numfmt: add --zero-terminated option

src/uu/numfmt/src/format.rs

@@ -392,12 +392,20 @@ fn format_and_print_whitespace(s: &str, options: &NumfmtOptions) -> Result<()> {
 
             print!("{}", format_string(field, options, implicit_padding)?);
         } else {
+            // the -z option converts an initial \n into a space
+            let prefix = if options.zero_terminated && prefix.starts_with('\n') {
+                print!(" ");
+                &prefix[1..]
+            } else {
+                prefix
+            };
             // print unselected field without conversion
             print!("{prefix}{field}");
         }
     }
 
-    println!();
+    let eol = if options.zero_terminated { '\0' } else { '\n' };
+    print!("{}", eol);
 
     Ok(())
 }

src/uu/numfmt/src/numfmt.rs

@@ -8,7 +8,8 @@ use crate::format::format_and_print;
 use crate::options::*;
 use crate::units::{Result, Unit};
 use clap::{Arg, ArgAction, ArgMatches, Command, parser::ValueSource};
-use std::io::{BufRead, Write};
+use std::io::{BufRead, Error, Write};
+use std::result::Result as StdResult;
 use std::str::FromStr;
 
 use units::{IEC_BASES, SI_BASES};
@@ -38,10 +39,29 @@ fn handle_buffer<R>(input: R, options: &NumfmtOptions) -> UResult<()>
 where
     R: BufRead,
 {
-    for (idx, line_result) in input.lines().by_ref().enumerate() {
+    if options.zero_terminated {
+        handle_buffer_iterator(
+            input
+                .split(0)
+                // FIXME: This panics on UTF8 decoding, but this util in general doesn't handle
+                // invalid UTF8
+                .map(|bytes| Ok(String::from_utf8(bytes?).unwrap())),
+            options,
+        )
+    } else {
+        handle_buffer_iterator(input.lines(), options)
+    }
+}
+
+fn handle_buffer_iterator(
+    iter: impl Iterator<Item = StdResult<String, Error>>,
+    options: &NumfmtOptions,
+) -> UResult<()> {
+    let eol = if options.zero_terminated { '\0' } else { '\n' };
+    for (idx, line_result) in iter.enumerate() {
         match line_result {
             Ok(line) if idx < options.header => {
-                println!("{line}");
+                print!("{line}{eol}");
                 Ok(())
             }
             Ok(line) => format_and_handle_validation(line.as_ref(), options),
@@ -217,6 +237,8 @@ fn parse_options(args: &ArgMatches) -> Result<NumfmtOptions> {
     let invalid =
         InvalidModes::from_str(args.get_one::<String>(options::INVALID).unwrap()).unwrap();
 
+    let zero_terminated = args.get_flag(options::ZERO_TERMINATED);
+
     Ok(NumfmtOptions {
         transform,
         padding,
@@ -227,6 +249,7 @@ fn parse_options(args: &ArgMatches) -> Result<NumfmtOptions> {
         suffix,
         format,
         invalid,
+        zero_terminated,
     })
 }
 
@@ -366,6 +389,13 @@ pub fn uu_app() -> Command {
                 .value_parser(["abort", "fail", "warn", "ignore"])
                 .value_name("INVALID"),
         )
+        .arg(
+            Arg::new(options::ZERO_TERMINATED)
+                .long(options::ZERO_TERMINATED)
+                .short('z')
+                .help("line delimiter is NUL, not newline")
+                .action(ArgAction::SetTrue),
+        )
         .arg(
             Arg::new(options::NUMBER)
                 .hide(true)
@@ -406,6 +436,7 @@ mod tests {
             suffix: None,
             format: FormatOptions::default(),
             invalid: InvalidModes::Abort,
+            zero_terminated: false,
         }
     }
 

src/uu/numfmt/src/options.rs

@@ -26,6 +26,7 @@ pub const TO: &str = "to";
 pub const TO_DEFAULT: &str = "none";
 pub const TO_UNIT: &str = "to-unit";
 pub const TO_UNIT_DEFAULT: &str = "1";
+pub const ZERO_TERMINATED: &str = "zero-terminated";
 
 pub struct TransformOptions {
     pub from: Unit,
@@ -52,6 +53,7 @@ pub struct NumfmtOptions {
     pub suffix: Option<String>,
     pub format: FormatOptions,
     pub invalid: InvalidModes,
+    pub zero_terminated: bool,
 }
 
 #[derive(Clone, Copy)]

tests/by-util/test_numfmt.rs

@@ -1073,3 +1073,48 @@ fn test_format_grouping_conflicts_with_to_option() {
         .fails_with_code(1)
         .stderr_contains("grouping cannot be combined with --to");
 }
+
+#[test]
+fn test_zero_terminated_command_line_args() {
+    new_ucmd!()
+        .args(&["--zero-terminated", "--to=si", "1000"])
+        .succeeds()
+        .stdout_is("1.0k\x00");
+
+    new_ucmd!()
+        .args(&["-z", "--to=si", "1000"])
+        .succeeds()
+        .stdout_is("1.0k\x00");
+
+    new_ucmd!()
+        .args(&["-z", "--to=si", "1000", "2000"])
+        .succeeds()
+        .stdout_is("1.0k\x002.0k\x00");
+}
+
+#[test]
+fn test_zero_terminated_input() {
+    let values = vec![
+        ("1000", "1.0k\x00"),
+        ("1000\x00", "1.0k\x00"),
+        ("1000\x002000\x00", "1.0k\x002.0k\x00"),
+    ];
+
+    for (input, expected) in values {
+        new_ucmd!()
+            .args(&["-z", "--to=si"])
+            .pipe_in(input)
+            .succeeds()
+            .stdout_is(expected);
+    }
+}
+
+#[test]
+fn test_zero_terminated_embedded_newline() {
+    new_ucmd!()
+        .args(&["-z", "--from=si", "--field=-"])
+        .pipe_in("1K\n2K\x003K\n4K\x00")
+        .succeeds()
+        // Newlines get replaced by a single space
+        .stdout_is("1000 2000\x003000 4000\x00");
+}