/* * 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 #define XDL_GUESS_NLINES1 256 #define XDL_GUESS_NLINES2 20 typedef struct s_xdlclass { struct s_xdlclass *next; unsigned long ha; char const *line; long size; long idx; long len1, len2; } xdlclass_t; typedef struct s_xdlclassifier { unsigned int hbits; long hsize; xdlclass_t **rchash; chastore_t ncha; xdlclass_t **rcrecs; long alloc; 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(unsigned int pass, xdlclassifier_t *cf, xrecord_t **rhash, unsigned int hbits, xrecord_t *rec); static int xdl_prepare_ctx(unsigned int pass, 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(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xdf2); static int xdl_trim_ends(xdfile_t *xdf1, xdfile_t *xdf2); static int xdl_optimize_ctxs(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xdf2); static int xdl_init_classifier(xdlclassifier_t *cf, long size, long flags) { 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; } memset(cf->rchash, 0, cf->hsize * sizeof(xdlclass_t *)); cf->alloc = size; if (!(cf->rcrecs = (xdlclass_t **) xdl_malloc(cf->alloc * sizeof(xdlclass_t *)))) { xdl_free(cf->rchash); xdl_cha_free(&cf->ncha); return -1; } cf->count = 0; return 0; } static void xdl_free_classifier(xdlclassifier_t *cf) { xdl_free(cf->rcrecs); xdl_free(cf->rchash); xdl_cha_free(&cf->ncha); } static int xdl_classify_record(unsigned int pass, xdlclassifier_t *cf, xrecord_t **rhash, unsigned int hbits, xrecord_t *rec) { long hi; char const *line; xdlclass_t *rcrec; xdlclass_t **rcrecs; 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++; if (cf->count > cf->alloc) { cf->alloc *= 2; if (!(rcrecs = (xdlclass_t **) xdl_realloc(cf->rcrecs, cf->alloc * sizeof(xdlclass_t *)))) { return -1; } cf->rcrecs = rcrecs; } cf->rcrecs[rcrec->idx] = rcrec; rcrec->line = line; rcrec->size = rec->size; rcrec->ha = rec->ha; rcrec->len1 = rcrec->len2 = 0; rcrec->next = cf->rchash[hi]; cf->rchash[hi] = rcrec; } (pass == 1) ? rcrec->len1++ : rcrec->len2++; 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(unsigned int pass, mmfile_t *mf, long narec, xpparam_t const *xpp, xdlclassifier_t *cf, xdfile_t *xdf) { unsigned int hbits; long 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; ha = NULL; rindex = NULL; rchg = NULL; rhash = NULL; recs = NULL; if (xdl_cha_init(&xdf->rcha, sizeof(xrecord_t), narec / 4 + 1) < 0) goto abort; if (!(recs = (xrecord_t **) xdl_malloc(narec * sizeof(xrecord_t *)))) goto abort; if (XDF_DIFF_ALG(xpp->flags) == XDF_HISTOGRAM_DIFF) hbits = hsize = 0; else { hbits = xdl_hashbits((unsigned int) narec); hsize = 1 << hbits; if (!(rhash = (xrecord_t **) xdl_malloc(hsize * sizeof(xrecord_t *)))) goto abort; memset(rhash, 0, hsize * sizeof(xrecord_t *)); } nrec = 0; if ((cur = blk = xdl_mmfile_first(mf, &bsize)) != NULL) { for (top = blk + bsize; cur < top; ) { 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 *)))) goto abort; recs = rrecs; } if (!(crec = xdl_cha_alloc(&xdf->rcha))) goto abort; crec->ptr = prev; crec->size = (long) (cur - prev); crec->ha = hav; recs[nrec++] = crec; if ((XDF_DIFF_ALG(xpp->flags) != XDF_HISTOGRAM_DIFF) && xdl_classify_record(pass, cf, rhash, hbits, crec) < 0) goto abort; } } if (!(rchg = (char *) xdl_malloc((nrec + 2) * sizeof(char)))) goto abort; memset(rchg, 0, (nrec + 2) * sizeof(char)); if (!(rindex = (long *) xdl_malloc((nrec + 1) * sizeof(long)))) goto abort; if (!(ha = (unsigned long *) xdl_malloc((nrec + 1) * sizeof(unsigned long)))) goto abort; 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; abort: xdl_free(ha); xdl_free(rindex); xdl_free(rchg); xdl_free(rhash); xdl_free(recs); xdl_cha_free(&xdf->rcha); return -1; } 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, sample; xdlclassifier_t cf; memset(&cf, 0, sizeof(cf)); /* * For histogram diff, we can afford a smaller sample size and * thus a poorer estimate of the number of lines, as the hash * table (rhash) won't be filled up/grown. The number of lines * (nrecs) will be updated correctly anyway by * xdl_prepare_ctx(). */ sample = (XDF_DIFF_ALG(xpp->flags) == XDF_HISTOGRAM_DIFF ? XDL_GUESS_NLINES2 : XDL_GUESS_NLINES1); enl1 = xdl_guess_lines(mf1, sample) + 1; enl2 = xdl_guess_lines(mf2, sample) + 1; if (XDF_DIFF_ALG(xpp->flags) != XDF_HISTOGRAM_DIFF && xdl_init_classifier(&cf, enl1 + enl2 + 1, xpp->flags) < 0) return -1; if (xdl_prepare_ctx(1, mf1, enl1, xpp, &cf, &xe->xdf1) < 0) { xdl_free_classifier(&cf); return -1; } if (xdl_prepare_ctx(2, mf2, enl2, xpp, &cf, &xe->xdf2) < 0) { xdl_free_ctx(&xe->xdf1); xdl_free_classifier(&cf); return -1; } if ((XDF_DIFF_ALG(xpp->flags) != XDF_PATIENCE_DIFF) && (XDF_DIFF_ALG(xpp->flags) != XDF_HISTOGRAM_DIFF) && xdl_optimize_ctxs(&cf, &xe->xdf1, &xe->xdf2) < 0) { xdl_free_ctx(&xe->xdf2); xdl_free_ctx(&xe->xdf1); return -1; } if (!(xpp->flags & XDF_HISTOGRAM_DIFF)) xdl_free_classifier(&cf); 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(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xdf2) { long i, nm, nreff, mlim; xrecord_t **recs; xdlclass_t *rcrec; 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++) { rcrec = cf->rcrecs[(*recs)->ha]; nm = rcrec ? rcrec->len2 : 0; 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++) { rcrec = cf->rcrecs[(*recs)->ha]; nm = rcrec ? rcrec->len1 : 0; 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(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xdf2) { if (xdl_trim_ends(xdf1, xdf2) < 0 || xdl_cleanup_records(cf, xdf1, xdf2) < 0) { return -1; } return 0; }