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package qqwry
import (
"bytes"
"encoding/binary"
"errors"
"golang.org/x/text/encoding/simplifiedchinese"
"golang.org/x/text/transform"
"io/ioutil"
"net"
"strings"
"sync"
)
var (
data []byte
dataLen uint32
ipCache = &sync.Map{}
)
const (
indexLen = 7
redirectMode1 = 0x01
redirectMode2 = 0x02
)
type cache struct {
City string
Area string
}
func byte3ToUInt32(data []byte) uint32 {
i := uint32(data[0]) & 0xff
i |= (uint32(data[1]) << 8) & 0xff00
i |= (uint32(data[2]) << 16) & 0xff0000
return i
}
func gb18030Decode(src []byte) string {
in := bytes.NewReader(src)
out := transform.NewReader(in, simplifiedchinese.GB18030.NewDecoder())
d, _ := ioutil.ReadAll(out)
return string(d)
}
// QueryIP 从内存或缓存查询IP
func QueryIP(queryIp string) (city string, area string, err error) {
if v, ok := ipCache.Load(queryIp); ok {
city = v.(cache).City
area = v.(cache).Area
return
}
ip := net.ParseIP(queryIp).To4()
if ip == nil {
err = errors.New("ip is not ipv4")
return
}
ip32 := binary.BigEndian.Uint32(ip)
posA := binary.LittleEndian.Uint32(data[:4])
posZ := binary.LittleEndian.Uint32(data[4:8])
var offset uint32 = 0
for {
mid := posA + (((posZ-posA)/indexLen)>>1)*indexLen
buf := data[mid : mid+indexLen]
_ip := binary.LittleEndian.Uint32(buf[:4])
if posZ-posA == indexLen {
offset = byte3ToUInt32(buf[4:])
buf = data[mid+indexLen : mid+indexLen+indexLen]
if ip32 < binary.LittleEndian.Uint32(buf[:4]) {
break
} else {
offset = 0
break
}
}
if _ip > ip32 {
posZ = mid
} else if _ip < ip32 {
posA = mid
} else if _ip == ip32 {
offset = byte3ToUInt32(buf[4:])
break
}
}
if offset <= 0 {
err = errors.New("ip not found")
return
}
posM := offset + 4
mode := data[posM]
var areaPos uint32
switch mode {
case redirectMode1:
posC := byte3ToUInt32(data[posM+1 : posM+4])
mode = data[posC]
posCA := posC
if mode == redirectMode2 {
posCA = byte3ToUInt32(data[posC+1 : posC+4])
posC += 4
}
for i := posCA; i < dataLen; i++ {
if data[i] == 0 {
city = string(data[posCA:i])
break
}
}
if mode != redirectMode2 {
posC += uint32(len(city) + 1)
}
areaPos = posC
case redirectMode2:
posCA := byte3ToUInt32(data[posM+1 : posM+4])
for i := posCA; i < dataLen; i++ {
if data[i] == 0 {
city = string(data[posCA:i])
break
}
}
areaPos = offset + 8
default:
posCA := offset + 4
for i := posCA; i < dataLen; i++ {
if data[i] == 0 {
city = string(data[posCA:i])
break
}
}
areaPos = offset + uint32(5+len(city))
}
areaMode := data[areaPos]
if areaMode == redirectMode1 || areaMode == redirectMode2 {
areaPos = byte3ToUInt32(data[areaPos+1 : areaPos+4])
}
if areaPos > 0 {
for i := areaPos; i < dataLen; i++ {
if data[i] == 0 {
area = string(data[areaPos:i])
break
}
}
}
if city != "" {
city = strings.TrimSpace(gb18030Decode([]byte(city)))
}
if area != "" {
if strings.Contains(area, "CZ88.NET") {
area = ""
} else {
area = strings.TrimSpace(gb18030Decode([]byte(area)))
}
}
ipCache.Store(queryIp, cache{City: city, Area: area})
return
}
// LoadData 从内存加载IP数据库
func LoadData(database []byte) {
data = database
dataLen = uint32(len(data))
}
// LoadFile 从文件加载IP数据库
func LoadFile(filepath string) (err error) {
data, err = ioutil.ReadFile(filepath)
if err != nil {
return
}
dataLen = uint32(len(data))
return
}