Read a file using Stream (Scala)

read-a-file-using-stream.scala

import java.io.File
import java.io.FileInputStream

case class Chunk(length: Int, bytes: Array[Byte])

def fileContentStream(fileIn: FileInputStream): Stream[Chunk] = {
  val bytes = Array.fill[Byte](1024)(0)
  val length = fileIn.read(bytes)
  Chunk(length, bytes) #:: fileContentStream(fileIn)
}

def usingFileInput[T](filename: String)(f: (Stream[Chunk]) => T): T = {
  val fileInputStream = new FileInputStream(new File(filename))
  val stream = fileContentStream(fileInputStream) takeWhile { chunk => chunk.length > 0 }
  val result = f(stream)
  fileInputStream.close()
  result
}

val file = new File("/Users/mumoshu/Pictures/512.png")
val fileIn = new FileInputStream(file)

in(fileIn) filter { chunk => chunk._2 > 0 } foreach { chunk => chunk._2 }

I was trying to run this code of yours but I get an error. Compiler doesn't recognises 'in'. Could you please explain what 'in' is in your code?

the returned value of fileContentStream() should be
if (length == 0) Stream.empty else Chunk(length, bytes) #:: fileContentStream(fileIn)

This is a nice implementation, but given that Stream employs memoization behind the scenes, wouldn't you potentially run into memory issues with this approach and therefore want to use Iterator instead?