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ip2region_private
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Add btree memory search method

This commit is contained in:
GaoShangheng 2018-08-25 23:04:55 +08:00
parent f482591eee
commit d4512c744e
1 changed files with 121 additions and 0 deletions
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121
binding/php/Ip2Region.class.php
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@ -301,6 +301,127 @@ class Ip2Region
);
}
public function btreeMemorySearch( $ip )
{
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);
//check and load the header
if ( $this->HeaderSip == NULL ) {
$buffer = substr($this->dbBinStr,8,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;
$index =substr($this->dbBinStr,$sptr, $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);
$data =substr($this->dbBinStr,$dataPtr, $dataLen);
return array(
'city_id' => self::getLong($data, 0),
'region' => substr($data, 4)
);
}
/**
* safe self::safeIp2long function