Merge branch ak/svn
[git] / xdiff / xprepare.c
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, write to the Free Software
17  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
18  *
19  *  Davide Libenzi <davidel@xmailserver.org>
20  *
21  */
22
23 #include "xinclude.h"
24
25
26
27 #define XDL_KPDIS_RUN 4
28
29
30
31 typedef struct s_xdlclass {
32         struct s_xdlclass *next;
33         unsigned long ha;
34         char const *line;
35         long size;
36         long idx;
37 } xdlclass_t;
38
39 typedef struct s_xdlclassifier {
40         unsigned int hbits;
41         long hsize;
42         xdlclass_t **rchash;
43         chastore_t ncha;
44         long count;
45 } xdlclassifier_t;
46
47
48
49
50 static int xdl_init_classifier(xdlclassifier_t *cf, long size);
51 static void xdl_free_classifier(xdlclassifier_t *cf);
52 static int xdl_classify_record(xdlclassifier_t *cf, xrecord_t **rhash, unsigned int hbits,
53                                xrecord_t *rec);
54 static int xdl_prepare_ctx(mmfile_t *mf, long narec, xpparam_t const *xpp,
55                            xdlclassifier_t *cf, xdfile_t *xdf);
56 static void xdl_free_ctx(xdfile_t *xdf);
57 static int xdl_clean_mmatch(char const *dis, long i, long s, long e);
58 static int xdl_cleanup_records(xdfile_t *xdf1, xdfile_t *xdf2);
59 static int xdl_trim_ends(xdfile_t *xdf1, xdfile_t *xdf2);
60 static int xdl_optimize_ctxs(xdfile_t *xdf1, xdfile_t *xdf2);
61
62
63
64
65 static int xdl_init_classifier(xdlclassifier_t *cf, long size) {
66         long i;
67
68         cf->hbits = xdl_hashbits((unsigned int) size);
69         cf->hsize = 1 << cf->hbits;
70
71         if (xdl_cha_init(&cf->ncha, sizeof(xdlclass_t), size / 4 + 1) < 0) {
72
73                 return -1;
74         }
75         if (!(cf->rchash = (xdlclass_t **) xdl_malloc(cf->hsize * sizeof(xdlclass_t *)))) {
76
77                 xdl_cha_free(&cf->ncha);
78                 return -1;
79         }
80         for (i = 0; i < cf->hsize; i++)
81                 cf->rchash[i] = NULL;
82
83         cf->count = 0;
84
85         return 0;
86 }
87
88
89 static void xdl_free_classifier(xdlclassifier_t *cf) {
90
91         xdl_free(cf->rchash);
92         xdl_cha_free(&cf->ncha);
93 }
94
95
96 static int xdl_classify_record(xdlclassifier_t *cf, xrecord_t **rhash, unsigned int hbits,
97                                xrecord_t *rec) {
98         long hi;
99         char const *line;
100         xdlclass_t *rcrec;
101
102         line = rec->ptr;
103         hi = (long) XDL_HASHLONG(rec->ha, cf->hbits);
104         for (rcrec = cf->rchash[hi]; rcrec; rcrec = rcrec->next)
105                 if (rcrec->ha == rec->ha && rcrec->size == rec->size &&
106                     !memcmp(line, rcrec->line, rec->size))
107                         break;
108
109         if (!rcrec) {
110                 if (!(rcrec = xdl_cha_alloc(&cf->ncha))) {
111
112                         return -1;
113                 }
114                 rcrec->idx = cf->count++;
115                 rcrec->line = line;
116                 rcrec->size = rec->size;
117                 rcrec->ha = rec->ha;
118                 rcrec->next = cf->rchash[hi];
119                 cf->rchash[hi] = rcrec;
120         }
121
122         rec->ha = (unsigned long) rcrec->idx;
123
124         hi = (long) XDL_HASHLONG(rec->ha, hbits);
125         rec->next = rhash[hi];
126         rhash[hi] = rec;
127
128         return 0;
129 }
130
131
132 static int xdl_prepare_ctx(mmfile_t *mf, long narec, xpparam_t const *xpp,
133                            xdlclassifier_t *cf, xdfile_t *xdf) {
134         unsigned int hbits;
135         long i, nrec, hsize, bsize;
136         unsigned long hav;
137         char const *blk, *cur, *top, *prev;
138         xrecord_t *crec;
139         xrecord_t **recs, **rrecs;
140         xrecord_t **rhash;
141         unsigned long *ha;
142         char *rchg;
143         long *rindex;
144
145         if (xdl_cha_init(&xdf->rcha, sizeof(xrecord_t), narec / 4 + 1) < 0) {
146
147                 return -1;
148         }
149         if (!(recs = (xrecord_t **) xdl_malloc(narec * sizeof(xrecord_t *)))) {
150
151                 xdl_cha_free(&xdf->rcha);
152                 return -1;
153         }
154
155         hbits = xdl_hashbits((unsigned int) narec);
156         hsize = 1 << hbits;
157         if (!(rhash = (xrecord_t **) xdl_malloc(hsize * sizeof(xrecord_t *)))) {
158
159                 xdl_free(recs);
160                 xdl_cha_free(&xdf->rcha);
161                 return -1;
162         }
163         for (i = 0; i < hsize; i++)
164                 rhash[i] = NULL;
165
166         nrec = 0;
167         if ((cur = blk = xdl_mmfile_first(mf, &bsize)) != NULL) {
168                 for (top = blk + bsize;;) {
169                         if (cur >= top) {
170                                 if (!(cur = blk = xdl_mmfile_next(mf, &bsize)))
171                                         break;
172                                 top = blk + bsize;
173                         }
174                         prev = cur;
175                         hav = xdl_hash_record(&cur, top);
176                         if (nrec >= narec) {
177                                 narec *= 2;
178                                 if (!(rrecs = (xrecord_t **) xdl_realloc(recs, narec * sizeof(xrecord_t *)))) {
179
180                                         xdl_free(rhash);
181                                         xdl_free(recs);
182                                         xdl_cha_free(&xdf->rcha);
183                                         return -1;
184                                 }
185                                 recs = rrecs;
186                         }
187                         if (!(crec = xdl_cha_alloc(&xdf->rcha))) {
188
189                                 xdl_free(rhash);
190                                 xdl_free(recs);
191                                 xdl_cha_free(&xdf->rcha);
192                                 return -1;
193                         }
194                         crec->ptr = prev;
195                         crec->size = (long) (cur - prev);
196                         crec->ha = hav;
197                         recs[nrec++] = crec;
198
199                         if (xdl_classify_record(cf, rhash, hbits, crec) < 0) {
200
201                                 xdl_free(rhash);
202                                 xdl_free(recs);
203                                 xdl_cha_free(&xdf->rcha);
204                                 return -1;
205                         }
206                 }
207         }
208
209         if (!(rchg = (char *) xdl_malloc((nrec + 2) * sizeof(char)))) {
210
211                 xdl_free(rhash);
212                 xdl_free(recs);
213                 xdl_cha_free(&xdf->rcha);
214                 return -1;
215         }
216         memset(rchg, 0, (nrec + 2) * sizeof(char));
217
218         if (!(rindex = (long *) xdl_malloc((nrec + 1) * sizeof(long)))) {
219
220                 xdl_free(rchg);
221                 xdl_free(rhash);
222                 xdl_free(recs);
223                 xdl_cha_free(&xdf->rcha);
224                 return -1;
225         }
226         if (!(ha = (unsigned long *) xdl_malloc((nrec + 1) * sizeof(unsigned long)))) {
227
228                 xdl_free(rindex);
229                 xdl_free(rchg);
230                 xdl_free(rhash);
231                 xdl_free(recs);
232                 xdl_cha_free(&xdf->rcha);
233                 return -1;
234         }
235
236         xdf->nrec = nrec;
237         xdf->recs = recs;
238         xdf->hbits = hbits;
239         xdf->rhash = rhash;
240         xdf->rchg = rchg + 1;
241         xdf->rindex = rindex;
242         xdf->nreff = 0;
243         xdf->ha = ha;
244         xdf->dstart = 0;
245         xdf->dend = nrec - 1;
246
247         return 0;
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;
265         xdlclassifier_t cf;
266
267         enl1 = xdl_guess_lines(mf1) + 1;
268         enl2 = xdl_guess_lines(mf2) + 1;
269
270         if (xdl_init_classifier(&cf, enl1 + enl2 + 1) < 0) {
271
272                 return -1;
273         }
274
275         if (xdl_prepare_ctx(mf1, enl1, xpp, &cf, &xe->xdf1) < 0) {
276
277                 xdl_free_classifier(&cf);
278                 return -1;
279         }
280         if (xdl_prepare_ctx(mf2, enl2, xpp, &cf, &xe->xdf2) < 0) {
281
282                 xdl_free_ctx(&xe->xdf1);
283                 xdl_free_classifier(&cf);
284                 return -1;
285         }
286
287         xdl_free_classifier(&cf);
288
289         if (xdl_optimize_ctxs(&xe->xdf1, &xe->xdf2) < 0) {
290
291                 xdl_free_ctx(&xe->xdf2);
292                 xdl_free_ctx(&xe->xdf1);
293                 return -1;
294         }
295
296         return 0;
297 }
298
299
300 void xdl_free_env(xdfenv_t *xe) {
301
302         xdl_free_ctx(&xe->xdf2);
303         xdl_free_ctx(&xe->xdf1);
304 }
305
306
307 static int xdl_clean_mmatch(char const *dis, long i, long s, long e) {
308         long r, rdis, rpdis;
309
310         for (r = 1, rdis = 0, rpdis = 1; (i - r) >= s; r++) {
311                 if (!dis[i - r])
312                         rdis++;
313                 else if (dis[i - r] == 2)
314                         rpdis++;
315                 else
316                         break;
317         }
318         for (r = 1; (i + r) <= e; r++) {
319                 if (!dis[i + r])
320                         rdis++;
321                 else if (dis[i + r] == 2)
322                         rpdis++;
323                 else
324                         break;
325         }
326
327         return rpdis * XDL_KPDIS_RUN < (rpdis + rdis);
328 }
329
330
331 /*
332  * Try to reduce the problem complexity, discard records that have no
333  * matches on the other file. Also, lines that have multiple matches
334  * might be potentially discarded if they happear in a run of discardable.
335  */
336 static int xdl_cleanup_records(xdfile_t *xdf1, xdfile_t *xdf2) {
337         long i, rhi, nreff;
338         unsigned long hav;
339         xrecord_t **recs;
340         xrecord_t *rec;
341         char *dis, *dis1, *dis2;
342
343         if (!(dis = (char *) xdl_malloc((xdf1->nrec + xdf2->nrec + 2) * sizeof(char)))) {
344
345                 return -1;
346         }
347         memset(dis, 0, (xdf1->nrec + xdf2->nrec + 2) * sizeof(char));
348         dis1 = dis;
349         dis2 = dis1 + xdf1->nrec + 1;
350
351         for (i = xdf1->dstart, recs = &xdf1->recs[xdf1->dstart]; i <= xdf1->dend; i++, recs++) {
352                 hav = (*recs)->ha;
353                 rhi = (long) XDL_HASHLONG(hav, xdf2->hbits);
354                 for (rec = xdf2->rhash[rhi]; rec; rec = rec->next)
355                         if (rec->ha == hav && ++dis1[i] == 2)
356                                 break;
357         }
358
359         for (i = xdf2->dstart, recs = &xdf2->recs[xdf2->dstart]; i <= xdf2->dend; i++, recs++) {
360                 hav = (*recs)->ha;
361                 rhi = (long) XDL_HASHLONG(hav, xdf1->hbits);
362                 for (rec = xdf1->rhash[rhi]; rec; rec = rec->next)
363                         if (rec->ha == hav && ++dis2[i] == 2)
364                                 break;
365         }
366
367         for (nreff = 0, i = xdf1->dstart, recs = &xdf1->recs[xdf1->dstart];
368              i <= xdf1->dend; i++, recs++) {
369                 if (dis1[i] == 1 ||
370                     (dis1[i] == 2 && !xdl_clean_mmatch(dis1, i, xdf1->dstart, xdf1->dend))) {
371                         xdf1->rindex[nreff] = i;
372                         xdf1->ha[nreff] = (*recs)->ha;
373                         nreff++;
374                 } else
375                         xdf1->rchg[i] = 1;
376         }
377         xdf1->nreff = nreff;
378
379         for (nreff = 0, i = xdf2->dstart, recs = &xdf2->recs[xdf2->dstart];
380              i <= xdf2->dend; i++, recs++) {
381                 if (dis2[i] == 1 ||
382                     (dis2[i] == 2 && !xdl_clean_mmatch(dis2, i, xdf2->dstart, xdf2->dend))) {
383                         xdf2->rindex[nreff] = i;
384                         xdf2->ha[nreff] = (*recs)->ha;
385                         nreff++;
386                 } else
387                         xdf2->rchg[i] = 1;
388         }
389         xdf2->nreff = nreff;
390
391         xdl_free(dis);
392
393         return 0;
394 }
395
396
397 /*
398  * Early trim initial and terminal matching records.
399  */
400 static int xdl_trim_ends(xdfile_t *xdf1, xdfile_t *xdf2) {
401         long i, lim;
402         xrecord_t **recs1, **recs2;
403
404         recs1 = xdf1->recs;
405         recs2 = xdf2->recs;
406         for (i = 0, lim = XDL_MIN(xdf1->nrec, xdf2->nrec); i < lim;
407              i++, recs1++, recs2++)
408                 if ((*recs1)->ha != (*recs2)->ha)
409                         break;
410
411         xdf1->dstart = xdf2->dstart = i;
412
413         recs1 = xdf1->recs + xdf1->nrec - 1;
414         recs2 = xdf2->recs + xdf2->nrec - 1;
415         for (lim -= i, i = 0; i < lim; i++, recs1--, recs2--)
416                 if ((*recs1)->ha != (*recs2)->ha)
417                         break;
418
419         xdf1->dend = xdf1->nrec - i - 1;
420         xdf2->dend = xdf2->nrec - i - 1;
421
422         return 0;
423 }
424
425
426 static int xdl_optimize_ctxs(xdfile_t *xdf1, xdfile_t *xdf2) {
427
428         if (xdl_trim_ends(xdf1, xdf2) < 0 ||
429             xdl_cleanup_records(xdf1, xdf2) < 0) {
430
431                 return -1;
432         }
433
434         return 0;
435 }
436