AoC2019/src/intcode/mod.rs

mod ops;
mod icio;

pub use icio::{IntCodeIO, StdAdapter};

pub struct IntCode<I: IntCodeIO> {
    addr_ptr: usize,
    memory: Vec<isize>,
    running: bool,
    io: I
}

pub struct Value {
    value: isize,
    address: Option<usize>,
}

struct Op<I: IntCodeIO> {
    argc: u8,
    argv: Vec<Value>,
    function: OpCodeFn<I>,
}

enum ParamMode {
    Position,
    Imediate
}

type OpCodeFn<I> = fn(&mut IntCode<I>, &Vec<Value>);

impl ParamMode {
    fn from_int(mode: usize) -> Self {
        match mode {
            0 => ParamMode::Position,
            1 => ParamMode::Imediate,
            _ => panic!("Unknown parameter mode {}", mode)
        }
    }
}

impl IntCode<StdAdapter> {
    #[cfg(test)]
    pub fn from_vec(v: Vec<isize>) -> Self {
        Self::from_vec_io(v, StdAdapter)
    }

    pub fn from_str(s: &str) -> Self {
        Self::from_str_io(s, StdAdapter)
    }
}

impl<I: IntCodeIO> IntCode<I> {
    pub fn from_vec_io(v: Vec<isize>, io: I) -> Self {
        IntCode {
            memory: v,
            addr_ptr: 0,
            running: true,
            io
        }
    }

    pub fn from_str_io(s: &str, io: I) -> Self {
        Self::from_vec_io(s.trim().split(",").filter_map(|n| n.parse().ok()).collect(), io)
    }

    fn get_op_modes(&mut self) -> (u8, Vec<ParamMode>) {
        let code = self.read_next();
        let op = (code % 100) as u8;
        let mut modes = code / 100;
        let mut vmodes = Vec::new();

        while modes > 0 {
            vmodes.push(ParamMode::from_int(modes as usize % 10));
            modes = modes / 10;
        }
        (op, vmodes)
    }

    fn read_next(&mut self) -> isize {
        self.addr_ptr += 1;
        self.memory[self.addr_ptr - 1]
    }

    pub fn read(&self, address: usize) -> isize {
        self.memory[address]
    }

    pub fn write(&mut self, address: usize, value: isize) {
        self.memory[address] = value;
    }

    pub fn jump(&mut self, address: usize) {
        self.addr_ptr = address;
    }

    pub fn terminate(&mut self) {
        self.running = false;
    }

    pub fn run(&mut self) -> isize {
        while self.running {
            let op = Op::from_intcode(self);
            op.run(self);
        }

        self.read(0)
    }
}

impl<I: IntCodeIO> Op<I> {
    fn from_intcode(intcode: &mut IntCode<I>) -> Self {
        let (code, vmodes) = intcode.get_op_modes();
        let mut op = Op::from_code(code);
        for idx in 0..(op.argc) {
            let code = intcode.read_next();
            let arg = match vmodes.get(idx as usize).unwrap_or(&ParamMode::Position) {
                ParamMode::Position => {
                    let value = intcode.read(code as usize);
                    Value { address: Some(code as usize), value }
                },
                ParamMode::Imediate => Value { address: None, value: code }
            };
            op.argv.push(arg);
        }
        op
    }

    fn from_code(code: u8) -> Self {
        match code {
            1 => Self::new(3, ops::add),
            2 => Self::new(3, ops::mul),
            3 => Self::new(1, ops::cin),
            4 => Self::new(1, ops::cout),
            5 => Self::new(2, ops::jump_if_true),
            6 => Self::new(2, ops::jump_if_false),
            7 => Self::new(3, ops::lt),
            8 => Self::new(3, ops::eq),
            99 => Self::new(0, ops::exit),
            c => panic!("Unknown opcode {}", c)
        }
    }

    fn new(argc: u8, function: OpCodeFn<I>) -> Self {
        Op {
            argc,
            argv: Vec::new(),
            function,
        }
    }

    fn run(&self, mut intcode: &mut IntCode<I>) {
        (self.function)(&mut intcode, &self.argv)
    }
}


#[cfg(test)]
mod test {
    use super::*;

    #[test]
    fn test_run_intcode_position_mode() {
        let input1 = vec![1, 0, 0, 0, 99];
        let input2 = vec![2, 0, 5, 0, 99, 3];

        let mut intcode = IntCode::from_vec(input1);
        assert_eq!(intcode.run(), 2);
        intcode = IntCode::from_vec(input2);
        assert_eq!(intcode.run(), 6);
    }

    #[test]
    fn test_run_intcode_imediate_mode() {
        let input = vec![1002, 4, 3, 4, 33];

        let mut intcode = IntCode::from_vec(input);
        intcode.run();
        assert_eq!(99, intcode.memory[4]);
    }
}