forked from mirror/go-json
74 lines
1.6 KiB
Go
74 lines
1.6 KiB
Go
package json
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import (
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"errors"
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"reflect"
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"unsafe"
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)
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type sliceDecoder struct {
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elemType *rtype
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valueDecoder decoder
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size uintptr
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}
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func newSliceDecoder(dec decoder, elemType *rtype, size uintptr) *sliceDecoder {
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return &sliceDecoder{
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valueDecoder: dec,
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elemType: elemType,
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size: size,
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}
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}
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//go:linkname copySlice reflect.typedslicecopy
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func copySlice(elemType *rtype, dst, src reflect.SliceHeader) int
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//go:linkname newArray reflect.unsafe_NewArray
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func newArray(*rtype, int) unsafe.Pointer
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func (d *sliceDecoder) decode(ctx *context, p uintptr) error {
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buf := ctx.buf
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buflen := ctx.buflen
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cursor := ctx.cursor
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for ; cursor < buflen; cursor++ {
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switch buf[cursor] {
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case ' ', '\n', '\t', '\r':
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continue
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case '[':
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idx := 0
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cap := 2
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data := uintptr(newArray(d.elemType, cap))
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for {
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ctx.cursor = cursor + 1
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if cap <= idx {
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src := reflect.SliceHeader{Data: data, Len: idx, Cap: cap}
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cap *= 2
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data = uintptr(newArray(d.elemType, cap))
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dst := reflect.SliceHeader{Data: data, Len: idx, Cap: cap}
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copySlice(d.elemType, dst, src)
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}
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if err := d.valueDecoder.decode(ctx, data+uintptr(idx)*d.size); err != nil {
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return err
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}
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cursor = ctx.skipWhiteSpace()
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switch buf[cursor] {
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case ']':
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*(*reflect.SliceHeader)(unsafe.Pointer(p)) = reflect.SliceHeader{
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Data: data,
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Len: idx + 1,
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Cap: cap,
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}
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ctx.cursor++
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return nil
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case ',':
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idx++
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continue
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default:
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return errors.New("syntax error slice")
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}
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}
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}
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}
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return errors.New("unexpected error slice")
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}
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