read from stdin if filename is missing

1 files changed, 8 insertions, 7 deletions

diff --git a/src/main.rs b/src/main.rs
index da0e599..fb030d0 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,20 +1,20 @@
+use std::io::BufReader;
 use std::{env, fs::File, io::Read};
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     const CHUNK_SIZE: usize = 8;
+    let mut file: Box<dyn Read>;
 
-    let filename = env::args().nth(1).unwrap_or_default();
-    if filename.is_empty() {
-        eprintln!("error missing filename");
-        return Ok(());
-    }
+    file = if let Some(filename) = env::args().nth(1) {
+        Box::new(BufReader::new(File::open(&filename)?))
+    } else {
+        Box::new(BufReader::new(std::io::stdin()))
+    };
 
-    let mut file = File::open(&filename)?;
     let mut chunk = Vec::with_capacity(CHUNK_SIZE);
     let mut idx = 0;
 
     while {
-        chunk.clear();
         file.by_ref()
             .take(CHUNK_SIZE as u64)
             .read_to_end(&mut chunk)?
@@ -31,6 +31,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
         // write ascii
         println!("{}", String::from_utf8_lossy(&chunk).replace('\n', "⏎"));
         idx += CHUNK_SIZE;
+        chunk.clear();
     }
 
     Ok(())