use alloc::{string::String, vec::Vec};
use core::marker::PhantomData;
use libafl_bolts::rands::Rand;
use serde::{Deserialize, Serialize};
use crate::{
generators::Generator,
inputs::{GramatronInput, Terminal},
state::HasRand,
Error,
};
#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Eq)]
pub struct Trigger {
pub dest: usize,
pub term: String,
}
#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Eq)]
pub struct Automaton {
pub final_state: usize,
pub init_state: usize,
pub pda: Vec<Vec<Trigger>>,
}
#[derive(Clone, Debug)]
pub struct GramatronGenerator<'a, S>
where
S: HasRand,
{
automaton: &'a Automaton,
phantom: PhantomData<S>,
}
impl<'a, S> Generator<GramatronInput, S> for GramatronGenerator<'a, S>
where
S: HasRand,
{
fn generate(&mut self, state: &mut S) -> Result<GramatronInput, Error> {
let mut input = GramatronInput::new(vec![]);
self.append_generated_terminals(&mut input, state);
Ok(input)
}
}
impl<'a, S> GramatronGenerator<'a, S>
where
S: HasRand,
{
#[must_use]
pub fn new(automaton: &'a Automaton) -> Self {
Self {
automaton,
phantom: PhantomData,
}
}
pub fn append_generated_terminals(&self, input: &mut GramatronInput, state: &mut S) -> usize {
let mut counter = 0;
let final_state = self.automaton.final_state;
let mut current_state =
input
.terminals()
.last()
.map_or(self.automaton.init_state, |last| {
let triggers = &self.automaton.pda[last.state];
let idx = state.rand_mut().below(triggers.len() as u64) as usize;
triggers[idx].dest
});
while current_state != final_state {
let triggers = &self.automaton.pda[current_state];
let idx = state.rand_mut().below(triggers.len() as u64) as usize;
let trigger = &triggers[idx];
input
.terminals_mut()
.push(Terminal::new(current_state, idx, trigger.term.clone()));
current_state = trigger.dest;
counter += 1;
}
counter
}
}