go-json/decode_map.go

83 lines
1.9 KiB
Go

package json
import (
"errors"
"unsafe"
)
type mapDecoder struct {
mapType *rtype
keyDecoder decoder
valueDecoder decoder
}
func newMapDecoder(mapType *rtype, keyDec decoder, valueDec decoder) *mapDecoder {
return &mapDecoder{
mapType: mapType,
keyDecoder: keyDec,
valueDecoder: valueDec,
}
}
//go:linkname makemap reflect.makemap
func makemap(*rtype, int) unsafe.Pointer
//go:linkname mapassign reflect.mapassign
//go:noescape
func mapassign(t *rtype, m unsafe.Pointer, key, val unsafe.Pointer)
func (d *mapDecoder) setKey(ctx *context, key interface{}) error {
header := (*interfaceHeader)(unsafe.Pointer(&key))
return d.keyDecoder.decode(ctx, uintptr(header.ptr))
}
func (d *mapDecoder) setValue(ctx *context, key interface{}) error {
header := (*interfaceHeader)(unsafe.Pointer(&key))
return d.valueDecoder.decode(ctx, uintptr(header.ptr))
}
func (d *mapDecoder) decode(ctx *context, p uintptr) error {
ctx.skipWhiteSpace()
buf := ctx.buf
buflen := ctx.buflen
cursor := ctx.cursor
if buflen < 2 {
return errors.New("unexpected error {}")
}
if buf[cursor] != '{' {
return errors.New("unexpected error {")
}
cursor++
mapValue := makemap(d.mapType, 0)
for ; cursor < buflen; cursor++ {
ctx.cursor = cursor
var key interface{}
if err := d.setKey(ctx, &key); err != nil {
return err
}
cursor = ctx.skipWhiteSpace()
if buf[cursor] != ':' {
return errors.New("unexpected error invalid delimiter for object")
}
cursor++
if cursor >= buflen {
return errors.New("unexpected error missing value")
}
ctx.cursor = cursor
var value interface{}
if err := d.setValue(ctx, &value); err != nil {
return err
}
mapassign(d.mapType, mapValue, unsafe.Pointer(&key), unsafe.Pointer(&value))
cursor = ctx.skipWhiteSpace()
if buf[cursor] == '}' {
*(*unsafe.Pointer)(unsafe.Pointer(p)) = mapValue
return nil
}
if buf[cursor] != ',' {
return errors.New("unexpected error ,")
}
}
return nil
}