java - 将按位运算Java代码转换为PHP

Question

您好，有一种用 Java 编写的计算校验和的方法。这是代码:

01  public String getChecksum() {
02      String checkSumBuffer = getMessageHeader() + getConversationHeader() + getTransactionHeader() + operationInformation;
03      char[] res = new char[4];
04      for (int j = 0; j < res.length; j++) {
05          for (int i = j; i < checkSumBuffer.length(); i = i + 4) {
06              res[j] = (char) (res[j] ^ checkSumBuffer.charAt(i));
07          }
08          res[j] = (char) ((~res[j]) & 0x00ff);
09      }
10      String strCheckSum = "";
11      for (int i = 0; i < 4; i++) {
12          strCheckSum = strCheckSum + Integer.toHexString((int) res[i]);
13      }
14      checksum = strCheckSum.toUpperCase();
15      return checksum;
16  }

这是 PHP 等效代码:

00  public function getChecksum() {
01      $checkSumBuffer = $this->getMessageHeader() . $this->getConversationHeader() . $this->getTransactionHeader() . $this->operationInformation;
02      $res = array(0,0,0,0); // array with 4 elements
03      for ($j = 0; $j < count($res); $j++) {
04          for ($i = $j; $i < strlen($checkSumBuffer); $i = $i + 4) {
05              $res[$j] = $res[$j] ^ $checkSumBuffer[$i];
06          }
07          $res[$j] = ((~$res[$j]) & 0x00ff);
08      }
09      $strCheckSum = "";
10      for ($i = 0; $i < 4; $i++) {
11          $strCheckSum = $strCheckSum . dechex($res[$i]);
12      }
13      $this->checksum = strtoupper($strCheckSum);*/
14      return $this->checksum;
15  }

但是PHP代码有问题。这是每种方法的输出:Java 输出:C0E8F098php 输出:FEFEFFFF

我认为问题在于java代码中的res变量是char类型，而在php代码中是int类型。如果那是问题所在，我该如何实现？我以为我可以使用 chr接受一个 ASCII 代码并返回字符的函数。但它不起作用，输出为:0000

我应该查看这些代码中的哪些差异来解决它？

Answer 1

让我们让 php 也使用 char:

$res = array("\0", "\0", "\0", "\0"); // instead of $res = array(0,0,0,0);

$res[$j] = ((~$res[$j]) & "\xff"); // instead of $res[$j] = ((~$res[$j]) & 0x00ff);

$strCheckSum = $strCheckSum . bin2hex($res[$i]); // instead of $strCheckSum = $strCheckSum . dechex($res[$i]);