ls --dired -R: fix the positions (#5341)

* move get_offset_from_previous_line into a specific function

* dired: improve the -R support

* dired: fix the display with subdir

* ls --dired -R: fix the positions

* ls --dired -R: verify also the SUBDIRED coordinate

* ls --dired -R: add a long file name and fix a windows test

* dired: always put dired first in the args + minor fixes

Co-authored-by: Daniel Hofstetter <daniel.hofstetter@42dh.com>

* ls: add cognitive_complexity to silent a warning

---------

Co-authored-by: Daniel Hofstetter <daniel.hofstetter@42dh.com>

tests/by-util/test_ls.rs

@@ -3580,6 +3580,57 @@ fn test_ls_dired_recursive() {
         .stdout_contains("//DIRED-OPTIONS// --quoting-style");
 }
 
+#[test]
+fn test_ls_dired_recursive_multiple() {
+    let scene = TestScenario::new(util_name!());
+    let at = &scene.fixtures;
+
+    at.mkdir("d");
+    at.mkdir("d/d1");
+    at.mkdir("d/d2");
+    at.touch("d/d2/a");
+    at.touch("d/d2/c2");
+    at.touch("d/d1/f1");
+    at.touch("d/d1/file-long");
+
+    let mut cmd = scene.ucmd();
+    cmd.arg("--dired").arg("-l").arg("-R").arg("d");
+
+    let result = cmd.succeeds();
+
+    let output = result.stdout_str().to_string();
+    println!("Output:\n{}", output);
+
+    let dired_line = output
+        .lines()
+        .find(|&line| line.starts_with("//DIRED//"))
+        .unwrap();
+    let positions: Vec<usize> = dired_line
+        .split_whitespace()
+        .skip(1)
+        .map(|s| s.parse().unwrap())
+        .collect();
+    println!("Parsed byte positions: {:?}", positions);
+    assert_eq!(positions.len() % 2, 0); // Ensure there's an even number of positions
+
+    let filenames: Vec<String> = positions
+        .chunks(2)
+        .map(|chunk| {
+            let start_pos = chunk[0];
+            let end_pos = chunk[1];
+            let filename = String::from_utf8(output.as_bytes()[start_pos..=end_pos].to_vec())
+                .unwrap()
+                .trim()
+                .to_string();
+            println!("Extracted filename: {}", filename);
+            filename
+        })
+        .collect();
+
+    println!("Extracted filenames: {:?}", filenames);
+    assert_eq!(filenames, vec!["d1", "d2", "f1", "file-long", "a", "c2"]);
+}
+
 #[test]
 fn test_ls_dired_simple() {
     let scene = TestScenario::new(util_name!());
@@ -3679,6 +3730,57 @@ fn test_ls_dired_complex() {
     assert_eq!(filenames, vec!["a1", "a22", "a333", "a4444", "d"]);
 }
 
+#[test]
+fn test_ls_subdired_complex() {
+    let scene = TestScenario::new(util_name!());
+    let at = &scene.fixtures;
+
+    at.mkdir("dir1");
+    at.mkdir("dir1/d");
+    at.mkdir("dir1/c2");
+    at.touch("dir1/a1");
+    at.touch("dir1/a22");
+    at.touch("dir1/a333");
+    at.touch("dir1/c2/a4444");
+
+    let mut cmd = scene.ucmd();
+    cmd.arg("--dired").arg("-l").arg("-R").arg("dir1");
+    let result = cmd.succeeds();
+
+    let output = result.stdout_str().to_string();
+    println!("Output:\n{}", output);
+
+    let dired_line = output
+        .lines()
+        .find(|&line| line.starts_with("//SUBDIRED//"))
+        .unwrap();
+    let positions: Vec<usize> = dired_line
+        .split_whitespace()
+        .skip(1)
+        .map(|s| s.parse().unwrap())
+        .collect();
+    println!("Parsed byte positions: {:?}", positions);
+    assert_eq!(positions.len() % 2, 0); // Ensure there's an even number of positions
+
+    let dirnames: Vec<String> = positions
+        .chunks(2)
+        .map(|chunk| {
+            let start_pos = chunk[0];
+            let end_pos = chunk[1];
+            let dirname =
+                String::from_utf8(output.as_bytes()[start_pos..end_pos].to_vec()).unwrap();
+            println!("Extracted dirname: {}", dirname);
+            dirname
+        })
+        .collect();
+
+    println!("Extracted dirnames: {:?}", dirnames);
+    #[cfg(unix)]
+    assert_eq!(dirnames, vec!["dir1", "dir1/c2", "dir1/d"]);
+    #[cfg(windows)]
+    assert_eq!(dirnames, vec!["dir1", "dir1\\c2", "dir1\\d"]);
+}
+
 #[ignore = "issue #5396"]
 #[test]
 fn test_ls_cf_output_should_be_delimited_by_tab() {