go-json/decode_interface.go

125 lines
3.3 KiB
Go

package json
import (
"errors"
"reflect"
"unsafe"
)
type interfaceDecoder struct {
typ *rtype
dummy unsafe.Pointer // for escape value
}
func newInterfaceDecoder(typ *rtype) *interfaceDecoder {
return &interfaceDecoder{typ: typ}
}
var (
interfaceMapType = type2rtype(
reflect.TypeOf((*map[interface{}]interface{})(nil)).Elem(),
)
)
func (d *interfaceDecoder) decode(buf []byte, cursor int, p uintptr) (int, error) {
cursor = skipWhiteSpace(buf, cursor)
switch buf[cursor] {
case '{':
var v map[interface{}]interface{}
ptr := unsafe.Pointer(&v)
d.dummy = ptr
dec := newMapDecoder(interfaceMapType, newInterfaceDecoder(d.typ), newInterfaceDecoder(d.typ))
cursor, err := dec.decode(buf, cursor, uintptr(ptr))
if err != nil {
return 0, err
}
*(*interface{})(unsafe.Pointer(p)) = v
return cursor, nil
case '[':
var v []interface{}
ptr := unsafe.Pointer(&v)
d.dummy = ptr // escape ptr
dec := newSliceDecoder(newInterfaceDecoder(d.typ), d.typ, d.typ.Size())
cursor, err := dec.decode(buf, cursor, uintptr(ptr))
if err != nil {
return 0, err
}
*(*interface{})(unsafe.Pointer(p)) = v
return cursor, nil
case '-', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
return newFloatDecoder(func(p uintptr, v float64) {
*(*interface{})(unsafe.Pointer(p)) = v
}).decode(buf, cursor, p)
case '"':
cursor++
start := cursor
for {
switch buf[cursor] {
case '\\':
cursor++
case '"':
literal := buf[start:cursor]
cursor++
*(*interface{})(unsafe.Pointer(p)) = *(*string)(unsafe.Pointer(&literal))
return cursor, nil
case '\000':
return 0, errors.New("unexpected error string")
}
cursor++
}
return 0, errors.New("unexpected error string")
case 't':
if cursor+3 >= len(buf) {
return 0, errors.New("unexpected error. invalid bool character")
}
if buf[cursor+1] != 'r' {
return 0, errors.New("unexpected error. invalid bool character")
}
if buf[cursor+2] != 'u' {
return 0, errors.New("unexpected error. invalid bool character")
}
if buf[cursor+3] != 'e' {
return 0, errors.New("unexpected error. invalid bool character")
}
cursor += 4
*(*interface{})(unsafe.Pointer(p)) = true
return cursor, nil
case 'f':
if cursor+4 >= len(buf) {
return 0, errors.New("unexpected error. invalid bool character")
}
if buf[cursor+1] != 'a' {
return 0, errors.New("unexpected error. invalid bool character")
}
if buf[cursor+2] != 'l' {
return 0, errors.New("unexpected error. invalid bool character")
}
if buf[cursor+3] != 's' {
return 0, errors.New("unexpected error. invalid bool character")
}
if buf[cursor+4] != 'e' {
return 0, errors.New("unexpected error. invalid bool character")
}
cursor += 5
*(*interface{})(unsafe.Pointer(p)) = false
return cursor, nil
case 'n':
if cursor+3 >= len(buf) {
return 0, errors.New("unexpected error. invalid bool character")
}
if buf[cursor+1] != 'u' {
return 0, errors.New("unexpected error. invalid bool character")
}
if buf[cursor+2] != 'l' {
return 0, errors.New("unexpected error. invalid bool character")
}
if buf[cursor+3] != 'l' {
return 0, errors.New("unexpected error. invalid bool character")
}
cursor += 4
*(*interface{})(unsafe.Pointer(p)) = nil
return cursor, nil
}
return cursor, errors.New("unexpected error value")
}