go-json/decode_bytes.go

138 lines
2.8 KiB
Go

package json
import (
"encoding/base64"
"unsafe"
)
type bytesDecoder struct {
structName string
fieldName string
}
func newBytesDecoder(structName string, fieldName string) *bytesDecoder {
return &bytesDecoder{structName: structName, fieldName: fieldName}
}
func (d *bytesDecoder) decodeStream(s *stream, p unsafe.Pointer) error {
bytes, err := d.decodeStreamBinary(s)
if err != nil {
return err
}
if bytes == nil {
s.reset()
return nil
}
decodedLen := base64.StdEncoding.DecodedLen(len(bytes))
buf := make([]byte, decodedLen)
if _, err := base64.StdEncoding.Decode(buf, bytes); err != nil {
return err
}
*(*[]byte)(p) = buf
s.reset()
return nil
}
func (d *bytesDecoder) decode(buf []byte, cursor int64, p unsafe.Pointer) (int64, error) {
bytes, c, err := d.decodeBinary(buf, cursor)
if err != nil {
return 0, err
}
cursor = c
decodedLen := base64.StdEncoding.DecodedLen(len(bytes))
b := make([]byte, decodedLen)
if _, err := base64.StdEncoding.Decode(b, bytes); err != nil {
return 0, err
}
*(*[]byte)(p) = b
return cursor, nil
}
func binaryBytes(s *stream) ([]byte, error) {
s.cursor++
start := s.cursor
for {
switch s.char() {
case '"':
literal := s.buf[start:s.cursor]
s.cursor++
return literal, nil
case nul:
if s.read() {
continue
}
goto ERROR
}
s.cursor++
}
ERROR:
return nil, errUnexpectedEndOfJSON("[]byte", s.totalOffset())
}
func (d *bytesDecoder) decodeStreamBinary(s *stream) ([]byte, error) {
for {
switch s.char() {
case ' ', '\n', '\t', '\r':
s.cursor++
continue
case '"':
return binaryBytes(s)
case 'n':
if err := nullBytes(s); err != nil {
return nil, err
}
return nil, nil
case nul:
if s.read() {
continue
}
}
break
}
return nil, errNotAtBeginningOfValue(s.totalOffset())
}
func (d *bytesDecoder) decodeBinary(buf []byte, cursor int64) ([]byte, int64, error) {
for {
switch buf[cursor] {
case ' ', '\n', '\t', '\r':
cursor++
case '"':
cursor++
start := cursor
for {
switch buf[cursor] {
case '"':
literal := buf[start:cursor]
cursor++
return literal, cursor, nil
case nul:
return nil, 0, errUnexpectedEndOfJSON("[]byte", cursor)
}
cursor++
}
return nil, 0, errUnexpectedEndOfJSON("[]byte", cursor)
case 'n':
buflen := int64(len(buf))
if cursor+3 >= buflen {
return nil, 0, errUnexpectedEndOfJSON("null", cursor)
}
if buf[cursor+1] != 'u' {
return nil, 0, errInvalidCharacter(buf[cursor+1], "null", cursor)
}
if buf[cursor+2] != 'l' {
return nil, 0, errInvalidCharacter(buf[cursor+2], "null", cursor)
}
if buf[cursor+3] != 'l' {
return nil, 0, errInvalidCharacter(buf[cursor+3], "null", cursor)
}
cursor += 4
return []byte{}, cursor, nil
default:
goto ERROR
}
}
ERROR:
return nil, 0, errNotAtBeginningOfValue(cursor)
}