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#[macro_use]
extern crate uucore;
use clap::{App, Arg};
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");
static USAGE: &str =
"[OPTION]... [FILE]...\nWith no FILE, or when FILE is -, read standard input.";
static SUMMARY: &str = "Checksum and count the blocks in a file.";
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 path = &Path::new(name);
if path.is_dir() {
return Err(std::io::Error::new(
std::io::ErrorKind::InvalidInput,
"Is a directory",
));
};
if !path.metadata().is_ok() {
return Err(std::io::Error::new(
std::io::ErrorKind::NotFound,
"No such file or directory",
));
};
let f = File::open(path)?;
Ok(Box::new(f) as Box<dyn Read>)
}
}
}
mod options {
pub static FILE: &str = "file";
pub static BSD_COMPATIBLE: &str = "r";
pub static SYSTEM_V_COMPATIBLE: &str = "sysv";
}
pub fn uumain(args: impl uucore::Args) -> i32 {
let args = args.collect_str();
let matches = App::new(executable!())
.name(NAME)
.version(VERSION)
.usage(USAGE)
.about(SUMMARY)
.arg(Arg::with_name(options::FILE).multiple(true).hidden(true))
.arg(
Arg::with_name(options::BSD_COMPATIBLE)
.short(options::BSD_COMPATIBLE)
.help("use the BSD compatible algorithm (default)"),
)
.arg(
Arg::with_name(options::SYSTEM_V_COMPATIBLE)
.short("s")
.long(options::SYSTEM_V_COMPATIBLE)
.help("use the BSD compatible algorithm (default)"),
)
.get_matches_from(args);
let files: Vec<String> = match matches.values_of(options::FILE) {
Some(v) => v.clone().map(|v| v.to_owned()).collect(),
None => vec!["-".to_owned()],
};
let sysv = matches.is_present(options::SYSTEM_V_COMPATIBLE);
let print_names = if sysv {
files.len() > 1 || files[0] != "-"
} else {
files.len() > 1
};
let mut exit_code = 0;
for file in &files {
let reader = match open(file) {
Ok(f) => f,
Err(error) => {
show_error!("'{}' {}", file, error);
exit_code = 2;
continue;
}
};
let (blocks, sum) = if sysv {
sysv_sum(reader)
} else {
bsd_sum(reader)
};
if print_names {
println!("{} {} {}", sum, blocks, file);
} else {
println!("{} {}", sum, blocks);
}
}
exit_code
}