php 将十六进制转换为 ascii 字符
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Convert hex to ascii characters
提问by Dziamid
Is it possible to represent a sequence of hex characters (0-9A-F) with a sequence of 0-9a-zA-Z characters, so the the result sequence is smaller and can be decoded?
是否可以用0-9a-zA-Z字符序列表示一个十六进制字符序列（0-9A-F），所以结果序列更小，可以解码？
For example:
例如：
$hex = '5d41402abc4b2a76b9719d911017c592';
echo $string = encode($hex); // someASCIIletters123
echo decode(string) == $hex; //true
采纳答案by Jon
回答by Andrew
I think you're looking for this:
我想你正在寻找这个：
function hex2str($hex) {
$str = '';
for($i=0;$i<strlen($hex);$i+=2) $str .= chr(hexdec(substr($hex,$i,2)));
return $str;
}
(From http://www.linux-support.com/cms/php-convert-hex-strings-to-ascii-strings/) (Works like this javascript tool: http://www.dolcevie.com/js/converter.html)
（来自http://www.linux-support.com/cms/php-convert-hex-strings-to-ascii-strings/）（像这个 javascript 工具一样工作：http: //www.dolcevie.com/js/转换器.html)
回答by Marc B
You mean want to convert a string of hex digits into actual hex values?
您的意思是要将一串十六进制数字转换为实际的十六进制值吗？
$hex_string = "A1B2C3D4F5"; // 10 chars/bytes
$packed_string = pack('H*', $hex_string); // 0xA1B2C3D4F5 // 5 chars/bytes.
回答by Jon Skeet
Well, something similar, yes... parse the hex characters as a binary value, then convert to base64. That uses a littlebit more than 0-9 a-z A-Z, but only a few more characters. Are you okay to use three other characters in addition to those 62? You can use base64_encodeto perform the encoding if so.
嗯，类似的东西，是的...将十六进制字符解析为二进制值，然后转换为 base64。这比 0-9 az AZ使用的多一点，但只使用了几个字符。除了那 62 个字符之外，您还可以使用其他三个字符吗？base64_encode如果是这样，您可以使用来执行编码。
(You could convert to base32 instead, but that wouldn't be as compact. Converting to bases which aren't powers of 2 is also feasible, but less appealing.)
（您可以改为转换为 base32，但这不会那么紧凑。转换为不是 2 的幂的基数也是可行的，但不太吸引人。）
You'd also need some way of representing a final half-byte if your input sequence had an odd number of characters. You'll probably want to think about that before calling packto do the original parsing...
如果您的输入序列有奇数个字符，您还需要某种方式来表示最后的半字节。在调用pack进行原始解析之前，您可能需要考虑一下...
