2 files changed, 27 insertions, 4 deletions

diff --git a/tools/perf/util/strlist.c b/tools/perf/util/strlist.c
index 025a78edfffe..7ad38171dc2b 100644
--- a/tools/perf/util/strlist.c
+++ b/tools/perf/util/strlist.c
@@ -64,6 +64,7 @@ int strlist__add(struct strlist *self, const char *new_entry)
 
         rb_link_node(&sn->rb_node, parent, p);
         rb_insert_color(&sn->rb_node, &self->entries);
+        ++self->nr_entries;
 
         return 0;
 }
@@ -155,8 +156,9 @@ struct strlist *strlist__new(bool dupstr, const char *slist)
         struct strlist *self = malloc(sizeof(*self));
 
         if (self != NULL) {
-                self->entries = RB_ROOT;
-                self->dupstr = dupstr;
+                self->entries    = RB_ROOT;
+                self->dupstr     = dupstr;
+                self->nr_entries = 0;
                 if (slist && strlist__parse_list(self, slist) != 0)
                         goto out_error;
         }
@@ -182,3 +184,17 @@ void strlist__delete(struct strlist *self)
                 free(self);
         }
 }
+
+struct str_node *strlist__entry(const struct strlist *self, unsigned int idx)
+{
+        struct rb_node *nd;
+
+        for (nd = rb_first(&self->entries); nd; nd = rb_next(nd)) {
+                struct str_node *pos = rb_entry(nd, struct str_node, rb_node);
+
+                if (!idx--)
+                        return pos;
+        }
+
+        return NULL;
+}
diff --git a/tools/perf/util/strlist.h b/tools/perf/util/strlist.h
index 2fdcfee87586..921818e44a54 100644
--- a/tools/perf/util/strlist.h
+++ b/tools/perf/util/strlist.h
@@ -11,7 +11,8 @@ struct str_node {
 
 struct strlist {
         struct rb_root entries;
-        bool dupstr;
+        unsigned int   nr_entries;
+        bool           dupstr;
 };
 
 struct strlist *strlist__new(bool dupstr, const char *slist);
@@ -21,11 +22,17 @@ void strlist__remove(struct strlist *self, struct str_node *sn);
 int strlist__load(struct strlist *self, const char *filename);
 int strlist__add(struct strlist *self, const char *str);
 
+struct str_node *strlist__entry(const struct strlist *self, unsigned int idx);
 bool strlist__has_entry(struct strlist *self, const char *entry);
 
 static inline bool strlist__empty(const struct strlist *self)
 {
-        return rb_first(&self->entries) == NULL;
+        return self->nr_entries == 0;
+}
+
+static inline unsigned int strlist__nr_entries(const struct strlist *self)
+{
+        return self->nr_entries;
 }
 
 int strlist__parse_list(struct strlist *self, const char *s);