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<?php
/**
* ip2region php seacher client class
*
* @author chenxin<chenxin619315@gmail.com>
* @date 2015-10-29
*/
defined('INDEX_BLOCK_LENGTH') or define('INDEX_BLOCK_LENGTH', 12);
defined('TOTAL_HEADER_LENGTH') or define('TOTAL_HEADER_LENGTH', 8192);
class Ip2Region
{
/**
* db file handler
*/
private $dbFileHandler = NULL;
/**
* header block info
*/
private $HeaderSip = NULL;
private $HeaderPtr = NULL;
private $headerLen = 0;
/**
* super block index info
*/
private $firstIndexPtr = 0;
private $lastIndexPtr = 0;
private $totalBlocks = 0;
/**
* for memory mode only
* the original db binary string
*/
private $dbBinStr = NULL;
private $dbFile = NULL;
/**
* construct method
*
* @param ip2regionFile
*/
public function __construct( $ip2regionFile)
{
$this->dbFile = $ip2regionFile;
}
/**
* all the db binary string will be loaded into memory
* then search the memory only and this will a lot faster than disk base search
* @Note:
* invoke it once before put it to public invoke could make it thread safe
*
* @param $ip
*/
public function memorySearch($ip)
{
//check and load the binary string for the first time
if ( $this->dbBinStr == NULL ) {
$this->dbBinStr = file_get_contents($this->dbFile);
if ( $this->dbBinStr == false ) {
throw new Exception("Fail to open the db file {$this->dbFile}");
}
$this->firstIndexPtr = self::getLong($this->dbBinStr, 0);
$this->lastIndexPtr = self::getLong($this->dbBinStr, 4);
$this->totalBlocks = ($this->lastIndexPtr-$this->firstIndexPtr)/INDEX_BLOCK_LENGTH + 1;
}
if ( is_string($ip) ) $ip = self::safeIp2long($ip);
//binary search to define the data
$l = 0;
$h = $this->totalBlocks;
$dataPtr = 0;
while ( $l <= $h ) {
$m = (($l + $h) >> 1);
$p = $this->firstIndexPtr + $m * INDEX_BLOCK_LENGTH;
$sip = self::getLong($this->dbBinStr, $p);
if ( $ip < $sip ) {
$h = $m - 1;
} else {
$eip = self::getLong($this->dbBinStr, $p + 4);
if ( $ip > $eip ) {
$l = $m + 1;
} else {
$dataPtr = self::getLong($this->dbBinStr, $p + 8);
break;
}
}
}
//not matched just stop it here
if ( $dataPtr == 0 ) return NULL;
//get the data
$dataLen = (($dataPtr >> 24) & 0xFF);
$dataPtr = ($dataPtr & 0x00FFFFFF);
return array(
'city_id' => self::getLong($this->dbBinStr, $dataPtr),
'region' => substr($this->dbBinStr, $dataPtr + 4, $dataLen - 4)
);
}
/**
* get the data block through the specified ip address or long ip numeric with binary search algorithm
*
* @param ip
* @return mixed Array or NULL for any error
*/
public function binarySearch( $ip )
{
//check and conver the ip address
if ( is_string($ip) ) $ip = self::safeIp2long($ip);
if ( $this->totalBlocks == 0 ) {
//check and open the original db file
if ( $this->dbFileHandler == NULL ) {
$this->dbFileHandler = fopen($this->dbFile, 'r');
if ( $this->dbFileHandler == false ) {
throw new Exception("Fail to open the db file {$this->dbFile}");
}
}
fseek($this->dbFileHandler, 0);
$superBlock = fread($this->dbFileHandler, 8);
$this->firstIndexPtr = self::getLong($superBlock, 0);
$this->lastIndexPtr = self::getLong($superBlock, 4);
$this->totalBlocks = ($this->lastIndexPtr-$this->firstIndexPtr)/INDEX_BLOCK_LENGTH + 1;
}
//binary search to define the data
$l = 0;
$h = $this->totalBlocks;
$dataPtr = 0;
while ( $l <= $h ) {
$m = (($l + $h) >> 1);
$p = $m * INDEX_BLOCK_LENGTH;
fseek($this->dbFileHandler, $this->firstIndexPtr + $p);
$buffer = fread($this->dbFileHandler, INDEX_BLOCK_LENGTH);
$sip = self::getLong($buffer, 0);
if ( $ip < $sip ) {
$h = $m - 1;
} else {
$eip = self::getLong($buffer, 4);
if ( $ip > $eip ) {
$l = $m + 1;
} else {
$dataPtr = self::getLong($buffer, 8);
break;
}
}
}
//not matched just stop it here
if ( $dataPtr == 0 ) return NULL;
//get the data
$dataLen = (($dataPtr >> 24) & 0xFF);
$dataPtr = ($dataPtr & 0x00FFFFFF);
fseek($this->dbFileHandler, $dataPtr);
$data = fread($this->dbFileHandler, $dataLen);
return array(
'city_id' => self::getLong($data, 0),
'region' => substr($data, 4)
);
}
/**
* get the data block associated with the specified ip with b-tree search algorithm
* @Note: not thread safe
*
* @param ip
* @return Mixed Array for NULL for any error
*/
public function btreeSearch( $ip )
{
if ( is_string($ip) ) $ip = self::safeIp2long($ip);
//check and load the header
if ( $this->HeaderSip == NULL ) {
//check and open the original db file
if ( $this->dbFileHandler == NULL ) {
$this->dbFileHandler = fopen($this->dbFile, 'r');
if ( $this->dbFileHandler == false ) {
throw new Exception("Fail to open the db file {$this->dbFile}");
}
}
fseek($this->dbFileHandler, 8);
$buffer = fread($this->dbFileHandler, TOTAL_HEADER_LENGTH);
//fill the header
$idx = 0;
$this->HeaderSip = array();
$this->HeaderPtr = array();
for ( $i = 0; $i < TOTAL_HEADER_LENGTH; $i += 8 ) {
$startIp = self::getLong($buffer, $i);
$dataPtr = self::getLong($buffer, $i + 4);
if ( $dataPtr == 0 ) break;
$this->HeaderSip[] = $startIp;
$this->HeaderPtr[] = $dataPtr;
$idx++;
}
$this->headerLen = $idx;
}
//1. define the index block with the binary search
$l = 0; $h = $this->headerLen; $sptr = 0; $eptr = 0;
while ( $l <= $h ) {
$m = (($l + $h) >> 1);
//perfetc matched, just return it
if ( $ip == $this->HeaderSip[$m] ) {
if ( $m > 0 ) {
$sptr = $this->HeaderPtr[$m-1];
$eptr = $this->HeaderPtr[$m ];
} else {
$sptr = $this->HeaderPtr[$m ];
$eptr = $this->HeaderPtr[$m+1];
}
break;
}
//less then the middle value
if ( $ip < $this->HeaderSip[$m] ) {
if ( $m == 0 ) {
$sptr = $this->HeaderPtr[$m ];
$eptr = $this->HeaderPtr[$m+1];
break;
} else if ( $ip > $this->HeaderSip[$m-1] ) {
$sptr = $this->HeaderPtr[$m-1];
$eptr = $this->HeaderPtr[$m ];
break;
}
$h = $m - 1;
} else {
if ( $m == $this->headerLen - 1 ) {
$sptr = $this->HeaderPtr[$m-1];
$eptr = $this->HeaderPtr[$m ];
break;
} else if ( $ip <= $this->HeaderSip[$m+1] ) {
$sptr = $this->HeaderPtr[$m ];
$eptr = $this->HeaderPtr[$m+1];
break;
}
$l = $m + 1;
}
}
//match nothing just stop it
if ( $sptr == 0 ) return NULL;
//2. search the index blocks to define the data
$blockLen = $eptr - $sptr;
fseek($this->dbFileHandler, $sptr);
$index = fread($this->dbFileHandler, $blockLen + INDEX_BLOCK_LENGTH);
$dataPtr = 0;
$l = 0; $h = $blockLen / INDEX_BLOCK_LENGTH;
while ( $l <= $h ) {
$m = (($l + $h) >> 1);
$p = (int)($m * INDEX_BLOCK_LENGTH);
$sip = self::getLong($index, $p);
if ( $ip < $sip ) {
$h = $m - 1;
} else {
$eip = self::getLong($index, $p + 4);
if ( $ip > $eip ) {
$l = $m + 1;
} else {
$dataPtr = self::getLong($index, $p + 8);
break;
}
}
}
//not matched
if ( $dataPtr == 0 ) return NULL;
//3. get the data
$dataLen = (($dataPtr >> 24) & 0xFF);
$dataPtr = ($dataPtr & 0x00FFFFFF);
fseek($this->dbFileHandler, $dataPtr);
$data = fread($this->dbFileHandler, $dataLen);
return array(
'city_id' => self::getLong($data, 0),
'region' => substr($data, 4)
);
}
/**
* safe self::safeIp2long function
*
* @param ip
* */
public static function safeIp2long($ip)
{
$ip = ip2long($ip);
// convert signed int to unsigned int if on 32 bit operating system
if ($ip < 0 && PHP_INT_SIZE == 4) {
$ip = sprintf("%u", $ip);
}
return $ip;
}
/**
* read a long from a byte buffer
*
* @param b
* @param offset
*/
public static function getLong( $b, $offset )
{
$val = (
(ord($b[$offset++])) |
(ord($b[$offset++]) << 8) |
(ord($b[$offset++]) << 16) |
(ord($b[$offset ]) << 24)
);
// convert signed int to unsigned int if on 32 bit operating system
if ($val < 0 && PHP_INT_SIZE == 4) {
$val = sprintf("%u", $val);
}
return $val;
}
/**
* destruct method, resource destroy
*/
public function __destruct()
{
if ( $this->dbFileHandler != NULL ) {
fclose($this->dbFileHandler);
}
$this->dbBinStr = NULL;
$this->HeaderSip = NULL;
$this->HeaderPtr = NULL;
}
}