Andrew's git - gitweb.git/blob

   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
  31typedef 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
  39typedef 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
  50static int xdl_init_classifier(xdlclassifier_t *cf, long size);
  51static void xdl_free_classifier(xdlclassifier_t *cf);
  52static int xdl_classify_record(xdlclassifier_t *cf, xrecord_t **rhash, unsigned int hbits,
  53                               xrecord_t *rec);
  54static int xdl_prepare_ctx(mmfile_t *mf, long narec, xpparam_t const *xpp,
  55                           xdlclassifier_t *cf, xdfile_t *xdf);
  56static void xdl_free_ctx(xdfile_t *xdf);
  57static int xdl_clean_mmatch(char const *dis, long i, long s, long e);
  58static int xdl_cleanup_records(xdfile_t *xdf1, xdfile_t *xdf2);
  59static int xdl_trim_ends(xdfile_t *xdf1, xdfile_t *xdf2);
  60static int xdl_optimize_ctxs(xdfile_t *xdf1, xdfile_t *xdf2);
  61
  62
  63
  64
  65static 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
  89static void xdl_free_classifier(xdlclassifier_t *cf) {
  90
  91        xdl_free(cf->rchash);
  92        xdl_cha_free(&cf->ncha);
  93}
  94
  95
  96static 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
 132static 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
 251static 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
 262int 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
 300void xdl_free_env(xdfenv_t *xe) {
 301
 302        xdl_free_ctx(&xe->xdf2);
 303        xdl_free_ctx(&xe->xdf1);
 304}
 305
 306
 307static 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 */
 336static 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 */
 400static 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
 426static 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