awk: fix dodgy multi-char separators splitting logic

function                                             old     new   delta
awk_split                                            521     484     -37

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 16 insertions, 9 deletions

diff --git a/editors/awk.c b/editors/awk.c
index f7451ae32..59dae4770 100644
--- a/editors/awk.c
+++ b/editors/awk.c
@@ -1765,10 +1765,9 @@ static void fsrealloc(int size)
 
 static int awk_split(const char *s, node *spl, char **slist)
 {
-        int l, n;
+        int n;
         char c[4];
         char *s1;
-        regmatch_t pmatch[2]; // TODO: why [2]? [1] is enough...
 
         /* in worst case, each char would be a separate field */
         *slist = s1 = xzalloc(strlen(s) * 2 + 3);
@@ -1785,12 +1784,18 @@ static int awk_split(const char *s, node *spl, char **slist)
                         return n; /* "": zero fields */
                 n++; /* at least one field will be there */
                 do {
+                        int l;
+                        regmatch_t pmatch[2]; // TODO: why [2]? [1] is enough...
+
                         l = strcspn(s, c+2); /* len till next NUL or \n */
                         if (regexec(icase ? spl->r.ire : spl->l.re, s, 1, pmatch, 0) == 0
                          && pmatch[0].rm_so <= l
                         ) {
                                 l = pmatch[0].rm_so;
                                 if (pmatch[0].rm_eo == 0) {
+                                        /* For example, happens when FS can match
+                                         * an empthy string (awk -F ' *')
+                                         */
                                         l++;
                                         pmatch[0].rm_eo++;
                                 }
@@ -1800,14 +1805,16 @@ static int awk_split(const char *s, node *spl, char **slist)
                                 if (s[l])
                                         pmatch[0].rm_eo++;
                         }
-                        memcpy(s1, s, l);
-                        /* make sure we remove *all* of the separator chars */
-                        do {
-                                s1[l] = '\0';
-                        } while (++l < pmatch[0].rm_eo);
-                        nextword(&s1);
+                        s1 = mempcpy(s1, s, l);
+                        *s1++ = '\0';
                         s += pmatch[0].rm_eo;
                 } while (*s);
+
+                /* echo a-- | awk -F-- '{ print NF, length($NF), $NF }'
+                 * should print "2 0 ":
+                 */
+                *s1 = '\0';
+
                 return n;
         }
         if (c[0] == '\0') {  /* null split */
@@ -2011,7 +2018,7 @@ static int ptest(node *pattern)
 static int awk_getline(rstream *rsm, var *v)
 {
         char *b;
-        regmatch_t pmatch[2];
+        regmatch_t pmatch[2]; // TODO: why [2]? [1] is enough...
         int size, a, p, pp = 0;
         int fd, so, eo, r, rp;
         char c, *m, *s;