C: Json comments: added an obi_read_comment function to read one value

from comments

src/libjson/json_utils.c

@@ -238,7 +238,45 @@ char* obi_add_comment(char* comments, const char* key, const char* value)
 
 	// Free structure
 	cJSON_Delete(comments_struct);
+
 	return new_comments;
 }
 
 
+char* obi_read_comment(char* comments, const char* key)
+{
+	cJSON* comments_struct = NULL;
+	cJSON* value_json      = NULL;
+	char*  value           = NULL;
+
+	comments_struct = cJSON_Parse(comments);
+	if (comments_struct == NULL)
+	{
+		obi_set_errno(OBI_JSON_ERROR);
+		obidebug(1, "\nError parsing the comments when reading comments, key: %s", key);
+		return NULL;
+	}
+
+	value_json = cJSON_GetObjectItem(comments_struct, key);
+	if (value_json == NULL)
+	{
+		obi_set_errno(OBI_JSON_ERROR);
+		obidebug(1, "\nError getting a value when reading a comment, key: %s", key);
+		return NULL;
+	}
+
+	value = cJSON_Print(value_json);
+	if (value == NULL)
+	{
+		obi_set_errno(OBI_JSON_ERROR);
+		obidebug(1, "\nError formatting a value when reading a comment, key: %s", key);
+		return NULL;
+	}
+
+	// Free structure
+	cJSON_Delete(comments_struct);
+
+	return value;
+}
+
+