protozero: protozero::pbf_message< T > Class Template Reference

protozero 1.8.0 Minimalistic protocol buffer decoder and encoder in C++.

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Public Types | Public Member Functions | List of all members
protozero::pbf_message< T > Class Template Reference

`#include <pbf_message.hpp>`

Inheritance diagram for protozero::pbf_message< T >:
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Collaboration diagram for protozero::pbf_message< T >:
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## Public Types
using | enum_type = T
| The type of messages this class will read.
Public Types inherited from protozero::pbf_reader
using | const_bool_iterator = const_varint_iterator< int32_t>
| Forward iterator for iterating over bool (int32 varint) values.
using | const_enum_iterator = const_varint_iterator< int32_t>
| Forward iterator for iterating over enum (int32 varint) values.
using | const_int32_iterator = const_varint_iterator< int32_t>
| Forward iterator for iterating over int32 (varint) values.
using | const_sint32_iterator = const_svarint_iterator<int32_t>
| Forward iterator for iterating over sint32 (varint) values.
using | const_uint32_iterator = const_varint_iterator<uint32_t>
| Forward iterator for iterating over uint32 (varint) values.
using | const_int64_iterator = const_varint_iterator< int64_t>
| Forward iterator for iterating over int64 (varint) values.
using | const_sint64_iterator = const_svarint_iterator<int64_t>
| Forward iterator for iterating over sint64 (varint) values.
using | const_uint64_iterator = const_varint_iterator<uint64_t>
| Forward iterator for iterating over uint64 (varint) values.
using | const_fixed32_iterator = const_fixed_iterator<uint32_t>
| Forward iterator for iterating over fixed32 values.
using | const_sfixed32_iterator = const_fixed_iterator<int32_t>
| Forward iterator for iterating over sfixed32 values.
using | const_fixed64_iterator = const_fixed_iterator<uint64_t>
| Forward iterator for iterating over fixed64 values.
using | const_sfixed64_iterator = const_fixed_iterator<int64_t>
| Forward iterator for iterating over sfixed64 values.
using | const_float_iterator = const_fixed_iterator<float>
| Forward iterator for iterating over float values.
using | const_double_iterator = const_fixed_iterator<double>
| Forward iterator for iterating over double values.

## Public Member Functions
template<typename... Args>
| pbf_message (Args &&... args) noexcept
bool | next ()
bool | next (T next_tag)
bool | next (T next_tag, pbf_wire_type type)
T | tag () const noexcept
Public Member Functions inherited from protozero::pbf_reader
| pbf_reader (const data_view &view) noexcept
| pbf_reader (const char *data, std::size_t size) noexcept
| pbf_reader (const std::pair< const char *, std::size_t > &data) noexcept
| pbf_reader (const std::string &data) noexcept
| pbf_reader () noexcept=default
| pbf_reader (const pbf_reader &) noexcept=default
| pbf_reader messages can be copied trivially.
| pbf_reader (pbf_reader &&) noexcept=default
| pbf_reader messages can be moved trivially.
pbf_reader & | operator= (const pbf_reader &other) noexcept=default
| pbf_reader messages can be copied trivially.
pbf_reader & | operator= (pbf_reader &&other) noexcept=default
| pbf_reader messages can be moved trivially.
void | swap (pbf_reader &other) noexcept
| operator bool () const noexcept
data_view | data () const noexcept
std::size_t | length () const noexcept
bool | next ()
bool | next (pbf_tag_type next_tag)
bool | next (pbf_tag_type next_tag, pbf_wire_type type)
pbf_tag_type | tag () const noexcept
pbf_wire_type | wire_type () const noexcept
uint32_t | tag_and_type () const noexcept
bool | has_wire_type (pbf_wire_type type) const noexcept
void | skip ()
bool | get_bool ()
int32_t | get_enum ()
int32_t | get_int32 ()
int32_t | get_sint32 ()
uint32_t | get_uint32 ()
int64_t | get_int64 ()
int64_t | get_sint64 ()
uint64_t | get_uint64 ()
uint32_t | get_fixed32 ()
int32_t | get_sfixed32 ()
uint64_t | get_fixed64 ()
int64_t | get_sfixed64 ()
float | get_float ()
double | get_double ()
data_view | get_view ()
std::pair< const char *, pbf_length_type > | get_data ()
std::string | get_bytes ()
std::string | get_string ()
pbf_reader | get_message ()
iterator_range< pbf_reader::const_bool_iterator > | get_packed_bool ()
iterator_range< pbf_reader::const_enum_iterator > | get_packed_enum ()
iterator_range< pbf_reader::const_int32_iterator > | get_packed_int32 ()
iterator_range< pbf_reader::const_sint32_iterator > | get_packed_sint32 ()
iterator_range< pbf_reader::const_uint32_iterator > | get_packed_uint32 ()
iterator_range< pbf_reader::const_int64_iterator > | get_packed_int64 ()
iterator_range< pbf_reader::const_sint64_iterator > | get_packed_sint64 ()
iterator_range< pbf_reader::const_uint64_iterator > | get_packed_uint64 ()
iterator_range< pbf_reader::const_fixed32_iterator > | get_packed_fixed32 ()
iterator_range< pbf_reader::const_sfixed32_iterator > | get_packed_sfixed32 ()
iterator_range< pbf_reader::const_fixed64_iterator > | get_packed_fixed64 ()
iterator_range< pbf_reader::const_sfixed64_iterator > | get_packed_sfixed64 ()
iterator_range< pbf_reader::const_float_iterator > | get_packed_float ()
iterator_range< pbf_reader::const_double_iterator > | get_packed_double ()

## Detailed Description

template<typename T>
class protozero::pbf_message< T >

This class represents a protobuf message. Either a top-level message or a nested sub-message. Top-level messages can be created from any buffer with a pointer and length:

enum class Message : protozero::pbf_tag_type {
...
};
std::string buffer;
// fill buffer...
pbf_message<Message> message{buffer.data(), buffer.size()};
protozero::pbf_message
Definition pbf_message.hpp:65
protozero::pbf_tag_type
uint32_t pbf_tag_type
Definition types.hpp:33

Sub-messages are created using get_message():

enum class SubMessage : protozero::pbf_tag_type {
...
};
pbf_message<Message> message{...};
message.next();
pbf_message<SubMessage> submessage = message.get_message();
protozero::pbf_message::next
bool next()
Definition pbf_message.hpp:99
protozero::pbf_message::pbf_message
pbf_message(Args &&... args) noexcept
Definition pbf_message.hpp:80

All methods of the pbf_message class except get_bytes() and get_string() provide the strong exception guarantee, ie they either succeed or do not change the pbf_message object they are called on. Use the get_data() method instead of get_bytes() or get_string(), if you need this guarantee.

This template class is based on the pbf_reader class and has all the same methods. The difference is that whereever the pbf_reader class takes an integer tag, this template class takes a tag of the template type T.

Read the tutorial to understand how this class is used.

## Constructor & Destructor Documentation

## ◆ pbf_message()

template<typename T>
template<typename... Args>

protozero::pbf_message< T >::pbf_message | ( | Args &&... | args | ) |
| inlinenoexcept

Construct a pbf_message. All arguments are forwarded to the pbf_reader parent class.

## Member Function Documentation

## ◆ next() [1/3]

template<typename T>

bool protozero::pbf_message< T >::next | ( |  | ) |
| inline

Set next field in the message as the current field. This is usually called in a while loop:

pbf_message<...> message(...);
while (message.next()) {
// handle field
}

Returns
  `true` if there is a next field, `false` if not.

Precondition
  There must be no current field.

Postcondition
  If it returns `true` there is a current field now.

## ◆ next() [2/3]

template<typename T>

bool protozero::pbf_message< T >::next | ( | T | next_tag | ) |
| inline

Set next field with given tag in the message as the current field. Fields with other tags are skipped. This is usually called in a while loop for repeated fields:

pbf_message<Example1> message{...};
while (message.next(Example1::repeated_fixed64_r)) {
// handle field
}

or you can call it just once to get the one field with this tag:

pbf_message<Example1> message{...};
if (message.next(Example1::required_uint32_x)) {
// handle field
}

Note that this will not check the wire type. The two-argument version of this function will also check the wire type.

Returns
  `true` if there is a next field with this tag.

Precondition
  There must be no current field.

Postcondition
  If it returns `true` there is a current field now with the given tag.

## ◆ next() [3/3]

template<typename T>

bool protozero::pbf_message< T >::next | ( | T | next_tag,
|  | pbf_wire_type | type )
| inline

Set next field with given tag and wire type in the message as the current field. Fields with other tags are skipped. This is usually called in a while loop for repeated fields:

pbf_message<Example1> message{...};
while (message.next(Example1::repeated_fixed64_r, pbf_wire_type::varint)) {
// handle field
}

or you can call it just once to get the one field with this tag:

pbf_message<Example1> message{...};
if (message.next(Example1::required_uint32_x, pbf_wire_type::varint)) {
// handle field
}

Note that this will also check the wire type. The one-argument version of this function will not check the wire type.

Returns
  `true` if there is a next field with this tag.

Precondition
  There must be no current field.

Postcondition
  If it returns `true` there is a current field now with the given tag.

## ◆ tag()

template<typename T>

T protozero::pbf_message< T >::tag | ( |  | ) | const
| inlinenoexcept

The tag of the current field. The tag is the enum value for the field number from the description in the .proto file.

Call next() before calling this function to set the current field.

Returns
  tag of the current field.

Precondition
  There must be a current field (ie. next() must have returned `true`).

The documentation for this class was generated from the following file:

- include/protozero/pbf_message.hpp