bc.scala

import java.io._
import java.nio._

val f = new File("/dev/zero")

val size = 10000
val count = 100000

def readUsingInputStream() {
    val is = new FileInputStream(f)
    val b = new Array[Byte](size)
    for (i <- 1 to count) {
        val c = is.read(b)
        if (c != size)
            throw new Exception()
    }
    is.close()
}

def readUsingByteChannel() {
    val is = new FileInputStream(f)
    val c = is.getChannel
    val b = ByteBuffer.allocateDirect(size)
    for (i <- 1 to count) {
        c.read(b)
        if (b.position != size)
            throw new Exception()
        b.rewind()
    }
    is.close()
}

def profile(what: String)(action: => Unit) = {
    val start = System.currentTimeMillis()
    action
    val delta = System.currentTimeMillis() - start
    println(what + ": " + delta)
}

while (true) {
    profile("readUsingByteChannel")(readUsingByteChannel())
    profile("readUsingInputStream")(readUsingInputStream())
}

println("$")

// vim: set ts=4 sw=4 et:

/*

outputs:

readUsingByteChannel: 132
readUsingInputStream: 254
readUsingByteChannel: 144
readUsingInputStream: 253
readUsingByteChannel: 133
readUsingInputStream: 251
readUsingByteChannel: 133
readUsingInputStream: 251
readUsingByteChannel: 132
readUsingInputStream: 300
readUsingByteChannel: 132
readUsingInputStream: 254

*/