Add command-line arguments.

src/worker.rs

@@ -0,0 +1,77 @@
+use std::io;
+use std::fs;
+use std::io::Read;
+use std::boxed::Box;
+
+// Read 1KiB of the file at a time.
+static BLOCK_SIZE:usize = 1024;
+
+pub fn work(in_path:Option<&str>, out_path:Option<&str>) -> io::Result<()>  {
+	let mut in_reader:Box<dyn io::Read> = match in_path {
+		Some(x) => {
+			let in_file = fs::File::open(x)?;
+			Box::new(io::BufReader::new(in_file))
+		},
+		None => {
+			Box::new(io::stdin())
+		},
+	};
+
+	let mut out_writer:Box<dyn io::Write> = match out_path {
+		Some(x) => {
+			let out_file = fs::File::create(x)?;
+			Box::new(io::BufWriter::new(out_file))
+		},
+		None => {
+			Box::new(io::stdout())
+		},
+	};
+
+	let mut read_buf:[u8; BLOCK_SIZE] = [0; BLOCK_SIZE];
+	let mut last_ch:char = '\0';
+	let mut tab_num = 0;
+
+	while in_reader.read(&mut read_buf)? > 0 {
+		for i in read_buf {
+			let ch = i as char;
+			match ch {
+				'[' | '{' => {
+					tab_num += 1;
+					out_writer.write(format!("{}\n", ch).as_bytes())?;
+					for _ in 0..tab_num {
+						out_writer.write(b"  ")?;
+					}
+					last_ch = ' ';
+				},
+				']' | '}' => {
+					tab_num -= 1;
+					out_writer.write(b"\n")?;
+					for _ in 0..tab_num {
+						out_writer.write(b"  ")?;
+					}
+					out_writer.write(format!("{}", ch).as_bytes())?;
+					last_ch = ch;
+				},
+				',' => {
+					out_writer.write(format!("{}\n", ch).as_bytes())?;
+					for _ in 0..tab_num {
+						out_writer.write(b"  ")?;
+					}
+					last_ch = ' ';
+				},
+				_ => {
+					let ch = ch;
+					if ch != ' ' || last_ch != ' ' {
+						out_writer.write(format!("{}", ch).as_bytes())?;
+						last_ch = ch;
+					}
+				},
+			}
+		}
+	}
+
+	out_writer.flush()?;
+
+	Ok(())
+
+}