, struct line *b, int m, int *c)
346{
347 int i, j;
348
349 i = j = 1;
350 while (i <= n && j <= m) {
351 if (a[i].value < b[j].value)
352 a[i++].value = 0;
353 else if (a[i].value == b[j].value)
354 a[i++].value = j;
355 else
356 j++;
357 }
358 while (i <= n)
359 a[i++].value = 0;
360 b[m + 1].value = 0;
361 j = 0;
362 while (++j <= m) {
363 c[j] = -b[j].serial;
364 while (b[j + 1].value == b[j].value) {
365 j++;
366 c[j] = b[j].serial;
367 }
368 }
369 c[j] = -1;
370}
371
372
373static int isqrt(int n)
374{
375 int y, x;
376
377 if (n == 0)
378 return 0;
379 x = 1;
380 do {
381 y = x;
382 x = n / x;
383 x += y;
384 x /= 2;
385 } while ((x - y) > 1 || (x - y) < -1);
386
387 return x;
388}
389
390
391static int newcand(int x, int y, int pred)
392{
393 struct cand *q;
394
395 if (clen == clistlen) {
396 clistlen = clistlen * 11 / 10;
397 clist = xrealloc(clist, clistlen * sizeof(struct cand));
398 }
399 q = clist + clen;
400 q->x = x;
401 q->y = y;
402 q->pred = pred;
403 return clen++;
404}
405
406
407static int search(int *c, int k, int y)
408{
409 int i, j, l, t;
410
411 if (clist[c[k]].y < y) /* quick look for typical case */
412 return k + 1;
413 i = 0;
414 j = k + 1;
415 while (1) {
416 l = i + j;
417 if ((l >>= 1) <= i)
418 break;
419 t = clist[c[l]].y;
420 if (t > y)
421 j = l;
422 else if (t < y)
423 i = l;
424 else
425 return l;
426 }
427 return l + 1;
428}
429
430
431static int stone(int *a, int n, int *b, int *c)
432{
433 int i, k, y, j, l;
434 int oldc, tc, oldl;
435 unsigned int numtries;
436
437#if ENABLE_FEATURE_DIFF_MINIMAL
438 const unsigned int bound =
439 (option_mask32 & FLAG_d) ? UINT_MAX : MAX(256, isqrt(n));
440#else
441 const unsigned int bound = MAX(256, isqrt(n));
442#endif
443 k = 0;
444 c[0] = newcand(0, 0, 0);
445 for (i = 1; i <= n; i++) {
446 j = a[i];
447 if (j == 0)
448 continue;
449 y = -b[j];
450 oldl = 0;
451 oldc = c[0];
452 numtries = 0;
453 do {
454 if (y <= clist[oldc].y)
455 continue;
456 l = search(c, k, y);
457 if (l != oldl + 1)
458 oldc = c[l - 1];
459 if (l <= k) {
460 if (clist[c[l]].y <= y)
461 continue;
462 tc = c[l];
463 c[l] = newcand(i, y, oldc);
464 oldc = tc;
465 oldl = l;
466 numtries++;
467 } else {
468 c[l] = newcand(i, y, oldc);
469 k++;
470 break;
471 }
472 } while ((y = b[++j]) > 0 && numtries < bound);
473 }
474 return k;
475}
476
477
478static void unravel(int p)
479{
480 struct cand *q;
481 int i;
482
483 for (i = 0; i <= len[0]; i++)
484 J[i] = i <= pref ? i : i > len[0] - suff ? i + len[1] - len[0] : 0;
485 for (q = clist + p; q->y != 0; q = clist + q->pred)
486 J[q->x + pref] = q->y + pref;
487}
488
489
490static void unsort(struct line *f, int l, int *b)
491{
492 int *a, i;
493
494 a = xmalloc((l + 1) * sizeof(int));
495 for (i = 1; i <= l; i++)
496 a[f[i].serial] = f[i].value;
497 for (i = 1; i <= l; i++)
498 b[i] = a[i];
499 free(a);
500}
501
502
503static int skipline(FILE * f)
504{
505 int i, c;
506
507 for (i = 1; (c = getc(f)) != '\n' && c != EOF; i++)
508 continue;
509 return i;
510}
511
512
513/*
514 * Check does double duty:
515 * 1. ferret out any fortuitous correspondences due
516 * to confounding by hashing (which result in "jackpot")
517 * 2. collect random access indexes to the two files
518 */
519static void check(FILE * f1, FILE * f2)
520{
521 int i, j, jackpot, c, d;
522 long ctold, ctnew;
523
524 rewind(f1);
525 rewind(f2);
526 j = 1;
527 ixold[0] = ixnew[0] = 0;
528 jackpot = 0;
529 ctold = ctnew = 0;
530 for (i = 1; i <= len[0]; i++) {
531 if (J[i] == 0) {
532 ixold[i] = ctold += skipline(f1);
533 continue;
534 }
535 while (j < J[i]) {
536 ixnew[j] = ctnew += skipline(f2);
537 j++;
538 }
539 if ((option_mask32 & FLAG_b) || (option_mask32 & FLAG_w)
540 || (option_mask32 & FLAG_i)) {
541 while (1) {
542 c = getc(f1);
543 d = getc(f2);
544 /*
545 * GNU diff ignores a missing newline
546 * in one file if bflag || wflag.
547 */
548 if (((option_mask32 & FLAG_b) || (option_mask32 & FLAG_w)) &&
549 ((c == EOF && d == '\n') || (c == '\n' && d == EOF))) {
550 break;
551 }
552 ctold++;
553 ctnew++;
554 if ((option_mask32 & FLAG_b) && isspace(c) && isspace(d)) {
555 do {
556 if (c == '\n')
557 break;
558 ctold++;
559 } while (isspace(c = getc(f1)));
560 do {
561 if (d == '\n')
562 break;
563 ctnew++;
564 } while (isspace(d = getc(f2)));
565 } else if (option_mask32 & FLAG_w) {
566 while (isspace(c) && c != '\n') {
567 c = getc(f1);
568 ctold++;
569 }
570 while (isspace(d) && d != '\n') {
571 d = getc(f2);
572 ctnew++;
573 }
574 }
575 if (c != d) {
576 jackpot++;
577 J[i] = 0;
578 if (c != '\n' && c != EOF)
579 ctold += skipline(f1);
580 if (d != '\n' && c != EOF)
581 ctnew += skipline(f2);
582 break;
583 }
584 if (c == '\n' || c == EOF)
585 break;
586 }
587 } else {
588 while (1) {
589 ctold++;
590 ctnew++;
591 if ((c = getc(f1)) != (d = getc(f2))) {
592 J[i] = 0;
593 if (c != '\n' && c != EOF)
594 ctold += skipline(f1);
595 if (d != '\n' && c != EOF)
596 ctnew += skipline(f2);
597 break;
598 }
599 if (c == '\n' || c == EOF)
600 break;
601 }
602 }
603 ixold[i] = ctold;
604 ixnew[j] = ctnew;
605 j++;
606 }
607 for (; j <= len[1]; j++)
608 ixnew[j] = ctnew += skipline(f2);
609}
610
611
612/* shellsort CACM #201 */
613static void sort(struct line *a, int n)
614{
615 struct line *ai, *aim, w;
616 int j, m = 0, k;
617
618 if (n == 0)
619 return;
620 for (j = 1; j <= n; j *= 2)
621 m = 2 * j - 1;
622 for (m /= 2; m != 0; m /= 2) {
623 k = n - m;
624 for (j = 1; j <= k; j++) {
625 for (ai = &a[j]; ai > a; ai -= m) {
626 aim = &ai[m];
627 if (aim < ai)
628 break; /* wraparound */
629 if (aim->value > ai[0].value ||
630 (aim->value == ai[0].value && aim->serial > ai[0].serial))
631 break;
632 w.value = ai[0].value;
633 ai[0].value = aim->value;
634 aim->value = w.value;
635 w.serial = ai[0].serial;
636 ai[0].serial = aim->serial;
637 aim->serial = w.serial;
638 }
639 }
640 }
641}
642
643
644static void uni_range(int a, int b)
645{
646 if (a < b)
647 printf("%d,%d", a, b - a + 1);
648 else if (a == b)
649 printf("%d", b);
650 else
651 printf("%d,0", b);
652}
653
654
655static void fetch(long *f, int a, int b, FILE * lb, int ch)
656{
657 int i, j, c, lastc, col, nc;
658
659 if (a > b)
660 return;
661 for (i = a; i <= b; i++) {
662 fseek(lb, f[i - 1], SEEK_SET);
663 nc = f[i] - f[i - 1];
664 if (ch != '\0') {
665 putchar(ch);
666 if (option_mask32 & FLAG_T)
667 putchar('\t');
668 }
669 col = 0;
670 for (j = 0, lastc = '\0'; j < nc; j++, lastc = c) {
671 if ((c = getc(lb)) == EOF) {
672 printf("\n\\ No newline at end of file\n");
673 return;
674 }
675 if (c == '\t' && (option_mask32 & FLAG_t)) {
676 do {
677 putchar(' ');
678 } while (++col & 7);
679 } else {
680 putchar(c);
681 col++;
682 }
683 }
684 }
685}
686
687
688static int asciifile(FILE * f)
689{
690#if ENABLE_FEATURE_DIFF_BINARY
691 int i, cnt;
692#endif
693
694 if ((option_mask32 & FLAG_a) || f == NULL)
695 return 1;
696
697#if ENABLE_FEATURE_DIFF_BINARY
698 rewind(f);
699 cnt = fread(g_read_buf, 1, COMMON_BUFSIZE, f);
700 for (i = 0; i < cnt; i++) {
701 if (!isprint(g_read_buf[i])
702 && !isspace(g_read_buf[i])) {
703 return 0;
704 }
705 }
706#endif
707 return 1;
708}
709
710
711/* dump accumulated "unified" diff changes */
712static void dump_unified_vec(FILE * f1, FILE * f2)
713{
714 struct context_vec *cvp = context_vec_start;
715 int lowa, upb, lowc, upd;
716 int a, b, c, d;
717 char ch;
718
719 if (context_vec_start > context_vec_ptr)
720 return;
721
722 b = d = 0; /* gcc */
723 lowa = MAX(1, cvp->a - context);
724 upb = MIN(len[0], context_vec_ptr->b + context);
725 lowc = MAX(1, cvp->c - context);
726 upd = MIN(len[1], context_vec_ptr->d + context);
727
728 printf("@@ -");
729 uni_range(lowa, upb);
730 printf(" +");
731 uni_range(lowc, upd);
732 printf(" @@\n");
733
734 /*
735 * Output changes in "unified" diff format--the old and new lines
736 * are printed together.
737 */
738 for (; cvp <= context_vec_ptr; cvp++) {
739 a = cvp->a;
740 b = cvp->b;
741 c = cvp->c;
742 d = cvp->d;
743
744 /*
745 * c: both new and old changes
746 * d: only changes in the old file
747 * a: only changes in the new file
748 */
749 if (a <= b && c <= d)
750 ch = 'c';
751 else
752 ch = (a <= b) ? 'd' : 'a';
753#if 0
754 switch (ch) {
755 case 'c':
756 fetch(ixold, lowa, a - 1, f1, ' ');
757 fetch(ixold, a, b, f1, '-');
758 fetch(ixnew, c, d, f2, '+');
759 break;
760 case 'd':
761 fetch(ixold, lowa, a - 1, f1, ' ');
762 fetch(ixold, a, b, f1, '-');
763 break;
764 case 'a':
765 fetch(ixnew, lowc, c - 1, f2, ' ');
766 fetch(ixnew, c, d, f2, '+');
767 break;
768 }
769#else
770 if (ch == 'c' || ch == 'd') {
771 fetch(ixold, lowa, a - 1, f1, ' ');
772 fetch(ixold, a, b, f1, '-');
773 }
774 if (ch == 'a')
775 fetch(ixnew, lowc, c - 1, f2, ' ');
776 if (ch == 'c' || ch == 'a')
777 fetch(ixnew, c, d, f2, '+');
778#endif
779 lowa = b + 1;
780 lowc = d + 1;
781 }
782 fetch(ixnew, d + 1, upd, f2, ' ');
783
784 context_vec_ptr = context_vec_start - 1;
785}
786
787
788static void print_header(const char *file1, const char *file2)
789{
790 if (label1)
791 printf("--- %s\n", label1);
792 else
793 printf("--- %s\t%s", file1, ctime(&stb1.st_mtime));
794 if (label2)
795 printf("+++ %s\n", label2);
796 else
797 printf("+++ %s\t%s", file2, ctime(&stb2.st_mtime));
798}
799
800
801/*
802 * Indicate that there is a difference between lines a and b of the from file
803 * to get to lines c to d of the to file. If a is greater than b then there
804 * are no lines in the from file involved and this means that there were
805 * lines appended (beginning at b). If c is greater than d then there are
806 * lines missing from the to file.
807 */
808static void change(char *file1, FILE * f1, char *file2, FILE * f2, int a,
809 int b, int c, int d)
810{
811 if ((a > b && c > d) || (option_mask32 & FLAG_q)) {
812 anychange = 1;
813 return;
814 }
815
816 /*
817 * Allocate change records as needed.
818 */
819 if (context_vec_ptr == context_vec_end - 1) {
820 ptrdiff_t offset = context_vec_ptr - context_vec_start;
821
822 max_context <<= 1;
823 context_vec_start = xrealloc(context_vec_start,
824 max_context * sizeof(struct context_vec));
825 context_vec_end = context_vec_start + max_context;
826 context_vec_ptr = context_vec_start + offset;
827 }
828 if (anychange == 0) {
829 /*
830 * Print the context/unidiff header first time through.
831 */
832 print_header(file1, file2);
833 } else if (a > context_vec_ptr->b + (2 * context) + 1 &&
834 c > context_vec_ptr->d + (2 * context) + 1) {
835 /*
836 * If this change is more than 'context' lines from the
837 * previous change, dump the record and reset it.
838 */
839 dump_unified_vec(f1, f2);
840 }
841 context_vec_ptr++;
842 context_vec_ptr->a = a;
843 context_vec_ptr->b = b;
844 context_vec_ptr->c = c;
845 context_vec_ptr->d = d;
846 anychange = 1;
847}
848
849
850static void output(char *file1, FILE * f1, char *file2, FILE * f2)
851{
852 /* Note that j0 and j1 can't be used as they are defined in math.h.
853 * This also allows the rather amusing variable 'j00'... */
854 int m, i0, i1, j00, j01;
855
856 rewind(f1);
857 rewind(f2);
858 m = len[0];
859 J[0] = 0;
860 J[m + 1] = len[1] + 1;
861 for (i0 = 1; i0 <= m; i0 = i1 + 1) {
862 while (i0 <= m && J[i0] == J[i0 - 1] + 1)
863 i0++;
864 j00 = J[i0 - 1] + 1;
865 i1 = i0 - 1;
866 while (i1 < m && J[i1 + 1] == 0)
867 i1++;
868 j01 = J[i1 + 1] - 1;
869 J[i1] = j01;
870 change(file1, f1, file2, f2, i0, i1, j00, j01);
871 }
872 if (m == 0) {
873 change(file1, f1, file2, f2, 1, 0, 1, len[1]);
874 }
875 if (anychange != 0 && !(option_mask32 & FLAG_q)) {
876 dump_unified_vec(f1, f2);
877 }
878}
879
880/*
881 * The following code uses an algorithm due to Harold Stone,
882 * which finds a pair of longest identical subsequences in
883 * the two files.
884 *
885 * The major goal is to generate the match vector J.
886 * J[i] is the index of the line in file1 corresponding
887 * to line i file0. J[i] = 0 if there is no
888 * such line in file1.
889 *
890 * Lines are hashed so as to work in core. All potential
891 * matches are located by sorting the lines of each file
892 * on the hash (called ``value''). In particular, this
893 * collects the equivalence classes in file1 together.
894 * Subroutine equiv replaces the value of each line in
895 * file0 by the index of the first element of its
896 * matching equivalence in (the reordered) file1.
897 * To save space equiv squeezes file1 into a single
898 * array member in which the equivalence classes
899 * are simply concatenated, except that their first
900 * members are flagged by changing sign.
901 *
902 * Next the indices that point into member are unsorted into
903 * array class according to the original order of file0.
904 *
905 * The cleverness lies in routine stone. This marches
906 * through the lines of file0, developing a vector klist
907 * of "k-candidates". At step i a k-candidate is a matched
908 * pair of lines x,y (x in file0 y in file1) such that
909 * there is a common subsequence of length k
910 * between the first i lines of file0 and the first y
911 * lines of file1, but there is no such subsequence for
912 * any smaller y. x is the earliest possible mate to y
913 * that occurs in such a subsequence.
914 *
915 * Whenever any of the members of the equivalence class of
916 * lines in file1 matable to a line in file0 has serial number
917 * less than the y of some k-candidate, that k-candidate
918 * with the smallest such y is replaced. The new
919 * k-candidate is chained (via pred) to the current
920 * k-1 candidate so that the actual subsequence can
921 * be recovered. When a member has serial number greater
922 * that the y of all k-candidates, the klist is extended.
923 * At the end, the longest subsequence is pulled out
924 * and placed in the array J by unravel
925 *
926 * With J in hand, the matches there recorded are
927 * checked against reality to assure that no spurious
928 * matches have crept in due to hashing. If they have,
929 * they are broken, and "jackpot" is recorded--a harmless
930 * matter except that a true match for a spuriously
931 * mated line may now be unnecessarily reported as a change.
932 *
933 * Much of the complexity of the program comes simply
934 * from trying to minimize core utilization and
935 * maximize the range of doable problems by dynamically
936 * allocating what is needed and reusing what is not.
937 * The core requirements for problems larger than somewhat
938 * are (in words) 2*length(file0) + length(file1) +
939 * 3*(number of k-candidates installed), typically about
940 * 6n words for files of length n.
941 */
942static unsigned diffreg(char *ofile1, char *ofile2, int flags)
943{
944 char *file1 = ofile1;
945 char *file2 = ofile2;
946 FILE *f1 = stdin, *f2 = stdin;
947 unsigned rval;
948 int i;
949
950 anychange = 0;
951 context_vec_ptr = context_vec_start - 1;
952
953 if (S_ISDIR(stb1.st_mode) != S_ISDIR(stb2.st_mode))
954 return (S_ISDIR(stb1.st_mode) ? D_MISMATCH1 : D_MISMATCH2);
955
956 rval = D_SAME;
957
958 if (LONE_DASH(file1) && LONE_DASH(file2))
959 goto closem;
960
961 if (flags & D_EMPTY1)
962 f1 = xfopen(bb_dev_null, "r");
963 else if (NOT_LONE_DASH(file1))
964 f1 = xfopen(file1, "r");
965 if (flags & D_EMPTY2)
966 f2 = xfopen(bb_dev_null, "r");
967 else if (NOT_LONE_DASH(file2))
968 f2 = xfopen(file2, "r");
969
970/* We can't diff non-seekable stream - we use rewind(), fseek().
971 * This can be fixed (volunteers?).
972 * Meanwhile we should check it here by stat'ing input fds,
973 * but I am lazy and check that in main() instead.
974 * Check in main won't catch "diffing fifos buried in subdirectories"
975 * failure scenario - not very likely in real life... */
976
977 i = files_differ(f1, f2, flags);
978 if (i == 0)
979 goto closem;
980 else if (i != 1) { /* 1 == ok */
981 /* error */
982 status |= 2;
983 goto closem;
984 }
985
986 if (!asciifile(f1) || !asciifile(f2)) {
987 rval = D_BINARY;
988 status |= 1;
989 goto closem;
990 }
991
992 prepare(0, f1 /*, stb1.st_size*/);
993 prepare(1, f2 /*, stb2.st_size*/);
994 prune();
995 sort(sfile[0], slen[0]);
996 sort(sfile[1], slen[1]);
997
998 member = (int *) file[1];
999 equiv(sfile[0], slen[0], sfile[1], slen[1], member);
1000 member = xrealloc(member, (slen[1] + 2) * sizeof(int));
1001
1002 class = (int *) file[0];
1003 unsort(sfile[0], slen[0], class);
1004 class = xrealloc(class, (slen[0] + 2) * sizeof(int));
1005
1006 klist = xmalloc((slen[0] + 2) * sizeof(int));
1007 clen = 0;
1008 clistlen = 100;
1009 clist = xmalloc(clistlen * sizeof(struct cand));
1010 i = stone(class, slen[0], member, klist);
1011 free(member);
1012 free(class);
1013
1014 J = xrealloc(J, (len[0] + 2) * sizeof(int));
1015 unravel(klist[i]);
1016 free(clist);
1017 free(klist);
1018
1019 ixold = xrealloc(ixold, (len[0] + 2) * sizeof(long));
1020 ixnew = xrealloc(ixnew, (len[1] + 2) * sizeof(long));
1021 check(f1, f2);
1022 output(file1, f1, file2, f2);
1023
1024 closem:
1025 if (anychange) {
1026 status |= 1;
1027 if (rval == D_SAME)
1028 rval = D_DIFFER;
1029 }
1030 fclose_if_not_stdin(f1);
1031 fclose_if_not_stdin(f2);
1032 if (file1 != ofile1)
1033 free(file1);
1034 if (file2 != ofile2)
1035 free(file2);
1036 return rval;
1037}
1038
1039
1040#if ENABLE_FEATURE_DIFF_DIR
1041static void do_diff(char *dir1, char *path1, char *dir2, char *path2)
1042{
1043 int flags = D_HEADER;
1044 int val;
1045 char *fullpath1 = NULL; /* if -N */
1046 char *fullpath2 = NULL;
1047
1048 if (path1)
1049 fullpath1 = concat_path_file(dir1, path1);
1050 if (path2)
1051 fullpath2 = concat_path_file(dir2, path2);
1052
1053 if (!fullpath1 || stat(fullpath1, &stb1) != 0) {
1054 flags |= D_EMPTY1;
1055 memset(&stb1, 0, sizeof(stb1));
1056 if (path2) {
1057 free(fullpath1);
1058 fullpath1 = concat_path_file(dir1, path2);
1059 }
1060 }
1061 if (!fullpath2 || stat(fullpath2, &stb2) != 0) {
1062 flags |= D_EMPTY2;
1063 memset(&stb2, 0, sizeof(stb2));
1064 stb2.st_mode = stb1.st_mode;
1065 if (path1) {
1066 free(fullpath2);
1067 fullpath2 = concat_path_file(dir2, path1);
1068 }
1069 }
1070
1071 if (stb1.st_mode == 0)
1072 stb1.st_mode = stb2.st_mode;
1073
1074 if (S_ISDIR(stb1.st_mode) && S_ISDIR(stb2.st_mode)) {
1075 printf("Common subdirectories: %s and %s\n", fullpath1, fullpath2);
1076 goto ret;
1077 }
1078
1079 if (!S_ISREG(stb1.st_mode) && !S_ISDIR(stb1.st_mode))
1080 val = D_SKIPPED1;
1081 else if (!S_ISREG(stb2.st_mode) && !S_ISDIR(stb2.st_mode))
1082 val = D_SKIPPED2;
1083 else
1084 val = diffreg(fullpath1, fullpath2, flags);
1085
1086 print_status(val, fullpath1, fullpath2, NULL);
1087 ret:
1088 free(fullpath1);
1089 free(fullpath2);
1090}
1091#endif
1092
1093
1094#if ENABLE_FEATURE_DIFF_DIR
1095static int dir_strcmp(const void *p1, const void *p2)
1096{
1097 return strcmp(*(char *const *) p1, *(char *const *) p2);
1098}
1099
1100
1101/* This function adds a filename to dl, the directory listing. */
1102static int add_to_dirlist(const char *filename,
1103 struct stat ATTRIBUTE_UNUSED * sb, void *userdata,
1104 int depth ATTRIBUTE_UNUSED)
1105{
1106 /* +2: with space for eventual trailing NULL */
1107 dl = xrealloc(dl, (dl_count+2) * sizeof(dl[0]));
1108 dl[dl_count] = xstrdup(filename + (int)(ptrdiff_t)userdata);
1109 dl_count++;
1110 return TRUE;
1111}
1112
1113
1114/* This returns a sorted directory listing. */
1115static char **get_dir(char *path)
1116{
1117 dl_count = 0;
1118 dl = xzalloc(sizeof(dl[0]));
1119
1120 /* If -r has been set, then the recursive_action function will be
1121 * used. Unfortunately, this outputs the root directory along with
1122 * the recursed paths, so use void *userdata to specify the string
1123 * length of the root directory - '(void*)(strlen(path)+)'.
1124 * add_to_dirlist then removes root dir prefix. */
1125
1126 if (option_mask32 & FLAG_r) {
1127 recursive_action(path, ACTION_RECURSE|ACTION_FOLLOWLINKS,
1128 add_to_dirlist, NULL,
1129 (void*)(strlen(path)+1), 0);
1130 } else {
1131 DIR *dp;
1132 struct dirent *ep;
1133
1134 dp = warn_opendir(path);
1135 while ((ep = readdir(dp))) {
1136 if (!strcmp(ep->d_name, "..") || LONE_CHAR(ep->d_name, '.'))
1137 continue;
1138 add_to_dirlist(ep->d_name, NULL, (void*)(int)0, 0);
1139 }
1140 closedir(dp);
1141 }
1142
1143 /* Sort dl alphabetically. */
1144 qsort(dl, dl_count, sizeof(char *), dir_strcmp);
1145
1146 dl[dl_count] = NULL;
1147 return dl;
1148}
1149
1150
1151static void diffdir(char *p1, char *p2)
1152{
1153 char **dirlist1, **dirlist2;
1154 char *dp1, *dp2;
1155 int pos;
1156
1157 /* Check for trailing slashes. */
1158 dp1 = last_char_is(p1, '/');
1159 if (dp1 != NULL)
1160 *dp1 = '\0';
1161 dp2 = last_char_is(p2, '/');
1162 if (dp2 != NULL)
1163 *dp2 = '\0';
1164
1165 /* Get directory listings for p1 and p2. */
1166
1167 dirlist1 = get_dir(p1);
1168 dirlist2 = get_dir(p2);
1169
1170 /* If -S was set, find the starting point. */
1171 if (start) {
1172 while (*dirlist1 != NULL && strcmp(*dirlist1, start) < 0)
1173 dirlist1++;
1174 while (*dirlist2 != NULL && strcmp(*dirlist2, start) < 0)
1175 dirlist2++;
1176 if ((*dirlist1 == NULL) || (*dirlist2 == NULL))
1177 bb_error_msg(bb_msg_invalid_arg, "NULL", "-S");
1178 }
1179
1180 /* Now that both dirlist1 and dirlist2 contain sorted directory
1181 * listings, we can start to go through dirlist1. If both listings
1182 * contain the same file, then do a normal diff. Otherwise, behaviour
1183 * is determined by whether the -N flag is set. */
1184 while (*dirlist1 != NULL || *dirlist2 != NULL) {
1185 dp1 = *dirlist1;
1186 dp2 = *dirlist2;
1187 pos = dp1 == NULL ? 1 : dp2 == NULL ? -1 : strcmp(dp1, dp2);
1188 if (pos == 0) {
1189 do_diff(p1, dp1, p2, dp2);
1190 dirlist1++;
1191 dirlist2++;
1192 } else if (pos < 0) {
1193 if (option_mask32 & FLAG_N)
1194 do_diff(p1, dp1, p2, NULL);
1195 else
1196 print_only(p1, strlen(p1) + 1, dp1);
1197 dirlist1++;
1198 } else {
1199 if (option_mask32 & FLAG_N)
1200 do_diff(p1, NULL, p2, dp2);
1201 else
1202 print_only(p2, strlen(p2) + 1, dp2);
1203 dirlist2++;
1204 }
1205 }
1206}
1207#endif
1208
1209
1210int diff_main(int argc, char **argv);
1211int diff_main(int argc, char **argv)
1212{
1213 bool gotstdin = 0;
1214 char *U_opt;
1215 char *f1, *f2;
1216 llist_t *L_arg = NULL;
1217
1218 INIT_G();
1219
1220 /* exactly 2 params; collect multiple -L <label> */
1221 opt_complementary = "=2:L::";
1222 getopt32(argv, "abdiL:NqrsS:tTU:wu"
1223 "p" /* ignored (for compatibility) */,
1224 &L_arg, &start, &U_opt);
1225 /*argc -= optind;*/
1226 argv += optind;
1227 while (L_arg) {
1228 if (label1 && label2)
1229 bb_show_usage();
1230 if (!label1)
1231 label1 = L_arg->data;
1232 else { /* then label2 is NULL */
1233 label2 = label1;
1234 label1 = L_arg->data;
1235 }
1236 /* we leak L_arg here... */
1237 L_arg = L_arg->link;
1238 }
1239 if (option_mask32 & FLAG_U)
1240 context = xatoi_u(U_opt);
1241
1242 /*
1243 * Do sanity checks, fill in stb1 and stb2 and call the appropriate
1244 * driver routine. Both drivers use the contents of stb1 and stb2.
1245 */
1246
1247 f1 = argv[0];
1248 f2 = argv[1];
1249 if (LONE_DASH(f1)) {
1250 fstat(STDIN_FILENO, &stb1);
1251 gotstdin = 1;
1252 } else
1253 xstat(f1, &stb1);
1254 if (LONE_DASH(f2)) {
1255 fstat(STDIN_FILENO, &stb2);
1256 gotstdin = 1;
1257 } else
1258 xstat(f2, &stb2);
1259 if (gotstdin && (S_ISDIR(stb1.st_mode) || S_ISDIR(stb2.st_mode)))
1260 bb_error_msg_and_die("can't compare - to a directory");
1261 if (S_ISDIR(stb1.st_mode) && S_ISDIR(stb2.st_mode)) {
1262#if ENABLE_FEATURE_DIFF_DIR
1263 diffdir(f1, f2);
1264#else
1265 bb_error_msg_and_die("directory comparison not supported");
1266#endif
1267 } else {
1268 if (S_ISDIR(stb1.st_mode)) {
1269 f1 = concat_path_file(f1, f2);
1270 xstat(f1, &stb1);
1271 }
1272 if (S_ISDIR(stb2.st_mode)) {
1273 f2 = concat_path_file(f2, f1);
1274 xstat(f2, &stb2);
1275 }
1276/* XXX: FIXME: */
1277/* We can't diff e.g. stdin supplied by a pipe - we use rewind(), fseek().
1278 * This can be fixed (volunteers?) */
1279 if (!S_ISREG(stb1.st_mode) || !S_ISREG(stb2.st_mode))
1280 bb_error_msg_and_die("can't diff non-seekable stream");
1281 print_status(diffreg(f1, f2, 0), f1, f2, NULL);
1282 }
1283 return status;
1284}
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