Fixing irc log

README.md

Commands:

wget -O original.log url/to/raw
cargo build --release
target/release/fixlog original.log > fixed.log

Cargo.toml

[package]
name = "fixlog"
version = "0.1.0"
license = "MIT"
authors = ["Adit Cahya Ramadhan <[email protected]>"]

[[bin]]
name = "fixlog"
path = "main.rs"

[dependencies]
regex = "0.2.1"

main.rs

extern crate regex;

use regex::{Regex, Captures};
use std::io::Read;
use std::fs::File;
use std::env;

macro_rules! debug {
    ($($arg:tt)*) => {
        {
            use std::io::Write;
            let _ = writeln!(std::io::stderr(), $($arg)*);
        }
    }
}

fn replace_lines() {
    let re = Regex::new(
        r"(?xm)  # insignificant whitespace and multiline mode

            ^    # treated as the `start` of the line

                (?P<before>

                \[ # start with opening square bracket


                    # Date part

                    \d{4}           # year
                    -
                    \d{2}           # month
                    -
                ) # end of before named capture

                    (?P<day>\d{2})  # day

                    (?-x: )         # separated by space

                    # Time part

                    (?P<hour>\d{2}) # hour

                (?P<after>

                    :
                    \d{2}           # minutes
                    :
                    \d{2}           # seconds

                    (?-x: )

                    # Time zone part

                    [A-Z]+          # time zone abbrev

                \] # end of square bracket

                .* # and anything after that

                ) # end of `after` named capture

            $      # end of the line
        "
    ).expect("Regex error");


    let buffer = file_content();

    let mut total = 0;

    let mut prev: Option<(u8, u8)> = None;
    let mut hourtime = false;

    let result = re.replace_all(&buffer, |cap: &Captures| {

        total += 1;

        let day = cap.name("day").unwrap().as_str().parse().unwrap();
        let mut hour = cap.name("hour").unwrap().as_str().parse().unwrap();
        if prev > Some((day, hour)) {
            hour += 12;
        } else if let Some((prevday, _)) = prev {
            if (prevday + 1  == day || hourtime) && hour >= 12 {
                hourtime = true;
                hour -= 12;
            } else {
                hourtime = false;
            }
        }
        prev = Some((day, hour));

        let before = cap.name("before").unwrap().as_str();
        let after = cap.name("after").unwrap().as_str();

        format!("{before}{day:02} {hour:02}{after}",
                before=before,
                after=after,
                day=day,
                hour=hour
        )
    });

    debug!("Total lines: {}", total);
    print!("{}", result);
}

fn file_content() -> String {
    let filename = env::args().nth(1).expect("No filename supplied");
    debug!("Filename: {}", filename);

    let mut file = File::open(filename).expect("Can't open file");

    let mut buffer = String::new();
    file.read_to_string(&mut buffer).unwrap();
    buffer
}


fn main() {
    replace_lines();
}