read 16 KiB at once

Author: oech3

src/uu/cat/src/cat.rs

@@ -482,12 +482,11 @@ fn write_fast<R: FdReadable>(handle: &mut InputHandle<R>) -> CatResult<()> {
     #[cfg(any(target_os = "linux", target_os = "android"))]
     {
         // splice is slow for small files (https://github.com/uutils/coreutils/issues/10832)
-        const SPLICE_THRESHOLD: u64 = 16 * 1024;
-        let copied = io::copy(
-            &mut handle.reader.by_ref().take(SPLICE_THRESHOLD),
-            &mut stdout_lock,
-        )?;
-        if copied < SPLICE_THRESHOLD {
+        const SPLICE_THRESHOLD: usize = 16 * 1024;
+        let mut buf = [0; SPLICE_THRESHOLD];
+        let n = handle.reader.read(&mut buf)?;
+        stdout_lock.write_all(&buf[..n])?;
+        if n < SPLICE_THRESHOLD {
             stdout_lock.flush()?;
             return Ok(());
         }
@@ -498,7 +497,7 @@ fn write_fast<R: FdReadable>(handle: &mut InputHandle<R>) -> CatResult<()> {
     }
     // If we're not on Linux or Android, or the splice() call failed,
     // fall back on slower writing.
-    let mut buf = [0; 1024 * 64];
+    let mut buf = vec![0; 1024 * 64];
     loop {
         match handle.reader.read(&mut buf) {
             Ok(n) => {