source: gs3-extensions/web-audio/trunk/js-mad/sink.js-master/src/utils/proxy.js@ 28388

(function (Sink) {

function Proxy (bufferSize, channelCount) {
    Sink.EventEmitter.call(this);

    this.bufferSize     = isNaN(bufferSize) || bufferSize === null ? this.bufferSize : bufferSize;
    this.channelCount   = isNaN(channelCount) || channelCount === null ? this.channelCount : channelCount;

    var self = this;
    this.callback = function () {
        return self.process.apply(self, arguments);
    };

    this.resetBuffer();
}

Proxy.prototype = {
    buffer: null,
    zeroBuffer: null,
    parentSink: null,
    bufferSize: 4096,
    channelCount: 2,
    offset: null,

    resetBuffer: function () {
        this.buffer = new Float32Array(this.bufferSize);
        this.zeroBuffer = new Float32Array(this.bufferSize);
    },

    process: function (buffer, channelCount) {
        if (this.offset === null) {
            this.loadBuffer();
        }

        for (var i=0; i<buffer.length; i++) {
            if (this.offset >= this.buffer.length) {
                this.loadBuffer();
            }

            buffer[i] = this.buffer[this.offset++];
        }
    },

    loadBuffer: function () {
        this.offset = 0;
        Sink.memcpy(this.zeroBuffer, 0, this.buffer, 0);
        this.emit('audioprocess', [this.buffer, this.channelCount]);
    }
};

Sink.Proxy = Proxy;

/**
 * Creates a proxy callback system for the sink instance.
 * Requires Sink utils.
 *
 * @method Sink
 * @method createProxy
 *
 * @arg {Number} !bufferSize The buffer size for the proxy.
*/
Sink.prototype.createProxy = function (bufferSize) {
    var proxy       = new Sink.Proxy(bufferSize, this.channelCount);
    proxy.parentSink    = this;

    this.on('audioprocess', proxy.callback);

    return proxy;
};

}(this.Sink));