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use std::cmp::Ordering;
use std::fs::File;
use std::io::{self, stdin, BufRead, BufReader, Stdin};
use std::path::Path;
use uucore::error::FromIo;
use uucore::error::UResult;
use uucore::format_usage;
use clap::{crate_version, Arg, ArgMatches, Command};
static ABOUT: &str = "compare two sorted files line by line";
static LONG_HELP: &str = "";
const USAGE: &str = "{} [OPTION]... FILE1 FILE2";
mod options {
pub const COLUMN_1: &str = "1";
pub const COLUMN_2: &str = "2";
pub const COLUMN_3: &str = "3";
pub const DELIMITER: &str = "output-delimiter";
pub const DELIMITER_DEFAULT: &str = "\t";
pub const FILE_1: &str = "FILE1";
pub const FILE_2: &str = "FILE2";
}
fn mkdelim(col: usize, opts: &ArgMatches) -> String {
let mut s = String::new();
let delim = match opts.value_of(options::DELIMITER).unwrap() {
"" => "\0",
delim => delim,
};
if col > 1 && !opts.contains_id(options::COLUMN_1) {
s.push_str(delim.as_ref());
}
if col > 2 && !opts.contains_id(options::COLUMN_2) {
s.push_str(delim.as_ref());
}
s
}
fn ensure_nl(line: &mut String) {
if !line.ends_with('\n') {
line.push('\n');
}
}
enum LineReader {
Stdin(Stdin),
FileIn(BufReader<File>),
}
impl LineReader {
fn read_line(&mut self, buf: &mut String) -> io::Result<usize> {
match *self {
Self::Stdin(ref mut r) => r.read_line(buf),
Self::FileIn(ref mut r) => r.read_line(buf),
}
}
}
fn comm(a: &mut LineReader, b: &mut LineReader, opts: &ArgMatches) {
let delim: Vec<String> = (0..4).map(|col| mkdelim(col, opts)).collect();
let ra = &mut String::new();
let mut na = a.read_line(ra);
let rb = &mut String::new();
let mut nb = b.read_line(rb);
while na.is_ok() || nb.is_ok() {
let ord = match (na.is_ok(), nb.is_ok()) {
(false, true) => Ordering::Greater,
(true, false) => Ordering::Less,
(true, true) => match (&na, &nb) {
(&Ok(0), &Ok(0)) => break,
(&Ok(0), _) => Ordering::Greater,
(_, &Ok(0)) => Ordering::Less,
_ => ra.cmp(&rb),
},
_ => unreachable!(),
};
match ord {
Ordering::Less => {
if !opts.contains_id(options::COLUMN_1) {
ensure_nl(ra);
print!("{}{}", delim[1], ra);
}
ra.clear();
na = a.read_line(ra);
}
Ordering::Greater => {
if !opts.contains_id(options::COLUMN_2) {
ensure_nl(rb);
print!("{}{}", delim[2], rb);
}
rb.clear();
nb = b.read_line(rb);
}
Ordering::Equal => {
if !opts.contains_id(options::COLUMN_3) {
ensure_nl(ra);
print!("{}{}", delim[3], ra);
}
ra.clear();
rb.clear();
na = a.read_line(ra);
nb = b.read_line(rb);
}
}
}
}
fn open_file(name: &str) -> io::Result<LineReader> {
match name {
"-" => Ok(LineReader::Stdin(stdin())),
_ => {
let f = File::open(&Path::new(name))?;
Ok(LineReader::FileIn(BufReader::new(f)))
}
}
}
#[uucore::main]
pub fn uumain(args: impl uucore::Args) -> UResult<()> {
let args = args.collect_lossy();
let matches = uu_app().get_matches_from(args);
let filename1 = matches.value_of(options::FILE_1).unwrap();
let filename2 = matches.value_of(options::FILE_2).unwrap();
let mut f1 = open_file(filename1).map_err_context(|| filename1.to_string())?;
let mut f2 = open_file(filename2).map_err_context(|| filename2.to_string())?;
comm(&mut f1, &mut f2, &matches);
Ok(())
}
pub fn uu_app<'a>() -> Command<'a> {
Command::new(uucore::util_name())
.version(crate_version!())
.about(ABOUT)
.after_help(LONG_HELP)
.override_usage(format_usage(USAGE))
.infer_long_args(true)
.arg(
Arg::new(options::COLUMN_1)
.short('1')
.help("suppress column 1 (lines unique to FILE1)"),
)
.arg(
Arg::new(options::COLUMN_2)
.short('2')
.help("suppress column 2 (lines unique to FILE2)"),
)
.arg(
Arg::new(options::COLUMN_3)
.short('3')
.help("suppress column 3 (lines that appear in both files)"),
)
.arg(
Arg::new(options::DELIMITER)
.long(options::DELIMITER)
.help("separate columns with STR")
.value_name("STR")
.default_value(options::DELIMITER_DEFAULT)
.hide_default_value(true),
)
.arg(
Arg::new(options::FILE_1)
.required(true)
.value_hint(clap::ValueHint::FilePath),
)
.arg(
Arg::new(options::FILE_2)
.required(true)
.value_hint(clap::ValueHint::FilePath),
)
}
