1 // Protocol Buffers - Google's data interchange format
2 // Copyright 2008 Google Inc. All rights reserved.
3 // https://developers.google.com/protocol-buffers/
4 //
5 // Redistribution and use in source and binary forms, with or without
6 // modification, are permitted provided that the following conditions are
7 // met:
8 //
9 // * Redistributions of source code must retain the above copyright
10 // notice, this list of conditions and the following disclaimer.
11 // * Redistributions in binary form must reproduce the above
12 // copyright notice, this list of conditions and the following disclaimer
13 // in the documentation and/or other materials provided with the
14 // distribution.
15 // * Neither the name of Google Inc. nor the names of its
16 // contributors may be used to endorse or promote products derived from
17 // this software without specific prior written permission.
18 //
19 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30
31 // Author: kenton@google.com (Kenton Varda)
32 // atenasio@google.com (Chris Atenasio) (ZigZag transform)
33 // wink@google.com (Wink Saville) (refactored from wire_format.h)
34 // Based on original Protocol Buffers design by
35 // Sanjay Ghemawat, Jeff Dean, and others.
36 //
37 // This header is logically internal, but is made public because it is used
38 // from protocol-compiler-generated code, which may reside in other components.
39
40 #ifndef GOOGLE_PROTOBUF_WIRE_FORMAT_LITE_H__
41 #define GOOGLE_PROTOBUF_WIRE_FORMAT_LITE_H__
42
43 #include <string>
44 #include <google/protobuf/stubs/common.h>
45 #include <google/protobuf/message_lite.h>
46 #include <google/protobuf/io/coded_stream.h> // for CodedOutputStream::Varint32Size
47
48 namespace google {
49
50 namespace protobuf {
51 template <typename T> class RepeatedField; // repeated_field.h
52 }
53
54 namespace protobuf {
55 namespace internal {
56
57 class StringPieceField;
58
59 // This class is for internal use by the protocol buffer library and by
60 // protocol-complier-generated message classes. It must not be called
61 // directly by clients.
62 //
63 // This class contains helpers for implementing the binary protocol buffer
64 // wire format without the need for reflection. Use WireFormat when using
65 // reflection.
66 //
67 // This class is really a namespace that contains only static methods.
68 class LIBPROTOBUF_EXPORT WireFormatLite {
69 public:
70
71 // -----------------------------------------------------------------
72 // Helper constants and functions related to the format. These are
73 // mostly meant for internal and generated code to use.
74
75 // The wire format is composed of a sequence of tag/value pairs, each
76 // of which contains the value of one field (or one element of a repeated
77 // field). Each tag is encoded as a varint. The lower bits of the tag
78 // identify its wire type, which specifies the format of the data to follow.
79 // The rest of the bits contain the field number. Each type of field (as
80 // declared by FieldDescriptor::Type, in descriptor.h) maps to one of
81 // these wire types. Immediately following each tag is the field's value,
82 // encoded in the format specified by the wire type. Because the tag
83 // identifies the encoding of this data, it is possible to skip
84 // unrecognized fields for forwards compatibility.
85
86 enum WireType {
87 WIRETYPE_VARINT = 0,
88 WIRETYPE_FIXED64 = 1,
89 WIRETYPE_LENGTH_DELIMITED = 2,
90 WIRETYPE_START_GROUP = 3,
91 WIRETYPE_END_GROUP = 4,
92 WIRETYPE_FIXED32 = 5,
93 };
94
95 // Lite alternative to FieldDescriptor::Type. Must be kept in sync.
96 enum FieldType {
97 TYPE_DOUBLE = 1,
98 TYPE_FLOAT = 2,
99 TYPE_INT64 = 3,
100 TYPE_UINT64 = 4,
101 TYPE_INT32 = 5,
102 TYPE_FIXED64 = 6,
103 TYPE_FIXED32 = 7,
104 TYPE_BOOL = 8,
105 TYPE_STRING = 9,
106 TYPE_GROUP = 10,
107 TYPE_MESSAGE = 11,
108 TYPE_BYTES = 12,
109 TYPE_UINT32 = 13,
110 TYPE_ENUM = 14,
111 TYPE_SFIXED32 = 15,
112 TYPE_SFIXED64 = 16,
113 TYPE_SINT32 = 17,
114 TYPE_SINT64 = 18,
115 MAX_FIELD_TYPE = 18,
116 };
117
118 // Lite alternative to FieldDescriptor::CppType. Must be kept in sync.
119 enum CppType {
120 CPPTYPE_INT32 = 1,
121 CPPTYPE_INT64 = 2,
122 CPPTYPE_UINT32 = 3,
123 CPPTYPE_UINT64 = 4,
124 CPPTYPE_DOUBLE = 5,
125 CPPTYPE_FLOAT = 6,
126 CPPTYPE_BOOL = 7,
127 CPPTYPE_ENUM = 8,
128 CPPTYPE_STRING = 9,
129 CPPTYPE_MESSAGE = 10,
130 MAX_CPPTYPE = 10,
131 };
132
133 // Helper method to get the CppType for a particular Type.
134 static CppType FieldTypeToCppType(FieldType type);
135
136 // Given a FieldSescriptor::Type return its WireType
WireTypeForFieldType(WireFormatLite::FieldType type)137 static inline WireFormatLite::WireType WireTypeForFieldType(
138 WireFormatLite::FieldType type) {
139 return kWireTypeForFieldType[type];
140 }
141
142 // Number of bits in a tag which identify the wire type.
143 static const int kTagTypeBits = 3;
144 // Mask for those bits.
145 static const uint32 kTagTypeMask = (1 << kTagTypeBits) - 1;
146
147 // Helper functions for encoding and decoding tags. (Inlined below and in
148 // _inl.h)
149 //
150 // This is different from MakeTag(field->number(), field->type()) in the case
151 // of packed repeated fields.
152 static uint32 MakeTag(int field_number, WireType type);
153 static WireType GetTagWireType(uint32 tag);
154 static int GetTagFieldNumber(uint32 tag);
155
156 // Compute the byte size of a tag. For groups, this includes both the start
157 // and end tags.
158 static inline int TagSize(int field_number, WireFormatLite::FieldType type);
159
160 // Skips a field value with the given tag. The input should start
161 // positioned immediately after the tag. Skipped values are simply discarded,
162 // not recorded anywhere. See WireFormat::SkipField() for a version that
163 // records to an UnknownFieldSet.
164 static bool SkipField(io::CodedInputStream* input, uint32 tag);
165
166 // Skips a field value with the given tag. The input should start
167 // positioned immediately after the tag. Skipped values are recorded to a
168 // CodedOutputStream.
169 static bool SkipField(io::CodedInputStream* input, uint32 tag,
170 io::CodedOutputStream* output);
171
172 // Reads and ignores a message from the input. Skipped values are simply
173 // discarded, not recorded anywhere. See WireFormat::SkipMessage() for a
174 // version that records to an UnknownFieldSet.
175 static bool SkipMessage(io::CodedInputStream* input);
176
177 // Reads and ignores a message from the input. Skipped values are recorded
178 // to a CodedOutputStream.
179 static bool SkipMessage(io::CodedInputStream* input,
180 io::CodedOutputStream* output);
181
182 // This macro does the same thing as WireFormatLite::MakeTag(), but the
183 // result is usable as a compile-time constant, which makes it usable
184 // as a switch case or a template input. WireFormatLite::MakeTag() is more
185 // type-safe, though, so prefer it if possible.
186 #define GOOGLE_PROTOBUF_WIRE_FORMAT_MAKE_TAG(FIELD_NUMBER, TYPE) \
187 static_cast<uint32>( \
188 ((FIELD_NUMBER) << ::google::protobuf::internal::WireFormatLite::kTagTypeBits) \
189 | (TYPE))
190
191 // These are the tags for the old MessageSet format, which was defined as:
192 // message MessageSet {
193 // repeated group Item = 1 {
194 // required int32 type_id = 2;
195 // required string message = 3;
196 // }
197 // }
198 static const int kMessageSetItemNumber = 1;
199 static const int kMessageSetTypeIdNumber = 2;
200 static const int kMessageSetMessageNumber = 3;
201 static const int kMessageSetItemStartTag =
202 GOOGLE_PROTOBUF_WIRE_FORMAT_MAKE_TAG(kMessageSetItemNumber,
203 WireFormatLite::WIRETYPE_START_GROUP);
204 static const int kMessageSetItemEndTag =
205 GOOGLE_PROTOBUF_WIRE_FORMAT_MAKE_TAG(kMessageSetItemNumber,
206 WireFormatLite::WIRETYPE_END_GROUP);
207 static const int kMessageSetTypeIdTag =
208 GOOGLE_PROTOBUF_WIRE_FORMAT_MAKE_TAG(kMessageSetTypeIdNumber,
209 WireFormatLite::WIRETYPE_VARINT);
210 static const int kMessageSetMessageTag =
211 GOOGLE_PROTOBUF_WIRE_FORMAT_MAKE_TAG(kMessageSetMessageNumber,
212 WireFormatLite::WIRETYPE_LENGTH_DELIMITED);
213
214 // Byte size of all tags of a MessageSet::Item combined.
215 static const int kMessageSetItemTagsSize;
216
217 // Helper functions for converting between floats/doubles and IEEE-754
218 // uint32s/uint64s so that they can be written. (Assumes your platform
219 // uses IEEE-754 floats.)
220 static uint32 EncodeFloat(float value);
221 static float DecodeFloat(uint32 value);
222 static uint64 EncodeDouble(double value);
223 static double DecodeDouble(uint64 value);
224
225 // Helper functions for mapping signed integers to unsigned integers in
226 // such a way that numbers with small magnitudes will encode to smaller
227 // varints. If you simply static_cast a negative number to an unsigned
228 // number and varint-encode it, it will always take 10 bytes, defeating
229 // the purpose of varint. So, for the "sint32" and "sint64" field types,
230 // we ZigZag-encode the values.
231 static uint32 ZigZagEncode32(int32 n);
232 static int32 ZigZagDecode32(uint32 n);
233 static uint64 ZigZagEncode64(int64 n);
234 static int64 ZigZagDecode64(uint64 n);
235
236 // =================================================================
237 // Methods for reading/writing individual field. The implementations
238 // of these methods are defined in wire_format_lite_inl.h; you must #include
239 // that file to use these.
240
241 // Avoid ugly line wrapping
242 #define input io::CodedInputStream* input_arg
243 #define output io::CodedOutputStream* output_arg
244 #define field_number int field_number_arg
245 #define INL GOOGLE_ATTRIBUTE_ALWAYS_INLINE
246
247 // Read fields, not including tags. The assumption is that you already
248 // read the tag to determine what field to read.
249
250 // For primitive fields, we just use a templatized routine parameterized by
251 // the represented type and the FieldType. These are specialized with the
252 // appropriate definition for each declared type.
253 template <typename CType, enum FieldType DeclaredType>
254 static inline bool ReadPrimitive(input, CType* value) INL;
255
256 // Reads repeated primitive values, with optimizations for repeats.
257 // tag_size and tag should both be compile-time constants provided by the
258 // protocol compiler.
259 template <typename CType, enum FieldType DeclaredType>
260 static inline bool ReadRepeatedPrimitive(int tag_size,
261 uint32 tag,
262 input,
263 RepeatedField<CType>* value) INL;
264
265 // Identical to ReadRepeatedPrimitive, except will not inline the
266 // implementation.
267 template <typename CType, enum FieldType DeclaredType>
268 static bool ReadRepeatedPrimitiveNoInline(int tag_size,
269 uint32 tag,
270 input,
271 RepeatedField<CType>* value);
272
273 // Reads a primitive value directly from the provided buffer. It returns a
274 // pointer past the segment of data that was read.
275 //
276 // This is only implemented for the types with fixed wire size, e.g.
277 // float, double, and the (s)fixed* types.
278 template <typename CType, enum FieldType DeclaredType>
279 static inline const uint8* ReadPrimitiveFromArray(const uint8* buffer,
280 CType* value) INL;
281
282 // Reads a primitive packed field.
283 //
284 // This is only implemented for packable types.
285 template <typename CType, enum FieldType DeclaredType>
286 static inline bool ReadPackedPrimitive(input,
287 RepeatedField<CType>* value) INL;
288
289 // Identical to ReadPackedPrimitive, except will not inline the
290 // implementation.
291 template <typename CType, enum FieldType DeclaredType>
292 static bool ReadPackedPrimitiveNoInline(input, RepeatedField<CType>* value);
293
294 // Read a packed enum field. Values for which is_valid() returns false are
295 // dropped.
296 static bool ReadPackedEnumNoInline(input,
297 bool (*is_valid)(int),
298 RepeatedField<int>* value);
299
300 static bool ReadString(input, string* value);
301 static bool ReadBytes (input, string* value);
302
303 static inline bool ReadGroup (field_number, input, MessageLite* value);
304 static inline bool ReadMessage(input, MessageLite* value);
305
306 // Like above, but de-virtualize the call to MergePartialFromCodedStream().
307 // The pointer must point at an instance of MessageType, *not* a subclass (or
308 // the subclass must not override MergePartialFromCodedStream()).
309 template<typename MessageType>
310 static inline bool ReadGroupNoVirtual(field_number, input,
311 MessageType* value);
312 template<typename MessageType>
313 static inline bool ReadMessageNoVirtual(input, MessageType* value);
314
315 // Write a tag. The Write*() functions typically include the tag, so
316 // normally there's no need to call this unless using the Write*NoTag()
317 // variants.
318 static inline void WriteTag(field_number, WireType type, output) INL;
319
320 // Write fields, without tags.
321 static inline void WriteInt32NoTag (int32 value, output) INL;
322 static inline void WriteInt64NoTag (int64 value, output) INL;
323 static inline void WriteUInt32NoTag (uint32 value, output) INL;
324 static inline void WriteUInt64NoTag (uint64 value, output) INL;
325 static inline void WriteSInt32NoTag (int32 value, output) INL;
326 static inline void WriteSInt64NoTag (int64 value, output) INL;
327 static inline void WriteFixed32NoTag (uint32 value, output) INL;
328 static inline void WriteFixed64NoTag (uint64 value, output) INL;
329 static inline void WriteSFixed32NoTag(int32 value, output) INL;
330 static inline void WriteSFixed64NoTag(int64 value, output) INL;
331 static inline void WriteFloatNoTag (float value, output) INL;
332 static inline void WriteDoubleNoTag (double value, output) INL;
333 static inline void WriteBoolNoTag (bool value, output) INL;
334 static inline void WriteEnumNoTag (int value, output) INL;
335
336 // Write fields, including tags.
337 static void WriteInt32 (field_number, int32 value, output);
338 static void WriteInt64 (field_number, int64 value, output);
339 static void WriteUInt32 (field_number, uint32 value, output);
340 static void WriteUInt64 (field_number, uint64 value, output);
341 static void WriteSInt32 (field_number, int32 value, output);
342 static void WriteSInt64 (field_number, int64 value, output);
343 static void WriteFixed32 (field_number, uint32 value, output);
344 static void WriteFixed64 (field_number, uint64 value, output);
345 static void WriteSFixed32(field_number, int32 value, output);
346 static void WriteSFixed64(field_number, int64 value, output);
347 static void WriteFloat (field_number, float value, output);
348 static void WriteDouble (field_number, double value, output);
349 static void WriteBool (field_number, bool value, output);
350 static void WriteEnum (field_number, int value, output);
351
352 static void WriteString(field_number, const string& value, output);
353 static void WriteBytes (field_number, const string& value, output);
354 static void WriteStringMaybeAliased(
355 field_number, const string& value, output);
356 static void WriteBytesMaybeAliased(
357 field_number, const string& value, output);
358
359 static void WriteGroup(
360 field_number, const MessageLite& value, output);
361 static void WriteMessage(
362 field_number, const MessageLite& value, output);
363 // Like above, but these will check if the output stream has enough
364 // space to write directly to a flat array.
365 static void WriteGroupMaybeToArray(
366 field_number, const MessageLite& value, output);
367 static void WriteMessageMaybeToArray(
368 field_number, const MessageLite& value, output);
369
370 // Like above, but de-virtualize the call to SerializeWithCachedSizes(). The
371 // pointer must point at an instance of MessageType, *not* a subclass (or
372 // the subclass must not override SerializeWithCachedSizes()).
373 template<typename MessageType>
374 static inline void WriteGroupNoVirtual(
375 field_number, const MessageType& value, output);
376 template<typename MessageType>
377 static inline void WriteMessageNoVirtual(
378 field_number, const MessageType& value, output);
379
380 #undef output
381 #define output uint8* target
382
383 // Like above, but use only *ToArray methods of CodedOutputStream.
384 static inline uint8* WriteTagToArray(field_number, WireType type, output) INL;
385
386 // Write fields, without tags.
387 static inline uint8* WriteInt32NoTagToArray (int32 value, output) INL;
388 static inline uint8* WriteInt64NoTagToArray (int64 value, output) INL;
389 static inline uint8* WriteUInt32NoTagToArray (uint32 value, output) INL;
390 static inline uint8* WriteUInt64NoTagToArray (uint64 value, output) INL;
391 static inline uint8* WriteSInt32NoTagToArray (int32 value, output) INL;
392 static inline uint8* WriteSInt64NoTagToArray (int64 value, output) INL;
393 static inline uint8* WriteFixed32NoTagToArray (uint32 value, output) INL;
394 static inline uint8* WriteFixed64NoTagToArray (uint64 value, output) INL;
395 static inline uint8* WriteSFixed32NoTagToArray(int32 value, output) INL;
396 static inline uint8* WriteSFixed64NoTagToArray(int64 value, output) INL;
397 static inline uint8* WriteFloatNoTagToArray (float value, output) INL;
398 static inline uint8* WriteDoubleNoTagToArray (double value, output) INL;
399 static inline uint8* WriteBoolNoTagToArray (bool value, output) INL;
400 static inline uint8* WriteEnumNoTagToArray (int value, output) INL;
401
402 // Write fields, including tags.
403 static inline uint8* WriteInt32ToArray(
404 field_number, int32 value, output) INL;
405 static inline uint8* WriteInt64ToArray(
406 field_number, int64 value, output) INL;
407 static inline uint8* WriteUInt32ToArray(
408 field_number, uint32 value, output) INL;
409 static inline uint8* WriteUInt64ToArray(
410 field_number, uint64 value, output) INL;
411 static inline uint8* WriteSInt32ToArray(
412 field_number, int32 value, output) INL;
413 static inline uint8* WriteSInt64ToArray(
414 field_number, int64 value, output) INL;
415 static inline uint8* WriteFixed32ToArray(
416 field_number, uint32 value, output) INL;
417 static inline uint8* WriteFixed64ToArray(
418 field_number, uint64 value, output) INL;
419 static inline uint8* WriteSFixed32ToArray(
420 field_number, int32 value, output) INL;
421 static inline uint8* WriteSFixed64ToArray(
422 field_number, int64 value, output) INL;
423 static inline uint8* WriteFloatToArray(
424 field_number, float value, output) INL;
425 static inline uint8* WriteDoubleToArray(
426 field_number, double value, output) INL;
427 static inline uint8* WriteBoolToArray(
428 field_number, bool value, output) INL;
429 static inline uint8* WriteEnumToArray(
430 field_number, int value, output) INL;
431
432 static inline uint8* WriteStringToArray(
433 field_number, const string& value, output) INL;
434 static inline uint8* WriteBytesToArray(
435 field_number, const string& value, output) INL;
436
437 static inline uint8* WriteGroupToArray(
438 field_number, const MessageLite& value, output) INL;
439 static inline uint8* WriteMessageToArray(
440 field_number, const MessageLite& value, output) INL;
441
442 // Like above, but de-virtualize the call to SerializeWithCachedSizes(). The
443 // pointer must point at an instance of MessageType, *not* a subclass (or
444 // the subclass must not override SerializeWithCachedSizes()).
445 template<typename MessageType>
446 static inline uint8* WriteGroupNoVirtualToArray(
447 field_number, const MessageType& value, output) INL;
448 template<typename MessageType>
449 static inline uint8* WriteMessageNoVirtualToArray(
450 field_number, const MessageType& value, output) INL;
451
452 #undef output
453 #undef input
454 #undef INL
455
456 #undef field_number
457
458 // Compute the byte size of a field. The XxSize() functions do NOT include
459 // the tag, so you must also call TagSize(). (This is because, for repeated
460 // fields, you should only call TagSize() once and multiply it by the element
461 // count, but you may have to call XxSize() for each individual element.)
462 static inline int Int32Size ( int32 value);
463 static inline int Int64Size ( int64 value);
464 static inline int UInt32Size (uint32 value);
465 static inline int UInt64Size (uint64 value);
466 static inline int SInt32Size ( int32 value);
467 static inline int SInt64Size ( int64 value);
468 static inline int EnumSize ( int value);
469
470 // These types always have the same size.
471 static const int kFixed32Size = 4;
472 static const int kFixed64Size = 8;
473 static const int kSFixed32Size = 4;
474 static const int kSFixed64Size = 8;
475 static const int kFloatSize = 4;
476 static const int kDoubleSize = 8;
477 static const int kBoolSize = 1;
478
479 static inline int StringSize(const string& value);
480 static inline int BytesSize (const string& value);
481
482 static inline int GroupSize (const MessageLite& value);
483 static inline int MessageSize(const MessageLite& value);
484
485 // Like above, but de-virtualize the call to ByteSize(). The
486 // pointer must point at an instance of MessageType, *not* a subclass (or
487 // the subclass must not override ByteSize()).
488 template<typename MessageType>
489 static inline int GroupSizeNoVirtual (const MessageType& value);
490 template<typename MessageType>
491 static inline int MessageSizeNoVirtual(const MessageType& value);
492
493 // Given the length of data, calculate the byte size of the data on the
494 // wire if we encode the data as a length delimited field.
495 static inline int LengthDelimitedSize(int length);
496
497 private:
498 // A helper method for the repeated primitive reader. This method has
499 // optimizations for primitive types that have fixed size on the wire, and
500 // can be read using potentially faster paths.
501 template <typename CType, enum FieldType DeclaredType>
502 static inline bool ReadRepeatedFixedSizePrimitive(
503 int tag_size,
504 uint32 tag,
505 google::protobuf::io::CodedInputStream* input,
506 RepeatedField<CType>* value) GOOGLE_ATTRIBUTE_ALWAYS_INLINE;
507
508 // Like ReadRepeatedFixedSizePrimitive but for packed primitive fields.
509 template <typename CType, enum FieldType DeclaredType>
510 static inline bool ReadPackedFixedSizePrimitive(
511 google::protobuf::io::CodedInputStream* input,
512 RepeatedField<CType>* value) GOOGLE_ATTRIBUTE_ALWAYS_INLINE;
513
514 static const CppType kFieldTypeToCppTypeMap[];
515 static const WireFormatLite::WireType kWireTypeForFieldType[];
516
517 GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(WireFormatLite);
518 };
519
520 // A class which deals with unknown values. The default implementation just
521 // discards them. WireFormat defines a subclass which writes to an
522 // UnknownFieldSet. This class is used by ExtensionSet::ParseField(), since
523 // ExtensionSet is part of the lite library but UnknownFieldSet is not.
524 class LIBPROTOBUF_EXPORT FieldSkipper {
525 public:
FieldSkipper()526 FieldSkipper() {}
~FieldSkipper()527 virtual ~FieldSkipper() {}
528
529 // Skip a field whose tag has already been consumed.
530 virtual bool SkipField(io::CodedInputStream* input, uint32 tag);
531
532 // Skip an entire message or group, up to an end-group tag (which is consumed)
533 // or end-of-stream.
534 virtual bool SkipMessage(io::CodedInputStream* input);
535
536 // Deal with an already-parsed unrecognized enum value. The default
537 // implementation does nothing, but the UnknownFieldSet-based implementation
538 // saves it as an unknown varint.
539 virtual void SkipUnknownEnum(int field_number, int value);
540 };
541
542 // Subclass of FieldSkipper which saves skipped fields to a CodedOutputStream.
543
544 class LIBPROTOBUF_EXPORT CodedOutputStreamFieldSkipper : public FieldSkipper {
545 public:
CodedOutputStreamFieldSkipper(io::CodedOutputStream * unknown_fields)546 explicit CodedOutputStreamFieldSkipper(io::CodedOutputStream* unknown_fields)
547 : unknown_fields_(unknown_fields) {}
~CodedOutputStreamFieldSkipper()548 virtual ~CodedOutputStreamFieldSkipper() {}
549
550 // implements FieldSkipper -----------------------------------------
551 virtual bool SkipField(io::CodedInputStream* input, uint32 tag);
552 virtual bool SkipMessage(io::CodedInputStream* input);
553 virtual void SkipUnknownEnum(int field_number, int value);
554
555 protected:
556 io::CodedOutputStream* unknown_fields_;
557 };
558
559
560 // inline methods ====================================================
561
562 inline WireFormatLite::CppType
FieldTypeToCppType(FieldType type)563 WireFormatLite::FieldTypeToCppType(FieldType type) {
564 return kFieldTypeToCppTypeMap[type];
565 }
566
MakeTag(int field_number,WireType type)567 inline uint32 WireFormatLite::MakeTag(int field_number, WireType type) {
568 return GOOGLE_PROTOBUF_WIRE_FORMAT_MAKE_TAG(field_number, type);
569 }
570
GetTagWireType(uint32 tag)571 inline WireFormatLite::WireType WireFormatLite::GetTagWireType(uint32 tag) {
572 return static_cast<WireType>(tag & kTagTypeMask);
573 }
574
GetTagFieldNumber(uint32 tag)575 inline int WireFormatLite::GetTagFieldNumber(uint32 tag) {
576 return static_cast<int>(tag >> kTagTypeBits);
577 }
578
TagSize(int field_number,WireFormatLite::FieldType type)579 inline int WireFormatLite::TagSize(int field_number,
580 WireFormatLite::FieldType type) {
581 int result = io::CodedOutputStream::VarintSize32(
582 field_number << kTagTypeBits);
583 if (type == TYPE_GROUP) {
584 // Groups have both a start and an end tag.
585 return result * 2;
586 } else {
587 return result;
588 }
589 }
590
EncodeFloat(float value)591 inline uint32 WireFormatLite::EncodeFloat(float value) {
592 union {float f; uint32 i;};
593 f = value;
594 return i;
595 }
596
DecodeFloat(uint32 value)597 inline float WireFormatLite::DecodeFloat(uint32 value) {
598 union {float f; uint32 i;};
599 i = value;
600 return f;
601 }
602
EncodeDouble(double value)603 inline uint64 WireFormatLite::EncodeDouble(double value) {
604 union {double f; uint64 i;};
605 f = value;
606 return i;
607 }
608
DecodeDouble(uint64 value)609 inline double WireFormatLite::DecodeDouble(uint64 value) {
610 union {double f; uint64 i;};
611 i = value;
612 return f;
613 }
614
615 // ZigZag Transform: Encodes signed integers so that they can be
616 // effectively used with varint encoding.
617 //
618 // varint operates on unsigned integers, encoding smaller numbers into
619 // fewer bytes. If you try to use it on a signed integer, it will treat
620 // this number as a very large unsigned integer, which means that even
621 // small signed numbers like -1 will take the maximum number of bytes
622 // (10) to encode. ZigZagEncode() maps signed integers to unsigned
623 // in such a way that those with a small absolute value will have smaller
624 // encoded values, making them appropriate for encoding using varint.
625 //
626 // int32 -> uint32
627 // -------------------------
628 // 0 -> 0
629 // -1 -> 1
630 // 1 -> 2
631 // -2 -> 3
632 // ... -> ...
633 // 2147483647 -> 4294967294
634 // -2147483648 -> 4294967295
635 //
636 // >> encode >>
637 // << decode <<
638
ZigZagEncode32(int32 n)639 inline uint32 WireFormatLite::ZigZagEncode32(int32 n) {
640 // Note: the right-shift must be arithmetic
641 return (n << 1) ^ (n >> 31);
642 }
643
ZigZagDecode32(uint32 n)644 inline int32 WireFormatLite::ZigZagDecode32(uint32 n) {
645 return (n >> 1) ^ -static_cast<int32>(n & 1);
646 }
647
ZigZagEncode64(int64 n)648 inline uint64 WireFormatLite::ZigZagEncode64(int64 n) {
649 // Note: the right-shift must be arithmetic
650 return (n << 1) ^ (n >> 63);
651 }
652
ZigZagDecode64(uint64 n)653 inline int64 WireFormatLite::ZigZagDecode64(uint64 n) {
654 return (n >> 1) ^ -static_cast<int64>(n & 1);
655 }
656
657 } // namespace internal
658 } // namespace protobuf
659
660 } // namespace google
661 #endif // GOOGLE_PROTOBUF_WIRE_FORMAT_LITE_H__
662