padstream.js

var Transform = require('stream').Transform;
var util = require('util');

function Padstream() {
        if (!(this instanceof Padstream))
                return new Padstream();

        Padstream.call(this);

        this._buffer = new Buffer(64);
        this._pos = 0;
}
util.inherits(Padstream, Transform);

Padstream.prototype._transform = function padTransform(chunk, encoding, done) {
        // TODO handle chunk > this._buffer.length
 
        var copied = chunk.copy(this._buffer,
                        this._pos,
                        0,
                        chunk.length - (this._buffer.length - this._pos));

        this._pos += copied;

        if (this._pos === this._buffer.length) {
                this.push(this._buffer);
                this._pos = 0;
                if (copied < chunk.length)
                        this._buffer = chunk.slice(copied);
                else
                        this._buffer = new Buffer(64);
        }
};

Padstream.prototype._flush = function padFlush(done) {
        if (this._pos > 0) {
                this._buffer.fill(0, this._pos);
                this.push(this._buffer);
                this._buffer = false;
                this._pos = false;
        }
        done();
};


srcstream.pipe(new Padstream()).pipe(client);