php 还原cocos加密后的uuid

<?php

// 22位压缩后的 UUID解码配置
$BASE64_KEYS = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';
$values = array_fill(0, 123, 64); // max char code in base64Keys
for ($i = 0; $i < 64; ++$i) {
    $charCode = ord($BASE64_KEYS[$i]);
    $values[$charCode] = $i;
}

// 23位压缩后的 UUID解码配置
$Base64KeyChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
$AsciiTo64 = array_fill(0, 128, 0);
for ($i = 0; $i < 64; ++$i) {
    $charCode = ord($Base64KeyChars[$i]);
    $AsciiTo64[$charCode] = $i;
}

// 其他配置
$BASE64_VALUES = $values;
$HexChars = str_split('0123456789abcdef');
$_t = array('', '', '', '');
// 修正 $UuidTemplate 的初始化
$UuidTemplate = array_merge($_t, $_t, array('-'), $_t, array('-'), $_t, array('-'), $_t, array('-'), $_t, $_t, $_t);
// 生成 $Indices
$Indices = array();
foreach ($UuidTemplate as $key => $value) {
    if ($value !== '-') {
        $Indices[] = $key;
    }
}

/**
 * 22位压缩后的 UUID解码
 * @param string $base64 压缩后的 UUID 字符串
 * @return string 解码后的标准 UUID 字符串
 */
function decodeUuid($base64) {
    global $BASE64_VALUES, $Indices, $HexChars;
    
    $strs = explode('@', $base64);
    $uuid = $strs[0];
    if (strlen($uuid) !== 22) {
        return decompressUuid($uuid);
    }
    
    $result = array_fill(0, 36, '-');
    $result[0] = $base64[0];
    $result[1] = $base64[1];
    $index = 2;
    
    for ($i = 2; $i < 22; $i += 2) {
        $lhs = $BASE64_VALUES[ord($base64[$i])];
        $rhs = $BASE64_VALUES[ord($base64[$i + 1])];
        
        $result[$Indices[$index++]] = $HexChars[($lhs >> 2) & 0xF];
        $result[$Indices[$index++]] = $HexChars[(((3 & $lhs) << 2) | ($rhs >> 4)) & 0xF];
        $result[$Indices[$index++]] = $HexChars[$rhs & 0xF];
    }
    
    return implode('', $result);
}

/**
 * 23位压缩后的 UUID解码
 * @param string $uuid 压缩后的 UUID 字符串
 * @return string 解码后的标准 UUID 字符串
 */
function decompressUuid($uuid) {
    global $AsciiTo64, $HexChars;
    
    // 检查输入的 uuid 长度是否符合要求
    if (strlen($uuid) < 23) {
        error_log('Invalid UUID length. Expected at least 23 characters.');
        return '';
    }
    
    // 存储解码后的十六进制字符
    $decodedHexChars = array();
    
    // 从第 5 个字符开始，每 2 个字符一组进行解码
    for ($index = 5; $index < 23; $index += 2) {
        $firstCharValue = $AsciiTo64[ord($uuid[$index])];
        $secondCharValue = $AsciiTo64[ord($uuid[$index + 1])];
        
        // 解码逻辑
        $decodedHexChars[] = dechex($firstCharValue >> 2);
        $decodedHexChars[] = dechex(((3 & $firstCharValue) << 2) | ($secondCharValue >> 4));
        $decodedHexChars[] = dechex(15 & $secondCharValue);
    }
    
    // 拼接解码后的 uuid
    $decodedUuid = substr($uuid, 0, 5) . implode('', $decodedHexChars);
    
    // 格式化 uuid 为标准格式
    return implode('-', array(
        substr($decodedUuid, 0, 8),
        substr($decodedUuid, 8, 4),
        substr($decodedUuid, 12, 4),
        substr($decodedUuid, 16, 4),
        substr($decodedUuid, 20)
    ));
}

// 测试
$compressedUuid22 = 'example22char@';
$compressedUuid23 = 'example23char';

echo decodeUuid($compressedUuid22) . "\n";
echo decompressUuid($compressedUuid23) . "\n";

?>