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#[macro_use]
extern crate uucore;
use std::fs::File;
use std::io::{stdin, Read, Result};
use std::path::Path;
static NAME: &str = "sum";
static VERSION: &str = env!("CARGO_PKG_VERSION");
fn bsd_sum(mut reader: Box<dyn Read>) -> (usize, u16) {
let mut buf = [0; 1024];
let mut blocks_read = 0;
let mut checksum: u16 = 0;
loop {
match reader.read(&mut buf) {
Ok(n) if n != 0 => {
blocks_read += 1;
for &byte in buf[..n].iter() {
checksum = (checksum >> 1) + ((checksum & 1) << 15);
checksum = checksum.wrapping_add(u16::from(byte));
}
}
_ => break,
}
}
(blocks_read, checksum)
}
fn sysv_sum(mut reader: Box<dyn Read>) -> (usize, u16) {
let mut buf = [0; 512];
let mut blocks_read = 0;
let mut ret = 0u32;
loop {
match reader.read(&mut buf) {
Ok(n) if n != 0 => {
blocks_read += 1;
for &byte in buf[..n].iter() {
ret = ret.wrapping_add(u32::from(byte));
}
}
_ => break,
}
}
ret = (ret & 0xffff) + (ret >> 16);
ret = (ret & 0xffff) + (ret >> 16);
(blocks_read, ret as u16)
}
fn open(name: &str) -> Result<Box<dyn Read>> {
match name {
"-" => Ok(Box::new(stdin()) as Box<dyn Read>),
_ => {
let f = File::open(&Path::new(name))?;
Ok(Box::new(f) as Box<dyn Read>)
}
}
}
pub fn uumain(args: impl uucore::Args) -> i32 {
let args = args.collect_str();
let mut opts = getopts::Options::new();
opts.optflag("r", "", "use the BSD compatible algorithm (default)");
opts.optflag("s", "sysv", "use System V compatible algorithm");
opts.optflag("h", "help", "show this help message");
opts.optflag("v", "version", "print the version and exit");
let matches = match opts.parse(&args[1..]) {
Ok(m) => m,
Err(f) => crash!(1, "Invalid options\n{}", f),
};
if matches.opt_present("help") {
let msg = format!(
"{0} {1}
Usage:
{0} [OPTION]... [FILE]...
Checksum and count the blocks in a file.",
NAME, VERSION
);
println!(
"{}\nWith no FILE, or when FILE is -, read standard input.",
opts.usage(&msg)
);
return 0;
}
if matches.opt_present("version") {
println!("{} {}", NAME, VERSION);
return 0;
}
let sysv = matches.opt_present("sysv");
let files = if matches.free.is_empty() {
vec!["-".to_owned()]
} else {
matches.free
};
let print_names = if sysv {
files.len() > 1 || files[0] != "-"
} else {
files.len() > 1
};
for file in &files {
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)
};
if print_names {
println!("{} {} {}", sum, blocks, file);
} else {
println!("{} {}", sum, blocks);
}
}
0
}