coreutils/sum/sum.rs

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2014-05-28 00:57:33 +00:00
#![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>)
}
}
}
#[allow(dead_code)]
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fn main() { uumain(os::args()); }
pub fn uumain(args: Vec<String>) {
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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);
}