Add printable CLI to strip unwanted characters from email.

src/bin/mailparse.rs

@@ -0,0 +1,89 @@
+use std::env;
+use std::error::Error;
+use std::fs::File;
+use std::io::prelude::*;
+use std::process::exit;
+use std::slice::Iter;
+
+use mailparse::dateparse;
+use mailparse::MailHeaderMap;
+
+fn newline(b: &u8) -> bool {
+    *b == b'\n'
+}
+
+fn index_of(it: &mut Iter<u8>, needle: &[u8]) -> Option<usize> {
+    let mut needle_ix = 0;
+    it.position(move |&b| {
+        if b == needle[needle_ix] {
+            needle_ix += 1;
+            if needle_ix == needle.len() {
+                return true;
+            }
+        } else if b == needle[0] {
+            needle_ix = 1;
+        } else {
+            needle_ix = 0;
+        }
+        false
+    })
+}
+
+fn parse_mbox(mbox_bytes: &Vec<u8>) -> Result<(), Box<dyn Error>> {
+    let mut it = mbox_bytes.iter();
+    let mut ix = 0;
+
+    loop {
+        let mail_start = it.position(newline);
+        if mail_start.is_none() {
+            return Ok(());
+        }
+        ix += mail_start.unwrap() + 1;
+        let start = ix;
+
+        let delim = b"\nFrom ";
+        let next_mail_start = index_of(&mut it, delim);
+
+        let end = match next_mail_start {
+            Some(x) => {
+                ix += x + 1;
+                ix - delim.len()
+            }
+            None => mbox_bytes.len(),
+        };
+
+        let mail_bytes = &mbox_bytes[start..end];
+
+        let mail = mailparse::parse_mail(mail_bytes).unwrap();
+        println!(
+            "{:?} {:?} from {:?}",
+            match mail.headers.get_first_value("Date")? {
+                Some(date) => date,
+                None => "NO DATE".to_string(),
+            },
+            match mail.headers.get_first_value("Subject")? {
+                Some(subject) => subject,
+                None => "NO SUBJECT".to_string(),
+            },
+            match mail.headers.get_first_value("From")? {
+                Some(from) => from,
+                None => "NO FROM".to_string(),
+            },
+        );
+    }
+}
+
+fn main() {
+    if env::args().count() <= 1 {
+        println!("Provide mbox files as arguments");
+        exit(1);
+    }
+    let mut args = env::args();
+    args.next(); // drop executable name
+    args.for_each(|mbox_path| {
+        let mut mbox = File::open(mbox_path).unwrap();
+        let mut mails = Vec::new();
+        mbox.read_to_end(&mut mails).unwrap();
+        parse_mbox(&mails);
+    });
+}

src/bin/printable.rs

@@ -0,0 +1,27 @@
+use std::{io, io::Read};
+
+use regex::Regex;
+
+fn main() -> io::Result<()> {
+    let re = Regex::new("[^[[:print:]]\n]").expect("invalid regex");
+    let mut buffer = String::new();
+    io::stdin().read_to_string(&mut buffer)?;
+    let buffer = re.replace_all(&buffer, "");
+
+    let mut last_c = 0;
+    for l in buffer.lines() {
+        let c = l
+            .as_bytes()
+            .iter()
+            .filter(|b| match b {
+                b' ' | b'\t' => false,
+                _ => true,
+            })
+            .count();
+        if !(c == 0 && last_c == 0) {
+            println!("{l}");
+        }
+        last_c = c;
+    }
+    Ok(())
+}