Merge pull request uutils#8804 from sylvestre/fold-perf

fold: improve the performances - now same as GNU

Author: cakebaker

src/uu/fold/src/fold.rs

@@ -7,7 +7,7 @@
 
 use clap::{Arg, ArgAction, Command};
 use std::fs::File;
-use std::io::{BufRead, BufReader, Read, Write, stdin, stdout};
+use std::io::{BufRead, BufReader, BufWriter, Read, Write, stdin, stdout};
 use std::path::Path;
 use uucore::display::Quotable;
 use uucore::error::{FromIo, UResult, USimpleError};
@@ -108,6 +108,8 @@ fn handle_obsolete(args: &[String]) -> (Vec<String>, Option<String>) {
 }
 
 fn fold(filenames: &[String], bytes: bool, spaces: bool, width: usize) -> UResult<()> {
+ let mut output = BufWriter::new(stdout());
+
  for filename in filenames {
  let filename: &str = filename;
  let mut stdin_buf;
@@ -121,11 +123,15 @@ fn fold(filenames: &[String], bytes: bool, spaces: bool, width: usize) -> UResul
  });
 
  if bytes {
- fold_file_bytewise(buffer, spaces, width)?;
+ fold_file_bytewise(buffer, spaces, width, &mut output)?;
  } else {
- fold_file(buffer, spaces, width)?;
+ fold_file(buffer, spaces, width, &mut output)?;
  }
  }
+
+ output
+ .flush()
+ .map_err_context(|| translate!("fold-error-failed-to-write"))?;
  Ok(())
 }
 
@@ -137,7 +143,12 @@ fn fold(filenames: &[String], bytes: bool, spaces: bool, width: usize) -> UResul
 /// to all other characters in the stream.
 ///
 /// If `spaces` is `true`, attempt to break lines at whitespace boundaries.
-fn fold_file_bytewise<T: Read>(mut file: BufReader<T>, spaces: bool, width: usize) -> UResult<()> {
+fn fold_file_bytewise<T: Read, W: Write>(
+ mut file: BufReader<T>,
+ spaces: bool,
+ width: usize,
+ output: &mut W,
+) -> UResult<()> {
  let mut line = Vec::new();
 
  loop {
@@ -150,7 +161,7 @@ fn fold_file_bytewise<T: Read>(mut file: BufReader<T>, spaces: bool, width: usiz
  }
 
  if line == [NL] {
- println!();
+ output.write_all(&[NL])?;
  line.truncate(0);
  continue;
  }
@@ -189,10 +200,10 @@ fn fold_file_bytewise<T: Read>(mut file: BufReader<T>, spaces: bool, width: usiz
  let at_eol = i >= len;
 
  if at_eol {
- stdout().write_all(slice)?;
+ output.write_all(slice)?;
  } else {
- stdout().write_all(slice)?;
- stdout().write_all(&[NL])?;
+ output.write_all(slice)?;
+ output.write_all(&[NL])?;
  }
  }
 
@@ -211,7 +222,12 @@ fn fold_file_bytewise<T: Read>(mut file: BufReader<T>, spaces: bool, width: usiz
 /// If `spaces` is `true`, attempt to break lines at whitespace boundaries.
 #[allow(unused_assignments)]
 #[allow(clippy::cognitive_complexity)]
-fn fold_file<T: Read>(mut file: BufReader<T>, spaces: bool, width: usize) -> UResult<()> {
+fn fold_file<T: Read, W: Write>(
+ mut file: BufReader<T>,
+ spaces: bool,
+ width: usize,
+ writer: &mut W,
+) -> UResult<()> {
  let mut line = Vec::new();
  let mut output = Vec::new();
  let mut col_count = 0;
@@ -229,8 +245,8 @@ fn fold_file<T: Read>(mut file: BufReader<T>, spaces: bool, width: usize) -> URe
  None => output.len(),
  };
 
- stdout().write_all(&output[..consume])?;
- stdout().write_all(&[NL])?;
+ writer.write_all(&output[..consume])?;
+ writer.write_all(&[NL])?;
  output.drain(..consume);
 
  // we know there are no tabs left in output, so each char counts
@@ -289,7 +305,7 @@ fn fold_file<T: Read>(mut file: BufReader<T>, spaces: bool, width: usize) -> URe
  }
 
  if !output.is_empty() {
- stdout().write_all(&output)?;
+ writer.write_all(&output)?;
  output.truncate(0);
  }