add comm

Makefile

@@ -5,6 +5,7 @@ PROGS       := \
   base64 \
   basename \
   cat \
+  comm \
   dirname \
   echo \
   env \

README.md

@@ -76,7 +76,6 @@ To do
 - chown
 - chroot
 - cksum
-- comm
 - copy
 - cp-hash
 - cp (some work done in ```dev``` branch)

comm/comm.rs

@@ -0,0 +1,115 @@
+#![crate_id(name="comm", vers="1.0.0", author="Michael Gehring")]
+
+/*
+ * This file is part of the uutils coreutils package.
+ *
+ * (c) Michael Gehring <mg@ebfe.org>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+extern crate getopts;
+
+use std::cmp::TotalOrd;
+use std::io::{BufferedReader, IoResult, print};
+use std::io::fs::File;
+use std::io::stdio::stdin;
+use std::os;
+use std::path::Path;
+
+static NAME : &'static str = "comm";
+static VERSION : &'static str = "1.0.0";
+
+fn delim(col: int, opts: &getopts::Matches) -> ~str {
+    let mut s = StrBuf::new();
+
+    if col > 1 && !opts.opt_present("1") {
+        s.push_str("\t");
+    }
+    if col > 2 && !opts.opt_present("2") {
+        s.push_str("\t");
+    }
+
+    s.to_owned()
+}
+
+fn comm(a: &mut Box<Buffer>, b: &mut Box<Buffer>, opts: &getopts::Matches) {
+
+    let mut ra = a.read_line();
+    let mut rb = b.read_line();
+
+    while ra.is_ok() || rb.is_ok() {
+        let ord = match (ra.clone(), rb.clone()) {
+            (Err(_), Ok(_))  => Greater,
+            (Ok(_) , Err(_)) => Less,
+            (Ok(s0), Ok(s1)) => s0.cmp(&s1),
+            _ => unreachable!(),
+        };
+
+        match ord {
+            Less => {
+                if !opts.opt_present("1") {
+                    print!("{}{}", delim(1, opts), ra.unwrap());
+                }
+                ra = a.read_line();
+            }
+            Greater => {
+                if !opts.opt_present("2") {
+                    print!("{}{}", delim(2, opts), rb.unwrap());
+                }
+                rb = b.read_line();
+            }
+            Equal => {
+                if !opts.opt_present("3") {
+                    print!("{}{}", delim(3, opts), ra.unwrap());
+                }
+                ra = a.read_line();
+                rb = b.read_line();
+            }
+        }
+    }
+}
+
+fn open_file(name: &str) -> IoResult<Box<Buffer>> {
+    match name {
+        "-" => Ok(box stdin() as Box<Buffer>),
+        _   => {
+            let f = try!(File::open(&Path::new(name)));
+            Ok(box BufferedReader::new(f) as Box<Buffer>)
+        }
+    }
+}
+
+pub fn main() {
+    let opts = [
+        getopts::optflag("1", "", "suppress column 1 (lines uniq to FILE1)"),
+        getopts::optflag("2", "", "suppress column 2 (lines uniq to FILE2)"),
+        getopts::optflag("3", "", "suppress column 3 (lines that appear in both files)"),
+        getopts::optflag("h", "help", "display this help and exit"),
+    ];
+
+    let matches = match getopts::getopts(os::args().tail(), opts) {
+        Ok(m) => m,
+        Err(err) => fail!("{}", err.to_err_msg()),
+    };
+
+    if matches.opt_present("help") || matches.free.len() != 2 {
+        println!("{} {}", NAME, VERSION);
+        println!("");
+        println!("Usage:");
+        println!("  {} [OPTIONS] FILE1 FILE2", NAME);
+        println!("");
+        print(getopts::usage("Compare sorted files line by line.", opts.as_slice()));
+        if matches.free.len() != 2 {
+            os::set_exit_status(1);
+        }
+        return;
+    }
+
+
+    let mut f1 = open_file(matches.free.get(0).clone()).unwrap();
+    let mut f2 = open_file(matches.free.get(1).clone()).unwrap();
+
+    comm(&mut f1, &mut f2, &matches)
+}