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    long2ip

    (PHP 4, PHP 5, PHP 7, PHP 8)

    long2ip — 将长整型转化为字符串形式带点的互联网标准格式地址（IPV4）

    说明

    long2ip(int $ip): string|false

    long2ip() 函数通过长整型的表达形式转化生成带点格式的互联网地址（例如：aaa.bbb.ccc.ddd ）。

    参数

    ip

    合格的地址，长整型的表达形式。

    返回值

    返回字符串的互联网 IP 地址， 或者在失败时返回 false。

    更新日志

    版本 说明
    7.1.0 参数 ip 的类型从 string 改成 int。

    注释

    注意:

    在 32 位架构中，从 string 转换 int 整型形式的 ip 地址将有可能导致错误的结果，因为结果数字超出了 PHP_INT_MAX 限制。

    参见

    • ip2long() - 将 IPV4 的字符串互联网协议转换成长整型数字

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    User Contributed Notes 7 notes

    up
    3
    steve at computurn dot com
    6 years ago
    For a 32bit safe long2ip, which can accept string or signed integer input, try:

      function safelong2ip($long) {
        $binStr = sprintf("%032s", decbin((float)$long));
        if (strlen($binStr) != 32) {
          throw new Exception("Invalid IPv4 subnet!");
        }

        $ipArr = [];
        for ($i = 0; $i < 4; ++$i) {
          $ipArr[] = bindec(substr($binStr, $i*8, 8));
        }

        return implode('.', $ipArr);
      }
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    8
    Gabriel Malca
    18 years ago
    If the function doesn't exist:

    <?
            if (!function_exists("long2ip")) {
            function     long2ip($long) {
                    // Valid range: 0.0.0.0 -> 255.255.255.255
                    if ($long < 0 || $long > 4294967295) return false;
                    $ip = "";
                for (    $i=3;$i>=0;$i--) {
                        $ip .= (int)($long / pow(256,$i));
                        $long -= (int)($long / pow(256,$i))*pow(256,$i);
                    if (    $i>0) $ip .= ".";
                }
                return     $ip;
            }
        }
    ?>
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    1
    Rolf
    3 years ago
    an Anonymous wrote several years ago that you should cast the parameter to float to make sure that you get the right result on 32-bit machines. That probably never worked.

    But the idea is on a good track: to convert a bitstring into an ip, use

    $ip = long2ip((int)bindec($bits));

    This works on 32- and 64-bit machines.
    up
    1
    Tom Crosley
    21 years ago
    I wanted to be able to pass an IP address in a URL always as an unsigned int.  I then converted it back as shown below:

    $ip_addr = "192.168.100.25";  // example IP address that converts to neg #

    $s32int = ip2long($ip_addr);

    $us32str = sprintf("%u",$s32int);               // convert to unsigned string

    // display orig IP address, signed 32 bit version, unsigned 32 bit ver,
    // finally converted back to IP addr

    printf("%s ,%d, %s, %s", $ip_addr, $s32int, $us32str,
             long2ip(-(4294967296-$us32str)));

    // tested on Linux/Apache PHP 4.1.2
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    0
    klawd at kamundo dot de
    12 years ago
    Use these two functions to convert from and to numbers compatible to MySQLs INET_ATON and INET_NTOA
    <?php
            function convertIpToString($ip)
        {
                $long = 4294967295 - ($ip - 1);
            return     long2ip(-$long);
        }
        function     convertIpToLong($ip)
        {
            return     sprintf("%u", ip2long($ip));
        }
    ?>
    up
    -2
    Anonymous
    13 years ago
    If you're running a 32 bit machine you can get wrong IPs. To prevent from this just cast to float e.g.

    <?php
    long2Ip32bit    ($ip){
       return     long2ip((float)$ip);
    }
    ?>
    up
    -11
    php dot net at davidstockton dot com
    16 years ago
    Beware when processing values that are invalid, you may get values that are different based on the OS.  For instance:

    $ip = long2ip(pow(2,32)+1024);

    On windows you get 255.255.255.255.  On linux it's 0.0.4.0.

    So it seems it would be important to make sure the long you're converting is in the correct range.
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