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![Junio C Hamano](/assets/img/avatar_default.png)
* rs/diff-cleanup-records-fix: diff: resurrect XDF_NEED_MINIMAL with --minimal Revert removal of multi-match discard heuristic in 27af01
484 lines
12 KiB
C
484 lines
12 KiB
C
/*
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* LibXDiff by Davide Libenzi ( File Differential Library )
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* Copyright (C) 2003 Davide Libenzi
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* Davide Libenzi <davidel@xmailserver.org>
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*
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*/
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#include "xinclude.h"
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#define XDL_KPDIS_RUN 4
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#define XDL_MAX_EQLIMIT 1024
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#define XDL_SIMSCAN_WINDOW 100
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#define XDL_GUESS_NLINES1 256
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#define XDL_GUESS_NLINES2 20
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typedef struct s_xdlclass {
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struct s_xdlclass *next;
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unsigned long ha;
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char const *line;
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long size;
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long idx;
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long len1, len2;
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} xdlclass_t;
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typedef struct s_xdlclassifier {
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unsigned int hbits;
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long hsize;
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xdlclass_t **rchash;
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chastore_t ncha;
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xdlclass_t **rcrecs;
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long alloc;
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long count;
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long flags;
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} xdlclassifier_t;
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static int xdl_init_classifier(xdlclassifier_t *cf, long size, long flags);
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static void xdl_free_classifier(xdlclassifier_t *cf);
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static int xdl_classify_record(unsigned int pass, xdlclassifier_t *cf, xrecord_t **rhash,
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unsigned int hbits, xrecord_t *rec);
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static int xdl_prepare_ctx(unsigned int pass, mmfile_t *mf, long narec, xpparam_t const *xpp,
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xdlclassifier_t *cf, xdfile_t *xdf);
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static void xdl_free_ctx(xdfile_t *xdf);
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static int xdl_clean_mmatch(char const *dis, long i, long s, long e);
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static int xdl_cleanup_records(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xdf2);
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static int xdl_trim_ends(xdfile_t *xdf1, xdfile_t *xdf2);
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static int xdl_optimize_ctxs(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xdf2);
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static int xdl_init_classifier(xdlclassifier_t *cf, long size, long flags) {
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cf->flags = flags;
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cf->hbits = xdl_hashbits((unsigned int) size);
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cf->hsize = 1 << cf->hbits;
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if (xdl_cha_init(&cf->ncha, sizeof(xdlclass_t), size / 4 + 1) < 0) {
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return -1;
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}
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if (!(cf->rchash = (xdlclass_t **) xdl_malloc(cf->hsize * sizeof(xdlclass_t *)))) {
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xdl_cha_free(&cf->ncha);
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return -1;
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}
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memset(cf->rchash, 0, cf->hsize * sizeof(xdlclass_t *));
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cf->alloc = size;
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if (!(cf->rcrecs = (xdlclass_t **) xdl_malloc(cf->alloc * sizeof(xdlclass_t *)))) {
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xdl_free(cf->rchash);
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xdl_cha_free(&cf->ncha);
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return -1;
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}
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cf->count = 0;
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return 0;
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}
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static void xdl_free_classifier(xdlclassifier_t *cf) {
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xdl_free(cf->rcrecs);
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xdl_free(cf->rchash);
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xdl_cha_free(&cf->ncha);
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}
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static int xdl_classify_record(unsigned int pass, xdlclassifier_t *cf, xrecord_t **rhash,
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unsigned int hbits, xrecord_t *rec) {
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long hi;
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char const *line;
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xdlclass_t *rcrec;
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xdlclass_t **rcrecs;
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line = rec->ptr;
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hi = (long) XDL_HASHLONG(rec->ha, cf->hbits);
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for (rcrec = cf->rchash[hi]; rcrec; rcrec = rcrec->next)
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if (rcrec->ha == rec->ha &&
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xdl_recmatch(rcrec->line, rcrec->size,
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rec->ptr, rec->size, cf->flags))
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break;
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if (!rcrec) {
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if (!(rcrec = xdl_cha_alloc(&cf->ncha))) {
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return -1;
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}
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rcrec->idx = cf->count++;
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if (cf->count > cf->alloc) {
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cf->alloc *= 2;
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if (!(rcrecs = (xdlclass_t **) xdl_realloc(cf->rcrecs, cf->alloc * sizeof(xdlclass_t *)))) {
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return -1;
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}
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cf->rcrecs = rcrecs;
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}
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cf->rcrecs[rcrec->idx] = rcrec;
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rcrec->line = line;
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rcrec->size = rec->size;
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rcrec->ha = rec->ha;
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rcrec->len1 = rcrec->len2 = 0;
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rcrec->next = cf->rchash[hi];
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cf->rchash[hi] = rcrec;
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}
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(pass == 1) ? rcrec->len1++ : rcrec->len2++;
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rec->ha = (unsigned long) rcrec->idx;
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hi = (long) XDL_HASHLONG(rec->ha, hbits);
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rec->next = rhash[hi];
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rhash[hi] = rec;
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return 0;
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}
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static int xdl_prepare_ctx(unsigned int pass, mmfile_t *mf, long narec, xpparam_t const *xpp,
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xdlclassifier_t *cf, xdfile_t *xdf) {
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unsigned int hbits;
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long nrec, hsize, bsize;
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unsigned long hav;
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char const *blk, *cur, *top, *prev;
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xrecord_t *crec;
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xrecord_t **recs, **rrecs;
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xrecord_t **rhash;
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unsigned long *ha;
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char *rchg;
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long *rindex;
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ha = NULL;
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rindex = NULL;
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rchg = NULL;
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rhash = NULL;
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recs = NULL;
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if (xdl_cha_init(&xdf->rcha, sizeof(xrecord_t), narec / 4 + 1) < 0)
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goto abort;
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if (!(recs = (xrecord_t **) xdl_malloc(narec * sizeof(xrecord_t *))))
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goto abort;
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if (xpp->flags & XDF_HISTOGRAM_DIFF)
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hbits = hsize = 0;
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else {
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hbits = xdl_hashbits((unsigned int) narec);
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hsize = 1 << hbits;
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if (!(rhash = (xrecord_t **) xdl_malloc(hsize * sizeof(xrecord_t *))))
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goto abort;
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memset(rhash, 0, hsize * sizeof(xrecord_t *));
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}
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nrec = 0;
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if ((cur = blk = xdl_mmfile_first(mf, &bsize)) != NULL) {
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for (top = blk + bsize; cur < top; ) {
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prev = cur;
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hav = xdl_hash_record(&cur, top, xpp->flags);
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if (nrec >= narec) {
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narec *= 2;
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if (!(rrecs = (xrecord_t **) xdl_realloc(recs, narec * sizeof(xrecord_t *))))
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goto abort;
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recs = rrecs;
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}
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if (!(crec = xdl_cha_alloc(&xdf->rcha)))
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goto abort;
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crec->ptr = prev;
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crec->size = (long) (cur - prev);
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crec->ha = hav;
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recs[nrec++] = crec;
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if (!(xpp->flags & XDF_HISTOGRAM_DIFF) &&
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xdl_classify_record(pass, cf, rhash, hbits, crec) < 0)
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goto abort;
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}
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}
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if (!(rchg = (char *) xdl_malloc((nrec + 2) * sizeof(char))))
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goto abort;
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memset(rchg, 0, (nrec + 2) * sizeof(char));
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if (!(rindex = (long *) xdl_malloc((nrec + 1) * sizeof(long))))
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goto abort;
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if (!(ha = (unsigned long *) xdl_malloc((nrec + 1) * sizeof(unsigned long))))
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goto abort;
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xdf->nrec = nrec;
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xdf->recs = recs;
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xdf->hbits = hbits;
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xdf->rhash = rhash;
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xdf->rchg = rchg + 1;
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xdf->rindex = rindex;
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xdf->nreff = 0;
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xdf->ha = ha;
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xdf->dstart = 0;
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xdf->dend = nrec - 1;
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return 0;
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abort:
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xdl_free(ha);
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xdl_free(rindex);
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xdl_free(rchg);
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xdl_free(rhash);
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xdl_free(recs);
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xdl_cha_free(&xdf->rcha);
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return -1;
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}
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static void xdl_free_ctx(xdfile_t *xdf) {
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xdl_free(xdf->rhash);
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xdl_free(xdf->rindex);
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xdl_free(xdf->rchg - 1);
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xdl_free(xdf->ha);
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xdl_free(xdf->recs);
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xdl_cha_free(&xdf->rcha);
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}
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int xdl_prepare_env(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
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xdfenv_t *xe) {
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long enl1, enl2, sample;
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xdlclassifier_t cf;
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memset(&cf, 0, sizeof(cf));
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/*
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* For histogram diff, we can afford a smaller sample size and
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* thus a poorer estimate of the number of lines, as the hash
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* table (rhash) won't be filled up/grown. The number of lines
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* (nrecs) will be updated correctly anyway by
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* xdl_prepare_ctx().
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*/
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sample = xpp->flags & XDF_HISTOGRAM_DIFF ? XDL_GUESS_NLINES2 : XDL_GUESS_NLINES1;
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enl1 = xdl_guess_lines(mf1, sample) + 1;
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enl2 = xdl_guess_lines(mf2, sample) + 1;
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if (!(xpp->flags & XDF_HISTOGRAM_DIFF) &&
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xdl_init_classifier(&cf, enl1 + enl2 + 1, xpp->flags) < 0) {
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return -1;
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}
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if (xdl_prepare_ctx(1, mf1, enl1, xpp, &cf, &xe->xdf1) < 0) {
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xdl_free_classifier(&cf);
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return -1;
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}
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if (xdl_prepare_ctx(2, mf2, enl2, xpp, &cf, &xe->xdf2) < 0) {
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xdl_free_ctx(&xe->xdf1);
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xdl_free_classifier(&cf);
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return -1;
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}
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if (!(xpp->flags & XDF_PATIENCE_DIFF) &&
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!(xpp->flags & XDF_HISTOGRAM_DIFF) &&
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xdl_optimize_ctxs(&cf, &xe->xdf1, &xe->xdf2) < 0) {
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xdl_free_ctx(&xe->xdf2);
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xdl_free_ctx(&xe->xdf1);
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return -1;
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}
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if (!(xpp->flags & XDF_HISTOGRAM_DIFF))
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xdl_free_classifier(&cf);
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return 0;
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}
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void xdl_free_env(xdfenv_t *xe) {
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xdl_free_ctx(&xe->xdf2);
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xdl_free_ctx(&xe->xdf1);
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}
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static int xdl_clean_mmatch(char const *dis, long i, long s, long e) {
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long r, rdis0, rpdis0, rdis1, rpdis1;
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/*
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* Limits the window the is examined during the similar-lines
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* scan. The loops below stops when dis[i - r] == 1 (line that
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* has no match), but there are corner cases where the loop
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* proceed all the way to the extremities by causing huge
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* performance penalties in case of big files.
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*/
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if (i - s > XDL_SIMSCAN_WINDOW)
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s = i - XDL_SIMSCAN_WINDOW;
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if (e - i > XDL_SIMSCAN_WINDOW)
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e = i + XDL_SIMSCAN_WINDOW;
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/*
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* Scans the lines before 'i' to find a run of lines that either
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* have no match (dis[j] == 0) or have multiple matches (dis[j] > 1).
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* Note that we always call this function with dis[i] > 1, so the
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* current line (i) is already a multimatch line.
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*/
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for (r = 1, rdis0 = 0, rpdis0 = 1; (i - r) >= s; r++) {
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if (!dis[i - r])
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rdis0++;
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else if (dis[i - r] == 2)
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rpdis0++;
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else
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break;
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}
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/*
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* If the run before the line 'i' found only multimatch lines, we
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* return 0 and hence we don't make the current line (i) discarded.
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* We want to discard multimatch lines only when they appear in the
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* middle of runs with nomatch lines (dis[j] == 0).
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*/
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if (rdis0 == 0)
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return 0;
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for (r = 1, rdis1 = 0, rpdis1 = 1; (i + r) <= e; r++) {
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if (!dis[i + r])
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rdis1++;
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else if (dis[i + r] == 2)
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rpdis1++;
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else
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break;
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}
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/*
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* If the run after the line 'i' found only multimatch lines, we
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* return 0 and hence we don't make the current line (i) discarded.
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*/
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if (rdis1 == 0)
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return 0;
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rdis1 += rdis0;
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rpdis1 += rpdis0;
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return rpdis1 * XDL_KPDIS_RUN < (rpdis1 + rdis1);
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}
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/*
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* Try to reduce the problem complexity, discard records that have no
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* matches on the other file. Also, lines that have multiple matches
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* might be potentially discarded if they happear in a run of discardable.
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*/
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static int xdl_cleanup_records(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xdf2) {
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long i, nm, nreff, mlim;
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xrecord_t **recs;
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xdlclass_t *rcrec;
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char *dis, *dis1, *dis2;
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if (!(dis = (char *) xdl_malloc(xdf1->nrec + xdf2->nrec + 2))) {
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return -1;
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}
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memset(dis, 0, xdf1->nrec + xdf2->nrec + 2);
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dis1 = dis;
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dis2 = dis1 + xdf1->nrec + 1;
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if ((mlim = xdl_bogosqrt(xdf1->nrec)) > XDL_MAX_EQLIMIT)
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mlim = XDL_MAX_EQLIMIT;
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for (i = xdf1->dstart, recs = &xdf1->recs[xdf1->dstart]; i <= xdf1->dend; i++, recs++) {
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rcrec = cf->rcrecs[(*recs)->ha];
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nm = rcrec ? rcrec->len2 : 0;
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dis1[i] = (nm == 0) ? 0: (nm >= mlim) ? 2: 1;
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}
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if ((mlim = xdl_bogosqrt(xdf2->nrec)) > XDL_MAX_EQLIMIT)
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mlim = XDL_MAX_EQLIMIT;
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for (i = xdf2->dstart, recs = &xdf2->recs[xdf2->dstart]; i <= xdf2->dend; i++, recs++) {
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rcrec = cf->rcrecs[(*recs)->ha];
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nm = rcrec ? rcrec->len1 : 0;
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dis2[i] = (nm == 0) ? 0: (nm >= mlim) ? 2: 1;
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}
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for (nreff = 0, i = xdf1->dstart, recs = &xdf1->recs[xdf1->dstart];
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i <= xdf1->dend; i++, recs++) {
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if (dis1[i] == 1 ||
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(dis1[i] == 2 && !xdl_clean_mmatch(dis1, i, xdf1->dstart, xdf1->dend))) {
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xdf1->rindex[nreff] = i;
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xdf1->ha[nreff] = (*recs)->ha;
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nreff++;
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} else
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xdf1->rchg[i] = 1;
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}
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xdf1->nreff = nreff;
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for (nreff = 0, i = xdf2->dstart, recs = &xdf2->recs[xdf2->dstart];
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i <= xdf2->dend; i++, recs++) {
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if (dis2[i] == 1 ||
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(dis2[i] == 2 && !xdl_clean_mmatch(dis2, i, xdf2->dstart, xdf2->dend))) {
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xdf2->rindex[nreff] = i;
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xdf2->ha[nreff] = (*recs)->ha;
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nreff++;
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} else
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xdf2->rchg[i] = 1;
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}
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xdf2->nreff = nreff;
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xdl_free(dis);
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return 0;
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}
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/*
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* Early trim initial and terminal matching records.
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*/
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static int xdl_trim_ends(xdfile_t *xdf1, xdfile_t *xdf2) {
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long i, lim;
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xrecord_t **recs1, **recs2;
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recs1 = xdf1->recs;
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recs2 = xdf2->recs;
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for (i = 0, lim = XDL_MIN(xdf1->nrec, xdf2->nrec); i < lim;
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i++, recs1++, recs2++)
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if ((*recs1)->ha != (*recs2)->ha)
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break;
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xdf1->dstart = xdf2->dstart = i;
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recs1 = xdf1->recs + xdf1->nrec - 1;
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recs2 = xdf2->recs + xdf2->nrec - 1;
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for (lim -= i, i = 0; i < lim; i++, recs1--, recs2--)
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if ((*recs1)->ha != (*recs2)->ha)
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break;
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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;
|
|
}
|