perf(factor): optimize output throughput using itoa

src/uu/factor/Cargo.toml

@@ -19,6 +19,7 @@ num-traits = { workspace = true } # used in src/numerics.rs, which is included b
 
 [dependencies]
 clap = { workspace = true }
+itoa = { workspace = true }
 num-traits = { workspace = true }
 uucore = { workspace = true }
 num-bigint = { workspace = true }

src/uu/factor/src/factor.rs

@@ -85,15 +85,24 @@ fn write_result_u64(
     print_exponents: bool,
 ) -> io::Result<()> {
     write!(w, "{x}:")?;
+
+    let mut buf = itoa::Buffer::new();
     for (factor, n) in factorization {
+        let factor_str = buf.format(factor);
+
         if print_exponents {
+            w.write_all(b" ")?;
+            w.write_all(factor_str.as_bytes())?;
+
             if n > 1 {
-                write!(w, " {factor}^{n}")?;
-            } else {
-                write!(w, " {factor}")?;
+                w.write_all(b"^")?;
+                w.write_all(buf.format(n).as_bytes())?;
             }
         } else {
-            w.write_all(format!(" {factor}").repeat(n).as_bytes())?;
+            for _ in 0..n {
+                w.write_all(b" ")?;
+                w.write_all(factor_str.as_bytes())?;
+            }
         }
     }
     writeln!(w)?;
@@ -107,16 +116,26 @@ fn write_result_u128(
     factorization: BTreeMap<u128, usize>,
     print_exponents: bool,
 ) -> io::Result<()> {
-    write!(w, "{x}:")?;
+    let mut buf = itoa::Buffer::new();
+    w.write_all(buf.format(*x).as_bytes())?;
+    w.write_all(b":")?;
+
     for (factor, n) in factorization {
+        let factor_str = buf.format(factor);
+
         if print_exponents {
+            w.write_all(b" ")?;
+            w.write_all(factor_str.as_bytes())?;
+
             if n > 1 {
-                write!(w, " {factor}^{n}")?;
-            } else {
-                write!(w, " {factor}")?;
+                w.write_all(b"^")?;
+                w.write_all(buf.format(n).as_bytes())?;
             }
         } else {
-            w.write_all(format!(" {factor}").repeat(n).as_bytes())?;
+            for _ in 0..n {
+                w.write_all(b" ")?;
+                w.write_all(factor_str.as_bytes())?;
+            }
         }
     }
     writeln!(w)?;
@@ -139,7 +158,9 @@ fn write_result_big_uint(
                 write!(w, " {factor}")?;
             }
         } else {
-            w.write_all(format!(" {factor}").repeat(n).as_bytes())?;
+            for _ in 0..n {
+                write!(w, " {factor}")?;
+            }
         }
     }
     writeln!(w)?;

src/uu/numfmt/src/numfmt.rs

@@ -341,9 +341,9 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
 }
 
 pub fn uu_app() -> Command {
-    Command::new(uucore::util_name())
+    Command::new(util_name())
         .version(uucore::crate_version!())
-        .help_template(uucore::localized_help_template(uucore::util_name()))
+        .help_template(uucore::localized_help_template(util_name()))
         .about(translate!("numfmt-about"))
         .after_help(translate!("numfmt-after-help"))
         .override_usage(format_usage(&translate!("numfmt-usage")))