ls: consolidate duplicate calculate_padding_collection functions

Removes 76 lines of duplicate code by merging Unix and non-Unix versions
of calculate_padding_collection into a single function using conditional
compilation. Also adds should_display_leading_info helper method to
eliminate repeated platform-specific logic patterns.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: sylvestre

src/uu/ls/src/ls.rs

@@ -1244,6 +1244,19 @@ impl Config {
             tab_size,
         })
     }
+
+    /// Check if leading info (inode and/or block size) should be displayed
+    #[inline]
+    fn should_display_leading_info(&self) -> bool {
+        #[cfg(unix)]
+        {
+            self.inode || self.alloc_size
+        }
+        #[cfg(not(unix))]
+        {
+            self.alloc_size
+        }
+    }
 }
 
 #[uucore::main]
@@ -2687,10 +2700,7 @@ fn display_items(
         let padding_collection = calculate_padding_collection(items, config, state);
 
         for item in items {
-            #[cfg(unix)]
-            let should_display_leading_info = config.inode || config.alloc_size;
-            #[cfg(not(unix))]
-            let should_display_leading_info = config.alloc_size;
+            let should_display_leading_info = config.should_display_leading_info();
 
             if should_display_leading_info {
                 let more_info = display_additional_leading_info(item, &padding_collection, config)?;
@@ -2721,10 +2731,7 @@ fn display_items(
 
         let mut names_vec = Vec::new();
 
-        #[cfg(unix)]
-        let should_display_leading_info = config.inode || config.alloc_size;
-        #[cfg(not(unix))]
-        let should_display_leading_info = config.alloc_size;
+        let should_display_leading_info = config.should_display_leading_info();
 
         for i in items {
             let more_info = if should_display_leading_info {
@@ -3587,20 +3594,22 @@ fn get_security_context<'a>(
     Cow::Borrowed(SUBSTITUTE_STRING)
 }
 
-#[cfg(unix)]
 fn calculate_padding_collection(
     items: &[PathData],
     config: &Config,
     state: &mut ListState,
 ) -> PaddingCollection {
     let mut padding_collections = PaddingCollection {
+        #[cfg(unix)]
         inode: 1,
         link_count: 1,
         uname: 1,
         group: 1,
         context: 1,
         size: 1,
+        #[cfg(unix)]
         major: 1,
+        #[cfg(unix)]
         minor: 1,
         block_size: 1,
     };
@@ -3646,56 +3655,25 @@ fn calculate_padding_collection(
                 }
             }
 
-            if items.len() == 1usize {
-                padding_collections.size = 0usize;
-                padding_collections.major = 0usize;
-                padding_collections.minor = 0usize;
-            } else {
-                padding_collections.major = major_len.max(padding_collections.major);
-                padding_collections.minor = minor_len.max(padding_collections.minor);
-                padding_collections.size = size_len
-                    .max(padding_collections.size)
-                    .max(padding_collections.major);
+            #[cfg(unix)]
+            {
+                if items.len() == 1usize {
+                    padding_collections.size = 0usize;
+                    padding_collections.major = 0usize;
+                    padding_collections.minor = 0usize;
+                } else {
+                    padding_collections.major = major_len.max(padding_collections.major);
+                    padding_collections.minor = minor_len.max(padding_collections.minor);
+                    padding_collections.size = size_len
+                        .max(padding_collections.size)
+                        .max(padding_collections.major);
+                }
             }
-        }
-    }
-
-    padding_collections
-}
-
-#[cfg(not(unix))]
-fn calculate_padding_collection(
-    items: &[PathData],
-    config: &Config,
-    state: &mut ListState,
-) -> PaddingCollection {
-    let mut padding_collections = PaddingCollection {
-        link_count: 1,
-        uname: 1,
-        group: 1,
-        context: 1,
-        size: 1,
-        block_size: 1,
-    };
-
-    for item in items {
-        if config.alloc_size {
-            if let Some(md) = item.metadata() {
-                let block_size_len = display_size(get_block_size(md, config), config).len();
-                padding_collections.block_size = block_size_len.max(padding_collections.block_size);
+            #[cfg(not(unix))]
+            {
+                padding_collections.size = size_len.max(padding_collections.size);
             }
         }
-
-        let context_len = item.security_context(config).len();
-        let (link_count_len, uname_len, group_len, size_len, _major_len, _minor_len) =
-            display_dir_entry_size(item, config, state);
-        padding_collections.link_count = link_count_len.max(padding_collections.link_count);
-        padding_collections.uname = uname_len.max(padding_collections.uname);
-        padding_collections.group = group_len.max(padding_collections.group);
-        if config.context {
-            padding_collections.context = context_len.max(padding_collections.context);
-        }
-        padding_collections.size = size_len.max(padding_collections.size);
     }
 
     padding_collections