PHP - osu! Gamemode Converter

gamemode.php

<?php
/**
 * 게임모드 변환 함수
 * 레퍼런스 참조는 아래 주석.
 * https://github.com/ppy/osu-api/wiki
 * enum Mods
 * {
 *     None           = 0,
 *     NoFail         = 1,
 *     Easy           = 2,
 *     TouchDevice    = 4,
 *     Hidden         = 8,
 *     HardRock       = 16,
 *     SuddenDeath    = 32,
 *     DoubleTime     = 64,
 *     Relax          = 128,
 *     HalfTime       = 256,
 *     Nightcore      = 512, // Only set along with DoubleTime. i.e: NC only gives 576
 *     Flashlight     = 1024,
 *     Autoplay       = 2048,
 *     SpunOut        = 4096,
 *     Relax2         = 8192,  // Autopilot
 *     Perfect        = 16384, // Only set along with SuddenDeath. i.e: PF only gives 16416  
 *     Key4           = 32768,
 *     Key5           = 65536,
 *     Key6           = 131072,
 *     Key7           = 262144,
 *     Key8           = 524288,
 *     FadeIn         = 1048576,
 *     Random         = 2097152,
 *     Cinema         = 4194304,
 *     Target         = 8388608,
 *     Key9           = 16777216,
 *     KeyCoop        = 33554432,
 *     Key1           = 67108864,
 *     Key3           = 134217728,
 *     Key2           = 268435456,
 *     ScoreV2        = 536870912,
 *     LastMod        = 1073741824,
 *     KeyMod = Key1 | Key2 | Key3 | Key4 | Key5 | Key6 | Key7 | Key8 | Key9 | KeyCoop,
 *     FreeModAllowed = NoFail | Easy | Hidden | HardRock | SuddenDeath | Flashlight | FadeIn | Relax | Relax2 | SpunOut | KeyMod,
 *     ScoreIncreaseMods = Hidden | HardRock | DoubleTime | Flashlight | FadeIn
 * }
 */

/**
 * gamemode_to_str :: gamemode 값을 String 으로 반환
 * @param  int    $gamemode 모드 값 (mysql 에서 나온 값) 입력
 * @return string           데이터 출력 (osu!, Taiko, CTB, osu!mania, Unknown)
 */
function gamemode_to_str($gamemode) {
    switch ($gamemode) {
        case 0:
            return 'osu!';
        case 1:
            return 'Taiko';
        case 2:
            return 'CTB';
        case 3:
            return 'osu!mania';
        default:
            return 'Unknown';
    }
}

/**
 * mode_to_str :: mode 값을 String 으로 반환
 * @param  int    $mode 모드 값 (mysql 에서 나온 값) 입력
 * @return string       데이터 출력 (+ DT, RX, FL, SO)
 */
function mode_to_str($mode) {
    $mods = [
        'NF'      => 0x1,        // NoFail
        'EZ'      => 0x2,        // Easy
        'TD'      => 0x4,        // TouchDevice
        'HD'      => 0x8,        // Hidden
        'HR'      => 0x10,       // HardRock
        'SD'      => 0x20,       // SuddenDeath
        'DT'      => 0x40,       // DoubleTime
        'RX'      => 0x80,       // Relax
        'HF'      => 0x100,      // HalfTime
        'NC'      => 0x200,      // Nightcore
        'FL'      => 0x400,      // Flashlight
        'Auto'    => 0x800,      // Auto
        'SO'      => 0x1000,     // SpunOut
        'AP'      => 0x2000,     // Autopilot
        'PF'      => 0x4000,     // Perfect
        'K4'      => 0x8000,     // Key4
        'K5'      => 0x10000,    // Key5
        'K6'      => 0x20000,    // Key6
        'K7'      => 0x40000,    // Key7
        'K8'      => 0x80000,    // Key8
        'FadeIn'  => 0x100000,   // FadeIn
        'Random'  => 0x200000,   // Random
        'Cinema'  => 0x400000,   // Cinema
        'Target'  => 0x800000,   // Target??
        'K9'      => 0x1000000,  // Key9
        'KC'      => 0x2000000,  // KeyCoop
        'K1'      => 0x4000000,  // Key1
        'K3'      => 0x8000000,  // Key3
        'K2'      => 0x10000000, // Key2
        'ScoreV2' => 0x20000000, // ScoreV2
        'Lastmod' => 0x40000000  // LastMod
    ];

    // SD, PF, DT, NC 값 (위에 이름 바꿀 경우를 대비해서 hard-coding)
    $specialmod = [
        /* SD, PF, DT, NC */
        0x20, 0x4000, 0x40, 0x200
    ];

    // SD + PF = PF 통합하기
    if ($mode & $specialmod[0] && $mode & $specialmod[1]) $mode = $mode - $specialmod[0];
    // DT + NC = NC 통합하기
    if ($mode & $specialmod[2] && $mode & $specialmod[3]) $mode = $mode - $specialmod[2];

    foreach($mods as $name => $value) {
        if ($mode & $value) $ret .= $name . ', ';
    }

    // 마지막 2글자 빼기.
    if (strlen($ret) > 0)
        return substr($ret, 0, -2);
    else
        return NULL;
}

// 예제
echo mode_to_str(18046); // EZ, TD, HD, HR, NC, FL, PF
echo PHP_EOL;
echo gamemode_to_str(1); // Taiko
echo PHP_EOL;