Intcode program into lib! It's shared code now.

1 files changed, 246 insertions, 0 deletions

diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..2591a54
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,246 @@
+use rpds::{list::List, vector::Vector};
+use std::fmt;
+use std::iter;
+use std::iter::FromIterator;
+use std::iter::IntoIterator;
+
+pub type Intcode = i32;
+
+#[derive(Debug, Clone)]
+pub struct IntcodeProgram {
+    instruction_pointer: usize,
+    error: bool,
+    halted: bool,
+    memory: Vector<Intcode>,
+    input: List<Intcode>,
+    output: Vector<Intcode>,
+}
+
+impl FromIterator<Intcode> for IntcodeProgram {
+    fn from_iter<I: IntoIterator<Item = Intcode>>(iter: I) -> Self {
+        IntcodeProgram {
+            instruction_pointer: 0,
+            error: false,
+            halted: false,
+            memory: iter.into_iter().collect(),
+            input: List::new(),
+            output: Vector::new(),
+        }
+    }
+}
+
+impl IntcodeProgram {
+    pub fn with_noun_verb_input(&self, noun: Intcode, verb: Intcode) -> IntcodeProgram {
+        self.with_memory_set(1, noun).with_memory_set(2, verb)
+    }
+
+    pub fn with_input(&self, input: List<Intcode>) -> IntcodeProgram {
+        IntcodeProgram {
+            input,
+            ..self.clone()
+        }
+    }
+
+    pub fn execute(&self) -> Result<Vector<Intcode>, IntcodeProgramError> {
+        self.run_to_termination().output_into_result()
+    }
+
+    pub fn execute_returning_memory_0(&self) -> Result<Option<Intcode>, IntcodeProgramError> {
+        self.run_to_termination().memory_0_into_result()
+    }
+
+    fn with_instruction_pointer(&self, instruction_pointer: usize) -> IntcodeProgram {
+        IntcodeProgram {
+            instruction_pointer,
+            ..self.clone()
+        }
+    }
+
+    fn with_instruction_pointer_offset(&self, offset: usize) -> IntcodeProgram {
+        IntcodeProgram {
+            instruction_pointer: self.instruction_pointer + offset,
+            ..self.clone()
+        }
+    }
+
+    fn with_memory_set(&self, address: usize, value: Intcode) -> IntcodeProgram {
+        self.memory
+            .set(address, value)
+            .map(|memory| IntcodeProgram {
+                memory,
+                ..self.clone()
+            })
+            .unwrap_or(self.error())
+    }
+
+    fn with_input_consumed(&self) -> IntcodeProgram {
+        self.input
+            .drop_first()
+            .map(|input| IntcodeProgram {
+                input,
+                ..self.clone()
+            })
+            .unwrap_or(self.error())
+    }
+
+    fn with_output(&self, print: Intcode) -> IntcodeProgram {
+        IntcodeProgram {
+            output: self.output.push_back(print),
+            ..self.clone()
+        }
+    }
+
+    fn output_into_result(&self) -> Result<Vector<Intcode>, IntcodeProgramError> {
+        if self.error {
+            Err(IntcodeProgramError)
+        } else {
+            Ok(self.output.clone())
+        }
+    }
+
+    fn memory_0_into_result(&self) -> Result<Option<Intcode>, IntcodeProgramError> {
+        if self.error {
+            Err(IntcodeProgramError)
+        } else {
+            Ok(self.memory.get(0).cloned())
+        }
+    }
+
+    fn run_to_termination(&self) -> IntcodeProgram {
+        iter::successors(Some(self.clone()), |p| Some(IntcodeProgram::next(&p)))
+            .find(|p| p.halted)
+            .unwrap() // successors doesn't terminate, so this will never be none.
+    }
+
+    fn next(&self) -> IntcodeProgram {
+        //eprintln!("{:?}", self);
+        self.memory
+            .get(self.instruction_pointer)
+            .map(|&opcode| match opcode % 100 {
+                1 => self.add(opcode),
+                2 => self.multiply(opcode),
+                3 => self.input(opcode),
+                4 => self.output(opcode),
+                5 => self.jump_if_true(opcode),
+                6 => self.jump_if_false(opcode),
+                7 => self.less_than(opcode),
+                8 => self.equals(opcode),
+                99 => self.halt(),
+                _ => self.error(),
+            })
+            .unwrap_or(self.error())
+    }
+
+    fn add(&self, mode: Intcode) -> IntcodeProgram {
+        match (self.get(1, mode), self.get(2, mode), self.get_immediate(3)) {
+            (Some(in1), Some(in2), Some(out)) => self
+                .with_instruction_pointer_offset(4)
+                .with_memory_set(out as usize, in1 + in2),
+            _ => self.error(),
+        }
+    }
+
+    fn multiply(&self, mode: Intcode) -> IntcodeProgram {
+        match (self.get(1, mode), self.get(2, mode), self.get_immediate(3)) {
+            (Some(in1), Some(in2), Some(out)) => self
+                .with_instruction_pointer_offset(4)
+                .with_memory_set(out as usize, in1 * in2),
+            _ => self.error(),
+        }
+    }
+
+    fn input(&self, _mode: Intcode) -> IntcodeProgram {
+        match (self.input.first().cloned(), self.get_immediate(1)) {
+            (Some(input), Some(out)) => self
+                .with_instruction_pointer_offset(2)
+                .with_memory_set(out as usize, input)
+                .with_input_consumed(),
+            _ => self.error(),
+        }
+    }
+
+    fn output(&self, mode: Intcode) -> IntcodeProgram {
+        match self.get(1, mode) {
+            Some(print) => self.with_instruction_pointer_offset(2).with_output(print),
+            _ => self.error(),
+        }
+    }
+
+    fn jump_if_true(&self, mode: Intcode) -> IntcodeProgram {
+        match (self.get(1, mode), self.get(2, mode)) {
+            (Some(pred), Some(to)) if pred != 0 => self.with_instruction_pointer(to as usize),
+            (Some(_), Some(_)) => self.with_instruction_pointer_offset(3),
+            _ => self.error(),
+        }
+    }
+    fn jump_if_false(&self, mode: Intcode) -> IntcodeProgram {
+        match (self.get(1, mode), self.get(2, mode)) {
+            (Some(pred), Some(to)) if pred == 0 => self.with_instruction_pointer(to as usize),
+            (Some(_), Some(_)) => self.with_instruction_pointer_offset(3),
+            _ => self.error(),
+        }
+    }
+
+    fn less_than(&self, mode: Intcode) -> IntcodeProgram {
+        match (self.get(1, mode), self.get(2, mode), self.get_immediate(3)) {
+            (Some(in1), Some(in2), Some(out)) => self
+                .with_instruction_pointer_offset(4)
+                .with_memory_set(out as usize, if in1 < in2 { 1 } else { 0 }),
+            _ => self.error(),
+        }
+    }
+
+    fn equals(&self, mode: Intcode) -> IntcodeProgram {
+        match (self.get(1, mode), self.get(2, mode), self.get_immediate(3)) {
+            (Some(in1), Some(in2), Some(out)) => self
+                .with_instruction_pointer_offset(4)
+                .with_memory_set(out as usize, if in1 == in2 { 1 } else { 0 }),
+            _ => self.error(),
+        }
+    }
+
+    fn halt(&self) -> IntcodeProgram {
+        IntcodeProgram {
+            halted: true,
+            ..self.clone()
+        }
+    }
+
+    fn error(&self) -> IntcodeProgram {
+        IntcodeProgram {
+            halted: true,
+            error: true,
+            ..self.clone()
+        }
+    }
+
+    fn get(&self, pointer_offset: usize, mode: Intcode) -> Option<Intcode> {
+        match mode / (10 as Intcode).pow(pointer_offset as u32 + 1) % 10 {
+            0 => self.get_position(pointer_offset),
+            1 => self.get_immediate(pointer_offset),
+            _ => None,
+        }
+    }
+
+    fn get_immediate(&self, pointer_offset: usize) -> Option<Intcode> {
+        self.memory
+            .get(self.instruction_pointer + pointer_offset)
+            .cloned()
+    }
+
+    fn get_position(&self, pointer_offset: usize) -> Option<Intcode> {
+        self.get_immediate(pointer_offset)
+            .and_then(|r| self.memory.get(r as usize))
+            .cloned()
+    }
+}
+
+#[derive(Debug, PartialEq)]
+pub struct IntcodeProgramError;
+
+impl fmt::Display for IntcodeProgramError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "Unknown error")
+    }
+}
+impl std::error::Error for IntcodeProgramError {}