IpToCidr函数

function ip2cidr($ip_start,$ip_end) {  if(long2ip(ip2long($ip_start))!=$ip_start or long2ip(ip2long($ip_end))!=$ip_end) return !trigger_error('ip 不合法', E_USER_NOTICE);   $ipl_start = ip2long($ip_start);  $ipl_end = ip2long($ip_end);  if($ipl_start>0 && $ipl_end<0) $delta = ($ipl_end + 4294967296) - $ipl_start;  else $delta = $ipl_end - $ipl_start;  $netmask = sprintf('%032b', $delta);  if(ip2long($ip_start)==0 && substr_count($netmask,"1")==32) return "0.0.0.0/0";  if($delta<0 or ($delta>0 && $delta%2==0)) return !trigger_error("区间数量不合法 $delta", E_USER_NOTICE);  for($mask=0; $mask<32; $mask++) if($netmask[$mask]==1) break;  if(substr_count($netmask,"0")!=$mask) {    $w = strrpos($netmask, '0') + 1;    $m = pow(2, 32-$w) - 1;    $ip_start = long2ip(($ipl_start & ~$m)+$m+1);    return long2ip($ipl_start & ~$m) . "/$w," . ip2cidr($ip_start,$ip_end);  };  return "$ip_start/$mask";} 

上面是版主大大给写的函数
ip2cidr("36.96.0.0","36.223.255.255")
执行结果36.96.0.0/9

反查
http://www.itmop.com/tool/ipaddress.php
36.96.0.0/9 -> 36.0.0.1 -36.127.255.254  与36.96.0.0 - 36.223.255.255 不一致

有个网站，但是无法看到转换代码
http://ip2cidr.com/
36.96.0.0-36.223.255.255
转化为36.96.0.0/11
36.128.0.0/10
36.192.0.0/11  

拆分区间不好掌握。。。

回复讨论(解决方案)

结果结果:可用地址:	  8388606掩码:	      255.128.0.0网络:	      36.96.0.0第一个可用:	36.0.0.1   最后可用：	 36.127.255.254  广播:	      36.223.255.255

怎么不对啦？

????有??啊。

36.96.0.0/9 -> 36.0.0.1 -36.127.255.254  
                     与36.96.0.0 - 36.223.255.255 不一致

1楼 2楼的 兄弟说完 我以为我手误  结果自己又测试了下  确实ip2cidr("36.96.0.0","36.223.255.255") 执行结果36.96.0.0/9
而36.96.0.0/9 生成IP的区间为 36. 0.0.1 -36. 127.255.254    

他那个计算和你的需求是不一样的
他算出的是，在给定的掩码条件下，一个 ip 可以隶属于哪个网段

需求不同，结果也不同

那可能我之前表述错误了 我的需求就是 用函数实现首IP地址和尾IP地址的区间转化为CIDR格式  这样就可以用来查询某个IP地址是否属于这个CIDR区域，其中检验的方法就是用CIDR再反生成首IP地址和尾IP地址的区间。
函数功能类似于http://ip2cidr.com 上的

其实这是 ip2cidr 的 bug
函数的原型来自 php 手册，只是增加了分段的功能
可以看到，分段是在原函数发现做为一段不行的时候进行的
但由于先天不足，他并没有把你的传入不能作为一段判别出来

不知道 这个网站http://ip2cidr.com/  它是怎么实现的  网上的资源好少

一篇国外的文章用JAVA实现了

import java.util.ArrayList;import java.util.List;import java.util.regex.Matcher;import java.util.regex.Pattern;public class RangeToCidr {    private static final String IP_ADDRESS = "(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})";    private static final Pattern addressPattern = Pattern.compile(IP_ADDRESS);    public static List<String> rangeToCidrList(String istart, String iend)  {               int start = toInteger(istart);        int end = toInteger(iend);        List<String> result = new ArrayList<String>();        while (end >= start) {            int maxsize = imaxblock( start, 32);            double x = (Math.log(end - start + 1) / Math.log(2) ) ;            int maxdiff = (int) (Math.floor(32 - Math.floor(x)));            String ip = intToIP(start);            if (maxsize < maxdiff) {                maxsize = maxdiff;            }            result.add( ip + "/" + (int)maxsize );            start += Math.pow(2, (32-maxsize));        }        return result;    }    private static int toInteger(String address) {        Matcher matcher = addressPattern.matcher(address);        if (matcher.matches()) {            return matchAddress(matcher);        }        else            throw new IllegalArgumentException("Could not parse [" + address + "]");    }    private static int matchAddress(Matcher matcher) {        int addr = 0;        for (int i = 1; i <= 4; ++i) {             int n = (rangeCheck(Integer.parseInt(matcher.group(i)), -1, 255));            addr |= ((n & 0xff) << 8*(4-i));        }        return addr;    }    private static int rangeCheck(int value, int begin, int end) {        if (value > begin && value <= end) // (begin,end]            return value;        throw new IllegalArgumentException("Value [" + value + "] not in range ("+begin+","+end+"]");    }    private static String intToIP(int val) {        int octets[] = new int[4];        for (int j = 3; j >= 0; --j)            octets[j] |= ((val >>> 8*(3-j)) & (0xff));        StringBuilder str = new StringBuilder();        for (int i =0; i < octets.length; ++i){            str.append(octets[i]);            if (i != octets.length - 1) {                str.append(".");             }        }        return str.toString();    }    private static long imask(int t)    {        return (long)(Math.pow(2, 32) - Math.pow(2, 32-t) ) ;    }    private static int imaxblock(long ibase, int tbit)  {        while (tbit > 0)    {            long im = imask(tbit-1);            long imand = ibase & im ;            if (imand != ibase) {                break;            }            tbit--;        }        return tbit;    }}

$r = ip2cidr("36.96.0.1","36.223.255.255");print_r($r);function ip2cidr($ip_start,$ip_end) {  $res = array();  if(long2ip(ip2long($ip_start))!=$ip_start or long2ip(ip2long($ip_end))!=$ip_end)    return !trigger_error('ip 不合法', E_USER_NOTICE);   $ipl_start = ip2long($ip_start);  if($ipl_start < 0) $ipl_start += 0x100000000;  $ipl_end = ip2long($ip_end);  if($ipl_end<0) $ipl_end += 0x100000000;  $ipl=$ipl_start;  do {    $k = strrpos(sprintf('%032b', $ipl), '1');    $cidr = $k + 1;    $dk = pow(2, 32-$k-1);    $mask = $dk - 1;    $res[] = sprintf("%s/%d", long2ip($ipl & ~$mask), $cidr);    $ipl += $dk;  }while($ipl < $ipl_end);  return $res;} 

Array(    [0] => 36.96.0.1/32    [1] => 36.96.0.2/31    [2] => 36.96.0.4/30    [3] => 36.96.0.8/29    [4] => 36.96.0.16/28    [5] => 36.96.0.32/27    [6] => 36.96.0.64/26    [7] => 36.96.0.128/25    [8] => 36.96.1.0/24    [9] => 36.96.2.0/23    [10] => 36.96.4.0/22    [11] => 36.96.8.0/21    [12] => 36.96.16.0/20    [13] => 36.96.32.0/19    [14] => 36.96.64.0/18    [15] => 36.96.128.0/17    [16] => 36.97.0.0/16    [17] => 36.98.0.0/15    [18] => 36.100.0.0/14    [19] => 36.104.0.0/13    [20] => 36.112.0.0/12    [21] => 36.128.0.0/9)

还有个更简单的 其中2个函数PHP都有库函数  实测也可以

import java.util.ArrayList;import java.util.List;public class RangeToCidr {    public static List<String> range2cidrlist( String startIp, String endIp ) {                 long start = ipToLong(startIp);                 long end = ipToLong(endIp);                   ArrayList<String> pairs = new ArrayList<String>();                 while ( end >= start ) {                         byte maxsize = 32;                         while ( maxsize > 0) {                                 long mask = CIDR2MASK[ maxsize -1 ];                                 long maskedBase = start & mask;                                 if ( maskedBase != start ) {                                         break;                                 }                                 maxsize--;                         }                           double x = Math.log( end - start + 1) / Math.log( 2 );                         byte maxdiff = (byte)( 32 - Math.floor( x ) );                         if ( maxsize < maxdiff) {                                 maxsize = maxdiff;                         }                         String ip = longToIP(start);                         pairs.add( ip + "/" + maxsize);                         start += Math.pow( 2, (32 - maxsize) );                 }                 return pairs;         }           public static final int[] CIDR2MASK = new int[] { 0x00000000, 0x80000000,                     0xC0000000, 0xE0000000, 0xF0000000, 0xF8000000, 0xFC000000,                     0xFE000000, 0xFF000000, 0xFF800000, 0xFFC00000, 0xFFE00000,                     0xFFF00000, 0xFFF80000, 0xFFFC0000, 0xFFFE0000, 0xFFFF0000,                     0xFFFF8000, 0xFFFFC000, 0xFFFFE000, 0xFFFFF000, 0xFFFFF800,                     0xFFFFFC00, 0xFFFFFE00, 0xFFFFFF00, 0xFFFFFF80, 0xFFFFFFC0,                     0xFFFFFFE0, 0xFFFFFFF0, 0xFFFFFFF8, 0xFFFFFFFC, 0xFFFFFFFE,                     0xFFFFFFFF };           private static long ipToLong(String strIP) {                 long[] ip = new long[4];                 String[] ipSec = strIP.split("\\.");                 for (int k = 0; k < 4; k++) {                         ip[k] = Long.valueOf(ipSec[k]);                 }                 return (ip[0] << 24) + (ip[1] << 16) + (ip[2] << 8) + ip[3];         }           private static String longToIP(long longIP) {                 StringBuffer sb = new StringBuffer("");                 sb.append(String.valueOf(longIP >>> 24));                 sb.append(".");                 sb.append(String.valueOf((longIP & 0x00FFFFFF) >>> 16));                 sb.append(".");                 sb.append(String.valueOf((longIP & 0x0000FFFF) >>> 8));                 sb.append(".");                 sb.append(String.valueOf(longIP & 0x000000FF));           return sb.toString();         } }

版主大大 看12楼的 JAVA 函数思路 是否可以优化您的代码 以生成3个CIDR 36.96.0.0/11  36.128.0.0/10 36.192.0.0/11  
最终让这个函数在PHP沉淀下来 为大家造福

$r = ip2cidr("36.96.0.0","36.223.255.255");print_r($r);

Array(    [0] => 36.96.0.0/11    [1] => 36.128.0.0/9)

你给的那个链接，最后一节的结果是错的

您说的是http://ip2cidr.com/   还是12楼的函数？

确实 36.128.0.0/9  已经超出了36.223.255.255

$r = ip2cidr("36.96.0.0","36.223.255.255");print_r($r);function ip2cidr($ip_start,$ip_end) {  $res = array();  if(long2ip(ip2long($ip_start))!=$ip_start or long2ip(ip2long($ip_end))!=$ip_end)    return !trigger_error('ip 不合法', E_USER_NOTICE);   $ipl_start = ip2long($ip_start);  if($ipl_start < 0) $ipl_start += 0x100000000;  $ipl_end = ip2long($ip_end);  if($ipl_end<0) $ipl_end += 0x100000000;  $ipl=$ipl_start;  do {    $k = strrpos(sprintf('%032b', $ipl), '1');    $cidr = $k + 1;    $dk = pow(2, 32-$k-1);    if($ipl + $dk > $ipl_end) { $dk /= 2; $cidr++; }    $mask = $dk - 1;    $res[] = sprintf("%s/%d", long2ip($ipl & ~$mask), $cidr);    $ipl += $dk;  }while($ipl < $ipl_end);  return $res;} 

Array(    [0] => 36.96.0.0/11    [1] => 36.128.0.0/10    [2] => 36.192.0.0/11)

我试试不同的IP地址段 做个测试

拆的好开呀。。。 版主大大 看看 还能优化下吗

$ip_st = "103.233.183.0";$ip_end = "103.233.183.255";print $ip_st."-".$ip_end."<br>";$cidr_arr =  ip2cidr($ip_st,$ip_end );print_r($cidr_arr);print "<br>";for($i = 0 ; $i < count($cidr_arr); $i++){	print $cidr_arr[$i]." : ";	print cidr_conv($cidr_arr[$i])."<br>";	}

103.233.183.0-103.233.183.255
Array ( [0] => 103.233.183.0/25 [1] => 103.233.183.128/26 [2] => 103.233.183.192/27 [3] => 103.233.183.224/28 [4] => 103.233.183.240/29 [5] => 103.233.183.248/30 [6] => 103.233.183.252/31 [7] => 103.233.183.254/32 ) 
103.233.183.0/25 : 103.233.183.0 - 103.233.183.127
103.233.183.128/26 : 103.233.183.128 - 103.233.183.191
103.233.183.192/27 : 103.233.183.192 - 103.233.183.223
103.233.183.224/28 : 103.233.183.224 - 103.233.183.239
103.233.183.240/29 : 103.233.183.240 - 103.233.183.247
103.233.183.248/30 : 103.233.183.248 - 103.233.183.251
103.233.183.252/31 : 103.233.183.252 - 103.233.183.253
103.233.183.254/32 : 103.233.183.254 - 103.233.183.254

function cidr_conv($cidr_address) {  $first = substr($cidr_address, 0, strpos($cidr_address, "/"));  $netmask = substr(strstr($cidr_address, "/"), 1);  $first_bin = str_pad(decbin(ip2long($first)), 32, "0", STR_PAD_LEFT);  $netmask_bin = str_pad(str_repeat("1", (integer)$netmask), 32, "0", STR_PAD_RIGHT);    for ($i = 0; $i < 32; $i++) {    if ($netmask_bin[$i] == "1")       $last_bin .= $first_bin[$i];    else      $last_bin .= "1";  }  $last = long2ip(bindec($last_bin));  return "$first - $last";}

$r = ip2cidr("103.233.183.0", "103.233.183.255");print_r($r);function ip2cidr($ip_start,$ip_end) {  $res = array();  if(long2ip(ip2long($ip_start))!=$ip_start or long2ip(ip2long($ip_end))!=$ip_end)    return !trigger_error('ip 不合法', E_USER_NOTICE);   $ipl_start = ip2long($ip_start);  if($ipl_start < 0) $ipl_start += 0x100000000;  $ipl_end = ip2long($ip_end);  if($ipl_end<0) $ipl_end += 0x100000000;  $ipl=$ipl_start;  do {    $k = strrpos(sprintf('%032b', $ipl), '1');    $cidr = $k + 1;    $dk = pow(2, 32-$k-1);    if($ipl + $dk > $ipl_end + 1) { $dk /= 2; $cidr++; }    $mask = $dk - 1;    $res[] = array(      'cidr' => sprintf("%s/%d", long2ip($ipl & ~$mask), $cidr),      'mask' => long2ip(~$mask),      'net' => long2ip($ipl & ~$mask),      'usable' => $mask - 1,      'start' => long2ip(($ipl & ~$mask) + 1),      'end' => long2ip(($ipl | $mask) - 1),      'broadcast' => long2ip($ipl | $mask),    );    $ipl += $dk;  }while($ipl < $ipl_end);  return $res;}

Array(    [0] => Array        (            [cidr] => 103.233.183.0/24            [mask] => 255.255.255.0            [net] => 103.233.183.0            [usable] => 254            [start] => 103.233.183.1            [end] => 103.233.183.254            [broadcast] => 103.233.183.255        ))

$r = ip2cidr("210.80.0.0", "210.80.63.255");
print_r($r);

Array
( 
      [0] => Array 
      (
              [cidr] => 210.80.0.0/13
              [mask] => 255.248.0.0
              [net] => 210.80.0.0 
              [usable] => 524286
              [start] => 210.80.0.1 
              [end] => 210.87.255.254
              [broadcast] => 210.87.255.255 
       )
 ) 
这块就存在BUG了  您看下12楼的方法是否合适

最终函数：

$CIDR2MASK = array( 0x00000000, 0x80000000,                     0xC0000000, 0xE0000000, 0xF0000000, 0xF8000000, 0xFC000000,                     0xFE000000, 0xFF000000, 0xFF800000, 0xFFC00000, 0xFFE00000,                     0xFFF00000, 0xFFF80000, 0xFFFC0000, 0xFFFE0000, 0xFFFF0000,                     0xFFFF8000, 0xFFFFC000, 0xFFFFE000, 0xFFFFF000, 0xFFFFF800,                     0xFFFFFC00, 0xFFFFFE00, 0xFFFFFF00, 0xFFFFFF80, 0xFFFFFFC0,                     0xFFFFFFE0, 0xFFFFFFF0, 0xFFFFFFF8, 0xFFFFFFFC, 0xFFFFFFFE,                     0xFFFFFFFF );        function ipTocidr($ip_start,$ip_end) { 	global $CIDR2MASK;       $StartIp = ip2long($ip_start);        $EndIp = ip2long($ip_end);   $pairs = array();             while ( $EndIp >= $StartIp )   {                   $maxsize = 32;               while ( $maxsize > 0)       {                      $mask = $CIDR2MASK[$maxsize-1];                        $maskedBase = $StartIp & $mask ;                           if ( $maskedBase != $StartIp )           {                                  break;                           }                           $maxsize--;                   }                 $x = log( $EndIp -  $StartIp + 1) / log(2);                   $maxdiff = 32 - floor($x) ;                   if ( $maxsize < $maxdiff)       {                           $maxsize = $maxdiff;                   }                   $ip = long2ip($StartIp);       $pairs[] = $ip."/".$maxsize;                                      $StartIp += pow( 2, (32 - $maxsize) );         }           return $pairs;     }   

谢谢版主大大的悉心指导，最后还是将JAVA的函数翻译了