<?php

// phpcs:disable PSR1.Files.SideEffects
defined('SYSPATH') or die('No direct access allowed.');
// phpcs:enable PSR1.Files.SideEffects
/**
 * utf8::strtolower
 *
 * @package    Core
 * @author     Kohana Team
 * @copyright  (c) 2007 Kohana Team
 * @copyright  (c) 2005 Harry Fuecks
 * @license    http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt
 */
function _strtolower($str)
{
    if (SERVER_UTF8) {
        return mb_strtolower($str);
    }

    if (utf8::is_ascii($str)) {
        return strtolower($str);
    }

    static $UTF8_UPPER_TO_LOWER = null;

    if ($UTF8_UPPER_TO_LOWER === null) {
        $UTF8_UPPER_TO_LOWER = array(
            0x0041 => 0x0061, 0x03A6 => 0x03C6, 0x0162 => 0x0163, 0x00C5 => 0x00E5, 0x0042 => 0x0062,
            0x0139 => 0x013A, 0x00C1 => 0x00E1, 0x0141 => 0x0142, 0x038E => 0x03CD, 0x0100 => 0x0101,
            0x0490 => 0x0491, 0x0394 => 0x03B4, 0x015A => 0x015B, 0x0044 => 0x0064, 0x0393 => 0x03B3,
            0x00D4 => 0x00F4, 0x042A => 0x044A, 0x0419 => 0x0439, 0x0112 => 0x0113, 0x041C => 0x043C,
            0x015E => 0x015F, 0x0143 => 0x0144, 0x00CE => 0x00EE, 0x040E => 0x045E, 0x042F => 0x044F,
            0x039A => 0x03BA, 0x0154 => 0x0155, 0x0049 => 0x0069, 0x0053 => 0x0073, 0x1E1E => 0x1E1F,
            0x0134 => 0x0135, 0x0427 => 0x0447, 0x03A0 => 0x03C0, 0x0418 => 0x0438, 0x00D3 => 0x00F3,
            0x0420 => 0x0440, 0x0404 => 0x0454, 0x0415 => 0x0435, 0x0429 => 0x0449, 0x014A => 0x014B,
            0x0411 => 0x0431, 0x0409 => 0x0459, 0x1E02 => 0x1E03, 0x00D6 => 0x00F6, 0x00D9 => 0x00F9,
            0x004E => 0x006E, 0x0401 => 0x0451, 0x03A4 => 0x03C4, 0x0423 => 0x0443, 0x015C => 0x015D,
            0x0403 => 0x0453, 0x03A8 => 0x03C8, 0x0158 => 0x0159, 0x0047 => 0x0067, 0x00C4 => 0x00E4,
            0x0386 => 0x03AC, 0x0389 => 0x03AE, 0x0166 => 0x0167, 0x039E => 0x03BE, 0x0164 => 0x0165,
            0x0116 => 0x0117, 0x0108 => 0x0109, 0x0056 => 0x0076, 0x00DE => 0x00FE, 0x0156 => 0x0157,
            0x00DA => 0x00FA, 0x1E60 => 0x1E61, 0x1E82 => 0x1E83, 0x00C2 => 0x00E2, 0x0118 => 0x0119,
            0x0145 => 0x0146, 0x0050 => 0x0070, 0x0150 => 0x0151, 0x042E => 0x044E, 0x0128 => 0x0129,
            0x03A7 => 0x03C7, 0x013D => 0x013E, 0x0422 => 0x0442, 0x005A => 0x007A, 0x0428 => 0x0448,
            0x03A1 => 0x03C1, 0x1E80 => 0x1E81, 0x016C => 0x016D, 0x00D5 => 0x00F5, 0x0055 => 0x0075,
            0x0176 => 0x0177, 0x00DC => 0x00FC, 0x1E56 => 0x1E57, 0x03A3 => 0x03C3, 0x041A => 0x043A,
            0x004D => 0x006D, 0x016A => 0x016B, 0x0170 => 0x0171, 0x0424 => 0x0444, 0x00CC => 0x00EC,
            0x0168 => 0x0169, 0x039F => 0x03BF, 0x004B => 0x006B, 0x00D2 => 0x00F2, 0x00C0 => 0x00E0,
            0x0414 => 0x0434, 0x03A9 => 0x03C9, 0x1E6A => 0x1E6B, 0x00C3 => 0x00E3, 0x042D => 0x044D,
            0x0416 => 0x0436, 0x01A0 => 0x01A1, 0x010C => 0x010D, 0x011C => 0x011D, 0x00D0 => 0x00F0,
            0x013B => 0x013C, 0x040F => 0x045F, 0x040A => 0x045A, 0x00C8 => 0x00E8, 0x03A5 => 0x03C5,
            0x0046 => 0x0066, 0x00DD => 0x00FD, 0x0043 => 0x0063, 0x021A => 0x021B, 0x00CA => 0x00EA,
            0x0399 => 0x03B9, 0x0179 => 0x017A, 0x00CF => 0x00EF, 0x01AF => 0x01B0, 0x0045 => 0x0065,
            0x039B => 0x03BB, 0x0398 => 0x03B8, 0x039C => 0x03BC, 0x040C => 0x045C, 0x041F => 0x043F,
            0x042C => 0x044C, 0x00DE => 0x00FE, 0x00D0 => 0x00F0, 0x1EF2 => 0x1EF3, 0x0048 => 0x0068,
            0x00CB => 0x00EB, 0x0110 => 0x0111, 0x0413 => 0x0433, 0x012E => 0x012F, 0x00C6 => 0x00E6,
            0x0058 => 0x0078, 0x0160 => 0x0161, 0x016E => 0x016F, 0x0391 => 0x03B1, 0x0407 => 0x0457,
            0x0172 => 0x0173, 0x0178 => 0x00FF, 0x004F => 0x006F, 0x041B => 0x043B, 0x0395 => 0x03B5,
            0x0425 => 0x0445, 0x0120 => 0x0121, 0x017D => 0x017E, 0x017B => 0x017C, 0x0396 => 0x03B6,
            0x0392 => 0x03B2, 0x0388 => 0x03AD, 0x1E84 => 0x1E85, 0x0174 => 0x0175, 0x0051 => 0x0071,
            0x0417 => 0x0437, 0x1E0A => 0x1E0B, 0x0147 => 0x0148, 0x0104 => 0x0105, 0x0408 => 0x0458,
            0x014C => 0x014D, 0x00CD => 0x00ED, 0x0059 => 0x0079, 0x010A => 0x010B, 0x038F => 0x03CE,
            0x0052 => 0x0072, 0x0410 => 0x0430, 0x0405 => 0x0455, 0x0402 => 0x0452, 0x0126 => 0x0127,
            0x0136 => 0x0137, 0x012A => 0x012B, 0x038A => 0x03AF, 0x042B => 0x044B, 0x004C => 0x006C,
            0x0397 => 0x03B7, 0x0124 => 0x0125, 0x0218 => 0x0219, 0x00DB => 0x00FB, 0x011E => 0x011F,
            0x041E => 0x043E, 0x1E40 => 0x1E41, 0x039D => 0x03BD, 0x0106 => 0x0107, 0x03AB => 0x03CB,
            0x0426 => 0x0446, 0x00DE => 0x00FE, 0x00C7 => 0x00E7, 0x03AA => 0x03CA, 0x0421 => 0x0441,
            0x0412 => 0x0432, 0x010E => 0x010F, 0x00D8 => 0x00F8, 0x0057 => 0x0077, 0x011A => 0x011B,
            0x0054 => 0x0074, 0x004A => 0x006A, 0x040B => 0x045B, 0x0406 => 0x0456, 0x0102 => 0x0103,
            0x039B => 0x03BB, 0x00D1 => 0x00F1, 0x041D => 0x043D, 0x038C => 0x03CC, 0x00C9 => 0x00E9,
            0x00D0 => 0x00F0, 0x0407 => 0x0457, 0x0122 => 0x0123,
        );
    }

    $uni = utf8::to_unicode($str);

    if ($uni === false) {
        return false;
    }

    for ($i = 0, $c = count($uni); $i < $c; $i++) {
        if (isset($UTF8_UPPER_TO_LOWER[$uni[$i]])) {
            $uni[$i] = $UTF8_UPPER_TO_LOWER[$uni[$i]];
        }
    }

    return utf8::from_unicode($uni);
}