Add _z_id_to_string function (#608)

* fix: z_string_convert_bytes

* feat: add z_id_to_string

* fix update function name

include/zenoh-pico/api/primitives.h

@@ -1533,6 +1533,18 @@ int8_t z_info_routers_zid(const z_loaned_session_t *zs, z_moved_closure_zid_t *c
  */
 z_id_t z_info_zid(const z_loaned_session_t *zs);
 
+/**
+ * Converts a Zenoh ID into a string for print purposes.
+ *
+ * Parameters:
+ *   str: Pointer to uninitialized :c:type:`z_owned_string_t` to store the string.
+ *   id: Pointer to the id to convert.
+ *
+ * Return:
+ *   ``0`` if operation successful, ``negative value`` otherwise.
+ */
+z_result_t z_id_to_string(z_owned_string_t *str, z_id_t *id);
+
 /**
  * Gets the keyexpr from a sample by aliasing it.
  *

src/api/api.c

@@ -968,6 +968,15 @@ int8_t z_info_routers_zid(const z_loaned_session_t *zs, z_moved_closure_zid_t *c
 
 z_id_t z_info_zid(const z_loaned_session_t *zs) { return _Z_RC_IN_VAL(zs)->_local_zid; }
 
+z_result_t z_id_to_string(z_owned_string_t *str, z_id_t *id) {
+    _z_slice_t buf = _z_slice_alias_buf(id->id, sizeof(id->id));
+    str->_val = _z_string_convert_bytes(&buf);
+    if (!_z_string_check(&str->_val)) {
+        return _Z_ERR_SYSTEM_OUT_OF_MEMORY;
+    }
+    return _Z_RES_OK;
+}
+
 const z_loaned_keyexpr_t *z_sample_keyexpr(const z_loaned_sample_t *sample) { return &sample->keyexpr; }
 z_sample_kind_t z_sample_kind(const z_loaned_sample_t *sample) { return sample->kind; }
 const z_loaned_bytes_t *z_sample_payload(const z_loaned_sample_t *sample) { return &sample->payload; }

src/collections/string.c

@@ -119,17 +119,12 @@ _z_string_t _z_string_convert_bytes(const _z_slice_t *bs) {
         return s;
     }
 
-    if (s_val != NULL) {
-        const char c[] = "0123456789ABCDEF";
-        for (size_t i = 0; i < bs->len; i++) {
-            s_val[i * (size_t)2] = c[(bs->start[i] & (uint8_t)0xF0) >> (uint8_t)4];
-            s_val[(i * (size_t)2)] = c[bs->start[i] & (uint8_t)0x0F];
-        }
-    } else {
-        len = 0;
+    const char c[] = "0123456789ABCDEF";
+    for (size_t i = 0; i < bs->len; i++) {
+        s_val[i * (size_t)2] = c[(bs->start[i] & (uint8_t)0xF0) >> (uint8_t)4];
+        s_val[(i * (size_t)2) + 1] = c[bs->start[i] & (uint8_t)0x0F];
     }
     s._slice = _z_slice_from_buf_custom_deleter((const uint8_t *)s_val, len, _z_delete_context_default());
-
     return s;
 }