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diff --git a/executor/_include/flatbuffers/flatbuffer_builder.h b/executor/_include/flatbuffers/flatbuffer_builder.h new file mode 100644 index 000000000..f9432338f --- /dev/null +++ b/executor/_include/flatbuffers/flatbuffer_builder.h @@ -0,0 +1,1214 @@ +/* + * Copyright 2021 Google Inc. All rights reserved. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#ifndef FLATBUFFERS_FLATBUFFER_BUILDER_H_ +#define FLATBUFFERS_FLATBUFFER_BUILDER_H_ + +#include <functional> +#include <initializer_list> + +#include "flatbuffers/allocator.h" +#include "flatbuffers/array.h" +#include "flatbuffers/base.h" +#include "flatbuffers/buffer_ref.h" +#include "flatbuffers/default_allocator.h" +#include "flatbuffers/detached_buffer.h" +#include "flatbuffers/stl_emulation.h" +#include "flatbuffers/string.h" +#include "flatbuffers/struct.h" +#include "flatbuffers/table.h" +#include "flatbuffers/vector.h" +#include "flatbuffers/vector_downward.h" +#include "flatbuffers/verifier.h" + +namespace flatbuffers { + +// Converts a Field ID to a virtual table offset. +inline voffset_t FieldIndexToOffset(voffset_t field_id) { + // Should correspond to what EndTable() below builds up. + const int fixed_fields = 2; // Vtable size and Object Size. + return static_cast<voffset_t>((field_id + fixed_fields) * sizeof(voffset_t)); +} + +template<typename T, typename Alloc = std::allocator<T>> +const T *data(const std::vector<T, Alloc> &v) { + // Eventually the returned pointer gets passed down to memcpy, so + // we need it to be non-null to avoid undefined behavior. + static uint8_t t; + return v.empty() ? reinterpret_cast<const T *>(&t) : &v.front(); +} +template<typename T, typename Alloc = std::allocator<T>> +T *data(std::vector<T, Alloc> &v) { + // Eventually the returned pointer gets passed down to memcpy, so + // we need it to be non-null to avoid undefined behavior. + static uint8_t t; + return v.empty() ? reinterpret_cast<T *>(&t) : &v.front(); +} + +/// @addtogroup flatbuffers_cpp_api +/// @{ +/// @class FlatBufferBuilder +/// @brief Helper class to hold data needed in creation of a FlatBuffer. +/// To serialize data, you typically call one of the `Create*()` functions in +/// the generated code, which in turn call a sequence of `StartTable`/ +/// `PushElement`/`AddElement`/`EndTable`, or the builtin `CreateString`/ +/// `CreateVector` functions. Do this is depth-first order to build up a tree to +/// the root. `Finish()` wraps up the buffer ready for transport. +class FlatBufferBuilder { + public: + /// @brief Default constructor for FlatBufferBuilder. + /// @param[in] initial_size The initial size of the buffer, in bytes. Defaults + /// to `1024`. + /// @param[in] allocator An `Allocator` to use. If null will use + /// `DefaultAllocator`. + /// @param[in] own_allocator Whether the builder/vector should own the + /// allocator. Defaults to / `false`. + /// @param[in] buffer_minalign Force the buffer to be aligned to the given + /// minimum alignment upon reallocation. Only needed if you intend to store + /// types with custom alignment AND you wish to read the buffer in-place + /// directly after creation. + explicit FlatBufferBuilder( + size_t initial_size = 1024, Allocator *allocator = nullptr, + bool own_allocator = false, + size_t buffer_minalign = AlignOf<largest_scalar_t>()) + : buf_(initial_size, allocator, own_allocator, buffer_minalign), + num_field_loc(0), + max_voffset_(0), + nested(false), + finished(false), + minalign_(1), + force_defaults_(false), + dedup_vtables_(true), + string_pool(nullptr) { + EndianCheck(); + } + + /// @brief Move constructor for FlatBufferBuilder. + FlatBufferBuilder(FlatBufferBuilder &&other) + : buf_(1024, nullptr, false, AlignOf<largest_scalar_t>()), + num_field_loc(0), + max_voffset_(0), + nested(false), + finished(false), + minalign_(1), + force_defaults_(false), + dedup_vtables_(true), + string_pool(nullptr) { + EndianCheck(); + // Default construct and swap idiom. + // Lack of delegating constructors in vs2010 makes it more verbose than + // needed. + Swap(other); + } + + /// @brief Move assignment operator for FlatBufferBuilder. + FlatBufferBuilder &operator=(FlatBufferBuilder &&other) { + // Move construct a temporary and swap idiom + FlatBufferBuilder temp(std::move(other)); + Swap(temp); + return *this; + } + + void Swap(FlatBufferBuilder &other) { + using std::swap; + buf_.swap(other.buf_); + swap(num_field_loc, other.num_field_loc); + swap(max_voffset_, other.max_voffset_); + swap(nested, other.nested); + swap(finished, other.finished); + swap(minalign_, other.minalign_); + swap(force_defaults_, other.force_defaults_); + swap(dedup_vtables_, other.dedup_vtables_); + swap(string_pool, other.string_pool); + } + + ~FlatBufferBuilder() { + if (string_pool) delete string_pool; + } + + void Reset() { + Clear(); // clear builder state + buf_.reset(); // deallocate buffer + } + + /// @brief Reset all the state in this FlatBufferBuilder so it can be reused + /// to construct another buffer. + void Clear() { + ClearOffsets(); + buf_.clear(); + nested = false; + finished = false; + minalign_ = 1; + if (string_pool) string_pool->clear(); + } + + /// @brief The current size of the serialized buffer, counting from the end. + /// @return Returns an `uoffset_t` with the current size of the buffer. + uoffset_t GetSize() const { return buf_.size(); } + + /// @brief Get the serialized buffer (after you call `Finish()`). + /// @return Returns an `uint8_t` pointer to the FlatBuffer data inside the + /// buffer. + uint8_t *GetBufferPointer() const { + Finished(); + return buf_.data(); + } + + /// @brief Get the serialized buffer (after you call `Finish()`) as a span. + /// @return Returns a constructed flatbuffers::span that is a view over the + /// FlatBuffer data inside the buffer. + flatbuffers::span<uint8_t> GetBufferSpan() const { + Finished(); + return flatbuffers::span<uint8_t>(buf_.data(), buf_.size()); + } + + /// @brief Get a pointer to an unfinished buffer. + /// @return Returns a `uint8_t` pointer to the unfinished buffer. + uint8_t *GetCurrentBufferPointer() const { return buf_.data(); } + + /// @brief Get the released pointer to the serialized buffer. + /// @warning Do NOT attempt to use this FlatBufferBuilder afterwards! + /// @return A `FlatBuffer` that owns the buffer and its allocator and + /// behaves similar to a `unique_ptr` with a deleter. + FLATBUFFERS_ATTRIBUTE([[deprecated("use Release() instead")]]) + DetachedBuffer ReleaseBufferPointer() { + Finished(); + return buf_.release(); + } + + /// @brief Get the released DetachedBuffer. + /// @return A `DetachedBuffer` that owns the buffer and its allocator. + DetachedBuffer Release() { + Finished(); + return buf_.release(); + } + + /// @brief Get the released pointer to the serialized buffer. + /// @param size The size of the memory block containing + /// the serialized `FlatBuffer`. + /// @param offset The offset from the released pointer where the finished + /// `FlatBuffer` starts. + /// @return A raw pointer to the start of the memory block containing + /// the serialized `FlatBuffer`. + /// @remark If the allocator is owned, it gets deleted when the destructor is + /// called.. + uint8_t *ReleaseRaw(size_t &size, size_t &offset) { + Finished(); + return buf_.release_raw(size, offset); + } + + /// @brief get the minimum alignment this buffer needs to be accessed + /// properly. This is only known once all elements have been written (after + /// you call Finish()). You can use this information if you need to embed + /// a FlatBuffer in some other buffer, such that you can later read it + /// without first having to copy it into its own buffer. + size_t GetBufferMinAlignment() const { + Finished(); + return minalign_; + } + + /// @cond FLATBUFFERS_INTERNAL + void Finished() const { + // If you get this assert, you're attempting to get access a buffer + // which hasn't been finished yet. Be sure to call + // FlatBufferBuilder::Finish with your root table. + // If you really need to access an unfinished buffer, call + // GetCurrentBufferPointer instead. + FLATBUFFERS_ASSERT(finished); + } + /// @endcond + + /// @brief In order to save space, fields that are set to their default value + /// don't get serialized into the buffer. + /// @param[in] fd When set to `true`, always serializes default values that + /// are set. Optional fields which are not set explicitly, will still not be + /// serialized. + void ForceDefaults(bool fd) { force_defaults_ = fd; } + + /// @brief By default vtables are deduped in order to save space. + /// @param[in] dedup When set to `true`, dedup vtables. + void DedupVtables(bool dedup) { dedup_vtables_ = dedup; } + + /// @cond FLATBUFFERS_INTERNAL + void Pad(size_t num_bytes) { buf_.fill(num_bytes); } + + void TrackMinAlign(size_t elem_size) { + if (elem_size > minalign_) minalign_ = elem_size; + } + + void Align(size_t elem_size) { + TrackMinAlign(elem_size); + buf_.fill(PaddingBytes(buf_.size(), elem_size)); + } + + void PushFlatBuffer(const uint8_t *bytes, size_t size) { + PushBytes(bytes, size); + finished = true; + } + + void PushBytes(const uint8_t *bytes, size_t size) { buf_.push(bytes, size); } + + void PopBytes(size_t amount) { buf_.pop(amount); } + + template<typename T> void AssertScalarT() { + // The code assumes power of 2 sizes and endian-swap-ability. + static_assert(flatbuffers::is_scalar<T>::value, "T must be a scalar type"); + } + + // Write a single aligned scalar to the buffer + template<typename T> uoffset_t PushElement(T element) { + AssertScalarT<T>(); + Align(sizeof(T)); + buf_.push_small(EndianScalar(element)); + return GetSize(); + } + + template<typename T> uoffset_t PushElement(Offset<T> off) { + // Special case for offsets: see ReferTo below. + return PushElement(ReferTo(off.o)); + } + + // When writing fields, we track where they are, so we can create correct + // vtables later. + void TrackField(voffset_t field, uoffset_t off) { + FieldLoc fl = { off, field }; + buf_.scratch_push_small(fl); + num_field_loc++; + if (field > max_voffset_) { max_voffset_ = field; } + } + + // Like PushElement, but additionally tracks the field this represents. + template<typename T> void AddElement(voffset_t field, T e, T def) { + // We don't serialize values equal to the default. + if (IsTheSameAs(e, def) && !force_defaults_) return; + TrackField(field, PushElement(e)); + } + + template<typename T> void AddElement(voffset_t field, T e) { + TrackField(field, PushElement(e)); + } + + template<typename T> void AddOffset(voffset_t field, Offset<T> off) { + if (off.IsNull()) return; // Don't store. + AddElement(field, ReferTo(off.o), static_cast<uoffset_t>(0)); + } + + template<typename T> void AddStruct(voffset_t field, const T *structptr) { + if (!structptr) return; // Default, don't store. + Align(AlignOf<T>()); + buf_.push_small(*structptr); + TrackField(field, GetSize()); + } + + void AddStructOffset(voffset_t field, uoffset_t off) { + TrackField(field, off); + } + + // Offsets initially are relative to the end of the buffer (downwards). + // This function converts them to be relative to the current location + // in the buffer (when stored here), pointing upwards. + uoffset_t ReferTo(uoffset_t off) { + // Align to ensure GetSize() below is correct. + Align(sizeof(uoffset_t)); + // Offset must refer to something already in buffer. + const uoffset_t size = GetSize(); + FLATBUFFERS_ASSERT(off && off <= size); + return size - off + static_cast<uoffset_t>(sizeof(uoffset_t)); + } + + void NotNested() { + // If you hit this, you're trying to construct a Table/Vector/String + // during the construction of its parent table (between the MyTableBuilder + // and table.Finish(). + // Move the creation of these sub-objects to above the MyTableBuilder to + // not get this assert. + // Ignoring this assert may appear to work in simple cases, but the reason + // it is here is that storing objects in-line may cause vtable offsets + // to not fit anymore. It also leads to vtable duplication. + FLATBUFFERS_ASSERT(!nested); + // If you hit this, fields were added outside the scope of a table. + FLATBUFFERS_ASSERT(!num_field_loc); + } + + // From generated code (or from the parser), we call StartTable/EndTable + // with a sequence of AddElement calls in between. + uoffset_t StartTable() { + NotNested(); + nested = true; + return GetSize(); + } + + // This finishes one serialized object by generating the vtable if it's a + // table, comparing it against existing vtables, and writing the + // resulting vtable offset. + uoffset_t EndTable(uoffset_t start) { + // If you get this assert, a corresponding StartTable wasn't called. + FLATBUFFERS_ASSERT(nested); + // Write the vtable offset, which is the start of any Table. + // We fill its value later. + auto vtableoffsetloc = PushElement<soffset_t>(0); + // Write a vtable, which consists entirely of voffset_t elements. + // It starts with the number of offsets, followed by a type id, followed + // by the offsets themselves. In reverse: + // Include space for the last offset and ensure empty tables have a + // minimum size. + max_voffset_ = + (std::max)(static_cast<voffset_t>(max_voffset_ + sizeof(voffset_t)), + FieldIndexToOffset(0)); + buf_.fill_big(max_voffset_); + auto table_object_size = vtableoffsetloc - start; + // Vtable use 16bit offsets. + FLATBUFFERS_ASSERT(table_object_size < 0x10000); + WriteScalar<voffset_t>(buf_.data() + sizeof(voffset_t), + static_cast<voffset_t>(table_object_size)); + WriteScalar<voffset_t>(buf_.data(), max_voffset_); + // Write the offsets into the table + for (auto it = buf_.scratch_end() - num_field_loc * sizeof(FieldLoc); + it < buf_.scratch_end(); it += sizeof(FieldLoc)) { + auto field_location = reinterpret_cast<FieldLoc *>(it); + auto pos = static_cast<voffset_t>(vtableoffsetloc - field_location->off); + // If this asserts, it means you've set a field twice. + FLATBUFFERS_ASSERT( + !ReadScalar<voffset_t>(buf_.data() + field_location->id)); + WriteScalar<voffset_t>(buf_.data() + field_location->id, pos); + } + ClearOffsets(); + auto vt1 = reinterpret_cast<voffset_t *>(buf_.data()); + auto vt1_size = ReadScalar<voffset_t>(vt1); + auto vt_use = GetSize(); + // See if we already have generated a vtable with this exact same + // layout before. If so, make it point to the old one, remove this one. + if (dedup_vtables_) { + for (auto it = buf_.scratch_data(); it < buf_.scratch_end(); + it += sizeof(uoffset_t)) { + auto vt_offset_ptr = reinterpret_cast<uoffset_t *>(it); + auto vt2 = reinterpret_cast<voffset_t *>(buf_.data_at(*vt_offset_ptr)); + auto vt2_size = ReadScalar<voffset_t>(vt2); + if (vt1_size != vt2_size || 0 != memcmp(vt2, vt1, vt1_size)) continue; + vt_use = *vt_offset_ptr; + buf_.pop(GetSize() - vtableoffsetloc); + break; + } + } + // If this is a new vtable, remember it. + if (vt_use == GetSize()) { buf_.scratch_push_small(vt_use); } + // Fill the vtable offset we created above. + // The offset points from the beginning of the object to where the + // vtable is stored. + // Offsets default direction is downward in memory for future format + // flexibility (storing all vtables at the start of the file). + WriteScalar(buf_.data_at(vtableoffsetloc), + static_cast<soffset_t>(vt_use) - + static_cast<soffset_t>(vtableoffsetloc)); + + nested = false; + return vtableoffsetloc; + } + + FLATBUFFERS_ATTRIBUTE([[deprecated("call the version above instead")]]) + uoffset_t EndTable(uoffset_t start, voffset_t /*numfields*/) { + return EndTable(start); + } + + // This checks a required field has been set in a given table that has + // just been constructed. + template<typename T> void Required(Offset<T> table, voffset_t field); + + uoffset_t StartStruct(size_t alignment) { + Align(alignment); + return GetSize(); + } + + uoffset_t EndStruct() { return GetSize(); } + + void ClearOffsets() { + buf_.scratch_pop(num_field_loc * sizeof(FieldLoc)); + num_field_loc = 0; + max_voffset_ = 0; + } + + // Aligns such that when "len" bytes are written, an object can be written + // after it with "alignment" without padding. + void PreAlign(size_t len, size_t alignment) { + if (len == 0) return; + TrackMinAlign(alignment); + buf_.fill(PaddingBytes(GetSize() + len, alignment)); + } + template<typename T> void PreAlign(size_t len) { + AssertScalarT<T>(); + PreAlign(len, sizeof(T)); + } + /// @endcond + + /// @brief Store a string in the buffer, which can contain any binary data. + /// @param[in] str A const char pointer to the data to be stored as a string. + /// @param[in] len The number of bytes that should be stored from `str`. + /// @return Returns the offset in the buffer where the string starts. + Offset<String> CreateString(const char *str, size_t len) { + NotNested(); + PreAlign<uoffset_t>(len + 1); // Always 0-terminated. + buf_.fill(1); + PushBytes(reinterpret_cast<const uint8_t *>(str), len); + PushElement(static_cast<uoffset_t>(len)); + return Offset<String>(GetSize()); + } + + /// @brief Store a string in the buffer, which is null-terminated. + /// @param[in] str A const char pointer to a C-string to add to the buffer. + /// @return Returns the offset in the buffer where the string starts. + Offset<String> CreateString(const char *str) { + return CreateString(str, strlen(str)); + } + + /// @brief Store a string in the buffer, which is null-terminated. + /// @param[in] str A char pointer to a C-string to add to the buffer. + /// @return Returns the offset in the buffer where the string starts. + Offset<String> CreateString(char *str) { + return CreateString(str, strlen(str)); + } + + /// @brief Store a string in the buffer, which can contain any binary data. + /// @param[in] str A const reference to a std::string to store in the buffer. + /// @return Returns the offset in the buffer where the string starts. + Offset<String> CreateString(const std::string &str) { + return CreateString(str.c_str(), str.length()); + } + + // clang-format off + #ifdef FLATBUFFERS_HAS_STRING_VIEW + /// @brief Store a string in the buffer, which can contain any binary data. + /// @param[in] str A const string_view to copy in to the buffer. + /// @return Returns the offset in the buffer where the string starts. + Offset<String> CreateString(flatbuffers::string_view str) { + return CreateString(str.data(), str.size()); + } + #endif // FLATBUFFERS_HAS_STRING_VIEW + // clang-format on + + /// @brief Store a string in the buffer, which can contain any binary data. + /// @param[in] str A const pointer to a `String` struct to add to the buffer. + /// @return Returns the offset in the buffer where the string starts + Offset<String> CreateString(const String *str) { + return str ? CreateString(str->c_str(), str->size()) : 0; + } + + /// @brief Store a string in the buffer, which can contain any binary data. + /// @param[in] str A const reference to a std::string like type with support + /// of T::c_str() and T::length() to store in the buffer. + /// @return Returns the offset in the buffer where the string starts. + template<typename T> Offset<String> CreateString(const T &str) { + return CreateString(str.c_str(), str.length()); + } + + /// @brief Store a string in the buffer, which can contain any binary data. + /// If a string with this exact contents has already been serialized before, + /// instead simply returns the offset of the existing string. This uses a map + /// stored on the heap, but only stores the numerical offsets. + /// @param[in] str A const char pointer to the data to be stored as a string. + /// @param[in] len The number of bytes that should be stored from `str`. + /// @return Returns the offset in the buffer where the string starts. + Offset<String> CreateSharedString(const char *str, size_t len) { + FLATBUFFERS_ASSERT(FLATBUFFERS_GENERAL_HEAP_ALLOC_OK); + if (!string_pool) + string_pool = new StringOffsetMap(StringOffsetCompare(buf_)); + auto size_before_string = buf_.size(); + // Must first serialize the string, since the set is all offsets into + // buffer. + auto off = CreateString(str, len); + auto it = string_pool->find(off); + // If it exists we reuse existing serialized data! + if (it != string_pool->end()) { + // We can remove the string we serialized. + buf_.pop(buf_.size() - size_before_string); + return *it; + } + // Record this string for future use. + string_pool->insert(off); + return off; + } + +#ifdef FLATBUFFERS_HAS_STRING_VIEW + /// @brief Store a string in the buffer, which can contain any binary data. + /// If a string with this exact contents has already been serialized before, + /// instead simply returns the offset of the existing string. This uses a map + /// stored on the heap, but only stores the numerical offsets. + /// @param[in] str A const std::string_view to store in the buffer. + /// @return Returns the offset in the buffer where the string starts + Offset<String> CreateSharedString(const flatbuffers::string_view str) { + return CreateSharedString(str.data(), str.size()); + } +#else + /// @brief Store a string in the buffer, which null-terminated. + /// If a string with this exact contents has already been serialized before, + /// instead simply returns the offset of the existing string. This uses a map + /// stored on the heap, but only stores the numerical offsets. + /// @param[in] str A const char pointer to a C-string to add to the buffer. + /// @return Returns the offset in the buffer where the string starts. + Offset<String> CreateSharedString(const char *str) { + return CreateSharedString(str, strlen(str)); + } + + /// @brief Store a string in the buffer, which can contain any binary data. + /// If a string with this exact contents has already been serialized before, + /// instead simply returns the offset of the existing string. This uses a map + /// stored on the heap, but only stores the numerical offsets. + /// @param[in] str A const reference to a std::string to store in the buffer. + /// @return Returns the offset in the buffer where the string starts. + Offset<String> CreateSharedString(const std::string &str) { + return CreateSharedString(str.c_str(), str.length()); + } +#endif + + /// @brief Store a string in the buffer, which can contain any binary data. + /// If a string with this exact contents has already been serialized before, + /// instead simply returns the offset of the existing string. This uses a map + /// stored on the heap, but only stores the numerical offsets. + /// @param[in] str A const pointer to a `String` struct to add to the buffer. + /// @return Returns the offset in the buffer where the string starts + Offset<String> CreateSharedString(const String *str) { + return str ? CreateSharedString(str->c_str(), str->size()) : 0; + } + + /// @cond FLATBUFFERS_INTERNAL + uoffset_t EndVector(size_t len) { + FLATBUFFERS_ASSERT(nested); // Hit if no corresponding StartVector. + nested = false; + return PushElement(static_cast<uoffset_t>(len)); + } + + void StartVector(size_t len, size_t elemsize) { + NotNested(); + nested = true; + PreAlign<uoffset_t>(len * elemsize); + PreAlign(len * elemsize, elemsize); // Just in case elemsize > uoffset_t. + } + + // Call this right before StartVector/CreateVector if you want to force the + // alignment to be something different than what the element size would + // normally dictate. + // This is useful when storing a nested_flatbuffer in a vector of bytes, + // or when storing SIMD floats, etc. + void ForceVectorAlignment(size_t len, size_t elemsize, size_t alignment) { + if (len == 0) return; + FLATBUFFERS_ASSERT(VerifyAlignmentRequirements(alignment)); + PreAlign(len * elemsize, alignment); + } + + // Similar to ForceVectorAlignment but for String fields. + void ForceStringAlignment(size_t len, size_t alignment) { + if (len == 0) return; + FLATBUFFERS_ASSERT(VerifyAlignmentRequirements(alignment)); + PreAlign((len + 1) * sizeof(char), alignment); + } + + /// @endcond + + /// @brief Serialize an array into a FlatBuffer `vector`. + /// @tparam T The data type of the array elements. + /// @param[in] v A pointer to the array of type `T` to serialize into the + /// buffer as a `vector`. + /// @param[in] len The number of elements to serialize. + /// @return Returns a typed `Offset` into the serialized data indicating + /// where the vector is stored. + template<typename T> Offset<Vector<T>> CreateVector(const T *v, size_t len) { + // If this assert hits, you're specifying a template argument that is + // causing the wrong overload to be selected, remove it. + AssertScalarT<T>(); + StartVector(len, sizeof(T)); + if (len == 0) { return Offset<Vector<T>>(EndVector(len)); } + // clang-format off + #if FLATBUFFERS_LITTLEENDIAN + PushBytes(reinterpret_cast<const uint8_t *>(v), len * sizeof(T)); + #else + if (sizeof(T) == 1) { + PushBytes(reinterpret_cast<const uint8_t *>(v), len); + } else { + for (auto i = len; i > 0; ) { + PushElement(v[--i]); + } + } + #endif + // clang-format on + return Offset<Vector<T>>(EndVector(len)); + } + + /// @brief Serialize an array like object into a FlatBuffer `vector`. + /// @tparam T The data type of the array elements. + /// @tparam C The type of the array. + /// @param[in] array A reference to an array like object of type `T` to + /// serialize into the buffer as a `vector`. + /// @return Returns a typed `Offset` into the serialized data indicating + /// where the vector is stored. + template<typename T, class C> Offset<Vector<T>> CreateVector(const C &array) { + return CreateVector(array.data(), array.size()); + } + + /// @brief Serialize an initializer list into a FlatBuffer `vector`. + /// @tparam T The data type of the initializer list elements. + /// @param[in] v The value of the initializer list. + /// @return Returns a typed `Offset` into the serialized data indicating + /// where the vector is stored. + template<typename T> + Offset<Vector<T>> CreateVector(std::initializer_list<T> v) { + return CreateVector(v.begin(), v.size()); + } + + template<typename T> + Offset<Vector<Offset<T>>> CreateVector(const Offset<T> *v, size_t len) { + StartVector(len, sizeof(Offset<T>)); + for (auto i = len; i > 0;) { PushElement(v[--i]); } + return Offset<Vector<Offset<T>>>(EndVector(len)); + } + + /// @brief Serialize a `std::vector` into a FlatBuffer `vector`. + /// @tparam T The data type of the `std::vector` elements. + /// @param v A const reference to the `std::vector` to serialize into the + /// buffer as a `vector`. + /// @return Returns a typed `Offset` into the serialized data indicating + /// where the vector is stored. + template<typename T, typename Alloc = std::allocator<T>> + Offset<Vector<T>> CreateVector(const std::vector<T, Alloc> &v) { + return CreateVector(data(v), v.size()); + } + + // vector<bool> may be implemented using a bit-set, so we can't access it as + // an array. Instead, read elements manually. + // Background: https://isocpp.org/blog/2012/11/on-vectorbool + Offset<Vector<uint8_t>> CreateVector(const std::vector<bool> &v) { + StartVector(v.size(), sizeof(uint8_t)); + for (auto i = v.size(); i > 0;) { + PushElement(static_cast<uint8_t>(v[--i])); + } + return Offset<Vector<uint8_t>>(EndVector(v.size())); + } + + /// @brief Serialize values returned by a function into a FlatBuffer `vector`. + /// This is a convenience function that takes care of iteration for you. + /// @tparam T The data type of the `std::vector` elements. + /// @param f A function that takes the current iteration 0..vector_size-1 and + /// returns any type that you can construct a FlatBuffers vector out of. + /// @return Returns a typed `Offset` into the serialized data indicating + /// where the vector is stored. + template<typename T> + Offset<Vector<T>> CreateVector(size_t vector_size, + const std::function<T(size_t i)> &f) { + FLATBUFFERS_ASSERT(FLATBUFFERS_GENERAL_HEAP_ALLOC_OK); + std::vector<T> elems(vector_size); + for (size_t i = 0; i < vector_size; i++) elems[i] = f(i); + return CreateVector(elems); + } + + /// @brief Serialize values returned by a function into a FlatBuffer `vector`. + /// This is a convenience function that takes care of iteration for you. This + /// uses a vector stored on the heap to store the intermediate results of the + /// iteration. + /// @tparam T The data type of the `std::vector` elements. + /// @param f A function that takes the current iteration 0..vector_size-1, + /// and the state parameter returning any type that you can construct a + /// FlatBuffers vector out of. + /// @param state State passed to f. + /// @return Returns a typed `Offset` into the serialized data indicating + /// where the vector is stored. + template<typename T, typename F, typename S> + Offset<Vector<T>> CreateVector(size_t vector_size, F f, S *state) { + FLATBUFFERS_ASSERT(FLATBUFFERS_GENERAL_HEAP_ALLOC_OK); + std::vector<T> elems(vector_size); + for (size_t i = 0; i < vector_size; i++) elems[i] = f(i, state); + return CreateVector(elems); + } + + /// @brief Serialize a `std::vector<StringType>` into a FlatBuffer `vector`. + /// whereas StringType is any type that is accepted by the CreateString() + /// overloads. + /// This is a convenience function for a common case. + /// @param v A const reference to the `std::vector` to serialize into the + /// buffer as a `vector`. + /// @return Returns a typed `Offset` into the serialized data indicating + /// where the vector is stored. + template<typename StringType = std::string, + typename Alloc = std::allocator<StringType>> + Offset<Vector<Offset<String>>> CreateVectorOfStrings( + const std::vector<StringType, Alloc> &v) { + return CreateVectorOfStrings(v.cbegin(), v.cend()); + } + + /// @brief Serialize a collection of Strings into a FlatBuffer `vector`. + /// This is a convenience function for a common case. + /// @param begin The beginning iterator of the collection + /// @param end The ending iterator of the collection + /// @return Returns a typed `Offset` into the serialized data indicating + /// where the vector is stored. + template<class It> + Offset<Vector<Offset<String>>> CreateVectorOfStrings(It begin, It end) { + auto size = std::distance(begin, end); + auto scratch_buffer_usage = size * sizeof(Offset<String>); + // If there is not enough space to store the offsets, there definitely won't + // be enough space to store all the strings. So ensuring space for the + // scratch region is OK, for if it fails, it would have failed later. + buf_.ensure_space(scratch_buffer_usage); + for (auto it = begin; it != end; ++it) { + buf_.scratch_push_small(CreateString(*it)); + } + StartVector(size, sizeof(Offset<String>)); + for (auto i = 1; i <= size; i++) { + // Note we re-evaluate the buf location each iteration to account for any + // underlying buffer resizing that may occur. + PushElement(*reinterpret_cast<Offset<String> *>( + buf_.scratch_end() - i * sizeof(Offset<String>))); + } + buf_.scratch_pop(scratch_buffer_usage); + return Offset<Vector<Offset<String>>>(EndVector(size)); + } + + /// @brief Serialize an array of structs into a FlatBuffer `vector`. + /// @tparam T The data type of the struct array elements. + /// @param[in] v A pointer to the array of type `T` to serialize into the + /// buffer as a `vector`. + /// @param[in] len The number of elements to serialize. + /// @return Returns a typed `Offset` into the serialized data indicating + /// where the vector is stored. + template<typename T> + Offset<Vector<const T *>> CreateVectorOfStructs(const T *v, size_t len) { + StartVector(len * sizeof(T) / AlignOf<T>(), AlignOf<T>()); + if (len > 0) { + PushBytes(reinterpret_cast<const uint8_t *>(v), sizeof(T) * len); + } + return Offset<Vector<const T *>>(EndVector(len)); + } + + /// @brief Serialize an array of native structs into a FlatBuffer `vector`. + /// @tparam T The data type of the struct array elements. + /// @tparam S The data type of the native struct array elements. + /// @param[in] v A pointer to the array of type `S` to serialize into the + /// buffer as a `vector`. + /// @param[in] len The number of elements to serialize. + /// @param[in] pack_func Pointer to a function to convert the native struct + /// to the FlatBuffer struct. + /// @return Returns a typed `Offset` into the serialized data indicating + /// where the vector is stored. + template<typename T, typename S> + Offset<Vector<const T *>> CreateVectorOfNativeStructs( + const S *v, size_t len, T (*const pack_func)(const S &)) { + FLATBUFFERS_ASSERT(pack_func); + auto structs = StartVectorOfStructs<T>(len); + for (size_t i = 0; i < len; i++) { structs[i] = pack_func(v[i]); } + return EndVectorOfStructs<T>(len); + } + + /// @brief Serialize an array of native structs into a FlatBuffer `vector`. + /// @tparam T The data type of the struct array elements. + /// @tparam S The data type of the native struct array elements. + /// @param[in] v A pointer to the array of type `S` to serialize into the + /// buffer as a `vector`. + /// @param[in] len The number of elements to serialize. + /// @return Returns a typed `Offset` into the serialized data indicating + /// where the vector is stored. + template<typename T, typename S> + Offset<Vector<const T *>> CreateVectorOfNativeStructs(const S *v, + size_t len) { + extern T Pack(const S &); + return CreateVectorOfNativeStructs(v, len, Pack); + } + + /// @brief Serialize an array of structs into a FlatBuffer `vector`. + /// @tparam T The data type of the struct array elements. + /// @param[in] filler A function that takes the current iteration + /// 0..vector_size-1 and a pointer to the struct that must be filled. + /// @return Returns a typed `Offset` into the serialized data indicating + /// where the vector is stored. + /// This is mostly useful when flatbuffers are generated with mutation + /// accessors. + template<typename T> + Offset<Vector<const T *>> CreateVectorOfStructs( + size_t vector_size, const std::function<void(size_t i, T *)> &filler) { + T *structs = StartVectorOfStructs<T>(vector_size); + for (size_t i = 0; i < vector_size; i++) { + filler(i, structs); + structs++; + } + return EndVectorOfStructs<T>(vector_size); + } + + /// @brief Serialize an array of structs into a FlatBuffer `vector`. + /// @tparam T The data type of the struct array elements. + /// @param[in] f A function that takes the current iteration 0..vector_size-1, + /// a pointer to the struct that must be filled and the state argument. + /// @param[in] state Arbitrary state to pass to f. + /// @return Returns a typed `Offset` into the serialized data indicating + /// where the vector is stored. + /// This is mostly useful when flatbuffers are generated with mutation + /// accessors. + template<typename T, typename F, typename S> + Offset<Vector<const T *>> CreateVectorOfStructs(size_t vector_size, F f, + S *state) { + T *structs = StartVectorOfStructs<T>(vector_size); + for (size_t i = 0; i < vector_size; i++) { + f(i, structs, state); + structs++; + } + return EndVectorOfStructs<T>(vector_size); + } + + /// @brief Serialize a `std::vector` of structs into a FlatBuffer `vector`. + /// @tparam T The data type of the `std::vector` struct elements. + /// @param[in] v A const reference to the `std::vector` of structs to + /// serialize into the buffer as a `vector`. + /// @return Returns a typed `Offset` into the serialized data indicating + /// where the vector is stored. + template<typename T, typename Alloc = std::allocator<T>> + Offset<Vector<const T *>> CreateVectorOfStructs( + const std::vector<T, Alloc> &v) { + return CreateVectorOfStructs(data(v), v.size()); + } + + /// @brief Serialize a `std::vector` of native structs into a FlatBuffer + /// `vector`. + /// @tparam T The data type of the `std::vector` struct elements. + /// @tparam S The data type of the `std::vector` native struct elements. + /// @param[in] v A const reference to the `std::vector` of structs to + /// serialize into the buffer as a `vector`. + /// @param[in] pack_func Pointer to a function to convert the native struct + /// to the FlatBuffer struct. + /// @return Returns a typed `Offset` into the serialized data indicating + /// where the vector is stored. + template<typename T, typename S, typename Alloc = std::allocator<T>> + Offset<Vector<const T *>> CreateVectorOfNativeStructs( + const std::vector<S, Alloc> &v, T (*const pack_func)(const S &)) { + return CreateVectorOfNativeStructs<T, S>(data(v), v.size(), pack_func); + } + + /// @brief Serialize a `std::vector` of native structs into a FlatBuffer + /// `vector`. + /// @tparam T The data type of the `std::vector` struct elements. + /// @tparam S The data type of the `std::vector` native struct elements. + /// @param[in] v A const reference to the `std::vector` of structs to + /// serialize into the buffer as a `vector`. + /// @return Returns a typed `Offset` into the serialized data indicating + /// where the vector is stored. + template<typename T, typename S, typename Alloc = std::allocator<S>> + Offset<Vector<const T *>> CreateVectorOfNativeStructs( + const std::vector<S, Alloc> &v) { + return CreateVectorOfNativeStructs<T, S>(data(v), v.size()); + } + + /// @cond FLATBUFFERS_INTERNAL + template<typename T> struct StructKeyComparator { + bool operator()(const T &a, const T &b) const { + return a.KeyCompareLessThan(&b); + } + }; + /// @endcond + + /// @brief Serialize a `std::vector` of structs into a FlatBuffer `vector` + /// in sorted order. + /// @tparam T The data type of the `std::vector` struct elements. + /// @param[in] v A const reference to the `std::vector` of structs to + /// serialize into the buffer as a `vector`. + /// @return Returns a typed `Offset` into the serialized data indicating + /// where the vector is stored. + template<typename T, typename Alloc = std::allocator<T>> + Offset<Vector<const T *>> CreateVectorOfSortedStructs( + std::vector<T, Alloc> *v) { + return CreateVectorOfSortedStructs(data(*v), v->size()); + } + + /// @brief Serialize a `std::vector` of native structs into a FlatBuffer + /// `vector` in sorted order. + /// @tparam T The data type of the `std::vector` struct elements. + /// @tparam S The data type of the `std::vector` native struct elements. + /// @param[in] v A const reference to the `std::vector` of structs to + /// serialize into the buffer as a `vector`. + /// @return Returns a typed `Offset` into the serialized data indicating + /// where the vector is stored. + template<typename T, typename S, typename Alloc = std::allocator<T>> + Offset<Vector<const T *>> CreateVectorOfSortedNativeStructs( + std::vector<S, Alloc> *v) { + return CreateVectorOfSortedNativeStructs<T, S>(data(*v), v->size()); + } + + /// @brief Serialize an array of structs into a FlatBuffer `vector` in sorted + /// order. + /// @tparam T The data type of the struct array elements. + /// @param[in] v A pointer to the array of type `T` to serialize into the + /// buffer as a `vector`. + /// @param[in] len The number of elements to serialize. + /// @return Returns a typed `Offset` into the serialized data indicating + /// where the vector is stored. + template<typename T> + Offset<Vector<const T *>> CreateVectorOfSortedStructs(T *v, size_t len) { + std::stable_sort(v, v + len, StructKeyComparator<T>()); + return CreateVectorOfStructs(v, len); + } + + /// @brief Serialize an array of native structs into a FlatBuffer `vector` in + /// sorted order. + /// @tparam T The data type of the struct array elements. + /// @tparam S The data type of the native struct array elements. + /// @param[in] v A pointer to the array of type `S` to serialize into the + /// buffer as a `vector`. + /// @param[in] len The number of elements to serialize. + /// @return Returns a typed `Offset` into the serialized data indicating + /// where the vector is stored. + template<typename T, typename S> + Offset<Vector<const T *>> CreateVectorOfSortedNativeStructs(S *v, + size_t len) { + extern T Pack(const S &); + auto structs = StartVectorOfStructs<T>(len); + for (size_t i = 0; i < len; i++) { structs[i] = Pack(v[i]); } + std::stable_sort(structs, structs + len, StructKeyComparator<T>()); + return EndVectorOfStructs<T>(len); + } + + /// @cond FLATBUFFERS_INTERNAL + template<typename T> struct TableKeyComparator { + TableKeyComparator(vector_downward &buf) : buf_(buf) {} + TableKeyComparator(const TableKeyComparator &other) : buf_(other.buf_) {} + bool operator()(const Offset<T> &a, const Offset<T> &b) const { + auto table_a = reinterpret_cast<T *>(buf_.data_at(a.o)); + auto table_b = reinterpret_cast<T *>(buf_.data_at(b.o)); + return table_a->KeyCompareLessThan(table_b); + } + vector_downward &buf_; + + private: + FLATBUFFERS_DELETE_FUNC( + TableKeyComparator &operator=(const TableKeyComparator &other)); + }; + /// @endcond + + /// @brief Serialize an array of `table` offsets as a `vector` in the buffer + /// in sorted order. + /// @tparam T The data type that the offset refers to. + /// @param[in] v An array of type `Offset<T>` that contains the `table` + /// offsets to store in the buffer in sorted order. + /// @param[in] len The number of elements to store in the `vector`. + /// @return Returns a typed `Offset` into the serialized data indicating + /// where the vector is stored. + template<typename T> + Offset<Vector<Offset<T>>> CreateVectorOfSortedTables(Offset<T> *v, + size_t len) { + std::stable_sort(v, v + len, TableKeyComparator<T>(buf_)); + return CreateVector(v, len); + } + + /// @brief Serialize an array of `table` offsets as a `vector` in the buffer + /// in sorted order. + /// @tparam T The data type that the offset refers to. + /// @param[in] v An array of type `Offset<T>` that contains the `table` + /// offsets to store in the buffer in sorted order. + /// @return Returns a typed `Offset` into the serialized data indicating + /// where the vector is stored. + template<typename T, typename Alloc = std::allocator<T>> + Offset<Vector<Offset<T>>> CreateVectorOfSortedTables( + std::vector<Offset<T>, Alloc> *v) { + return CreateVectorOfSortedTables(data(*v), v->size()); + } + + /// @brief Specialized version of `CreateVector` for non-copying use cases. + /// Write the data any time later to the returned buffer pointer `buf`. + /// @param[in] len The number of elements to store in the `vector`. + /// @param[in] elemsize The size of each element in the `vector`. + /// @param[out] buf A pointer to a `uint8_t` pointer that can be + /// written to at a later time to serialize the data into a `vector` + /// in the buffer. + uoffset_t CreateUninitializedVector(size_t len, size_t elemsize, + uint8_t **buf) { + NotNested(); + StartVector(len, elemsize); + buf_.make_space(len * elemsize); + auto vec_start = GetSize(); + auto vec_end = EndVector(len); + *buf = buf_.data_at(vec_start); + return vec_end; + } + + /// @brief Specialized version of `CreateVector` for non-copying use cases. + /// Write the data any time later to the returned buffer pointer `buf`. + /// @tparam T The data type of the data that will be stored in the buffer + /// as a `vector`. + /// @param[in] len The number of elements to store in the `vector`. + /// @param[out] buf A pointer to a pointer of type `T` that can be + /// written to at a later time to serialize the data into a `vector` + /// in the buffer. + template<typename T> + Offset<Vector<T>> CreateUninitializedVector(size_t len, T **buf) { + AssertScalarT<T>(); + return CreateUninitializedVector(len, sizeof(T), + reinterpret_cast<uint8_t **>(buf)); + } + + template<typename T> + Offset<Vector<const T *>> CreateUninitializedVectorOfStructs(size_t len, + T **buf) { + return CreateUninitializedVector(len, sizeof(T), + reinterpret_cast<uint8_t **>(buf)); + } + + // @brief Create a vector of scalar type T given as input a vector of scalar + // type U, useful with e.g. pre "enum class" enums, or any existing scalar + // data of the wrong type. + template<typename T, typename U> + Offset<Vector<T>> CreateVectorScalarCast(const U *v, size_t len) { + AssertScalarT<T>(); + AssertScalarT<U>(); + StartVector(len, sizeof(T)); + for (auto i = len; i > 0;) { PushElement(static_cast<T>(v[--i])); } + return Offset<Vector<T>>(EndVector(len)); + } + + /// @brief Write a struct by itself, typically to be part of a union. + template<typename T> Offset<const T *> CreateStruct(const T &structobj) { + NotNested(); + Align(AlignOf<T>()); + buf_.push_small(structobj); + return Offset<const T *>(GetSize()); + } + + /// @brief Finish serializing a buffer by writing the root offset. + /// @param[in] file_identifier If a `file_identifier` is given, the buffer + /// will be prefixed with a standard FlatBuffers file header. + template<typename T> + void Finish(Offset<T> root, const char *file_identifier = nullptr) { + Finish(root.o, file_identifier, false); + } + + /// @brief Finish a buffer with a 32 bit size field pre-fixed (size of the + /// buffer following the size field). These buffers are NOT compatible + /// with standard buffers created by Finish, i.e. you can't call GetRoot + /// on them, you have to use GetSizePrefixedRoot instead. + /// All >32 bit quantities in this buffer will be aligned when the whole + /// size pre-fixed buffer is aligned. + /// These kinds of buffers are useful for creating a stream of FlatBuffers. + template<typename T> + void FinishSizePrefixed(Offset<T> root, + const char *file_identifier = nullptr) { + Finish(root.o, file_identifier, true); + } + + void SwapBufAllocator(FlatBufferBuilder &other) { + buf_.swap_allocator(other.buf_); + } + + /// @brief The length of a FlatBuffer file header. + static const size_t kFileIdentifierLength = + ::flatbuffers::kFileIdentifierLength; + + protected: + // You shouldn't really be copying instances of this class. + FlatBufferBuilder(const FlatBufferBuilder &); + FlatBufferBuilder &operator=(const FlatBufferBuilder &); + + void Finish(uoffset_t root, const char *file_identifier, bool size_prefix) { + NotNested(); + buf_.clear_scratch(); + // This will cause the whole buffer to be aligned. + PreAlign((size_prefix ? sizeof(uoffset_t) : 0) + sizeof(uoffset_t) + + (file_identifier ? kFileIdentifierLength : 0), + minalign_); + if (file_identifier) { + FLATBUFFERS_ASSERT(strlen(file_identifier) == kFileIdentifierLength); + PushBytes(reinterpret_cast<const uint8_t *>(file_identifier), + kFileIdentifierLength); + } + PushElement(ReferTo(root)); // Location of root. + if (size_prefix) { PushElement(GetSize()); } + finished = true; + } + + struct FieldLoc { + uoffset_t off; + voffset_t id; + }; + + vector_downward buf_; + + // Accumulating offsets of table members while it is being built. + // We store these in the scratch pad of buf_, after the vtable offsets. + uoffset_t num_field_loc; + // Track how much of the vtable is in use, so we can output the most compact + // possible vtable. + voffset_t max_voffset_; + + // Ensure objects are not nested. + bool nested; + + // Ensure the buffer is finished before it is being accessed. + bool finished; + + size_t minalign_; + + bool force_defaults_; // Serialize values equal to their defaults anyway. + + bool dedup_vtables_; + + struct StringOffsetCompare { + StringOffsetCompare(const vector_downward &buf) : buf_(&buf) {} + bool operator()(const Offset<String> &a, const Offset<String> &b) const { + auto stra = reinterpret_cast<const String *>(buf_->data_at(a.o)); + auto strb = reinterpret_cast<const String *>(buf_->data_at(b.o)); + return StringLessThan(stra->data(), stra->size(), strb->data(), + strb->size()); + } + const vector_downward *buf_; + }; + + // For use with CreateSharedString. Instantiated on first use only. + typedef std::set<Offset<String>, StringOffsetCompare> StringOffsetMap; + StringOffsetMap *string_pool; + + private: + // Allocates space for a vector of structures. + // Must be completed with EndVectorOfStructs(). + template<typename T> T *StartVectorOfStructs(size_t vector_size) { + StartVector(vector_size * sizeof(T) / AlignOf<T>(), AlignOf<T>()); + return reinterpret_cast<T *>(buf_.make_space(vector_size * sizeof(T))); + } + + // End the vector of structures in the flatbuffers. + // Vector should have previously be started with StartVectorOfStructs(). + template<typename T> + Offset<Vector<const T *>> EndVectorOfStructs(size_t vector_size) { + return Offset<Vector<const T *>>(EndVector(vector_size)); + } +}; +/// @} + +/// Helpers to get a typed pointer to objects that are currently being built. +/// @warning Creating new objects will lead to reallocations and invalidates +/// the pointer! +template<typename T> +T *GetMutableTemporaryPointer(FlatBufferBuilder &fbb, Offset<T> offset) { + return reinterpret_cast<T *>(fbb.GetCurrentBufferPointer() + fbb.GetSize() - + offset.o); +} + +template<typename T> +const T *GetTemporaryPointer(FlatBufferBuilder &fbb, Offset<T> offset) { + return GetMutableTemporaryPointer<T>(fbb, offset); +} + +template<typename T> +void FlatBufferBuilder::Required(Offset<T> table, voffset_t field) { + auto table_ptr = reinterpret_cast<const Table *>(buf_.data_at(table.o)); + bool ok = table_ptr->GetOptionalFieldOffset(field) != 0; + // If this fails, the caller will show what field needs to be set. + FLATBUFFERS_ASSERT(ok); + (void)ok; +} + +} // namespace flatbuffers + +#endif // FLATBUFFERS_VECTOR_DOWNWARD_H_ |