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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:

Business Models

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Tested against the WebKit git repo by entering the repo with 1 file dirty.

git diff --quiet --ignore-submodules HEAD # Will tell if there are any uncomitted changes, staged or not.
0.6 sec

git diff-index --quiet HEAD # Only tracked
2 sec

agnoster.zsh-theme

A ZSH theme optimized for people who use:

Solarized
Git
Unicode-compatible fonts and terminals (I use iTerm2 + Menlo)

For Mac users, I highly recommend iTerm 2 + Solarized Dark

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.

tmux shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname

tmux cheat sheet

(C-x means ctrl+x, M-x means alt+x)

Prefix key

The default prefix is C-b. If you (or your muscle memory) prefer C-a, you need to add this to ~/.tmux.conf:

remap prefix to Control + a

Most active GitHub users (git.io/top)

The list would not be updated for now. Don't write comments.

The count of contributions (summary of Pull Requests, opened issues and commits) to public repos at GitHub.com from Wed, 21 Sep 2022 till Thu, 21 Sep 2023.

Because of GitHub search limitations, only 1000 first users according to amount of followers are included. If you are not in the list you don't have enough followers. See raw data and source code. Algorithm in pseudocode:

githubUsers

	#!/bin/sh

	###
	# SOME COMMANDS WILL NOT WORK ON macOS (Sierra or newer)
	# For Sierra or newer, see https://github.com/mathiasbynens/dotfiles/blob/master/.macos
	###

	# Alot of these configs have been taken from the various places
	# on the web, most from here
	# https://github.com/mathiasbynens/dotfiles/blob/5b3c8418ed42d93af2e647dc9d122f25cc034871/.osx

	sudo defaults write /Library/Preferences/com.apple.windowserver DisplayResolutionEnabled -bool YES;
	sudo defaults delete /Library/Preferences/com.apple.windowserver DisplayResolutionDisabled;

	// by the way, you need to logout and log back in for this to take effect. Or at least that's what
	// Quartz Debug says. Who knows, maybe it's lying?

	// P.S. Go to [Apple menu --> System Preferences --> Displays --> Display --> Scaled] after logging
	// back in, and you'll see a bunch of "HiDPI" resolutions in the list to choose from.