README

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RLE URL Encoder/Decoder
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Author: 	Dino Beslagic (pp19dd at gmail.com)
Homepage: 	http://pp19dd.com/rle-url/
About:		RLE URL encoder is a tiny PHP and JavaScript library that helps
			encode or decode long query strings (ex: country checkboxes) into
			short predictable string with a simple run-length encoding algorithm

This library is intended to help shrink long URLs from something like:
?country[]=Algeria&country[]=Angola&country[]=Barbados... (and 100s more)
into a predictable, short-encoded version such as: ?c=a81ja104ja11

Notes:
	*	User needs to encode each checkbox as a 1 or 0, ex: 111010101110101
		And maintain forward-reverse relationship as they like
	*	The library will also decode ?c=a81ja104ja11 into a reversible set of values
	*	There is a compatible JavaScript version of this library


How it works, simple version:

	If input string is "01111000011"
	
	Single "0" will be encoded as "n"
	Single "1" will be encoded as "j"
	Repeat "11" will be encoded as "B"
	Repeat "00" will be encoded as "b"
	Any repetitions of 1 or 0 longer than 2 characters will be encoded as:
	
		"A*"	Where A/a represents a 1/0 (repetition prefix)
		"a*"	and * is number of times to repeat that prefix
				example: A43 (43 1's)   or a33 (33 0's)

	Thus, output string for this example should be "ba4b34a2"
	
	URL-length savings is achieved with much longer strings

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USAGE EXAMPLE
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STEP 1:	scan your checkboxes and store them into a string as 1's and 0's
		Where 1/0 represents a checked state: true/false. for example:
		
		var to_encode = "";
		$(".countries input[type=checkbox]").each( function( i, e ) {
			to_encode += this.checked ? '1' : '0';
		});
		
		// to_encode should look like '1101010101000000101101010101';


STEP 2: encode the string

		var RLE_URL = new RLE_URL();
		var countries = RLE_URL.encode(to_encode);
		
		// countries should look something like a81ja104ja11
		window.location = '?countries=' + countries;


STEP 3: if you're reversing the string

		var RLE_URL = new RLE_URL();
		var parms = window.location.toString().match(/countries=(.*)/i);
		var to_decode = RLE_URL.decode( parms[1] );


STEP 4: re-populate checkboxes in a form

		$(".countries input[type=checkbox]").each( function( i, e ) {
			this.checked = to_decode.substr(i,1) == '1' ? true : false;
		});

It is up to you to manage forward/reverse lookups for values and ensure that
they're scanned in proper and consistent order. Variants of this quick jQuery
scanning / encoding routine can utilize server-side ID numbers.


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LICENSE
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No license, so anything goes.  However, short attribution would be polite.

Use this library at own risk.
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