[thirdparty/git.git] / xdiff / xprepare.c

/*
 *  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


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;
} xdlclassifier_t;


static int xdl_init_classifier(xdlclassifier_t *cf, long size);
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 i;

	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 && rcrec->size == rec->size &&
		    !memcmp(line, rcrec->line, rec->size))
			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);
			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) < 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 (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;

	/*
	 * 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;
}
Commit	Line	Data
3443546f LT	1	/*
	2	* LibXDiff by Davide Libenzi ( File Differential Library )
	3	* Copyright (C) 2003 Davide Libenzi
	4	*
	5	* This library is free software; you can redistribute it and/or
	6	* modify it under the terms of the GNU Lesser General Public
	7	* License as published by the Free Software Foundation; either
	8	* version 2.1 of the License, or (at your option) any later version.
	9	*
	10	* This library is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	13	* Lesser General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU Lesser General Public
	16	* License along with this library; if not, write to the Free Software
	17	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	18	*
	19	* Davide Libenzi <davidel@xmailserver.org>
	20	*
	21	*/
	22
	23	#include "xinclude.h"
	24
	25
	26
	27	#define XDL_KPDIS_RUN 4
ca557aff	28	#define XDL_MAX_EQLIMIT 1024
3443546f LT	29
	30
	31
	32	typedef struct s_xdlclass {
	33	struct s_xdlclass *next;
	34	unsigned long ha;
	35	char const *line;
	36	long size;
	37	long idx;
	38	} xdlclass_t;
	39
	40	typedef struct s_xdlclassifier {
	41	unsigned int hbits;
	42	long hsize;
	43	xdlclass_t **rchash;
	44	chastore_t ncha;
	45	long count;
	46	} xdlclassifier_t;
	47
	48
	49
	50
	51	static int xdl_init_classifier(xdlclassifier_t *cf, long size);
	52	static void xdl_free_classifier(xdlclassifier_t *cf);
	53	static int xdl_classify_record(xdlclassifier_t cf, xrecord_t *rhash, unsigned int hbits,
	54	xrecord_t *rec);
	55	static int xdl_prepare_ctx(mmfile_t mf, long narec, xpparam_t const xpp,
	56	xdlclassifier_t cf, xdfile_t xdf);
	57	static void xdl_free_ctx(xdfile_t *xdf);
	58	static int xdl_clean_mmatch(char const *dis, long i, long s, long e);
	59	static int xdl_cleanup_records(xdfile_t xdf1, xdfile_t xdf2);
	60	static int xdl_trim_ends(xdfile_t xdf1, xdfile_t xdf2);
	61	static int xdl_optimize_ctxs(xdfile_t xdf1, xdfile_t xdf2);
	62
	63
	64
	65
	66	static int xdl_init_classifier(xdlclassifier_t *cf, long size) {
	67	long i;
	68
	69	cf->hbits = xdl_hashbits((unsigned int) size);
	70	cf->hsize = 1 << cf->hbits;
	71
	72	if (xdl_cha_init(&cf->ncha, sizeof(xdlclass_t), size / 4 + 1) < 0) {
	73
	74	return -1;
	75	}
	76	if (!(cf->rchash = (xdlclass_t *) xdl_malloc(cf->hsize sizeof(xdlclass_t *)))) {
	77
	78	xdl_cha_free(&cf->ncha);
	79	return -1;
	80	}
	81	for (i = 0; i < cf->hsize; i++)
	82	cf->rchash[i] = NULL;
	83
	84	cf->count = 0;
	85
	86	return 0;
	87	}
	88
	89
	90	static void xdl_free_classifier(xdlclassifier_t *cf) {
	91
	92	xdl_free(cf->rchash);
93	xdl_cha_free(&cf->ncha);
94	}
95
96
97	static int xdl_classify_record(xdlclassifier_t cf, xrecord_t *rhash, unsigned int hbits,
98	xrecord_t *rec) {
99	long hi;
100	char const *line;
101	xdlclass_t *rcrec;
102
103	line = rec->ptr;
104	hi = (long) XDL_HASHLONG(rec->ha, cf->hbits);
105	for (rcrec = cf->rchash[hi]; rcrec; rcrec = rcrec->next)
106	if (rcrec->ha == rec->ha && rcrec->size == rec->size &&
107	!memcmp(line, rcrec->line, rec->size))
108	break;
109
110	if (!rcrec) {
111	if (!(rcrec = xdl_cha_alloc(&cf->ncha))) {
112
113	return -1;
114	}
115	rcrec->idx = cf->count++;
116	rcrec->line = line;
117	rcrec->size = rec->size;
118	rcrec->ha = rec->ha;
119	rcrec->next = cf->rchash[hi];
120	cf->rchash[hi] = rcrec;
121	}
122
123	rec->ha = (unsigned long) rcrec->idx;
124
125	hi = (long) XDL_HASHLONG(rec->ha, hbits);
126	rec->next = rhash[hi];
127	rhash[hi] = rec;
128
129	return 0;
130	}
131
132
133	static int xdl_prepare_ctx(mmfile_t mf, long narec, xpparam_t const xpp,
134	xdlclassifier_t cf, xdfile_t xdf) {
135	unsigned int hbits;
136	long i, nrec, hsize, bsize;
137	unsigned long hav;
138	char const blk, cur, top, prev;
139	xrecord_t *crec;
140	xrecord_t recs, rrecs;
141	xrecord_t **rhash;
142	unsigned long *ha;
143	char *rchg;
144	long *rindex;
145
146	if (xdl_cha_init(&xdf->rcha, sizeof(xrecord_t), narec / 4 + 1) < 0) {
147
148	return -1;
149	}
150	if (!(recs = (xrecord_t *) xdl_malloc(narec sizeof(xrecord_t *)))) {
151
152	xdl_cha_free(&xdf->rcha);
153	return -1;
154	}
155
156	hbits = xdl_hashbits((unsigned int) narec);
157	hsize = 1 << hbits;
158	if (!(rhash = (xrecord_t *) xdl_malloc(hsize sizeof(xrecord_t *)))) {
159
160	xdl_free(recs);
161	xdl_cha_free(&xdf->rcha);
162	return -1;
163	}
164	for (i = 0; i < hsize; i++)
165	rhash[i] = NULL;
166
167	nrec = 0;
168	if ((cur = blk = xdl_mmfile_first(mf, &bsize)) != NULL) {
169	for (top = blk + bsize;;) {
170	if (cur >= top) {
171	if (!(cur = blk = xdl_mmfile_next(mf, &bsize)))
172	break;
173	top = blk + bsize;
174	}
175	prev = cur;
176	hav = xdl_hash_record(&cur, top);
177	if (nrec >= narec) {
178	narec *= 2;
179	if (!(rrecs = (xrecord_t *) xdl_realloc(recs, narec sizeof(xrecord_t *)))) {
180
181	xdl_free(rhash);
182	xdl_free(recs);
183	xdl_cha_free(&xdf->rcha);
184	return -1;
185	}
186	recs = rrecs;
187	}
188	if (!(crec = xdl_cha_alloc(&xdf->rcha))) {
189
190	xdl_free(rhash);
191	xdl_free(recs);
192	xdl_cha_free(&xdf->rcha);
193	return -1;
194	}
195	crec->ptr = prev;
196	crec->size = (long) (cur - prev);
197	crec->ha = hav;
198	recs[nrec++] = crec;
199
200	if (xdl_classify_record(cf, rhash, hbits, crec) < 0) {
201
202	xdl_free(rhash);
203	xdl_free(recs);
204	xdl_cha_free(&xdf->rcha);
205	return -1;
206	}
207	}
208	}
209
210	if (!(rchg = (char ) xdl_malloc((nrec + 2) sizeof(char)))) {
211
212	xdl_free(rhash);
213	xdl_free(recs);
214	xdl_cha_free(&xdf->rcha);
215	return -1;
216	}
217	memset(rchg, 0, (nrec + 2) * sizeof(char));
218
219	if (!(rindex = (long ) xdl_malloc((nrec + 1) sizeof(long)))) {
220
221	xdl_free(rchg);
222	xdl_free(rhash);
223	xdl_free(recs);
224	xdl_cha_free(&xdf->rcha);
225	return -1;
226	}
227	if (!(ha = (unsigned long ) xdl_malloc((nrec + 1) sizeof(unsigned long)))) {
228
229	xdl_free(rindex);
230	xdl_free(rchg);
231	xdl_free(rhash);
232	xdl_free(recs);
233	xdl_cha_free(&xdf->rcha);
234	return -1;
235	}
236
237	xdf->nrec = nrec;
238	xdf->recs = recs;
239	xdf->hbits = hbits;
240	xdf->rhash = rhash;
241	xdf->rchg = rchg + 1;
242	xdf->rindex = rindex;
243	xdf->nreff = 0;
244	xdf->ha = ha;
245	xdf->dstart = 0;
246	xdf->dend = nrec - 1;
247
248	return 0;
249	}
250
251
252	static void xdl_free_ctx(xdfile_t *xdf) {
253
254	xdl_free(xdf->rhash);
255	xdl_free(xdf->rindex);
256	xdl_free(xdf->rchg - 1);
257	xdl_free(xdf->ha);
258	xdl_free(xdf->recs);
259	xdl_cha_free(&xdf->rcha);
260	}
261
262
263	int xdl_prepare_env(mmfile_t mf1, mmfile_t mf2, xpparam_t const *xpp,
264	xdfenv_t *xe) {
265	long enl1, enl2;
266	xdlclassifier_t cf;
267
268	enl1 = xdl_guess_lines(mf1) + 1;
269	enl2 = xdl_guess_lines(mf2) + 1;
270
271	if (xdl_init_classifier(&cf, enl1 + enl2 + 1) < 0) {
272
273	return -1;
274	}
275
276	if (xdl_prepare_ctx(mf1, enl1, xpp, &cf, &xe->xdf1) < 0) {
277
278	xdl_free_classifier(&cf);
279	return -1;
280	}
281	if (xdl_prepare_ctx(mf2, enl2, xpp, &cf, &xe->xdf2) < 0) {
282
283	xdl_free_ctx(&xe->xdf1);
284	xdl_free_classifier(&cf);
285	return -1;
286	}
287
288	xdl_free_classifier(&cf);
289
290	if (xdl_optimize_ctxs(&xe->xdf1, &xe->xdf2) < 0) {
291
292	xdl_free_ctx(&xe->xdf2);
293	xdl_free_ctx(&xe->xdf1);
294	return -1;
295	}
296
297	return 0;
298	}
299
300
301	void xdl_free_env(xdfenv_t *xe) {
302
303	xdl_free_ctx(&xe->xdf2);
304	xdl_free_ctx(&xe->xdf1);
305	}
306
307
308	static int xdl_clean_mmatch(char const *dis, long i, long s, long e) {
ca557aff DL	309	long r, rdis0, rpdis0, rdis1, rpdis1;
	310
	311	/*
	312	* Scans the lines before 'i' to find a run of lines that either
	313	* have no match (dis[j] == 0) or have multiple matches (dis[j] > 1).
	314	* Note that we always call this function with dis[i] > 1, so the
	315	* current line (i) is already a multimatch line.
	316	*/
	317	for (r = 1, rdis0 = 0, rpdis0 = 1; (i - r) >= s; r++) {
3443546f	318	if (!dis[i - r])
ca557aff	319	rdis0++;
3443546f	320	else if (dis[i - r] == 2)
ca557aff	321	rpdis0++;
3443546f LT	322	else
	323	break;
	324	}
ca557aff DL	325	/*
	326	* If the run before the line 'i' found only multimatch lines, we
	327	* return 0 and hence we don't make the current line (i) discarded.
	328	* We want to discard multimatch lines only when they appear in the
	329	* middle of runs with nomatch lines (dis[j] == 0).
	330	*/
	331	if (rdis0 == 0)
	332	return 0;
	333	for (r = 1, rdis1 = 0, rpdis1 = 1; (i + r) <= e; r++) {
3443546f	334	if (!dis[i + r])
ca557aff	335	rdis1++;
3443546f	336	else if (dis[i + r] == 2)
ca557aff	337	rpdis1++;
3443546f LT	338	else
	339	break;
	340	}
ca557aff DL	341	/*
	342	* If the run after the line 'i' found only multimatch lines, we
	343	* return 0 and hence we don't make the current line (i) discarded.
	344	*/
	345	if (rdis1 == 0)
	346	return 0;
	347	rdis1 += rdis0;
	348	rpdis1 += rpdis0;
	349
	350	return rpdis1 * XDL_KPDIS_RUN < (rpdis1 + rdis1);
3443546f LT	351	}
	352
	353
	354	/*
	355	* Try to reduce the problem complexity, discard records that have no
	356	* matches on the other file. Also, lines that have multiple matches
	357	* might be potentially discarded if they happear in a run of discardable.
	358	*/
	359	static int xdl_cleanup_records(xdfile_t xdf1, xdfile_t xdf2) {
ca557aff	360	long i, nm, rhi, nreff, mlim;
3443546f LT	361	unsigned long hav;
	362	xrecord_t **recs;
	363	xrecord_t *rec;
	364	char dis, dis1, *dis2;
	365
ca557aff	366	if (!(dis = (char *) xdl_malloc(xdf1->nrec + xdf2->nrec + 2))) {
3443546f LT	367
	368	return -1;
	369	}
ca557aff	370	memset(dis, 0, xdf1->nrec + xdf2->nrec + 2);
3443546f LT	371	dis1 = dis;
	372	dis2 = dis1 + xdf1->nrec + 1;
	373
ca557aff DL	374	if ((mlim = xdl_bogosqrt(xdf1->nrec)) > XDL_MAX_EQLIMIT)
ca557aff DL	375	mlim = XDL_MAX_EQLIMIT;
3443546f LT	376	for (i = xdf1->dstart, recs = &xdf1->recs[xdf1->dstart]; i <= xdf1->dend; i++, recs++) {
	377	hav = (*recs)->ha;
	378	rhi = (long) XDL_HASHLONG(hav, xdf2->hbits);
ca557aff DL	379	for (nm = 0, rec = xdf2->rhash[rhi]; rec; rec = rec->next)
ca557aff DL	380	if (rec->ha == hav && ++nm == mlim)
3443546f	381	break;
ca557aff	382	dis1[i] = (nm == 0) ? 0: (nm >= mlim) ? 2: 1;
3443546f LT	383	}
3443546f LT	384
ca557aff DL	385	if ((mlim = xdl_bogosqrt(xdf2->nrec)) > XDL_MAX_EQLIMIT)
ca557aff DL	386	mlim = XDL_MAX_EQLIMIT;
3443546f LT	387	for (i = xdf2->dstart, recs = &xdf2->recs[xdf2->dstart]; i <= xdf2->dend; i++, recs++) {
	388	hav = (*recs)->ha;
	389	rhi = (long) XDL_HASHLONG(hav, xdf1->hbits);
ca557aff DL	390	for (nm = 0, rec = xdf1->rhash[rhi]; rec; rec = rec->next)
ca557aff DL	391	if (rec->ha == hav && ++nm == mlim)
3443546f	392	break;
ca557aff	393	dis2[i] = (nm == 0) ? 0: (nm >= mlim) ? 2: 1;
3443546f LT	394	}
	395
	396	for (nreff = 0, i = xdf1->dstart, recs = &xdf1->recs[xdf1->dstart];
	397	i <= xdf1->dend; i++, recs++) {
	398	if (dis1[i] == 1 \|\|
	399	(dis1[i] == 2 && !xdl_clean_mmatch(dis1, i, xdf1->dstart, xdf1->dend))) {
	400	xdf1->rindex[nreff] = i;
	401	xdf1->ha[nreff] = (*recs)->ha;
	402	nreff++;
	403	} else
	404	xdf1->rchg[i] = 1;
	405	}
	406	xdf1->nreff = nreff;
	407
	408	for (nreff = 0, i = xdf2->dstart, recs = &xdf2->recs[xdf2->dstart];
	409	i <= xdf2->dend; i++, recs++) {
	410	if (dis2[i] == 1 \|\|
	411	(dis2[i] == 2 && !xdl_clean_mmatch(dis2, i, xdf2->dstart, xdf2->dend))) {
	412	xdf2->rindex[nreff] = i;
	413	xdf2->ha[nreff] = (*recs)->ha;
	414	nreff++;
	415	} else
	416	xdf2->rchg[i] = 1;
	417	}
	418	xdf2->nreff = nreff;
	419
	420	xdl_free(dis);
	421
	422	return 0;
	423	}
	424
	425
	426	/*
	427	* Early trim initial and terminal matching records.
	428	*/
	429	static int xdl_trim_ends(xdfile_t xdf1, xdfile_t xdf2) {
	430	long i, lim;
	431	xrecord_t recs1, recs2;
	432
	433	recs1 = xdf1->recs;
	434	recs2 = xdf2->recs;
	435	for (i = 0, lim = XDL_MIN(xdf1->nrec, xdf2->nrec); i < lim;
	436	i++, recs1++, recs2++)
	437	if ((recs1)->ha != (recs2)->ha)
	438	break;
	439
	440	xdf1->dstart = xdf2->dstart = i;
	441
	442	recs1 = xdf1->recs + xdf1->nrec - 1;
	443	recs2 = xdf2->recs + xdf2->nrec - 1;
	444	for (lim -= i, i = 0; i < lim; i++, recs1--, recs2--)
	445	if ((recs1)->ha != (recs2)->ha)
	446	break;
	447
	448	xdf1->dend = xdf1->nrec - i - 1;
	449	xdf2->dend = xdf2->nrec - i - 1;
	450
	451	return 0;
	452	}
	453
	454
	455	static int xdl_optimize_ctxs(xdfile_t xdf1, xdfile_t xdf2) {
	456
	457	if (xdl_trim_ends(xdf1, xdf2) < 0 \|\|
458	xdl_cleanup_records(xdf1, xdf2) < 0) {
459
460	return -1;
461	}
462
463	return 0;
464	}
465