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cat utility refactoring:

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- Less if branches
 - Unnecessary range variable deleted
 - Optional fail-assertion commented
This commit is contained in:
evgeniy 2016-10-16 12:43:23 +02:00
parent 7bb5891810
commit dd16c58ab4
1 changed files with 110 additions and 86 deletions
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196
src/cat/cat.rs
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@ -1,17 +1,14 @@
#![crate_name = "uu_cat"]
/*
* This file is part of the uutils coreutils package.
*
* (c) Jordi Boggiano <j.boggiano@seld.be>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
// This file is part of the uutils coreutils package.
//
// (c) Jordi Boggiano <j.boggiano@seld.be>
//
// For the full copyright and license information, please view the LICENSE
// file that was distributed with this source code.
//
/* last synced with: cat (GNU coreutils) 8.13 */
extern crate libc;
// last synced with: cat (GNU coreutils) 8.13
#[macro_use]
extern crate uucore;
@ -21,15 +18,16 @@ use std::intrinsics::{copy_nonoverlapping};
use std::io::{stdout, stdin, stderr, Write, Read, Result};
use uucore::fs::is_stdin_interactive;
static SYNTAX: &'static str = "[OPTION]... [FILE]...";
static SYNTAX: &'static str = "[OPTION]... [FILE]...";
static SUMMARY: &'static str = "Concatenate FILE(s), or standard input, to standard output
With no FILE, or when FILE is -, read standard input.";
static LONG_HELP: &'static str = "";
With no FILE, or when FILE is -, read standard input.";
static LONG_HELP: &'static str = "";
pub fn uumain(args: Vec<String>) -> i32 {
let matches = new_coreopts!(SYNTAX, SUMMARY, LONG_HELP)
.optflag("A", "show-all", "equivalent to -vET")
.optflag("b", "number-nonblank",
.optflag("b",
"number-nonblank",
"number nonempty output lines, overrides -n")
.optflag("e", "", "equivalent to -vE")
.optflag("E", "show-ends", "display $ at end of each line")
@ -37,7 +35,8 @@ pub fn uumain(args: Vec<String>) -> i32 {
.optflag("s", "squeeze-blank", "suppress repeated empty output lines")
.optflag("t", "", "equivalent to -vT")
.optflag("T", "show-tabs", "display TAB characters as ^I")
.optflag("v", "show-nonprinting",
.optflag("v",
"show-nonprinting",
"use ^ and M- notation, except for LF (\\n) and TAB (\\t)")
.parse(args);
@ -48,19 +47,22 @@ pub fn uumain(args: Vec<String>) -> i32 {
} else {
NumberingMode::NumberNone
};
let show_nonprint = matches.opts_present(&["A".to_owned(), "e".to_owned(),
"t".to_owned(), "v".to_owned()]);
let show_ends = matches.opts_present(&["E".to_owned(), "A".to_owned(),
"e".to_owned()]);
let show_tabs = matches.opts_present(&["A".to_owned(), "T".to_owned(),
"t".to_owned()]);
let show_nonprint =
matches.opts_present(&["A".to_owned(), "e".to_owned(), "t".to_owned(), "v".to_owned()]);
let show_ends = matches.opts_present(&["E".to_owned(), "A".to_owned(), "e".to_owned()]);
let show_tabs = matches.opts_present(&["A".to_owned(), "T".to_owned(), "t".to_owned()]);
let squeeze_blank = matches.opt_present("s");
let mut files = matches.free;
if files.is_empty() {
files.push("-".to_owned());
}
exec(files, number_mode, show_nonprint, show_ends, show_tabs, squeeze_blank);
exec(files,
number_mode,
show_nonprint,
show_ends,
show_tabs,
squeeze_blank);
0
}
@ -72,29 +74,32 @@ enum NumberingMode {
NumberAll,
}
fn write_lines(files: Vec<String>, number: NumberingMode, squeeze_blank: bool,
show_ends: bool) {
fn write_lines(files: Vec<String>, number: NumberingMode, squeeze_blank: bool, show_ends: bool) {
// initialize end of line
let end_of_line = if show_ends {
"$\n".as_bytes()
} else {
"\n".as_bytes()
};
let mut line_counter: usize = 1;
for (mut reader, interactive) in files.iter().filter_map(|p| open(&p[..])) {
let mut in_buf = [0; 1024 * 31];
let mut in_buf = [0; 1024 * 31];
let mut out_buf = [0; 1024 * 64];
let mut writer = UnsafeWriter::new(&mut out_buf[..], stdout());
let mut at_line_start = true;
let mut one_blank_kept = false;
while let Ok(n) = reader.read(&mut in_buf) {
if n == 0 { break }
if n == 0 {
break;
}
let in_buf = &in_buf[..n];
let mut buf_pos = 0..n;
loop {
let mut pos = 0;
while pos < n {
writer.possibly_flush();
let pos = match buf_pos.next() {
Some(p) => p,
None => break,
};
if in_buf[pos] == '\n' as u8 {
if !at_line_start || !squeeze_blank || !one_blank_kept {
one_blank_kept = true;
@ -102,15 +107,13 @@ fn write_lines(files: Vec<String>, number: NumberingMode, squeeze_blank: bool,
(write!(&mut writer, "{0:6}\t", line_counter)).unwrap();
line_counter += 1;
}
if show_ends {
writer.write_all(&['$' as u8]).unwrap();
}
writer.write_all(&['\n' as u8]).unwrap();
writer.write_all(end_of_line).unwrap();
if interactive {
writer.flush().unwrap();
}
}
at_line_start = true;
pos += 1;
continue;
} else if one_blank_kept {
one_blank_kept = false;
@ -122,16 +125,13 @@ fn write_lines(files: Vec<String>, number: NumberingMode, squeeze_blank: bool,
match in_buf[pos..].iter().position(|c| *c == '\n' as u8) {
Some(p) => {
writer.write_all(&in_buf[pos..pos + p]).unwrap();
if show_ends {
writer.write_all(&['$' as u8]).unwrap();
}
writer.write_all(&['\n' as u8]).unwrap();
writer.write_all(end_of_line).unwrap();
if interactive {
writer.flush().unwrap();
}
buf_pos = pos + p + 1..n;
pos += p + 1;
at_line_start = true;
},
}
None => {
writer.write_all(&in_buf[pos..]).unwrap();
at_line_start = false;
@ -143,8 +143,24 @@ fn write_lines(files: Vec<String>, number: NumberingMode, squeeze_blank: bool,
}
}
fn write_bytes(files: Vec<String>, number: NumberingMode, squeeze_blank: bool,
show_ends: bool, show_nonprint: bool, show_tabs: bool) {
fn write_bytes(files: Vec<String>,
number: NumberingMode,
squeeze_blank: bool,
show_ends: bool,
show_tabs: bool,
show_nonprint: bool) {
// initialize end of line
let end_of_line = if show_ends {
"$\n".as_bytes()
} else {
"\n".as_bytes()
};
// initialize tab simbol
let tab = if show_tabs {
"^I".as_bytes()
} else {
"\t".as_bytes()
};
let mut line_counter: usize = 1;
@ -153,12 +169,14 @@ fn write_bytes(files: Vec<String>, number: NumberingMode, squeeze_blank: bool,
// Flush all 1024 iterations.
let mut flush_counter = 0usize..1024;
let mut in_buf = [0; 1024 * 32];
let mut in_buf = [0; 1024 * 32];
let mut out_buf = [0; 1024 * 64];
let mut writer = UnsafeWriter::new(&mut out_buf[..], stdout());
let mut at_line_start = true;
while let Ok(n) = reader.read(&mut in_buf) {
if n == 0 { break }
if n == 0 {
break;
}
for &byte in in_buf[..n].iter() {
if flush_counter.next().is_none() {
@ -171,10 +189,7 @@ fn write_bytes(files: Vec<String>, number: NumberingMode, squeeze_blank: bool,
(write!(&mut writer, "{0:6}\t", line_counter)).unwrap();
line_counter += 1;
}
if show_ends {
writer.write_all(&['$' as u8]).unwrap();
}
writer.write_all(&['\n' as u8]).unwrap();
writer.write_all(end_of_line).unwrap();
if interactive {
writer.flush().unwrap();
}
@ -187,30 +202,28 @@ fn write_bytes(files: Vec<String>, number: NumberingMode, squeeze_blank: bool,
line_counter += 1;
at_line_start = false;
}
// This code is slow because of the many branches. cat in glibc avoids
// this by having the whole loop inside show_nonprint.
if byte == '\t' as u8 {
if show_tabs {
writer.write_all("^I".as_bytes())
writer.write_all(tab)
} else if show_nonprint {
let byte = match byte {
128...255 => {
writer.write_all("M-".as_bytes()).unwrap();
byte - 128
}
_ => byte,
};
match byte {
0...31 => writer.write_all(&['^' as u8, byte + 64]),
127 => writer.write_all(&['^' as u8, byte - 64]),
_ => writer.write_all(&[byte]),
}
} else {
writer.write_all(&[byte])
}
} else if show_nonprint {
let byte = match byte {
128 ... 255 => {
writer.write_all("M-".as_bytes()).unwrap();
byte - 128
},
_ => byte,
};
match byte {
0 ... 31 => writer.write_all(&['^' as u8, byte + 64]),
127 => writer.write_all(&['^' as u8, byte - 64]),
_ => writer.write_all(&[byte]),
}
} else {
writer.write_all(&[byte])
}.unwrap();
.unwrap();
}
}
}
@ -222,18 +235,29 @@ fn write_fast(files: Vec<String>) {
for (mut reader, _) in files.iter().filter_map(|p| open(&p[..])) {
while let Ok(n) = reader.read(&mut in_buf) {
if n == 0 { break }
if n == 0 {
break;
}
// This interface is completely broken.
writer.write_all(&in_buf[..n]).unwrap();
}
}
}
fn exec(files: Vec<String>, number: NumberingMode, show_nonprint: bool,
show_ends: bool, show_tabs: bool, squeeze_blank: bool) {
fn exec(files: Vec<String>,
number: NumberingMode,
show_nonprint: bool,
show_ends: bool,
show_tabs: bool,
squeeze_blank: bool) {
if show_nonprint || show_tabs {
write_bytes(files, number, squeeze_blank, show_ends, show_nonprint, show_tabs);
write_bytes(files,
number,
squeeze_blank,
show_ends,
show_tabs,
show_nonprint);
} else if number != NumberingMode::NumberNone || squeeze_blank || show_ends {
write_lines(files, number, squeeze_blank, show_ends);
} else {
@ -253,7 +277,7 @@ fn open(path: &str) -> Option<(Box<Read>, bool)> {
Err(e) => {
(writeln!(&mut stderr(), "cat: {0}: {1}", path, e.to_string())).unwrap();
None
},
}
}
}
@ -266,7 +290,7 @@ struct UnsafeWriter<'a, W: Write> {
impl<'a, W: Write> UnsafeWriter<'a, W> {
fn new(buf: &'a mut [u8], inner: W) -> UnsafeWriter<'a, W> {
let threshold = buf.len()/2;
let threshold = buf.len() / 2;
UnsafeWriter {
inner: inner,
buf: buf,
@ -296,21 +320,21 @@ impl<'a, W: Write> UnsafeWriter<'a, W> {
}
}
#[inline(never)]
fn fail() -> ! {
panic!("assertion failed");
}
//#[inline(never)]
//fn fail() -> ! {
// panic!("assertion failed");
//}
impl<'a, W: Write> Write for UnsafeWriter<'a, W> {
fn write(&mut self, buf: &[u8]) -> Result<usize> {
let dst = &mut self.buf[self.pos..];
//let dst = &mut self.buf[self.pos..];
let len = buf.len();
if len > dst.len() {
fail();
}
unsafe {
copy_nonoverlapping(buf.as_ptr(), dst.as_mut_ptr(), len)
}
// assertion is true for current code
// and it is a bottlneck place
// if len > dst.len() {
// fail();
// }
unsafe { copy_nonoverlapping(buf.as_ptr(), self.buf[self.pos..].as_mut_ptr(), len) }
self.pos += len;
Ok(len)
}