1 | /* |
2 | * LibXDiff by Davide Libenzi ( File Differential Library ) |
3 | * Copyright (C) 2003 Davide Libenzi |
4 | * |
5 | * This library is free software; you can redistribute it and/or |
6 | * modify it under the terms of the GNU Lesser General Public |
7 | * License as published by the Free Software Foundation; either |
8 | * version 2.1 of the License, or (at your option) any later version. |
9 | * |
10 | * This library is distributed in the hope that it will be useful, |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
13 | * Lesser General Public License for more details. |
14 | * |
15 | * You should have received a copy of the GNU Lesser General Public |
16 | * License along with this library; if not, see |
17 | * <http://www.gnu.org/licenses/>. |
18 | * |
19 | * Davide Libenzi <davidel@xmailserver.org> |
20 | * |
21 | */ |
22 | |
23 | #include "xinclude.h" |
24 | |
25 | |
26 | #define XDL_KPDIS_RUN 4 |
27 | #define XDL_MAX_EQLIMIT 1024 |
28 | #define XDL_SIMSCAN_WINDOW 100 |
29 | #define XDL_GUESS_NLINES1 256 |
30 | #define XDL_GUESS_NLINES2 20 |
31 | |
32 | |
33 | typedef struct s_xdlclass { |
34 | struct s_xdlclass *next; |
35 | unsigned long ha; |
36 | char const *line; |
37 | long size; |
38 | long idx; |
39 | long len1, len2; |
40 | } xdlclass_t; |
41 | |
42 | typedef struct s_xdlclassifier { |
43 | unsigned int hbits; |
44 | long hsize; |
45 | xdlclass_t **rchash; |
46 | chastore_t ncha; |
47 | xdlclass_t **rcrecs; |
48 | long alloc; |
49 | long count; |
50 | long flags; |
51 | } xdlclassifier_t; |
52 | |
53 | |
54 | |
55 | |
56 | static int xdl_init_classifier(xdlclassifier_t *cf, long size, long flags); |
57 | static void xdl_free_classifier(xdlclassifier_t *cf); |
58 | static int xdl_classify_record(unsigned int pass, xdlclassifier_t *cf, xrecord_t **rhash, |
59 | unsigned int hbits, xrecord_t *rec); |
60 | static int xdl_prepare_ctx(unsigned int pass, mmfile_t *mf, long narec, xpparam_t const *xpp, |
61 | xdlclassifier_t *cf, xdfile_t *xdf); |
62 | static void xdl_free_ctx(xdfile_t *xdf); |
63 | static int xdl_clean_mmatch(char const *dis, long i, long s, long e); |
64 | static int xdl_cleanup_records(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xdf2); |
65 | static int xdl_trim_ends(xdfile_t *xdf1, xdfile_t *xdf2); |
66 | static int xdl_optimize_ctxs(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xdf2); |
67 | |
68 | |
69 | |
70 | |
71 | static int xdl_init_classifier(xdlclassifier_t *cf, long size, long flags) { |
72 | cf->flags = flags; |
73 | |
74 | cf->hbits = xdl_hashbits((unsigned int) size); |
75 | cf->hsize = 1 << cf->hbits; |
76 | |
77 | if (xdl_cha_init(&cf->ncha, sizeof(xdlclass_t), size / 4 + 1) < 0) { |
78 | |
79 | return -1; |
80 | } |
81 | if (!(cf->rchash = (xdlclass_t **) xdl_malloc(cf->hsize * sizeof(xdlclass_t *)))) { |
82 | |
83 | xdl_cha_free(&cf->ncha); |
84 | return -1; |
85 | } |
86 | memset(cf->rchash, 0, cf->hsize * sizeof(xdlclass_t *)); |
87 | |
88 | cf->alloc = size; |
89 | if (!(cf->rcrecs = (xdlclass_t **) xdl_malloc(cf->alloc * sizeof(xdlclass_t *)))) { |
90 | |
91 | xdl_free(cf->rchash); |
92 | xdl_cha_free(&cf->ncha); |
93 | return -1; |
94 | } |
95 | |
96 | cf->count = 0; |
97 | |
98 | return 0; |
99 | } |
100 | |
101 | |
102 | static void xdl_free_classifier(xdlclassifier_t *cf) { |
103 | |
104 | xdl_free(cf->rcrecs); |
105 | xdl_free(cf->rchash); |
106 | xdl_cha_free(&cf->ncha); |
107 | } |
108 | |
109 | |
110 | static int xdl_classify_record(unsigned int pass, xdlclassifier_t *cf, xrecord_t **rhash, |
111 | unsigned int hbits, xrecord_t *rec) { |
112 | long hi; |
113 | char const *line; |
114 | xdlclass_t *rcrec; |
115 | xdlclass_t **rcrecs; |
116 | |
117 | line = rec->ptr; |
118 | hi = (long) XDL_HASHLONG(rec->ha, cf->hbits); |
119 | for (rcrec = cf->rchash[hi]; rcrec; rcrec = rcrec->next) |
120 | if (rcrec->ha == rec->ha && |
121 | xdl_recmatch(rcrec->line, rcrec->size, |
122 | rec->ptr, rec->size, cf->flags)) |
123 | break; |
124 | |
125 | if (!rcrec) { |
126 | if (!(rcrec = xdl_cha_alloc(&cf->ncha))) { |
127 | |
128 | return -1; |
129 | } |
130 | rcrec->idx = cf->count++; |
131 | if (cf->count > cf->alloc) { |
132 | cf->alloc *= 2; |
133 | if (!(rcrecs = (xdlclass_t **) xdl_realloc(cf->rcrecs, cf->alloc * sizeof(xdlclass_t *)))) { |
134 | |
135 | return -1; |
136 | } |
137 | cf->rcrecs = rcrecs; |
138 | } |
139 | cf->rcrecs[rcrec->idx] = rcrec; |
140 | rcrec->line = line; |
141 | rcrec->size = rec->size; |
142 | rcrec->ha = rec->ha; |
143 | rcrec->len1 = rcrec->len2 = 0; |
144 | rcrec->next = cf->rchash[hi]; |
145 | cf->rchash[hi] = rcrec; |
146 | } |
147 | |
148 | (pass == 1) ? rcrec->len1++ : rcrec->len2++; |
149 | |
150 | rec->ha = (unsigned long) rcrec->idx; |
151 | |
152 | hi = (long) XDL_HASHLONG(rec->ha, hbits); |
153 | rec->next = rhash[hi]; |
154 | rhash[hi] = rec; |
155 | |
156 | return 0; |
157 | } |
158 | |
159 | |
160 | static int xdl_prepare_ctx(unsigned int pass, mmfile_t *mf, long narec, xpparam_t const *xpp, |
161 | xdlclassifier_t *cf, xdfile_t *xdf) { |
162 | unsigned int hbits; |
163 | long nrec, hsize, bsize; |
164 | unsigned long hav; |
165 | char const *blk, *cur, *top, *prev; |
166 | xrecord_t *crec; |
167 | xrecord_t **recs, **rrecs; |
168 | xrecord_t **rhash; |
169 | unsigned long *ha; |
170 | char *rchg; |
171 | long *rindex; |
172 | |
173 | ha = NULL; |
174 | rindex = NULL; |
175 | rchg = NULL; |
176 | rhash = NULL; |
177 | recs = NULL; |
178 | |
179 | if (xdl_cha_init(&xdf->rcha, sizeof(xrecord_t), narec / 4 + 1) < 0) |
180 | goto abort; |
181 | if (!(recs = (xrecord_t **) xdl_malloc(narec * sizeof(xrecord_t *)))) |
182 | goto abort; |
183 | |
184 | if (XDF_DIFF_ALG(xpp->flags) == XDF_HISTOGRAM_DIFF) |
185 | hbits = hsize = 0; |
186 | else { |
187 | hbits = xdl_hashbits((unsigned int) narec); |
188 | hsize = 1 << hbits; |
189 | if (!(rhash = (xrecord_t **) xdl_malloc(hsize * sizeof(xrecord_t *)))) |
190 | goto abort; |
191 | memset(rhash, 0, hsize * sizeof(xrecord_t *)); |
192 | } |
193 | |
194 | nrec = 0; |
195 | if ((cur = blk = xdl_mmfile_first(mf, &bsize)) != NULL) { |
196 | for (top = blk + bsize; cur < top; ) { |
197 | prev = cur; |
198 | hav = xdl_hash_record(&cur, top, xpp->flags); |
199 | if (nrec >= narec) { |
200 | narec *= 2; |
201 | if (!(rrecs = (xrecord_t **) xdl_realloc(recs, narec * sizeof(xrecord_t *)))) |
202 | goto abort; |
203 | recs = rrecs; |
204 | } |
205 | if (!(crec = xdl_cha_alloc(&xdf->rcha))) |
206 | goto abort; |
207 | crec->ptr = prev; |
208 | crec->size = (long) (cur - prev); |
209 | crec->ha = hav; |
210 | recs[nrec++] = crec; |
211 | |
212 | if ((XDF_DIFF_ALG(xpp->flags) != XDF_HISTOGRAM_DIFF) && |
213 | xdl_classify_record(pass, cf, rhash, hbits, crec) < 0) |
214 | goto abort; |
215 | } |
216 | } |
217 | |
218 | if (!(rchg = (char *) xdl_malloc((nrec + 2) * sizeof(char)))) |
219 | goto abort; |
220 | memset(rchg, 0, (nrec + 2) * sizeof(char)); |
221 | |
222 | if (!(rindex = (long *) xdl_malloc((nrec + 1) * sizeof(long)))) |
223 | goto abort; |
224 | if (!(ha = (unsigned long *) xdl_malloc((nrec + 1) * sizeof(unsigned long)))) |
225 | goto abort; |
226 | |
227 | xdf->nrec = nrec; |
228 | xdf->recs = recs; |
229 | xdf->hbits = hbits; |
230 | xdf->rhash = rhash; |
231 | xdf->rchg = rchg + 1; |
232 | xdf->rindex = rindex; |
233 | xdf->nreff = 0; |
234 | xdf->ha = ha; |
235 | xdf->dstart = 0; |
236 | xdf->dend = nrec - 1; |
237 | |
238 | return 0; |
239 | |
240 | abort: |
241 | xdl_free(ha); |
242 | xdl_free(rindex); |
243 | xdl_free(rchg); |
244 | xdl_free(rhash); |
245 | xdl_free(recs); |
246 | xdl_cha_free(&xdf->rcha); |
247 | return -1; |
248 | } |
249 | |
250 | |
251 | static void xdl_free_ctx(xdfile_t *xdf) { |
252 | |
253 | xdl_free(xdf->rhash); |
254 | xdl_free(xdf->rindex); |
255 | xdl_free(xdf->rchg - 1); |
256 | xdl_free(xdf->ha); |
257 | xdl_free(xdf->recs); |
258 | xdl_cha_free(&xdf->rcha); |
259 | } |
260 | |
261 | |
262 | int xdl_prepare_env(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp, |
263 | xdfenv_t *xe) { |
264 | long enl1, enl2, sample; |
265 | xdlclassifier_t cf; |
266 | |
267 | memset(&cf, 0, sizeof(cf)); |
268 | |
269 | /* |
270 | * For histogram diff, we can afford a smaller sample size and |
271 | * thus a poorer estimate of the number of lines, as the hash |
272 | * table (rhash) won't be filled up/grown. The number of lines |
273 | * (nrecs) will be updated correctly anyway by |
274 | * xdl_prepare_ctx(). |
275 | */ |
276 | sample = (XDF_DIFF_ALG(xpp->flags) == XDF_HISTOGRAM_DIFF |
277 | ? XDL_GUESS_NLINES2 : XDL_GUESS_NLINES1); |
278 | |
279 | enl1 = xdl_guess_lines(mf1, sample) + 1; |
280 | enl2 = xdl_guess_lines(mf2, sample) + 1; |
281 | |
282 | if (XDF_DIFF_ALG(xpp->flags) != XDF_HISTOGRAM_DIFF && |
283 | xdl_init_classifier(&cf, enl1 + enl2 + 1, xpp->flags) < 0) |
284 | return -1; |
285 | |
286 | if (xdl_prepare_ctx(1, mf1, enl1, xpp, &cf, &xe->xdf1) < 0) { |
287 | |
288 | xdl_free_classifier(&cf); |
289 | return -1; |
290 | } |
291 | if (xdl_prepare_ctx(2, mf2, enl2, xpp, &cf, &xe->xdf2) < 0) { |
292 | |
293 | xdl_free_ctx(&xe->xdf1); |
294 | xdl_free_classifier(&cf); |
295 | return -1; |
296 | } |
297 | |
298 | if ((XDF_DIFF_ALG(xpp->flags) != XDF_PATIENCE_DIFF) && |
299 | (XDF_DIFF_ALG(xpp->flags) != XDF_HISTOGRAM_DIFF) && |
300 | xdl_optimize_ctxs(&cf, &xe->xdf1, &xe->xdf2) < 0) { |
301 | |
302 | xdl_free_ctx(&xe->xdf2); |
303 | xdl_free_ctx(&xe->xdf1); |
304 | xdl_free_classifier(&cf); |
305 | return -1; |
306 | } |
307 | |
308 | if (XDF_DIFF_ALG(xpp->flags) != XDF_HISTOGRAM_DIFF) |
309 | xdl_free_classifier(&cf); |
310 | |
311 | return 0; |
312 | } |
313 | |
314 | |
315 | void xdl_free_env(xdfenv_t *xe) { |
316 | |
317 | xdl_free_ctx(&xe->xdf2); |
318 | xdl_free_ctx(&xe->xdf1); |
319 | } |
320 | |
321 | |
322 | static int xdl_clean_mmatch(char const *dis, long i, long s, long e) { |
323 | long r, rdis0, rpdis0, rdis1, rpdis1; |
324 | |
325 | /* |
326 | * Limits the window the is examined during the similar-lines |
327 | * scan. The loops below stops when dis[i - r] == 1 (line that |
328 | * has no match), but there are corner cases where the loop |
329 | * proceed all the way to the extremities by causing huge |
330 | * performance penalties in case of big files. |
331 | */ |
332 | if (i - s > XDL_SIMSCAN_WINDOW) |
333 | s = i - XDL_SIMSCAN_WINDOW; |
334 | if (e - i > XDL_SIMSCAN_WINDOW) |
335 | e = i + XDL_SIMSCAN_WINDOW; |
336 | |
337 | /* |
338 | * Scans the lines before 'i' to find a run of lines that either |
339 | * have no match (dis[j] == 0) or have multiple matches (dis[j] > 1). |
340 | * Note that we always call this function with dis[i] > 1, so the |
341 | * current line (i) is already a multimatch line. |
342 | */ |
343 | for (r = 1, rdis0 = 0, rpdis0 = 1; (i - r) >= s; r++) { |
344 | if (!dis[i - r]) |
345 | rdis0++; |
346 | else if (dis[i - r] == 2) |
347 | rpdis0++; |
348 | else |
349 | break; |
350 | } |
351 | /* |
352 | * If the run before the line 'i' found only multimatch lines, we |
353 | * return 0 and hence we don't make the current line (i) discarded. |
354 | * We want to discard multimatch lines only when they appear in the |
355 | * middle of runs with nomatch lines (dis[j] == 0). |
356 | */ |
357 | if (rdis0 == 0) |
358 | return 0; |
359 | for (r = 1, rdis1 = 0, rpdis1 = 1; (i + r) <= e; r++) { |
360 | if (!dis[i + r]) |
361 | rdis1++; |
362 | else if (dis[i + r] == 2) |
363 | rpdis1++; |
364 | else |
365 | break; |
366 | } |
367 | /* |
368 | * If the run after the line 'i' found only multimatch lines, we |
369 | * return 0 and hence we don't make the current line (i) discarded. |
370 | */ |
371 | if (rdis1 == 0) |
372 | return 0; |
373 | rdis1 += rdis0; |
374 | rpdis1 += rpdis0; |
375 | |
376 | return rpdis1 * XDL_KPDIS_RUN < (rpdis1 + rdis1); |
377 | } |
378 | |
379 | |
380 | /* |
381 | * Try to reduce the problem complexity, discard records that have no |
382 | * matches on the other file. Also, lines that have multiple matches |
383 | * might be potentially discarded if they happear in a run of discardable. |
384 | */ |
385 | static int xdl_cleanup_records(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xdf2) { |
386 | long i, nm, nreff, mlim; |
387 | xrecord_t **recs; |
388 | xdlclass_t *rcrec; |
389 | char *dis, *dis1, *dis2; |
390 | |
391 | if (!(dis = (char *) xdl_malloc(xdf1->nrec + xdf2->nrec + 2))) { |
392 | |
393 | return -1; |
394 | } |
395 | memset(dis, 0, xdf1->nrec + xdf2->nrec + 2); |
396 | dis1 = dis; |
397 | dis2 = dis1 + xdf1->nrec + 1; |
398 | |
399 | if ((mlim = xdl_bogosqrt(xdf1->nrec)) > XDL_MAX_EQLIMIT) |
400 | mlim = XDL_MAX_EQLIMIT; |
401 | for (i = xdf1->dstart, recs = &xdf1->recs[xdf1->dstart]; i <= xdf1->dend; i++, recs++) { |
402 | rcrec = cf->rcrecs[(*recs)->ha]; |
403 | nm = rcrec ? rcrec->len2 : 0; |
404 | dis1[i] = (nm == 0) ? 0: (nm >= mlim) ? 2: 1; |
405 | } |
406 | |
407 | if ((mlim = xdl_bogosqrt(xdf2->nrec)) > XDL_MAX_EQLIMIT) |
408 | mlim = XDL_MAX_EQLIMIT; |
409 | for (i = xdf2->dstart, recs = &xdf2->recs[xdf2->dstart]; i <= xdf2->dend; i++, recs++) { |
410 | rcrec = cf->rcrecs[(*recs)->ha]; |
411 | nm = rcrec ? rcrec->len1 : 0; |
412 | dis2[i] = (nm == 0) ? 0: (nm >= mlim) ? 2: 1; |
413 | } |
414 | |
415 | for (nreff = 0, i = xdf1->dstart, recs = &xdf1->recs[xdf1->dstart]; |
416 | i <= xdf1->dend; i++, recs++) { |
417 | if (dis1[i] == 1 || |
418 | (dis1[i] == 2 && !xdl_clean_mmatch(dis1, i, xdf1->dstart, xdf1->dend))) { |
419 | xdf1->rindex[nreff] = i; |
420 | xdf1->ha[nreff] = (*recs)->ha; |
421 | nreff++; |
422 | } else |
423 | xdf1->rchg[i] = 1; |
424 | } |
425 | xdf1->nreff = nreff; |
426 | |
427 | for (nreff = 0, i = xdf2->dstart, recs = &xdf2->recs[xdf2->dstart]; |
428 | i <= xdf2->dend; i++, recs++) { |
429 | if (dis2[i] == 1 || |
430 | (dis2[i] == 2 && !xdl_clean_mmatch(dis2, i, xdf2->dstart, xdf2->dend))) { |
431 | xdf2->rindex[nreff] = i; |
432 | xdf2->ha[nreff] = (*recs)->ha; |
433 | nreff++; |
434 | } else |
435 | xdf2->rchg[i] = 1; |
436 | } |
437 | xdf2->nreff = nreff; |
438 | |
439 | xdl_free(dis); |
440 | |
441 | return 0; |
442 | } |
443 | |
444 | |
445 | /* |
446 | * Early trim initial and terminal matching records. |
447 | */ |
448 | static int xdl_trim_ends(xdfile_t *xdf1, xdfile_t *xdf2) { |
449 | long i, lim; |
450 | xrecord_t **recs1, **recs2; |
451 | |
452 | recs1 = xdf1->recs; |
453 | recs2 = xdf2->recs; |
454 | for (i = 0, lim = XDL_MIN(xdf1->nrec, xdf2->nrec); i < lim; |
455 | i++, recs1++, recs2++) |
456 | if ((*recs1)->ha != (*recs2)->ha) |
457 | break; |
458 | |
459 | xdf1->dstart = xdf2->dstart = i; |
460 | |
461 | recs1 = xdf1->recs + xdf1->nrec - 1; |
462 | recs2 = xdf2->recs + xdf2->nrec - 1; |
463 | for (lim -= i, i = 0; i < lim; i++, recs1--, recs2--) |
464 | if ((*recs1)->ha != (*recs2)->ha) |
465 | break; |
466 | |
467 | xdf1->dend = xdf1->nrec - i - 1; |
468 | xdf2->dend = xdf2->nrec - i - 1; |
469 | |
470 | return 0; |
471 | } |
472 | |
473 | |
474 | static int xdl_optimize_ctxs(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xdf2) { |
475 | |
476 | if (xdl_trim_ends(xdf1, xdf2) < 0 || |
477 | xdl_cleanup_records(cf, xdf1, xdf2) < 0) { |
478 | |
479 | return -1; |
480 | } |
481 | |
482 | return 0; |
483 | } |
484 | |