public class RAMDisk implements BlockDevice {

  private static final int DEFAULTBLOCKSIZE = 256,

        DEFAULTNUMBEROFBLOCKS = 200;

  private int blockSize, numberOfBlocks;

  private byte[] storage;

  public RAMDisk () {

    this (DEFAULTBLOCKSIZE, DEFAULTNUMBEROFBLOCKS);

  }

  public RAMDisk (int b, int n) {

    blockSize = b;

    numberOfBlocks = n;

    storage = new byte[blockSize * numberOfBlocks];

  }

  public void readBlock (byte[] buffer, int block) {

    int blockindex = block * blockSize;

    for (int i = 0; i < blockSize; i++)

      buffer[i] = storage[blockindex + i];

  }

  public void writeBlock (byte[] buffer, int block) {

    int blockindex = block * blockSize;

      for (int i = 0; i < blockSize; i++)

        storage[blockindex + i] = buffer[i]; 

  }

  public int getBlockSize () {

    return blockSize;

  }

  public int getNumberOfBlocks () {

    return numberOfBlocks;

  }

}