FlatBuffers
An open source project by FPL.
flatbuffers.h
1 /*
2  * Copyright 2014 Google Inc. All rights reserved.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef FLATBUFFERS_H_
18 #define FLATBUFFERS_H_
19 
20 #include "flatbuffers/base.h"
21 
22 namespace flatbuffers {
23 // Wrapper for uoffset_t to allow safe template specialization.
24 // Value is allowed to be 0 to indicate a null object (see e.g. AddOffset).
25 template<typename T> struct Offset {
26  uoffset_t o;
27  Offset() : o(0) {}
28  Offset(uoffset_t _o) : o(_o) {}
29  Offset<void> Union() const { return Offset<void>(o); }
30  bool IsNull() const { return !o; }
31 };
32 
33 inline void EndianCheck() {
34  int endiantest = 1;
35  // If this fails, see FLATBUFFERS_LITTLEENDIAN above.
36  FLATBUFFERS_ASSERT(*reinterpret_cast<char *>(&endiantest) ==
37  FLATBUFFERS_LITTLEENDIAN);
38  (void)endiantest;
39 }
40 
41 template<typename T> FLATBUFFERS_CONSTEXPR size_t AlignOf() {
42  // clang-format off
43  #ifdef _MSC_VER
44  return __alignof(T);
45  #else
46  #ifndef alignof
47  return __alignof__(T);
48  #else
49  return alignof(T);
50  #endif
51  #endif
52  // clang-format on
53 }
54 
55 // When we read serialized data from memory, in the case of most scalars,
56 // we want to just read T, but in the case of Offset, we want to actually
57 // perform the indirection and return a pointer.
58 // The template specialization below does just that.
59 // It is wrapped in a struct since function templates can't overload on the
60 // return type like this.
61 // The typedef is for the convenience of callers of this function
62 // (avoiding the need for a trailing return decltype)
63 template<typename T> struct IndirectHelper {
64  typedef T return_type;
65  typedef T mutable_return_type;
66  static const size_t element_stride = sizeof(T);
67  static return_type Read(const uint8_t *p, uoffset_t i) {
68  return EndianScalar((reinterpret_cast<const T *>(p))[i]);
69  }
70 };
71 template<typename T> struct IndirectHelper<Offset<T>> {
72  typedef const T *return_type;
73  typedef T *mutable_return_type;
74  static const size_t element_stride = sizeof(uoffset_t);
75  static return_type Read(const uint8_t *p, uoffset_t i) {
76  p += i * sizeof(uoffset_t);
77  return reinterpret_cast<return_type>(p + ReadScalar<uoffset_t>(p));
78  }
79 };
80 template<typename T> struct IndirectHelper<const T *> {
81  typedef const T *return_type;
82  typedef T *mutable_return_type;
83  static const size_t element_stride = sizeof(T);
84  static return_type Read(const uint8_t *p, uoffset_t i) {
85  return reinterpret_cast<const T *>(p + i * sizeof(T));
86  }
87 };
88 
89 // An STL compatible iterator implementation for Vector below, effectively
90 // calling Get() for every element.
91 template<typename T, typename IT> struct VectorIterator {
92  typedef std::random_access_iterator_tag iterator_category;
93  typedef IT value_type;
94  typedef ptrdiff_t difference_type;
95  typedef IT *pointer;
96  typedef IT &reference;
97 
98  VectorIterator(const uint8_t *data, uoffset_t i)
99  : data_(data + IndirectHelper<T>::element_stride * i) {}
100  VectorIterator(const VectorIterator &other) : data_(other.data_) {}
101 
102  VectorIterator &operator=(const VectorIterator &other) {
103  data_ = other.data_;
104  return *this;
105  }
106 
107  VectorIterator &operator=(VectorIterator &&other) {
108  data_ = other.data_;
109  return *this;
110  }
111 
112  bool operator==(const VectorIterator &other) const {
113  return data_ == other.data_;
114  }
115 
116  bool operator<(const VectorIterator &other) const {
117  return data_ < other.data_;
118  }
119 
120  bool operator!=(const VectorIterator &other) const {
121  return data_ != other.data_;
122  }
123 
124  difference_type operator-(const VectorIterator &other) const {
125  return (data_ - other.data_) / IndirectHelper<T>::element_stride;
126  }
127 
128  IT operator*() const { return IndirectHelper<T>::Read(data_, 0); }
129 
130  IT operator->() const { return IndirectHelper<T>::Read(data_, 0); }
131 
132  VectorIterator &operator++() {
134  return *this;
135  }
136 
137  VectorIterator operator++(int) {
138  VectorIterator temp(data_, 0);
140  return temp;
141  }
142 
143  VectorIterator operator+(const uoffset_t &offset) const {
144  return VectorIterator(data_ + offset * IndirectHelper<T>::element_stride,
145  0);
146  }
147 
148  VectorIterator &operator+=(const uoffset_t &offset) {
149  data_ += offset * IndirectHelper<T>::element_stride;
150  return *this;
151  }
152 
153  VectorIterator &operator--() {
155  return *this;
156  }
157 
158  VectorIterator operator--(int) {
159  VectorIterator temp(data_, 0);
161  return temp;
162  }
163 
164  VectorIterator operator-(const uoffset_t &offset) {
165  return VectorIterator(data_ - offset * IndirectHelper<T>::element_stride,
166  0);
167  }
168 
169  VectorIterator &operator-=(const uoffset_t &offset) {
170  data_ -= offset * IndirectHelper<T>::element_stride;
171  return *this;
172  }
173 
174  private:
175  const uint8_t *data_;
176 };
177 
178 struct String;
179 
180 // This is used as a helper type for accessing vectors.
181 // Vector::data() assumes the vector elements start after the length field.
182 template<typename T> class Vector {
183  public:
185  iterator;
188 
189  uoffset_t size() const { return EndianScalar(length_); }
190 
191  // Deprecated: use size(). Here for backwards compatibility.
192  uoffset_t Length() const { return size(); }
193 
194  typedef typename IndirectHelper<T>::return_type return_type;
195  typedef typename IndirectHelper<T>::mutable_return_type mutable_return_type;
196 
197  return_type Get(uoffset_t i) const {
198  FLATBUFFERS_ASSERT(i < size());
199  return IndirectHelper<T>::Read(Data(), i);
200  }
201 
202  return_type operator[](uoffset_t i) const { return Get(i); }
203 
204  // If this is a Vector of enums, T will be its storage type, not the enum
205  // type. This function makes it convenient to retrieve value with enum
206  // type E.
207  template<typename E> E GetEnum(uoffset_t i) const {
208  return static_cast<E>(Get(i));
209  }
210 
211  // If this a vector of unions, this does the cast for you. There's no check
212  // to make sure this is the right type!
213  template<typename U> const U *GetAs(uoffset_t i) const {
214  return reinterpret_cast<const U *>(Get(i));
215  }
216 
217  // If this a vector of unions, this does the cast for you. There's no check
218  // to make sure this is actually a string!
219  const String *GetAsString(uoffset_t i) const {
220  return reinterpret_cast<const String *>(Get(i));
221  }
222 
223  const void *GetStructFromOffset(size_t o) const {
224  return reinterpret_cast<const void *>(Data() + o);
225  }
226 
227  iterator begin() { return iterator(Data(), 0); }
228  const_iterator begin() const { return const_iterator(Data(), 0); }
229 
230  iterator end() { return iterator(Data(), size()); }
231  const_iterator end() const { return const_iterator(Data(), size()); }
232 
233  // Change elements if you have a non-const pointer to this object.
234  // Scalars only. See reflection.h, and the documentation.
235  void Mutate(uoffset_t i, const T &val) {
236  FLATBUFFERS_ASSERT(i < size());
237  WriteScalar(data() + i, val);
238  }
239 
240  // Change an element of a vector of tables (or strings).
241  // "val" points to the new table/string, as you can obtain from
242  // e.g. reflection::AddFlatBuffer().
243  void MutateOffset(uoffset_t i, const uint8_t *val) {
244  FLATBUFFERS_ASSERT(i < size());
245  static_assert(sizeof(T) == sizeof(uoffset_t), "Unrelated types");
246  WriteScalar(data() + i,
247  static_cast<uoffset_t>(val - (Data() + i * sizeof(uoffset_t))));
248  }
249 
250  // Get a mutable pointer to tables/strings inside this vector.
251  mutable_return_type GetMutableObject(uoffset_t i) const {
252  FLATBUFFERS_ASSERT(i < size());
253  return const_cast<mutable_return_type>(IndirectHelper<T>::Read(Data(), i));
254  }
255 
256  // The raw data in little endian format. Use with care.
257  const uint8_t *Data() const {
258  return reinterpret_cast<const uint8_t *>(&length_ + 1);
259  }
260 
261  uint8_t *Data() { return reinterpret_cast<uint8_t *>(&length_ + 1); }
262 
263  // Similarly, but typed, much like std::vector::data
264  const T *data() const { return reinterpret_cast<const T *>(Data()); }
265  T *data() { return reinterpret_cast<T *>(Data()); }
266 
267  template<typename K> return_type LookupByKey(K key) const {
268  void *search_result = std::bsearch(
269  &key, Data(), size(), IndirectHelper<T>::element_stride, KeyCompare<K>);
270 
271  if (!search_result) {
272  return nullptr; // Key not found.
273  }
274 
275  const uint8_t *element = reinterpret_cast<const uint8_t *>(search_result);
276 
277  return IndirectHelper<T>::Read(element, 0);
278  }
279 
280  protected:
281  // This class is only used to access pre-existing data. Don't ever
282  // try to construct these manually.
283  Vector();
284 
285  uoffset_t length_;
286 
287  private:
288  // This class is a pointer. Copying will therefore create an invalid object.
289  // Private and unimplemented copy constructor.
290  Vector(const Vector &);
291 
292  template<typename K> static int KeyCompare(const void *ap, const void *bp) {
293  const K *key = reinterpret_cast<const K *>(ap);
294  const uint8_t *data = reinterpret_cast<const uint8_t *>(bp);
295  auto table = IndirectHelper<T>::Read(data, 0);
296 
297  // std::bsearch compares with the operands transposed, so we negate the
298  // result here.
299  return -table->KeyCompareWithValue(*key);
300  }
301 };
302 
303 // Represent a vector much like the template above, but in this case we
304 // don't know what the element types are (used with reflection.h).
305 class VectorOfAny {
306  public:
307  uoffset_t size() const { return EndianScalar(length_); }
308 
309  const uint8_t *Data() const {
310  return reinterpret_cast<const uint8_t *>(&length_ + 1);
311  }
312  uint8_t *Data() { return reinterpret_cast<uint8_t *>(&length_ + 1); }
313 
314  protected:
315  VectorOfAny();
316 
317  uoffset_t length_;
318 
319  private:
320  VectorOfAny(const VectorOfAny &);
321 };
322 
323 #ifndef FLATBUFFERS_CPP98_STL
324 template<typename T, typename U>
325 Vector<Offset<T>> *VectorCast(Vector<Offset<U>> *ptr) {
326  static_assert(std::is_base_of<T, U>::value, "Unrelated types");
327  return reinterpret_cast<Vector<Offset<T>> *>(ptr);
328 }
329 
330 template<typename T, typename U>
331 const Vector<Offset<T>> *VectorCast(const Vector<Offset<U>> *ptr) {
332  static_assert(std::is_base_of<T, U>::value, "Unrelated types");
333  return reinterpret_cast<const Vector<Offset<T>> *>(ptr);
334 }
335 #endif
336 
337 // Convenient helper function to get the length of any vector, regardless
338 // of whether it is null or not (the field is not set).
339 template<typename T> static inline size_t VectorLength(const Vector<T> *v) {
340  return v ? v->Length() : 0;
341 }
342 
343 struct String : public Vector<char> {
344  const char *c_str() const { return reinterpret_cast<const char *>(Data()); }
345  std::string str() const { return std::string(c_str(), Length()); }
346 
347  // clang-format off
348  #ifdef FLATBUFFERS_HAS_STRING_VIEW
349  flatbuffers::string_view string_view() const {
350  return flatbuffers::string_view(c_str(), Length());
351  }
352  #endif // FLATBUFFERS_HAS_STRING_VIEW
353  // clang-format on
354 
355  bool operator<(const String &o) const {
356  return strcmp(c_str(), o.c_str()) < 0;
357  }
358 };
359 
360 // Convenience function to get std::string from a String returning an empty
361 // string on null pointer.
362 static inline std::string GetString(const String * str) {
363  return str ? str->str() : "";
364 }
365 
366 // Convenience function to get char* from a String returning an empty string on
367 // null pointer.
368 static inline const char * GetCstring(const String * str) {
369  return str ? str->c_str() : "";
370 }
371 
372 // Allocator interface. This is flatbuffers-specific and meant only for
373 // `vector_downward` usage.
374 class Allocator {
375  public:
376  virtual ~Allocator() {}
377 
378  // Allocate `size` bytes of memory.
379  virtual uint8_t *allocate(size_t size) = 0;
380 
381  // Deallocate `size` bytes of memory at `p` allocated by this allocator.
382  virtual void deallocate(uint8_t *p, size_t size) = 0;
383 
384  // Reallocate `new_size` bytes of memory, replacing the old region of size
385  // `old_size` at `p`. In contrast to a normal realloc, this grows downwards,
386  // and is intended specifcally for `vector_downward` use.
387  // `in_use_back` and `in_use_front` indicate how much of `old_size` is
388  // actually in use at each end, and needs to be copied.
389  virtual uint8_t *reallocate_downward(uint8_t *old_p, size_t old_size,
390  size_t new_size, size_t in_use_back,
391  size_t in_use_front) {
392  FLATBUFFERS_ASSERT(new_size > old_size); // vector_downward only grows
393  uint8_t *new_p = allocate(new_size);
394  memcpy_downward(old_p, old_size, new_p, new_size, in_use_back,
395  in_use_front);
396  deallocate(old_p, old_size);
397  return new_p;
398  }
399 
400  protected:
401  // Called by `reallocate_downward` to copy memory from `old_p` of `old_size`
402  // to `new_p` of `new_size`. Only memory of size `in_use_front` and
403  // `in_use_back` will be copied from the front and back of the old memory
404  // allocation.
405  void memcpy_downward(uint8_t *old_p, size_t old_size,
406  uint8_t *new_p, size_t new_size,
407  size_t in_use_back, size_t in_use_front) {
408  memcpy(new_p + new_size - in_use_back, old_p + old_size - in_use_back,
409  in_use_back);
410  memcpy(new_p, old_p, in_use_front);
411  }
412 };
413 
414 // DefaultAllocator uses new/delete to allocate memory regions
415 class DefaultAllocator : public Allocator {
416  public:
417  uint8_t *allocate(size_t size) FLATBUFFERS_OVERRIDE {
418  return new uint8_t[size];
419  }
420 
421  void deallocate(uint8_t *p, size_t) FLATBUFFERS_OVERRIDE {
422  delete[] p;
423  }
424 };
425 
426 // These functions allow for a null allocator to mean use the default allocator,
427 // as used by DetachedBuffer and vector_downward below.
428 // This is to avoid having a statically or dynamically allocated default
429 // allocator, or having to move it between the classes that may own it.
430 inline uint8_t *Allocate(Allocator *allocator, size_t size) {
431  return allocator ? allocator->allocate(size)
432  : DefaultAllocator().allocate(size);
433 }
434 
435 inline void Deallocate(Allocator *allocator, uint8_t *p, size_t size) {
436  if (allocator) allocator->deallocate(p, size);
437  else DefaultAllocator().deallocate(p, size);
438 }
439 
440 inline uint8_t *ReallocateDownward(Allocator *allocator, uint8_t *old_p,
441  size_t old_size, size_t new_size,
442  size_t in_use_back, size_t in_use_front) {
443  return allocator
444  ? allocator->reallocate_downward(old_p, old_size, new_size,
445  in_use_back, in_use_front)
446  : DefaultAllocator().reallocate_downward(old_p, old_size, new_size,
447  in_use_back, in_use_front);
448 }
449 
450 // DetachedBuffer is a finished flatbuffer memory region, detached from its
451 // builder. The original memory region and allocator are also stored so that
452 // the DetachedBuffer can manage the memory lifetime.
454  public:
456  : allocator_(nullptr),
457  own_allocator_(false),
458  buf_(nullptr),
459  reserved_(0),
460  cur_(nullptr),
461  size_(0) {}
462 
463  DetachedBuffer(Allocator *allocator, bool own_allocator, uint8_t *buf,
464  size_t reserved, uint8_t *cur, size_t sz)
465  : allocator_(allocator),
466  own_allocator_(own_allocator),
467  buf_(buf),
468  reserved_(reserved),
469  cur_(cur),
470  size_(sz) {}
471 
473  : allocator_(other.allocator_),
474  own_allocator_(other.own_allocator_),
475  buf_(other.buf_),
476  reserved_(other.reserved_),
477  cur_(other.cur_),
478  size_(other.size_) {
479  other.reset();
480  }
481 
482  DetachedBuffer &operator=(DetachedBuffer &&other) {
483  destroy();
484 
485  allocator_ = other.allocator_;
486  own_allocator_ = other.own_allocator_;
487  buf_ = other.buf_;
488  reserved_ = other.reserved_;
489  cur_ = other.cur_;
490  size_ = other.size_;
491 
492  other.reset();
493 
494  return *this;
495  }
496 
497  ~DetachedBuffer() { destroy(); }
498 
499  const uint8_t *data() const { return cur_; }
500 
501  uint8_t *data() { return cur_; }
502 
503  size_t size() const { return size_; }
504 
505  // clang-format off
506  #if 0 // disabled for now due to the ordering of classes in this header
507  template <class T>
508  bool Verify() const {
509  Verifier verifier(data(), size());
510  return verifier.Verify<T>(nullptr);
511  }
512 
513  template <class T>
514  const T* GetRoot() const {
515  return flatbuffers::GetRoot<T>(data());
516  }
517 
518  template <class T>
519  T* GetRoot() {
520  return flatbuffers::GetRoot<T>(data());
521  }
522  #endif
523  // clang-format on
524 
525  // These may change access mode, leave these at end of public section
526  FLATBUFFERS_DELETE_FUNC(DetachedBuffer(const DetachedBuffer &other))
527  FLATBUFFERS_DELETE_FUNC(
528  DetachedBuffer &operator=(const DetachedBuffer &other))
529 
530  protected:
531  Allocator *allocator_;
532  bool own_allocator_;
533  uint8_t *buf_;
534  size_t reserved_;
535  uint8_t *cur_;
536  size_t size_;
537 
538  inline void destroy() {
539  if (buf_) Deallocate(allocator_, buf_, reserved_);
540  if (own_allocator_ && allocator_) { delete allocator_; }
541  reset();
542  }
543 
544  inline void reset() {
545  allocator_ = nullptr;
546  own_allocator_ = false;
547  buf_ = nullptr;
548  reserved_ = 0;
549  cur_ = nullptr;
550  size_ = 0;
551  }
552 };
553 
554 // This is a minimal replication of std::vector<uint8_t> functionality,
555 // except growing from higher to lower addresses. i.e push_back() inserts data
556 // in the lowest address in the vector.
557 // Since this vector leaves the lower part unused, we support a "scratch-pad"
558 // that can be stored there for temporary data, to share the allocated space.
559 // Essentially, this supports 2 std::vectors in a single buffer.
561  public:
562  explicit vector_downward(size_t initial_size,
563  Allocator *allocator,
564  bool own_allocator,
565  size_t buffer_minalign)
566  : allocator_(allocator),
567  own_allocator_(own_allocator),
568  initial_size_(initial_size),
569  buffer_minalign_(buffer_minalign),
570  reserved_(0),
571  buf_(nullptr),
572  cur_(nullptr),
573  scratch_(nullptr) {}
574 
576  : allocator_(other.allocator_),
577  own_allocator_(other.own_allocator_),
578  initial_size_(other.initial_size_),
579  buffer_minalign_(other.buffer_minalign_),
580  reserved_(other.reserved_),
581  buf_(other.buf_),
582  cur_(other.cur_),
583  scratch_(other.scratch_) {
584  other.allocator_ = nullptr;
585  other.own_allocator_ = false;
586  // No change in other.initial_size_
587  // No change in other.buffer_minalign_
588  other.reserved_ = 0;
589  other.buf_ = nullptr;
590  other.cur_ = nullptr;
591  other.scratch_ = nullptr;
592  }
593 
594  vector_downward &operator=(vector_downward &&other) {
595  // Move construct a temporary and swap idiom
596  vector_downward temp(std::move(other));
597  swap(temp);
598  return *this;
599  }
600 
601  ~vector_downward() {
602  clear_buffer();
603  clear_allocator();
604  }
605 
606  void reset() {
607  clear_buffer();
608  clear();
609  }
610 
611  void clear() {
612  if (buf_) {
613  cur_ = buf_ + reserved_;
614  } else {
615  reserved_ = 0;
616  cur_ = nullptr;
617  }
618  clear_scratch();
619  }
620 
621  void clear_scratch() {
622  scratch_ = buf_;
623  }
624 
625  void clear_allocator() {
626  if (own_allocator_ && allocator_) { delete allocator_; }
627  allocator_ = nullptr;
628  own_allocator_ = false;
629  }
630 
631  void clear_buffer() {
632  if (buf_) Deallocate(allocator_, buf_, reserved_);
633  buf_ = nullptr;
634  }
635 
636  // Relinquish the pointer to the caller.
637  uint8_t *release_raw(size_t &allocated_bytes, size_t &offset) {
638  auto *buf = buf_;
639  allocated_bytes = reserved_;
640  offset = static_cast<size_t>(cur_ - buf_);
641 
642  buf_ = nullptr;
643  clear_allocator();
644  clear();
645  return buf;
646  }
647 
648  // Relinquish the pointer to the caller.
649  DetachedBuffer release() {
650  DetachedBuffer fb(allocator_, own_allocator_, buf_, reserved_, cur_,
651  size());
652  allocator_ = nullptr;
653  own_allocator_ = false;
654  buf_ = nullptr;
655  clear();
656  return fb;
657  }
658 
659  size_t ensure_space(size_t len) {
660  FLATBUFFERS_ASSERT(cur_ >= scratch_ && scratch_ >= buf_);
661  if (len > static_cast<size_t>(cur_ - scratch_)) { reallocate(len); }
662  // Beyond this, signed offsets may not have enough range:
663  // (FlatBuffers > 2GB not supported).
664  FLATBUFFERS_ASSERT(size() < FLATBUFFERS_MAX_BUFFER_SIZE);
665  return len;
666  }
667 
668  inline uint8_t *make_space(size_t len) {
669  size_t space = ensure_space(len);
670  cur_ -= space;
671  return cur_;
672  }
673 
674  // Returns nullptr if using the DefaultAllocator.
675  Allocator *get_custom_allocator() { return allocator_; }
676 
677  uoffset_t size() const {
678  return static_cast<uoffset_t>(reserved_ - (cur_ - buf_));
679  }
680 
681  uoffset_t scratch_size() const {
682  return static_cast<uoffset_t>(scratch_ - buf_);
683  }
684 
685  size_t capacity() const { return reserved_; }
686 
687  uint8_t *data() const {
688  FLATBUFFERS_ASSERT(cur_);
689  return cur_;
690  }
691 
692  uint8_t *scratch_data() const {
693  FLATBUFFERS_ASSERT(buf_);
694  return buf_;
695  }
696 
697  uint8_t *scratch_end() const {
698  FLATBUFFERS_ASSERT(scratch_);
699  return scratch_;
700  }
701 
702  uint8_t *data_at(size_t offset) const { return buf_ + reserved_ - offset; }
703 
704  void push(const uint8_t *bytes, size_t num) {
705  memcpy(make_space(num), bytes, num);
706  }
707 
708  // Specialized version of push() that avoids memcpy call for small data.
709  template<typename T> void push_small(const T &little_endian_t) {
710  make_space(sizeof(T));
711  *reinterpret_cast<T *>(cur_) = little_endian_t;
712  }
713 
714  template<typename T> void scratch_push_small(const T &t) {
715  ensure_space(sizeof(T));
716  *reinterpret_cast<T *>(scratch_) = t;
717  scratch_ += sizeof(T);
718  }
719 
720  // fill() is most frequently called with small byte counts (<= 4),
721  // which is why we're using loops rather than calling memset.
722  void fill(size_t zero_pad_bytes) {
723  make_space(zero_pad_bytes);
724  for (size_t i = 0; i < zero_pad_bytes; i++) cur_[i] = 0;
725  }
726 
727  // Version for when we know the size is larger.
728  void fill_big(size_t zero_pad_bytes) {
729  memset(make_space(zero_pad_bytes), 0, zero_pad_bytes);
730  }
731 
732  void pop(size_t bytes_to_remove) { cur_ += bytes_to_remove; }
733  void scratch_pop(size_t bytes_to_remove) { scratch_ -= bytes_to_remove; }
734 
735  void swap(vector_downward &other) {
736  using std::swap;
737  swap(allocator_, other.allocator_);
738  swap(own_allocator_, other.own_allocator_);
739  swap(initial_size_, other.initial_size_);
740  swap(buffer_minalign_, other.buffer_minalign_);
741  swap(reserved_, other.reserved_);
742  swap(buf_, other.buf_);
743  swap(cur_, other.cur_);
744  swap(scratch_, other.scratch_);
745  }
746 
747  void swap_allocator(vector_downward &other) {
748  using std::swap;
749  swap(allocator_, other.allocator_);
750  swap(own_allocator_, other.own_allocator_);
751  }
752 
753  private:
754  // You shouldn't really be copying instances of this class.
755  FLATBUFFERS_DELETE_FUNC(vector_downward(const vector_downward &))
756  FLATBUFFERS_DELETE_FUNC(vector_downward &operator=(const vector_downward &))
757 
758  Allocator *allocator_;
759  bool own_allocator_;
760  size_t initial_size_;
761  size_t buffer_minalign_;
762  size_t reserved_;
763  uint8_t *buf_;
764  uint8_t *cur_; // Points at location between empty (below) and used (above).
765  uint8_t *scratch_; // Points to the end of the scratchpad in use.
766 
767  void reallocate(size_t len) {
768  auto old_reserved = reserved_;
769  auto old_size = size();
770  auto old_scratch_size = scratch_size();
771  reserved_ += (std::max)(len,
772  old_reserved ? old_reserved / 2 : initial_size_);
773  reserved_ = (reserved_ + buffer_minalign_ - 1) & ~(buffer_minalign_ - 1);
774  if (buf_) {
775  buf_ = ReallocateDownward(allocator_, buf_, old_reserved, reserved_,
776  old_size, old_scratch_size);
777  } else {
778  buf_ = Allocate(allocator_, reserved_);
779  }
780  cur_ = buf_ + reserved_ - old_size;
781  scratch_ = buf_ + old_scratch_size;
782  }
783 };
784 
785 // Converts a Field ID to a virtual table offset.
786 inline voffset_t FieldIndexToOffset(voffset_t field_id) {
787  // Should correspond to what EndTable() below builds up.
788  const int fixed_fields = 2; // Vtable size and Object Size.
789  return static_cast<voffset_t>((field_id + fixed_fields) * sizeof(voffset_t));
790 }
791 
792 template<typename T, typename Alloc>
793 const T *data(const std::vector<T, Alloc> &v) {
794  return v.empty() ? nullptr : &v.front();
795 }
796 template<typename T, typename Alloc> T *data(std::vector<T, Alloc> &v) {
797  return v.empty() ? nullptr : &v.front();
798 }
799 
800 /// @endcond
801 
802 /// @addtogroup flatbuffers_cpp_api
803 /// @{
804 /// @class FlatBufferBuilder
805 /// @brief Helper class to hold data needed in creation of a FlatBuffer.
806 /// To serialize data, you typically call one of the `Create*()` functions in
807 /// the generated code, which in turn call a sequence of `StartTable`/
808 /// `PushElement`/`AddElement`/`EndTable`, or the builtin `CreateString`/
809 /// `CreateVector` functions. Do this is depth-first order to build up a tree to
810 /// the root. `Finish()` wraps up the buffer ready for transport.
812  public:
813  /// @brief Default constructor for FlatBufferBuilder.
814  /// @param[in] initial_size The initial size of the buffer, in bytes. Defaults
815  /// to `1024`.
816  /// @param[in] allocator An `Allocator` to use. If null will use
817  /// `DefaultAllocator`.
818  /// @param[in] own_allocator Whether the builder/vector should own the
819  /// allocator. Defaults to / `false`.
820  /// @param[in] buffer_minalign Force the buffer to be aligned to the given
821  /// minimum alignment upon reallocation. Only needed if you intend to store
822  /// types with custom alignment AND you wish to read the buffer in-place
823  /// directly after creation.
824  explicit FlatBufferBuilder(size_t initial_size = 1024,
825  Allocator *allocator = nullptr,
826  bool own_allocator = false,
827  size_t buffer_minalign =
828  AlignOf<largest_scalar_t>())
829  : buf_(initial_size, allocator, own_allocator, buffer_minalign),
830  num_field_loc(0),
831  max_voffset_(0),
832  nested(false),
833  finished(false),
834  minalign_(1),
835  force_defaults_(false),
836  dedup_vtables_(true),
837  string_pool(nullptr) {
838  EndianCheck();
839  }
840 
841  /// @brief Move constructor for FlatBufferBuilder.
843  : buf_(1024, nullptr, false, AlignOf<largest_scalar_t>()),
844  num_field_loc(0),
845  max_voffset_(0),
846  nested(false),
847  finished(false),
848  minalign_(1),
849  force_defaults_(false),
850  dedup_vtables_(true),
851  string_pool(nullptr) {
852  EndianCheck();
853  // Default construct and swap idiom.
854  // Lack of delegating constructors in vs2010 makes it more verbose than needed.
855  Swap(other);
856  }
857 
858  /// @brief Move assignment operator for FlatBufferBuilder.
860  // Move construct a temporary and swap idiom
861  FlatBufferBuilder temp(std::move(other));
862  Swap(temp);
863  return *this;
864  }
865 
866  void Swap(FlatBufferBuilder &other) {
867  using std::swap;
868  buf_.swap(other.buf_);
869  swap(num_field_loc, other.num_field_loc);
870  swap(max_voffset_, other.max_voffset_);
871  swap(nested, other.nested);
872  swap(finished, other.finished);
873  swap(minalign_, other.minalign_);
874  swap(force_defaults_, other.force_defaults_);
875  swap(dedup_vtables_, other.dedup_vtables_);
876  swap(string_pool, other.string_pool);
877  }
878 
879  ~FlatBufferBuilder() {
880  if (string_pool) delete string_pool;
881  }
882 
883  void Reset() {
884  Clear(); // clear builder state
885  buf_.reset(); // deallocate buffer
886  }
887 
888  /// @brief Reset all the state in this FlatBufferBuilder so it can be reused
889  /// to construct another buffer.
890  void Clear() {
891  ClearOffsets();
892  buf_.clear();
893  nested = false;
894  finished = false;
895  minalign_ = 1;
896  if (string_pool) string_pool->clear();
897  }
898 
899  /// @brief The current size of the serialized buffer, counting from the end.
900  /// @return Returns an `uoffset_t` with the current size of the buffer.
901  uoffset_t GetSize() const { return buf_.size(); }
902 
903  /// @brief Get the serialized buffer (after you call `Finish()`).
904  /// @return Returns an `uint8_t` pointer to the FlatBuffer data inside the
905  /// buffer.
906  uint8_t *GetBufferPointer() const {
907  Finished();
908  return buf_.data();
909  }
910 
911  /// @brief Get a pointer to an unfinished buffer.
912  /// @return Returns a `uint8_t` pointer to the unfinished buffer.
913  uint8_t *GetCurrentBufferPointer() const { return buf_.data(); }
914 
915  /// @brief Get the released pointer to the serialized buffer.
916  /// @warning Do NOT attempt to use this FlatBufferBuilder afterwards!
917  /// @return A `FlatBuffer` that owns the buffer and its allocator and
918  /// behaves similar to a `unique_ptr` with a deleter.
919  /// Deprecated: use Release() instead
921  Finished();
922  return buf_.release();
923  }
924 
925  /// @brief Get the released DetachedBuffer.
926  /// @return A `DetachedBuffer` that owns the buffer and its allocator.
928  Finished();
929  return buf_.release();
930  }
931 
932  /// @brief Get the released pointer to the serialized buffer.
933  /// @param The size of the memory block containing
934  /// the serialized `FlatBuffer`.
935  /// @param The offset from the released pointer where the finished
936  /// `FlatBuffer` starts.
937  /// @return A raw pointer to the start of the memory block containing
938  /// the serialized `FlatBuffer`.
939  /// @remark If the allocator is owned, it gets deleted during this call.
940  uint8_t *ReleaseRaw(size_t &size, size_t &offset) {
941  Finished();
942  return buf_.release_raw(size, offset);
943  }
944 
945  /// @brief get the minimum alignment this buffer needs to be accessed
946  /// properly. This is only known once all elements have been written (after
947  /// you call Finish()). You can use this information if you need to embed
948  /// a FlatBuffer in some other buffer, such that you can later read it
949  /// without first having to copy it into its own buffer.
951  Finished();
952  return minalign_;
953  }
954 
955  /// @cond FLATBUFFERS_INTERNAL
956  void Finished() const {
957  // If you get this assert, you're attempting to get access a buffer
958  // which hasn't been finished yet. Be sure to call
959  // FlatBufferBuilder::Finish with your root table.
960  // If you really need to access an unfinished buffer, call
961  // GetCurrentBufferPointer instead.
962  FLATBUFFERS_ASSERT(finished);
963  }
964  /// @endcond
965 
966  /// @brief In order to save space, fields that are set to their default value
967  /// don't get serialized into the buffer.
968  /// @param[in] bool fd When set to `true`, always serializes default values that are set.
969  /// Optional fields which are not set explicitly, will still not be serialized.
970  void ForceDefaults(bool fd) { force_defaults_ = fd; }
971 
972  /// @brief By default vtables are deduped in order to save space.
973  /// @param[in] bool dedup When set to `true`, dedup vtables.
974  void DedupVtables(bool dedup) { dedup_vtables_ = dedup; }
975 
976  /// @cond FLATBUFFERS_INTERNAL
977  void Pad(size_t num_bytes) { buf_.fill(num_bytes); }
978 
979  void TrackMinAlign(size_t elem_size) {
980  if (elem_size > minalign_) minalign_ = elem_size;
981  }
982 
983  void Align(size_t elem_size) {
984  TrackMinAlign(elem_size);
985  buf_.fill(PaddingBytes(buf_.size(), elem_size));
986  }
987 
988  void PushFlatBuffer(const uint8_t *bytes, size_t size) {
989  PushBytes(bytes, size);
990  finished = true;
991  }
992 
993  void PushBytes(const uint8_t *bytes, size_t size) { buf_.push(bytes, size); }
994 
995  void PopBytes(size_t amount) { buf_.pop(amount); }
996 
997  template<typename T> void AssertScalarT() {
998  // The code assumes power of 2 sizes and endian-swap-ability.
999  static_assert(flatbuffers::is_scalar<T>::value, "T must be a scalar type");
1000  }
1001 
1002  // Write a single aligned scalar to the buffer
1003  template<typename T> uoffset_t PushElement(T element) {
1004  AssertScalarT<T>();
1005  T litle_endian_element = EndianScalar(element);
1006  Align(sizeof(T));
1007  buf_.push_small(litle_endian_element);
1008  return GetSize();
1009  }
1010 
1011  template<typename T> uoffset_t PushElement(Offset<T> off) {
1012  // Special case for offsets: see ReferTo below.
1013  return PushElement(ReferTo(off.o));
1014  }
1015 
1016  // When writing fields, we track where they are, so we can create correct
1017  // vtables later.
1018  void TrackField(voffset_t field, uoffset_t off) {
1019  FieldLoc fl = { off, field };
1020  buf_.scratch_push_small(fl);
1021  num_field_loc++;
1022  max_voffset_ = (std::max)(max_voffset_, field);
1023  }
1024 
1025  // Like PushElement, but additionally tracks the field this represents.
1026  template<typename T> void AddElement(voffset_t field, T e, T def) {
1027  // We don't serialize values equal to the default.
1028  if (e == def && !force_defaults_) return;
1029  auto off = PushElement(e);
1030  TrackField(field, off);
1031  }
1032 
1033  template<typename T> void AddOffset(voffset_t field, Offset<T> off) {
1034  if (off.IsNull()) return; // Don't store.
1035  AddElement(field, ReferTo(off.o), static_cast<uoffset_t>(0));
1036  }
1037 
1038  template<typename T> void AddStruct(voffset_t field, const T *structptr) {
1039  if (!structptr) return; // Default, don't store.
1040  Align(AlignOf<T>());
1041  buf_.push_small(*structptr);
1042  TrackField(field, GetSize());
1043  }
1044 
1045  void AddStructOffset(voffset_t field, uoffset_t off) {
1046  TrackField(field, off);
1047  }
1048 
1049  // Offsets initially are relative to the end of the buffer (downwards).
1050  // This function converts them to be relative to the current location
1051  // in the buffer (when stored here), pointing upwards.
1052  uoffset_t ReferTo(uoffset_t off) {
1053  // Align to ensure GetSize() below is correct.
1054  Align(sizeof(uoffset_t));
1055  // Offset must refer to something already in buffer.
1056  FLATBUFFERS_ASSERT(off && off <= GetSize());
1057  return GetSize() - off + static_cast<uoffset_t>(sizeof(uoffset_t));
1058  }
1059 
1060  void NotNested() {
1061  // If you hit this, you're trying to construct a Table/Vector/String
1062  // during the construction of its parent table (between the MyTableBuilder
1063  // and table.Finish().
1064  // Move the creation of these sub-objects to above the MyTableBuilder to
1065  // not get this assert.
1066  // Ignoring this assert may appear to work in simple cases, but the reason
1067  // it is here is that storing objects in-line may cause vtable offsets
1068  // to not fit anymore. It also leads to vtable duplication.
1069  FLATBUFFERS_ASSERT(!nested);
1070  // If you hit this, fields were added outside the scope of a table.
1071  FLATBUFFERS_ASSERT(!num_field_loc);
1072  }
1073 
1074  // From generated code (or from the parser), we call StartTable/EndTable
1075  // with a sequence of AddElement calls in between.
1076  uoffset_t StartTable() {
1077  NotNested();
1078  nested = true;
1079  return GetSize();
1080  }
1081 
1082  // This finishes one serialized object by generating the vtable if it's a
1083  // table, comparing it against existing vtables, and writing the
1084  // resulting vtable offset.
1085  uoffset_t EndTable(uoffset_t start) {
1086  // If you get this assert, a corresponding StartTable wasn't called.
1087  FLATBUFFERS_ASSERT(nested);
1088  // Write the vtable offset, which is the start of any Table.
1089  // We fill it's value later.
1090  auto vtableoffsetloc = PushElement<soffset_t>(0);
1091  // Write a vtable, which consists entirely of voffset_t elements.
1092  // It starts with the number of offsets, followed by a type id, followed
1093  // by the offsets themselves. In reverse:
1094  // Include space for the last offset and ensure empty tables have a
1095  // minimum size.
1096  max_voffset_ =
1097  (std::max)(static_cast<voffset_t>(max_voffset_ + sizeof(voffset_t)),
1098  FieldIndexToOffset(0));
1099  buf_.fill_big(max_voffset_);
1100  auto table_object_size = vtableoffsetloc - start;
1101  // Vtable use 16bit offsets.
1102  FLATBUFFERS_ASSERT(table_object_size < 0x10000);
1103  WriteScalar<voffset_t>(buf_.data() + sizeof(voffset_t),
1104  static_cast<voffset_t>(table_object_size));
1105  WriteScalar<voffset_t>(buf_.data(), max_voffset_);
1106  // Write the offsets into the table
1107  for (auto it = buf_.scratch_end() - num_field_loc * sizeof(FieldLoc);
1108  it < buf_.scratch_end(); it += sizeof(FieldLoc)) {
1109  auto field_location = reinterpret_cast<FieldLoc *>(it);
1110  auto pos = static_cast<voffset_t>(vtableoffsetloc - field_location->off);
1111  // If this asserts, it means you've set a field twice.
1112  FLATBUFFERS_ASSERT(
1113  !ReadScalar<voffset_t>(buf_.data() + field_location->id));
1114  WriteScalar<voffset_t>(buf_.data() + field_location->id, pos);
1115  }
1116  ClearOffsets();
1117  auto vt1 = reinterpret_cast<voffset_t *>(buf_.data());
1118  auto vt1_size = ReadScalar<voffset_t>(vt1);
1119  auto vt_use = GetSize();
1120  // See if we already have generated a vtable with this exact same
1121  // layout before. If so, make it point to the old one, remove this one.
1122  if (dedup_vtables_) {
1123  for (auto it = buf_.scratch_data(); it < buf_.scratch_end();
1124  it += sizeof(uoffset_t)) {
1125  auto vt_offset_ptr = reinterpret_cast<uoffset_t *>(it);
1126  auto vt2 = reinterpret_cast<voffset_t *>(buf_.data_at(*vt_offset_ptr));
1127  auto vt2_size = *vt2;
1128  if (vt1_size != vt2_size || memcmp(vt2, vt1, vt1_size)) continue;
1129  vt_use = *vt_offset_ptr;
1130  buf_.pop(GetSize() - vtableoffsetloc);
1131  break;
1132  }
1133  }
1134  // If this is a new vtable, remember it.
1135  if (vt_use == GetSize()) { buf_.scratch_push_small(vt_use); }
1136  // Fill the vtable offset we created above.
1137  // The offset points from the beginning of the object to where the
1138  // vtable is stored.
1139  // Offsets default direction is downward in memory for future format
1140  // flexibility (storing all vtables at the start of the file).
1141  WriteScalar(buf_.data_at(vtableoffsetloc),
1142  static_cast<soffset_t>(vt_use) -
1143  static_cast<soffset_t>(vtableoffsetloc));
1144 
1145  nested = false;
1146  return vtableoffsetloc;
1147  }
1148 
1149  // DEPRECATED: call the version above instead.
1150  uoffset_t EndTable(uoffset_t start, voffset_t /*numfields*/) {
1151  return EndTable(start);
1152  }
1153 
1154  // This checks a required field has been set in a given table that has
1155  // just been constructed.
1156  template<typename T> void Required(Offset<T> table, voffset_t field);
1157 
1158  uoffset_t StartStruct(size_t alignment) {
1159  Align(alignment);
1160  return GetSize();
1161  }
1162 
1163  uoffset_t EndStruct() { return GetSize(); }
1164 
1165  void ClearOffsets() {
1166  buf_.scratch_pop(num_field_loc * sizeof(FieldLoc));
1167  num_field_loc = 0;
1168  max_voffset_ = 0;
1169  }
1170 
1171  // Aligns such that when "len" bytes are written, an object can be written
1172  // after it with "alignment" without padding.
1173  void PreAlign(size_t len, size_t alignment) {
1174  TrackMinAlign(alignment);
1175  buf_.fill(PaddingBytes(GetSize() + len, alignment));
1176  }
1177  template<typename T> void PreAlign(size_t len) {
1178  AssertScalarT<T>();
1179  PreAlign(len, sizeof(T));
1180  }
1181  /// @endcond
1182 
1183  /// @brief Store a string in the buffer, which can contain any binary data.
1184  /// @param[in] str A const char pointer to the data to be stored as a string.
1185  /// @param[in] len The number of bytes that should be stored from `str`.
1186  /// @return Returns the offset in the buffer where the string starts.
1187  Offset<String> CreateString(const char *str, size_t len) {
1188  NotNested();
1189  PreAlign<uoffset_t>(len + 1); // Always 0-terminated.
1190  buf_.fill(1);
1191  PushBytes(reinterpret_cast<const uint8_t *>(str), len);
1192  PushElement(static_cast<uoffset_t>(len));
1193  return Offset<String>(GetSize());
1194  }
1195 
1196  /// @brief Store a string in the buffer, which is null-terminated.
1197  /// @param[in] str A const char pointer to a C-string to add to the buffer.
1198  /// @return Returns the offset in the buffer where the string starts.
1199  Offset<String> CreateString(const char *str) {
1200  return CreateString(str, strlen(str));
1201  }
1202 
1203  /// @brief Store a string in the buffer, which is null-terminated.
1204  /// @param[in] str A char pointer to a C-string to add to the buffer.
1205  /// @return Returns the offset in the buffer where the string starts.
1207  return CreateString(str, strlen(str));
1208  }
1209 
1210  /// @brief Store a string in the buffer, which can contain any binary data.
1211  /// @param[in] str A const reference to a std::string to store in the buffer.
1212  /// @return Returns the offset in the buffer where the string starts.
1213  Offset<String> CreateString(const std::string &str) {
1214  return CreateString(str.c_str(), str.length());
1215  }
1216 
1217  // clang-format off
1218  #ifdef FLATBUFFERS_HAS_STRING_VIEW
1219  /// @brief Store a string in the buffer, which can contain any binary data.
1220  /// @param[in] str A const string_view to copy in to the buffer.
1221  /// @return Returns the offset in the buffer where the string starts.
1222  Offset<String> CreateString(flatbuffers::string_view str) {
1223  return CreateString(str.data(), str.size());
1224  }
1225  #endif // FLATBUFFERS_HAS_STRING_VIEW
1226  // clang-format on
1227 
1228  /// @brief Store a string in the buffer, which can contain any binary data.
1229  /// @param[in] str A const pointer to a `String` struct to add to the buffer.
1230  /// @return Returns the offset in the buffer where the string starts
1232  return str ? CreateString(str->c_str(), str->Length()) : 0;
1233  }
1234 
1235  /// @brief Store a string in the buffer, which can contain any binary data.
1236  /// @param[in] str A const reference to a std::string like type with support
1237  /// of T::c_str() and T::length() to store in the buffer.
1238  /// @return Returns the offset in the buffer where the string starts.
1239  template<typename T> Offset<String> CreateString(const T &str) {
1240  return CreateString(str.c_str(), str.length());
1241  }
1242 
1243  /// @brief Store a string in the buffer, which can contain any binary data.
1244  /// If a string with this exact contents has already been serialized before,
1245  /// instead simply returns the offset of the existing string.
1246  /// @param[in] str A const char pointer to the data to be stored as a string.
1247  /// @param[in] len The number of bytes that should be stored from `str`.
1248  /// @return Returns the offset in the buffer where the string starts.
1249  Offset<String> CreateSharedString(const char *str, size_t len) {
1250  if (!string_pool)
1251  string_pool = new StringOffsetMap(StringOffsetCompare(buf_));
1252  auto size_before_string = buf_.size();
1253  // Must first serialize the string, since the set is all offsets into
1254  // buffer.
1255  auto off = CreateString(str, len);
1256  auto it = string_pool->find(off);
1257  // If it exists we reuse existing serialized data!
1258  if (it != string_pool->end()) {
1259  // We can remove the string we serialized.
1260  buf_.pop(buf_.size() - size_before_string);
1261  return *it;
1262  }
1263  // Record this string for future use.
1264  string_pool->insert(off);
1265  return off;
1266  }
1267 
1268  /// @brief Store a string in the buffer, which null-terminated.
1269  /// If a string with this exact contents has already been serialized before,
1270  /// instead simply returns the offset of the existing string.
1271  /// @param[in] str A const char pointer to a C-string to add to the buffer.
1272  /// @return Returns the offset in the buffer where the string starts.
1274  return CreateSharedString(str, strlen(str));
1275  }
1276 
1277  /// @brief Store a string in the buffer, which can contain any binary data.
1278  /// If a string with this exact contents has already been serialized before,
1279  /// instead simply returns the offset of the existing string.
1280  /// @param[in] str A const reference to a std::string to store in the buffer.
1281  /// @return Returns the offset in the buffer where the string starts.
1282  Offset<String> CreateSharedString(const std::string &str) {
1283  return CreateSharedString(str.c_str(), str.length());
1284  }
1285 
1286  /// @brief Store a string in the buffer, which can contain any binary data.
1287  /// If a string with this exact contents has already been serialized before,
1288  /// instead simply returns the offset of the existing string.
1289  /// @param[in] str A const pointer to a `String` struct to add to the buffer.
1290  /// @return Returns the offset in the buffer where the string starts
1292  return CreateSharedString(str->c_str(), str->Length());
1293  }
1294 
1295  /// @cond FLATBUFFERS_INTERNAL
1296  uoffset_t EndVector(size_t len) {
1297  FLATBUFFERS_ASSERT(nested); // Hit if no corresponding StartVector.
1298  nested = false;
1299  return PushElement(static_cast<uoffset_t>(len));
1300  }
1301 
1302  void StartVector(size_t len, size_t elemsize) {
1303  NotNested();
1304  nested = true;
1305  PreAlign<uoffset_t>(len * elemsize);
1306  PreAlign(len * elemsize, elemsize); // Just in case elemsize > uoffset_t.
1307  }
1308 
1309  // Call this right before StartVector/CreateVector if you want to force the
1310  // alignment to be something different than what the element size would
1311  // normally dictate.
1312  // This is useful when storing a nested_flatbuffer in a vector of bytes,
1313  // or when storing SIMD floats, etc.
1314  void ForceVectorAlignment(size_t len, size_t elemsize, size_t alignment) {
1315  PreAlign(len * elemsize, alignment);
1316  }
1317 
1318  // Similar to ForceVectorAlignment but for String fields.
1319  void ForceStringAlignment(size_t len, size_t alignment) {
1320  PreAlign((len + 1) * sizeof(char), alignment);
1321  }
1322 
1323  /// @endcond
1324 
1325  /// @brief Serialize an array into a FlatBuffer `vector`.
1326  /// @tparam T The data type of the array elements.
1327  /// @param[in] v A pointer to the array of type `T` to serialize into the
1328  /// buffer as a `vector`.
1329  /// @param[in] len The number of elements to serialize.
1330  /// @return Returns a typed `Offset` into the serialized data indicating
1331  /// where the vector is stored.
1332  template<typename T> Offset<Vector<T>> CreateVector(const T *v, size_t len) {
1333  // If this assert hits, you're specifying a template argument that is
1334  // causing the wrong overload to be selected, remove it.
1335  AssertScalarT<T>();
1336  StartVector(len, sizeof(T));
1337  // clang-format off
1338  #if FLATBUFFERS_LITTLEENDIAN
1339  PushBytes(reinterpret_cast<const uint8_t *>(v), len * sizeof(T));
1340  #else
1341  if (sizeof(T) == 1) {
1342  PushBytes(reinterpret_cast<const uint8_t *>(v), len);
1343  } else {
1344  for (auto i = len; i > 0; ) {
1345  PushElement(v[--i]);
1346  }
1347  }
1348  #endif
1349  // clang-format on
1350  return Offset<Vector<T>>(EndVector(len));
1351  }
1352 
1353  template<typename T>
1354  Offset<Vector<Offset<T>>> CreateVector(const Offset<T> *v, size_t len) {
1355  StartVector(len, sizeof(Offset<T>));
1356  for (auto i = len; i > 0;) { PushElement(v[--i]); }
1357  return Offset<Vector<Offset<T>>>(EndVector(len));
1358  }
1359 
1360  /// @brief Serialize a `std::vector` into a FlatBuffer `vector`.
1361  /// @tparam T The data type of the `std::vector` elements.
1362  /// @param v A const reference to the `std::vector` to serialize into the
1363  /// buffer as a `vector`.
1364  /// @return Returns a typed `Offset` into the serialized data indicating
1365  /// where the vector is stored.
1366  template<typename T> Offset<Vector<T>> CreateVector(const std::vector<T> &v) {
1367  return CreateVector(data(v), v.size());
1368  }
1369 
1370  // vector<bool> may be implemented using a bit-set, so we can't access it as
1371  // an array. Instead, read elements manually.
1372  // Background: https://isocpp.org/blog/2012/11/on-vectorbool
1373  Offset<Vector<uint8_t>> CreateVector(const std::vector<bool> &v) {
1374  StartVector(v.size(), sizeof(uint8_t));
1375  for (auto i = v.size(); i > 0;) {
1376  PushElement(static_cast<uint8_t>(v[--i]));
1377  }
1378  return Offset<Vector<uint8_t>>(EndVector(v.size()));
1379  }
1380 
1381  // clang-format off
1382  #ifndef FLATBUFFERS_CPP98_STL
1383  /// @brief Serialize values returned by a function into a FlatBuffer `vector`.
1384  /// This is a convenience function that takes care of iteration for you.
1385  /// @tparam T The data type of the `std::vector` elements.
1386  /// @param f A function that takes the current iteration 0..vector_size-1 and
1387  /// returns any type that you can construct a FlatBuffers vector out of.
1388  /// @return Returns a typed `Offset` into the serialized data indicating
1389  /// where the vector is stored.
1390  template<typename T> Offset<Vector<T>> CreateVector(size_t vector_size,
1391  const std::function<T (size_t i)> &f) {
1392  std::vector<T> elems(vector_size);
1393  for (size_t i = 0; i < vector_size; i++) elems[i] = f(i);
1394  return CreateVector(elems);
1395  }
1396  #endif
1397  // clang-format on
1398 
1399  /// @brief Serialize values returned by a function into a FlatBuffer `vector`.
1400  /// This is a convenience function that takes care of iteration for you.
1401  /// @tparam T The data type of the `std::vector` elements.
1402  /// @param f A function that takes the current iteration 0..vector_size-1,
1403  /// and the state parameter returning any type that you can construct a
1404  /// FlatBuffers vector out of.
1405  /// @param state State passed to f.
1406  /// @return Returns a typed `Offset` into the serialized data indicating
1407  /// where the vector is stored.
1408  template<typename T, typename F, typename S>
1409  Offset<Vector<T>> CreateVector(size_t vector_size, F f, S *state) {
1410  std::vector<T> elems(vector_size);
1411  for (size_t i = 0; i < vector_size; i++) elems[i] = f(i, state);
1412  return CreateVector(elems);
1413  }
1414 
1415  /// @brief Serialize a `std::vector<std::string>` into a FlatBuffer `vector`.
1416  /// This is a convenience function for a common case.
1417  /// @param v A const reference to the `std::vector` to serialize into the
1418  /// buffer as a `vector`.
1419  /// @return Returns a typed `Offset` into the serialized data indicating
1420  /// where the vector is stored.
1422  const std::vector<std::string> &v) {
1423  std::vector<Offset<String>> offsets(v.size());
1424  for (size_t i = 0; i < v.size(); i++) offsets[i] = CreateString(v[i]);
1425  return CreateVector(offsets);
1426  }
1427 
1428  /// @brief Serialize an array of structs into a FlatBuffer `vector`.
1429  /// @tparam T The data type of the struct array elements.
1430  /// @param[in] v A pointer to the array of type `T` to serialize into the
1431  /// buffer as a `vector`.
1432  /// @param[in] len The number of elements to serialize.
1433  /// @return Returns a typed `Offset` into the serialized data indicating
1434  /// where the vector is stored.
1435  template<typename T>
1437  StartVector(len * sizeof(T) / AlignOf<T>(), AlignOf<T>());
1438  PushBytes(reinterpret_cast<const uint8_t *>(v), sizeof(T) * len);
1439  return Offset<Vector<const T *>>(EndVector(len));
1440  }
1441 
1442  /// @brief Serialize an array of native structs into a FlatBuffer `vector`.
1443  /// @tparam T The data type of the struct array elements.
1444  /// @tparam S The data type of the native struct array elements.
1445  /// @param[in] v A pointer to the array of type `S` to serialize into the
1446  /// buffer as a `vector`.
1447  /// @param[in] len The number of elements to serialize.
1448  /// @return Returns a typed `Offset` into the serialized data indicating
1449  /// where the vector is stored.
1450  template<typename T, typename S>
1452  size_t len) {
1453  extern T Pack(const S &);
1454  typedef T (*Pack_t)(const S &);
1455  std::vector<T> vv(len);
1456  std::transform(v, v + len, vv.begin(), *(Pack_t)&Pack);
1457  return CreateVectorOfStructs<T>(vv.data(), vv.size());
1458  }
1459 
1460  // clang-format off
1461  #ifndef FLATBUFFERS_CPP98_STL
1462  /// @brief Serialize an array of structs into a FlatBuffer `vector`.
1463  /// @tparam T The data type of the struct array elements.
1464  /// @param[in] f A function that takes the current iteration 0..vector_size-1
1465  /// and a pointer to the struct that must be filled.
1466  /// @return Returns a typed `Offset` into the serialized data indicating
1467  /// where the vector is stored.
1468  /// This is mostly useful when flatbuffers are generated with mutation
1469  /// accessors.
1471  size_t vector_size, const std::function<void(size_t i, T *)> &filler) {
1472  T* structs = StartVectorOfStructs<T>(vector_size);
1473  for (size_t i = 0; i < vector_size; i++) {
1474  filler(i, structs);
1475  structs++;
1476  }
1477  return EndVectorOfStructs<T>(vector_size);
1478  }
1479  #endif
1480  // clang-format on
1481 
1482  /// @brief Serialize an array of structs into a FlatBuffer `vector`.
1483  /// @tparam T The data type of the struct array elements.
1484  /// @param[in] f A function that takes the current iteration 0..vector_size-1,
1485  /// a pointer to the struct that must be filled and the state argument.
1486  /// @param[in] state Arbitrary state to pass to f.
1487  /// @return Returns a typed `Offset` into the serialized data indicating
1488  /// where the vector is stored.
1489  /// This is mostly useful when flatbuffers are generated with mutation
1490  /// accessors.
1491  template<typename T, typename F, typename S>
1493  S *state) {
1494  T *structs = StartVectorOfStructs<T>(vector_size);
1495  for (size_t i = 0; i < vector_size; i++) {
1496  f(i, structs, state);
1497  structs++;
1498  }
1499  return EndVectorOfStructs<T>(vector_size);
1500  }
1501 
1502  /// @brief Serialize a `std::vector` of structs into a FlatBuffer `vector`.
1503  /// @tparam T The data type of the `std::vector` struct elements.
1504  /// @param[in]] v A const reference to the `std::vector` of structs to
1505  /// serialize into the buffer as a `vector`.
1506  /// @return Returns a typed `Offset` into the serialized data indicating
1507  /// where the vector is stored.
1508  template<typename T, typename Alloc>
1510  const std::vector<T, Alloc> &v) {
1511  return CreateVectorOfStructs(data(v), v.size());
1512  }
1513 
1514  /// @brief Serialize a `std::vector` of native structs into a FlatBuffer
1515  /// `vector`.
1516  /// @tparam T The data type of the `std::vector` struct elements.
1517  /// @tparam S The data type of the `std::vector` native struct elements.
1518  /// @param[in]] v A const reference to the `std::vector` of structs to
1519  /// serialize into the buffer as a `vector`.
1520  /// @return Returns a typed `Offset` into the serialized data indicating
1521  /// where the vector is stored.
1522  template<typename T, typename S>
1524  const std::vector<S> &v) {
1525  return CreateVectorOfNativeStructs<T, S>(data(v), v.size());
1526  }
1527 
1528  /// @cond FLATBUFFERS_INTERNAL
1529  template<typename T> struct StructKeyComparator {
1530  bool operator()(const T &a, const T &b) const {
1531  return a.KeyCompareLessThan(&b);
1532  }
1533 
1534  private:
1535  StructKeyComparator &operator=(const StructKeyComparator &);
1536  };
1537  /// @endcond
1538 
1539  /// @brief Serialize a `std::vector` of structs into a FlatBuffer `vector`
1540  /// in sorted order.
1541  /// @tparam T The data type of the `std::vector` struct elements.
1542  /// @param[in]] v A const reference to the `std::vector` of structs to
1543  /// serialize into the buffer as a `vector`.
1544  /// @return Returns a typed `Offset` into the serialized data indicating
1545  /// where the vector is stored.
1546  template<typename T>
1548  return CreateVectorOfSortedStructs(data(*v), v->size());
1549  }
1550 
1551  /// @brief Serialize a `std::vector` of native structs into a FlatBuffer
1552  /// `vector` in sorted order.
1553  /// @tparam T The data type of the `std::vector` struct elements.
1554  /// @tparam S The data type of the `std::vector` native struct elements.
1555  /// @param[in]] v A const reference to the `std::vector` of structs to
1556  /// serialize into the buffer as a `vector`.
1557  /// @return Returns a typed `Offset` into the serialized data indicating
1558  /// where the vector is stored.
1559  template<typename T, typename S>
1561  std::vector<S> *v) {
1562  return CreateVectorOfSortedNativeStructs<T, S>(data(*v), v->size());
1563  }
1564 
1565  /// @brief Serialize an array of structs into a FlatBuffer `vector` in sorted
1566  /// order.
1567  /// @tparam T The data type of the struct array elements.
1568  /// @param[in] v A pointer to the array of type `T` to serialize into the
1569  /// buffer as a `vector`.
1570  /// @param[in] len The number of elements to serialize.
1571  /// @return Returns a typed `Offset` into the serialized data indicating
1572  /// where the vector is stored.
1573  template<typename T>
1575  std::sort(v, v + len, StructKeyComparator<T>());
1576  return CreateVectorOfStructs(v, len);
1577  }
1578 
1579  /// @brief Serialize an array of native structs into a FlatBuffer `vector` in
1580  /// sorted order.
1581  /// @tparam T The data type of the struct array elements.
1582  /// @tparam S The data type of the native struct array elements.
1583  /// @param[in] v A pointer to the array of type `S` to serialize into the
1584  /// buffer as a `vector`.
1585  /// @param[in] len The number of elements to serialize.
1586  /// @return Returns a typed `Offset` into the serialized data indicating
1587  /// where the vector is stored.
1588  template<typename T, typename S>
1590  size_t len) {
1591  extern T Pack(const S &);
1592  typedef T (*Pack_t)(const S &);
1593  std::vector<T> vv(len);
1594  std::transform(v, v + len, vv.begin(), *(Pack_t)&Pack);
1595  return CreateVectorOfSortedStructs<T>(vv, len);
1596  }
1597 
1598  /// @cond FLATBUFFERS_INTERNAL
1599  template<typename T> struct TableKeyComparator {
1600  TableKeyComparator(vector_downward &buf) : buf_(buf) {}
1601  bool operator()(const Offset<T> &a, const Offset<T> &b) const {
1602  auto table_a = reinterpret_cast<T *>(buf_.data_at(a.o));
1603  auto table_b = reinterpret_cast<T *>(buf_.data_at(b.o));
1604  return table_a->KeyCompareLessThan(table_b);
1605  }
1606  vector_downward &buf_;
1607 
1608  private:
1609  TableKeyComparator &operator=(const TableKeyComparator &);
1610  };
1611  /// @endcond
1612 
1613  /// @brief Serialize an array of `table` offsets as a `vector` in the buffer
1614  /// in sorted order.
1615  /// @tparam T The data type that the offset refers to.
1616  /// @param[in] v An array of type `Offset<T>` that contains the `table`
1617  /// offsets to store in the buffer in sorted order.
1618  /// @param[in] len The number of elements to store in the `vector`.
1619  /// @return Returns a typed `Offset` into the serialized data indicating
1620  /// where the vector is stored.
1621  template<typename T>
1623  size_t len) {
1624  std::sort(v, v + len, TableKeyComparator<T>(buf_));
1625  return CreateVector(v, len);
1626  }
1627 
1628  /// @brief Serialize an array of `table` offsets as a `vector` in the buffer
1629  /// in sorted order.
1630  /// @tparam T The data type that the offset refers to.
1631  /// @param[in] v An array of type `Offset<T>` that contains the `table`
1632  /// offsets to store in the buffer in sorted order.
1633  /// @return Returns a typed `Offset` into the serialized data indicating
1634  /// where the vector is stored.
1635  template<typename T>
1637  std::vector<Offset<T>> *v) {
1638  return CreateVectorOfSortedTables(data(*v), v->size());
1639  }
1640 
1641  /// @brief Specialized version of `CreateVector` for non-copying use cases.
1642  /// Write the data any time later to the returned buffer pointer `buf`.
1643  /// @param[in] len The number of elements to store in the `vector`.
1644  /// @param[in] elemsize The size of each element in the `vector`.
1645  /// @param[out] buf A pointer to a `uint8_t` pointer that can be
1646  /// written to at a later time to serialize the data into a `vector`
1647  /// in the buffer.
1648  uoffset_t CreateUninitializedVector(size_t len, size_t elemsize,
1649  uint8_t **buf) {
1650  NotNested();
1651  StartVector(len, elemsize);
1652  buf_.make_space(len * elemsize);
1653  auto vec_start = GetSize();
1654  auto vec_end = EndVector(len);
1655  *buf = buf_.data_at(vec_start);
1656  return vec_end;
1657  }
1658 
1659  /// @brief Specialized version of `CreateVector` for non-copying use cases.
1660  /// Write the data any time later to the returned buffer pointer `buf`.
1661  /// @tparam T The data type of the data that will be stored in the buffer
1662  /// as a `vector`.
1663  /// @param[in] len The number of elements to store in the `vector`.
1664  /// @param[out] buf A pointer to a pointer of type `T` that can be
1665  /// written to at a later time to serialize the data into a `vector`
1666  /// in the buffer.
1667  template<typename T>
1669  AssertScalarT<T>();
1670  return CreateUninitializedVector(len, sizeof(T),
1671  reinterpret_cast<uint8_t **>(buf));
1672  }
1673 
1674  template<typename T>
1675  Offset<Vector<const T*>> CreateUninitializedVectorOfStructs(size_t len, T **buf) {
1676  return CreateUninitializedVector(len, sizeof(T),
1677  reinterpret_cast<uint8_t **>(buf));
1678  }
1679 
1680  /// @brief Write a struct by itself, typically to be part of a union.
1681  template<typename T> Offset<const T *> CreateStruct(const T &structobj) {
1682  NotNested();
1683  Align(AlignOf<T>());
1684  buf_.push_small(structobj);
1685  return Offset<const T *>(GetSize());
1686  }
1687 
1688  /// @brief The length of a FlatBuffer file header.
1689  static const size_t kFileIdentifierLength = 4;
1690 
1691  /// @brief Finish serializing a buffer by writing the root offset.
1692  /// @param[in] file_identifier If a `file_identifier` is given, the buffer
1693  /// will be prefixed with a standard FlatBuffers file header.
1694  template<typename T>
1695  void Finish(Offset<T> root, const char *file_identifier = nullptr) {
1696  Finish(root.o, file_identifier, false);
1697  }
1698 
1699  /// @brief Finish a buffer with a 32 bit size field pre-fixed (size of the
1700  /// buffer following the size field). These buffers are NOT compatible
1701  /// with standard buffers created by Finish, i.e. you can't call GetRoot
1702  /// on them, you have to use GetSizePrefixedRoot instead.
1703  /// All >32 bit quantities in this buffer will be aligned when the whole
1704  /// size pre-fixed buffer is aligned.
1705  /// These kinds of buffers are useful for creating a stream of FlatBuffers.
1706  template<typename T>
1708  const char *file_identifier = nullptr) {
1709  Finish(root.o, file_identifier, true);
1710  }
1711 
1712  protected:
1713  // You shouldn't really be copying instances of this class.
1715  FlatBufferBuilder &operator=(const FlatBufferBuilder &);
1716 
1717  void Finish(uoffset_t root, const char *file_identifier, bool size_prefix) {
1718  NotNested();
1719  buf_.clear_scratch();
1720  // This will cause the whole buffer to be aligned.
1721  PreAlign((size_prefix ? sizeof(uoffset_t) : 0) + sizeof(uoffset_t) +
1722  (file_identifier ? kFileIdentifierLength : 0),
1723  minalign_);
1724  if (file_identifier) {
1725  FLATBUFFERS_ASSERT(strlen(file_identifier) == kFileIdentifierLength);
1726  PushBytes(reinterpret_cast<const uint8_t *>(file_identifier),
1727  kFileIdentifierLength);
1728  }
1729  PushElement(ReferTo(root)); // Location of root.
1730  if (size_prefix) { PushElement(GetSize()); }
1731  finished = true;
1732  }
1733 
1734  struct FieldLoc {
1735  uoffset_t off;
1736  voffset_t id;
1737  };
1738 
1739  vector_downward buf_;
1740 
1741  // Accumulating offsets of table members while it is being built.
1742  // We store these in the scratch pad of buf_, after the vtable offsets.
1743  uoffset_t num_field_loc;
1744  // Track how much of the vtable is in use, so we can output the most compact
1745  // possible vtable.
1746  voffset_t max_voffset_;
1747 
1748  // Ensure objects are not nested.
1749  bool nested;
1750 
1751  // Ensure the buffer is finished before it is being accessed.
1752  bool finished;
1753 
1754  size_t minalign_;
1755 
1756  bool force_defaults_; // Serialize values equal to their defaults anyway.
1757 
1758  bool dedup_vtables_;
1759 
1761  StringOffsetCompare(const vector_downward &buf) : buf_(&buf) {}
1762  bool operator()(const Offset<String> &a, const Offset<String> &b) const {
1763  auto stra = reinterpret_cast<const String *>(buf_->data_at(a.o));
1764  auto strb = reinterpret_cast<const String *>(buf_->data_at(b.o));
1765  return strncmp(stra->c_str(), strb->c_str(),
1766  (std::min)(stra->size(), strb->size()) + 1) < 0;
1767  }
1768  const vector_downward *buf_;
1769  };
1770 
1771  // For use with CreateSharedString. Instantiated on first use only.
1772  typedef std::set<Offset<String>, StringOffsetCompare> StringOffsetMap;
1773  StringOffsetMap *string_pool;
1774 
1775  private:
1776  // Allocates space for a vector of structures.
1777  // Must be completed with EndVectorOfStructs().
1778  template<typename T> T *StartVectorOfStructs(size_t vector_size) {
1779  StartVector(vector_size * sizeof(T) / AlignOf<T>(), AlignOf<T>());
1780  return reinterpret_cast<T *>(buf_.make_space(vector_size * sizeof(T)));
1781  }
1782 
1783  // End the vector of structues in the flatbuffers.
1784  // Vector should have previously be started with StartVectorOfStructs().
1785  template<typename T>
1786  Offset<Vector<const T *>> EndVectorOfStructs(size_t vector_size) {
1787  return Offset<Vector<const T *>>(EndVector(vector_size));
1788  }
1789 };
1790 /// @}
1791 
1792 /// @cond FLATBUFFERS_INTERNAL
1793 // Helpers to get a typed pointer to the root object contained in the buffer.
1794 template<typename T> T *GetMutableRoot(void *buf) {
1795  EndianCheck();
1796  return reinterpret_cast<T *>(
1797  reinterpret_cast<uint8_t *>(buf) +
1798  EndianScalar(*reinterpret_cast<uoffset_t *>(buf)));
1799 }
1800 
1801 template<typename T> const T *GetRoot(const void *buf) {
1802  return GetMutableRoot<T>(const_cast<void *>(buf));
1803 }
1804 
1805 template<typename T> const T *GetSizePrefixedRoot(const void *buf) {
1806  return GetRoot<T>(reinterpret_cast<const uint8_t *>(buf) + sizeof(uoffset_t));
1807 }
1808 
1809 /// Helpers to get a typed pointer to objects that are currently being built.
1810 /// @warning Creating new objects will lead to reallocations and invalidates
1811 /// the pointer!
1812 template<typename T>
1813 T *GetMutableTemporaryPointer(FlatBufferBuilder &fbb, Offset<T> offset) {
1814  return reinterpret_cast<T *>(fbb.GetCurrentBufferPointer() + fbb.GetSize() -
1815  offset.o);
1816 }
1817 
1818 template<typename T>
1819 const T *GetTemporaryPointer(FlatBufferBuilder &fbb, Offset<T> offset) {
1820  return GetMutableTemporaryPointer<T>(fbb, offset);
1821 }
1822 
1823 /// @brief Get a pointer to the the file_identifier section of the buffer.
1824 /// @return Returns a const char pointer to the start of the file_identifier
1825 /// characters in the buffer. The returned char * has length
1826 /// 'flatbuffers::FlatBufferBuilder::kFileIdentifierLength'.
1827 /// This function is UNDEFINED for FlatBuffers whose schema does not include
1828 /// a file_identifier (likely points at padding or the start of a the root
1829 /// vtable).
1830 inline const char *GetBufferIdentifier(const void *buf, bool size_prefixed = false) {
1831  return reinterpret_cast<const char *>(buf) +
1832  ((size_prefixed) ? 2 * sizeof(uoffset_t) : sizeof(uoffset_t));
1833 }
1834 
1835 // Helper to see if the identifier in a buffer has the expected value.
1836 inline bool BufferHasIdentifier(const void *buf, const char *identifier, bool size_prefixed = false) {
1837  return strncmp(GetBufferIdentifier(buf, size_prefixed), identifier,
1839 }
1840 
1841 // Helper class to verify the integrity of a FlatBuffer
1842 class Verifier FLATBUFFERS_FINAL_CLASS {
1843  public:
1844  Verifier(const uint8_t *buf, size_t buf_len, uoffset_t _max_depth = 64,
1845  uoffset_t _max_tables = 1000000)
1846  : buf_(buf),
1847  size_(buf_len),
1848  depth_(0),
1849  max_depth_(_max_depth),
1850  num_tables_(0),
1851  max_tables_(_max_tables)
1852  // clang-format off
1853  #ifdef FLATBUFFERS_TRACK_VERIFIER_BUFFER_SIZE
1854  , upper_bound_(0)
1855  #endif
1856  // clang-format on
1857  {
1858  assert(size_ < FLATBUFFERS_MAX_BUFFER_SIZE);
1859  }
1860 
1861  // Central location where any verification failures register.
1862  bool Check(bool ok) const {
1863  // clang-format off
1864  #ifdef FLATBUFFERS_DEBUG_VERIFICATION_FAILURE
1865  FLATBUFFERS_ASSERT(ok);
1866  #endif
1867  #ifdef FLATBUFFERS_TRACK_VERIFIER_BUFFER_SIZE
1868  if (!ok)
1869  upper_bound_ = 0;
1870  #endif
1871  // clang-format on
1872  return ok;
1873  }
1874 
1875  // Verify any range within the buffer.
1876  bool Verify(size_t elem, size_t elem_len) const {
1877  // clang-format off
1878  #ifdef FLATBUFFERS_TRACK_VERIFIER_BUFFER_SIZE
1879  auto upper_bound = elem + elem_len;
1880  if (upper_bound_ < upper_bound)
1881  upper_bound_ = upper_bound;
1882  #endif
1883  // clang-format on
1884  return Check(elem_len < size_ && elem <= size_ - elem_len);
1885  }
1886 
1887  template<typename T> bool VerifyAlignment(size_t elem) const {
1888  return (elem & (sizeof(T) - 1)) == 0;
1889  }
1890 
1891  // Verify a range indicated by sizeof(T).
1892  template<typename T> bool Verify(size_t elem) const {
1893  return VerifyAlignment<T>(elem) && Verify(elem, sizeof(T));
1894  }
1895 
1896  // Verify relative to a known-good base pointer.
1897  bool Verify(const uint8_t *base, voffset_t elem_off, size_t elem_len) const {
1898  return Verify(static_cast<size_t>(base - buf_) + elem_off, elem_len);
1899  }
1900 
1901  template<typename T> bool Verify(const uint8_t *base, voffset_t elem_off)
1902  const {
1903  return Verify(static_cast<size_t>(base - buf_) + elem_off, sizeof(T));
1904  }
1905 
1906  // Verify a pointer (may be NULL) of a table type.
1907  template<typename T> bool VerifyTable(const T *table) {
1908  return !table || table->Verify(*this);
1909  }
1910 
1911  // Verify a pointer (may be NULL) of any vector type.
1912  template<typename T> bool VerifyVector(const Vector<T> *vec) const {
1913  return !vec || VerifyVectorOrString(reinterpret_cast<const uint8_t *>(vec),
1914  sizeof(T));
1915  }
1916 
1917  // Verify a pointer (may be NULL) of a vector to struct.
1918  template<typename T> bool VerifyVector(const Vector<const T *> *vec) const {
1919  return VerifyVector(reinterpret_cast<const Vector<T> *>(vec));
1920  }
1921 
1922  // Verify a pointer (may be NULL) to string.
1923  bool VerifyString(const String *str) const {
1924  size_t end;
1925  return !str ||
1926  (VerifyVectorOrString(reinterpret_cast<const uint8_t *>(str),
1927  1, &end) &&
1928  Verify(end, 1) && // Must have terminator
1929  Check(buf_[end] == '\0')); // Terminating byte must be 0.
1930  }
1931 
1932  // Common code between vectors and strings.
1933  bool VerifyVectorOrString(const uint8_t *vec, size_t elem_size,
1934  size_t *end = nullptr) const {
1935  auto veco = static_cast<size_t>(vec - buf_);
1936  // Check we can read the size field.
1937  if (!Verify<uoffset_t>(veco)) return false;
1938  // Check the whole array. If this is a string, the byte past the array
1939  // must be 0.
1940  auto size = ReadScalar<uoffset_t>(vec);
1941  auto max_elems = FLATBUFFERS_MAX_BUFFER_SIZE / elem_size;
1942  if (!Check(size < max_elems))
1943  return false; // Protect against byte_size overflowing.
1944  auto byte_size = sizeof(size) + elem_size * size;
1945  if (end) *end = veco + byte_size;
1946  return Verify(veco, byte_size);
1947  }
1948 
1949  // Special case for string contents, after the above has been called.
1950  bool VerifyVectorOfStrings(const Vector<Offset<String>> *vec) const {
1951  if (vec) {
1952  for (uoffset_t i = 0; i < vec->size(); i++) {
1953  if (!VerifyString(vec->Get(i))) return false;
1954  }
1955  }
1956  return true;
1957  }
1958 
1959  // Special case for table contents, after the above has been called.
1960  template<typename T> bool VerifyVectorOfTables(const Vector<Offset<T>> *vec) {
1961  if (vec) {
1962  for (uoffset_t i = 0; i < vec->size(); i++) {
1963  if (!vec->Get(i)->Verify(*this)) return false;
1964  }
1965  }
1966  return true;
1967  }
1968 
1969  bool VerifyTableStart(const uint8_t *table) {
1970  // Check the vtable offset.
1971  auto tableo = static_cast<size_t>(table - buf_);
1972  if (!Verify<soffset_t>(tableo)) return false;
1973  // This offset may be signed, but doing the substraction unsigned always
1974  // gives the result we want.
1975  auto vtableo = tableo - static_cast<size_t>(ReadScalar<soffset_t>(table));
1976  // Check the vtable size field, then check vtable fits in its entirety.
1977  return VerifyComplexity() && Verify<voffset_t>(vtableo) &&
1978  VerifyAlignment<voffset_t>(ReadScalar<voffset_t>(buf_ + vtableo)) &&
1979  Verify(vtableo, ReadScalar<voffset_t>(buf_ + vtableo));
1980  }
1981 
1982  template<typename T>
1983  bool VerifyBufferFromStart(const char *identifier, size_t start) {
1984  if (identifier &&
1985  (size_ < 2 * sizeof(flatbuffers::uoffset_t) ||
1986  !BufferHasIdentifier(buf_ + start, identifier))) {
1987  return false;
1988  }
1989 
1990  // Call T::Verify, which must be in the generated code for this type.
1991  auto o = VerifyOffset(start);
1992  return o && reinterpret_cast<const T *>(buf_ + start + o)->Verify(*this)
1993  // clang-format off
1994  #ifdef FLATBUFFERS_TRACK_VERIFIER_BUFFER_SIZE
1995  && GetComputedSize()
1996  #endif
1997  ;
1998  // clang-format on
1999  }
2000 
2001  // Verify this whole buffer, starting with root type T.
2002  template<typename T> bool VerifyBuffer() { return VerifyBuffer<T>(nullptr); }
2003 
2004  template<typename T> bool VerifyBuffer(const char *identifier) {
2005  return VerifyBufferFromStart<T>(identifier, 0);
2006  }
2007 
2008  template<typename T> bool VerifySizePrefixedBuffer(const char *identifier) {
2009  return Verify<uoffset_t>(0U) &&
2010  ReadScalar<uoffset_t>(buf_) == size_ - sizeof(uoffset_t) &&
2011  VerifyBufferFromStart<T>(identifier, sizeof(uoffset_t));
2012  }
2013 
2014  uoffset_t VerifyOffset(size_t start) const {
2015  if (!Verify<uoffset_t>(start)) return 0;
2016  auto o = ReadScalar<uoffset_t>(buf_ + start);
2017  // May not point to itself.
2018  Check(o != 0);
2019  // Can't wrap around / buffers are max 2GB.
2020  if (!Check(static_cast<soffset_t>(o) >= 0)) return 0;
2021  // Must be inside the buffer to create a pointer from it (pointer outside
2022  // buffer is UB).
2023  if (!Verify(start + o, 1)) return 0;
2024  return o;
2025  }
2026 
2027  uoffset_t VerifyOffset(const uint8_t *base, voffset_t start) const {
2028  return VerifyOffset(static_cast<size_t>(base - buf_) + start);
2029  }
2030 
2031  // Called at the start of a table to increase counters measuring data
2032  // structure depth and amount, and possibly bails out with false if
2033  // limits set by the constructor have been hit. Needs to be balanced
2034  // with EndTable().
2035  bool VerifyComplexity() {
2036  depth_++;
2037  num_tables_++;
2038  return Check(depth_ <= max_depth_ && num_tables_ <= max_tables_);
2039  }
2040 
2041  // Called at the end of a table to pop the depth count.
2042  bool EndTable() {
2043  depth_--;
2044  return true;
2045  }
2046 
2047  // clang-format off
2048  #ifdef FLATBUFFERS_TRACK_VERIFIER_BUFFER_SIZE
2049  // Returns the message size in bytes
2050  size_t GetComputedSize() const {
2051  uintptr_t size = upper_bound_;
2052  // Align the size to uoffset_t
2053  size = (size - 1 + sizeof(uoffset_t)) & ~(sizeof(uoffset_t) - 1);
2054  return (size > size_) ? 0 : size;
2055  }
2056  #endif
2057  // clang-format on
2058 
2059  private:
2060  const uint8_t *buf_;
2061  size_t size_;
2062  uoffset_t depth_;
2063  uoffset_t max_depth_;
2064  uoffset_t num_tables_;
2065  uoffset_t max_tables_;
2066  // clang-format off
2067  #ifdef FLATBUFFERS_TRACK_VERIFIER_BUFFER_SIZE
2068  mutable size_t upper_bound_;
2069  #endif
2070  // clang-format on
2071 };
2072 
2073 // Convenient way to bundle a buffer and its length, to pass it around
2074 // typed by its root.
2075 // A BufferRef does not own its buffer.
2076 struct BufferRefBase {}; // for std::is_base_of
2077 template<typename T> struct BufferRef : BufferRefBase {
2078  BufferRef() : buf(nullptr), len(0), must_free(false) {}
2079  BufferRef(uint8_t *_buf, uoffset_t _len)
2080  : buf(_buf), len(_len), must_free(false) {}
2081 
2082  ~BufferRef() {
2083  if (must_free) free(buf);
2084  }
2085 
2086  const T *GetRoot() const { return flatbuffers::GetRoot<T>(buf); }
2087 
2088  bool Verify() {
2089  Verifier verifier(buf, len);
2090  return verifier.VerifyBuffer<T>(nullptr);
2091  }
2092 
2093  uint8_t *buf;
2094  uoffset_t len;
2095  bool must_free;
2096 };
2097 
2098 // "structs" are flat structures that do not have an offset table, thus
2099 // always have all members present and do not support forwards/backwards
2100 // compatible extensions.
2101 
2102 class Struct FLATBUFFERS_FINAL_CLASS {
2103  public:
2104  template<typename T> T GetField(uoffset_t o) const {
2105  return ReadScalar<T>(&data_[o]);
2106  }
2107 
2108  template<typename T> T GetStruct(uoffset_t o) const {
2109  return reinterpret_cast<T>(&data_[o]);
2110  }
2111 
2112  const uint8_t *GetAddressOf(uoffset_t o) const { return &data_[o]; }
2113  uint8_t *GetAddressOf(uoffset_t o) { return &data_[o]; }
2114 
2115  private:
2116  uint8_t data_[1];
2117 };
2118 
2119 // "tables" use an offset table (possibly shared) that allows fields to be
2120 // omitted and added at will, but uses an extra indirection to read.
2121 class Table {
2122  public:
2123  const uint8_t *GetVTable() const {
2124  return data_ - ReadScalar<soffset_t>(data_);
2125  }
2126 
2127  // This gets the field offset for any of the functions below it, or 0
2128  // if the field was not present.
2129  voffset_t GetOptionalFieldOffset(voffset_t field) const {
2130  // The vtable offset is always at the start.
2131  auto vtable = GetVTable();
2132  // The first element is the size of the vtable (fields + type id + itself).
2133  auto vtsize = ReadScalar<voffset_t>(vtable);
2134  // If the field we're accessing is outside the vtable, we're reading older
2135  // data, so it's the same as if the offset was 0 (not present).
2136  return field < vtsize ? ReadScalar<voffset_t>(vtable + field) : 0;
2137  }
2138 
2139  template<typename T> T GetField(voffset_t field, T defaultval) const {
2140  auto field_offset = GetOptionalFieldOffset(field);
2141  return field_offset ? ReadScalar<T>(data_ + field_offset) : defaultval;
2142  }
2143 
2144  template<typename P> P GetPointer(voffset_t field) {
2145  auto field_offset = GetOptionalFieldOffset(field);
2146  auto p = data_ + field_offset;
2147  return field_offset ? reinterpret_cast<P>(p + ReadScalar<uoffset_t>(p))
2148  : nullptr;
2149  }
2150  template<typename P> P GetPointer(voffset_t field) const {
2151  return const_cast<Table *>(this)->GetPointer<P>(field);
2152  }
2153 
2154  template<typename P> P GetStruct(voffset_t field) const {
2155  auto field_offset = GetOptionalFieldOffset(field);
2156  auto p = const_cast<uint8_t *>(data_ + field_offset);
2157  return field_offset ? reinterpret_cast<P>(p) : nullptr;
2158  }
2159 
2160  template<typename T> bool SetField(voffset_t field, T val, T def) {
2161  auto field_offset = GetOptionalFieldOffset(field);
2162  if (!field_offset) return val == def;
2163  WriteScalar(data_ + field_offset, val);
2164  return true;
2165  }
2166 
2167  bool SetPointer(voffset_t field, const uint8_t *val) {
2168  auto field_offset = GetOptionalFieldOffset(field);
2169  if (!field_offset) return false;
2170  WriteScalar(data_ + field_offset,
2171  static_cast<uoffset_t>(val - (data_ + field_offset)));
2172  return true;
2173  }
2174 
2175  uint8_t *GetAddressOf(voffset_t field) {
2176  auto field_offset = GetOptionalFieldOffset(field);
2177  return field_offset ? data_ + field_offset : nullptr;
2178  }
2179  const uint8_t *GetAddressOf(voffset_t field) const {
2180  return const_cast<Table *>(this)->GetAddressOf(field);
2181  }
2182 
2183  bool CheckField(voffset_t field) const {
2184  return GetOptionalFieldOffset(field) != 0;
2185  }
2186 
2187  // Verify the vtable of this table.
2188  // Call this once per table, followed by VerifyField once per field.
2189  bool VerifyTableStart(Verifier &verifier) const {
2190  return verifier.VerifyTableStart(data_);
2191  }
2192 
2193  // Verify a particular field.
2194  template<typename T>
2195  bool VerifyField(const Verifier &verifier, voffset_t field) const {
2196  // Calling GetOptionalFieldOffset should be safe now thanks to
2197  // VerifyTable().
2198  auto field_offset = GetOptionalFieldOffset(field);
2199  // Check the actual field.
2200  return !field_offset || verifier.Verify<T>(data_, field_offset);
2201  }
2202 
2203  // VerifyField for required fields.
2204  template<typename T>
2205  bool VerifyFieldRequired(const Verifier &verifier, voffset_t field) const {
2206  auto field_offset = GetOptionalFieldOffset(field);
2207  return verifier.Check(field_offset != 0) &&
2208  verifier.Verify<T>(data_, field_offset);
2209  }
2210 
2211  // Versions for offsets.
2212  bool VerifyOffset(const Verifier &verifier, voffset_t field) const {
2213  auto field_offset = GetOptionalFieldOffset(field);
2214  return !field_offset || verifier.VerifyOffset(data_, field_offset);
2215  }
2216 
2217  bool VerifyOffsetRequired(const Verifier &verifier, voffset_t field) const {
2218  auto field_offset = GetOptionalFieldOffset(field);
2219  return verifier.Check(field_offset != 0) &&
2220  verifier.VerifyOffset(data_, field_offset);
2221  }
2222 
2223  private:
2224  // private constructor & copy constructor: you obtain instances of this
2225  // class by pointing to existing data only
2226  Table();
2227  Table(const Table &other);
2228 
2229  uint8_t data_[1];
2230 };
2231 
2232 template<typename T> void FlatBufferBuilder::Required(Offset<T> table,
2233  voffset_t field) {
2234  auto table_ptr = reinterpret_cast<const Table *>(buf_.data_at(table.o));
2235  bool ok = table_ptr->GetOptionalFieldOffset(field) != 0;
2236  // If this fails, the caller will show what field needs to be set.
2237  FLATBUFFERS_ASSERT(ok);
2238  (void)ok;
2239 }
2240 
2241 /// @brief This can compute the start of a FlatBuffer from a root pointer, i.e.
2242 /// it is the opposite transformation of GetRoot().
2243 /// This may be useful if you want to pass on a root and have the recipient
2244 /// delete the buffer afterwards.
2245 inline const uint8_t *GetBufferStartFromRootPointer(const void *root) {
2246  auto table = reinterpret_cast<const Table *>(root);
2247  auto vtable = table->GetVTable();
2248  // Either the vtable is before the root or after the root.
2249  auto start = (std::min)(vtable, reinterpret_cast<const uint8_t *>(root));
2250  // Align to at least sizeof(uoffset_t).
2251  start = reinterpret_cast<const uint8_t *>(reinterpret_cast<uintptr_t>(start) &
2252  ~(sizeof(uoffset_t) - 1));
2253  // Additionally, there may be a file_identifier in the buffer, and the root
2254  // offset. The buffer may have been aligned to any size between
2255  // sizeof(uoffset_t) and FLATBUFFERS_MAX_ALIGNMENT (see "force_align").
2256  // Sadly, the exact alignment is only known when constructing the buffer,
2257  // since it depends on the presence of values with said alignment properties.
2258  // So instead, we simply look at the next uoffset_t values (root,
2259  // file_identifier, and alignment padding) to see which points to the root.
2260  // None of the other values can "impersonate" the root since they will either
2261  // be 0 or four ASCII characters.
2262  static_assert(FlatBufferBuilder::kFileIdentifierLength == sizeof(uoffset_t),
2263  "file_identifier is assumed to be the same size as uoffset_t");
2264  for (auto possible_roots = FLATBUFFERS_MAX_ALIGNMENT / sizeof(uoffset_t) + 1;
2265  possible_roots; possible_roots--) {
2266  start -= sizeof(uoffset_t);
2267  if (ReadScalar<uoffset_t>(start) + start ==
2268  reinterpret_cast<const uint8_t *>(root))
2269  return start;
2270  }
2271  // We didn't find the root, either the "root" passed isn't really a root,
2272  // or the buffer is corrupt.
2273  // Assert, because calling this function with bad data may cause reads
2274  // outside of buffer boundaries.
2275  FLATBUFFERS_ASSERT(false);
2276  return nullptr;
2277 }
2278 
2279 /// @brief This return the prefixed size of a FlatBuffer.
2280 inline uoffset_t GetPrefixedSize(const uint8_t* buf){ return ReadScalar<uoffset_t>(buf); }
2281 
2282 // Base class for native objects (FlatBuffer data de-serialized into native
2283 // C++ data structures).
2284 // Contains no functionality, purely documentative.
2285 struct NativeTable {};
2286 
2287 /// @brief Function types to be used with resolving hashes into objects and
2288 /// back again. The resolver gets a pointer to a field inside an object API
2289 /// object that is of the type specified in the schema using the attribute
2290 /// `cpp_type` (it is thus important whatever you write to this address
2291 /// matches that type). The value of this field is initially null, so you
2292 /// may choose to implement a delayed binding lookup using this function
2293 /// if you wish. The resolver does the opposite lookup, for when the object
2294 /// is being serialized again.
2295 typedef uint64_t hash_value_t;
2296 // clang-format off
2297 #ifdef FLATBUFFERS_CPP98_STL
2298  typedef void (*resolver_function_t)(void **pointer_adr, hash_value_t hash);
2299  typedef hash_value_t (*rehasher_function_t)(void *pointer);
2300 #else
2301  typedef std::function<void (void **pointer_adr, hash_value_t hash)>
2302  resolver_function_t;
2303  typedef std::function<hash_value_t (void *pointer)> rehasher_function_t;
2304 #endif
2305 // clang-format on
2306 
2307 // Helper function to test if a field is present, using any of the field
2308 // enums in the generated code.
2309 // `table` must be a generated table type. Since this is a template parameter,
2310 // this is not typechecked to be a subclass of Table, so beware!
2311 // Note: this function will return false for fields equal to the default
2312 // value, since they're not stored in the buffer (unless force_defaults was
2313 // used).
2314 template<typename T> bool IsFieldPresent(const T *table, voffset_t field) {
2315  // Cast, since Table is a private baseclass of any table types.
2316  return reinterpret_cast<const Table *>(table)->CheckField(field);
2317 }
2318 
2319 // Utility function for reverse lookups on the EnumNames*() functions
2320 // (in the generated C++ code)
2321 // names must be NULL terminated.
2322 inline int LookupEnum(const char **names, const char *name) {
2323  for (const char **p = names; *p; p++)
2324  if (!strcmp(*p, name)) return static_cast<int>(p - names);
2325  return -1;
2326 }
2327 
2328 // These macros allow us to layout a struct with a guarantee that they'll end
2329 // up looking the same on different compilers and platforms.
2330 // It does this by disallowing the compiler to do any padding, and then
2331 // does padding itself by inserting extra padding fields that make every
2332 // element aligned to its own size.
2333 // Additionally, it manually sets the alignment of the struct as a whole,
2334 // which is typically its largest element, or a custom size set in the schema
2335 // by the force_align attribute.
2336 // These are used in the generated code only.
2337 
2338 // clang-format off
2339 #if defined(_MSC_VER)
2340  #define FLATBUFFERS_MANUALLY_ALIGNED_STRUCT(alignment) \
2341  __pragma(pack(1)); \
2342  struct __declspec(align(alignment))
2343  #define FLATBUFFERS_STRUCT_END(name, size) \
2344  __pragma(pack()); \
2345  static_assert(sizeof(name) == size, "compiler breaks packing rules")
2346 #elif defined(__GNUC__) || defined(__clang__)
2347  #define FLATBUFFERS_MANUALLY_ALIGNED_STRUCT(alignment) \
2348  _Pragma("pack(1)") \
2349  struct __attribute__((aligned(alignment)))
2350  #define FLATBUFFERS_STRUCT_END(name, size) \
2351  _Pragma("pack()") \
2352  static_assert(sizeof(name) == size, "compiler breaks packing rules")
2353 #else
2354  #error Unknown compiler, please define structure alignment macros
2355 #endif
2356 // clang-format on
2357 
2358 // Minimal reflection via code generation.
2359 // Besides full-fat reflection (see reflection.h) and parsing/printing by
2360 // loading schemas (see idl.h), we can also have code generation for mimimal
2361 // reflection data which allows pretty-printing and other uses without needing
2362 // a schema or a parser.
2363 // Generate code with --reflect-types (types only) or --reflect-names (names
2364 // also) to enable.
2365 // See minireflect.h for utilities using this functionality.
2366 
2367 // These types are organized slightly differently as the ones in idl.h.
2368 enum SequenceType { ST_TABLE, ST_STRUCT, ST_UNION, ST_ENUM };
2369 
2370 // Scalars have the same order as in idl.h
2371 // clang-format off
2372 #define FLATBUFFERS_GEN_ELEMENTARY_TYPES(ET) \
2373  ET(ET_UTYPE) \
2374  ET(ET_BOOL) \
2375  ET(ET_CHAR) \
2376  ET(ET_UCHAR) \
2377  ET(ET_SHORT) \
2378  ET(ET_USHORT) \
2379  ET(ET_INT) \
2380  ET(ET_UINT) \
2381  ET(ET_LONG) \
2382  ET(ET_ULONG) \
2383  ET(ET_FLOAT) \
2384  ET(ET_DOUBLE) \
2385  ET(ET_STRING) \
2386  ET(ET_SEQUENCE) // See SequenceType.
2387 
2388 enum ElementaryType {
2389  #define FLATBUFFERS_ET(E) E,
2390  FLATBUFFERS_GEN_ELEMENTARY_TYPES(FLATBUFFERS_ET)
2391  #undef FLATBUFFERS_ET
2392 };
2393 
2394 inline const char * const *ElementaryTypeNames() {
2395  static const char * const names[] = {
2396  #define FLATBUFFERS_ET(E) #E,
2397  FLATBUFFERS_GEN_ELEMENTARY_TYPES(FLATBUFFERS_ET)
2398  #undef FLATBUFFERS_ET
2399  };
2400  return names;
2401 }
2402 // clang-format on
2403 
2404 // Basic type info cost just 16bits per field!
2405 struct TypeCode {
2406  uint16_t base_type : 4; // ElementaryType
2407  uint16_t is_vector : 1;
2408  int16_t sequence_ref : 11; // Index into type_refs below, or -1 for none.
2409 };
2410 
2411 static_assert(sizeof(TypeCode) == 2, "TypeCode");
2412 
2413 struct TypeTable;
2414 
2415 // Signature of the static method present in each type.
2416 typedef const TypeTable *(*TypeFunction)();
2417 
2418 struct TypeTable {
2419  SequenceType st;
2420  size_t num_elems; // of type_codes, values, names (but not type_refs).
2421  const TypeCode *type_codes; // num_elems count
2422  const TypeFunction *type_refs; // less than num_elems entries (see TypeCode).
2423  const int32_t *values; // Only set for non-consecutive enum/union or structs.
2424  const char * const *names; // Only set if compiled with --reflect-names.
2425 };
2426 
2427 // String which identifies the current version of FlatBuffers.
2428 // flatbuffer_version_string is used by Google developers to identify which
2429 // applications uploaded to Google Play are using this library. This allows
2430 // the development team at Google to determine the popularity of the library.
2431 // How it works: Applications that are uploaded to the Google Play Store are
2432 // scanned for this version string. We track which applications are using it
2433 // to measure popularity. You are free to remove it (of course) but we would
2434 // appreciate if you left it in.
2435 
2436 // Weak linkage is culled by VS & doesn't work on cygwin.
2437 // clang-format off
2438 #if !defined(_WIN32) && !defined(__CYGWIN__)
2439 
2440 extern volatile __attribute__((weak)) const char *flatbuffer_version_string;
2441 volatile __attribute__((weak)) const char *flatbuffer_version_string =
2442  "FlatBuffers "
2443  FLATBUFFERS_STRING(FLATBUFFERS_VERSION_MAJOR) "."
2444  FLATBUFFERS_STRING(FLATBUFFERS_VERSION_MINOR) "."
2445  FLATBUFFERS_STRING(FLATBUFFERS_VERSION_REVISION);
2446 
2447 #endif // !defined(_WIN32) && !defined(__CYGWIN__)
2448 
2449 #define FLATBUFFERS_DEFINE_BITMASK_OPERATORS(E, T)\
2450  inline E operator | (E lhs, E rhs){\
2451  return E(T(lhs) | T(rhs));\
2452  }\
2453  inline E operator & (E lhs, E rhs){\
2454  return E(T(lhs) & T(rhs));\
2455  }\
2456  inline E operator ^ (E lhs, E rhs){\
2457  return E(T(lhs) ^ T(rhs));\
2458  }\
2459  inline E operator ~ (E lhs){\
2460  return E(~T(lhs));\
2461  }\
2462  inline E operator |= (E &lhs, E rhs){\
2463  lhs = lhs | rhs;\
2464  return lhs;\
2465  }\
2466  inline E operator &= (E &lhs, E rhs){\
2467  lhs = lhs & rhs;\
2468  return lhs;\
2469  }\
2470  inline E operator ^= (E &lhs, E rhs){\
2471  lhs = lhs ^ rhs;\
2472  return lhs;\
2473  }\
2474  inline bool operator !(E rhs) \
2475  {\
2476  return !bool(T(rhs)); \
2477  }
2478 /// @endcond
2479 } // namespace flatbuffers
2480 
2481 #if defined(_MSC_VER)
2482  #pragma warning(pop)
2483 #endif
2484 // clang-format on
2485 
2486 #endif // FLATBUFFERS_H_
Definition: flatbuffers.h:25
Offset< Vector< T > > CreateVector(size_t vector_size, const std::function< T(size_t i)> &f)
Serialize values returned by a function into a FlatBuffer vector.
Definition: flatbuffers.h:1390
uoffset_t CreateUninitializedVector(size_t len, size_t elemsize, uint8_t **buf)
Specialized version of CreateVector for non-copying use cases.
Definition: flatbuffers.h:1648
Offset< Vector< const T * > > CreateVectorOfStructs(size_t vector_size, const std::function< void(size_t i, T *)> &filler)
Serialize an array of structs into a FlatBuffer vector.
Definition: flatbuffers.h:1470
Offset< Vector< const T * > > CreateVectorOfSortedStructs(T *v, size_t len)
Serialize an array of structs into a FlatBuffer vector in sorted order.
Definition: flatbuffers.h:1574
Offset< Vector< const T * > > CreateVectorOfSortedNativeStructs(std::vector< S > *v)
Serialize a std::vector of native structs into a FlatBuffer vector in sorted order.
Definition: flatbuffers.h:1560
uoffset_t GetSize() const
The current size of the serialized buffer, counting from the end.
Definition: flatbuffers.h:901
Offset< Vector< Offset< T > > > CreateVectorOfSortedTables(std::vector< Offset< T >> *v)
Serialize an array of table offsets as a vector in the buffer in sorted order.
Definition: flatbuffers.h:1636
Definition: flatbuffers.h:91
Helper class to hold data needed in creation of a FlatBuffer.
Definition: flatbuffers.h:811
FlatBufferBuilder & operator=(FlatBufferBuilder &&other)
Move assignment operator for FlatBufferBuilder.
Definition: flatbuffers.h:859
Offset< String > CreateString(char *str)
Store a string in the buffer, which is null-terminated.
Definition: flatbuffers.h:1206
void Clear()
Reset all the state in this FlatBufferBuilder so it can be reused to construct another buffer...
Definition: flatbuffers.h:890
Offset< Vector< const T * > > CreateVectorOfStructs(size_t vector_size, F f, S *state)
Serialize an array of structs into a FlatBuffer vector.
Definition: flatbuffers.h:1492
Offset< Vector< const T * > > CreateVectorOfNativeStructs(const S *v, size_t len)
Serialize an array of native structs into a FlatBuffer vector.
Definition: flatbuffers.h:1451
Offset< const T * > CreateStruct(const T &structobj)
Write a struct by itself, typically to be part of a union.
Definition: flatbuffers.h:1681
Definition: flatbuffers.h:22
void FinishSizePrefixed(Offset< T > root, const char *file_identifier=nullptr)
Finish a buffer with a 32 bit size field pre-fixed (size of the buffer following the size field)...
Definition: flatbuffers.h:1707
Definition: flatbuffers.h:453
Offset< String > CreateSharedString(const char *str)
Store a string in the buffer, which null-terminated.
Definition: flatbuffers.h:1273
Definition: flatbuffers.h:305
FlatBufferBuilder(FlatBufferBuilder &&other)
Move constructor for FlatBufferBuilder.
Definition: flatbuffers.h:842
Definition: flatbuffers.h:63
Offset< String > CreateString(const char *str, size_t len)
Store a string in the buffer, which can contain any binary data.
Definition: flatbuffers.h:1187
void ForceDefaults(bool fd)
In order to save space, fields that are set to their default value don&#39;t get serialized into the buff...
Definition: flatbuffers.h:970
uint8_t * GetBufferPointer() const
Get the serialized buffer (after you call Finish()).
Definition: flatbuffers.h:906
Definition: flatbuffers.h:415
void DedupVtables(bool dedup)
By default vtables are deduped in order to save space.
Definition: flatbuffers.h:974
static const size_t kFileIdentifierLength
The length of a FlatBuffer file header.
Definition: flatbuffers.h:1689
FlatBufferBuilder(size_t initial_size=1024, Allocator *allocator=nullptr, bool own_allocator=false, size_t buffer_minalign=AlignOf< largest_scalar_t >())
Default constructor for FlatBufferBuilder.
Definition: flatbuffers.h:824
Offset< String > CreateString(const String *str)
Store a string in the buffer, which can contain any binary data.
Definition: flatbuffers.h:1231
Definition: flatbuffers.h:560
Offset< Vector< const T * > > CreateVectorOfSortedNativeStructs(S *v, size_t len)
Serialize an array of native structs into a FlatBuffer vector in sorted order.
Definition: flatbuffers.h:1589
Offset< String > CreateSharedString(const String *str)
Store a string in the buffer, which can contain any binary data.
Definition: flatbuffers.h:1291
uint8_t * GetCurrentBufferPointer() const
Get a pointer to an unfinished buffer.
Definition: flatbuffers.h:913
Offset< String > CreateString(const T &str)
Store a string in the buffer, which can contain any binary data.
Definition: flatbuffers.h:1239
Offset< Vector< const T * > > CreateVectorOfSortedStructs(std::vector< T > *v)
Serialize a std::vector of structs into a FlatBuffer vector in sorted order.
Definition: flatbuffers.h:1547
Offset< Vector< Offset< String > > > CreateVectorOfStrings(const std::vector< std::string > &v)
Serialize a std::vector<std::string> into a FlatBuffer vector.
Definition: flatbuffers.h:1421
Offset< Vector< T > > CreateVector(size_t vector_size, F f, S *state)
Serialize values returned by a function into a FlatBuffer vector.
Definition: flatbuffers.h:1409
size_t GetBufferMinAlignment()
get the minimum alignment this buffer needs to be accessed properly.
Definition: flatbuffers.h:950
Offset< Vector< const T * > > CreateVectorOfStructs(const std::vector< T, Alloc > &v)
Serialize a std::vector of structs into a FlatBuffer vector.
Definition: flatbuffers.h:1509
Offset< Vector< const T * > > CreateVectorOfStructs(const T *v, size_t len)
Serialize an array of structs into a FlatBuffer vector.
Definition: flatbuffers.h:1436
Offset< Vector< const T * > > CreateVectorOfNativeStructs(const std::vector< S > &v)
Serialize a std::vector of native structs into a FlatBuffer vector.
Definition: flatbuffers.h:1523
Offset< String > CreateString(const char *str)
Store a string in the buffer, which is null-terminated.
Definition: flatbuffers.h:1199
Definition: flatbuffers.h:374
Definition: flatbuffers.h:343
uint8_t * ReleaseRaw(size_t &size, size_t &offset)
Get the released pointer to the serialized buffer.
Definition: flatbuffers.h:940
Definition: flatbuffers.h:1734
Offset< String > CreateString(const std::string &str)
Store a string in the buffer, which can contain any binary data.
Definition: flatbuffers.h:1213
Offset< Vector< T > > CreateVector(const std::vector< T > &v)
Serialize a std::vector into a FlatBuffer vector.
Definition: flatbuffers.h:1366
Offset< Vector< T > > CreateUninitializedVector(size_t len, T **buf)
Specialized version of CreateVector for non-copying use cases.
Definition: flatbuffers.h:1668
Offset< String > CreateString(flatbuffers::string_view str)
Store a string in the buffer, which can contain any binary data.
Definition: flatbuffers.h:1222
Offset< Vector< T > > CreateVector(const T *v, size_t len)
Serialize an array into a FlatBuffer vector.
Definition: flatbuffers.h:1332
Offset< String > CreateSharedString(const std::string &str)
Store a string in the buffer, which can contain any binary data.
Definition: flatbuffers.h:1282
Offset< Vector< Offset< T > > > CreateVectorOfSortedTables(Offset< T > *v, size_t len)
Serialize an array of table offsets as a vector in the buffer in sorted order.
Definition: flatbuffers.h:1622
DetachedBuffer Release()
Get the released DetachedBuffer.
Definition: flatbuffers.h:927
Offset< String > CreateSharedString(const char *str, size_t len)
Store a string in the buffer, which can contain any binary data.
Definition: flatbuffers.h:1249
Definition: flatbuffers.h:182
DetachedBuffer ReleaseBufferPointer()
Get the released pointer to the serialized buffer.
Definition: flatbuffers.h:920
void Finish(Offset< T > root, const char *file_identifier=nullptr)
Finish serializing a buffer by writing the root offset.
Definition: flatbuffers.h:1695