(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）
$ip): string|falselong2ip() 函数通过长整型的表达形式转化生成带点格式的互联网地址（例如：aaa.bbb.ccc.ddd ）。
ip合格的地址，长整型的表达形式。
返回字符串的互联网 IP 地址， 或者在失败时返回 false。
| 版本 | 说明 |
|---|---|
| 7.1.0 |
参数 ip 的类型从 string 改成 int。
|
注意:
在 32 位架构中，从 string 转换 int 整型形式的 ip 地址将有可能导致错误的结果，因为结果数字超出了
PHP_INT_MAX限制。
For a 32bit safe long2ip, which can accept string or signed integer input, try:
function safelong2ip($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('.', $ipArr);
}If the function doesn't exist:
<?
if (!function_exists("long2ip")) {
function long2ip($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;
}
}
?>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.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 4.1.2Use 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($ip));
}
?>If you're running a 32 bit machine you can get wrong IPs. To prevent from this just cast to float e.g.
<?php
long2Ip32bit($ip){
return long2ip((float)$ip);
}
?>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.