!include once #1027304 // Eclipse Collections

import java.nio.*;

import java.nio.channels.*;

// read-only, so far. should be thread-safe

// reads whole file into huge byte arrays on start

final sclass RAMByteMemory64 implements IByteMemory64, AutoCloseable {

  File file; // the file we loaded

  long size; // file size in ints

  bool bigEndian = true;

  bool debug;

  // byte buffers

  int arrayShift = 30; // each buffer is 1 GB

  int arraySize = 1 << arrayShift;

  byte[][] arrays;

  *() {}

  *(File file) {

    load(file);

  }

  void load(File file) ctex {

    this.file = file;

    size = fileSize(file);

    temp RandomAccessFile raf = newRandomAccessFile(file, "r");

    arrays = new byte[toInt(rightShift_ceil(size, arrayShift))][];

    FileChannel channel = raf.getChannel();

    print("Allocating " + n2(size) + " bytes");

    for i over arrays: {

      long pos = (long) i << arrayShift;

      int len = toInt(min(1 << arrayShift, size-pos));

      arrays[i] = new byte[len];

    }

    for i over arrays: {

      long pos = (long) i << arrayShift;

      int len = l(arrays[i]);

      print("Loading bytes " + longToHex(pos) + "-" + longToHex(pos+len) + " of " + file);

      MappedByteBuffer byteBuffer = channel.map(FileChannel.MapMode.READ_ONLY, pos, len);

      byteBuffer.get(arrays[i]);

    }

    print(size + " bytes loaded");

  }

  public void close {}

  public byte getByte(long idx) {

    rangeCheck(idx, size);

    ret arrays[(int) (idx >> arrayShift)][(((int) idx) & (arraySize-1))];

  }

  public int getInt(long idx) {

    assertTrue(+bigEndian);

    ret ubyteToInt(getByte(idx)) << 24 |

      ubyteToInt(getByte(idx+1)) << 16 |

      ubyteToInt(getByte(idx+2)) << 8 |

      ubyteToInt(getByte(idx+3));

  }

  public void set(long idx, int val) {

    checkWritable();

    fail("todo");

  }

  void checkWritable {

    fail("read-only");

  }

  public long size() {

    ret size;

  }

  public void ensureSize(int size) {

    this.size = max(this.size, size);

  }

  void importVirtual(virtual RAMByteMemory64 mem) {

    copyFields(mem, this);

  }

}