function ArrayBufferReader(arrayBuffer) {
    var that = this;

    function init(callback, onerror) {
        that.size = arrayBuffer.byteLength;
        callback();
    }

    function readUint8Array(index, length, callback, onerror) {
        callback(new Uint8Array(arrayBuffer.slice(index, index   length)));
    }

    that.size = 0;
    that.init = init;
    that.readUint8Array = readUint8Array;
}
ArrayBufferReader.prototype = new zip.Reader();
ArrayBufferReader.prototype.constructor = ArrayBufferReader;

function ArrayBufferWriter() {
    var array, that = this;

    function init(callback, onerror) {
        array = new Uint8Array();
        callback();
    }

    function writeUint8Array(arr, callback, onerror) {
        var tmpArray = new Uint8Array(array.length   arr.length);
        tmpArray.set(array);
        tmpArray.set(arr, array.length);
        array = tmpArray;
        callback();
    }

    function getData(callback) {
        callback(array.buffer);
    }

    that.init = init;
    that.writeUint8Array = writeUint8Array;
    that.getData = getData;
}
ArrayBufferWriter.prototype = new zip.Writer();
ArrayBufferWriter.prototype.constructor = ArrayBufferWriter;