add other session providers (#5963)

vendor/github.com/lunny/nodb/util.go

@@ -0,0 +1,113 @@
+package nodb
+
+import (
+	"encoding/binary"
+	"errors"
+	"reflect"
+	"strconv"
+	"unsafe"
+)
+
+var errIntNumber = errors.New("invalid integer")
+
+// no copy to change slice to string
+// use your own risk
+func String(b []byte) (s string) {
+	pbytes := (*reflect.SliceHeader)(unsafe.Pointer(&b))
+	pstring := (*reflect.StringHeader)(unsafe.Pointer(&s))
+	pstring.Data = pbytes.Data
+	pstring.Len = pbytes.Len
+	return
+}
+
+// no copy to change string to slice
+// use your own risk
+func Slice(s string) (b []byte) {
+	pbytes := (*reflect.SliceHeader)(unsafe.Pointer(&b))
+	pstring := (*reflect.StringHeader)(unsafe.Pointer(&s))
+	pbytes.Data = pstring.Data
+	pbytes.Len = pstring.Len
+	pbytes.Cap = pstring.Len
+	return
+}
+
+func Int64(v []byte, err error) (int64, error) {
+	if err != nil {
+		return 0, err
+	} else if v == nil || len(v) == 0 {
+		return 0, nil
+	} else if len(v) != 8 {
+		return 0, errIntNumber
+	}
+
+	return int64(binary.LittleEndian.Uint64(v)), nil
+}
+
+func PutInt64(v int64) []byte {
+	var b []byte
+	pbytes := (*reflect.SliceHeader)(unsafe.Pointer(&b))
+	pbytes.Data = uintptr(unsafe.Pointer(&v))
+	pbytes.Len = 8
+	pbytes.Cap = 8
+	return b
+}
+
+func StrInt64(v []byte, err error) (int64, error) {
+	if err != nil {
+		return 0, err
+	} else if v == nil {
+		return 0, nil
+	} else {
+		return strconv.ParseInt(String(v), 10, 64)
+	}
+}
+
+func StrInt32(v []byte, err error) (int32, error) {
+	if err != nil {
+		return 0, err
+	} else if v == nil {
+		return 0, nil
+	} else {
+		res, err := strconv.ParseInt(String(v), 10, 32)
+		return int32(res), err
+	}
+}
+
+func StrInt8(v []byte, err error) (int8, error) {
+	if err != nil {
+		return 0, err
+	} else if v == nil {
+		return 0, nil
+	} else {
+		res, err := strconv.ParseInt(String(v), 10, 8)
+		return int8(res), err
+	}
+}
+
+func StrPutInt64(v int64) []byte {
+	return strconv.AppendInt(nil, v, 10)
+}
+
+func MinUInt32(a uint32, b uint32) uint32 {
+	if a > b {
+		return b
+	} else {
+		return a
+	}
+}
+
+func MaxUInt32(a uint32, b uint32) uint32 {
+	if a > b {
+		return a
+	} else {
+		return b
+	}
+}
+
+func MaxInt32(a int32, b int32) int32 {
+	if a > b {
+		return a
+	} else {
+		return b
+	}
+}