Add fold utility

Cargo.lock

@@ -222,8 +222,15 @@ dependencies = [
  "libc",
  "num_cpus",
  "termcolor",
+ "textwrap",
 ]
 
+[[package]]
+name = "smawk"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f67ad224767faa3c7d8b6d91985b78e70a1324408abcb1cfcc2be4c06bc06043"
+
 [[package]]
 name = "strsim"
 version = "0.10.0"
@@ -239,6 +246,15 @@ dependencies = [
  "winapi-util",
 ]
 
+[[package]]
+name = "textwrap"
+version = "0.16.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "222a222a5bfe1bba4a77b45ec488a741b3cb8872e5e499451fd7d0129c9c7c3d"
+dependencies = [
+ "smawk",
+]
+
 [[package]]
 name = "winapi"
 version = "0.3.9"

Cargo.toml

@@ -6,16 +6,17 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-atty = "0.2.14"
-clap = "4.0.29"
-clap_complete = "4.0.6"
-clap_complete_nushell = "0.1.8"
-clap_mangen = "0.2.5"
-data-encoding = "2.3.3"
+atty = "0.2"
+clap = "4.0"
+clap_complete = "4.0"
+clap_complete_nushell = "0.1"
+clap_mangen = "0.2"
+data-encoding = "2.3"
 hostname = { version = "0.3", features = ["set"] }
-libc = "0.2.139"
-num_cpus = "1.15.0"
-termcolor = "1.1.3"
+libc = "0.2"
+num_cpus = "1.15"
+termcolor = "1.1"
+textwrap = { version = "0.16", default-features = false, features = ["smawk"] }
 
 [profile.release]
 codegen-units = 1

README.md

@@ -17,11 +17,12 @@ code between applets, making for an overall smaller binary.
 
 ## Scope
 *Shitbox* does not aim to supply an entire system of utilities, but rather a
-a subset of the most common Unix shell utilities. Things which are out of scope
+subset of the most common Unix shell utilities. Things which are out of scope
 for the project include:
 - Shells
 - Network servers
 - Kernel module handling utilities
+- Anything requiring suid such as `su` or `sudo`
 The code aims to be portable across **Unix** variants, ie Linux and BSD, but not
 MacOS or Windows. Development occurs on Linux, so if your OS is more exotic then
 YMMV.

src/cmd/fold/mod.rs

@@ -0,0 +1,132 @@
+use super::Cmd;
+use clap::{value_parser, Arg, ArgAction, ArgMatches, Command};
+use std::{fs::File, io::{self, BufRead, BufReader}};
+use textwrap::{fill, wrap_algorithms::WrapAlgorithm};
+
+#[derive(Debug)]
+pub struct Fold {
+    name: &'static str,
+    path: Option<crate::Path>,
+}
+
+impl Default for Fold {
+    fn default() -> Self {
+        Self {
+            name: "fold",
+            path: Some(crate::Path::UsrBin),
+        }
+    }
+}
+
+impl Cmd for Fold {
+    fn name(&self) -> &str {
+        self.name
+    }
+
+    fn cli(&self) -> Command {
+        Command::new(self.name)
+            .about("Wrap each input line to fit in specified width")
+            .author("Nathan Fisher")
+            .after_long_help("With no FILE, or when FILE is -, read standard input")
+            .args([
+                Arg::new("FILE").help("The input file to use").num_args(0..),
+                Arg::new("BYTES")
+                    .help("Count bytes rather than columns")
+                    .short('b')
+                    .long("bytes")
+                    .action(ArgAction::SetTrue),
+                Arg::new("WORDS")
+                    .help("Break at spaces")
+                    .short('s')
+                    .long("spaces")
+                    .action(ArgAction::SetTrue),
+                Arg::new("OPTIMAL")
+                    .help("Optimal fit")
+                    .long_help(
+                        "Uses a look ahad algorithm to avoid unnecessarily short or long lines",
+                    )
+                    .short('o')
+                    .long("optimal")
+                    .action(ArgAction::SetTrue)
+                    .conflicts_with_all(["BYTES", "WORDS"]),
+                Arg::new("WIDTH")
+                    .help("Use width columns")
+                    .short('w')
+                    .long("width")
+                    .default_value("80")
+                    .num_args(1)
+                    .value_parser(value_parser!(usize)),
+            ])
+    }
+
+    fn run(&self, matches: Option<&ArgMatches>) -> Result<(), Box<dyn std::error::Error>> {
+        let Some(matches) = matches else {
+            return Err(Box::new(io::Error::new(io::ErrorKind::Other, "no input")));
+        };
+        let files = match matches.get_many::<String>("FILE") {
+            Some(c) => c.map(String::to_string).collect(),
+            None => vec!["-".to_string()],
+        };
+        for file in files {
+            if file.as_str() == "-" {
+                wrap_stdin(matches)?;
+            } else {
+                wrap_file(&file, matches)?;
+            }
+        }
+        if matches.get_flag("BYTES") {
+            println!();
+        }
+        Ok(())
+    }
+
+    fn path(&self) -> Option<crate::Path> {
+        self.path
+    }
+}
+
+fn wrap_line(line: &str, args: &ArgMatches) {
+    let width = args.get_one("WIDTH").map(|x| *x).unwrap_or(80);
+    if args.get_flag("OPTIMAL") {
+        let line = line.replace('\t', "    ");
+        let opts = textwrap::Options::new(width).wrap_algorithm(WrapAlgorithm::new_optimal_fit());
+        println!("{}", fill(line.trim_end(), opts));
+    } else if args.get_flag("WORDS") {
+        let line = line.replace('\t', "    ");
+        let opts = textwrap::Options::new(width).wrap_algorithm(WrapAlgorithm::FirstFit);
+        println!("{}", fill(line.trim_end(), opts));
+    } else if args.get_flag("BYTES") {
+        for (index, b) in line.as_bytes().iter().enumerate() {
+            if index % width == 0 {
+                println!();
+            }
+            print!("{}", *b as char);
+        }
+    } else {
+        let line = line
+            .chars()
+            .collect::<Vec<char>>()
+            .chunks(width)
+            .map(|c| c.iter().collect::<String>())
+            .collect::<Vec<String>>();
+        for line in &line {
+            println!("{}", line);
+        }
+    }
+}
+
+fn wrap_stdin(args: &ArgMatches) -> Result<(), io::Error> {
+    for line in io::stdin().lock().lines() {
+        wrap_line(&line?, args);
+    }
+    Ok(())
+}
+
+fn wrap_file(file: &str, args: &ArgMatches) -> Result<(), io::Error> {
+    let fd = File::open(file)?;
+    let buf = BufReader::new(fd);
+    for line in buf.lines() {
+        wrap_line(&line?, args);
+    }
+    Ok(())
+}

src/cmd/mod.rs

@@ -14,6 +14,7 @@ pub mod dirname;
 pub mod echo;
 pub mod factor;
 pub mod r#false;
+pub mod fold;
 mod getty;
 pub mod head;
 pub mod hostname;
@@ -35,7 +36,7 @@ pub mod yes;
 
 pub use {
     self::hostname::Hostname, base32::Base32, base64::Base64, basename::Basename,
-    bootstrap::Bootstrap, dirname::Dirname, echo::Echo, factor::Factor, head::Head,
+    bootstrap::Bootstrap, dirname::Dirname, echo::Echo, factor::Factor, fold::Fold, head::Head,
     mountpoint::Mountpoint, nologin::Nologin, nproc::Nproc, r#false::False, r#true::True, rev::Rev,
     shitbox::Shitbox, sleep::Sleep, yes::Yes,
 };
@@ -57,6 +58,7 @@ pub fn get(name: &str) -> Option<Box<dyn Cmd>> {
         "echo" => Some(Box::new(Echo::default())),
         "factor" => Some(Box::new(Factor::default())),
         "false" => Some(Box::new(False::default())),
+        "fold" => Some(Box::new(Fold::default())),
         "head" => Some(Box::new(Head::default())),
         "mountpoint" => Some(Box::new(Mountpoint::default())),
         "nologin" => Some(Box::new(Nologin::default())),
@@ -70,7 +72,7 @@ pub fn get(name: &str) -> Option<Box<dyn Cmd>> {
     }
 }
 
-pub static COMMANDS: [&'static str; 18] = [
+pub static COMMANDS: [&'static str; 19] = [
     "base32",
     "base64",
     "basename",
@@ -79,6 +81,7 @@ pub static COMMANDS: [&'static str; 18] = [
     "echo",
     "false",
     "factor",
+    "fold",
     "head",
     "hostname",
     "mountpoint",