yanglint REFACTOR schema_features in separate file
diff --git a/tools/lint/yl_schema_features.h b/tools/lint/yl_schema_features.h
new file mode 100644
index 0000000..b697dcc
--- /dev/null
+++ b/tools/lint/yl_schema_features.h
@@ -0,0 +1,102 @@
+/**
+ * @file yl_schema_features.h
+ * @author Adam Piecek <piecek@cesnet.cz>
+ * @brief Control features for the schema.
+ *
+ * Copyright (c) 2023 CESNET, z.s.p.o.
+ *
+ * This source code is licensed under BSD 3-Clause License (the "License").
+ * You may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://opensource.org/licenses/BSD-3-Clause
+ */
+
+#ifndef YL_SCHEMA_FEATURES_H_
+#define YL_SCHEMA_FEATURES_H_
+
+#include <stdint.h>
+
+struct ly_set;
+struct lys_module;
+struct ly_out;
+struct ly_ctx;
+
+/**
+ * @brief Storage for the list of the features (their names) in a specific YANG module.
+ */
+struct schema_features {
+    char *mod_name;
+    char **features;
+    uint8_t applied;
+};
+
+/**
+ * @brief Free the schema features list (struct schema_features *)
+ * @param[in,out] flist The (struct schema_features *) to free.
+ */
+void yl_schema_features_free(void *flist);
+
+/**
+ * @brief Get the list of features connected with the specific YANG module.
+ *
+ * @param[in] fset The set of features information (struct schema_features *).
+ * @param[in] module Name of the YANG module which features should be found.
+ * @param[out] features Pointer to the list of features being returned.
+ */
+void get_features(const struct ly_set *fset, const char *module, const char ***features);
+
+/**
+ * @brief Parse features being specified for the specific YANG module.
+ *
+ * Format of the input @p fstring is as follows: "<module_name>:[<feature>,]*"
+ *
+ * @param[in] fstring Input string to be parsed.
+ * @param[in, out] fset Features information set (of struct schema_features *). The set is being filled.
+ */
+int parse_features(const char *fstring, struct ly_set *fset);
+
+/**
+ * @brief Collect all features of a module.
+ *
+ * @param[in] mod Module to be searched for features.
+ * @param[out] set Set in which the features will be stored.
+ * @return 0 on success.
+ * @return 1 on error.
+ */
+int collect_features(const struct lys_module *mod, struct ly_set *set);
+
+/**
+ * @brief Print all features of a single module.
+ *
+ * @param[in] out The output handler for printing.
+ * @param[in] mod Module which contains the features.
+ * @param[in] set Set which holds the features.
+ */
+void print_features(struct ly_out *out, const struct lys_module *mod, const struct ly_set *set);
+
+/**
+ * @brief Generate a string, which will contain features paramater.
+ *
+ * @param[in] mod Module, for which the string will be generated.
+ * @param[in] set Set containing the features.
+ * @param[out] features_param String which will contain the output.
+ * @return 0 on success.
+ * @return 1 on error.
+ */
+int generate_features_output(const struct lys_module *mod, const struct ly_set *set, char **features_param);
+
+/**
+ * @brief Print all features of all implemented modules.
+ *
+ * @param[in] out The output handler for printing.
+ * @param[in] ctx Libyang context.
+ * @param[in] generate_features Flag expressing whether to generate features parameter.
+ * @param[out] features_param String, which will contain the output if the above flag is set.
+ * @return 0 on success.
+ * @return 1 on error.
+ */
+int print_all_features(struct ly_out *out, const struct ly_ctx *ctx, uint8_t generate_features, char **features_param);
+
+
+#endif /* YL_SCHEMA_FEATURES_H_ */