yabf_rs 0.1.2

A simple crate that can be used to embed Brainfuck programs into your Rust programs.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106

use crate::io::BfIO;

use super::{Instruction, Program, ProgramStatus};

/// A structure that stores everything related to the program.
pub struct BfInstance {
    pub mem_ptr: usize,
    pub mem: Vec<u8>,

    pub program: Program,
    pub io_buf: BfIO,
}

impl Default for BfInstance {
    fn default() -> Self {
        Self {
            mem_ptr: 0,
            mem: vec![0; 256],
            program: Program::default(),
            io_buf: BfIO::default(),
        }
    }
}

impl From<Program> for BfInstance {
    fn from(p: Program) -> Self {
        Self {
            program: p,
            ..Default::default()
        }
    }
}

impl BfInstance {
    /// Executes the current instruction and increases the program counter.
    /// If the program couldn't receive an input via `input_source`, the program counter won't increase.
    pub fn step<SOURCE, FLUSH>(
        &mut self,
        mut input_source: SOURCE,
        mut flush: FLUSH,
    ) -> ProgramStatus
    where
        SOURCE: FnMut() -> Option<char>,
        FLUSH: FnMut(&mut Vec<char>) -> Result<(), ()>,
    {
        let mut block = false;
        match self.program.current() {
            Instruction::Add => self.mem[self.mem_ptr] += 1,
            Instruction::Sub => self.mem[self.mem_ptr] -= 1,
            Instruction::Right => {
                self.mem_ptr += 1;
                if self.mem_ptr >= self.mem.len() {
                    self.mem_ptr = 0;
                }
            }
            Instruction::Left => {
                if self.mem_ptr == 0 {
                    self.mem_ptr = self.mem.len() - 1;
                } else {
                    self.mem_ptr -= 1;
                }
            }
            Instruction::Out => {
                self.io_buf.write_out(self.mem[self.mem_ptr] as char);
            }
            Instruction::In => match self.io_buf.read_in(&mut input_source, &mut flush) {
                Some(c) => self.mem[self.mem_ptr] = c as u8,
                None => block = true,
            },
            Instruction::LoopEnd(l) => {
                if self.mem[self.mem_ptr] > 0 {
                    self.program.counter = *l;
                }
            }
            Instruction::LoopStart(l) => {
                if self.mem[self.mem_ptr] == 0 {
                    self.program.counter = *l;
                }
            }
        };

        if !block {
            self.program.step()
        } else {
            ProgramStatus::Run
        }
    }

    /// Convenience function that handles stepping/flushing for you.
    /// Not recommended if you need to do extra operations between or during steps.
    pub fn run<SOURCE, FLUSH>(&mut self, mut input_source: SOURCE, mut flush: FLUSH)
    where
        SOURCE: FnMut() -> Option<char>,
        FLUSH: FnMut(&mut Vec<char>) -> Result<(), ()>,
    {
        loop {
            if let ProgramStatus::Exit = self.step(&mut input_source, &mut flush) {
                break;
            }
        }

        self.io_buf
            .flush(flush)
            .expect("Couldn't flush output buffer.");
    }
}