MobWritePatcher

MobWritePatcher.php

<?php
function MobWritePatcher($text, $patch) {
	$pointer = 0;
	
	foreach(explode("\t", $patch) as $step) {
		$modifier = substr($step, 0, 1);
		$argument = substr($step, 1);
		
		switch($modifier) {
			case '=':
				$diff_length = $argument;
				break;
			case '+':
				$diff_length = strlen($argument);
				$text = substr($text, 0, $pointer).$argument.substr($text, $pointer);
				break;
			case '-':
				$diff_length = 0;
				$text = substr_replace($text, '', $pointer, $argument);
				break;
		}
		
		$pointer += $diff_length;
	}
	
	return strlen($text) == $pointer ? $text : FALSE;
}

$text = 'Hej hopp tjo falleralla';
$patch = '=4	+kaka 	-3	=16';

if( $result = MobWritePatcher($text, $patch))
	print $result;
else
	print 'Checksum failed';