slowcat v1.0

.gitignore

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+/target

Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "slowcat"
+version = "1.0.0"

Cargo.toml

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+[package]
+name = "slowcat"
+version = "1.0.0"
+edition = "2021"
+
+[dependencies]
+
+[profile.release]
+lto = true
+strip = true
+debug = false
+panic = "unwind"
+codegen-units = 1

rustfmt.toml

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+group_imports = "StdExternalCrate"
+imports_granularity = "Crate"
+imports_layout = "HorizontalVertical"

src/main.rs

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+use std::{
+    env,
+    io::{stdin, stdout, Read, StdoutLock, Write},
+    time::Duration,
+};
+
+static DEFAULT_HZ: u32 = 100;
+
+fn output_slow(data: &[u8], hz: u32, out: &mut StdoutLock) {
+    // write 1 byte at a time
+    data.iter().for_each(|&b| {
+        out.write_all(&[b]).unwrap();
+        out.flush().unwrap();
+
+        // sleep according to given frequency
+        std::thread::sleep(Duration::from_secs_f64(1.0 / hz as f64));
+    });
+}
+
+fn main() {
+    let hz: u32 = env::args()
+        .nth(1)
+        .map_or(DEFAULT_HZ, |s| s.parse().unwrap());
+
+    let mut out = stdout().lock();
+    let mut buf = [0u8; 8 * 1024];
+
+    // read 8k
+    while let Ok(n) = stdin().read(&mut buf) {
+        if n == 0 {
+            break; // EOF
+        }
+
+        let data = &buf[..n];
+        if hz != 0 {
+            // slow output with delay according to given frequency
+            output_slow(data, hz, &mut out);
+        } else {
+            // normal output without delay if given frequency is zero
+            out.write_all(data).unwrap();
+        }
+    }
+}