<?php
class ipdbv6 {
	public $file;
	public $fd;
	public $total;
	public $db4;
	// 索引区
	public $index_start_offset;
	public $index_end_offset;
	public $offlen;
	public $iplen;
	public function __construct($file="ipv6wry.db", $dbipv4=null) {
		if (PHP_INT_SIZE < 8) {
			die("本程序不支持PHP_INT_SIZE小于8的环境，请使用64位PHP。Windows系统请使用7.0.0以上版本。");
		}
		if (version_compare(PHP_VERSION, "5.6.3", "<")){
			die("您的PHP版本过低，请使用5.6.3以上版本。");
		}
		if (!file_exists($file) or !is_readable($file)) {
			throw new Exception("{$file} does not exist, or is not readable");
		}
		$this->file = $file;
		$this->fd = fopen($file, "rb");
		$this->index_start_offset = $this->read8(16);
		$this->offlen = $this->read1(6);
		$this->iplen = $this->read1(7);
		$this->total = $this->read8(8);
		$this->index_end_offset = $this->index_start_offset + ($this->iplen + $this->offlen) * $this->total;
		$db4 = $dbipv4;
	}
	public function query($ip) {
		$ip_bin = inet_pton($ip);
		if ($ip_bin == false) {
			throw new Exception("错误或不完整的IP地址: $ip");
		}
		if (strlen($ip_bin) != 16) {
			throw new Exception("错误或不完整的IPv6地址: $ip");
		}
		$ip_num_arr = unpack("J2", $ip_bin);
		$ip_num1 = $ip_num_arr[1];
		$ip_num2 = $ip_num_arr[2];
		$ip_find = $this->find($ip_num1, $ip_num2, 0, $this->total);
		$ip_offset = $this->index_start_offset + $ip_find * ($this->iplen + $this->offlen);
		$ip_offset2 = $ip_offset + $this->iplen + $this->offlen;
		$ip_start = inet_ntop(pack("J2", $this->read8($ip_offset), 0));
		try {
			$ip_end = inet_ntop(pack("J2", $this->read8($ip_offset2) - 1, 0));
		} catch (Exception $e) {
			$ip_end = "FFFF:FFFF:FFFF:FFFF::";
		}
		$ip_record_offset = $this->read8($ip_offset + $this->iplen, $this->offlen);
		$ip_addr = $this->read_record($ip_record_offset);
		$ip_addr_disp = $ip_addr[0] . " " . $ip_addr[1];
		return array("start" => $ip_start, "end" => $ip_end, "addr" => $ip_addr, "disp" => $ip_addr_disp);
	}
	/**
	 * 读取记录
	 */
	public function read_record($offset) {
		$record = array(0 => "", 1 => "");
		$flag = $this->read1($offset);
		if ($flag == 1) {
			$location_offset = $this->read8($offset + 1, $this->offlen);
			return read_record($location_offset);
		} else {
			$record[0] = $this->read_location($offset);
			if ($flag == 2) {
				$record[1] = $this->read_location($offset + $this->offlen + 1);
			} else {
				$record[1] = $this->read_location($offset + strlen($record[0]) + 1);
			}
		}
		return $record;
	}
	/**
	 * 读取地区
	 */
	public function read_location($offset) {
		if ($offset == 0) {
			return "";
		}
		$flag = $this->read1($offset);
		// 出错
		if ($flag == 0) {
			return "";
		}
		// 仍然为重定向
		if ($flag == 2) {
			$offset = $this->read8($offset + 1, $this->offlen);
			return $this->read_location($offset);
		}
		$location = $this->readstr($offset);
		return $location;
	}
	/**
	 * 查找 ip 所在的索引
	 */
	public function find($ip_num1, $ip_num2, $l, $r) {
		if ($l + 1 >= $r) {
			return $l;
		}
		$m = intval(($l + $r) / 2);
		$m_ip1 = $this->read8($this->index_start_offset + $m * ($this->iplen + $this->offlen), $this->iplen);
		$m_ip2 = 0;
		if ($this->iplen <= 8) {
			$m_ip1 <<= 8 * (8 - $this->iplen);
		} else {
			$m_ip2 = $this->read8($this->index_start_offset + $m * ($this->iplen + $this->offlen) + 8, $this->iplen - 8);
			$m_ip2 <<= 8 * (16 - $this->iplen);
		}
		if ($this->uint64cmp($ip_num1, $m_ip1) < 0) {
			return $this->find($ip_num1, $ip_num2, $l, $m);
		} else if ($this->uint64cmp($ip_num1, $m_ip1) > 0) {
			return $this->find($ip_num1, $ip_num2, $m, $r);
		} else if ($this->uint64cmp($ip_num2, $m_ip2) < 0) {
			return $this->find($ip_num1, $ip_num2, $l, $m);
		} else {
			return $this->find($ip_num1, $ip_num2, $m, $r);
		}
	}
	public function readraw($offset=null, $size=0) {
		if (!is_null($offset)) {
			fseek($this->fd, $offset);
		}
		return fread($this->fd, $size);
	}
	public function read1($offset=null) {
		if (!is_null($offset)) {
			fseek($this->fd, $offset);
		}
		$a = fread($this->fd, 1);
		return @unpack("C", $a)[1];
	}
	public function read8($offset=null, $size=8) {
		if (!is_null($offset)) {
			fseek($this->fd, $offset);
		}
		$a = fread($this->fd, $size) . "\0\0\0\0\0\0\0\0";
		return @unpack("P", $a)[1];
	}
	public function readstr($offset=null) {
		if (!is_null($offset)) {
			fseek($this->fd, $offset);
		}
		$str = "";
		$chr = $this->read1($offset);
		while ($chr != 0) {
			$str .= chr($chr);
			$offset++;
			$chr = $this->read1($offset);
		}
		return $str;
	}
	public function ip2num($ip) {
		return unpack("N", inet_pton($ip))[1];
	}
	public function inet_ntoa($nip) {
		$ip = array();
		for ($i=3; $i > 0; $i--) { 
			$ip_seg = intval($nip/pow(256, $i));
			$ip[] = $ip_seg;
			$nip -= $ip_seg * pow(256, $i);
		}
		$ip[] = $nip;
		return join(".", $ip);
	}
	public function uint64cmp($a, $b) {
		if ($a >= 0 && $b >= 0 || $a < 0 && $b < 0) {
			return $a <=> $b;
		} else if ($a >= 0 && $b < 0) {
			return -1;
		} else if ($a < 0 && $b >= 0) {
			return 1;
		}
	}
	public function __destruct() {
		if ($this->fd) {
			fclose($this->fd);
		}
	}
}
?>
