PHP implement Boyer–Moore algorithm

BoyerMooreExample.php

<?php

/**
 * @param string $text      The string to search in.
 * @param string $search    The target string to search
 *
 * @return int              The start index of the search string
 */
function getStringStartIndexByBoyerMoore($text, $search) {
    $textLength = strlen($text);
    $searchLength = strlen($search);
    $table = getCharRightMinDistanceTable($search);
    $index = $searchLength - 1;
    while($index < $textLength) {
        for ($i = $index, $j = $searchLength - 1 ; $text[$i] == $search[$j] ; $i--, $j--) {
            if ($j == 0) {
                return $i;
            }
        }

        $index += isset($table[$text[$index]]) ? max($table[$text[$index]], 1) : $searchLength ;
    }
    return -1;
}

/**
 * @param string $text
 *
 * @return array
 */
function getCharRightMinDistanceTable($text) {
    $len = strlen($text);
    $table = [];
    for ($i = 0 ; $i < $len ; $i++) {
        $table[$text[$i]] = $len - $i - 1;
    }
    return $table;
}