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// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// This file contains declarations needed in generated headers for messages
// that use tail-call table parsing. Everything in this file is for internal
// use only.
#ifndef GOOGLE_PROTOBUF_GENERATED_MESSAGE_TCTABLE_DECL_H__
#define GOOGLE_PROTOBUF_GENERATED_MESSAGE_TCTABLE_DECL_H__
#include <array>
#include <cstddef>
#include <cstdint>
#include <type_traits>
#include <google/protobuf/message_lite.h>
#include <google/protobuf/parse_context.h>
// Must come last:
#include <google/protobuf/port_def.inc>
namespace google {
namespace protobuf {
namespace internal {
// Additional information about this field:
struct TcFieldData {
constexpr TcFieldData() : data(0) {}
// Fast table entry constructor:
constexpr TcFieldData(uint16_t coded_tag, uint8_t hasbit_idx, uint8_t aux_idx,
uint16_t offset)
: data(uint64_t{offset} << 48 | //
uint64_t{aux_idx} << 24 | //
uint64_t{hasbit_idx} << 16 | //
uint64_t{coded_tag}) {}
// Fields used in fast table parsing:
//
// Bit:
// +-----------+-------------------+
// |63 .. 32|31 .. 0|
// +---------------+---------------+
// : . : . : . 16|=======| [16] coded_tag()
// : . : . : 24|===| . : [ 8] hasbit_idx()
// : . : . 32|===| : . : [ 8] aux_idx()
// : . 48:---.---: . : . : [16] (unused)
// |=======| . : . : . : [16] offset()
// +-----------+-------------------+
// |63 .. 32|31 .. 0|
// +---------------+---------------+
template <typename TagType = uint16_t>
TagType coded_tag() const {
return static_cast<TagType>(data);
}
uint8_t hasbit_idx() const { return static_cast<uint8_t>(data >> 16); }
uint8_t aux_idx() const { return static_cast<uint8_t>(data >> 24); }
uint16_t offset() const { return static_cast<uint16_t>(data >> 48); }
// Fields used in mini table parsing:
//
// Bit:
// +-----------+-------------------+
// |63 .. 32|31 .. 0|
// +---------------+---------------+
// : . : . |===============| [32] tag() (decoded)
// |===============| . : . : [32] entry_offset()
// +-----------+-------------------+
// |63 .. 32|31 .. 0|
// +---------------+---------------+
uint32_t tag() const { return static_cast<uint32_t>(data); }
uint32_t entry_offset() const { return static_cast<uint32_t>(data >> 32); }
uint64_t data;
};
struct TcParseTableBase;
// TailCallParseFunc is the function pointer type used in the tailcall table.
typedef const char* (*TailCallParseFunc)(PROTOBUF_TC_PARAM_DECL);
namespace field_layout {
struct Offset {
uint32_t off;
};
} // namespace field_layout
#if defined(_MSC_VER) && !defined(_WIN64)
#pragma warning(push)
// TcParseTableBase is intentionally overaligned on 32 bit targets.
#pragma warning(disable : 4324)
#endif
// Base class for message-level table with info for the tail-call parser.
struct alignas(uint64_t) TcParseTableBase {
// Common attributes for message layout:
uint16_t has_bits_offset;
uint16_t extension_offset;
uint32_t extension_range_low;
uint32_t extension_range_high;
uint32_t max_field_number;
uint8_t fast_idx_mask;
uint16_t lookup_table_offset;
uint32_t skipmap32;
uint32_t field_entries_offset;
uint16_t num_field_entries;
uint16_t num_aux_entries;
uint32_t aux_offset;
const MessageLite* default_instance;
// Handler for fields which are not handled by table dispatch.
TailCallParseFunc fallback;
// This constructor exactly follows the field layout, so it's technically
// not necessary. However, it makes it much much easier to add or re-arrange
// fields, because it can be overloaded with an additional constructor,
// temporarily allowing both old and new protocol buffer headers to be
// compiled.
constexpr TcParseTableBase(
uint16_t has_bits_offset, uint16_t extension_offset,
uint32_t extension_range_low, uint32_t extension_range_high,
uint32_t max_field_number, uint8_t fast_idx_mask,
uint16_t lookup_table_offset, uint32_t skipmap32,
uint32_t field_entries_offset, uint16_t num_field_entries,
uint16_t num_aux_entries, uint32_t aux_offset,
const MessageLite* default_instance, TailCallParseFunc fallback)
: has_bits_offset(has_bits_offset),
extension_offset(extension_offset),
extension_range_low(extension_range_low),
extension_range_high(extension_range_high),
max_field_number(max_field_number),
fast_idx_mask(fast_idx_mask),
lookup_table_offset(lookup_table_offset),
skipmap32(skipmap32),
field_entries_offset(field_entries_offset),
num_field_entries(num_field_entries),
num_aux_entries(num_aux_entries),
aux_offset(aux_offset),
default_instance(default_instance),
fallback(fallback) {}
// Table entry for fast-path tailcall dispatch handling.
struct FastFieldEntry {
// Target function for dispatch:
TailCallParseFunc target;
// Field data used during parse:
TcFieldData bits;
};
// There is always at least one table entry.
const FastFieldEntry* fast_entry(size_t idx) const {
return reinterpret_cast<const FastFieldEntry*>(this + 1) + idx;
}
// Returns a begin iterator (pointer) to the start of the field lookup table.
const uint16_t* field_lookup_begin() const {
return reinterpret_cast<const uint16_t*>(reinterpret_cast<uintptr_t>(this) +
lookup_table_offset);
}
// Field entry for all fields.
struct FieldEntry {
uint32_t offset; // offset in the message object
int32_t has_idx; // has-bit index
uint16_t aux_idx; // index for `field_aux`.
uint16_t type_card; // `FieldType` and `Cardinality` (see _impl.h)
};
// Returns a begin iterator (pointer) to the start of the field entries array.
const FieldEntry* field_entries_begin() const {
return reinterpret_cast<const FieldEntry*>(
reinterpret_cast<uintptr_t>(this) + field_entries_offset);
}
// Auxiliary entries for field types that need extra information.
union FieldAux {
constexpr FieldAux() : message_default(nullptr) {}
constexpr FieldAux(bool (*enum_validator)(int))
: enum_validator(enum_validator) {}
constexpr FieldAux(field_layout::Offset off) : offset(off.off) {}
constexpr FieldAux(int16_t range_start, uint16_t range_length)
: enum_range{range_start, range_length} {}
constexpr FieldAux(const MessageLite* msg) : message_default(msg) {}
bool (*enum_validator)(int);
struct {
int16_t start; // minimum enum number (if it fits)
uint16_t length; // length of range (i.e., max = start + length - 1)
} enum_range;
uint32_t offset;
const MessageLite* message_default;
};
const FieldAux* field_aux(uint32_t idx) const {
return reinterpret_cast<const FieldAux*>(reinterpret_cast<uintptr_t>(this) +
aux_offset) +
idx;
}
const FieldAux* field_aux(const FieldEntry* entry) const {
return field_aux(entry->aux_idx);
}
// Field name data
const char* name_data() const {
return reinterpret_cast<const char*>(reinterpret_cast<uintptr_t>(this) +
aux_offset +
num_aux_entries * sizeof(FieldAux));
}
};
#if defined(_MSC_VER) && !defined(_WIN64)
#pragma warning(pop)
#endif
static_assert(sizeof(TcParseTableBase::FastFieldEntry) <= 16,
"Fast field entry is too big.");
static_assert(sizeof(TcParseTableBase::FieldEntry) <= 16,
"Field entry is too big.");
template <size_t kFastTableSizeLog2, size_t kNumFieldEntries = 0,
size_t kNumFieldAux = 0, size_t kNameTableSize = 0,
size_t kFieldLookupSize = 2>
struct TcParseTable {
TcParseTableBase header;
// Entries for each field.
//
// Fields are indexed by the lowest bits of their field number. The field
// number is masked to fit inside the table. Note that the parsing logic
// generally calls `TailCallParseTableBase::fast_entry()` instead of accessing
// this field directly.
std::array<TcParseTableBase::FastFieldEntry, (1 << kFastTableSizeLog2)>
fast_entries;
// Just big enough to find all the field entries.
std::array<uint16_t, kFieldLookupSize> field_lookup_table;
// Entries for all fields:
std::array<TcParseTableBase::FieldEntry, kNumFieldEntries> field_entries;
std::array<TcParseTableBase::FieldAux, kNumFieldAux> aux_entries;
std::array<char, kNameTableSize> field_names;
};
// Partial specialization: if there are no aux entries, there will be no array.
// In C++, arrays cannot have length 0, but (C++11) std::array<T, 0> is valid.
// However, different implementations have different sizeof(std::array<T, 0>).
// Skipping the member makes offset computations portable.
template <size_t kFastTableSizeLog2, size_t kNumFieldEntries,
size_t kNameTableSize, size_t kFieldLookupSize>
struct TcParseTable<kFastTableSizeLog2, kNumFieldEntries, 0, kNameTableSize,
kFieldLookupSize> {
TcParseTableBase header;
std::array<TcParseTableBase::FastFieldEntry, (1 << kFastTableSizeLog2)>
fast_entries;
std::array<uint16_t, kFieldLookupSize> field_lookup_table;
std::array<TcParseTableBase::FieldEntry, kNumFieldEntries> field_entries;
std::array<char, kNameTableSize> field_names;
};
// Partial specialization: if there are no fields at all, then we can save space
// by skipping the field numbers and entries.
template <size_t kNameTableSize, size_t kFieldLookupSize>
struct TcParseTable<0, 0, 0, kNameTableSize, kFieldLookupSize> {
TcParseTableBase header;
// N.B.: the fast entries are sized by log2, so 2**0 fields = 1 entry.
// The fast parsing loop will always use this entry, so it must be present.
std::array<TcParseTableBase::FastFieldEntry, 1> fast_entries;
std::array<uint16_t, kFieldLookupSize> field_lookup_table;
std::array<char, kNameTableSize> field_names;
};
static_assert(std::is_standard_layout<TcParseTable<1>>::value,
"TcParseTable must be standard layout.");
static_assert(offsetof(TcParseTable<1>, fast_entries) ==
sizeof(TcParseTableBase),
"Table entries must be laid out after TcParseTableBase.");
} // namespace internal
} // namespace protobuf
} // namespace google
#include <google/protobuf/port_undef.inc>
#endif // GOOGLE_PROTOBUF_GENERATED_MESSAGE_TCTABLE_DECL_H__