[hackers] [sbase][PATCH] [ed] Do not try to rematch patterns with ^ or $

From: Roberto E. Vargas Caballero <k0ga_AT_shike2.com>
Date: Sat, 23 Jan 2016 09:15:14 +0100

It is impossible to rematch a pattern which has one (or both)
of these operators, so the simplest solucion is detect them
while we are compiling the regular expression and break the
match loop after the first iteration.

---
 ed.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/ed.c b/ed.c
index 9dc6fda..0ec0574 100644
--- a/ed.c
+++ b/ed.c
_AT_@ -63,6 +63,7 @@ static char *rhs;
 static char *lastmatch;
 static struct undo udata;
 static int newcmd;
+int eol, bol;
 
 
 
_AT_@ -360,11 +361,15 @@ compile(int delim)
 	if (!isgraph(delim))
 		error("invalid pattern delimiter");
 
-	bracket = siz = 0;
+	eol = bol = bracket = siz = 0;
 	for (n = 0;; ++n) {
 		if ((c = input()) == delim && !bracket)
 			break;
-		if (c == '\n' || c == EOF) {
+		if (c == '^') {
+			bol = 1;
+		} else if (c == '$') {
+			eol = 1;
+		} else if (c == '\n' || c == EOF) {
 			back(c);
 			break;
 		}
_AT_@ -1007,9 +1012,11 @@ subline(int num, int nth)
 	static size_t siz, cap;
 
 	i = changed = siz = 0;
-	for (m = match(num); m && *lastmatch != '\n'; m = rematch(num)) {
+	for (m = match(num); m; m = rematch(num)) {
 		addpre(&s, &cap, &siz);
 		changed |= addsub(&s, &cap, &siz, nth, ++i);
+		if (eol || bol)
+			break;
 	}
 	if (!changed)
 		return;
-- 
2.1.4

Received on Sat Jan 23 2016 - 09:15:14 CET