Scala Native PulseAudio example

Main.scala

import libpulse.functions.pa_simple_new
import libpulse.functions.pa_simple_write
import libpulse.functions.pa_simple_free
import libpulse.types.pa_sample_spec
import libpulse.types.pa_sample_format
import libpulse.types.pa_stream_direction
import libpulse.extern_functions
import scala.scalanative.unsafe
import scala.scalanative.unsafe._
import scalanative.unsigned.UnsignedRichInt
import scalanative.unsigned.ULong
import java.nio.file.Files
import java.nio.file.Paths

@link("pulse-simple")
object Main {

  def readPcm(): Array[Byte] =
    Files.readAllBytes(Paths.get("/home/user/Music/Recording6.pcm"))


  def makeNativeArray(input: Array[Byte])(using z: Zone): Ptr[Byte] =
    if (unsafe.sizeof[Byte] != 1.toUByte) {
      throw Exception(s"Byte size is not 1, but ${unsafe.sizeof[Byte]}. Can't proceed")
    }
    val rawSize = input.length
    val buffer = alloc[Byte](rawSize)
    for i <- 0 until rawSize
    do
      buffer(i) = input(i)
    buffer

  def main(args: Array[String]): Unit = Zone { implicit z =>
    val spec = pa_sample_spec(pa_sample_format.PA_SAMPLE_S16LE, 44100.toUInt, 2.toUByte)
    val pa_simple = pa_simple_new(
      null,
      c"ScalaNativeApp",
      pa_stream_direction.PA_STREAM_PLAYBACK,
      null,
      c"Music",
      spec,
      null,
      null,
      null
    )
    val pcmBytes = readPcm()
    val rawSize = pcmBytes.length
    val buffer = makeNativeArray(pcmBytes)
    val err = (0 : CInt).toPtr[CInt]

    val result = pa_simple_write(pa_simple, buffer, rawSize.toUInt,  err)
    if (result < 0) {
      println("error simple write")
      val code = !err
      println(s"error code: ${code}")
    } else {
      println("ok simple write")
    }
    pa_simple_free(pa_simple)
    println("Done.")
  }
}