From aa51311f83857b26e021f8c0e32f32e952161901 Mon Sep 17 00:00:00 2001
From: "T. Jameson Little" <t.jameson.little@gmail.com>
Date: Tue, 27 May 2014 18:57:33 -0600
Subject: [PATCH] add sum

---
 Makefile   |   1 +
 README.md  |   1 -
 sum/sum.rs | 129 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 130 insertions(+), 1 deletion(-)
 create mode 100644 sum/sum.rs

diff --git a/Makefile b/Makefile
index 4b48a3e29..34733f74d 100644
--- a/Makefile
+++ b/Makefile
@@ -23,6 +23,7 @@ PROGS       := \
   rmdir \
   sleep \
   seq \
+  sum \
   tac \
   tee \
   touch \
diff --git a/README.md b/README.md
index 46b23b1d6..67424489e 100644
--- a/README.md
+++ b/README.md
@@ -133,7 +133,6 @@ To do
 - stat
 - stdbuf
 - stty (in progress)
-- sum
 - sync
 - tac-pipe
 - tail
diff --git a/sum/sum.rs b/sum/sum.rs
new file mode 100644
index 000000000..830dec78e
--- /dev/null
+++ b/sum/sum.rs
@@ -0,0 +1,129 @@
+#![crate_id(name="sum", vers="1.0.0", author="T. Jameson Little")]
+#![feature(macro_rules)]
+
+/*
+* This file is part of the uutils coreutils package.
+*
+* (c) T. Jameson Little <t.jameson.little@gmail.com>
+*
+* For the full copyright and license information, please view the LICENSE file
+* that was distributed with this source code.
+*/
+
+extern crate getopts;
+extern crate libc;
+
+use std::os;
+use std::io::{File, IoResult, print};
+use std::io::stdio::{stdin_raw};
+
+#[path="../common/util.rs"]
+mod util;
+
+static VERSION: &'static str = "1.0.0";
+static NAME: &'static str = "sum";
+
+fn bsd_sum(mut reader: Box<Reader>) -> (uint, u16) {
+    let mut buf = ~[0, .. 1024];
+    let mut blocks_read = 0;
+    let mut checksum: u16 = 0;
+    loop {
+        match reader.read(buf) {
+            Ok(n) if n != 0 => {
+                blocks_read += 1;
+                for &byte in buf.slice_to(n).iter() {
+                    checksum = (checksum >> 1) + ((checksum & 1) << 15);
+                    checksum += byte as u16;
+                }
+            },
+            _ => break,
+        }
+    }
+
+    (blocks_read, checksum)
+}
+
+fn sysv_sum(mut reader: Box<Reader>) -> (uint, u16) {
+    let mut buf = ~[0, .. 512];
+    let mut blocks_read = 0;
+    let mut ret = 0;
+
+    loop {
+        match reader.read(buf) {
+            Ok(n) if n != 0 => {
+                blocks_read += 1;
+                for &byte in buf.slice_to(n).iter() {
+                    ret += byte as u32;
+                }
+            },
+            _ => break,
+        }
+    }
+
+    ret = (ret & 0xffff) + (ret >> 16);
+    ret = (ret & 0xffff) + (ret >> 16);
+
+    (blocks_read, ret as u16)
+}
+
+fn open(name: &str) -> IoResult<Box<Reader>> {
+	match name {
+		"-" => Ok(box stdin_raw() as Box<Reader>),
+		_ => {
+			let f = try!(File::open(&Path::new(name)));
+			Ok(box f as Box<Reader>)
+		}
+	}
+}
+
+fn main() {
+    let args = os::args();
+    let program = args.get(0).as_slice();
+    let opts = [
+        getopts::optflag("r", "", "use the BSD compatible algorithm (default)"),
+        getopts::optflag("s", "sysv", "use System V compatible algorithm"),
+        getopts::optflag("h", "help", "show this help message"),
+        getopts::optflag("v", "version", "print the version and exit"),
+    ];
+
+    let matches = match getopts::getopts(args.tail(), opts) {
+        Ok(m) => m,
+        Err(f) => crash!(1, "Invalid options\n{}", f.to_err_msg())
+    };
+
+    if matches.opt_present("help") {
+        println!("{} {}", program, VERSION);
+        println!("");
+        println!("Usage:");
+        println!("  {0:s} [OPTION]... [FILE]...", program);
+        println!("");
+        print(getopts::usage("checksum and count the blocks in a file", opts).as_slice());
+        println!("");
+        println!("With no FILE, or when  FILE is -, read standard input.");
+        return;
+    }
+    if matches.opt_present("version") {
+        println!("{} {}", program, VERSION);
+        return;
+    }
+
+    let sysv = matches.opt_present("sysv");
+
+    let file = if matches.free.is_empty() {
+        "-"
+    } else {
+        matches.free.get(0).as_slice()
+    };
+
+    let reader = match open(file) {
+        Ok(f) => f,
+        _ => crash!(1, "unable to open file")
+    };
+    let (blocks, sum) = if sysv {
+        sysv_sum(reader)
+    } else {
+        bsd_sum(reader)
+    };
+
+    println!("{} {}", sum, blocks);
+}