From 4aa01762e67317d7191fd12159caa83d2ca7f128 Mon Sep 17 00:00:00 2001
From: Wynd <wyndmaster@gmail.com>
Date: Sun, 20 Oct 2024 00:40:01 +0300
Subject: [PATCH] First attempt at a dumb brainfuck interpreter

---
 .gitignore           |  1 +
 Cargo.lock           |  7 ++++
 Cargo.toml           |  6 ++++
 input/cat.bf         |  1 +
 input/hello-world.bf |  2 ++
 input/loop.bf        |  1 +
 input/math.bf        |  1 +
 rust-toolchain.toml  |  2 ++
 src/main.rs          | 86 ++++++++++++++++++++++++++++++++++++++++++++
 9 files changed, 107 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 Cargo.lock
 create mode 100644 Cargo.toml
 create mode 100644 input/cat.bf
 create mode 100644 input/hello-world.bf
 create mode 100644 input/loop.bf
 create mode 100644 input/math.bf
 create mode 100644 rust-toolchain.toml
 create mode 100644 src/main.rs

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..ea8c4bf
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+/target
diff --git a/Cargo.lock b/Cargo.lock
new file mode 100644
index 0000000..c3c47f3
--- /dev/null
+++ b/Cargo.lock
@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "bfin"
+version = "0.1.0"
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..db62cc1
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "bfin"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
diff --git a/input/cat.bf b/input/cat.bf
new file mode 100644
index 0000000..05b49e2
--- /dev/null
+++ b/input/cat.bf
@@ -0,0 +1 @@
+,[.,]
diff --git a/input/hello-world.bf b/input/hello-world.bf
new file mode 100644
index 0000000..281a0a5
--- /dev/null
+++ b/input/hello-world.bf
@@ -0,0 +1,2 @@
++++++++++++[>++++++>+++++++++>++++++++>++++>+++>+<<<<<<-]>+++
++++.>++.+++++++..+++.>>.>-.<<-.<.+++.------.--------.>>>+.>-.
diff --git a/input/loop.bf b/input/loop.bf
new file mode 100644
index 0000000..dc6dbda
--- /dev/null
+++ b/input/loop.bf
@@ -0,0 +1 @@
+,[->+<]>++.
diff --git a/input/math.bf b/input/math.bf
new file mode 100644
index 0000000..ad6a80d
--- /dev/null
+++ b/input/math.bf
@@ -0,0 +1 @@
+,++.
diff --git a/rust-toolchain.toml b/rust-toolchain.toml
new file mode 100644
index 0000000..5d56faf
--- /dev/null
+++ b/rust-toolchain.toml
@@ -0,0 +1,2 @@
+[toolchain]
+channel = "nightly"
diff --git a/src/main.rs b/src/main.rs
new file mode 100644
index 0000000..f31df9f
--- /dev/null
+++ b/src/main.rs
@@ -0,0 +1,86 @@
+use std::{
+    collections::{HashMap, VecDeque},
+    fs,
+    io::{self, Write},
+    path::PathBuf,
+};
+
+const PROGRAM: &str = "hello-world.bf";
+
+fn main() {
+    let program: Vec<u8> = load_program();
+
+    let mut tape: Vec<u8> = vec![0];
+    let mut cell_index: usize = 0;
+
+    let mut ip: usize = 0;
+    let mut user_input: Vec<u8> = vec![];
+
+    let mut table: HashMap<usize, usize> = HashMap::new();
+    let mut stack: VecDeque<usize> = VecDeque::new();
+    for (ip, instruction) in program.iter().enumerate() {
+        if *instruction == b'[' {
+            stack.push_back(ip);
+        } else if *instruction == b']' {
+            let begin_index = stack.pop_front().unwrap();
+            table.insert(begin_index, ip);
+            table.insert(ip, begin_index);
+        }
+    }
+
+    while ip < program.len() {
+        let Some(instruction) = program.get(ip) else {
+            break;
+        };
+
+        match instruction {
+            b'+' => tape[cell_index] = tape[cell_index].wrapping_add(1),
+            b'-' => tape[cell_index] = tape[cell_index].wrapping_sub(1),
+            b'>' => {
+                cell_index = cell_index.wrapping_add(1);
+                if tape.len() <= cell_index {
+                    tape.push(0);
+                }
+            }
+            b'<' => cell_index = cell_index.wrapping_sub(1),
+            b'.' => print!("{}", tape[cell_index] as char),
+            b',' => {
+                if user_input.is_empty() {
+                    user_input = input();
+                }
+                tape[cell_index] = user_input.remove(0);
+            }
+            b'[' => {
+                if tape[cell_index] == 0 {
+                    ip = *table.get(&ip).unwrap();
+                }
+            }
+            b']' => {
+                if tape[cell_index] != 0 {
+                    ip = *table.get(&ip).unwrap();
+                }
+            }
+            _ => {}
+        }
+
+        ip += 1;
+    }
+
+    println!();
+}
+
+fn input() -> Vec<u8> {
+    let mut input = String::new();
+
+    print!("Input: ");
+    let _ = io::stdout().flush();
+    let _ = io::stdin().read_line(&mut input);
+
+    input.as_bytes().to_vec()
+}
+
+fn load_program() -> Vec<u8> {
+    let path: PathBuf = [".", "input", PROGRAM].iter().collect();
+    let input = fs::read_to_string(path).unwrap();
+    input.as_bytes().to_vec()
+}