From d52fbe5e5001adf3cc38bccf3458f79307ae90d7 Mon Sep 17 00:00:00 2001
From: Yunus Ozen <94426948+ozenyunus35@users.noreply.github.com>
Date: Fri, 23 Oct 2026 01:10:46 +0300
Subject: [PATCH] od: print -S offsets through InputOffset

Follow-up to #15625: the strings mode had its own copy of the offset
formats. InputOffset now implements Display, format_byte_offset uses
it, and -S writes the offset through it without an extra allocation.
---
 src/uu/od/src/input_offset.rs | 28 ++++++++++++++++++----------
 src/uu/od/src/od.rs           | 11 ++++++-----
 2 files changed, 24 insertions(+), 15 deletions(-)

diff --git a/src/uu/od/src/input_offset.rs b/src/uu/od/src/input_offset.rs
index 6411b9d678b..6e5e36b5579 100644
--- a/src/uu/od/src/input_offset.rs
+++ b/src/uu/od/src/input_offset.rs
@@ -3,6 +3,7 @@
 // For the full copyright and license information, please view the LICENSE
 // file that was distributed with this source code.
 
+use std::fmt;
 use std::io::{self, Write};
 
 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
@@ -49,16 +50,7 @@ impl InputOffset {
 
     /// returns a string with the current byte offset
     pub fn format_byte_offset(&self) -> String {
-        match (self.radix, self.label) {
-            (Radix::Decimal, None) => format!("{:07}", self.byte_pos),
-            (Radix::Decimal, Some(l)) => format!("{:07} ({l:07})", self.byte_pos),
-            (Radix::Hexadecimal, None) => format!("{:06x}", self.byte_pos),
-            (Radix::Hexadecimal, Some(l)) => format!("{:06x} ({l:06x})", self.byte_pos),
-            (Radix::Octal, None) => format!("{:07o}", self.byte_pos),
-            (Radix::Octal, Some(l)) => format!("{:07o} ({l:07o})", self.byte_pos),
-            (Radix::NoPrefix, None) => String::new(),
-            (Radix::NoPrefix, Some(l)) => format!("({l:07o})"),
-        }
+        self.to_string()
     }
 
     /// Prints the byte offset followed by a newline, or nothing at all if
@@ -71,6 +63,22 @@ impl InputOffset {
     }
 }
 
+/// Writes the current byte offset, as [`InputOffset::format_byte_offset`] returns it.
+impl fmt::Display for InputOffset {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match (self.radix, self.label) {
+            (Radix::Decimal, None) => write!(f, "{:07}", self.byte_pos),
+            (Radix::Decimal, Some(l)) => write!(f, "{:07} ({l:07})", self.byte_pos),
+            (Radix::Hexadecimal, None) => write!(f, "{:06x}", self.byte_pos),
+            (Radix::Hexadecimal, Some(l)) => write!(f, "{:06x} ({l:06x})", self.byte_pos),
+            (Radix::Octal, None) => write!(f, "{:07o}", self.byte_pos),
+            (Radix::Octal, Some(l)) => write!(f, "{:07o} ({l:07o})", self.byte_pos),
+            (Radix::NoPrefix, None) => Ok(()),
+            (Radix::NoPrefix, Some(l)) => write!(f, "({l:07o})"),
+        }
+    }
+}
+
 #[test]
 fn test_input_offset() {
     let mut sut = InputOffset::new(Radix::Hexadecimal, 10, None);
diff --git a/src/uu/od/src/od.rs b/src/uu/od/src/od.rs
index 79e497b1d31..badc58b00ee 100644
--- a/src/uu/od/src/od.rs
+++ b/src/uu/od/src/od.rs
@@ -622,11 +622,12 @@ fn extract_strings_from_input(
     // Helper function to format and print a string
     let mut print_string = |offset: u64, string: &[u8]| -> std::io::Result<()> {
         let string_content = String::from_utf8_lossy(string);
-        match radix {
-            Radix::NoPrefix => writeln!(writer, "{string_content}"),
-            Radix::Decimal => writeln!(writer, "{offset:07} {string_content}"),
-            Radix::Hexadecimal => writeln!(writer, "{offset:06x} {string_content}"),
-            Radix::Octal => writeln!(writer, "{offset:07o} {string_content}"),
+        if radix == Radix::NoPrefix {
+            writeln!(writer, "{string_content}")
+        } else {
+            // Same offset format as the normal dump
+            let offset = InputOffset::new(radix, offset, None);
+            writeln!(writer, "{offset} {string_content}")
         }
     };