4 files changed, 49 insertions, 2 deletions
diff --git a/src/libnetdata/string/README.md b/src/libnetdata/string/README.md
new file mode 100644
index 000000000..54c905946
--- /dev/null
+++ b/src/libnetdata/string/README.md
@@ -0,0 +1,25 @@
+<!--
+title: "String"
+custom_edit_url: https://github.com/netdata/netdata/edit/master/src/libnetdata/string/README.md
+sidebar_label: "String"
+learn_status: "Published"
+learn_topic_type: "Tasks"
+learn_rel_path: "Developers/libnetdata"
+-->
+
+# STRING
+
+STRING provides a way to allocate and free text strings, while de-duplicating them.
+
+It can be used similarly to libc string functions:
+
+ - `strdup()` and `strdupz()` become `string_strdupz()`.
+ - `strlen()` becomes `string_strlen()` (and it does not walkthrough the bytes of the string).
+ - `free()` and `freez()` become `string_freez()`.
+
+There is also a special `string_dup()` function that increases the reference counter of a STRING, avoiding the
+index lookup to find it.
+
+Once there is a `STRING *`, the actual `const char *` can be accessed with `string2str()`.
+
+All STRING should be constant. Changing the contents of a `const char *` that has been acquired by `string2str()` should never happen. 
diff --git a/libnetdata/string/string.c b/src/libnetdata/string/string.c
index e1c8352a5..0b4a6470d 100644
--- a/libnetdata/string/string.c
+++ b/src/libnetdata/string/string.c
@@ -88,8 +88,8 @@ void string_statistics(size_t *inserts, size_t *deletes, size_t *searches, size_
     }
 }
 
-#define string_entry_acquire(se) __atomic_add_fetch(&((se)->refcount), 1, __ATOMIC_SEQ_CST);
-#define string_entry_release(se) __atomic_sub_fetch(&((se)->refcount), 1, __ATOMIC_SEQ_CST);
+#define string_entry_acquire(se) __atomic_add_fetch(&((se)->refcount), 1, __ATOMIC_SEQ_CST)
+#define string_entry_release(se) __atomic_sub_fetch(&((se)->refcount), 1, __ATOMIC_SEQ_CST)
 
 static inline bool string_entry_check_and_acquire(STRING *se) {
 #ifdef NETDATA_INTERNAL_CHECKS
@@ -307,6 +307,25 @@ STRING *string_strdupz(const char *str) {
     return string;
 }
 
+STRING *string_strndupz(const char *str, size_t len) {
+    if(unlikely(!str || !*str || !len)) return NULL;
+
+#ifdef NETDATA_INTERNAL_CHECKS
+    uint8_t partition = string_partition_str(str);
+#endif
+
+    char buf[len + 1];
+    memcpy(buf, str, len);
+    buf[len] = '\0';
+
+    STRING *string = string_index_search(buf, len + 1);
+    while(!string)
+        string = string_index_insert(buf, len + 1);
+
+    string_stats_atomic_increment(partition, active_references);
+    return string;
+}
+
 void string_freez(STRING *string) {
     if(unlikely(!string)) return;
 
diff --git a/libnetdata/string/string.h b/src/libnetdata/string/string.h
index ba0e3876b..f2ff9666c 100644
--- a/libnetdata/string/string.h
+++ b/src/libnetdata/string/string.h
@@ -8,7 +8,10 @@
 // STRING implementation
 
 typedef struct netdata_string STRING;
+
 STRING *string_strdupz(const char *str);
+STRING *string_strndupz(const char *str, size_t len);
+
 STRING *string_dup(STRING *string);
 void string_freez(STRING *string);
 size_t string_strlen(STRING *string);
diff --git a/libnetdata/string/utf8.h b/src/libnetdata/string/utf8.h
index 3e6c8c288..3e6c8c288 100644
--- a/libnetdata/string/utf8.h
+++ b/src/libnetdata/string/utf8.h