- size_t remain;
-
- if (s1 != NULL) old = s1;
- if (old == NULL) return (NULL);
- p = old;
- len = strspn(p, s2);
- remain = strlen(p);
- if (remain <= len) { old = NULL; return (NULL); }
- p += len;
- len = strcspn(p, s2);
- remain = strlen(p);
- if (remain <= len) { old = NULL; return (p); }
- *(p + len) = '\0';
- old = p + len + 1;
- return (p);
+
+ if ( s1 != NULL )
+ {
+ /* new string */
+ tmp = s1;
+ }
+ else
+ {
+ /* old string continued */
+ if ( tmp == NULL )
+ {
+ /* No old string, no new string, nothing to do */
+ return NULL;
+ }
+ s1 = tmp;
+ }
+
+ /* skipping leading s2 characters */
+ while ( *p && *s1 )
+ {
+ if ( *s1 == *p )
+ {
+ /* found seperator; skip and start over */
+ ++s1;
+ p = s2;
+ continue;
+ }
+ ++p;
+ }
+
+ if ( ! *s1 )
+ {
+ /* no more to parse */
+ return ( tmp = NULL );
+ }
+
+ /* skipping non-s2 characters */
+ tmp = s1;
+ while ( *tmp )
+ {
+ p = s2;
+ while ( *p )
+ {
+ if ( *tmp == *p++ )
+ {
+ /* found seperator; overwrite with '\0', position tmp, return */
+ *tmp++ = '\0';
+ return s1;
+ }
+ }
+ ++tmp;
+ }
+
+ /* parsed to end of string */
+ return ( tmp = NULL );