Augusto Pascutti augustohp

Why objects (usually) use less memory than arrays in PHP

This is just a small post in response to [this tweet][tweet] by Julien Pauli (who by the way is the release manager for PHP 5.5). In the tweet he claims that objects use more memory than arrays in PHP. Even though it can be like that, it's not true in most cases. (Note: This only applies to PHP 5.4 or newer.)

The reason why it's easy to assume that objects are larger than arrays is because objects can be seen as an array of properties and a bit of additional information (like the class it belongs to). And as array + additional info > array it obviously follows that objects are larger. The thing is that in most cases PHP can optimize the array part of it away. So how does that work?

The key here is that objects usually have a predefined set of keys, whereas arrays don't:

Basics

<?php

use Respect\Relational\Mapper;
use Respect\Data\Collections\Collection;

//Configuring

Apple,

You are a company I learned to love and hate. In that same order.

I love the way you try to reach excellence in everything you do
I hate the way you try to fuck everyone else who tries to do same

Things I (still) love

The MacBook (track pad) is a great piece of hardware, sadly it is not one-of-a-kind anymore. Even more sad is that all other (great) options do not try to hold you on all kind of accessories and stuff, although it still bearable for an old time customer.

In August 2007 a hacker found a way to expose the PHP source code on facebook.com. He retrieved two files and then emailed them to me, and I wrote about the issue:

http://techcrunch.com/2007/08/11/facebook-source-code-leaked/

It became a big deal:

http://www.techmeme.com/070812/p1#a070812p1

The two files are index.php (the homepage) and search.php (the search page)

The new Secure Password Hashing API in PHP 5.5

The [RFC for a new simple to use password hashing API][rfc] has just been accepted for PHP 5.5. As the RFC itself is rather technical and most of the sample codes are something you should not use, I want to give a very quick overview of the new API:

Why do we need a new API?

Everybody knows that you should be hashing their passwords using bcrypt, but still a surprising number of developers uses insecure md5 or sha1 hashes (just look at the recent password leaks). One of the reasons for this is that the crypt() API is ridiculously hard to use and very prone to programming mistakes.

	/! normalize.css v2.1.3 \| MIT License \| git.io/normalize /

	/* ==========================================================================
	HTML5 display definitions
	========================================================================== */

	/**
	* Correct `block` display not defined in IE 8/9.
	*/

	GET /products HTTP/1.1
	Host: example.com

	HTTP/1.1 200 Ok
	Content-Type: text/html;charset=utf-8
	<!doctype html>
	<title>All Products</title>
	<h1>Products</h1>
	<ul>
	<li><a rel="item" href="/products/1">Product 1</a></li>

	// Just before switching jobs:
	// Add one of these.
	// Preferably into the same commit where you do a large merge.
	//
	// This started as a tweet with a joke of "C++ pro-tip: #define private public",
	// and then it quickly escalated into more and more evil suggestions.
	// I've tried to capture interesting suggestions here.
	//
	// Contributors: @r2d2rigo, @joeldevahl, @msinilo, @_Humus_,
	// @YuriyODonnell, @rygorous, @cmuratori, @mike_acton, @grumpygiant,

	<?php

	// PHP Self Stats

	/*
	* get_loaded_extensions() returns all the extension names
	* currently loaded.
	*
	* Using array_intersect(), we can get only the extensions
	* we want from those which are really available.

	#!/usr/bin/env php
	<?php

	/**
	* Convert SimpleTest tests to PHPUnit, mocks to Mockery.
	*
	* Caveats:
	* - Assertion + return value can't be combined automatically
	*/