Added testing features for buffering output, and ignoring output errors.

Fortune for reverse's current commit: Curse − 凶

.gitignore

@@ -1 +1,6 @@
 /target
+
+perf.*
+*.png
+flamegraph.svg
+vgcore.*

Cargo.toml

@@ -15,6 +15,12 @@ output-lines = []
 # Print each string escaped
 output-quoted = []
 
+# Buffer output to conserve syscalls, useful for very large inputs (can cause higher memory usage, but generally speeds output up considerably)
+buffer-output = []
+
+# Do not attempt to handle output errors
+ignore-output-errors = []
+
 [profile.release]
 opt-level = 3
 lto = "fat"

src/main.rs

@@ -17,27 +17,72 @@ fn binsearch<'a, V: ?Sized, T: PartialEq<V> + 'a>(slice: &'a [T], find: &V) -> O
 {
     match slice {
 	[ref a, pivot @ .., ref b] => {
-		match (a==find, b==find) {
-		    (true, _) => Some(a),
-		    (_, true) => Some(b),
-		    _ => binsearch(pivot, find),
-		}
+	    match (a==find, b==find) {
+		(true, _) => Some(a),
+		(_, true) => Some(b),
+		_ => binsearch(pivot, find),
+	    }
 	},
 	[ref a] if a == find => Some(a),
 	_ => None,
     }
 }
 
+fn collect_input() -> Box<dyn Iterator<Item=String> + 'static>
+{
+    if std::env::args_os().len() <= 1 {
+	use std::io::{
+	    self,
+	    BufRead,
+	};
+	// No args, collect stdin lines
+	Box::new(io::BufReader::new(io::stdin()
+				    .lock())
+		 .lines()
+		 .filter_map(Result::ok))
+    } else {
+	// Has arguments, return them
+	Box::new(std::env::args().skip(1))
+    }
+}
+
+#[inline(always)]
+fn handle_fmt_err<T>(res: std::io::Result<T>)
+{
+    #[cfg(not(feature="ignore-output-errors"))]    
+    res.expect("[!] failed to write");
+    let _ = res;
+}
+
 fn main() {
-    let mut args: Vec<String> = std::env::args().skip(1).collect();
+    let mut args: Vec<String> = collect_input().collect();
     reverse(&mut args[..]);
     //eprintln!("{:?}", binsearch(&args[..], "1")); // It works!
     #[cfg(feature="output-lines")]
     {
+	#[allow(unused_imports)]
+	use std::io::{
+	    Write, BufWriter,
+	};
+	#[cfg(feature="buffer-output")] 
+	let mut out = BufWriter::new(std::io::stdout().lock());
+	#[cfg(not(feature="buffer-output"))] 
+	let mut out = std::io::stdout().lock();
 	for x in args.iter() {
-	    #[cfg(feature="output-quoted")] println!("{:?}", x);
-	    #[cfg(not(feature="output-quoted"))] println!("{}", x);
+	    handle_fmt_err({
+		if cfg!(feature="output-quoted") {
+		    writeln!(&mut out, "{:?}", x)
+		}
+		else  {
+		    //writeln!(&mut out, "{}", x)
+		    out.write(x.as_bytes())
+			.and_then(|_| out.write(b"\n"))
+			.map(|_| {})
+		}
+	    });
 	}
+	//#[cfg(feature="buffer-output")] 
+	handle_fmt_err(out.flush());
     }
     #[cfg(not(feature="output-lines"))]
     println!("{:?}", args);