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#![forbid(unsafe_code)]
use std::path::PathBuf;
use std::{env, ffi, fs, io, process};
extern crate weezl;
use weezl::{decode as delzw, encode as enlzw, BitOrder};
fn main() {
let args = env::args_os().skip(1);
let flags = Flags::from_args(args).unwrap_or_else(|ParamError| explain());
let out = io::stdout();
let out = out.lock();
let mut files = flags.files;
let input = files.pop().unwrap_or_else(explain);
if !files.is_empty() {
return explain();
}
let operation = flags.operation.unwrap_or_else(explain);
let min_code = if flags.min_code < 2 || flags.min_code > 12 {
return explain();
} else {
flags.min_code
};
let bit_order = flags.bit_order;
let result = match (input, operation) {
(Input::File(file), Operation::Encode) => (|| {
let data = fs::File::open(file)?;
let file = io::BufReader::with_capacity(1 << 26, data);
let mut encoder = enlzw::Encoder::new(bit_order, min_code);
encoder.into_stream(out).encode_all(file).status
})(),
(Input::Stdin, Operation::Encode) => {
let input = io::BufReader::with_capacity(1 << 26, io::stdin());
let mut encoder = enlzw::Encoder::new(bit_order, min_code);
encoder.into_stream(out).encode_all(input).status
}
(Input::File(file), Operation::Decode) => (|| {
let data = fs::File::open(file)?;
let file = io::BufReader::with_capacity(1 << 26, data);
let mut decoder = delzw::Decoder::new(bit_order, min_code);
decoder.into_stream(out).decode_all(file).status
})(),
(Input::Stdin, Operation::Decode) => {
let input = io::BufReader::with_capacity(1 << 26, io::stdin());
let mut decoder = delzw::Decoder::new(bit_order, min_code);
decoder.into_stream(out).decode_all(input).status
}
};
result.expect("Operation Failed: ");
}
struct Flags {
files: Vec<Input>,
operation: Option<Operation>,
min_code: u8,
bit_order: BitOrder,
}
struct ParamError;
enum Input {
File(PathBuf),
Stdin,
}
enum Operation {
Encode,
Decode,
}
fn explain<T>() -> T {
println!(
"Usage: lzw [-e|-d] <file>\n\
Arguments:\n\
-e\t operation encode (default)\n\
-d\t operation decode\n\
<file>\tfilepath or '-' for stdin"
);
process::exit(1);
}
impl Default for Flags {
fn default() -> Flags {
Flags {
files: vec![],
operation: None,
min_code: 8,
bit_order: BitOrder::Msb,
}
}
}
impl Flags {
fn from_args(mut args: impl Iterator<Item = ffi::OsString>) -> Result<Self, ParamError> {
let mut flags = Flags::default();
let mut operation = None;
loop {
match args.next().as_ref().and_then(|s| s.to_str()) {
Some("-d") | Some("--decode") => {
if operation.is_some() {
return Err(ParamError);
}
operation = Some(Operation::Decode);
}
Some("-e") | Some("--encode") => {
if operation.is_some() {
return Err(ParamError);
}
operation = Some(Operation::Encode);
}
Some("-w") | Some("--word-bits") => match args.next() {
None => return Err(ParamError),
Some(bits) => {
let st = bits.to_str().ok_or(ParamError)?;
flags.min_code = st.parse().ok().ok_or(ParamError)?;
}
},
Some("-le") | Some("--little-endian") => {
flags.bit_order = BitOrder::Lsb;
}
Some("-be") | Some("--big-endian") | Some("-ne") | Some("--network-endian") => {
flags.bit_order = BitOrder::Msb;
}
Some("-") => {
flags.files.push(Input::Stdin);
}
Some(other) if other.starts_with('-') => {
// Reserved for future use.
// -a: self-describing archive format, similar to actual compress
// -b: maximum bits
// -v: verbosity
// some compress compatibility mode? Probably through arg(0) though.
return Err(ParamError);
}
Some(file) => {
flags.files.push(Input::File(file.into()));
}
None => break,
};
}
flags.files.extend(args.map(|file| {
if let Some("-") = file.to_str() {
Input::Stdin
} else {
Input::File(file.into())
}
}));
flags.operation = operation;
Ok(flags)
}
}
|
