refactor(重构代码): 重构并保持接口兼容

2026-01-11 08:00:21 +08:00 · 2026-01-08 11:14:24 +08:00
parent cc141ac4f5
commit 999c6f1442
11 changed files with 511 additions and 261 deletions
--- a/qqwry_dat.go
+++ b/qqwry_dat.go
@@ -0,0 +1,141 @@
+package qqwry
+
+import (
+	"encoding/binary"
+	"errors"
+	"net"
+	"strings"
+
+	"golang.org/x/text/encoding/simplifiedchinese"
+	"golang.org/x/text/transform"
+)
+
+const (
+	indexLen      = 7
+	redirectMode1 = 0x01
+	redirectMode2 = 0x02
+)
+
+// byte3ToUInt32 将3字节切片转换为uint32
+// 入参: data 3字节切片
+// 返回: uint32转换后的值
+func byte3ToUInt32(data []byte) uint32 {
+	i := uint32(data[0]) & 0xff
+	i |= (uint32(data[1]) << 8) & 0xff00
+	i |= (uint32(data[2]) << 16) & 0xff0000
+	return i
+}
+
+// gb18030Decode 将GB18030编码解码为UTF-8
+// 入参: src GB18030编码的字节切片
+// 返回: string UTF-8编码的字符串
+func gb18030Decode(src []byte) string {
+	d, _, _ := transform.Bytes(simplifiedchinese.GB18030.NewDecoder(), src)
+	return string(d)
+}
+
+// queryIPDat 从DAT数据库查询IP
+// 入参: ipv4 IPv4地址
+// 返回: location 位置信息, err 错误信息
+func (c *Client) queryIPDat(ipv4 string) (location *Location, err error) {
+	ip := net.ParseIP(ipv4).To4()
+	if ip == nil {
+		return nil, errors.New("ip is not ipv4")
+	}
+	ip32 := binary.BigEndian.Uint32(ip)
+	posA := binary.LittleEndian.Uint32(c.data[:4])
+	posZ := binary.LittleEndian.Uint32(c.data[4:8])
+	var offset uint32 = 0
+	for {
+		mid := posA + (((posZ-posA)/indexLen)>>1)*indexLen
+		buf := c.data[mid : mid+indexLen]
+		_ip := binary.LittleEndian.Uint32(buf[:4])
+		if posZ-posA == indexLen {
+			offset = byte3ToUInt32(buf[4:])
+			buf = c.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 nil, errors.New("ip not found")
+	}
+	posM := offset + 4
+	mode := c.data[posM]
+	var ispPos uint32
+	var addr, isp string
+	switch mode {
+	case redirectMode1:
+		posC := byte3ToUInt32(c.data[posM+1 : posM+4])
+		mode = c.data[posC]
+		posCA := posC
+		if mode == redirectMode2 {
+			posCA = byte3ToUInt32(c.data[posC+1 : posC+4])
+			posC += 4
+		}
+		for i := posCA; i < c.dataLen; i++ {
+			if c.data[i] == 0 {
+				addr = string(c.data[posCA:i])
+				break
+			}
+		}
+		if mode != redirectMode2 {
+			posC += uint32(len(addr) + 1)
+		}
+		ispPos = posC
+	case redirectMode2:
+		posCA := byte3ToUInt32(c.data[posM+1 : posM+4])
+		for i := posCA; i < c.dataLen; i++ {
+			if c.data[i] == 0 {
+				addr = string(c.data[posCA:i])
+				break
+			}
+		}
+		ispPos = offset + 8
+	default:
+		posCA := offset + 4
+		for i := posCA; i < c.dataLen; i++ {
+			if c.data[i] == 0 {
+				addr = string(c.data[posCA:i])
+				break
+			}
+		}
+		ispPos = offset + uint32(5+len(addr))
+	}
+	if addr != "" {
+		addr = strings.TrimSpace(gb18030Decode([]byte(addr)))
+	}
+	ispMode := c.data[ispPos]
+	if ispMode == redirectMode1 || ispMode == redirectMode2 {
+		ispPos = byte3ToUInt32(c.data[ispPos+1 : ispPos+4])
+	}
+	if ispPos > 0 {
+		for i := ispPos; i < c.dataLen; i++ {
+			if c.data[i] == 0 {
+				isp = string(c.data[ispPos:i])
+				if isp != "" {
+					if strings.Contains(isp, "CZ88.NET") {
+						isp = ""
+					} else {
+						isp = strings.TrimSpace(gb18030Decode([]byte(isp)))
+					}
+				}
+				break
+			}
+		}
+	}
+	location = SplitResult(addr, isp, ipv4)
+	return location, nil
+}