| /* | |
| * LibXDiff by Davide Libenzi ( File Differential Library ) | |
| * Copyright (C) 2003 Davide Libenzi | |
| * | |
| * This library is free software; you can redistribute it and/or | |
| * modify it under the terms of the GNU Lesser General Public | |
| * License as published by the Free Software Foundation; either | |
| * version 2.1 of the License, or (at your option) any later version. | |
| * | |
| * This library is distributed in the hope that it will be useful, | |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| * Lesser General Public License for more details. | |
| * | |
| * You should have received a copy of the GNU Lesser General Public | |
| * License along with this library; if not, write to the Free Software | |
| * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
| * | |
| * Davide Libenzi <davidel@xmailserver.org> | |
| * | |
| */ | |
| #include "xinclude.h" | |
| #define XDL_KPDIS_RUN 4 | |
| #define XDL_MAX_EQLIMIT 1024 | |
| #define XDL_SIMSCAN_WINDOW 100 | |
| typedef struct s_xdlclass { | |
| struct s_xdlclass *next; | |
| unsigned long ha; | |
| char const *line; | |
| long size; | |
| long idx; | |
| } xdlclass_t; | |
| typedef struct s_xdlclassifier { | |
| unsigned int hbits; | |
| long hsize; | |
| xdlclass_t **rchash; | |
| chastore_t ncha; | |
| long count; | |
| long flags; | |
| } xdlclassifier_t; | |
| static int xdl_init_classifier(xdlclassifier_t *cf, long size, long flags); | |
| static void xdl_free_classifier(xdlclassifier_t *cf); | |
| static int xdl_classify_record(xdlclassifier_t *cf, xrecord_t **rhash, unsigned int hbits, | |
| xrecord_t *rec); | |
| static int xdl_prepare_ctx(mmfile_t *mf, long narec, xpparam_t const *xpp, | |
| xdlclassifier_t *cf, xdfile_t *xdf); | |
| static void xdl_free_ctx(xdfile_t *xdf); | |
| static int xdl_clean_mmatch(char const *dis, long i, long s, long e); | |
| static int xdl_cleanup_records(xdfile_t *xdf1, xdfile_t *xdf2); | |
| static int xdl_trim_ends(xdfile_t *xdf1, xdfile_t *xdf2); | |
| static int xdl_optimize_ctxs(xdfile_t *xdf1, xdfile_t *xdf2); | |
| static int xdl_init_classifier(xdlclassifier_t *cf, long size, long flags) { | |
| long i; | |
| cf->flags = flags; | |
| cf->hbits = xdl_hashbits((unsigned int) size); | |
| cf->hsize = 1 << cf->hbits; | |
| if (xdl_cha_init(&cf->ncha, sizeof(xdlclass_t), size / 4 + 1) < 0) { | |
| return -1; | |
| } | |
| if (!(cf->rchash = (xdlclass_t **) xdl_malloc(cf->hsize * sizeof(xdlclass_t *)))) { | |
| xdl_cha_free(&cf->ncha); | |
| return -1; | |
| } | |
| for (i = 0; i < cf->hsize; i++) | |
| cf->rchash[i] = NULL; | |
| cf->count = 0; | |
| return 0; | |
| } | |
| static void xdl_free_classifier(xdlclassifier_t *cf) { | |
| xdl_free(cf->rchash); | |
| xdl_cha_free(&cf->ncha); | |
| } | |
| static int xdl_classify_record(xdlclassifier_t *cf, xrecord_t **rhash, unsigned int hbits, | |
| xrecord_t *rec) { | |
| long hi; | |
| char const *line; | |
| xdlclass_t *rcrec; | |
| line = rec->ptr; | |
| hi = (long) XDL_HASHLONG(rec->ha, cf->hbits); | |
| for (rcrec = cf->rchash[hi]; rcrec; rcrec = rcrec->next) | |
| if (rcrec->ha == rec->ha && | |
| xdl_recmatch(rcrec->line, rcrec->size, | |
| rec->ptr, rec->size, cf->flags)) | |
| break; | |
| if (!rcrec) { | |
| if (!(rcrec = xdl_cha_alloc(&cf->ncha))) { | |
| return -1; | |
| } | |
| rcrec->idx = cf->count++; | |
| rcrec->line = line; | |
| rcrec->size = rec->size; | |
| rcrec->ha = rec->ha; | |
| rcrec->next = cf->rchash[hi]; | |
| cf->rchash[hi] = rcrec; | |
| } | |
| rec->ha = (unsigned long) rcrec->idx; | |
| hi = (long) XDL_HASHLONG(rec->ha, hbits); | |
| rec->next = rhash[hi]; | |
| rhash[hi] = rec; | |
| return 0; | |
| } | |
| static int xdl_prepare_ctx(mmfile_t *mf, long narec, xpparam_t const *xpp, | |
| xdlclassifier_t *cf, xdfile_t *xdf) { | |
| unsigned int hbits; | |
| long i, nrec, hsize, bsize; | |
| unsigned long hav; | |
| char const *blk, *cur, *top, *prev; | |
| xrecord_t *crec; | |
| xrecord_t **recs, **rrecs; | |
| xrecord_t **rhash; | |
| unsigned long *ha; | |
| char *rchg; | |
| long *rindex; | |
| if (xdl_cha_init(&xdf->rcha, sizeof(xrecord_t), narec / 4 + 1) < 0) { | |
| return -1; | |
| } | |
| if (!(recs = (xrecord_t **) xdl_malloc(narec * sizeof(xrecord_t *)))) { | |
| xdl_cha_free(&xdf->rcha); | |
| return -1; | |
| } | |
| hbits = xdl_hashbits((unsigned int) narec); | |
| hsize = 1 << hbits; | |
| if (!(rhash = (xrecord_t **) xdl_malloc(hsize * sizeof(xrecord_t *)))) { | |
| xdl_free(recs); | |
| xdl_cha_free(&xdf->rcha); | |
| return -1; | |
| } | |
| for (i = 0; i < hsize; i++) | |
| rhash[i] = NULL; | |
| nrec = 0; | |
| if ((cur = blk = xdl_mmfile_first(mf, &bsize)) != NULL) { | |
| for (top = blk + bsize;;) { | |
| if (cur >= top) { | |
| if (!(cur = blk = xdl_mmfile_next(mf, &bsize))) | |
| break; | |
| top = blk + bsize; | |
| } | |
| prev = cur; | |
| hav = xdl_hash_record(&cur, top, xpp->flags); | |
| if (nrec >= narec) { | |
| narec *= 2; | |
| if (!(rrecs = (xrecord_t **) xdl_realloc(recs, narec * sizeof(xrecord_t *)))) { | |
| xdl_free(rhash); | |
| xdl_free(recs); | |
| xdl_cha_free(&xdf->rcha); | |
| return -1; | |
| } | |
| recs = rrecs; | |
| } | |
| if (!(crec = xdl_cha_alloc(&xdf->rcha))) { | |
| xdl_free(rhash); | |
| xdl_free(recs); | |
| xdl_cha_free(&xdf->rcha); | |
| return -1; | |
| } | |
| crec->ptr = prev; | |
| crec->size = (long) (cur - prev); | |
| crec->ha = hav; | |
| recs[nrec++] = crec; | |
| if (xdl_classify_record(cf, rhash, hbits, crec) < 0) { | |
| xdl_free(rhash); | |
| xdl_free(recs); | |
| xdl_cha_free(&xdf->rcha); | |
| return -1; | |
| } | |
| } | |
| } | |
| if (!(rchg = (char *) xdl_malloc((nrec + 2) * sizeof(char)))) { | |
| xdl_free(rhash); | |
| xdl_free(recs); | |
| xdl_cha_free(&xdf->rcha); | |
| return -1; | |
| } | |
| memset(rchg, 0, (nrec + 2) * sizeof(char)); | |
| if (!(rindex = (long *) xdl_malloc((nrec + 1) * sizeof(long)))) { | |
| xdl_free(rchg); | |
| xdl_free(rhash); | |
| xdl_free(recs); | |
| xdl_cha_free(&xdf->rcha); | |
| return -1; | |
| } | |
| if (!(ha = (unsigned long *) xdl_malloc((nrec + 1) * sizeof(unsigned long)))) { | |
| xdl_free(rindex); | |
| xdl_free(rchg); | |
| xdl_free(rhash); | |
| xdl_free(recs); | |
| xdl_cha_free(&xdf->rcha); | |
| return -1; | |
| } | |
| xdf->nrec = nrec; | |
| xdf->recs = recs; | |
| xdf->hbits = hbits; | |
| xdf->rhash = rhash; | |
| xdf->rchg = rchg + 1; | |
| xdf->rindex = rindex; | |
| xdf->nreff = 0; | |
| xdf->ha = ha; | |
| xdf->dstart = 0; | |
| xdf->dend = nrec - 1; | |
| return 0; | |
| } | |
| static void xdl_free_ctx(xdfile_t *xdf) { | |
| xdl_free(xdf->rhash); | |
| xdl_free(xdf->rindex); | |
| xdl_free(xdf->rchg - 1); | |
| xdl_free(xdf->ha); | |
| xdl_free(xdf->recs); | |
| xdl_cha_free(&xdf->rcha); | |
| } | |
| int xdl_prepare_env(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp, | |
| xdfenv_t *xe) { | |
| long enl1, enl2; | |
| xdlclassifier_t cf; | |
| enl1 = xdl_guess_lines(mf1) + 1; | |
| enl2 = xdl_guess_lines(mf2) + 1; | |
| if (xdl_init_classifier(&cf, enl1 + enl2 + 1, xpp->flags) < 0) { | |
| return -1; | |
| } | |
| if (xdl_prepare_ctx(mf1, enl1, xpp, &cf, &xe->xdf1) < 0) { | |
| xdl_free_classifier(&cf); | |
| return -1; | |
| } | |
| if (xdl_prepare_ctx(mf2, enl2, xpp, &cf, &xe->xdf2) < 0) { | |
| xdl_free_ctx(&xe->xdf1); | |
| xdl_free_classifier(&cf); | |
| return -1; | |
| } | |
| xdl_free_classifier(&cf); | |
| if (!(xpp->flags & XDF_PATIENCE_DIFF) && | |
| xdl_optimize_ctxs(&xe->xdf1, &xe->xdf2) < 0) { | |
| xdl_free_ctx(&xe->xdf2); | |
| xdl_free_ctx(&xe->xdf1); | |
| return -1; | |
| } | |
| return 0; | |
| } | |
| void xdl_free_env(xdfenv_t *xe) { | |
| xdl_free_ctx(&xe->xdf2); | |
| xdl_free_ctx(&xe->xdf1); | |
| } | |
| static int xdl_clean_mmatch(char const *dis, long i, long s, long e) { | |
| long r, rdis0, rpdis0, rdis1, rpdis1; | |
| /* | |
| * Limits the window the is examined during the similar-lines | |
| * scan. The loops below stops when dis[i - r] == 1 (line that | |
| * has no match), but there are corner cases where the loop | |
| * proceed all the way to the extremities by causing huge | |
| * performance penalties in case of big files. | |
| */ | |
| if (i - s > XDL_SIMSCAN_WINDOW) | |
| s = i - XDL_SIMSCAN_WINDOW; | |
| if (e - i > XDL_SIMSCAN_WINDOW) | |
| e = i + XDL_SIMSCAN_WINDOW; | |
| /* | |
| * Scans the lines before 'i' to find a run of lines that either | |
| * have no match (dis[j] == 0) or have multiple matches (dis[j] > 1). | |
| * Note that we always call this function with dis[i] > 1, so the | |
| * current line (i) is already a multimatch line. | |
| */ | |
| for (r = 1, rdis0 = 0, rpdis0 = 1; (i - r) >= s; r++) { | |
| if (!dis[i - r]) | |
| rdis0++; | |
| else if (dis[i - r] == 2) | |
| rpdis0++; | |
| else | |
| break; | |
| } | |
| /* | |
| * If the run before the line 'i' found only multimatch lines, we | |
| * return 0 and hence we don't make the current line (i) discarded. | |
| * We want to discard multimatch lines only when they appear in the | |
| * middle of runs with nomatch lines (dis[j] == 0). | |
| */ | |
| if (rdis0 == 0) | |
| return 0; | |
| for (r = 1, rdis1 = 0, rpdis1 = 1; (i + r) <= e; r++) { | |
| if (!dis[i + r]) | |
| rdis1++; | |
| else if (dis[i + r] == 2) | |
| rpdis1++; | |
| else | |
| break; | |
| } | |
| /* | |
| * If the run after the line 'i' found only multimatch lines, we | |
| * return 0 and hence we don't make the current line (i) discarded. | |
| */ | |
| if (rdis1 == 0) | |
| return 0; | |
| rdis1 += rdis0; | |
| rpdis1 += rpdis0; | |
| return rpdis1 * XDL_KPDIS_RUN < (rpdis1 + rdis1); | |
| } | |
| /* | |
| * Try to reduce the problem complexity, discard records that have no | |
| * matches on the other file. Also, lines that have multiple matches | |
| * might be potentially discarded if they happear in a run of discardable. | |
| */ | |
| static int xdl_cleanup_records(xdfile_t *xdf1, xdfile_t *xdf2) { | |
| long i, nm, rhi, nreff, mlim; | |
| unsigned long hav; | |
| xrecord_t **recs; | |
| xrecord_t *rec; | |
| char *dis, *dis1, *dis2; | |
| if (!(dis = (char *) xdl_malloc(xdf1->nrec + xdf2->nrec + 2))) { | |
| return -1; | |
| } | |
| memset(dis, 0, xdf1->nrec + xdf2->nrec + 2); | |
| dis1 = dis; | |
| dis2 = dis1 + xdf1->nrec + 1; | |
| if ((mlim = xdl_bogosqrt(xdf1->nrec)) > XDL_MAX_EQLIMIT) | |
| mlim = XDL_MAX_EQLIMIT; | |
| for (i = xdf1->dstart, recs = &xdf1->recs[xdf1->dstart]; i <= xdf1->dend; i++, recs++) { | |
| hav = (*recs)->ha; | |
| rhi = (long) XDL_HASHLONG(hav, xdf2->hbits); | |
| for (nm = 0, rec = xdf2->rhash[rhi]; rec; rec = rec->next) | |
| if (rec->ha == hav && ++nm == mlim) | |
| break; | |
| dis1[i] = (nm == 0) ? 0: (nm >= mlim) ? 2: 1; | |
| } | |
| if ((mlim = xdl_bogosqrt(xdf2->nrec)) > XDL_MAX_EQLIMIT) | |
| mlim = XDL_MAX_EQLIMIT; | |
| for (i = xdf2->dstart, recs = &xdf2->recs[xdf2->dstart]; i <= xdf2->dend; i++, recs++) { | |
| hav = (*recs)->ha; | |
| rhi = (long) XDL_HASHLONG(hav, xdf1->hbits); | |
| for (nm = 0, rec = xdf1->rhash[rhi]; rec; rec = rec->next) | |
| if (rec->ha == hav && ++nm == mlim) | |
| break; | |
| dis2[i] = (nm == 0) ? 0: (nm >= mlim) ? 2: 1; | |
| } | |
| for (nreff = 0, i = xdf1->dstart, recs = &xdf1->recs[xdf1->dstart]; | |
| i <= xdf1->dend; i++, recs++) { | |
| if (dis1[i] == 1 || | |
| (dis1[i] == 2 && !xdl_clean_mmatch(dis1, i, xdf1->dstart, xdf1->dend))) { | |
| xdf1->rindex[nreff] = i; | |
| xdf1->ha[nreff] = (*recs)->ha; | |
| nreff++; | |
| } else | |
| xdf1->rchg[i] = 1; | |
| } | |
| xdf1->nreff = nreff; | |
| for (nreff = 0, i = xdf2->dstart, recs = &xdf2->recs[xdf2->dstart]; | |
| i <= xdf2->dend; i++, recs++) { | |
| if (dis2[i] == 1 || | |
| (dis2[i] == 2 && !xdl_clean_mmatch(dis2, i, xdf2->dstart, xdf2->dend))) { | |
| xdf2->rindex[nreff] = i; | |
| xdf2->ha[nreff] = (*recs)->ha; | |
| nreff++; | |
| } else | |
| xdf2->rchg[i] = 1; | |
| } | |
| xdf2->nreff = nreff; | |
| xdl_free(dis); | |
| return 0; | |
| } | |
| /* | |
| * Early trim initial and terminal matching records. | |
| */ | |
| static int xdl_trim_ends(xdfile_t *xdf1, xdfile_t *xdf2) { | |
| long i, lim; | |
| xrecord_t **recs1, **recs2; | |
| recs1 = xdf1->recs; | |
| recs2 = xdf2->recs; | |
| for (i = 0, lim = XDL_MIN(xdf1->nrec, xdf2->nrec); i < lim; | |
| i++, recs1++, recs2++) | |
| if ((*recs1)->ha != (*recs2)->ha) | |
| break; | |
| xdf1->dstart = xdf2->dstart = i; | |
| recs1 = xdf1->recs + xdf1->nrec - 1; | |
| recs2 = xdf2->recs + xdf2->nrec - 1; | |
| for (lim -= i, i = 0; i < lim; i++, recs1--, recs2--) | |
| if ((*recs1)->ha != (*recs2)->ha) | |
| break; | |
| xdf1->dend = xdf1->nrec - i - 1; | |
| xdf2->dend = xdf2->nrec - i - 1; | |
| return 0; | |
| } | |
| static int xdl_optimize_ctxs(xdfile_t *xdf1, xdfile_t *xdf2) { | |
| if (xdl_trim_ends(xdf1, xdf2) < 0 || | |
| xdl_cleanup_records(xdf1, xdf2) < 0) { | |
| return -1; | |
| } | |
| return 0; | |
| } |