fix: Fix DFA unit test failure mentioned in #10; Fix linting workflow by applying cargo fmt.

examples/src/main.rs

@@ -1,7 +1,7 @@
 use log_surgeon::error_handling::Result;
-use log_surgeon::parser::SchemaConfig;
 use log_surgeon::log_parser::LogEvent;
 use log_surgeon::log_parser::LogParser;
+use log_surgeon::parser::SchemaConfig;
 
 use std::rc::Rc;
 
@@ -12,7 +12,9 @@ fn main() -> Result<()> {
         .join("logs")
         .join("simple.log");
 
-    let parsed_schema = Rc::new(SchemaConfig::parse_from_file(schema_path.to_str().unwrap())?);
+    let parsed_schema = Rc::new(SchemaConfig::parse_from_file(
+        schema_path.to_str().unwrap(),
+    )?);
     let mut log_parser = LogParser::new(parsed_schema.clone())?;
     log_parser.set_input_file(log_path.to_str().unwrap())?;
 

src/dfa/dfa.rs

@@ -7,6 +7,7 @@ use std::rc::Rc;
 #[derive(Clone, Debug, Eq, Hash, PartialEq)]
 pub struct State(usize);
 
+#[derive(Clone)]
 enum Tag {
     Start(usize),
     End(usize),
@@ -48,15 +49,15 @@ pub(crate) struct DFA {
     start: State,
     accept: Vec<State>,
     states: Vec<State>,
-    transitions: Vec<HashMap<u128, Transition>>, // from_state -> symbol -> to_state
+    transitions: Vec<Vec<Option<Transition>>>, // from_state -> symbol[index in the length 128 vector] -> transition
     dfa_to_accepted_nfa_state_mapping: Vec<Option<(usize, crate::nfa::nfa::State)>>, // to determine which NFA gets matched
 }
 
 impl Debug for DFA {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         write!(
             f,
-            "NFA( start: {:?}, accept: {:?}, states: {:?}, transitions: {{\n",
+            "DFA( start: {:?}, accept: {:?}, states: {:?}, transitions: {{\n",
             self.start, self.accept, self.states
         )?;
 
@@ -66,8 +67,11 @@ impl Debug for DFA {
                 continue;
             }
             write!(f, "\t{:?}:\n", state)?;
-            for (_, transition) in &self.transitions[state_idx] {
-                write!(f, "\t\t{:?}\n", transition)?;
+            for transition_option in self.transitions[state_idx].iter() {
+                if transition_option.is_none() {
+                    continue;
+                }
+                write!(f, "\t\t{:?}\n", transition_option.as_ref().unwrap())?;
             }
         }
 
@@ -87,7 +91,11 @@ impl DFA {
         _states.push(State(0)); // start state is always 0
 
         let mut _transitions = Vec::new();
-        _transitions.push(HashMap::new());
+        let mut vector = Vec::with_capacity(128);
+        for _ in 0..128 {
+            vector.push(None::<Transition>);
+        }
+        _transitions.push(vector);
 
         DFA {
             start: State(0),
@@ -109,28 +117,29 @@ impl DFA {
         assert!(self.transitions.len() > from_state.0);
         assert!(self.states.len() > to_state.0);
 
-        self.transitions.get_mut(from_state.0).unwrap().insert(
-            symbol_onehot_encoding,
-            Transition {
-                from_state,
-                symbol_onehot_encoding,
-                to_state,
-                tag,
-            },
-        );
+        for i in 0..128 {
+            if (symbol_onehot_encoding & (1 << i)) != 0 {
+                assert_eq!(self.transitions[from_state.0].len(), 128);
+                self.transitions[from_state.0][i] = Some(Transition {
+                    from_state: from_state.clone(),
+                    symbol_onehot_encoding,
+                    to_state: to_state.clone(),
+                    tag: tag.clone(),
+                });
+            }
+        }
     }
 
     fn get_transition(
-        transitions_map: &HashMap<u128, Transition>,
+        transitions_map: &Vec<Option<Transition>>,
         symbol: char,
     ) -> Option<&Transition> {
-        for (transition_symbol, transition) in transitions_map.iter() {
-            if (*transition_symbol & (1 << (symbol as u8))) != 0 {
-                return Some(transition);
-            }
+        let transition = transitions_map.get(symbol as usize);
+        if transition.is_none() {
+            return None;
         }
 
-        None
+        transition.unwrap().as_ref()
     }
 
     fn get_accept_nfa_state(&self, s: usize) -> Option<usize> {
@@ -217,15 +226,14 @@ impl DFA {
 
 impl DFA {
     pub fn get_next_state(&self, state: State, c: u8) -> Option<State> {
-        // No bound check
         let transitions = &self.transitions[state.0];
-        let mask = 1u128 << c;
-        for (transition_symbol, transition) in transitions.iter() {
-            if mask & transition_symbol == mask {
-                return Some(transition.to_state.clone());
-            }
+        if 128 <= c {
+            return None;
+        }
+        match &transitions[c as usize] {
+            Some(transition) => Some(transition.to_state.clone()),
+            None => None,
         }
-        None
     }
 
     pub fn is_accept_state(&self, state: State) -> Option<usize> {
@@ -250,7 +258,7 @@ impl DFA {
         let mut dfa_to_accepted_nfa_state_mapping: Vec<Option<(usize, crate::nfa::nfa::State)>> =
             Vec::new();
         let mut dfa_accept_states = HashSet::new();
-        let mut dfa_transitions: Vec<HashMap<u128, Transition>> = Vec::new();
+        let mut dfa_transitions: Vec<Vec<Option<Transition>>> = Vec::new();
 
         // local variables to help create the DFA
         let mut l_worklist: Vec<State> = Vec::new();
@@ -275,19 +283,24 @@ impl DFA {
 
         let start_state = 0usize;
         dfa_states.push(State(start_state));
-        dfa_transitions.push(HashMap::new());
+
+        let mut transition_vector = Vec::with_capacity(128);
+        for _ in 0..128 {
+            transition_vector.push(None::<Transition>);
+        }
+        dfa_transitions.push(transition_vector);
+
         dfa_to_nfa_state_mapping.push(start_epi_closure.clone());
         dfa_to_accepted_nfa_state_mapping.push(None);
         l_nfa_states_to_dfa_mapping.insert(start_epi_closure, State(start_state));
         l_worklist.push(State(start_state));
 
         // Process and add all dfa states
         while let Some(dfa_state) = l_worklist.pop() {
-            let nfa_states: &Vec<(usize, crate::nfa::nfa::State)> =
-                dfa_to_nfa_state_mapping.get(dfa_state.0).unwrap();
+            // Take the immutable borrow into a local variable
+            let nfa_states = { dfa_to_nfa_state_mapping.get(dfa_state.0).unwrap().clone() };
 
-            // Check if this dfa state is an accept state
-            // Note: If any of the NFA states in this dfa state is an accept state, then this dfa state is an accept state
+            // Check if this DFA state is an accept state
             for (idx, nfa_state) in nfa_states.iter() {
                 if nfas.get(*idx).unwrap().get_accept() == *nfa_state {
                     dfa_to_accepted_nfa_state_mapping
@@ -300,68 +313,80 @@ impl DFA {
             }
 
             // Process the Move operation for all transitions in the NFA states set
-            // The map stores all the transitions given a symbol for all the NFA states in the current dfa state
-            let mut move_transitions_symbol_to_transitions_map = HashMap::new();
+            let mut move_transitions_symbol_to_transitions_vec = vec![Vec::new(); 128];
             for (idx, nfa_state) in nfa_states.iter() {
-                let transitions: Option<&Vec<crate::nfa::nfa::Transition>> = nfas
+                let transitions = nfas
                     .get(*idx)
                     .unwrap()
                     .get_transitions_from_state(nfa_state);
                 for transition in transitions.into_iter().flatten() {
                     let symbol_onehot_encoding = transition.get_symbol_onehot_encoding();
 
-                    //We don't want to track epsilon transitions
-                    if symbol_onehot_encoding != 0 {
-                        move_transitions_symbol_to_transitions_map
-                            .entry(symbol_onehot_encoding)
-                            .or_insert_with(Vec::new)
-                            .push((idx.clone(), transition));
+                    for i in 0..128 {
+                        // We don't want to track epsilon transitions
+                        if (symbol_onehot_encoding & (1 << i)) != 0 {
+                            move_transitions_symbol_to_transitions_vec
+                                .get_mut(i)
+                                .unwrap()
+                                .push((idx, transition));
+                        }
                     }
                 }
             }
 
             // Process the Epsilon Closure of the Move operation
-            for (symbol_onehot_encoding, transitions) in
-                move_transitions_symbol_to_transitions_map.iter()
+            for (symbol, transitions) in move_transitions_symbol_to_transitions_vec
+                .iter()
+                .enumerate()
             {
+                if transitions.is_empty() {
+                    continue;
+                }
+
                 // Collect all the destination NFA states
-                let mut destination_nfa_states: Vec<(usize, crate::nfa::nfa::State)> = Vec::new();
+                let mut destination_nfa_states = Vec::new();
                 for (idx, transition) in transitions.iter() {
-                    destination_nfa_states.push((*idx, (**transition).get_to_state()));
+                    destination_nfa_states.push((**idx, (**transition).get_to_state()));
                 }
                 let destination_nfa_states =
                     Rc::new(DFA::epsilon_closure(&nfas, &destination_nfa_states));
 
-                // Check if the destination NFA states are already in the dfa states set
-                // let destination_dfa_state = DFA::combine_state_names(&destination_nfa_states);
+                // Check if the destination NFA states are already in the DFA states set
                 if !l_nfa_states_to_dfa_mapping.contains_key(&destination_nfa_states) {
-                    // We need to add a new state to the DFA
+                    // Add a new state to the DFA
                     let destination_dfa_state_idx = dfa_states.len();
 
                     dfa_states.push(State(destination_dfa_state_idx));
-                    dfa_transitions.push(HashMap::new());
+                    let mut transition_vector = Vec::new();
+                    for _ in 0..128 {
+                        transition_vector.push(None::<Transition>);
+                    }
+                    dfa_transitions.push(transition_vector);
                     dfa_to_accepted_nfa_state_mapping.push(None);
+
+                    // Ensure no mutable and immutable borrow overlap
                     dfa_to_nfa_state_mapping.push(destination_nfa_states.clone());
                     l_nfa_states_to_dfa_mapping.insert(
                         destination_nfa_states.clone(),
                         State(destination_dfa_state_idx),
                     );
                     l_worklist.push(State(destination_dfa_state_idx));
                 }
+
                 let destination_dfa_state = l_nfa_states_to_dfa_mapping
                     .get(&destination_nfa_states)
                     .unwrap();
 
-                // Add the transition to the dfa
-                dfa_transitions.get_mut(dfa_state.0).unwrap().insert(
-                    *symbol_onehot_encoding,
-                    Transition {
-                        from_state: dfa_state.clone(),
-                        symbol_onehot_encoding: *symbol_onehot_encoding,
-                        to_state: destination_dfa_state.clone(),
-                        tag: None,
-                    },
-                );
+                // Add the transition to the DFA
+                dfa_transitions.get_mut(dfa_state.0).unwrap()[symbol] = Some(Transition {
+                    from_state: dfa_state.clone(),
+                    symbol_onehot_encoding:
+                        crate::nfa::nfa::Transition::convert_char_to_symbol_onehot_encoding(
+                            symbol as u8 as char,
+                        ),
+                    to_state: destination_dfa_state.clone(),
+                    tag: None,
+                });
             }
         }
 
@@ -437,7 +462,11 @@ mod tests {
         let mut dfa = DFA::new();
 
         dfa.states.push(accept.clone());
-        dfa.transitions.push(HashMap::new());
+        let mut accept_transition_vec = Vec::new();
+        for _ in 0..128 {
+            accept_transition_vec.push(None);
+        }
+        dfa.transitions.push(accept_transition_vec);
         dfa.accept.push(accept.clone());
 
         dfa.add_transition(
@@ -497,6 +526,8 @@ mod tests {
         let nfa = create_nfa1()?;
         let dfa = DFA::from_multiple_nfas(vec![nfa]);
 
+        print!("{:?}", dfa);
+
         assert_eq!(dfa.start, dfa::dfa::State(0));
         assert_eq!(dfa.accept.len(), 2);
         assert_eq!(dfa.accept.contains(&State(1)), true);
@@ -509,18 +540,32 @@ mod tests {
         //
         assert_eq!(dfa.transitions.len(), 3);
         let transitions_from_start = dfa.transitions.get(0).unwrap();
-        assert_eq!(transitions_from_start.len(), 1);
-        let transitions_from_start_given_a = transitions_from_start
-            .get(&nfa::nfa::Transition::convert_char_to_symbol_onehot_encoding('a'))
-            .unwrap();
-        assert_eq!(transitions_from_start_given_a.to_state, State(1));
+        let mut valid_transitions_count = 0;
+        for transition in transitions_from_start.iter() {
+            if transition.is_some() {
+                valid_transitions_count += 1;
+            }
+        }
+        assert_eq!(valid_transitions_count, 1);
+        let transitions_from_start_given_a = transitions_from_start.get('a' as usize).unwrap();
+        assert_eq!(
+            transitions_from_start_given_a.as_ref().unwrap().to_state,
+            State(1)
+        );
 
         let transitions_to_accept = dfa.transitions.get(1).unwrap();
-        assert_eq!(transitions_to_accept.len(), 1);
-        let transitions_to_accept_given_b = transitions_to_accept
-            .get(&nfa::nfa::Transition::convert_char_to_symbol_onehot_encoding('b'))
-            .unwrap();
-        assert_eq!(transitions_to_accept_given_b.to_state, State(2));
+        let mut valid_transitions_count = 0;
+        for transition in transitions_to_accept.iter() {
+            if transition.is_some() {
+                valid_transitions_count += 1;
+            }
+        }
+        assert_eq!(valid_transitions_count, 1);
+        let transitions_to_accept_given_b = transitions_to_accept.get('b' as usize).unwrap();
+        assert_eq!(
+            transitions_to_accept_given_b.as_ref().unwrap().to_state,
+            State(2)
+        );
 
         // Check correctness given some examples
         assert_eq!(dfa.simulate("a"), (Some(0usize), true));
@@ -731,7 +776,7 @@ mod tests {
     #[test]
     fn test_timestamp() -> Result<()> {
         let mut parser = RegexParser::new();
-        let parsed_ast = parser.parse_into_ast(r"\d{4}\-\d{2}\-\d{2}T\d{2}:\d{2}:\d{2}\.\d{3}")?;
+        let parsed_ast = parser.parse_into_ast(r"\d{4}\-\d{2}\-\d{2}T\d{2}:\d{2}:\d{2}\.\d{2}")?;
 
         let mut nfa = NFA::new();
         nfa.add_ast_to_nfa(&parsed_ast, NFA::START_STATE, NFA::ACCEPT_STATE)?;
@@ -758,6 +803,7 @@ mod tests {
         println!("{:?}", dfa);
 
         assert_eq!(dfa.simulate("TIMESTAMP"), (Some(0usize), true));
+        assert_eq!(dfa.simulate("This log "), (None, false));
 
         Ok(())
     }