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#define XDL_MAX_EQLIMIT 1024
  29
  30
  31
  32typedef struct s_xdlclass {
  33        struct s_xdlclass *next;
  34        unsigned long ha;
  35        char const *line;
  36        long size;
  37        long idx;
  38} xdlclass_t;
  39
  40typedef struct s_xdlclassifier {
  41        unsigned int hbits;
  42        long hsize;
  43        xdlclass_t **rchash;
  44        chastore_t ncha;
  45        long count;
  46} xdlclassifier_t;
  47
  48
  49
  50
  51static int xdl_init_classifier(xdlclassifier_t *cf, long size);
  52static void xdl_free_classifier(xdlclassifier_t *cf);
  53static int xdl_classify_record(xdlclassifier_t *cf, xrecord_t **rhash, unsigned int hbits,
  54                               xrecord_t *rec);
  55static int xdl_prepare_ctx(mmfile_t *mf, long narec, xpparam_t const *xpp,
  56                           xdlclassifier_t *cf, xdfile_t *xdf);
  57static void xdl_free_ctx(xdfile_t *xdf);
  58static int xdl_clean_mmatch(char const *dis, long i, long s, long e);
  59static int xdl_cleanup_records(xdfile_t *xdf1, xdfile_t *xdf2);
  60static int xdl_trim_ends(xdfile_t *xdf1, xdfile_t *xdf2);
  61static int xdl_optimize_ctxs(xdfile_t *xdf1, xdfile_t *xdf2);
  62
  63
  64
  65
  66static int xdl_init_classifier(xdlclassifier_t *cf, long size) {
  67        long i;
  68
  69        cf->hbits = xdl_hashbits((unsigned int) size);
  70        cf->hsize = 1 << cf->hbits;
  71
  72        if (xdl_cha_init(&cf->ncha, sizeof(xdlclass_t), size / 4 + 1) < 0) {
  73
  74                return -1;
  75        }
  76        if (!(cf->rchash = (xdlclass_t **) xdl_malloc(cf->hsize * sizeof(xdlclass_t *)))) {
  77
  78                xdl_cha_free(&cf->ncha);
  79                return -1;
  80        }
  81        for (i = 0; i < cf->hsize; i++)
  82                cf->rchash[i] = NULL;
  83
  84        cf->count = 0;
  85
  86        return 0;
  87}
  88
  89
  90static void xdl_free_classifier(xdlclassifier_t *cf) {
  91
  92        xdl_free(cf->rchash);
  93        xdl_cha_free(&cf->ncha);
  94}
  95
  96
  97static int xdl_classify_record(xdlclassifier_t *cf, xrecord_t **rhash, unsigned int hbits,
  98                               xrecord_t *rec) {
  99        long hi;
 100        char const *line;
 101        xdlclass_t *rcrec;
 102
 103        line = rec->ptr;
 104        hi = (long) XDL_HASHLONG(rec->ha, cf->hbits);
 105        for (rcrec = cf->rchash[hi]; rcrec; rcrec = rcrec->next)
 106                if (rcrec->ha == rec->ha && rcrec->size == rec->size &&
 107                    !memcmp(line, rcrec->line, rec->size))
 108                        break;
 109
 110        if (!rcrec) {
 111                if (!(rcrec = xdl_cha_alloc(&cf->ncha))) {
 112
 113                        return -1;
 114                }
 115                rcrec->idx = cf->count++;
 116                rcrec->line = line;
 117                rcrec->size = rec->size;
 118                rcrec->ha = rec->ha;
 119                rcrec->next = cf->rchash[hi];
 120                cf->rchash[hi] = rcrec;
 121        }
 122
 123        rec->ha = (unsigned long) rcrec->idx;
 124
 125        hi = (long) XDL_HASHLONG(rec->ha, hbits);
 126        rec->next = rhash[hi];
 127        rhash[hi] = rec;
 128
 129        return 0;
 130}
 131
 132
 133static int xdl_prepare_ctx(mmfile_t *mf, long narec, xpparam_t const *xpp,
 134                           xdlclassifier_t *cf, xdfile_t *xdf) {
 135        unsigned int hbits;
 136        long i, nrec, hsize, bsize;
 137        unsigned long hav;
 138        char const *blk, *cur, *top, *prev;
 139        xrecord_t *crec;
 140        xrecord_t **recs, **rrecs;
 141        xrecord_t **rhash;
 142        unsigned long *ha;
 143        char *rchg;
 144        long *rindex;
 145
 146        if (xdl_cha_init(&xdf->rcha, sizeof(xrecord_t), narec / 4 + 1) < 0) {
 147
 148                return -1;
 149        }
 150        if (!(recs = (xrecord_t **) xdl_malloc(narec * sizeof(xrecord_t *)))) {
 151
 152                xdl_cha_free(&xdf->rcha);
 153                return -1;
 154        }
 155
 156        hbits = xdl_hashbits((unsigned int) narec);
 157        hsize = 1 << hbits;
 158        if (!(rhash = (xrecord_t **) xdl_malloc(hsize * sizeof(xrecord_t *)))) {
 159
 160                xdl_free(recs);
 161                xdl_cha_free(&xdf->rcha);
 162                return -1;
 163        }
 164        for (i = 0; i < hsize; i++)
 165                rhash[i] = NULL;
 166
 167        nrec = 0;
 168        if ((cur = blk = xdl_mmfile_first(mf, &bsize)) != NULL) {
 169                for (top = blk + bsize;;) {
 170                        if (cur >= top) {
 171                                if (!(cur = blk = xdl_mmfile_next(mf, &bsize)))
 172                                        break;
 173                                top = blk + bsize;
 174                        }
 175                        prev = cur;
 176                        hav = xdl_hash_record(&cur, top);
 177                        if (nrec >= narec) {
 178                                narec *= 2;
 179                                if (!(rrecs = (xrecord_t **) xdl_realloc(recs, narec * sizeof(xrecord_t *)))) {
 180
 181                                        xdl_free(rhash);
 182                                        xdl_free(recs);
 183                                        xdl_cha_free(&xdf->rcha);
 184                                        return -1;
 185                                }
 186                                recs = rrecs;
 187                        }
 188                        if (!(crec = xdl_cha_alloc(&xdf->rcha))) {
 189
 190                                xdl_free(rhash);
 191                                xdl_free(recs);
 192                                xdl_cha_free(&xdf->rcha);
 193                                return -1;
 194                        }
 195                        crec->ptr = prev;
 196                        crec->size = (long) (cur - prev);
 197                        crec->ha = hav;
 198                        recs[nrec++] = crec;
 199
 200                        if (xdl_classify_record(cf, rhash, hbits, crec) < 0) {
 201
 202                                xdl_free(rhash);
 203                                xdl_free(recs);
 204                                xdl_cha_free(&xdf->rcha);
 205                                return -1;
 206                        }
 207                }
 208        }
 209
 210        if (!(rchg = (char *) xdl_malloc((nrec + 2) * sizeof(char)))) {
 211
 212                xdl_free(rhash);
 213                xdl_free(recs);
 214                xdl_cha_free(&xdf->rcha);
 215                return -1;
 216        }
 217        memset(rchg, 0, (nrec + 2) * sizeof(char));
 218
 219        if (!(rindex = (long *) xdl_malloc((nrec + 1) * sizeof(long)))) {
 220
 221                xdl_free(rchg);
 222                xdl_free(rhash);
 223                xdl_free(recs);
 224                xdl_cha_free(&xdf->rcha);
 225                return -1;
 226        }
 227        if (!(ha = (unsigned long *) xdl_malloc((nrec + 1) * sizeof(unsigned long)))) {
 228
 229                xdl_free(rindex);
 230                xdl_free(rchg);
 231                xdl_free(rhash);
 232                xdl_free(recs);
 233                xdl_cha_free(&xdf->rcha);
 234                return -1;
 235        }
 236
 237        xdf->nrec = nrec;
 238        xdf->recs = recs;
 239        xdf->hbits = hbits;
 240        xdf->rhash = rhash;
 241        xdf->rchg = rchg + 1;
 242        xdf->rindex = rindex;
 243        xdf->nreff = 0;
 244        xdf->ha = ha;
 245        xdf->dstart = 0;
 246        xdf->dend = nrec - 1;
 247
 248        return 0;
 249}
 250
 251
 252static void xdl_free_ctx(xdfile_t *xdf) {
 253
 254        xdl_free(xdf->rhash);
 255        xdl_free(xdf->rindex);
 256        xdl_free(xdf->rchg - 1);
 257        xdl_free(xdf->ha);
 258        xdl_free(xdf->recs);
 259        xdl_cha_free(&xdf->rcha);
 260}
 261
 262
 263int xdl_prepare_env(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
 264                    xdfenv_t *xe) {
 265        long enl1, enl2;
 266        xdlclassifier_t cf;
 267
 268        enl1 = xdl_guess_lines(mf1) + 1;
 269        enl2 = xdl_guess_lines(mf2) + 1;
 270
 271        if (xdl_init_classifier(&cf, enl1 + enl2 + 1) < 0) {
 272
 273                return -1;
 274        }
 275
 276        if (xdl_prepare_ctx(mf1, enl1, xpp, &cf, &xe->xdf1) < 0) {
 277
 278                xdl_free_classifier(&cf);
 279                return -1;
 280        }
 281        if (xdl_prepare_ctx(mf2, enl2, xpp, &cf, &xe->xdf2) < 0) {
 282
 283                xdl_free_ctx(&xe->xdf1);
 284                xdl_free_classifier(&cf);
 285                return -1;
 286        }
 287
 288        xdl_free_classifier(&cf);
 289
 290        if (xdl_optimize_ctxs(&xe->xdf1, &xe->xdf2) < 0) {
 291
 292                xdl_free_ctx(&xe->xdf2);
 293                xdl_free_ctx(&xe->xdf1);
 294                return -1;
 295        }
 296
 297        return 0;
 298}
 299
 300
 301void xdl_free_env(xdfenv_t *xe) {
 302
 303        xdl_free_ctx(&xe->xdf2);
 304        xdl_free_ctx(&xe->xdf1);
 305}
 306
 307
 308static int xdl_clean_mmatch(char const *dis, long i, long s, long e) {
 309        long r, rdis0, rpdis0, rdis1, rpdis1;
 310
 311        /*
 312         * Scans the lines before 'i' to find a run of lines that either
 313         * have no match (dis[j] == 0) or have multiple matches (dis[j] > 1).
 314         * Note that we always call this function with dis[i] > 1, so the
 315         * current line (i) is already a multimatch line.
 316         */
 317        for (r = 1, rdis0 = 0, rpdis0 = 1; (i - r) >= s; r++) {
 318                if (!dis[i - r])
 319                        rdis0++;
 320                else if (dis[i - r] == 2)
 321                        rpdis0++;
 322                else
 323                        break;
 324        }
 325        /*
 326         * If the run before the line 'i' found only multimatch lines, we
 327         * return 0 and hence we don't make the current line (i) discarded.
 328         * We want to discard multimatch lines only when they appear in the
 329         * middle of runs with nomatch lines (dis[j] == 0).
 330         */
 331        if (rdis0 == 0)
 332                return 0;
 333        for (r = 1, rdis1 = 0, rpdis1 = 1; (i + r) <= e; r++) {
 334                if (!dis[i + r])
 335                        rdis1++;
 336                else if (dis[i + r] == 2)
 337                        rpdis1++;
 338                else
 339                        break;
 340        }
 341        /*
 342         * If the run after the line 'i' found only multimatch lines, we
 343         * return 0 and hence we don't make the current line (i) discarded.
 344         */
 345        if (rdis1 == 0)
 346                return 0;
 347        rdis1 += rdis0;
 348        rpdis1 += rpdis0;
 349
 350        return rpdis1 * XDL_KPDIS_RUN < (rpdis1 + rdis1);
 351}
 352
 353
 354/*
 355 * Try to reduce the problem complexity, discard records that have no
 356 * matches on the other file. Also, lines that have multiple matches
 357 * might be potentially discarded if they happear in a run of discardable.
 358 */
 359static int xdl_cleanup_records(xdfile_t *xdf1, xdfile_t *xdf2) {
 360        long i, nm, rhi, nreff, mlim;
 361        unsigned long hav;
 362        xrecord_t **recs;
 363        xrecord_t *rec;
 364        char *dis, *dis1, *dis2;
 365
 366        if (!(dis = (char *) xdl_malloc(xdf1->nrec + xdf2->nrec + 2))) {
 367
 368                return -1;
 369        }
 370        memset(dis, 0, xdf1->nrec + xdf2->nrec + 2);
 371        dis1 = dis;
 372        dis2 = dis1 + xdf1->nrec + 1;
 373
 374        if ((mlim = xdl_bogosqrt(xdf1->nrec)) > XDL_MAX_EQLIMIT)
 375                mlim = XDL_MAX_EQLIMIT;
 376        for (i = xdf1->dstart, recs = &xdf1->recs[xdf1->dstart]; i <= xdf1->dend; i++, recs++) {
 377                hav = (*recs)->ha;
 378                rhi = (long) XDL_HASHLONG(hav, xdf2->hbits);
 379                for (nm = 0, rec = xdf2->rhash[rhi]; rec; rec = rec->next)
 380                        if (rec->ha == hav && ++nm == mlim)
 381                                break;
 382                dis1[i] = (nm == 0) ? 0: (nm >= mlim) ? 2: 1;
 383        }
 384
 385        if ((mlim = xdl_bogosqrt(xdf2->nrec)) > XDL_MAX_EQLIMIT)
 386                mlim = XDL_MAX_EQLIMIT;
 387        for (i = xdf2->dstart, recs = &xdf2->recs[xdf2->dstart]; i <= xdf2->dend; i++, recs++) {
 388                hav = (*recs)->ha;
 389                rhi = (long) XDL_HASHLONG(hav, xdf1->hbits);
 390                for (nm = 0, rec = xdf1->rhash[rhi]; rec; rec = rec->next)
 391                        if (rec->ha == hav && ++nm == mlim)
 392                                break;
 393                dis2[i] = (nm == 0) ? 0: (nm >= mlim) ? 2: 1;
 394        }
 395
 396        for (nreff = 0, i = xdf1->dstart, recs = &xdf1->recs[xdf1->dstart];
 397             i <= xdf1->dend; i++, recs++) {
 398                if (dis1[i] == 1 ||
 399                    (dis1[i] == 2 && !xdl_clean_mmatch(dis1, i, xdf1->dstart, xdf1->dend))) {
 400                        xdf1->rindex[nreff] = i;
 401                        xdf1->ha[nreff] = (*recs)->ha;
 402                        nreff++;
 403                } else
 404                        xdf1->rchg[i] = 1;
 405        }
 406        xdf1->nreff = nreff;
 407
 408        for (nreff = 0, i = xdf2->dstart, recs = &xdf2->recs[xdf2->dstart];
 409             i <= xdf2->dend; i++, recs++) {
 410                if (dis2[i] == 1 ||
 411                    (dis2[i] == 2 && !xdl_clean_mmatch(dis2, i, xdf2->dstart, xdf2->dend))) {
 412                        xdf2->rindex[nreff] = i;
 413                        xdf2->ha[nreff] = (*recs)->ha;
 414                        nreff++;
 415                } else
 416                        xdf2->rchg[i] = 1;
 417        }
 418        xdf2->nreff = nreff;
 419
 420        xdl_free(dis);
 421
 422        return 0;
 423}
 424
 425
 426/*
 427 * Early trim initial and terminal matching records.
 428 */
 429static int xdl_trim_ends(xdfile_t *xdf1, xdfile_t *xdf2) {
 430        long i, lim;
 431        xrecord_t **recs1, **recs2;
 432
 433        recs1 = xdf1->recs;
 434        recs2 = xdf2->recs;
 435        for (i = 0, lim = XDL_MIN(xdf1->nrec, xdf2->nrec); i < lim;
 436             i++, recs1++, recs2++)
 437                if ((*recs1)->ha != (*recs2)->ha)
 438                        break;
 439
 440        xdf1->dstart = xdf2->dstart = i;
 441
 442        recs1 = xdf1->recs + xdf1->nrec - 1;
 443        recs2 = xdf2->recs + xdf2->nrec - 1;
 444        for (lim -= i, i = 0; i < lim; i++, recs1--, recs2--)
 445                if ((*recs1)->ha != (*recs2)->ha)
 446                        break;
 447
 448        xdf1->dend = xdf1->nrec - i - 1;
 449        xdf2->dend = xdf2->nrec - i - 1;
 450
 451        return 0;
 452}
 453
 454
 455static int xdl_optimize_ctxs(xdfile_t *xdf1, xdfile_t *xdf2) {
 456
 457        if (xdl_trim_ends(xdf1, xdf2) < 0 ||
 458            xdl_cleanup_records(xdf1, xdf2) < 0) {
 459
 460                return -1;
 461        }
 462
 463        return 0;
 464}
 465