Contents of /trunk/mkinitrd-magellan/busybox/editors/diff.c
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Sun May 30 11:32:42 2010 UTC (13 years, 11 months ago) by niro
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Sun May 30 11:32:42 2010 UTC (13 years, 11 months ago) by niro
File MIME type: text/plain
File size: 27171 byte(s)
-updated to busybox-1.16.1 and enabled blkid/uuid support in default config
1 | /* vi: set sw=4 ts=4: */ |
2 | /* |
3 | * Mini diff implementation for busybox, adapted from OpenBSD diff. |
4 | * |
5 | * Copyright (C) 2010 by Matheus Izvekov <mizvekov@gmail.com> |
6 | * Copyright (C) 2006 by Robert Sullivan <cogito.ergo.cogito@hotmail.com> |
7 | * Copyright (c) 2003 Todd C. Miller <Todd.Miller@courtesan.com> |
8 | * |
9 | * Sponsored in part by the Defense Advanced Research Projects |
10 | * Agency (DARPA) and Air Force Research Laboratory, Air Force |
11 | * Materiel Command, USAF, under agreement number F39502-99-1-0512. |
12 | * |
13 | * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. |
14 | */ |
15 | |
16 | /* |
17 | * The following code uses an algorithm due to Harold Stone, |
18 | * which finds a pair of longest identical subsequences in |
19 | * the two files. |
20 | * |
21 | * The major goal is to generate the match vector J. |
22 | * J[i] is the index of the line in file1 corresponding |
23 | * to line i in file0. J[i] = 0 if there is no |
24 | * such line in file1. |
25 | * |
26 | * Lines are hashed so as to work in core. All potential |
27 | * matches are located by sorting the lines of each file |
28 | * on the hash (called "value"). In particular, this |
29 | * collects the equivalence classes in file1 together. |
30 | * Subroutine equiv replaces the value of each line in |
31 | * file0 by the index of the first element of its |
32 | * matching equivalence in (the reordered) file1. |
33 | * To save space equiv squeezes file1 into a single |
34 | * array member in which the equivalence classes |
35 | * are simply concatenated, except that their first |
36 | * members are flagged by changing sign. |
37 | * |
38 | * Next the indices that point into member are unsorted into |
39 | * array class according to the original order of file0. |
40 | * |
41 | * The cleverness lies in routine stone. This marches |
42 | * through the lines of file0, developing a vector klist |
43 | * of "k-candidates". At step i a k-candidate is a matched |
44 | * pair of lines x,y (x in file0, y in file1) such that |
45 | * there is a common subsequence of length k |
46 | * between the first i lines of file0 and the first y |
47 | * lines of file1, but there is no such subsequence for |
48 | * any smaller y. x is the earliest possible mate to y |
49 | * that occurs in such a subsequence. |
50 | * |
51 | * Whenever any of the members of the equivalence class of |
52 | * lines in file1 matable to a line in file0 has serial number |
53 | * less than the y of some k-candidate, that k-candidate |
54 | * with the smallest such y is replaced. The new |
55 | * k-candidate is chained (via pred) to the current |
56 | * k-1 candidate so that the actual subsequence can |
57 | * be recovered. When a member has serial number greater |
58 | * that the y of all k-candidates, the klist is extended. |
59 | * At the end, the longest subsequence is pulled out |
60 | * and placed in the array J by unravel |
61 | * |
62 | * With J in hand, the matches there recorded are |
63 | * checked against reality to assure that no spurious |
64 | * matches have crept in due to hashing. If they have, |
65 | * they are broken, and "jackpot" is recorded--a harmless |
66 | * matter except that a true match for a spuriously |
67 | * mated line may now be unnecessarily reported as a change. |
68 | * |
69 | * Much of the complexity of the program comes simply |
70 | * from trying to minimize core utilization and |
71 | * maximize the range of doable problems by dynamically |
72 | * allocating what is needed and reusing what is not. |
73 | * The core requirements for problems larger than somewhat |
74 | * are (in words) 2*length(file0) + length(file1) + |
75 | * 3*(number of k-candidates installed), typically about |
76 | * 6n words for files of length n. |
77 | */ |
78 | |
79 | #include "libbb.h" |
80 | |
81 | #if 0 |
82 | //#define dbg_error_msg(...) bb_error_msg(__VA_ARGS__) |
83 | #else |
84 | #define dbg_error_msg(...) ((void)0) |
85 | #endif |
86 | |
87 | enum { /* print_status() and diffreg() return values */ |
88 | STATUS_SAME, /* files are the same */ |
89 | STATUS_DIFFER, /* files differ */ |
90 | STATUS_BINARY, /* binary files differ */ |
91 | }; |
92 | |
93 | enum { /* Commandline flags */ |
94 | FLAG_a, |
95 | FLAG_b, |
96 | FLAG_d, |
97 | FLAG_i, |
98 | FLAG_L, /* never used, handled by getopt32 */ |
99 | FLAG_N, |
100 | FLAG_q, |
101 | FLAG_r, |
102 | FLAG_s, |
103 | FLAG_S, /* never used, handled by getopt32 */ |
104 | FLAG_t, |
105 | FLAG_T, |
106 | FLAG_U, /* never used, handled by getopt32 */ |
107 | FLAG_w, |
108 | FLAG_u, /* ignored, this is the default */ |
109 | FLAG_p, /* not implemented */ |
110 | FLAG_B, |
111 | FLAG_E, /* not implemented */ |
112 | }; |
113 | #define FLAG(x) (1 << FLAG_##x) |
114 | |
115 | /* We cache file position to avoid excessive seeking */ |
116 | typedef struct FILE_and_pos_t { |
117 | FILE *ft_fp; |
118 | off_t ft_pos; |
119 | } FILE_and_pos_t; |
120 | |
121 | struct globals { |
122 | smallint exit_status; |
123 | int opt_U_context; |
124 | char *label[2]; |
125 | struct stat stb[2]; |
126 | }; |
127 | #define G (*ptr_to_globals) |
128 | #define exit_status (G.exit_status ) |
129 | #define opt_U_context (G.opt_U_context ) |
130 | #define label (G.label ) |
131 | #define stb (G.stb ) |
132 | #define INIT_G() do { \ |
133 | SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \ |
134 | opt_U_context = 3; \ |
135 | } while (0) |
136 | |
137 | typedef int token_t; |
138 | |
139 | enum { |
140 | /* Public */ |
141 | TOK_EMPTY = 1 << 9, /* Line fully processed, you can proceed to the next */ |
142 | TOK_EOF = 1 << 10, /* File ended */ |
143 | /* Private (Only to be used by read_token() */ |
144 | TOK_EOL = 1 << 11, /* we saw EOL (sticky) */ |
145 | TOK_SPACE = 1 << 12, /* used -b code, means we are skipping spaces */ |
146 | SHIFT_EOF = (sizeof(token_t)*8 - 8) - 1, |
147 | CHAR_MASK = 0x1ff, /* 8th bit is used to distinguish EOF from 0xff */ |
148 | }; |
149 | |
150 | /* Restores full EOF from one 8th bit: */ |
151 | //#define TOK2CHAR(t) (((t) << SHIFT_EOF) >> SHIFT_EOF) |
152 | /* We don't really need the above, we only need to have EOF != any_real_char: */ |
153 | #define TOK2CHAR(t) ((t) & CHAR_MASK) |
154 | |
155 | static void seek_ft(FILE_and_pos_t *ft, off_t pos) |
156 | { |
157 | if (ft->ft_pos != pos) { |
158 | ft->ft_pos = pos; |
159 | fseeko(ft->ft_fp, pos, SEEK_SET); |
160 | } |
161 | } |
162 | |
163 | /* Reads tokens from given fp, handling -b and -w flags |
164 | * The user must reset tok every line start |
165 | */ |
166 | static int read_token(FILE_and_pos_t *ft, token_t tok) |
167 | { |
168 | tok |= TOK_EMPTY; |
169 | while (!(tok & TOK_EOL)) { |
170 | bool is_space; |
171 | int t; |
172 | |
173 | t = fgetc(ft->ft_fp); |
174 | if (t != EOF) |
175 | ft->ft_pos++; |
176 | is_space = (t == EOF || isspace(t)); |
177 | |
178 | /* If t == EOF (-1), set both TOK_EOF and TOK_EOL */ |
179 | tok |= (t & (TOK_EOF + TOK_EOL)); |
180 | /* Only EOL? */ |
181 | if (t == '\n') |
182 | tok |= TOK_EOL; |
183 | |
184 | if (option_mask32 & FLAG(i)) /* Handcoded tolower() */ |
185 | t = (t >= 'A' && t <= 'Z') ? t - ('A' - 'a') : t; |
186 | |
187 | if ((option_mask32 & FLAG(w)) && is_space) |
188 | continue; |
189 | |
190 | /* Trim char value to low 9 bits */ |
191 | t &= CHAR_MASK; |
192 | |
193 | if (option_mask32 & FLAG(b)) { |
194 | /* Was prev char whitespace? */ |
195 | if (tok & TOK_SPACE) { /* yes */ |
196 | if (is_space) /* this one too, ignore it */ |
197 | continue; |
198 | tok &= ~TOK_SPACE; |
199 | } else if (is_space) { |
200 | /* 1st whitespace char. |
201 | * Set TOK_SPACE and replace char by ' ' */ |
202 | t = TOK_SPACE + ' '; |
203 | } |
204 | } |
205 | /* Clear EMPTY */ |
206 | tok &= ~(TOK_EMPTY + CHAR_MASK); |
207 | /* Assign char value (low 9 bits) and maybe set TOK_SPACE */ |
208 | tok |= t; |
209 | break; |
210 | } |
211 | #if 0 |
212 | bb_error_msg("fp:%p tok:%x '%c'%s%s%s%s", fp, tok, tok & 0xff |
213 | , tok & TOK_EOF ? " EOF" : "" |
214 | , tok & TOK_EOL ? " EOL" : "" |
215 | , tok & TOK_EMPTY ? " EMPTY" : "" |
216 | , tok & TOK_SPACE ? " SPACE" : "" |
217 | ); |
218 | #endif |
219 | return tok; |
220 | } |
221 | |
222 | struct cand { |
223 | int x; |
224 | int y; |
225 | int pred; |
226 | }; |
227 | |
228 | static int search(const int *c, int k, int y, const struct cand *list) |
229 | { |
230 | int i, j; |
231 | |
232 | if (list[c[k]].y < y) /* quick look for typical case */ |
233 | return k + 1; |
234 | |
235 | for (i = 0, j = k + 1;;) { |
236 | const int l = (i + j) >> 1; |
237 | if (l > i) { |
238 | const int t = list[c[l]].y; |
239 | if (t > y) |
240 | j = l; |
241 | else if (t < y) |
242 | i = l; |
243 | else |
244 | return l; |
245 | } else |
246 | return l + 1; |
247 | } |
248 | } |
249 | |
250 | static unsigned isqrt(unsigned n) |
251 | { |
252 | unsigned x = 1; |
253 | while (1) { |
254 | const unsigned y = x; |
255 | x = ((n / x) + x) >> 1; |
256 | if (x <= (y + 1) && x >= (y - 1)) |
257 | return x; |
258 | } |
259 | } |
260 | |
261 | static void stone(const int *a, int n, const int *b, int *J, int pref) |
262 | { |
263 | const unsigned isq = isqrt(n); |
264 | const unsigned bound = |
265 | (option_mask32 & FLAG(d)) ? UINT_MAX : MAX(256, isq); |
266 | int clen = 1; |
267 | int clistlen = 100; |
268 | int k = 0; |
269 | struct cand *clist = xzalloc(clistlen * sizeof(clist[0])); |
270 | struct cand cand; |
271 | struct cand *q; |
272 | int *klist = xzalloc((n + 2) * sizeof(klist[0])); |
273 | /*clist[0] = (struct cand){0}; - xzalloc did it */ |
274 | /*klist[0] = 0; */ |
275 | |
276 | for (cand.x = 1; cand.x <= n; cand.x++) { |
277 | int j = a[cand.x], oldl = 0; |
278 | unsigned numtries = 0; |
279 | if (j == 0) |
280 | continue; |
281 | cand.y = -b[j]; |
282 | cand.pred = klist[0]; |
283 | do { |
284 | int l, tc; |
285 | if (cand.y <= clist[cand.pred].y) |
286 | continue; |
287 | l = search(klist, k, cand.y, clist); |
288 | if (l != oldl + 1) |
289 | cand.pred = klist[l - 1]; |
290 | if (l <= k && clist[klist[l]].y <= cand.y) |
291 | continue; |
292 | if (clen == clistlen) { |
293 | clistlen = clistlen * 11 / 10; |
294 | clist = xrealloc(clist, clistlen * sizeof(clist[0])); |
295 | } |
296 | clist[clen] = cand; |
297 | tc = klist[l]; |
298 | klist[l] = clen++; |
299 | if (l <= k) { |
300 | cand.pred = tc; |
301 | oldl = l; |
302 | numtries++; |
303 | } else { |
304 | k++; |
305 | break; |
306 | } |
307 | } while ((cand.y = b[++j]) > 0 && numtries < bound); |
308 | } |
309 | /* Unravel */ |
310 | for (q = clist + klist[k]; q->y; q = clist + q->pred) |
311 | J[q->x + pref] = q->y + pref; |
312 | free(klist); |
313 | free(clist); |
314 | } |
315 | |
316 | struct line { |
317 | /* 'serial' is not used in the begining, so we reuse it |
318 | * to store line offsets, thus reducing memory pressure |
319 | */ |
320 | union { |
321 | unsigned serial; |
322 | off_t offset; |
323 | }; |
324 | unsigned value; |
325 | }; |
326 | |
327 | static void equiv(struct line *a, int n, struct line *b, int m, int *c) |
328 | { |
329 | int i = 1, j = 1; |
330 | |
331 | while (i <= n && j <= m) { |
332 | if (a[i].value < b[j].value) |
333 | a[i++].value = 0; |
334 | else if (a[i].value == b[j].value) |
335 | a[i++].value = j; |
336 | else |
337 | j++; |
338 | } |
339 | while (i <= n) |
340 | a[i++].value = 0; |
341 | b[m + 1].value = 0; |
342 | j = 0; |
343 | while (++j <= m) { |
344 | c[j] = -b[j].serial; |
345 | while (b[j + 1].value == b[j].value) { |
346 | j++; |
347 | c[j] = b[j].serial; |
348 | } |
349 | } |
350 | c[j] = -1; |
351 | } |
352 | |
353 | static void unsort(const struct line *f, int l, int *b) |
354 | { |
355 | int i; |
356 | int *a = xmalloc((l + 1) * sizeof(a[0])); |
357 | for (i = 1; i <= l; i++) |
358 | a[f[i].serial] = f[i].value; |
359 | for (i = 1; i <= l; i++) |
360 | b[i] = a[i]; |
361 | free(a); |
362 | } |
363 | |
364 | static int line_compar(const void *a, const void *b) |
365 | { |
366 | #define l0 ((const struct line*)a) |
367 | #define l1 ((const struct line*)b) |
368 | int r = l0->value - l1->value; |
369 | if (r) |
370 | return r; |
371 | return l0->serial - l1->serial; |
372 | #undef l0 |
373 | #undef l1 |
374 | } |
375 | |
376 | static void fetch(FILE_and_pos_t *ft, const off_t *ix, int a, int b, int ch) |
377 | { |
378 | int i, j, col; |
379 | for (i = a; i <= b; i++) { |
380 | seek_ft(ft, ix[i - 1]); |
381 | putchar(ch); |
382 | if (option_mask32 & FLAG(T)) |
383 | putchar('\t'); |
384 | for (j = 0, col = 0; j < ix[i] - ix[i - 1]; j++) { |
385 | int c = fgetc(ft->ft_fp); |
386 | if (c == EOF) { |
387 | printf("\n\\ No newline at end of file\n"); |
388 | return; |
389 | } |
390 | ft->ft_pos++; |
391 | if (c == '\t' && (option_mask32 & FLAG(t))) |
392 | do putchar(' '); while (++col & 7); |
393 | else { |
394 | putchar(c); |
395 | col++; |
396 | } |
397 | } |
398 | } |
399 | } |
400 | |
401 | /* Creates the match vector J, where J[i] is the index |
402 | * of the line in the new file corresponding to the line i |
403 | * in the old file. Lines start at 1 instead of 0, that value |
404 | * being used instead to denote no corresponding line. |
405 | * This vector is dynamically allocated and must be freed by the caller. |
406 | * |
407 | * * fp is an input parameter, where fp[0] and fp[1] are the open |
408 | * old file and new file respectively. |
409 | * * nlen is an output variable, where nlen[0] and nlen[1] |
410 | * gets the number of lines in the old and new file respectively. |
411 | * * ix is an output variable, where ix[0] and ix[1] gets |
412 | * assigned dynamically allocated vectors of the offsets of the lines |
413 | * of the old and new file respectively. These must be freed by the caller. |
414 | */ |
415 | static NOINLINE int *create_J(FILE_and_pos_t ft[2], int nlen[2], off_t *ix[2]) |
416 | { |
417 | int *J, slen[2], *class, *member; |
418 | struct line *nfile[2], *sfile[2]; |
419 | int pref = 0, suff = 0, i, j, delta; |
420 | |
421 | /* Lines of both files are hashed, and in the process |
422 | * their offsets are stored in the array ix[fileno] |
423 | * where fileno == 0 points to the old file, and |
424 | * fileno == 1 points to the new one. |
425 | */ |
426 | for (i = 0; i < 2; i++) { |
427 | unsigned hash; |
428 | token_t tok; |
429 | size_t sz = 100; |
430 | nfile[i] = xmalloc((sz + 3) * sizeof(nfile[i][0])); |
431 | /* ft gets here without the correct position, cant use seek_ft */ |
432 | ft[i].ft_pos = 0; |
433 | fseeko(ft[i].ft_fp, 0, SEEK_SET); |
434 | |
435 | nlen[i] = 0; |
436 | /* We could zalloc nfile, but then zalloc starts showing in gprof at ~1% */ |
437 | nfile[i][0].offset = 0; |
438 | goto start; /* saves code */ |
439 | while (1) { |
440 | tok = read_token(&ft[i], tok); |
441 | if (!(tok & TOK_EMPTY)) { |
442 | /* Hash algorithm taken from Robert Sedgewick, Algorithms in C, 3d ed., p 578. */ |
443 | /*hash = hash * 128 - hash + TOK2CHAR(tok); |
444 | * gcc insists on optimizing above to "hash * 127 + ...", thus... */ |
445 | unsigned o = hash - TOK2CHAR(tok); |
446 | hash = hash * 128 - o; /* we want SPEED here */ |
447 | continue; |
448 | } |
449 | if (nlen[i]++ == sz) { |
450 | sz = sz * 3 / 2; |
451 | nfile[i] = xrealloc(nfile[i], (sz + 3) * sizeof(nfile[i][0])); |
452 | } |
453 | /* line_compar needs hashes fit into positive int */ |
454 | nfile[i][nlen[i]].value = hash & INT_MAX; |
455 | /* like ftello(ft[i].ft_fp) but faster (avoids lseek syscall) */ |
456 | nfile[i][nlen[i]].offset = ft[i].ft_pos; |
457 | if (tok & TOK_EOF) { |
458 | /* EOF counts as a token, so we have to adjust it here */ |
459 | nfile[i][nlen[i]].offset++; |
460 | break; |
461 | } |
462 | start: |
463 | hash = tok = 0; |
464 | } |
465 | /* Exclude lone EOF line from the end of the file, to make fetch()'s job easier */ |
466 | if (nfile[i][nlen[i]].offset - nfile[i][nlen[i] - 1].offset == 1) |
467 | nlen[i]--; |
468 | /* Now we copy the line offsets into ix */ |
469 | ix[i] = xmalloc((nlen[i] + 2) * sizeof(ix[i][0])); |
470 | for (j = 0; j < nlen[i] + 1; j++) |
471 | ix[i][j] = nfile[i][j].offset; |
472 | } |
473 | |
474 | /* length of prefix and suffix is calculated */ |
475 | for (; pref < nlen[0] && pref < nlen[1] && |
476 | nfile[0][pref + 1].value == nfile[1][pref + 1].value; |
477 | pref++); |
478 | for (; suff < nlen[0] - pref && suff < nlen[1] - pref && |
479 | nfile[0][nlen[0] - suff].value == nfile[1][nlen[1] - suff].value; |
480 | suff++); |
481 | /* Arrays are pruned by the suffix and prefix lenght, |
482 | * the result being sorted and stored in sfile[fileno], |
483 | * and their sizes are stored in slen[fileno] |
484 | */ |
485 | for (j = 0; j < 2; j++) { |
486 | sfile[j] = nfile[j] + pref; |
487 | slen[j] = nlen[j] - pref - suff; |
488 | for (i = 0; i <= slen[j]; i++) |
489 | sfile[j][i].serial = i; |
490 | qsort(sfile[j] + 1, slen[j], sizeof(*sfile[j]), line_compar); |
491 | } |
492 | /* nfile arrays are reused to reduce memory pressure |
493 | * The #if zeroed out section performs the same task as the |
494 | * one in the #else section. |
495 | * Peak memory usage is higher, but one array copy is avoided |
496 | * by not using unsort() |
497 | */ |
498 | #if 0 |
499 | member = xmalloc((slen[1] + 2) * sizeof(member[0])); |
500 | equiv(sfile[0], slen[0], sfile[1], slen[1], member); |
501 | free(nfile[1]); |
502 | |
503 | class = xmalloc((slen[0] + 1) * sizeof(class[0])); |
504 | for (i = 1; i <= slen[0]; i++) /* Unsorting */ |
505 | class[sfile[0][i].serial] = sfile[0][i].value; |
506 | free(nfile[0]); |
507 | #else |
508 | member = (int *)nfile[1]; |
509 | equiv(sfile[0], slen[0], sfile[1], slen[1], member); |
510 | member = xrealloc(member, (slen[1] + 2) * sizeof(member[0])); |
511 | |
512 | class = (int *)nfile[0]; |
513 | unsort(sfile[0], slen[0], (int *)nfile[0]); |
514 | class = xrealloc(class, (slen[0] + 2) * sizeof(class[0])); |
515 | #endif |
516 | J = xmalloc((nlen[0] + 2) * sizeof(J[0])); |
517 | /* The elements of J which fall inside the prefix and suffix regions |
518 | * are marked as unchanged, while the ones which fall outside |
519 | * are initialized with 0 (no matches), so that function stone can |
520 | * then assign them their right values |
521 | */ |
522 | for (i = 0, delta = nlen[1] - nlen[0]; i <= nlen[0]; i++) |
523 | J[i] = i <= pref ? i : |
524 | i > (nlen[0] - suff) ? (i + delta) : 0; |
525 | /* Here the magic is performed */ |
526 | stone(class, slen[0], member, J, pref); |
527 | J[nlen[0] + 1] = nlen[1] + 1; |
528 | |
529 | free(class); |
530 | free(member); |
531 | |
532 | /* Both files are rescanned, in an effort to find any lines |
533 | * which, due to limitations intrinsic to any hashing algorithm, |
534 | * are different but ended up confounded as the same |
535 | */ |
536 | for (i = 1; i <= nlen[0]; i++) { |
537 | if (!J[i]) |
538 | continue; |
539 | |
540 | seek_ft(&ft[0], ix[0][i - 1]); |
541 | seek_ft(&ft[1], ix[1][J[i] - 1]); |
542 | |
543 | for (j = J[i]; i <= nlen[0] && J[i] == j; i++, j++) { |
544 | token_t tok0 = 0, tok1 = 0; |
545 | do { |
546 | tok0 = read_token(&ft[0], tok0); |
547 | tok1 = read_token(&ft[1], tok1); |
548 | |
549 | if (((tok0 ^ tok1) & TOK_EMPTY) != 0 /* one is empty (not both) */ |
550 | || (!(tok0 & TOK_EMPTY) && TOK2CHAR(tok0) != TOK2CHAR(tok1)) |
551 | ) { |
552 | J[i] = 0; /* Break the correspondence */ |
553 | } |
554 | } while (!(tok0 & tok1 & TOK_EMPTY)); |
555 | } |
556 | } |
557 | |
558 | return J; |
559 | } |
560 | |
561 | static bool diff(FILE* fp[2], char *file[2]) |
562 | { |
563 | int nlen[2]; |
564 | off_t *ix[2]; |
565 | FILE_and_pos_t ft[2]; |
566 | typedef struct { int a, b; } vec_t[2]; |
567 | vec_t *vec = NULL; |
568 | int i = 1, j, k, idx = -1; |
569 | bool anychange = false; |
570 | int *J; |
571 | |
572 | ft[0].ft_fp = fp[0]; |
573 | ft[1].ft_fp = fp[1]; |
574 | /* note that ft[i].ft_pos is unintitalized, create_J() |
575 | * must not assume otherwise */ |
576 | J = create_J(ft, nlen, ix); |
577 | |
578 | do { |
579 | bool nonempty = false; |
580 | |
581 | while (1) { |
582 | vec_t v; |
583 | |
584 | for (v[0].a = i; v[0].a <= nlen[0] && J[v[0].a] == J[v[0].a - 1] + 1; v[0].a++) |
585 | continue; |
586 | v[1].a = J[v[0].a - 1] + 1; |
587 | |
588 | for (v[0].b = v[0].a - 1; v[0].b < nlen[0] && !J[v[0].b + 1]; v[0].b++) |
589 | continue; |
590 | v[1].b = J[v[0].b + 1] - 1; |
591 | /* |
592 | * Indicate that there is a difference between lines a and b of the 'from' file |
593 | * to get to lines c to d of the 'to' file. If a is greater than b then there |
594 | * are no lines in the 'from' file involved and this means that there were |
595 | * lines appended (beginning at b). If c is greater than d then there are |
596 | * lines missing from the 'to' file. |
597 | */ |
598 | if (v[0].a <= v[0].b || v[1].a <= v[1].b) { |
599 | /* |
600 | * If this change is more than 'context' lines from the |
601 | * previous change, dump the record and reset it. |
602 | */ |
603 | int ct = (2 * opt_U_context) + 1; |
604 | if (idx >= 0 |
605 | && v[0].a > vec[idx][0].b + ct |
606 | && v[1].a > vec[idx][1].b + ct |
607 | ) { |
608 | break; |
609 | } |
610 | |
611 | for (j = 0; j < 2; j++) |
612 | for (k = v[j].a; k < v[j].b; k++) |
613 | nonempty |= (ix[j][k+1] - ix[j][k] != 1); |
614 | |
615 | vec = xrealloc_vector(vec, 6, ++idx); |
616 | memcpy(vec[idx], v, sizeof(v)); |
617 | } |
618 | |
619 | i = v[0].b + 1; |
620 | if (i > nlen[0]) |
621 | break; |
622 | J[v[0].b] = v[1].b; |
623 | } |
624 | if (idx < 0 || ((option_mask32 & FLAG(B)) && !nonempty)) |
625 | goto cont; |
626 | if (!(option_mask32 & FLAG(q))) { |
627 | int lowa; |
628 | vec_t span, *cvp = vec; |
629 | |
630 | if (!anychange) { |
631 | /* Print the context/unidiff header first time through */ |
632 | printf("--- %s\n", label[0] ? label[0] : file[0]); |
633 | printf("+++ %s\n", label[1] ? label[1] : file[1]); |
634 | } |
635 | |
636 | printf("@@"); |
637 | for (j = 0; j < 2; j++) { |
638 | int a = span[j].a = MAX(1, (*cvp)[j].a - opt_U_context); |
639 | int b = span[j].b = MIN(nlen[j], vec[idx][j].b + opt_U_context); |
640 | |
641 | printf(" %c%d", j ? '+' : '-', MIN(a, b)); |
642 | if (a == b) |
643 | continue; |
644 | printf(",%d", (a < b) ? b - a + 1 : 0); |
645 | } |
646 | printf(" @@\n"); |
647 | /* |
648 | * Output changes in "unified" diff format--the old and new lines |
649 | * are printed together. |
650 | */ |
651 | for (lowa = span[0].a; ; lowa = (*cvp++)[0].b + 1) { |
652 | bool end = cvp > &vec[idx]; |
653 | fetch(&ft[0], ix[0], lowa, end ? span[0].b : (*cvp)[0].a - 1, ' '); |
654 | if (end) |
655 | break; |
656 | for (j = 0; j < 2; j++) |
657 | fetch(&ft[j], ix[j], (*cvp)[j].a, (*cvp)[j].b, j ? '+' : '-'); |
658 | } |
659 | } |
660 | anychange = true; |
661 | cont: |
662 | idx = -1; |
663 | } while (i <= nlen[0]); |
664 | |
665 | free(vec); |
666 | free(ix[0]); |
667 | free(ix[1]); |
668 | free(J); |
669 | return anychange; |
670 | } |
671 | |
672 | static int diffreg(char *file[2]) |
673 | { |
674 | FILE *fp[2] = { stdin, stdin }; |
675 | bool binary = false, differ = false; |
676 | int status = STATUS_SAME, i; |
677 | |
678 | for (i = 0; i < 2; i++) { |
679 | int fd = open_or_warn_stdin(file[i]); |
680 | if (fd == -1) |
681 | goto out; |
682 | /* Our diff implementation is using seek. |
683 | * When we meet non-seekable file, we must make a temp copy. |
684 | */ |
685 | if (lseek(fd, 0, SEEK_SET) == -1 && errno == ESPIPE) { |
686 | char name[] = "/tmp/difXXXXXX"; |
687 | int fd_tmp = mkstemp(name); |
688 | if (fd_tmp < 0) |
689 | bb_perror_msg_and_die("mkstemp"); |
690 | unlink(name); |
691 | if (bb_copyfd_eof(fd, fd_tmp) < 0) |
692 | xfunc_die(); |
693 | if (fd) /* Prevents closing of stdin */ |
694 | close(fd); |
695 | fd = fd_tmp; |
696 | } |
697 | fp[i] = fdopen(fd, "r"); |
698 | } |
699 | |
700 | while (1) { |
701 | const size_t sz = COMMON_BUFSIZE / 2; |
702 | char *const buf0 = bb_common_bufsiz1; |
703 | char *const buf1 = buf0 + sz; |
704 | int j, k; |
705 | i = fread(buf0, 1, sz, fp[0]); |
706 | j = fread(buf1, 1, sz, fp[1]); |
707 | if (i != j) { |
708 | differ = true; |
709 | i = MIN(i, j); |
710 | } |
711 | if (i == 0) |
712 | break; |
713 | for (k = 0; k < i; k++) { |
714 | if (!buf0[k] || !buf1[k]) |
715 | binary = true; |
716 | if (buf0[k] != buf1[k]) |
717 | differ = true; |
718 | } |
719 | } |
720 | if (differ) { |
721 | if (binary && !(option_mask32 & FLAG(a))) |
722 | status = STATUS_BINARY; |
723 | else if (diff(fp, file)) |
724 | status = STATUS_DIFFER; |
725 | } |
726 | if (status != STATUS_SAME) |
727 | exit_status |= 1; |
728 | out: |
729 | fclose_if_not_stdin(fp[0]); |
730 | fclose_if_not_stdin(fp[1]); |
731 | |
732 | return status; |
733 | } |
734 | |
735 | static void print_status(int status, char *path[2]) |
736 | { |
737 | switch (status) { |
738 | case STATUS_BINARY: |
739 | case STATUS_DIFFER: |
740 | if ((option_mask32 & FLAG(q)) || status == STATUS_BINARY) |
741 | printf("Files %s and %s differ\n", path[0], path[1]); |
742 | break; |
743 | case STATUS_SAME: |
744 | if (option_mask32 & FLAG(s)) |
745 | printf("Files %s and %s are identical\n", path[0], path[1]); |
746 | break; |
747 | } |
748 | } |
749 | |
750 | #if ENABLE_FEATURE_DIFF_DIR |
751 | struct dlist { |
752 | size_t len; |
753 | int s, e; |
754 | char **dl; |
755 | }; |
756 | |
757 | /* This function adds a filename to dl, the directory listing. */ |
758 | static int FAST_FUNC add_to_dirlist(const char *filename, |
759 | struct stat *sb UNUSED_PARAM, |
760 | void *userdata, int depth UNUSED_PARAM) |
761 | { |
762 | struct dlist *const l = userdata; |
763 | l->dl = xrealloc_vector(l->dl, 6, l->e); |
764 | /* + 1 skips "/" after dirname */ |
765 | l->dl[l->e] = xstrdup(filename + l->len + 1); |
766 | l->e++; |
767 | return TRUE; |
768 | } |
769 | |
770 | /* If recursion is not set, this function adds the directory |
771 | * to the list and prevents recursive_action from recursing into it. |
772 | */ |
773 | static int FAST_FUNC skip_dir(const char *filename, |
774 | struct stat *sb, void *userdata, |
775 | int depth) |
776 | { |
777 | if (!(option_mask32 & FLAG(r)) && depth) { |
778 | add_to_dirlist(filename, sb, userdata, depth); |
779 | return SKIP; |
780 | } |
781 | return TRUE; |
782 | } |
783 | |
784 | static void diffdir(char *p[2], const char *s_start) |
785 | { |
786 | struct dlist list[2]; |
787 | int i; |
788 | |
789 | memset(&list, 0, sizeof(list)); |
790 | for (i = 0; i < 2; i++) { |
791 | /*list[i].s = list[i].e = 0; - memset did it */ |
792 | /*list[i].dl = NULL; */ |
793 | |
794 | /* We need to trim root directory prefix. |
795 | * Using list.len to specify its length, |
796 | * add_to_dirlist will remove it. */ |
797 | list[i].len = strlen(p[i]); |
798 | recursive_action(p[i], ACTION_RECURSE | ACTION_FOLLOWLINKS, |
799 | add_to_dirlist, skip_dir, &list[i], 0); |
800 | /* Sort dl alphabetically. |
801 | * GNU diff does this ignoring any number of trailing dots. |
802 | * We don't, so for us dotted files almost always are |
803 | * first on the list. |
804 | */ |
805 | qsort_string_vector(list[i].dl, list[i].e); |
806 | /* If -S was set, find the starting point. */ |
807 | if (!s_start) |
808 | continue; |
809 | while (list[i].s < list[i].e && strcmp(list[i].dl[list[i].s], s_start) < 0) |
810 | list[i].s++; |
811 | } |
812 | /* Now that both dirlist1 and dirlist2 contain sorted directory |
813 | * listings, we can start to go through dirlist1. If both listings |
814 | * contain the same file, then do a normal diff. Otherwise, behaviour |
815 | * is determined by whether the -N flag is set. */ |
816 | while (1) { |
817 | char *dp[2]; |
818 | int pos; |
819 | int k; |
820 | |
821 | dp[0] = list[0].s < list[0].e ? list[0].dl[list[0].s] : NULL; |
822 | dp[1] = list[1].s < list[1].e ? list[1].dl[list[1].s] : NULL; |
823 | if (!dp[0] && !dp[1]) |
824 | break; |
825 | pos = !dp[0] ? 1 : (!dp[1] ? -1 : strcmp(dp[0], dp[1])); |
826 | k = pos > 0; |
827 | if (pos && !(option_mask32 & FLAG(N))) |
828 | printf("Only in %s: %s\n", p[k], dp[k]); |
829 | else { |
830 | char *fullpath[2], *path[2]; /* if -N */ |
831 | |
832 | for (i = 0; i < 2; i++) { |
833 | if (pos == 0 || i == k) { |
834 | path[i] = fullpath[i] = concat_path_file(p[i], dp[i]); |
835 | stat(fullpath[i], &stb[i]); |
836 | } else { |
837 | fullpath[i] = concat_path_file(p[i], dp[1 - i]); |
838 | path[i] = (char *)bb_dev_null; |
839 | } |
840 | } |
841 | if (pos) |
842 | stat(fullpath[k], &stb[1 - k]); |
843 | |
844 | if (S_ISDIR(stb[0].st_mode) && S_ISDIR(stb[1].st_mode)) |
845 | printf("Common subdirectories: %s and %s\n", fullpath[0], fullpath[1]); |
846 | else if (!S_ISREG(stb[0].st_mode) && !S_ISDIR(stb[0].st_mode)) |
847 | printf("File %s is not a regular file or directory and was skipped\n", fullpath[0]); |
848 | else if (!S_ISREG(stb[1].st_mode) && !S_ISDIR(stb[1].st_mode)) |
849 | printf("File %s is not a regular file or directory and was skipped\n", fullpath[1]); |
850 | else if (S_ISDIR(stb[0].st_mode) != S_ISDIR(stb[1].st_mode)) { |
851 | if (S_ISDIR(stb[0].st_mode)) |
852 | printf("File %s is a %s while file %s is a %s\n", fullpath[0], "directory", fullpath[1], "regular file"); |
853 | else |
854 | printf("File %s is a %s while file %s is a %s\n", fullpath[0], "regular file", fullpath[1], "directory"); |
855 | } else |
856 | print_status(diffreg(path), fullpath); |
857 | |
858 | free(fullpath[0]); |
859 | free(fullpath[1]); |
860 | } |
861 | free(dp[k]); |
862 | list[k].s++; |
863 | if (pos == 0) { |
864 | free(dp[1 - k]); |
865 | list[1 - k].s++; |
866 | } |
867 | } |
868 | if (ENABLE_FEATURE_CLEAN_UP) { |
869 | free(list[0].dl); |
870 | free(list[1].dl); |
871 | } |
872 | } |
873 | #endif |
874 | |
875 | #if ENABLE_FEATURE_DIFF_LONG_OPTIONS |
876 | static const char diff_longopts[] ALIGN1 = |
877 | "ignore-case\0" No_argument "i" |
878 | "ignore-tab-expansion\0" No_argument "E" |
879 | "ignore-space-change\0" No_argument "b" |
880 | "ignore-all-space\0" No_argument "w" |
881 | "ignore-blank-lines\0" No_argument "B" |
882 | "text\0" No_argument "a" |
883 | "unified\0" Required_argument "U" |
884 | "label\0" Required_argument "L" |
885 | "show-c-function\0" No_argument "p" |
886 | "brief\0" No_argument "q" |
887 | "expand-tabs\0" No_argument "t" |
888 | "initial-tab\0" No_argument "T" |
889 | "recursive\0" No_argument "r" |
890 | "new-file\0" No_argument "N" |
891 | "report-identical-files\0" No_argument "s" |
892 | "starting-file\0" Required_argument "S" |
893 | "minimal\0" No_argument "d" |
894 | ; |
895 | #endif |
896 | |
897 | int diff_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
898 | int diff_main(int argc UNUSED_PARAM, char **argv) |
899 | { |
900 | int gotstdin = 0, i; |
901 | char *file[2], *s_start = NULL; |
902 | llist_t *L_arg = NULL; |
903 | |
904 | INIT_G(); |
905 | |
906 | /* exactly 2 params; collect multiple -L <label>; -U N */ |
907 | opt_complementary = "=2:L::U+"; |
908 | #if ENABLE_FEATURE_DIFF_LONG_OPTIONS |
909 | applet_long_options = diff_longopts; |
910 | #endif |
911 | getopt32(argv, "abdiL:NqrsS:tTU:wupBE", |
912 | &L_arg, &s_start, &opt_U_context); |
913 | argv += optind; |
914 | while (L_arg) |
915 | label[!!label[0]] = llist_pop(&L_arg); |
916 | xfunc_error_retval = 2; |
917 | for (i = 0; i < 2; i++) { |
918 | file[i] = argv[i]; |
919 | /* Compat: "diff file name_which_doesnt_exist" exits with 2 */ |
920 | if (LONE_DASH(file[i])) { |
921 | fstat(STDIN_FILENO, &stb[i]); |
922 | gotstdin++; |
923 | } else |
924 | xstat(file[i], &stb[i]); |
925 | } |
926 | xfunc_error_retval = 1; |
927 | if (gotstdin && (S_ISDIR(stb[0].st_mode) || S_ISDIR(stb[1].st_mode))) |
928 | bb_error_msg_and_die("can't compare stdin to a directory"); |
929 | |
930 | if (S_ISDIR(stb[0].st_mode) && S_ISDIR(stb[1].st_mode)) { |
931 | #if ENABLE_FEATURE_DIFF_DIR |
932 | diffdir(file, s_start); |
933 | #else |
934 | bb_error_msg_and_die("no support for directory comparison"); |
935 | #endif |
936 | } else { |
937 | bool dirfile = S_ISDIR(stb[0].st_mode) || S_ISDIR(stb[1].st_mode); |
938 | bool dir = S_ISDIR(stb[1].st_mode); |
939 | if (dirfile) { |
940 | const char *slash = strrchr(file[!dir], '/'); |
941 | file[dir] = concat_path_file(file[dir], slash ? slash + 1 : file[!dir]); |
942 | xstat(file[dir], &stb[dir]); |
943 | } |
944 | /* diffreg can get non-regular files here */ |
945 | print_status(gotstdin > 1 ? STATUS_SAME : diffreg(file), file); |
946 | |
947 | if (dirfile) |
948 | free(file[dir]); |
949 | } |
950 | |
951 | return exit_status; |
952 | } |