主页 / coding / 问题 / 77600454
Accepted
inf3rno
Asked: 2023-12-04 23:01:26 +0800 CST

迭代字节字符串的 n 位块

  • 772

我有这样的代码：

$alphabet = array('0','1','2','3','4','5','6','7','8','9','a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z');
$alphabetSize = count($alphabet);
$alphabetBitSize = ceil(log($alphabetSize, 2));
$bitSize = $length * $alphabetBitSize;
$bytes = random_bytes(ceil($bitSize/8));

我需要的是读取$bitSize循环中的位以使用字母表生成 latin1 字符串。现在我完全不知道如何用$bytes我所拥有的来做到这一点。大多数答案都是使用字符串函数来做到这一点，但我想我需要一些二进制的东西。另一种选择可能是用十六进制来做。有什么提示吗？

3 个回答

  1. Best Answer

    我一般会使用PHP的内置函数unpack()将字节转换为十六进制字符串，然后再转换为二进制字符串。我希望这有帮助。

    $alphabet = array('0','1','2','3','4','5','6','7','8','9','a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z');
$alphabetSize = count($alphabet);
$alphabetBitSize = ceil(log($alphabetSize, 2));
$bitSize = $length * $alphabetBitSize;
$bytes = random_bytes(ceil($bitSize/8));

$binaryStr = '';
foreach (unpack('C*', $bytes) as $byte) {
    $binaryStr .= sprintf("%08b", $byte);
}

$resultString = '';
for ($i = 0; $i < strlen($binaryStr); $i += $alphabetBitSize) {
    $bitSegment = substr($binaryStr, $i, $alphabetBitSize);
    $index = bindec($bitSegment) % $alphabetSize;
    $resultString .= $alphabet[$index];
}

echo $resultString;
    • 1

  2. 要从循环中的随机字节生成字符串，可以使用按位运算从字节序列中提取必要的位。您可以尝试以下代码：

    $alphabet = array('0','1','2','3','4','5','6','7','8','9','a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z');
    $alphabetSize = count($alphabet);
    $alphabetBitSize = ceil(log($alphabetSize, 2));
    
    $length = 10;  // Set your desired length
    $bitSize = $length * $alphabetBitSize;
    $bytes = random_bytes(ceil($bitSize/8));
    
    $result = '';
    $byteIndex = 0;
    $bitIndex = 0;
    
    for ($i = 0; $i < $bitSize; $i++) {
        $byte = ord($bytes[$byteIndex]);
        $bit = ($byte >> (7 - $bitIndex)) & 1;
        $result .= $alphabet[$bit];
        
        $bitIndex++;
        if ($bitIndex == 8) {
            $bitIndex = 0;
            $byteIndex++;
        }
    }
    
    echo $result;

    在此示例中，我使用 ord 函数从随机字节中获取字符的 ASCII 值。然后，执行按位移位和掩码以提取每一位。结果位用于索引字母表数组以形成最终字符串。

    让我知道这是否适合你..

    • 1

  3. 我用 bin2hex 编写了自己的代码

    function generateHexString($length){
    $bitSize = $length*4;
    $bytes = random_bytes(ceil($bitSize/8));
    $hex = bin2hex($bytes);
    return substr($hex, 0, $length);
}

function generateLatinString($length){
    $alphabet = array(
        '0','1','2','3','4','5','6','7','8','9',
        'a','b','c','d','e','f','g','h','i','j',
        'k','l','m','n','o','p','q','r','s','t',
        'u','v','w','x','y','z'
    );
    $alphabetSize = count($alphabet);
    $hexChunkSize = (int)(ceil(log($alphabetSize, 16)));
    $hexString = generateHexString($length*$hexChunkSize);
    $string = '';
    $hexChars = str_split($hexString);
    $characterIndex = 0;
    $chunkIndex = 0;
    foreach ($hexChars as $hexChar){
        $characterIndex += hexdec($hexChar) * pow(16, $chunkIndex);
        ++$chunkIndex;
        if ($chunkIndex === $hexChunkSize){
            while ($characterIndex >= $alphabetSize)
                $characterIndex -= $alphabetSize;
            $character = $alphabet[$characterIndex];
            $string .= $character;
            $chunkIndex = 0;
        }
    }
    return $string;
}
    • 1

相关问题