ACE3/addons/common/functions/fnc_stringCompare.sqf

/**
 * fn_stringCompare.sqf
 * @Descr: Determines whether one string matches another and how many characters match. Case insensitive.
 * @Author: bovine3dom
 *
 * @Arguments: [stringA STRING, stringB STRING]
 * @Return: NUMBER Number of matching characters
 * @PublicAPI: true
 */

#include "script_component.hpp"

private ["_searchTerm", "_string", "_arraySearchTerm", "_arrayString", "_sizeSearchTerm", "_sizeString", "_matchingCharacters", "_searchIterator", "_targetIterator"];
_string = toLower (_this select 0); // removes case sensitivity
_searchTerm = toLower (_this select 1);


_arraySearchTerm = toArray _searchTerm; // splits string into array of unicode decimals
_arrayString = toArray _string;
_sizeSearchTerm = count _arraySearchTerm; // We only measure the array once
_sizeString = count _arrayString;


_matchingCharacters = 0;
_targetIterator = 0;
_searchIterator = 0;
while {(_searchIterator < _sizeSearchTerm) && (_targetIterator < _sizeString)} do { // Prevents us from going out of bounds
    if ((_arraySearchTerm select _searchIterator) == (_arrayString select _targetIterator)) then { // If we have a match, start looking for the next character in the search term
        _matchingCharacters = _matchingCharacters + 1;
        _searchIterator = _searchIterator + 1
    };
    _targetIterator = _targetIterator + 1; // Look at the next character in the string
};

_matchingCharacters