neovim

xprepare.c (12242B)

---

/*
*  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;
}