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base64.go
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base64.go
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// based on https://github.com/powturbo/Turbo-Base64
package base64
import "errors"
type Encoding struct {
lutSe [64]byte
lutXe [4096]uint32
lutXd0 [256]uint32
lutXd1 [256]uint32
lutXd2 [256]uint32
lutXd3 [256]uint32
pad bool
}
func (e *Encoding) EncodedLen(n int) int {
if !e.pad {
return (n*8 + 5) / 6
}
return (n + 2) / 3 * 4
}
func (e *Encoding) Encode(dst []byte, src []byte) {
if len(src) == 0 {
return
}
e.encode(dst, src, uintptr(e.EncodedLen(len(src))))
}
func (e *Encoding) EncodeToBytes(src []byte) []byte {
if len(src) == 0 {
return []byte{}
}
length := e.EncodedLen(len(src))
result := make([]byte, length)
e.encode(result, src, uintptr(length))
return result
}
func (e *Encoding) EncodeToString(src []byte) string {
return b2s(e.EncodeToBytes(src))
}
func (e *Encoding) EncodeString(src string) []byte {
return e.EncodeToBytes(s2b(src))
}
func (e *Encoding) EncodeStringToString(src string) string {
return b2s(e.EncodeToBytes(s2b(src)))
}
func (e *Encoding) DecodedLen(n int) int {
if !e.pad {
return n * 6 / 8
}
return n / 4 * 3
}
func (e *Encoding) Decode(dst []byte, src []byte) (int, error) {
if len(src) == 0 {
return 0, nil
}
n := e.decode(dst, src)
if n == 0 {
return 0, errors.New("wrong base64 data")
}
return n, nil
}
func (e *Encoding) DecodeToBytes(src []byte) ([]byte, error) {
if len(src) == 0 {
return []byte{}, nil
}
length := e.DecodedLen(len(src))
if length == 0 {
return nil, errors.New("wrong base64 data")
}
result := make([]byte, length)
n := e.decode(result, src)
if n == 0 {
return nil, errors.New("wrong base64 data")
}
return result[:n], nil
}
func (e *Encoding) DecodeToString(src []byte) (string, error) {
result, err := e.DecodeToBytes(src)
if err != nil {
return "", err
}
return b2s(result), nil
}
func (e *Encoding) DecodeString(src string) ([]byte, error) {
return e.DecodeToBytes(s2b(src))
}
func (e *Encoding) DecodeStringToString(src string) (string, error) {
result, err := e.DecodeToBytes(s2b(src))
if err != nil {
return "", err
}
return b2s(result), nil
}
func NewEncoding(lutSe [64]byte, pad bool) *Encoding {
lutXe, lutXd0, lutXd1, lutXd2, lutXd3 := makeLuts(lutSe)
return &Encoding{
lutSe: lutSe,
lutXe: lutXe,
lutXd0: lutXd0,
lutXd1: lutXd1,
lutXd2: lutXd2,
lutXd3: lutXd3,
pad: pad,
}
}
var (
StdEncoding = NewEncoding(stdLutSe, true)
RawStdEncoding = NewEncoding(stdLutSe, false)
URLEncoding = NewEncoding(urlLutSe, true)
RawURLEncoding = NewEncoding(urlLutSe, false)
)