Configumerator

Yet another configuration file assistance library.

Why?

All the libraries I found seemed to be overkill for the simple uses that I needed. Plus, I wanted something that could easily work on both Android and non-Android Linux.

Okay, but why do I care?

You have a lot of questions for someone I've never met.

You might care if you want a simple library that converts a configuration file into a C++ class that you can then query for that configuration file's content. You might also enjoy not re-writing the same option validation code in different projects. I certainly enjoyed it.

Fine, so how do I use it?

Absolutely chuffed you asked! It goes a-litle something like this. First you install it:

Android

$ cd $NDK_MODULE_PATH
$ mkdir edu.umich.mobility
$ git clone https://github.com/brettdh/configumerator.git

then add this line to the end of your Android.mk:

$(call import-module, edu.umich.mobility/configumerator)

Don't forget to add configumerator to your LOCAL_SHARED_LIBRARIES.

Not-Android

$ git clone https://github.com/brettdh/configumerator.git
$ cd configumerator
$ make
$ sudo make install

And then you use it! Like so:

#include <configumerator.h>

Then, define a subclass of configumerator::Config that defines a setup method. This method should call some of these functions to register the names of different config options of different types:

registerBooleanOption
registerStringOption
registerDoubleOption
registerDoubleListOption

Each of these reads what it says it reads; a list of double-precision floats is delimited by spaces.

Additionally, there's registerOptionReader, which takes an option-reading function and a pointer to a set of option keys and arranges to call the reader function whenever a line in the config file matches one of the keys. The function receives two arguments -- the key and the rest of the line, as strings -- and returns nothing. It should accomplish the option-saving by modifying the Config subclass. For instance, the above register* methods are implemented using std::bind and a member function.

You probably also want to define some public accessor methods for the options you're reading in.

Speaking of reading in: you'll need to define a static method that returns an instance of your Config subclass. Your constructor will need to create a Config instance and call loadConfig(filename) on it. This will cause a few things to happen:

• Your setup method will be called
• The file will be read
• Your validate method will be called

If configumerator encounters any errors when reading the file -- for example, an option that doesn't match any that you've registered, or a numeric option that can't be parsed as a number -- it will throw a ConfigValidationError. If you need any special validation steps, implement them in validate and throw the same error. If an error occurs, loadConfig will catch the exception, print a message about the error, and then exit.