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

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2019-02-05 09:52:51 -07:00
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
}
}