How to convert ip to integer in php

php method to convert ip to integer: 1. Create a PHP sample file; 2. Convert the ip address to an integer through the "ip2long($ip);" method.

The operating environment of this article: Windows 7 system, PHP version 7.1, DELL G3 computer

How to convert ip to integer in php?

Detailed explanation of the mutual conversion of IP addresses and integer numbers in PHP

This article mainly introduces the detailed explanation of the mutual conversion of IP addresses and integer numbers in PHP. This article introduces the use of PHP functions ip2long and long2ip, as well as their BUG introduction, and finally gives two algorithms written by myself. Friends who need it can refer to it

Converting IP into integer storage is a database optimization method The general trend is that many people are still using string type storage when storing IP. String index consumes more resources than integer index, especially when the amount of data in the table is large, and when you want to query the data of a certain IP segment, today The ip mentioned refers to ip4, ip6 is not within the scope of this article.

System functions ip2long and long2ip
There is a built-in function ip2long in PHP that can convert the ip address to an integer.

The code is as follows:

$ip = '210.110.11.49';echo ip2long($ip);

Output:

-764540111

The output integer type has a negative sign because the result we get is a signed integer type, and the maximum value of the signed integer type is 2147483647. To convert the result to unsigned type, you can write like this

3530427185

Use long2ip to convert the integer type back to the IP address

$ip = '210.110.11.49';$ip_int = ip2long($ip);echo $ip."<br />";echo $ip_int."<br />";echo long2ip($ip_int);

Output:

210.110.011.49
-764540623
210.110.9.49

The conversion results do not match, we try to add a leading 0 before the first number of the ip, and then look at the

$ip = '021.110.11.49';$ip_int = ip2long($ip);echo $ip."<br />";echo $ip_int."<br />";echo long2ip($ip_int);

output:

021.110.11.49
292424497
17.110.11.49

The conversion results are all wrong. The above examples are all caused by adding leading 0, resulting in an error in the conversion result, and the reversal result does not match the original converted IP.

Conversion Principle

There are currently two algorithms:
First, the first section is multiplied by the cube of 256, and the second section is multiplied by The square of 256, the third segment is multiplied by 256, and the final sum is

$ip = '0210.110.11.49'; 
function ipToInt($ip){    $iparr = explode('.',$ip);    $num = 0;    for($i=0;$i<count($iparr);$i++){        $num += intval($iparr[$i]) * pow(256,count($iparr)-($i+1));
    }    return $num;
} 
echo  $ip.'<br />';$ip_int = ipToInt($ip);echo $ip_int.'<br />';echo long2ip($ip_int);

Output:

0210.110.11.49
3530427185
210.110.11.49

Second, through the bitwise operator

$ip = '0210.110.11.49'; 
function ipToInt($ip){    $iparr = explode('.',$ip);    return (intval($iparr[0]<<24))|(intval($iparr[1])<<16)|(intval($iparr[2])<<8)| (intval($iparr[3]));
} 
echo  $ip.'<br />';$ip_int = ipToInt($ip);echo $ip_int.'<br />';echo long2ip($ip_int);

Output:

0210.110.11.49
-764540111
210.110.11.49

Check whether the IP is legal

First, traverse the test yourself

function check_ip($ip){    $iparr = explode('.',$ip);    foreach($iparr as $v){ if($v>255) return false; }    return true;
} 
echo '210.285.11.49,';var_dump(check_ip('210.285.11.49'));echo '<br />';echo '210.205.11.49,';var_dump(check_ip('210.205.11.49'));
[code]

输出：
[code]210.285.11.49,bool(false)210.205.11.49,bool(true)

No. 2. Use ip2long to return

function check_ip($ip){    if(ip2long($ip)) return true;    return false;
} 
echo '210.285.11.49,';var_dump(check_ip('210.285.11.49'));echo '<br />';echo '210.205.11.49,';var_dump(check_ip('210.205.11.49'));

Output:

210.285.11.49,bool(false)210.205.11.49,bool(true)

Postscript

Many people use ip2long to convert the ip writing library to store int type In the field, however, on different system platforms, the values ​​obtained by the ip2long function are different, so it may cause that the ip obtained by using long2ip when reversing the ip is read from the database and does not match the original ip
If it is Mysql can be solved using the mysql system functions INET_ATON and INET_NTOA, or using the bigint type, or writing functions yourself.

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