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mod memory; pub use memory::BrainfuckTape; use std::{fmt, ops::Not}; #[derive(Debug, PartialEq, Clone, Copy)] pub enum BfOpKind { InvalidOp, IncPtr, DecPtr, IncData, DecData, ReadStdin, WriteStdout, LoopSetToZero, LoopMovePtr, LoopMoveData, JumpIfDataZero, JumpIfDataNotZero, } impl BfOpKind { fn from_character(instruction: u8) -> BfOpKind { match instruction as char { '>' => BfOpKind::IncPtr, '<' => BfOpKind::DecPtr, '+' => BfOpKind::IncData, '-' => BfOpKind::DecData, ',' => BfOpKind::ReadStdin, '.' => BfOpKind::WriteStdout, '[' => BfOpKind::JumpIfDataZero, ']' => BfOpKind::JumpIfDataNotZero, _ => BfOpKind::InvalidOp, } } } impl Not for BfOpKind { type Output = BfOpKind; fn not(self) -> Self { match self { BfOpKind::IncData => BfOpKind::DecData, BfOpKind::DecData => BfOpKind::IncData, BfOpKind::DecPtr => BfOpKind::IncPtr, BfOpKind::IncPtr => BfOpKind::DecPtr, kind => kind, } } } pub struct BfOp { kind: BfOpKind, argument: isize, } impl fmt::Debug for BfOp { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { f.write_str(format!("{} {:?}", self.argument, self.kind).as_str()) } } impl PartialEq for BfOp { fn eq(&self, other: &Self) -> bool { self.kind == other.kind } } fn optimize_loop(ops: &Vec<BfOp>, loop_start: isize) -> Vec<BfOp> { let mut new_ops: Vec<BfOp> = Vec::new(); if ops.len() as isize - loop_start == 2 { let repeated_op = &ops[loop_start as usize + 1]; if repeated_op.kind == BfOpKind::IncData || repeated_op.kind == BfOpKind::DecData { new_ops.push(BfOp { kind: BfOpKind::LoopSetToZero, argument: 0, }); } else if repeated_op.kind == BfOpKind::IncPtr { new_ops.push(BfOp { kind: BfOpKind::LoopMovePtr, argument: repeated_op.argument, }); } else if repeated_op.kind == BfOpKind::DecPtr { new_ops.push(BfOp { kind: BfOpKind::LoopMovePtr, argument: -repeated_op.argument, }); } else if ops.len() as isize - loop_start == 5 { if ops[loop_start as usize + 1].kind == BfOpKind::DecData && ops[loop_start as usize + 3].kind == BfOpKind::IncData && ops[loop_start as usize + 1].argument == 1 && ops[loop_start as usize + 3].argument == 1 { if ops[loop_start as usize + 2].kind == BfOpKind::IncPtr && ops[loop_start as usize + 4].kind == BfOpKind::DecPtr && ops[loop_start as usize + 2].argument == ops[loop_start as usize + 4].argument { new_ops.push(BfOp { kind: BfOpKind::LoopMoveData, argument: ops[loop_start as usize + 2].argument, }); } else if ops[loop_start as usize + 2].kind == BfOpKind::DecPtr && ops[loop_start as usize + 4].kind == BfOpKind::IncPtr && ops[loop_start as usize + 2].argument == ops[loop_start as usize + 4].argument { new_ops.push(BfOp { kind: BfOpKind::LoopMoveData, argument: -ops[loop_start as usize + 2].argument, }); } } } } new_ops } pub fn parse_bytes(code: &Vec<u8>) -> Vec<BfOp> { let mut ptr = 0; let code_size = code.len(); let mut ops = Vec::new(); let mut open_bracket_stack: Vec<isize> = Vec::new(); while ptr < code_size { let instruction = code[ptr]; if instruction == '[' as u8 { open_bracket_stack.push(ops.len() as isize); ops.push(BfOp { kind: BfOpKind::JumpIfDataZero, argument: -1, }); ptr += 1; } else if instruction == ']' as u8 { if !open_bracket_stack.is_empty() { let open_bracket_offset = open_bracket_stack[open_bracket_stack.len() - 1]; open_bracket_stack.pop(); let mut optimized_loop = optimize_loop(&ops, open_bracket_offset); if optimized_loop.is_empty() { ops[open_bracket_offset as usize].argument = ops.len() as isize; ops.push(BfOp { kind: BfOpKind::JumpIfDataNotZero, argument: open_bracket_offset, }); } else { let ops_len: usize = ops.len(); ops.drain(open_bracket_offset as usize..ops_len); ops.append(&mut optimized_loop); } ptr += 1; } } else { let mut kind = BfOpKind::from_character(instruction); let mut count: isize = 1; loop { ptr += 1; if ptr >= code_size { break; } let next_kind = BfOpKind::from_character(code[ptr]); if next_kind == BfOpKind::InvalidOp { continue; } else if next_kind == kind { count += 1; } else if next_kind == !kind { count -= 1; } else { break; } } if count < 0 { count = count.abs(); kind = !kind; } if count > 0 { match kind { BfOpKind::InvalidOp => {} BfOpKind::IncData | BfOpKind::DecData => { ops.push(BfOp { kind: kind, argument: count % 256, }); } _ => ops.push(BfOp { kind: kind, argument: count, }), } } } } ops } pub fn parse(s: String) -> Vec<BfOp> { parse_bytes(&s.into_bytes()) } pub fn execute( ops: Vec<BfOp>, mut input: impl FnMut() -> u8, mut output: impl FnMut(u8), should_stop: impl Fn(u128) -> bool, ) -> u128 { let mut ticks: u128 = 0; let mut code_ptr: usize = 0; let mut data = BrainfuckTape::new(); while code_ptr < ops.len() && !should_stop(ticks) { let op = &ops[code_ptr]; let kind = &op.kind; match kind { &BfOpKind::IncPtr => data.increase_pointer(op.argument), &BfOpKind::DecPtr => data.decrease_pointer(op.argument), &BfOpKind::IncData => data.increase_cell(op.argument as u8), &BfOpKind::DecData => data.decrease_cell(op.argument as u8), &BfOpKind::ReadStdin => { for _ in 0..op.argument { data.set_cell(input()); } } &BfOpKind::WriteStdout => { for _ in 0..op.argument { output(data.get_cell()); } } &BfOpKind::LoopSetToZero => data.set_cell(0), &BfOpKind::LoopMovePtr => { while data.get_cell() != 0 { data.move_ptr(op.argument); } } &BfOpKind::LoopMoveData => data.move_data(op.argument), &BfOpKind::JumpIfDataZero => { if data.get_cell() == 0 && op.argument >= 0 { code_ptr = op.argument as usize; } } &BfOpKind::JumpIfDataNotZero => { if data.get_cell() != 0 && op.argument >= 0 { code_ptr = op.argument as usize; } } &BfOpKind::InvalidOp => {} } code_ptr += 1; ticks += 1; } ticks }