diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..731ab49
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,4 @@
+.idea/
+.vscode/
+.devcontainer/
+qqwry.dat
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..ca17b57
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,5 @@
+module github.com/xiaoqidun/qqwry
+
+go 1.16
+
+require golang.org/x/text v0.3.5
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..bbd33e8
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,3 @@
+golang.org/x/text v0.3.5 h1:i6eZZ+zk0SOf0xgBpEpPD18qWcJda6q1sxt3S0kzyUQ=
+golang.org/x/text v0.3.5/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
diff --git a/qqwry.go b/qqwry.go
new file mode 100644
index 0000000..2882ba4
--- /dev/null
+++ b/qqwry.go
@@ -0,0 +1,161 @@
+package qqwry
+
+import (
+	"bytes"
+	_ "embed"
+	"encoding/binary"
+	"errors"
+	"golang.org/x/text/encoding/simplifiedchinese"
+	"golang.org/x/text/transform"
+	"io/ioutil"
+	"net"
+	"sync"
+)
+
+var (
+	data    []byte
+	dataLen uint32
+	ipCache = &sync.Map{}
+)
+
+const (
+	indexLen      = 7
+	redirectMode1 = 0x01
+	redirectMode2 = 0x02
+)
+
+type cache struct {
+	Country 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) (country string, area string, err error) {
+	if v, ok := ipCache.Load(queryIp); ok {
+		country = v.(cache).Country
+		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 {
+		return
+	}
+	posM := offset + 4
+	mode := data[posM]
+	var areaPos uint32
+	switch mode {
+	case redirectMode1:
+		posC := byte3ToUInt32(data[posM+1 : posM+4])
+		mode = data[posC]
+		var cA uint32 = 0
+		if mode == redirectMode2 {
+			cA = byte3ToUInt32(data[posC+1 : posC+4])
+			posC += 4
+		}
+		for i := cA; i < dataLen; i++ {
+			if data[i] == 0 {
+				country = string(data[cA:i])
+				break
+			}
+		}
+		if mode != redirectMode2 {
+			posC += uint32(len(country) + 1)
+		}
+		areaPos = posC
+	case redirectMode2:
+		cA := byte3ToUInt32(data[posM+1 : posM+4])
+		for i := cA; i < dataLen; i++ {
+			if data[i] == 0 {
+				country = string(data[cA:i])
+				break
+			}
+		}
+		areaPos = offset + 8
+	default:
+		cA := offset + 4
+		for i := cA; i < dataLen; i++ {
+			if data[i] == 0 {
+				country = string(data[cA:i])
+				break
+			}
+		}
+		areaPos = offset + uint32(5+len(country))
+	}
+	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
+			}
+		}
+	}
+	country = gb18030Decode([]byte(country))
+	area = gb18030Decode([]byte(area))
+	ipCache.Store(queryIp, cache{Country: country, 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
+}
diff --git a/qqwry_test.go b/qqwry_test.go
new file mode 100644
index 0000000..b2c7b87
--- /dev/null
+++ b/qqwry_test.go
@@ -0,0 +1,20 @@
+package qqwry
+
+import (
+	"testing"
+)
+
+func init() {
+	if err := LoadFile("qqwry.dat"); err != nil {
+		panic(err)
+	}
+}
+
+func TestQueryIP(t *testing.T) {
+	queryIp := "1.1.1.1"
+	country, area, err := QueryIP(queryIp)
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Log(country, area)
+}