commit 060e00daff6f600431229456c2c9a576b8a58307
Author: Geoff <berrygeoffroy@gmail.com>
Date:   Wed Aug 17 21:53:23 2022 +0200

    first commit

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..42fa8bb
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+/target
+*.bf
+Cargo.lock
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..e0d955b
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "brainfuck"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+clap = { version = "3.2.17", features = ["derive"] }
+atty = "0.2.14"
diff --git a/src/main.rs b/src/main.rs
new file mode 100644
index 0000000..f0170a0
--- /dev/null
+++ b/src/main.rs
@@ -0,0 +1,149 @@
+use clap::CommandFactory;
+use clap::Parser;
+use std::io::Write;
+use std::{path::PathBuf, io::{self, Read, BufReader, BufRead}};
+
+#[derive(Parser, Debug)]
+#[clap(author, version, about, long_about = None)]
+struct Args {
+    #[clap(value_parser, value_name = "FILE")]
+    file: Option<PathBuf>,
+
+    #[clap(short, long, action)]
+    interactive: bool,
+
+    #[clap(short, long, action)]
+    verbose: bool,
+}
+
+fn main() -> Result<(), io::Error> {
+    //clap magic
+    let args = Args::parse();
+    let mut cmd = Args::command();
+
+    let mut reader: Box<dyn BufRead> = match &args.file {
+        None => {
+            if atty::is(atty::Stream::Stdin) && !args.interactive {
+                //special case when there is no piped file
+                //and --interactive is not specified
+                //display the help and exit
+                cmd.print_help()?;
+                return Ok(());
+            }
+            Box::new(BufReader::new(io::stdin()))
+        },
+        Some(filepath) => Box::new(BufReader::new(std::fs::File::open(filepath)?))
+    };
+
+    //init
+    let actions = std::collections::HashSet::from(['>', '<', '+', '-', '.', ',', '[', ']']);
+    let mut memory = [0_u8; 30000];
+    let mut pointer = 0;
+    let mut instructions_str: String = "".into();
+    let mut i = 0; //instructions index
+
+    if args.interactive && args.file.is_some() {
+        reader.read_to_string(&mut instructions_str)?;
+        reader = Box::new(BufReader::new(io::stdin()));
+    } else if !args.interactive {
+        reader.read_to_string(&mut instructions_str)?;
+    } 
+
+    loop {
+        //filtering instructions to only contain brainfuck code (optimization)
+        let instructions = instructions_str.chars()
+            .filter(|c| actions.contains(c))
+            .collect::<Vec<char>>();
+
+        'reading_instructions: while i < instructions.len() {
+            match instructions[i] {
+                '>' => pointer += 1,
+                '<' => pointer -= 1,
+                '+' => memory[pointer] += 1,
+                '-' => memory[pointer] -= 1,
+                '.' => print!("{}", memory[pointer] as char),
+                ',' => {
+                    let mut input = "".into();
+                    print!("Enter input (one byte only): ");
+                    io::stdout().flush()?;
+                    let mut handle = io::stdin().lock();
+                    handle.read_line(&mut input)?;
+
+                    if input.len() > 0 {
+                        memory[pointer] = input.chars().nth(0).unwrap() as u8;
+                    }
+                },
+                '[' => 
+                    if memory[pointer] == 0 {
+                        let mut pile = 1;
+                        while i < instructions.len() && pile != 0 {
+                            i += 1;
+
+                            match instructions[i] {
+                                '[' => pile += 1,
+                                ']' => pile -= 1,
+                                _ => ()
+                            }
+                        }
+                    }
+                ']' => 
+                    if memory[pointer] != 0 {
+                        let mut pile = 1;
+                        while i > 0 {
+                            match instructions[i-1] {
+                                ']' => pile += 1,
+                                '[' => pile -= 1,
+                                _ => ()
+                            }
+
+                            if pile == 0 { break; }
+                            i -= 1;
+                        }
+                        continue 'reading_instructions;
+                    }
+                
+                _ => ()
+            }
+
+            i += 1;
+        }
+
+        if args.verbose || args.interactive {
+            print_mem(&memory);
+            println!("pointer: {} (0x{:02x})", &pointer, &memory[pointer]);
+            println!();
+        }
+
+        if !args.interactive { break; }
+        
+        print!("~ ");
+        io::stdout().flush()?;
+        reader.read_line(&mut instructions_str)?;
+    }
+
+    Ok(())
+}
+
+fn print_mem(memory: &[u8]) {
+    let mut i = 0;
+    let mut s = String::new();
+    let mut z_counter = 0;
+    let z_limit = 3;
+
+    while i < memory.len() {
+        if memory[i] == 0 {
+            z_counter += 1;
+        } else {
+            z_counter = 0;
+        }
+        if z_counter == z_limit {
+            s += ".. ";
+
+        } else if z_counter < z_limit {
+            s += &format!("{:02x} ", memory[i]);
+        }
+        i += 1;
+    }
+    println!();
+    println!("-- memory (hex) --\n{}", s);
+}