1 files changed, 157 insertions, 189 deletions

diff --git a/xdiff/xprepare.c b/xdiff/xprepare.c
index e1d4017b2d..192334f1b7 100644
--- a/xdiff/xprepare.c
+++ b/xdiff/xprepare.c
@@ -29,12 +29,13 @@
 #define XDL_GUESS_NLINES1 256
 #define XDL_GUESS_NLINES2 20
 
+#define DISCARD 0
+#define KEEP 1
+#define INVESTIGATE 2
 
 typedef struct s_xdlclass {
 	struct s_xdlclass *next;
-	unsigned long ha;
-	char const *line;
-	long size;
+	xrecord_t rec;
 	long idx;
 	long len1, len2;
 } xdlclass_t;
@@ -53,21 +54,6 @@ typedef struct s_xdlclassifier {
 
 
 
-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;
 
@@ -106,17 +92,14 @@ 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_classify_record(unsigned int pass, xdlclassifier_t *cf, 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 &&
-				xdl_recmatch(rcrec->line, rcrec->size,
+		if (rcrec->rec.ha == rec->ha &&
+				xdl_recmatch(rcrec->rec.ptr, rcrec->rec.size,
 					rec->ptr, rec->size, cf->flags))
 			break;
 
@@ -129,9 +112,7 @@ static int xdl_classify_record(unsigned int pass, xdlclassifier_t *cf, xrecord_t
 		if (XDL_ALLOC_GROW(cf->rcrecs, cf->count, cf->alloc))
 				return -1;
 		cf->rcrecs[rcrec->idx] = rcrec;
-		rcrec->line = line;
-		rcrec->size = rec->size;
-		rcrec->ha = rec->ha;
+		rcrec->rec = *rec;
 		rcrec->len1 = rcrec->len2 = 0;
 		rcrec->next = cf->rchash[hi];
 		cf->rchash[hi] = rcrec;
@@ -141,158 +122,70 @@ static int xdl_classify_record(unsigned int pass, xdlclassifier_t *cf, xrecord_t
 
 	rec->ha = (unsigned long) rcrec->idx;
 
-	hi = (long) XDL_HASHLONG(rec->ha, hbits);
-	rec->next = rhash[hi];
-	rhash[hi] = rec;
-
 	return 0;
 }
 
 
+static void xdl_free_ctx(xdfile_t *xdf)
+{
+	xdl_free(xdf->rindex);
+	xdl_free(xdf->changed - 1);
+	xdl_free(xdf->recs);
+}
+
+
 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;
+	long bsize;
 	unsigned long hav;
 	char const *blk, *cur, *top, *prev;
 	xrecord_t *crec;
-	xrecord_t **recs;
-	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 (!XDL_ALLOC_ARRAY(recs, narec))
-		goto abort;
 
-	hbits = xdl_hashbits((unsigned int) narec);
-	hsize = 1 << hbits;
-	if (!XDL_CALLOC_ARRAY(rhash, hsize))
+	xdf->rindex = NULL;
+	xdf->changed = NULL;
+	xdf->recs = NULL;
+
+	if (!XDL_ALLOC_ARRAY(xdf->recs, narec))
 		goto abort;
 
-	nrec = 0;
+	xdf->nrec = 0;
 	if ((cur = blk = xdl_mmfile_first(mf, &bsize))) {
 		for (top = blk + bsize; cur < top; ) {
 			prev = cur;
 			hav = xdl_hash_record(&cur, top, xpp->flags);
-			if (XDL_ALLOC_GROW(recs, nrec + 1, narec))
-				goto abort;
-			if (!(crec = xdl_cha_alloc(&xdf->rcha)))
+			if (XDL_ALLOC_GROW(xdf->recs, xdf->nrec + 1, narec))
 				goto abort;
+			crec = &xdf->recs[xdf->nrec++];
 			crec->ptr = prev;
 			crec->size = (long) (cur - prev);
 			crec->ha = hav;
-			recs[nrec++] = crec;
-			if (xdl_classify_record(pass, cf, rhash, hbits, crec) < 0)
+			if (xdl_classify_record(pass, cf, crec) < 0)
 				goto abort;
 		}
 	}
 
-	if (!XDL_CALLOC_ARRAY(rchg, nrec + 2))
+	if (!XDL_CALLOC_ARRAY(xdf->changed, xdf->nrec + 2))
 		goto abort;
 
 	if ((XDF_DIFF_ALG(xpp->flags) != XDF_PATIENCE_DIFF) &&
 	    (XDF_DIFF_ALG(xpp->flags) != XDF_HISTOGRAM_DIFF)) {
-		if (!XDL_ALLOC_ARRAY(rindex, nrec + 1))
-			goto abort;
-		if (!XDL_ALLOC_ARRAY(ha, nrec + 1))
+		if (!XDL_ALLOC_ARRAY(xdf->rindex, xdf->nrec + 1))
 			goto abort;
 	}
 
-	xdf->nrec = nrec;
-	xdf->recs = recs;
-	xdf->hbits = hbits;
-	xdf->rhash = rhash;
-	xdf->rchg = rchg + 1;
-	xdf->rindex = rindex;
+	xdf->changed += 1;
 	xdf->nreff = 0;
-	xdf->ha = ha;
 	xdf->dstart = 0;
-	xdf->dend = nrec - 1;
+	xdf->dend = xdf->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);
+	xdl_free_ctx(xdf);
 	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 (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;
-	}
-
-	xdl_free_classifier(&cf);
-
-	return 0;
-}
-
-
 void xdl_free_env(xdfenv_t *xe) {
 
 	xdl_free_ctx(&xe->xdf2);
@@ -300,15 +193,15 @@ void xdl_free_env(xdfenv_t *xe) {
 }
 
 
-static int xdl_clean_mmatch(char const *dis, long i, long s, long e) {
+static bool xdl_clean_mmatch(uint8_t const *action, 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.
+	 * Limits the window that is examined during the similar-lines
+	 * scan. The loops below stops when action[i - r] == KEEP
+	 * (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;
@@ -317,40 +210,47 @@ static int xdl_clean_mmatch(char const *dis, long i, long s, long e) {
 
 	/*
 	 * 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.
+	 * have no match (action[j] == DISCARD) or have multiple matches
+	 * (action[j] == INVESTIGATE). Note that we always call this
+	 * function with action[i] == INVESTIGATE, 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])
+		if (action[i - r] == DISCARD)
 			rdis0++;
-		else if (dis[i - r] == 2)
+		else if (action[i - r] == INVESTIGATE)
 			rpdis0++;
-		else
+		else if (action[i - r] == KEEP)
 			break;
+		else
+			BUG("Illegal value for action[i - r]");
 	}
 	/*
-	 * 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 the run before the line 'i' found only multimatch lines,
+	 * we return false 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
+	 * (action[j] == DISCARD).
 	 */
 	if (rdis0 == 0)
 		return 0;
 	for (r = 1, rdis1 = 0, rpdis1 = 1; (i + r) <= e; r++) {
-		if (!dis[i + r])
+		if (action[i + r] == DISCARD)
 			rdis1++;
-		else if (dis[i + r] == 2)
+		else if (action[i + r] == INVESTIGATE)
 			rpdis1++;
-		else
+		else if (action[i + r] == KEEP)
 			break;
+		else
+			BUG("Illegal value for action[i + r]");
 	}
 	/*
-	 * 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 the run after the line 'i' found only multimatch lines,
+	 * we return false and hence we don't make the current line (i)
+	 * discarded.
 	 */
 	if (rdis1 == 0)
-		return 0;
+		return false;
 	rdis1 += rdis0;
 	rpdis1 += rpdis0;
 
@@ -361,63 +261,81 @@ static int xdl_clean_mmatch(char const *dis, long i, long s, long e) {
 /*
  * 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.
+ * might be potentially discarded if they appear 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;
+	xrecord_t *recs;
 	xdlclass_t *rcrec;
-	char *dis, *dis1, *dis2;
-	int need_min = !!(cf->flags & XDF_NEED_MINIMAL);
+	uint8_t *action1 = NULL, *action2 = NULL;
+	bool need_min = !!(cf->flags & XDF_NEED_MINIMAL);
+	int ret = 0;
 
-	if (!XDL_CALLOC_ARRAY(dis, xdf1->nrec + xdf2->nrec + 2))
-		return -1;
-	dis1 = dis;
-	dis2 = dis1 + xdf1->nrec + 1;
+	/*
+	 * Create temporary arrays that will help us decide if
+	 * changed[i] should remain false, or become true.
+	 */
+	if (!XDL_CALLOC_ARRAY(action1, xdf1->nrec + 1)) {
+		ret = -1;
+		goto cleanup;
+	}
+	if (!XDL_CALLOC_ARRAY(action2, xdf2->nrec + 1)) {
+		ret = -1;
+		goto cleanup;
+	}
 
+	/*
+	 * Initialize temporary arrays with DISCARD, KEEP, or INVESTIGATE.
+	 */
 	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];
+		rcrec = cf->rcrecs[recs->ha];
 		nm = rcrec ? rcrec->len2 : 0;
-		dis1[i] = (nm == 0) ? 0: (nm >= mlim && !need_min) ? 2: 1;
+		action1[i] = (nm == 0) ? DISCARD: (nm >= mlim && !need_min) ? INVESTIGATE: KEEP;
 	}
 
 	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];
+		rcrec = cf->rcrecs[recs->ha];
 		nm = rcrec ? rcrec->len1 : 0;
-		dis2[i] = (nm == 0) ? 0: (nm >= mlim && !need_min) ? 2: 1;
+		action2[i] = (nm == 0) ? DISCARD: (nm >= mlim && !need_min) ? INVESTIGATE: KEEP;
 	}
 
+	/*
+	 * Use temporary arrays to decide if changed[i] should remain
+	 * false, or become true.
+	 */
 	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++;
+		if (action1[i] == KEEP ||
+		    (action1[i] == INVESTIGATE && !xdl_clean_mmatch(action1, i, xdf1->dstart, xdf1->dend))) {
+			xdf1->rindex[nreff++] = i;
+			/* changed[i] remains false, i.e. keep */
 		} else
-			xdf1->rchg[i] = 1;
+			xdf1->changed[i] = true;
+			/* i.e. discard */
 	}
 	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++;
+		if (action2[i] == KEEP ||
+		    (action2[i] == INVESTIGATE && !xdl_clean_mmatch(action2, i, xdf2->dstart, xdf2->dend))) {
+			xdf2->rindex[nreff++] = i;
+			/* changed[i] remains false, i.e. keep */
 		} else
-			xdf2->rchg[i] = 1;
+			xdf2->changed[i] = true;
+			/* i.e. discard */
 	}
 	xdf2->nreff = nreff;
 
-	xdl_free(dis);
+cleanup:
+	xdl_free(action1);
+	xdl_free(action2);
 
-	return 0;
+	return ret;
 }
 
 
@@ -426,13 +344,13 @@ static int xdl_cleanup_records(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xd
  */
 static int xdl_trim_ends(xdfile_t *xdf1, xdfile_t *xdf2) {
 	long i, lim;
-	xrecord_t **recs1, **recs2;
+	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)
+		if (recs1->ha != recs2->ha)
 			break;
 
 	xdf1->dstart = xdf2->dstart = i;
@@ -440,7 +358,7 @@ static int xdl_trim_ends(xdfile_t *xdf1, xdfile_t *xdf2) {
 	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)
+		if (recs1->ha != recs2->ha)
 			break;
 
 	xdf1->dend = xdf1->nrec - i - 1;
@@ -460,3 +378,53 @@ static int xdl_optimize_ctxs(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xdf2
 
 	return 0;
 }
+
+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 (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;
+	}
+
+	xdl_free_classifier(&cf);
+
+	return 0;
+}