sort: immediately compare whole lines if they parse as numbers

src/uu/sort/BENCHMARKING.md

@@ -24,8 +24,19 @@ Run `cargo build --release` before benchmarking after you make a change!
 
 ## Sorting numbers
 
-- Generate a list of numbers: `seq 0 100000 | sort -R > shuffled_numbers.txt`.
-- Benchmark numeric sorting with hyperfine: `hyperfine "target/release/coreutils sort shuffled_numbers.txt -n -o output.txt"`.
+- Generate a list of numbers:
+  ```
+  shuf -i 1-1000000 -n 1000000 > shuffled_numbers.txt
+  # or
+  seq 1 1000000 | sort -R > shuffled_numbers.txt
+  ```
+- Benchmark numeric sorting with hyperfine
+  ```
+  hyperfine --warmup 3 \
+    '/tmp/gnu-sort -n /tmp/shuffled_numbers.txt'
+    '/tmp/uu_before sort -n /tmp/shuffled_numbers.txt'
+    '/tmp/uu_after sort -n /tmp/shuffled_numbers.txt'
+  ```
 
 ## Sorting numbers with -g
 

src/uu/sort/src/chunks.rs

@@ -42,6 +42,7 @@ pub struct LineData<'a> {
     pub selections: Vec<&'a str>,
     pub num_infos: Vec<NumInfo>,
     pub parsed_floats: Vec<GeneralF64ParseResult>,
+    pub line_num_floats: Vec<Option<f64>>,
 }
 
 impl Chunk {
@@ -52,6 +53,7 @@ impl Chunk {
             contents.line_data.selections.clear();
             contents.line_data.num_infos.clear();
             contents.line_data.parsed_floats.clear();
+            contents.line_data.line_num_floats.clear();
             let lines = unsafe {
                 // SAFETY: It is safe to (temporarily) transmute to a vector of lines with a longer lifetime,
                 // because the vector is empty.
@@ -73,13 +75,15 @@ impl Chunk {
                 selections,
                 std::mem::take(&mut contents.line_data.num_infos),
                 std::mem::take(&mut contents.line_data.parsed_floats),
+                std::mem::take(&mut contents.line_data.line_num_floats),
             )
         });
         RecycledChunk {
             lines: recycled_contents.0,
             selections: recycled_contents.1,
             num_infos: recycled_contents.2,
             parsed_floats: recycled_contents.3,
+            line_num_floats: recycled_contents.4,
             buffer: self.into_owner(),
         }
     }
@@ -97,6 +101,7 @@ pub struct RecycledChunk {
     selections: Vec<&'static str>,
     num_infos: Vec<NumInfo>,
     parsed_floats: Vec<GeneralF64ParseResult>,
+    line_num_floats: Vec<Option<f64>>,
     buffer: Vec<u8>,
 }
 
@@ -107,6 +112,7 @@ impl RecycledChunk {
             selections: Vec::new(),
             num_infos: Vec::new(),
             parsed_floats: Vec::new(),
+            line_num_floats: Vec::new(),
             buffer: vec![0; capacity],
         }
     }
@@ -149,6 +155,7 @@ pub fn read<T: Read>(
         selections,
         num_infos,
         parsed_floats,
+        line_num_floats,
         mut buffer,
     } = recycled_chunk;
     if buffer.len() < carry_over.len() {
@@ -184,6 +191,7 @@ pub fn read<T: Read>(
                 selections,
                 num_infos,
                 parsed_floats,
+                line_num_floats,
             };
             parse_lines(read, &mut lines, &mut line_data, separator, settings);
             Ok(ChunkContents { lines, line_data })
@@ -207,6 +215,7 @@ fn parse_lines<'a>(
     assert!(line_data.selections.is_empty());
     assert!(line_data.num_infos.is_empty());
     assert!(line_data.parsed_floats.is_empty());
+    assert!(line_data.line_num_floats.is_empty());
     let mut token_buffer = vec![];
     lines.extend(
         read.split(separator as char)

src/uu/sort/src/sort.rs

@@ -460,6 +460,13 @@ impl<'a> Line<'a> {
         if settings.precomputed.needs_tokens {
             tokenize(line, settings.separator, token_buffer);
         }
+        if settings.mode == SortMode::Numeric {
+            // exclude inf, nan, scientific notation
+            let line_num_float = (!line.contains(char::is_alphabetic))
+                .then(|| line.parse::<f64>().ok())
+                .flatten();
+            line_data.line_num_floats.push(line_num_float);
+        }
         for (selector, selection) in settings
             .selectors
             .iter()
@@ -1563,6 +1570,24 @@ fn compare_by<'a>(
     let mut selection_index = 0;
     let mut num_info_index = 0;
     let mut parsed_float_index = 0;
+
+    if let (Some(Some(a_f64)), Some(Some(b_f64))) = (
+        a_line_data.line_num_floats.get(a.index),
+        b_line_data.line_num_floats.get(b.index),
+    ) {
+        // we don't use total_cmp() because it always sorts -0 before 0
+        if let Some(cmp) = a_f64.partial_cmp(b_f64) {
+            // don't trust `Ordering::Equal` if lines are not fully equal
+            if cmp != Ordering::Equal || a.line == b.line {
+                return if global_settings.reverse {
+                    cmp.reverse()
+                } else {
+                    cmp
+                };
+            }
+        }
+    }
+
     for selector in &global_settings.selectors {
         let (a_str, b_str) = if selector.needs_selection {
             let selections = (