Fixed bit shifting

binlog/connection.go

@@ -8,6 +8,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"net"
+	"reflect"
 	"time"
 )
 
@@ -252,3 +253,35 @@ func (c *Conn) encLenEncInt(v uint64) []byte {
 	b = append(prefix, b...)
 	return b
 }
+
+func (c *Conn) bitmaskToStruct(b []byte, s interface{}) interface{} {
+	l := len(b)
+	t := reflect.TypeOf(s)
+	v := reflect.New(t.Elem()).Elem()
+	for i := uint(0); i < uint(v.NumField()); i++ {
+		f := v.Field(int(i))
+		var v bool
+		switch {
+		case l > 4:
+			x := binary.LittleEndian.Uint64(b)
+			flag := uint64(1 << i)
+			v = x&flag > 0
+		case l > 2:
+			x := binary.LittleEndian.Uint32(b)
+			flag := uint32(1 << i)
+			v = x&flag > 0
+		case l > 1:
+			x := binary.LittleEndian.Uint16(b)
+			flag := uint16(1 << i)
+			v = x&flag > 0
+		default:
+			x := uint(b[0])
+			flag := uint(1 << i)
+			v = x&flag > 0
+		}
+
+		f.SetBool(v)
+	}
+
+	return v.Interface()
+}

binlog/handshake.go

@@ -3,7 +3,6 @@ package binlog
 import (
 	"bytes"
 	"encoding/binary"
-	"reflect"
 )
 
 type Capabilities struct {
@@ -84,39 +83,14 @@ type HandshakeResponse struct {
 	KeyValues          map[string]string
 }
 
-func bitmaskToStruct(b []byte, t reflect.Type) interface{} {
-	l := len(b)
-	var x uint64
-	switch {
-	case l > 32:
-		x = uint64(binary.LittleEndian.Uint64(b))
-	case l > 16:
-		x = uint64(binary.LittleEndian.Uint32(b))
-	case l > 8:
-		x = uint64(binary.LittleEndian.Uint16(b))
-	default:
-		x = uint64(uint(b[0]))
-	}
-
-	v := reflect.New(t.Elem()).Elem()
-	for i := 0; i < v.NumField(); i++ {
-		f := v.Field(i)
-		flag := uint64(1 << uint(i))
-		v := x&flag > 0
-		f.SetBool(v)
-	}
-
-	return v.Interface()
-}
-
 func (c *Conn) decodeCapabilityFlags(hs *Handshake) {
 	var cfb = append(hs.CapabilityFlags1, hs.CapabilityFlags2...)
-	capabilities := bitmaskToStruct(cfb, reflect.TypeOf(hs.Capabilities)).(Capabilities)
+	capabilities := c.bitmaskToStruct(cfb, hs.Capabilities).(Capabilities)
 	hs.Capabilities = &capabilities
 }
 
 func (c *Conn) decodeStatusFlags(hs *Handshake) {
-	status := bitmaskToStruct(hs.StatusFlags, reflect.TypeOf(hs.Status)).(Status)
+	status := c.bitmaskToStruct(hs.StatusFlags, hs.Status).(Status)
 	hs.Status = &status
 }
 
@@ -204,7 +178,6 @@ func (c *Conn) decodeHandshakePacket() error {
 	}
 
 	c.Handshake = &packet
-
 	return nil
 }