tr: refactor and introduce simd to get important perf win

src/uu/tr/Cargo.toml

@@ -22,6 +22,7 @@ nom = { workspace = true }
 clap = { workspace = true }
 uucore = { workspace = true, features = ["fs"] }
 fluent = { workspace = true }
+bytecount = { workspace = true, features = ["runtime-dispatch-simd"] }
 
 [[bin]]
 name = "tr"

src/uu/tr/src/operation.rs

@@ -26,6 +26,11 @@ use uucore::translate;
 
 use uucore::show_warning;
 
+/// Common trait for operations that can process chunks of data
+pub trait ChunkProcessor {
+    fn process_chunk(&self, input: &[u8], output: &mut Vec<u8>);
+}
+
 #[derive(Debug, Clone)]
 pub enum BadSequence {
     MissingCharClassName,
@@ -592,7 +597,7 @@ fn set_to_bitmap(set: &[u8]) -> [bool; 256] {
 
 #[derive(Debug)]
 pub struct DeleteOperation {
-    delete_table: [bool; 256],
+    pub(crate) delete_table: [bool; 256],
 }
 
 impl DeleteOperation {
@@ -610,9 +615,30 @@ impl SymbolTranslator for DeleteOperation {
     }
 }
 
+impl ChunkProcessor for DeleteOperation {
+    fn process_chunk(&self, input: &[u8], output: &mut Vec<u8>) {
+        use crate::simd::{find_single_change, process_single_delete};
+
+        // Check if this is single character deletion
+        if let Some((delete_char, _)) =
+            find_single_change(&self.delete_table, |_, &should_delete| should_delete)
+        {
+            process_single_delete(input, output, delete_char);
+        } else {
+            // Standard deletion
+            output.extend(
+                input
+                    .iter()
+                    .filter(|&&b| !self.delete_table[b as usize])
+                    .copied(),
+            );
+        }
+    }
+}
+
 #[derive(Debug)]
 pub struct TranslateOperation {
-    translation_table: [u8; 256],
+    pub(crate) translation_table: [u8; 256],
 }
 
 impl TranslateOperation {
@@ -645,6 +671,23 @@ impl SymbolTranslator for TranslateOperation {
     }
 }
 
+impl ChunkProcessor for TranslateOperation {
+    fn process_chunk(&self, input: &[u8], output: &mut Vec<u8>) {
+        use crate::simd::{find_single_change, process_single_char_replace};
+
+        // Check if this is a simple single-character translation
+        if let Some((source, target)) =
+            find_single_change(&self.translation_table, |i, &val| val != i as u8)
+        {
+            // Use SIMD-optimized single character replacement
+            process_single_char_replace(input, output, source, target);
+        } else {
+            // Standard translation using table lookup
+            output.extend(input.iter().map(|&b| self.translation_table[b as usize]));
+        }
+    }
+}
+
 #[derive(Debug, Clone)]
 pub struct SqueezeOperation {
     squeeze_table: [bool; 256],
@@ -683,7 +726,7 @@ where
 {
     const BUFFER_SIZE: usize = 32768; // Large buffer for better throughput
     let mut buf = [0; BUFFER_SIZE];
-    let mut output_buf = Vec::with_capacity(buf.len());
+    let mut output_buf = Vec::with_capacity(BUFFER_SIZE);
 
     loop {
         let length = match input.read(&mut buf[..]) {
@@ -701,21 +744,28 @@ where
             }
         }
 
-        #[cfg(not(target_os = "windows"))]
-        output
-            .write_all(&output_buf)
-            .map_err_context(|| translate!("tr-error-write-error"))?;
-
-        // SIGPIPE is not available on Windows.
-        #[cfg(target_os = "windows")]
-        if let Err(err) = output.write_all(&output_buf) {
-            if err.kind() == std::io::ErrorKind::BrokenPipe {
-                std::process::exit(13);
-            } else {
-                return Err(err.map_err_context(|| translate!("tr-error-write-error")));
-            }
+        if !output_buf.is_empty() {
+            crate::simd::write_output(output, &output_buf)?;
         }
     }
 
     Ok(())
 }
+
+/// Platform-specific flush operation
+#[inline]
+pub fn flush_output<W: Write>(output: &mut W) -> UResult<()> {
+    #[cfg(not(target_os = "windows"))]
+    return output
+        .flush()
+        .map_err_context(|| translate!("tr-error-write-error"));
+
+    #[cfg(target_os = "windows")]
+    match output.flush() {
+        Ok(()) => Ok(()),
+        Err(err) if err.kind() == std::io::ErrorKind::BrokenPipe => {
+            std::process::exit(13);
+        }
+        Err(err) => Err(err.map_err_context(|| translate!("tr-error-write-error"))),
+    }
+}

src/uu/tr/src/simd.rs

@@ -0,0 +1,108 @@
+// This file is part of the uutils coreutils package.
+//
+// For the full copyright and license information, please view the LICENSE
+// file that was distributed with this source code.
+
+//! I/O processing infrastructure for tr operations with SIMD optimizations
+
+use crate::operation::ChunkProcessor;
+use std::io::{BufRead, Write};
+use uucore::error::{FromIo, UResult};
+use uucore::translate;
+
+/// Helper to detect single-character operations for optimization
+pub fn find_single_change<T, F>(table: &[T; 256], check: F) -> Option<(u8, T)>
+where
+    F: Fn(usize, &T) -> bool,
+    T: Copy,
+{
+    let matches: Vec<_> = table
+        .iter()
+        .enumerate()
+        .filter_map(|(i, val)| check(i, val).then_some((i as u8, *val)))
+        .take(2)
+        .collect();
+
+    (matches.len() == 1).then(|| matches[0])
+}
+
+/// SIMD-optimized single character replacement
+#[inline]
+pub fn process_single_char_replace(
+    input: &[u8],
+    output: &mut Vec<u8>,
+    source_char: u8,
+    target_char: u8,
+) {
+    let count = bytecount::count(input, source_char);
+    if count == 0 {
+        output.extend_from_slice(input);
+    } else if count == input.len() {
+        output.resize(output.len() + input.len(), target_char);
+    } else {
+        output.extend(
+            input
+                .iter()
+                .map(|&b| if b == source_char { target_char } else { b }),
+        );
+    }
+}
+
+/// SIMD-optimized delete operation for single character
+pub fn process_single_delete(input: &[u8], output: &mut Vec<u8>, delete_char: u8) {
+    let count = bytecount::count(input, delete_char);
+    if count == 0 {
+        output.extend_from_slice(input);
+    } else if count < input.len() {
+        output.extend(input.iter().filter(|&&b| b != delete_char).copied());
+    }
+    // If count == input.len(), all deleted, output nothing
+}
+
+/// Unified I/O processing for all operations
+pub fn process_input<R, W, P>(input: &mut R, output: &mut W, processor: &P) -> UResult<()>
+where
+    R: BufRead,
+    W: Write,
+    P: ChunkProcessor + ?Sized,
+{
+    const BUFFER_SIZE: usize = 32768;
+    let mut buf = [0; BUFFER_SIZE];
+    let mut output_buf = Vec::with_capacity(BUFFER_SIZE);
+
+    loop {
+        let length = match input.read(&mut buf[..]) {
+            Ok(0) => break,
+            Ok(len) => len,
+            Err(e) if e.kind() == std::io::ErrorKind::Interrupted => continue,
+            Err(e) => return Err(e.map_err_context(|| translate!("tr-error-read-error"))),
+        };
+
+        output_buf.clear();
+        processor.process_chunk(&buf[..length], &mut output_buf);
+
+        if !output_buf.is_empty() {
+            write_output(output, &output_buf)?;
+        }
+    }
+
+    Ok(())
+}
+
+/// Helper function to handle platform-specific write operations
+#[inline]
+pub fn write_output<W: Write>(output: &mut W, buf: &[u8]) -> UResult<()> {
+    #[cfg(not(target_os = "windows"))]
+    return output
+        .write_all(buf)
+        .map_err_context(|| translate!("tr-error-write-error"));
+
+    #[cfg(target_os = "windows")]
+    match output.write_all(buf) {
+        Ok(()) => Ok(()),
+        Err(err) if err.kind() == std::io::ErrorKind::BrokenPipe => {
+            std::process::exit(13);
+        }
+        Err(err) => Err(err.map_err_context(|| translate!("tr-error-write-error"))),
+    }
+}

src/uu/tr/src/tr.rs

@@ -4,18 +4,20 @@
 // file that was distributed with this source code.
 
 mod operation;
+mod simd;
 mod unicode_table;
 
 use clap::{Arg, ArgAction, Command, value_parser};
 use operation::{
     DeleteOperation, Sequence, SqueezeOperation, SymbolTranslator, TranslateOperation,
-    translate_input,
+    flush_output, translate_input,
 };
+use simd::process_input;
 use std::ffi::OsString;
-use std::io::{Write, stdin, stdout};
+use std::io::{stdin, stdout};
 use uucore::LocalizedCommand;
 use uucore::display::Quotable;
-use uucore::error::{FromIo, UResult, USimpleError, UUsageError};
+use uucore::error::{UResult, USimpleError, UUsageError};
 use uucore::fs::is_stdin_directory;
 #[cfg(not(target_os = "windows"))]
 use uucore::libc;
@@ -135,7 +137,7 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
             translate_input(&mut locked_stdin, &mut locked_stdout, op)?;
         } else {
             let op = DeleteOperation::new(set1);
-            translate_input(&mut locked_stdin, &mut locked_stdout, op)?;
+            process_input(&mut locked_stdin, &mut locked_stdout, &op)?;
         }
     } else if squeeze_flag {
         if sets_len == 1 {
@@ -149,21 +151,10 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
         }
     } else {
         let op = TranslateOperation::new(set1, set2)?;
-        translate_input(&mut locked_stdin, &mut locked_stdout, op)?;
+        process_input(&mut locked_stdin, &mut locked_stdout, &op)?;
     }
 
-    #[cfg(not(target_os = "windows"))]
-    locked_stdout
-        .flush()
-        .map_err_context(|| translate!("tr-error-write-error"))?;
-
-    // SIGPIPE is not available on Windows.
-    #[cfg(target_os = "windows")]
-    match locked_stdout.flush() {
-        Ok(()) => {}
-        Err(err) if err.kind() == std::io::ErrorKind::BrokenPipe => std::process::exit(13),
-        Err(err) => return Err(err.map_err_context(|| translate!("tr-error-write-error"))),
-    }
+    flush_output(&mut locked_stdout)?;
 
     Ok(())
 }