#!/usr/bin/env node

// A minimal implementation of wc -c [1], which counts the number of bytes in an
// input stream. (This is a toy example: fs.stat [2] would be much, much faster
// for normal files, though this approach is still useful for streaming inputs
// like stdin.)
//
// Since `flow` is only called after the reader is filled, reader.read is
// guaranteed to return non-null when the reader has not yet ended. And since
// reader.read is called with no length argument, it is guaranteed to return
// null when the reader has ended.
//
// [1] https://en.wikipedia.org/wiki/Wc_(Unix)
// [2] http://nodejs.org/api/fs.html#fs_fs_stat_path_callback

var rw = require("../");

var reader = rw.fileReader(process.argv[2] || "/dev/stdin"),
    count = 0;

reader.fill(function flow(error) {
  if (error) throw error;
  if (reader.ended) return console.log(count);
  count += reader.read().length;
  reader.fill(flow);
});