I ♥ Alfred: Code execution extensions

ExtensionI’m a really big fan of Alfred, and lately I’ve found it really useful for running tiny little snippets of code — whether it’s to quickly URL decode a string, or remind myself of how C integer-to-float conversion behaves, I find myself using these little extensions I put together quite frequently.

Here’re two workflows I use to run PHP code (one which just executes it and shows the result in Growl, and one which copies the result to the clipboard), and a workflow that runs a snippet of C code. Of course, it wouldn’t take much to make workflows for many other languages, too.

Alfred 2 workflows

Now with live results! Hit enter to copy result to clipboard.

Run C Code.alfredworkflow

Run PHP Code.alfredworkflow

Older, Alfred 1 extensions:

Execute PHP Code.alfredextension

Execute PHP Code, Copy Result.alfredextension

Run C code.alfredextension

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Avoiding duplicate symbol issues when using common utilities within a static library

Screen Shot 2012 04 15 at 14 03 28I’m working on two projects right now that have static library products, to be given to other developers to use in their projects: Audiobus and The Amazing Audio Engine. In both cases, I’m making quite heavy use of my circular buffer code, TPCircularBuffer, which would result in duplicate symbol errors if the static library were linked with another project that used it.

In case the solution was useful to others, here’s how I worked around it: Use the preprocessor to rename the symbols automatically during the build phase.

This is done by adding a series of -DOldSymbol=NewSymbol flags to the ‘Other C Flags’ build setting – like -DTPCircularBuffer=ABCircularBuffer, for instance.

No more symbol conflicts.

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An Xcode 4 template to create universal static libraries

I’ve created an Xcode 4 project template to create universal (armv6, armv7 and simulator) static libraries for iOS, based on Adam Martin’s script:

iOS-Universal-Library-Template

The existing static library template provided with Xcode only builds one architecture, which is not particularly suitable for distribution. A number of people have created scripts to create universal libraries, which require some mucking around with Xcode target settings to use.

This template draws on this work to provide all that is required to produce universal libraries – just select the ‘Universal Static Library’ type in the New Project/New Target dialog, and you’re all set.

Universal static library

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The Amazing Audio Engine: Funky Remote IO-based Core Audio Engine Coming Soon

The Amazing Audio EngineHuzzah! I’m announcing a new project which will be launching over the next couple of months.

It’s called The Amazing Audio Engine, and it represents the product of years of experience with iOS audio. It’s a sophisticated iOS audio engine that lets developers skip the Core Audio learning curve, and get on with writing great software.

The tech behind this is what drives Loopy and Loopy HD, as well as the in-development Audiobus app.

Subscribe at theamazingaudioengine.com to be kept in the loop as it approaches launch time.

Some of the features:

  • Automatic mixing of multiple audio signals with per-channel volume and pan controls.
  • Built-in support for audio filtering and effects, including the ability to form complex filter chains, constructing channel groups, or even whole trees of groups, and filtering them as one composite signal.
  • Built-in support for audio input, including optional use of the Voice Processing IO unit, for automatic echo removal – great for VoIP.
  • Record or monitor the output of the whole audio system, for in-app session recording, or get the output of one channel, or any group of channels in the processing tree.
  • Support for any audio format (AudioStreamBasicDescription) that the hardware supports: Interleaved, non-interleaved, mono, stereo, 44.1kHz or any other supported sample rate, 16-bit, 8.24 fixed floating-point – whatever you need for your project.
  • Very light, efficient engine, designed from the ground up for speed. All Core Audio code is pure C; no Objective- C or BSD calls, no locks, no memory allocation.
  • Efficient mixing of input signals, using Apple’s MultiChannelMixer.
  • Fast, lock-free synchronisation mechanism, enabling developers to send messages to the main thread from the Core Audio context, and vice versa, without
    locking or memory allocation from the Core Audio thread. Message sending from the main thread is two-way, and can be asynchronous, with a response
    block, or synchronous.
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