Allow adding new states with levels

include/mata/nft/nft.hh

@@ -106,11 +106,23 @@ public:
     State add_state();
 
     /**
-     * Add state @p state to @c delta if @p state is not in @c delta yet.
+     * Add state @p state to @c this with level @p level if @p state is not in @c this yet.
      * @return The requested @p state.
      */
     State add_state(State state);
 
+    /**
+     * Add a new (fresh) state to the automaton with level @p level.
+     * @return The newly created state.
+     */
+    State add_state_with_level(Level level);
+
+    /**
+     * Add state @p state to @c this with level @p level if @p state is not in @c this yet.
+     * @return The requested @p state.
+     */
+    State add_state_with_level(State state, Level level);
+
     /**
      * @brief Clear the underlying NFT to a blank NFT.
      *

src/nft/nft.cc

@@ -272,16 +272,26 @@ State Nft::add_state() {
     return mata::nfa::Nfa::add_state();
 }
 
-State Nft::add_state(State state) {
-    const size_t levels_size = levels.size();
-    if (state >= levels_size) {
-        levels.resize(state + 1);
-        const size_t begin_idx = (levels_size == 0) ? 0 : levels_size - 1;
-        std::fill(levels.begin() + static_cast<long int>(begin_idx), levels.end(), 0);
+State Nft::add_state(const State state) {
+    const size_t required_capacity{ state + 1 };
+    if (levels.size() < required_capacity) {
+        levels.resize(required_capacity, DEFAULT_LEVEL);
     }
     return mata::nfa::Nfa::add_state(state);
 }
 
+State Nft::add_state_with_level(const Level level) {
+    const State state{ add_state() };
+    levels[state] = level;
+    return state;
+}
+
+State Nft::add_state_with_level(const State state, const Level level) {
+    add_state(state);
+    levels[state] = level;
+    return mata::nfa::Nfa::add_state(state);
+}
+
 void Nft::clear() {
     mata::nfa::Nfa::clear();
     levels.clear();

tests/nft/nft.cc

@@ -3125,3 +3125,22 @@ TEST_CASE("mata::nft::Nft::get_one_level_aut") {
     }
 
 }
+
+TEST_CASE("mata::nft::Nft::add_state()") {
+    Nft nft{};
+    State state{ nft.add_state() };
+    CHECK(state == 0);
+    CHECK(nft.levels[state] == 0);
+    state = nft.add_state(4);
+    CHECK(state == 4);
+    CHECK(nft.levels[state] == 0);
+    CHECK(nft.num_of_states() == 5);
+    state = nft.add_state_with_level(3);
+    CHECK(state == 5);
+    CHECK(nft.levels[state] == 3);
+    CHECK(nft.num_of_states() == 6);
+    state = nft.add_state_with_level(12, 1);
+    CHECK(state == 12);
+    CHECK(nft.levels[state] == 1);
+    CHECK(nft.num_of_states() == 13);
+}