kotlin reading from file into byte array

Question

How do I read bytes into a Byte Array? In java I used to initialize byte array as byte[] b = new byte[100] and then pass that to the corresponding method. However in Kotlin, I am unable to initialize ByteArray with how many bytes the buffer should have.

In other words, how do I use this function?: https://developer.android.com/reference/kotlin/java/io/RandomAccessFile#read(kotlin.ByteArray)

Answer 1

The easiest way is to use

File("aaa").readBytes()

That one will read the whole file into the ByteArray. But you should carefully know you have enough RAM in the heap to do so

The ByteArray can be created via ByteArray(100) call, where 100 is the size of it

For the RandomAccessFile, it is probably better to use at the readFully function, which reads exactly the requested amount of bytes.

The classic approach is possible to read a file by chunks, e.g.

    val buff = ByteArray(1230)
    File("aaa").inputStream().buffered().use { input ->
      while(true) {
        val sz = input.read(buff)
        if (sz <= 0) break

        ///at that point we have a sz bytes in the buff to process
        consumeArray(buff, 0, sz)
      }
    }