以十六进制编码/解码字符串并返回

Question

给定一个可能包含任意字符（包括unicode字符）的字符串，如何将这个字符串转换为十六进制表示，然后反转得到这个字符串的十六进制？

Answer 1

使用

pack()

和

unpack()

:

function hex2str($hex) {
  return pack('H*', $hex);
}

function str2hex($str) {
  $unpacked = unpack('H*', $str);
  return array_shift($unpacked);
}

$txt = 'This is test';
$hex = str2hex($txt);
$str = hex2str($hex);

echo "{$txt} => {$hex} => {$str}\n";

会产生

这是测试 => 546869732069732074657374 => 这是测试

Answer 2

使用这样的函数：

<?php
function bin2hex($str) {
    $hex = "";
    $i = 0;
    do {
        $hex .= dechex(ord($str{$i}));
        $i++;
    } while ($i < strlen($str));
    return $hex;
}

// Look what happens when ord($str{$i}) is 0...15
// you get a single digit hexadecimal value 0...F

// bin2hex($str) could return something like 4a3,
// decimals(74, 3), whatever the binary value is of those.

function hex2bin($str) {
    $bin = "";
    $i = 0;
    do {
        $bin .= chr(hexdec($str{$i}.$str{($i + 1)}));
        $i += 2;
    } while ($i < strlen($str));
    return $bin;
}

// hex2bin("4a3") just broke. Now what?

// Using sprintf() to get it right.
function bin2hex($str) {
    $hex = "";
    $i = 0;
    do {
        $hex .= sprintf("%02x", ord($str{$i}));
        $i++;
    } while ($i < strlen($str));
    return $hex;
}

// now using whatever the binary value of decimals(74, 3)
// and this bin2hex() you get a hexadecimal value you can
// then run the hex2bin function on. 4a03 instead of 4a3.
?>

来源：http://php.net/manual/en/function.bin2hex.php