Use dynamic memory instead of a fixed table. Makes merges files with

lots of changes possible. While there, kill an off-by-one.
Report and testing by Alexander Bluhm. ok millert@

1 files changed, 57 insertions, 19 deletions

diff --git a/usr.bin/diff3/diff3prog.c b/usr.bin/diff3/diff3prog.c
index 04f3ce68b11..7e109b04de6 100644
--- a/usr.bin/diff3/diff3prog.c
+++ b/usr.bin/diff3/diff3prog.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: diff3prog.c,v 1.6 2005/03/30 04:44:52 millert Exp $	*/
+/*	$OpenBSD: diff3prog.c,v 1.7 2005/08/01 08:17:57 otto Exp $	*/
 
 /*
  * Copyright (C) Caldera International Inc.  2001-2002.
@@ -71,7 +71,7 @@ static const char copyright[] =
 #endif /* not lint */
 
 #ifndef lint
-static const char rcsid[] = "$OpenBSD: diff3prog.c,v 1.6 2005/03/30 04:44:52 millert Exp $";
+static const char rcsid[] = "$OpenBSD: diff3prog.c,v 1.7 2005/08/01 08:17:57 otto Exp $";
 #endif /* not lint */
 
 #include <stdio.h>
@@ -105,9 +105,10 @@ struct diff {
 	struct range new;
 };
 
-#define NC 200
-struct diff d13[NC];
-struct diff d23[NC];
+size_t szchanges;
+
+struct diff *d13;
+struct diff *d23;
 /*
  * "de" is used to gather editing scripts.  These are later spewed out in
  * reverse order.  Its first element must be all zero, the "new" component
@@ -115,8 +116,8 @@ struct diff d23[NC];
  * look (!?).  Array overlap indicates which sections in "de" correspond to
  * lines that are different in all three files.
  */
-struct diff de[NC];
-char overlap[NC];
+struct diff *de;
+char *overlap;
 int  overlapcnt;
 FILE *fp[3];
 int cline[3];		/* # of the last-read line in each file (0-2) */
@@ -135,7 +136,7 @@ int edit(struct diff *, int, int);
 char *getchange(FILE *);
 char *getline(FILE *, size_t *);
 int number(char **);
-int readin(char *, struct diff *);
+int readin(char *, struct diff **);
 int skip(int, int, char *);
 void change(int, struct range *, int);
 void keep(int, struct range *);
@@ -145,6 +146,7 @@ void repos(int);
 void separate(const char *);
 __dead void edscript(int);
 __dead void trouble(void);
+void increase(void);
 __dead void usage(void);
 
 int
@@ -187,8 +189,9 @@ main(int argc, char **argv)
 		    argc >= 7 ? argv[6] : argv[4]);
 	}
 
-	m = readin(argv[0], d13);
-	n = readin(argv[1], d23);
+	increase();
+	m = readin(argv[0], &d13);
+	n = readin(argv[1], &d23);
 	for (i = 0; i <= 2; i++) {
 		if ((fp[i] = fopen(argv[i + 2], "r")) == NULL) {
 			printf("diff3: can't open %s\n", argv[i + 2]);
@@ -206,15 +209,15 @@ main(int argc, char **argv)
  * The vector could be optimized out of existence)
  */
 int
-readin(char *name, struct diff *dd)
+readin(char *name, struct diff **dd)
 {
 	int a, b, c, d, i;
 	char kind, *p;
 
 	fp[0] = fopen(name, "r");
 	for (i=0; (p = getchange(fp[0])); i++) {
-		if (i >= NC)
-			err(EXIT_FAILURE, "too many changes");
+		if (i >= szchanges - 1)
+			increase();
 		a = b = number(&p);
 		if (*p == ',') {
 			p++;
@@ -232,13 +235,13 @@ readin(char *name, struct diff *dd)
 			c++;
 		b++;
 		d++;
-		dd[i].old.from = a;
-		dd[i].old.to = b;
-		dd[i].new.from = c;
-		dd[i].new.to = d;
+		(*dd)[i].old.from = a;
+		(*dd)[i].old.to = b;
+		(*dd)[i].new.from = c;
+		(*dd)[i].new.to = d;
 	}
-	dd[i].old.from = dd[i-1].old.to;
-	dd[i].new.from = dd[i-1].new.to;
+	(*dd)[i].old.from = (*dd)[i-1].old.to;
+	(*dd)[i].new.from = (*dd)[i-1].new.to;
 	(void)fclose(fp[0]);
 	return (i);
 }
@@ -566,6 +569,41 @@ edscript(int n)
 	exit(overlapcnt);
 }
 
+void
+increase(void)
+{
+	struct diff *p;
+	char *q;
+	size_t newsz, incr;
+
+	/* are the memset(3) calls needed? */
+	newsz = szchanges == 0 ? 64 : 2 * szchanges;
+	incr = newsz - szchanges;
+
+	p = realloc(d13, newsz * sizeof(struct diff));
+	if (p == NULL)
+		err(1, NULL);
+	memset(p + szchanges, 0, incr * sizeof(struct diff));
+	d13 = p;
+	p = realloc(d23, newsz * sizeof(struct diff));
+	if (p == NULL)
+		err(1, NULL);
+	memset(p + szchanges, 0, incr * sizeof(struct diff));
+	d23 = p;
+	p = realloc(de, newsz * sizeof(struct diff));
+	if (p == NULL)
+		err(1, NULL);
+	memset(p + szchanges, 0, incr * sizeof(struct diff));
+	de = p;
+	q = realloc(overlap, newsz * sizeof(char));
+	if (q == NULL)
+		err(1, NULL);
+	memset(q + szchanges, 0, incr * sizeof(char));
+	overlap = q;
+	szchanges = newsz;
+}
+
+
 __dead void
 usage(void)
 {