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1// Go support for Protocol Buffers - Google's data interchange format
2//
3// Copyright 2010 The Go Authors.  All rights reserved.
4// https://github.com/golang/protobuf
5//
6// Redistribution and use in source and binary forms, with or without
7// modification, are permitted provided that the following conditions are
8// met:
9//
10//     * Redistributions of source code must retain the above copyright
11// notice, this list of conditions and the following disclaimer.
12//     * Redistributions in binary form must reproduce the above
13// copyright notice, this list of conditions and the following disclaimer
14// in the documentation and/or other materials provided with the
15// distribution.
16//     * Neither the name of Google Inc. nor the names of its
17// contributors may be used to endorse or promote products derived from
18// this software without specific prior written permission.
19//
20// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
24// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
25// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
26// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
30// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31
32package proto
33
34/*
35 * Routines for decoding protocol buffer data to construct in-memory representations.
36 */
37
38import (
39	"errors"
40	"fmt"
41	"io"
42	"os"
43	"reflect"
44)
45
46// errOverflow is returned when an integer is too large to be represented.
47var errOverflow = errors.New("proto: integer overflow")
48
49// ErrInternalBadWireType is returned by generated code when an incorrect
50// wire type is encountered. It does not get returned to user code.
51var ErrInternalBadWireType = errors.New("proto: internal error: bad wiretype for oneof")
52
53// The fundamental decoders that interpret bytes on the wire.
54// Those that take integer types all return uint64 and are
55// therefore of type valueDecoder.
56
57// DecodeVarint reads a varint-encoded integer from the slice.
58// It returns the integer and the number of bytes consumed, or
59// zero if there is not enough.
60// This is the format for the
61// int32, int64, uint32, uint64, bool, and enum
62// protocol buffer types.
63func DecodeVarint(buf []byte) (x uint64, n int) {
64	for shift := uint(0); shift < 64; shift += 7 {
65		if n >= len(buf) {
66			return 0, 0
67		}
68		b := uint64(buf[n])
69		n++
70		x |= (b & 0x7F) << shift
71		if (b & 0x80) == 0 {
72			return x, n
73		}
74	}
75
76	// The number is too large to represent in a 64-bit value.
77	return 0, 0
78}
79
80func (p *Buffer) decodeVarintSlow() (x uint64, err error) {
81	i := p.index
82	l := len(p.buf)
83
84	for shift := uint(0); shift < 64; shift += 7 {
85		if i >= l {
86			err = io.ErrUnexpectedEOF
87			return
88		}
89		b := p.buf[i]
90		i++
91		x |= (uint64(b) & 0x7F) << shift
92		if b < 0x80 {
93			p.index = i
94			return
95		}
96	}
97
98	// The number is too large to represent in a 64-bit value.
99	err = errOverflow
100	return
101}
102
103// DecodeVarint reads a varint-encoded integer from the Buffer.
104// This is the format for the
105// int32, int64, uint32, uint64, bool, and enum
106// protocol buffer types.
107func (p *Buffer) DecodeVarint() (x uint64, err error) {
108	i := p.index
109	buf := p.buf
110
111	if i >= len(buf) {
112		return 0, io.ErrUnexpectedEOF
113	} else if buf[i] < 0x80 {
114		p.index++
115		return uint64(buf[i]), nil
116	} else if len(buf)-i < 10 {
117		return p.decodeVarintSlow()
118	}
119
120	var b uint64
121	// we already checked the first byte
122	x = uint64(buf[i]) - 0x80
123	i++
124
125	b = uint64(buf[i])
126	i++
127	x += b << 7
128	if b&0x80 == 0 {
129		goto done
130	}
131	x -= 0x80 << 7
132
133	b = uint64(buf[i])
134	i++
135	x += b << 14
136	if b&0x80 == 0 {
137		goto done
138	}
139	x -= 0x80 << 14
140
141	b = uint64(buf[i])
142	i++
143	x += b << 21
144	if b&0x80 == 0 {
145		goto done
146	}
147	x -= 0x80 << 21
148
149	b = uint64(buf[i])
150	i++
151	x += b << 28
152	if b&0x80 == 0 {
153		goto done
154	}
155	x -= 0x80 << 28
156
157	b = uint64(buf[i])
158	i++
159	x += b << 35
160	if b&0x80 == 0 {
161		goto done
162	}
163	x -= 0x80 << 35
164
165	b = uint64(buf[i])
166	i++
167	x += b << 42
168	if b&0x80 == 0 {
169		goto done
170	}
171	x -= 0x80 << 42
172
173	b = uint64(buf[i])
174	i++
175	x += b << 49
176	if b&0x80 == 0 {
177		goto done
178	}
179	x -= 0x80 << 49
180
181	b = uint64(buf[i])
182	i++
183	x += b << 56
184	if b&0x80 == 0 {
185		goto done
186	}
187	x -= 0x80 << 56
188
189	b = uint64(buf[i])
190	i++
191	x += b << 63
192	if b&0x80 == 0 {
193		goto done
194	}
195	// x -= 0x80 << 63 // Always zero.
196
197	return 0, errOverflow
198
199done:
200	p.index = i
201	return x, nil
202}
203
204// DecodeFixed64 reads a 64-bit integer from the Buffer.
205// This is the format for the
206// fixed64, sfixed64, and double protocol buffer types.
207func (p *Buffer) DecodeFixed64() (x uint64, err error) {
208	// x, err already 0
209	i := p.index + 8
210	if i < 0 || i > len(p.buf) {
211		err = io.ErrUnexpectedEOF
212		return
213	}
214	p.index = i
215
216	x = uint64(p.buf[i-8])
217	x |= uint64(p.buf[i-7]) << 8
218	x |= uint64(p.buf[i-6]) << 16
219	x |= uint64(p.buf[i-5]) << 24
220	x |= uint64(p.buf[i-4]) << 32
221	x |= uint64(p.buf[i-3]) << 40
222	x |= uint64(p.buf[i-2]) << 48
223	x |= uint64(p.buf[i-1]) << 56
224	return
225}
226
227// DecodeFixed32 reads a 32-bit integer from the Buffer.
228// This is the format for the
229// fixed32, sfixed32, and float protocol buffer types.
230func (p *Buffer) DecodeFixed32() (x uint64, err error) {
231	// x, err already 0
232	i := p.index + 4
233	if i < 0 || i > len(p.buf) {
234		err = io.ErrUnexpectedEOF
235		return
236	}
237	p.index = i
238
239	x = uint64(p.buf[i-4])
240	x |= uint64(p.buf[i-3]) << 8
241	x |= uint64(p.buf[i-2]) << 16
242	x |= uint64(p.buf[i-1]) << 24
243	return
244}
245
246// DecodeZigzag64 reads a zigzag-encoded 64-bit integer
247// from the Buffer.
248// This is the format used for the sint64 protocol buffer type.
249func (p *Buffer) DecodeZigzag64() (x uint64, err error) {
250	x, err = p.DecodeVarint()
251	if err != nil {
252		return
253	}
254	x = (x >> 1) ^ uint64((int64(x&1)<<63)>>63)
255	return
256}
257
258// DecodeZigzag32 reads a zigzag-encoded 32-bit integer
259// from  the Buffer.
260// This is the format used for the sint32 protocol buffer type.
261func (p *Buffer) DecodeZigzag32() (x uint64, err error) {
262	x, err = p.DecodeVarint()
263	if err != nil {
264		return
265	}
266	x = uint64((uint32(x) >> 1) ^ uint32((int32(x&1)<<31)>>31))
267	return
268}
269
270// These are not ValueDecoders: they produce an array of bytes or a string.
271// bytes, embedded messages
272
273// DecodeRawBytes reads a count-delimited byte buffer from the Buffer.
274// This is the format used for the bytes protocol buffer
275// type and for embedded messages.
276func (p *Buffer) DecodeRawBytes(alloc bool) (buf []byte, err error) {
277	n, err := p.DecodeVarint()
278	if err != nil {
279		return nil, err
280	}
281
282	nb := int(n)
283	if nb < 0 {
284		return nil, fmt.Errorf("proto: bad byte length %d", nb)
285	}
286	end := p.index + nb
287	if end < p.index || end > len(p.buf) {
288		return nil, io.ErrUnexpectedEOF
289	}
290
291	if !alloc {
292		// todo: check if can get more uses of alloc=false
293		buf = p.buf[p.index:end]
294		p.index += nb
295		return
296	}
297
298	buf = make([]byte, nb)
299	copy(buf, p.buf[p.index:])
300	p.index += nb
301	return
302}
303
304// DecodeStringBytes reads an encoded string from the Buffer.
305// This is the format used for the proto2 string type.
306func (p *Buffer) DecodeStringBytes() (s string, err error) {
307	buf, err := p.DecodeRawBytes(false)
308	if err != nil {
309		return
310	}
311	return string(buf), nil
312}
313
314// Skip the next item in the buffer. Its wire type is decoded and presented as an argument.
315// If the protocol buffer has extensions, and the field matches, add it as an extension.
316// Otherwise, if the XXX_unrecognized field exists, append the skipped data there.
317func (o *Buffer) skipAndSave(t reflect.Type, tag, wire int, base structPointer, unrecField field) error {
318	oi := o.index
319
320	err := o.skip(t, tag, wire)
321	if err != nil {
322		return err
323	}
324
325	if !unrecField.IsValid() {
326		return nil
327	}
328
329	ptr := structPointer_Bytes(base, unrecField)
330
331	// Add the skipped field to struct field
332	obuf := o.buf
333
334	o.buf = *ptr
335	o.EncodeVarint(uint64(tag<<3 | wire))
336	*ptr = append(o.buf, obuf[oi:o.index]...)
337
338	o.buf = obuf
339
340	return nil
341}
342
343// Skip the next item in the buffer. Its wire type is decoded and presented as an argument.
344func (o *Buffer) skip(t reflect.Type, tag, wire int) error {
345
346	var u uint64
347	var err error
348
349	switch wire {
350	case WireVarint:
351		_, err = o.DecodeVarint()
352	case WireFixed64:
353		_, err = o.DecodeFixed64()
354	case WireBytes:
355		_, err = o.DecodeRawBytes(false)
356	case WireFixed32:
357		_, err = o.DecodeFixed32()
358	case WireStartGroup:
359		for {
360			u, err = o.DecodeVarint()
361			if err != nil {
362				break
363			}
364			fwire := int(u & 0x7)
365			if fwire == WireEndGroup {
366				break
367			}
368			ftag := int(u >> 3)
369			err = o.skip(t, ftag, fwire)
370			if err != nil {
371				break
372			}
373		}
374	default:
375		err = fmt.Errorf("proto: can't skip unknown wire type %d for %s", wire, t)
376	}
377	return err
378}
379
380// Unmarshaler is the interface representing objects that can
381// unmarshal themselves.  The method should reset the receiver before
382// decoding starts.  The argument points to data that may be
383// overwritten, so implementations should not keep references to the
384// buffer.
385type Unmarshaler interface {
386	Unmarshal([]byte) error
387}
388
389// Unmarshal parses the protocol buffer representation in buf and places the
390// decoded result in pb.  If the struct underlying pb does not match
391// the data in buf, the results can be unpredictable.
392//
393// Unmarshal resets pb before starting to unmarshal, so any
394// existing data in pb is always removed. Use UnmarshalMerge
395// to preserve and append to existing data.
396func Unmarshal(buf []byte, pb Message) error {
397	pb.Reset()
398	return UnmarshalMerge(buf, pb)
399}
400
401// UnmarshalMerge parses the protocol buffer representation in buf and
402// writes the decoded result to pb.  If the struct underlying pb does not match
403// the data in buf, the results can be unpredictable.
404//
405// UnmarshalMerge merges into existing data in pb.
406// Most code should use Unmarshal instead.
407func UnmarshalMerge(buf []byte, pb Message) error {
408	// If the object can unmarshal itself, let it.
409	if u, ok := pb.(Unmarshaler); ok {
410		return u.Unmarshal(buf)
411	}
412	return NewBuffer(buf).Unmarshal(pb)
413}
414
415// DecodeMessage reads a count-delimited message from the Buffer.
416func (p *Buffer) DecodeMessage(pb Message) error {
417	enc, err := p.DecodeRawBytes(false)
418	if err != nil {
419		return err
420	}
421	return NewBuffer(enc).Unmarshal(pb)
422}
423
424// DecodeGroup reads a tag-delimited group from the Buffer.
425func (p *Buffer) DecodeGroup(pb Message) error {
426	typ, base, err := getbase(pb)
427	if err != nil {
428		return err
429	}
430	return p.unmarshalType(typ.Elem(), GetProperties(typ.Elem()), true, base)
431}
432
433// Unmarshal parses the protocol buffer representation in the
434// Buffer and places the decoded result in pb.  If the struct
435// underlying pb does not match the data in the buffer, the results can be
436// unpredictable.
437//
438// Unlike proto.Unmarshal, this does not reset pb before starting to unmarshal.
439func (p *Buffer) Unmarshal(pb Message) error {
440	// If the object can unmarshal itself, let it.
441	if u, ok := pb.(Unmarshaler); ok {
442		err := u.Unmarshal(p.buf[p.index:])
443		p.index = len(p.buf)
444		return err
445	}
446
447	typ, base, err := getbase(pb)
448	if err != nil {
449		return err
450	}
451
452	err = p.unmarshalType(typ.Elem(), GetProperties(typ.Elem()), false, base)
453
454	if collectStats {
455		stats.Decode++
456	}
457
458	return err
459}
460
461// unmarshalType does the work of unmarshaling a structure.
462func (o *Buffer) unmarshalType(st reflect.Type, prop *StructProperties, is_group bool, base structPointer) error {
463	var state errorState
464	required, reqFields := prop.reqCount, uint64(0)
465
466	var err error
467	for err == nil && o.index < len(o.buf) {
468		oi := o.index
469		var u uint64
470		u, err = o.DecodeVarint()
471		if err != nil {
472			break
473		}
474		wire := int(u & 0x7)
475		if wire == WireEndGroup {
476			if is_group {
477				if required > 0 {
478					// Not enough information to determine the exact field.
479					// (See below.)
480					return &RequiredNotSetError{"{Unknown}"}
481				}
482				return nil // input is satisfied
483			}
484			return fmt.Errorf("proto: %s: wiretype end group for non-group", st)
485		}
486		tag := int(u >> 3)
487		if tag <= 0 {
488			return fmt.Errorf("proto: %s: illegal tag %d (wire type %d)", st, tag, wire)
489		}
490		fieldnum, ok := prop.decoderTags.get(tag)
491		if !ok {
492			// Maybe it's an extension?
493			if prop.extendable {
494				if e, _ := extendable(structPointer_Interface(base, st)); isExtensionField(e, int32(tag)) {
495					if err = o.skip(st, tag, wire); err == nil {
496						extmap := e.extensionsWrite()
497						ext := extmap[int32(tag)] // may be missing
498						ext.enc = append(ext.enc, o.buf[oi:o.index]...)
499						extmap[int32(tag)] = ext
500					}
501					continue
502				}
503			}
504			// Maybe it's a oneof?
505			if prop.oneofUnmarshaler != nil {
506				m := structPointer_Interface(base, st).(Message)
507				// First return value indicates whether tag is a oneof field.
508				ok, err = prop.oneofUnmarshaler(m, tag, wire, o)
509				if err == ErrInternalBadWireType {
510					// Map the error to something more descriptive.
511					// Do the formatting here to save generated code space.
512					err = fmt.Errorf("bad wiretype for oneof field in %T", m)
513				}
514				if ok {
515					continue
516				}
517			}
518			err = o.skipAndSave(st, tag, wire, base, prop.unrecField)
519			continue
520		}
521		p := prop.Prop[fieldnum]
522
523		if p.dec == nil {
524			fmt.Fprintf(os.Stderr, "proto: no protobuf decoder for %s.%s\n", st, st.Field(fieldnum).Name)
525			continue
526		}
527		dec := p.dec
528		if wire != WireStartGroup && wire != p.WireType {
529			if wire == WireBytes && p.packedDec != nil {
530				// a packable field
531				dec = p.packedDec
532			} else {
533				err = fmt.Errorf("proto: bad wiretype for field %s.%s: got wiretype %d, want %d", st, st.Field(fieldnum).Name, wire, p.WireType)
534				continue
535			}
536		}
537		decErr := dec(o, p, base)
538		if decErr != nil && !state.shouldContinue(decErr, p) {
539			err = decErr
540		}
541		if err == nil && p.Required {
542			// Successfully decoded a required field.
543			if tag <= 64 {
544				// use bitmap for fields 1-64 to catch field reuse.
545				var mask uint64 = 1 << uint64(tag-1)
546				if reqFields&mask == 0 {
547					// new required field
548					reqFields |= mask
549					required--
550				}
551			} else {
552				// This is imprecise. It can be fooled by a required field
553				// with a tag > 64 that is encoded twice; that's very rare.
554				// A fully correct implementation would require allocating
555				// a data structure, which we would like to avoid.
556				required--
557			}
558		}
559	}
560	if err == nil {
561		if is_group {
562			return io.ErrUnexpectedEOF
563		}
564		if state.err != nil {
565			return state.err
566		}
567		if required > 0 {
568			// Not enough information to determine the exact field. If we use extra
569			// CPU, we could determine the field only if the missing required field
570			// has a tag <= 64 and we check reqFields.
571			return &RequiredNotSetError{"{Unknown}"}
572		}
573	}
574	return err
575}
576
577// Individual type decoders
578// For each,
579//	u is the decoded value,
580//	v is a pointer to the field (pointer) in the struct
581
582// Sizes of the pools to allocate inside the Buffer.
583// The goal is modest amortization and allocation
584// on at least 16-byte boundaries.
585const (
586	boolPoolSize   = 16
587	uint32PoolSize = 8
588	uint64PoolSize = 4
589)
590
591// Decode a bool.
592func (o *Buffer) dec_bool(p *Properties, base structPointer) error {
593	u, err := p.valDec(o)
594	if err != nil {
595		return err
596	}
597	if len(o.bools) == 0 {
598		o.bools = make([]bool, boolPoolSize)
599	}
600	o.bools[0] = u != 0
601	*structPointer_Bool(base, p.field) = &o.bools[0]
602	o.bools = o.bools[1:]
603	return nil
604}
605
606func (o *Buffer) dec_proto3_bool(p *Properties, base structPointer) error {
607	u, err := p.valDec(o)
608	if err != nil {
609		return err
610	}
611	*structPointer_BoolVal(base, p.field) = u != 0
612	return nil
613}
614
615// Decode an int32.
616func (o *Buffer) dec_int32(p *Properties, base structPointer) error {
617	u, err := p.valDec(o)
618	if err != nil {
619		return err
620	}
621	word32_Set(structPointer_Word32(base, p.field), o, uint32(u))
622	return nil
623}
624
625func (o *Buffer) dec_proto3_int32(p *Properties, base structPointer) error {
626	u, err := p.valDec(o)
627	if err != nil {
628		return err
629	}
630	word32Val_Set(structPointer_Word32Val(base, p.field), uint32(u))
631	return nil
632}
633
634// Decode an int64.
635func (o *Buffer) dec_int64(p *Properties, base structPointer) error {
636	u, err := p.valDec(o)
637	if err != nil {
638		return err
639	}
640	word64_Set(structPointer_Word64(base, p.field), o, u)
641	return nil
642}
643
644func (o *Buffer) dec_proto3_int64(p *Properties, base structPointer) error {
645	u, err := p.valDec(o)
646	if err != nil {
647		return err
648	}
649	word64Val_Set(structPointer_Word64Val(base, p.field), o, u)
650	return nil
651}
652
653// Decode a string.
654func (o *Buffer) dec_string(p *Properties, base structPointer) error {
655	s, err := o.DecodeStringBytes()
656	if err != nil {
657		return err
658	}
659	*structPointer_String(base, p.field) = &s
660	return nil
661}
662
663func (o *Buffer) dec_proto3_string(p *Properties, base structPointer) error {
664	s, err := o.DecodeStringBytes()
665	if err != nil {
666		return err
667	}
668	*structPointer_StringVal(base, p.field) = s
669	return nil
670}
671
672// Decode a slice of bytes ([]byte).
673func (o *Buffer) dec_slice_byte(p *Properties, base structPointer) error {
674	b, err := o.DecodeRawBytes(true)
675	if err != nil {
676		return err
677	}
678	*structPointer_Bytes(base, p.field) = b
679	return nil
680}
681
682// Decode a slice of bools ([]bool).
683func (o *Buffer) dec_slice_bool(p *Properties, base structPointer) error {
684	u, err := p.valDec(o)
685	if err != nil {
686		return err
687	}
688	v := structPointer_BoolSlice(base, p.field)
689	*v = append(*v, u != 0)
690	return nil
691}
692
693// Decode a slice of bools ([]bool) in packed format.
694func (o *Buffer) dec_slice_packed_bool(p *Properties, base structPointer) error {
695	v := structPointer_BoolSlice(base, p.field)
696
697	nn, err := o.DecodeVarint()
698	if err != nil {
699		return err
700	}
701	nb := int(nn) // number of bytes of encoded bools
702	fin := o.index + nb
703	if fin < o.index {
704		return errOverflow
705	}
706
707	y := *v
708	for o.index < fin {
709		u, err := p.valDec(o)
710		if err != nil {
711			return err
712		}
713		y = append(y, u != 0)
714	}
715
716	*v = y
717	return nil
718}
719
720// Decode a slice of int32s ([]int32).
721func (o *Buffer) dec_slice_int32(p *Properties, base structPointer) error {
722	u, err := p.valDec(o)
723	if err != nil {
724		return err
725	}
726	structPointer_Word32Slice(base, p.field).Append(uint32(u))
727	return nil
728}
729
730// Decode a slice of int32s ([]int32) in packed format.
731func (o *Buffer) dec_slice_packed_int32(p *Properties, base structPointer) error {
732	v := structPointer_Word32Slice(base, p.field)
733
734	nn, err := o.DecodeVarint()
735	if err != nil {
736		return err
737	}
738	nb := int(nn) // number of bytes of encoded int32s
739
740	fin := o.index + nb
741	if fin < o.index {
742		return errOverflow
743	}
744	for o.index < fin {
745		u, err := p.valDec(o)
746		if err != nil {
747			return err
748		}
749		v.Append(uint32(u))
750	}
751	return nil
752}
753
754// Decode a slice of int64s ([]int64).
755func (o *Buffer) dec_slice_int64(p *Properties, base structPointer) error {
756	u, err := p.valDec(o)
757	if err != nil {
758		return err
759	}
760
761	structPointer_Word64Slice(base, p.field).Append(u)
762	return nil
763}
764
765// Decode a slice of int64s ([]int64) in packed format.
766func (o *Buffer) dec_slice_packed_int64(p *Properties, base structPointer) error {
767	v := structPointer_Word64Slice(base, p.field)
768
769	nn, err := o.DecodeVarint()
770	if err != nil {
771		return err
772	}
773	nb := int(nn) // number of bytes of encoded int64s
774
775	fin := o.index + nb
776	if fin < o.index {
777		return errOverflow
778	}
779	for o.index < fin {
780		u, err := p.valDec(o)
781		if err != nil {
782			return err
783		}
784		v.Append(u)
785	}
786	return nil
787}
788
789// Decode a slice of strings ([]string).
790func (o *Buffer) dec_slice_string(p *Properties, base structPointer) error {
791	s, err := o.DecodeStringBytes()
792	if err != nil {
793		return err
794	}
795	v := structPointer_StringSlice(base, p.field)
796	*v = append(*v, s)
797	return nil
798}
799
800// Decode a slice of slice of bytes ([][]byte).
801func (o *Buffer) dec_slice_slice_byte(p *Properties, base structPointer) error {
802	b, err := o.DecodeRawBytes(true)
803	if err != nil {
804		return err
805	}
806	v := structPointer_BytesSlice(base, p.field)
807	*v = append(*v, b)
808	return nil
809}
810
811// Decode a map field.
812func (o *Buffer) dec_new_map(p *Properties, base structPointer) error {
813	raw, err := o.DecodeRawBytes(false)
814	if err != nil {
815		return err
816	}
817	oi := o.index       // index at the end of this map entry
818	o.index -= len(raw) // move buffer back to start of map entry
819
820	mptr := structPointer_NewAt(base, p.field, p.mtype) // *map[K]V
821	if mptr.Elem().IsNil() {
822		mptr.Elem().Set(reflect.MakeMap(mptr.Type().Elem()))
823	}
824	v := mptr.Elem() // map[K]V
825
826	// Prepare addressable doubly-indirect placeholders for the key and value types.
827	// See enc_new_map for why.
828	keyptr := reflect.New(reflect.PtrTo(p.mtype.Key())).Elem() // addressable *K
829	keybase := toStructPointer(keyptr.Addr())                  // **K
830
831	var valbase structPointer
832	var valptr reflect.Value
833	switch p.mtype.Elem().Kind() {
834	case reflect.Slice:
835		// []byte
836		var dummy []byte
837		valptr = reflect.ValueOf(&dummy)  // *[]byte
838		valbase = toStructPointer(valptr) // *[]byte
839	case reflect.Ptr:
840		// message; valptr is **Msg; need to allocate the intermediate pointer
841		valptr = reflect.New(reflect.PtrTo(p.mtype.Elem())).Elem() // addressable *V
842		valptr.Set(reflect.New(valptr.Type().Elem()))
843		valbase = toStructPointer(valptr)
844	default:
845		// everything else
846		valptr = reflect.New(reflect.PtrTo(p.mtype.Elem())).Elem() // addressable *V
847		valbase = toStructPointer(valptr.Addr())                   // **V
848	}
849
850	// Decode.
851	// This parses a restricted wire format, namely the encoding of a message
852	// with two fields. See enc_new_map for the format.
853	for o.index < oi {
854		// tagcode for key and value properties are always a single byte
855		// because they have tags 1 and 2.
856		tagcode := o.buf[o.index]
857		o.index++
858		switch tagcode {
859		case p.mkeyprop.tagcode[0]:
860			if err := p.mkeyprop.dec(o, p.mkeyprop, keybase); err != nil {
861				return err
862			}
863		case p.mvalprop.tagcode[0]:
864			if err := p.mvalprop.dec(o, p.mvalprop, valbase); err != nil {
865				return err
866			}
867		default:
868			// TODO: Should we silently skip this instead?
869			return fmt.Errorf("proto: bad map data tag %d", raw[0])
870		}
871	}
872	keyelem, valelem := keyptr.Elem(), valptr.Elem()
873	if !keyelem.IsValid() {
874		keyelem = reflect.Zero(p.mtype.Key())
875	}
876	if !valelem.IsValid() {
877		valelem = reflect.Zero(p.mtype.Elem())
878	}
879
880	v.SetMapIndex(keyelem, valelem)
881	return nil
882}
883
884// Decode a group.
885func (o *Buffer) dec_struct_group(p *Properties, base structPointer) error {
886	bas := structPointer_GetStructPointer(base, p.field)
887	if structPointer_IsNil(bas) {
888		// allocate new nested message
889		bas = toStructPointer(reflect.New(p.stype))
890		structPointer_SetStructPointer(base, p.field, bas)
891	}
892	return o.unmarshalType(p.stype, p.sprop, true, bas)
893}
894
895// Decode an embedded message.
896func (o *Buffer) dec_struct_message(p *Properties, base structPointer) (err error) {
897	raw, e := o.DecodeRawBytes(false)
898	if e != nil {
899		return e
900	}
901
902	bas := structPointer_GetStructPointer(base, p.field)
903	if structPointer_IsNil(bas) {
904		// allocate new nested message
905		bas = toStructPointer(reflect.New(p.stype))
906		structPointer_SetStructPointer(base, p.field, bas)
907	}
908
909	// If the object can unmarshal itself, let it.
910	if p.isUnmarshaler {
911		iv := structPointer_Interface(bas, p.stype)
912		return iv.(Unmarshaler).Unmarshal(raw)
913	}
914
915	obuf := o.buf
916	oi := o.index
917	o.buf = raw
918	o.index = 0
919
920	err = o.unmarshalType(p.stype, p.sprop, false, bas)
921	o.buf = obuf
922	o.index = oi
923
924	return err
925}
926
927// Decode a slice of embedded messages.
928func (o *Buffer) dec_slice_struct_message(p *Properties, base structPointer) error {
929	return o.dec_slice_struct(p, false, base)
930}
931
932// Decode a slice of embedded groups.
933func (o *Buffer) dec_slice_struct_group(p *Properties, base structPointer) error {
934	return o.dec_slice_struct(p, true, base)
935}
936
937// Decode a slice of structs ([]*struct).
938func (o *Buffer) dec_slice_struct(p *Properties, is_group bool, base structPointer) error {
939	v := reflect.New(p.stype)
940	bas := toStructPointer(v)
941	structPointer_StructPointerSlice(base, p.field).Append(bas)
942
943	if is_group {
944		err := o.unmarshalType(p.stype, p.sprop, is_group, bas)
945		return err
946	}
947
948	raw, err := o.DecodeRawBytes(false)
949	if err != nil {
950		return err
951	}
952
953	// If the object can unmarshal itself, let it.
954	if p.isUnmarshaler {
955		iv := v.Interface()
956		return iv.(Unmarshaler).Unmarshal(raw)
957	}
958
959	obuf := o.buf
960	oi := o.index
961	o.buf = raw
962	o.index = 0
963
964	err = o.unmarshalType(p.stype, p.sprop, is_group, bas)
965
966	o.buf = obuf
967	o.index = oi
968
969	return err
970}
971