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use std::io::{BufReader, BufRead}; | |
use std::fs::File; | |
fn main() { | |
let program_file = "prog".to_string(); | |
let program: Vec<i64> = load_program(&program_file); | |
let mut machine = Machine { | |
prog_ptr: 0, | |
relative_base: 0, | |
program: program.clone(), | |
input: vec!(2), | |
output: vec!(), | |
state: MachineState::ReadyToRun | |
}; | |
machine.resume(); | |
println!("Output: {:?}", machine.output); | |
} | |
struct Machine { | |
prog_ptr: i64, | |
relative_base: i64, | |
program: Vec<i64>, | |
input: Vec<i64>, | |
output: Vec<i64>, | |
state: MachineState | |
} | |
#[derive(PartialEq)] | |
enum MachineState { | |
ReadyToRun, | |
WaitingForInput, | |
Terminated | |
} | |
enum InstructionResult { | |
Continue, | |
WaitForInput, | |
Invalid, | |
Exit | |
} | |
enum ParameterMode { | |
Position = 0, | |
Direct = 1, | |
Relative= 2 | |
} | |
impl Machine { | |
fn resume(&mut self) { | |
loop { | |
let a = self.run_one_instruction(); | |
match a { | |
InstructionResult::Continue => { self.state = MachineState::ReadyToRun }, | |
InstructionResult::WaitForInput => { self.state = MachineState::WaitingForInput; break; }, | |
InstructionResult::Exit => { self.state = MachineState::Terminated; break; }, | |
_ => panic!("Unexpected action."), | |
} | |
} | |
} | |
fn grow_storage_if_required(&mut self, location: i64) { | |
if location >= self.program.len() as i64 { | |
self.program.resize((location + 1) as usize, 0) | |
} | |
} | |
fn get(&mut self, location: i64) -> i64 { | |
self.grow_storage_if_required(location); | |
self.program[location as usize] | |
} | |
fn put(&mut self, location: i64, value: i64) { | |
self.grow_storage_if_required(location); | |
self.program[location as usize] = value; | |
} | |
fn next_cell(&mut self) -> i64 { | |
let ind = self.prog_ptr; | |
self.prog_ptr += 1; | |
self.get(ind) | |
} | |
fn get_parameter_value(&mut self, mode: i64) -> i64 { | |
let value = self.next_cell(); | |
if mode == ParameterMode::Position as i64 { | |
return self.get(value) | |
} else if mode == ParameterMode::Direct as i64 { | |
return value | |
} else if mode == ParameterMode::Relative as i64 { | |
return self.get(value + self.relative_base) | |
} else { | |
panic!("Unknown parameter mode: {}", mode) | |
} | |
} | |
fn get_storage_location(&mut self, mode: i64) -> i64 { | |
if mode == ParameterMode::Relative as i64 { | |
self.next_cell() + self.relative_base | |
} else { | |
self.next_cell() | |
} | |
} | |
const ADD: i64 = 1; | |
const MULT: i64 = 2; | |
const INPUT: i64 = 3; | |
const OUTPUT: i64 = 4; | |
const JUMP_TRUE: i64 = 5; | |
const JUMP_FALSE: i64 = 6; | |
const LESS_THAN: i64 = 7; | |
const EQUALS: i64 = 8; | |
const RELATIVE_BASE_OFFSET: i64 = 9; | |
const EXIT: i64 = 99; | |
fn run_one_instruction(&mut self) -> InstructionResult { | |
let saved_prog_ptr = self.prog_ptr; | |
let next_instruction_code = self.next_cell(); | |
let next_op_code = next_instruction_code % 100; | |
let mode_par_1 = (next_instruction_code / 100) % 10; | |
let mode_par_2 = (next_instruction_code / 1000) % 10; | |
let mode_par_3 = (next_instruction_code / 10000) % 10; | |
match next_op_code { | |
Machine::ADD => { | |
let t1 = self.get_parameter_value(mode_par_1); | |
let t2 = self.get_parameter_value(mode_par_2); | |
let store_at = self.get_storage_location(mode_par_3); | |
self.put(store_at, t1 + t2); | |
InstructionResult::Continue | |
}, | |
Machine::MULT => { | |
let f1 = self.get_parameter_value(mode_par_1); | |
let f2 = self.get_parameter_value(mode_par_2); | |
let store_at = self.get_storage_location(mode_par_3); | |
self.put(store_at, f1 * f2); | |
InstructionResult::Continue | |
}, | |
Machine::INPUT => { | |
if !self.input.is_empty() { | |
let store_at = self.get_storage_location(mode_par_1); | |
let c = self.input.remove(0); | |
self.put(store_at, c); | |
InstructionResult::Continue | |
} else { | |
self.prog_ptr = saved_prog_ptr; | |
InstructionResult::WaitForInput | |
} | |
}, | |
Machine::JUMP_TRUE => { | |
let value = self.get_parameter_value(mode_par_1); | |
let jump_target = self.get_parameter_value(mode_par_2); | |
if value != 0 { | |
self.prog_ptr = jump_target | |
} | |
InstructionResult::Continue | |
}, | |
Machine::JUMP_FALSE => { | |
let value = self.get_parameter_value(mode_par_1); | |
let jump_target = self.get_parameter_value(mode_par_2); | |
if value == 0 { | |
self.prog_ptr = jump_target | |
} | |
InstructionResult::Continue | |
}, | |
Machine::LESS_THAN => { | |
let p1 = self.get_parameter_value(mode_par_1); | |
let p2 = self.get_parameter_value(mode_par_2); | |
let store_at = self.get_storage_location(mode_par_3); | |
let result = if p1 < p2 { 1 } else { 0 }; | |
self.put(store_at, result); | |
InstructionResult::Continue | |
}, | |
Machine::EQUALS => { | |
let p1 = self.get_parameter_value(mode_par_1); | |
let p2 = self.get_parameter_value(mode_par_2); | |
let store_at = self.get_storage_location(mode_par_3); | |
let result = if p1 == p2 { 1 } else { 0 }; | |
self.put(store_at, result); | |
InstructionResult::Continue | |
}, | |
Machine::OUTPUT => { | |
let v = self.get_parameter_value(mode_par_1); | |
self.output.push(v); | |
InstructionResult::Continue | |
}, | |
Machine::RELATIVE_BASE_OFFSET => { | |
let v = self.get_parameter_value(mode_par_1); | |
self.relative_base += v; | |
InstructionResult::Continue | |
}, | |
Machine::EXIT => InstructionResult::Exit, | |
_ => InstructionResult::Invalid | |
} | |
} | |
} | |
fn load_program(program_file: &String) -> Vec<i64> { | |
let mut prog: Vec<i64> = vec![]; | |
let file = File::open(program_file).expect("Could not open program file!"); | |
let reader = BufReader::new(file); | |
let line = reader.lines().next().expect("Could not read from file"); | |
let line = line.expect("No string there."); | |
for s in line.split(",") { | |
let c = i64::from_str_radix(&s, 10).expect("Could not parse int"); | |
prog.push(c); | |
} | |
prog | |
} |
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