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package proto
import (
"io"
"reflect"
"unsafe"
. "github.com/segmentio/encoding/internal/runtime_reflect"
)
type repeatedField struct {
codec *codec
fieldNumber fieldNumber
wireType wireType
embedded bool
}
func sliceCodecOf(t reflect.Type, f structField, seen map[reflect.Type]*codec) *codec {
s := new(codec)
seen[t] = s
r := &repeatedField{
codec: f.codec,
fieldNumber: f.fieldNumber(),
wireType: f.wireType(),
embedded: f.embedded(),
}
s.wire = f.codec.wire
s.size = sliceSizeFuncOf(t, r)
s.encode = sliceEncodeFuncOf(t, r)
s.decode = sliceDecodeFuncOf(t, r)
return s
}
func sliceSizeFuncOf(t reflect.Type, r *repeatedField) sizeFunc {
elemSize := alignedSize(t.Elem())
tagSize := sizeOfTag(r.fieldNumber, r.wireType)
return func(p unsafe.Pointer, _ flags) int {
n := 0
if v := (*Slice)(p); v != nil {
for i := range v.Len() {
elem := v.Index(i, elemSize)
size := r.codec.size(elem, wantzero)
n += tagSize + size
if r.embedded {
n += sizeOfVarint(uint64(size))
}
}
}
return n
}
}
func sliceEncodeFuncOf(t reflect.Type, r *repeatedField) encodeFunc {
elemSize := alignedSize(t.Elem())
tagSize := sizeOfTag(r.fieldNumber, r.wireType)
tagData := make([]byte, tagSize)
encodeTag(tagData, r.fieldNumber, r.wireType)
return func(b []byte, p unsafe.Pointer, _ flags) (int, error) {
offset := 0
if s := (*Slice)(p); s != nil {
for i := range s.Len() {
elem := s.Index(i, elemSize)
size := r.codec.size(elem, wantzero)
n := copy(b[offset:], tagData)
offset += n
if n < len(tagData) {
return offset, io.ErrShortBuffer
}
if r.embedded {
n, err := encodeVarint(b[offset:], uint64(size))
offset += n
if err != nil {
return offset, err
}
}
if (len(b) - offset) < size {
return len(b), io.ErrShortBuffer
}
n, err := r.codec.encode(b[offset:offset+size], elem, wantzero)
offset += n
if err != nil {
return offset, err
}
}
}
return offset, nil
}
}
func sliceDecodeFuncOf(t reflect.Type, r *repeatedField) decodeFunc {
elemType := t.Elem()
elemSize := alignedSize(elemType)
return func(b []byte, p unsafe.Pointer, _ flags) (int, error) {
s := (*Slice)(p)
i := s.Len()
if i == s.Cap() {
*s = growSlice(elemType, s)
}
n, err := r.codec.decode(b, s.Index(i, elemSize), noflags)
if err == nil {
s.SetLen(i + 1)
}
return n, err
}
}
func alignedSize(t reflect.Type) uintptr {
a := t.Align()
s := t.Size()
return align(uintptr(a), uintptr(s))
}
func align(align, size uintptr) uintptr {
if align != 0 && (size%align) != 0 {
size = ((size / align) + 1) * align
}
return size
}
func growSlice(t reflect.Type, s *Slice) Slice {
cap := 2 * s.Cap()
if cap == 0 {
cap = 10
}
p := pointer(t)
d := MakeSlice(p, s.Len(), cap)
CopySlice(p, d, *s)
return d
}
|
