go-json/decode_struct.go

75 lines
1.5 KiB
Go

package json
import (
"errors"
"unsafe"
)
type structFieldSet struct {
dec decoder
offset uintptr
}
type structDecoder struct {
fieldMap map[string]*structFieldSet
keyDecoder *stringDecoder
}
func newStructDecoder(fieldMap map[string]*structFieldSet) *structDecoder {
return &structDecoder{
fieldMap: fieldMap,
keyDecoder: newStringDecoder(),
}
}
func (d *structDecoder) decode(buf []byte, cursor int, p uintptr) (int, error) {
buflen := len(buf)
cursor = skipWhiteSpace(buf, cursor)
if buflen < 2 {
return 0, errors.New("unexpected error {}")
}
if buf[cursor] != '{' {
return 0, errors.New("unexpected error {")
}
cursor++
for ; cursor < buflen; cursor++ {
key, c, err := d.keyDecoder.decodeByte(buf, cursor)
if err != nil {
return 0, err
}
cursor = c
cursor = skipWhiteSpace(buf, cursor)
if buf[cursor] != ':' {
return 0, errors.New("unexpected error invalid delimiter for object")
}
cursor++
if cursor >= buflen {
return 0, errors.New("unexpected error missing value")
}
k := *(*string)(unsafe.Pointer(&key))
field, exists := d.fieldMap[k]
if exists {
c, err := field.dec.decode(buf, cursor, p+field.offset)
if err != nil {
return 0, err
}
cursor = c
} else {
c, err := skipValue(buf, cursor)
if err != nil {
return 0, err
}
cursor = c
}
cursor = skipWhiteSpace(buf, cursor)
if buf[cursor] == '}' {
cursor++
return cursor, nil
}
if buf[cursor] != ',' {
return 0, errors.New("unexpected error ,")
}
}
return cursor, nil
}