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change transition from taking a char to taking an one-hot encoding u128
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@Louis-He
Louis-He committed Dec 8, 2024
1 parent effcc57 commit add4897
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Showing 2 changed files with 100 additions and 50 deletions.
105 changes: 67 additions & 38 deletions src/dfa/dfa.rs
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Original file line number Diff line number Diff line change
@@ -1,7 +1,6 @@
use crate::nfa::nfa::NFA;
use std::collections::{HashMap, HashSet};
use std::hash::Hash;
use std::process::id;

#[derive(Clone, Debug, Eq, Hash, PartialEq)]
struct State(String);
Expand All @@ -13,7 +12,7 @@ enum Tag {

struct Transition {
from_state: State,
symbol: char,
symbol_onehot_encoding: u128,
to_state: State,
tag: Option<Tag>,
}
Expand All @@ -22,7 +21,7 @@ pub(crate) struct DFA {
start: State,
accept: Vec<State>,
states: HashSet<State>,
transitions: HashMap<State, HashMap<char, Transition>>, // from_state -> symbol -> to_state
transitions: HashMap<State, HashMap<u128, Transition>>, // from_state -> symbol -> to_state
dfa_to_accepted_nfa_state_mapping: Option<HashMap<State, Vec<(usize, crate::nfa::nfa::State)>>>, // to determine which NFA gets matched
}

Expand All @@ -46,7 +45,7 @@ impl DFA {
fn add_transition(
&mut self,
from_state: State,
symbol: char,
symbol_onehot_encoding: u128,
to_state: State,
tag: Option<Tag>,
) {
Expand All @@ -56,16 +55,29 @@ impl DFA {
.entry(from_state.clone())
.or_insert_with(HashMap::new)
.insert(
symbol,
symbol_onehot_encoding,
Transition {
from_state,
symbol,
symbol_onehot_encoding,
to_state,
tag,
},
);
}

fn get_transition(
transitions_map: &HashMap<u128, Transition>,
symbol: char,
) -> Option<&Transition> {
for (transition_symbol, transition) in transitions_map.iter() {
if (*transition_symbol & (1 << (symbol as u8))) != 0 {
return Some(transition);
}
}

None
}

fn simulate(&self, input: &str) -> (Option<HashSet<usize>>, bool) {
let mut current_state = self.start.clone();

Expand All @@ -76,7 +88,7 @@ impl DFA {
return (None, false);
}
let transitions = transitions.unwrap();
let transition = transitions.get(&symbol);
let transition = DFA::get_transition(transitions, symbol);
if transition.is_none() {
return (None, false);
}
Expand All @@ -99,7 +111,7 @@ impl DFA {
.unwrap();

let mut nfa_ids = HashSet::new();
for (nfa_id, state) in nfa_states.iter() {
for (nfa_id, _state) in nfa_states.iter() {
nfa_ids.insert(*nfa_id);
}

Expand Down Expand Up @@ -152,7 +164,7 @@ impl DFA {
let mut dfa_to_nfa_state_mapping: HashMap<State, Vec<crate::nfa::nfa::State>> =
HashMap::new();
let mut dfa_accept_states = HashSet::new();
let mut dfa_transitions: HashMap<State, HashMap<char, Transition>> = HashMap::new();
let mut dfa_transitions: HashMap<State, HashMap<u128, Transition>> = HashMap::new();
let mut worklist: Vec<State> = Vec::new();

// Start with the epsilon closure of the start state
Expand Down Expand Up @@ -183,20 +195,22 @@ impl DFA {
let transitions: Option<&Vec<crate::nfa::nfa::Transition>> =
nfa.get_transitions_from_state(nfa_state);
for transition in transitions.into_iter().flatten() {
let symbol = transition.get_symbol();
let symbol_onehot_encoding = transition.get_symbol_onehot_encoding();

//We don't want to track epsilon transitions
if let Some(s) = symbol {
if symbol_onehot_encoding != 0 {
move_transitions_symbol_to_transitions_map
.entry(s)
.entry(symbol_onehot_encoding)
.or_insert_with(Vec::new)
.push(transition);
}
}
}

// Process the Epsilon Closure of the Move operation
for (symbol, transitions) in move_transitions_symbol_to_transitions_map.iter() {
for (symbol_onehot_encoding, transitions) in
move_transitions_symbol_to_transitions_map.iter()
{
// Collect all the destination NFA states
let mut destination_nfa_states = Vec::new();
for transition in transitions.iter() {
Expand All @@ -219,10 +233,10 @@ impl DFA {
.entry(dfa_state.clone())
.or_insert_with(HashMap::new)
.insert(
*symbol,
*symbol_onehot_encoding,
Transition {
from_state: dfa_state.clone(),
symbol: *symbol,
symbol_onehot_encoding: *symbol_onehot_encoding,
to_state: State(destination_dfa_state.clone()),
tag: None,
},
Expand Down Expand Up @@ -252,7 +266,7 @@ impl DFA {
Vec<(usize, crate::nfa::nfa::State)>,
> = HashMap::new();
let mut dfa_accept_states = HashSet::new();
let mut dfa_transitions: HashMap<State, HashMap<char, Transition>> = HashMap::new();
let mut dfa_transitions: HashMap<State, HashMap<u128, Transition>> = HashMap::new();
let mut worklist: Vec<State> = Vec::new();

// Start with the epsilon closure of the start state
Expand Down Expand Up @@ -299,20 +313,22 @@ impl DFA {
.unwrap()
.get_transitions_from_state(nfa_state);
for transition in transitions.into_iter().flatten() {
let symbol = transition.get_symbol();
let symbol_onehot_encoding = transition.get_symbol_onehot_encoding();

//We don't want to track epsilon transitions
if let Some(s) = symbol {
if symbol_onehot_encoding != 0 {
move_transitions_symbol_to_transitions_map
.entry(s)
.entry(symbol_onehot_encoding)
.or_insert_with(Vec::new)
.push((idx.clone(), transition));
}
}
}

// Process the Epsilon Closure of the Move operation
for (symbol, transitions) in move_transitions_symbol_to_transitions_map.iter() {
for (symbol_onehot_encoding, transitions) in
move_transitions_symbol_to_transitions_map.iter()
{
// Collect all the destination NFA states
let mut destination_nfa_states: Vec<(usize, crate::nfa::nfa::State)> = Vec::new();
for (idx, transition) in transitions.iter() {
Expand All @@ -335,10 +351,10 @@ impl DFA {
.entry(dfa_state.clone())
.or_insert_with(HashMap::new)
.insert(
*symbol,
*symbol_onehot_encoding,
Transition {
from_state: dfa_state.clone(),
symbol: *symbol,
symbol_onehot_encoding: *symbol_onehot_encoding,
to_state: State(destination_dfa_state.clone()),
tag: None,
},
Expand All @@ -358,7 +374,6 @@ impl DFA {

#[cfg(test)]
mod tests {
use crate::dfa::dfa::Tag::Start;
use crate::dfa::dfa::{State, DFA};
use crate::nfa::nfa::NFA;
use crate::{dfa, nfa};
Expand All @@ -369,8 +384,18 @@ mod tests {
let start = dfa::dfa::State("0".parse().unwrap());
let accept = dfa::dfa::State("1".parse().unwrap());
let mut dfa = DFA::new(start.clone(), vec![accept.clone()]);
dfa.add_transition(start.clone(), 'a', accept.clone(), None);
dfa.add_transition(accept.clone(), 'b', start.clone(), None);
dfa.add_transition(
start.clone(),
nfa::nfa::Transition::convert_char_to_symbol_onehot_encoding('a'),
accept.clone(),
None,
);
dfa.add_transition(
accept.clone(),
nfa::nfa::Transition::convert_char_to_symbol_onehot_encoding('b'),
start.clone(),
None,
);

assert_eq!(dfa.simulate("ab"), (None, false));
assert_eq!(dfa.simulate("a"), (None, true));
Expand Down Expand Up @@ -404,21 +429,21 @@ mod tests {
nfa.test_extern_add_transition(nfa::nfa::Transition::new(
nfa::nfa::State(1),
nfa::nfa::State(3),
Option::from('a'),
nfa::nfa::Transition::convert_char_to_symbol_onehot_encoding('a'),
-1,
));

nfa.test_extern_add_transition(nfa::nfa::Transition::new(
nfa::nfa::State(2),
nfa::nfa::State(4),
Option::from('a'),
nfa::nfa::Transition::convert_char_to_symbol_onehot_encoding('a'),
-1,
));

nfa.test_extern_add_transition(nfa::nfa::Transition::new(
nfa::nfa::State(3),
nfa::nfa::State(5),
Option::from('b'),
nfa::nfa::Transition::convert_char_to_symbol_onehot_encoding('b'),
-1,
));

Expand Down Expand Up @@ -446,7 +471,7 @@ mod tests {
nfa.test_extern_add_transition(nfa::nfa::Transition::new(
nfa::nfa::State(1),
nfa::nfa::State(1),
Option::from('c'),
nfa::nfa::Transition::convert_char_to_symbol_onehot_encoding('c'),
-1,
));

Expand Down Expand Up @@ -475,25 +500,25 @@ mod tests {
nfa.test_extern_add_transition(nfa::nfa::Transition::new(
nfa::nfa::State(1),
nfa::nfa::State(2),
Option::from('c'),
nfa::nfa::Transition::convert_char_to_symbol_onehot_encoding('c'),
-1,
));
nfa.test_extern_add_transition(nfa::nfa::Transition::new(
nfa::nfa::State(2),
nfa::nfa::State(2),
Option::from('c'),
nfa::nfa::Transition::convert_char_to_symbol_onehot_encoding('c'),
-1,
));
nfa.test_extern_add_transition(nfa::nfa::Transition::new(
nfa::nfa::State(2),
nfa::nfa::State(3),
Option::from('a'),
nfa::nfa::Transition::convert_char_to_symbol_onehot_encoding('a'),
-1,
));
nfa.test_extern_add_transition(nfa::nfa::Transition::new(
nfa::nfa::State(3),
nfa::nfa::State(4),
Option::from('b'),
nfa::nfa::Transition::convert_char_to_symbol_onehot_encoding('b'),
-1,
));

Expand All @@ -502,7 +527,7 @@ mod tests {

#[test]
fn test_nfa1_from_nfa_to_dfa() {
let mut nfa = create_nfa1();
let nfa = create_nfa1();
let dfa = DFA::from_nfa(nfa);

assert_eq!(dfa.start, dfa::dfa::State("0,1,2".to_string()));
Expand All @@ -518,15 +543,19 @@ mod tests {
assert_eq!(dfa.transitions.len(), 2);
let transitions_from_start = dfa.transitions.get(&State("0,1,2".to_string())).unwrap();
assert_eq!(transitions_from_start.len(), 1);
let transitions_from_start_given_a = transitions_from_start.get(&'a').unwrap();
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("3,4,6".to_string())
);

let transitions_to_accept = dfa.transitions.get(&State("3,4,6".to_string())).unwrap();
assert_eq!(transitions_to_accept.len(), 1);
let transitions_to_accept_given_b = transitions_to_accept.get(&'b').unwrap();
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("5,6".to_string())
Expand All @@ -542,7 +571,7 @@ mod tests {

#[test]
fn test_nfa2_from_nfa_to_dfa() {
let mut nfa = create_nfa2();
let nfa = create_nfa2();
let dfa = DFA::from_nfa(nfa);

// Check correctness given some examples
Expand All @@ -557,7 +586,7 @@ mod tests {

#[test]
fn test_nfa3_from_nfa_to_dfa() {
let mut nfa = create_nfa3();
let nfa = create_nfa3();
let dfa = DFA::from_nfa(nfa);

// Check correctness given some examples
Expand Down
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