NativeLongArray Class — netty Architecture

Source Code

transport-classes-kqueue/src/main/java/io/netty/channel/kqueue/NativeLongArray.java lines 27–112

final class NativeLongArray {
    private CleanableDirectBuffer memoryCleanable;
    private ByteBuffer memory;
    private long memoryAddress;
    private int capacity;
    private int size;

    NativeLongArray(int capacity) {
        this.capacity = checkPositive(capacity, "capacity");
        memoryCleanable = Buffer.allocateDirectBufferWithNativeOrder(calculateBufferCapacity(capacity));
        memory = memoryCleanable.buffer();
        memoryAddress = Buffer.memoryAddress(memory);
    }

    private static int idx(int index) {
        return index * SIZEOF_JLONG;
    }

    private static int calculateBufferCapacity(int capacity) {
        return capacity * SIZEOF_JLONG;
    }

    void add(long value) {
        reallocIfNeeded();
        if (PlatformDependent.hasUnsafe()) {
            PlatformDependent.putLong(memoryOffset(size), value);
        } else {
            memory.putLong(idx(size), value);
        }
        ++size;
    }

    void clear() {
        size = 0;
    }

    boolean isEmpty() {
        return size == 0;
    }

    int size() {
        return size;
    }

    void free() {
        memoryCleanable.clean();
        memoryAddress = 0;
    }

    long memoryAddress() {
        return memoryAddress;
    }

    long memoryAddressEnd() {
        return memoryOffset(size);
    }

    private long memoryOffset(int index) {
        return memoryAddress + idx(index);
    }

    private void reallocIfNeeded() {
        if (size == capacity) {
            // Double the capacity while it is "sufficiently small", and otherwise increase by 50%.
            int newLength = capacity <= 65536 ? capacity << 1 : capacity + capacity >> 1;
            int newCapacity = calculateBufferCapacity(newLength);
            CleanableDirectBuffer buffer = Buffer.allocateDirectBufferWithNativeOrder(newCapacity);
            // Copy over the old content of the memory and reset the position as we always act on the buffer as if
            // the position was never increased.
            memory.position(0).limit(size);
            buffer.buffer().put(memory);
            buffer.buffer().position(0);

            memoryCleanable.clean();
            memoryCleanable = buffer;
            memory = buffer.buffer();
            memoryAddress = Buffer.memoryAddress(memory);
            capacity = newLength;
        }
    }