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-rw-r--r--src/xdiff/xprepare.c483
1 files changed, 483 insertions, 0 deletions
diff --git a/src/xdiff/xprepare.c b/src/xdiff/xprepare.c
new file mode 100644
index 0000000..abeb8fb
--- /dev/null
+++ b/src/xdiff/xprepare.c
@@ -0,0 +1,483 @@
+/*
+ * 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, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * 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);
+ xdl_free_classifier(&cf);
+ return -1;
+ }
+
+ if (XDF_DIFF_ALG(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;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-22 13:11:50 +0000