EZAMA\jaroWinklerDistance

Complexity

Total Complexity

16

Size/Duplication

Total Lines	71
Duplicated Lines	0 %

Importance

Changes

0

5 Methods

Rating	Name	Duplication	Size	Complexity
A	prepareJaroWinkler()	0	12	1
A	jaroWinkler()	0	12	4
A	getJWDistance()	0	16	3
A	_jwMatches()	0	12	5
A	jwMatches()	0	5	3

<?php

/**
*
* @Name : similar-text
* @Programmer : Akpé Aurelle Emmanuel Moïse Zinsou
* @Date : 2019-04-01
* @Released under : https://github.com/manuwhat/similar-text/blob/master/LICENSE
* @Repository : https://github.com/manuwhat/similar
*
**/


namespace EZAMA{
    class jaroWinklerDistance extends distance
    {
        public static function jaroWinkler($a, $b, $round = 2)
        {
            if (!is_string($a) || !is_string($b)) {
                return false;
            }
            static $distance = array();
            static $previous = array();
            if (array($a, $b) === $previous) {
                return $distance;
            }
            $previous = array($a, $b);
            return self::getJWDistance($a, $b, $distance, $round);
        }
        
        
        
        private static function getJWDistance(&$a, &$b, &$distance, $round)
        {
            extract(self::prepareJaroWinkler($a, $b));
            for ($i = 0, $min = min(count((array) $a), count((array) $b)), $t = 0; $i < $min; $i++) {
                if ($a[$i] !== $b[$i]) {
                    $t++;
                }
            }
            $t /= 2;
            $distance['jaro'] = 1 / 3 * ($corresponding / $ca + $corresponding / $cb + ($corresponding - $t) / $corresponding);
            $distance['jaro-winkler'] = $distance['jaro'] + (min($longCommonSubstr, 4) * 0.1 * (1 - $distance['jaro']));
            $distance = array_map(function($v) use ($round) {
                return round($v, $round);
            }, $distance);
            
            return $distance;
        }
        
        private static function prepareJaroWinkler(&$a, &$b)
        {
            $a = self::split($a);
            $b = self::split($b);
            $transpositions = array('a'=>array(), 'b'=>array(), 'corresponding'=>0, 'longCommonSubstr'=>0, 'ca'=>count((array) $a), 'cb'=>count((array) $b));
            $Δ = max($transpositions['ca'], $transpositions['cb']) / 2 - 1;
            self::jwMatches($a, $b, $transpositions, $Δ);
            ksort($transpositions['a']);
            ksort($transpositions['b']);
            $transpositions['a'] = array_values($transpositions['a']);
            $transpositions['b'] = array_values($transpositions['b']);
            return $transpositions;
        }
        
        private static function jwMatches(&$a, &$b, &$transpositions, $Δ)
        {
            foreach ($a as $ind=>$chr) {
                foreach ($b as $index=>$char) {
                    self::_jwMatches($chr, $char, $index, $ind, $transpositions, $Δ);
                }
            }
        }
        
        private static function _jwMatches($chr, $char, $index, $ind, &$transpositions, $Δ)
        {
            if ($chr === $char && (abs($index - $ind) <= $Δ)) {
                if ($ind !== $index) {
                    $transpositions['a'][$ind] = $chr;
                    $transpositions['b'][$index] = $char;
                } else {
                    if ($ind - 1 <= $transpositions['longCommonSubstr']) {
                        $transpositions['longCommonSubstr']++;
                    }
                }
                $transpositions['corresponding']++;
            }
        }
    }
    
}