[hackers] [sbase][PATCH v2] Fix pattern substitution

[Roberto E. Vargas Caballero]

Ed was falling doing substitution different of the first or all
(s//%/, s//%/\1, s//%/g), because it was not adding the matches
which were not going to be substituted.
---
 ed.c | 26 +++---
 1 file changed, 15 insertions(+), 11 deletions(-)

diff --git a/ed.c b/ed.c
index 77aad19..69c7422 100644
--- a/ed.c
+++ b/ed.c
@@ -959,12 +959,20 @@ addpost(char **s, size_t *cap, size_t *siz)
*s = addchar('\0', *s, cap, siz);
 }
 
-static void
-addsub(char **s, size_t *cap, size_t *siz)
+static int
+addsub(char **s, size_t *cap, size_t *siz, int nth, int nmatch)
 {
char *end, *q, *p, c;
int sub;
 
+   if (nth != nmatch && nth != -1) {
+   q   = lastmatch + matchs[0].rm_so;
+   end = lastmatch + matchs[0].rm_eo;
+   while (q < end)
+   *s = addchar(*q++, *s, cap, siz);
+   return 0;
+   }
+
for (p = rhs; (c = *p); ++p) {
switch (c) {
case '&':
@@ -972,7 +980,7 @@ addsub(char **s, size_t *cap, size_t *siz)
goto copy_match;
case '\\':
if ((c = *++p) == '\0')
-   return;
+   return 1;
if (!isdigit(c))
goto copy_char;
sub = c - '0';
@@ -988,24 +996,20 @@ addsub(char **s, size_t *cap, size_t *siz)
break;
}
}
+   return 1;
 }
 
 static void
 subline(int num, int nth)
 {
-   int m, changed;
+   int i, m, changed;
static char *s;
static size_t siz, cap;
 
-   siz = 0;
+   i = changed = siz = 0;
for (m = match(num); m; m = rematch(num)) {
addpre(, , );
-   if (--nth > 0)
-   continue;
-   changed = 1;
-   addsub(, , );
-   if (nth == 0)
-   break;
+   changed |= addsub(, , , nth, ++i);
}
if (!changed)
return;
-- 
2.1.4

[hackers] [sbase][PATCH] Stop matching when lastmatch points to '\n'

[Roberto E. Vargas Caballero]

This situation happens with something like s/$/test/,
where rm_so == rm_eo == 0. Without this check, ed
keeps looping forever.
---
 ed.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ed.c b/ed.c
index 69c7422..9dc6fda 100644
--- a/ed.c
+++ b/ed.c
@@ -1007,7 +1007,7 @@ subline(int num, int nth)
static size_t siz, cap;
 
i = changed = siz = 0;
-   for (m = match(num); m; m = rematch(num)) {
+   for (m = match(num); m && *lastmatch != '\n'; m = rematch(num)) {
addpre(, , );
changed |= addsub(, , , nth, ++i);
}
-- 
2.1.4