centipede::writer::Binary Class Reference

Class for writing binary files. More...

#include <binary.hpp>

Classes
class	Config
	Class for configuring the binary writer class (Binary). More...

Public Types
using	BufferType = std::pair<std::vector<uint32_t>, std::vector<float>>
	Type of the data_buffer_.
using	BufferPoint = std::pair<uint32_t, float>
	Type of the buffer point stored in the data_buffer_.

Public Member Functions
	Binary ()=default
	Default constructor.
constexpr	Binary (Config config)
	Constructor takes an argument for the configuration.
auto	init () -> EnumError<>
	Initialization.
template<std::size_t NLocals, std::size_t NGlobals>
auto	add_entrypoint (const EntryPoint< NLocals, NGlobals > &entry_point) -> EnumError<>
	Add an entrypoint to the internal data buffer.
auto	write_current_entry () -> EnumError< std::size_t >
	Streaming an entry data to the output file.
void	close ()
	Manually close the output file handler.
constexpr auto	get_config () const -> const Config &
	Getter of the configuration.
constexpr auto	get_buffer () const -> const BufferType &
	Getter of the buffer.

Private Attributes
Config	config_
	Member variable for the configuration.
BufferType	data_buffer_
	Data buffer to store entry_point.
std::ofstream	output_file_
	Output file handler.

Detailed Description

Data is written to the binary file via each entry, which contains different entrypoints (of the type centipede::EntryPoint). Before any operation, the Binary::init() function must be called, where the file handler is opened and internal buffer resetted, ready for the next data input. When adding each entrypoint, the writer doesn't write the corresponding data to the binary file, but rather pushes the data to its internal buffer (see Binary::data_buffer_). Data is only written to the binary file after calling Binary::write_current_entry(). All entrypoints added before this call are grouped into the same entry.

Configuration of the class is done via the Binary::Config struct.

Example usage

#include <centipede/centipede.hpp>
#include <print>
 
auto writer = centipede::writer::Binary{};
 
auto init_err = writer.init()
 
if(not init_err.has_value())
{
     // Prints the error message here.
     std::println(stderr, "Error: {}", init_err.error());
}
 
// Starts to write entrypoint
auto entry_point = get_new_entry_point();
auto add_err = writer.add_entrypoint(entry_point);
 
// Deal with add_err here.
if(not add_err.has_value()) { ... }
 
// Write current entry to the file.
auto write_err = writer.write_current_entry();
 
// Deal with write_err here.
if(not write_err.has_value()) { ... }

For a complete example, please check out test_writer.cpp.

Definition at line 62 of file binary.hpp.

Constructor & Destructor Documentation

Binary()

centipede::writer::Binary::Binary ( Config config )

inlineexplicitconstexpr

The config argument will be moved (std::move) to its member variable config_

Parameters

config

Configuration struct.

See also

Config

Definition at line 100 of file binary.hpp.

Member Function Documentation

add_entrypoint()

template<std::size_t NLocals, std::size_t NGlobals>

auto centipede::writer::Binary::add_entrypoint ( const EntryPoint< NLocals, NGlobals > & entry_point ) -> EnumError<>

nodiscard

The adding of an entrypoint to the data buffer follows the sequence:

1. If the sigma value is negative, returns immediately.
2. Check if the current internal buffer has enough of space to store the latest data point.
3. Add an index-value pair [0, measurement] as one buffer point to the data buffer.
4. Add all local derivatives with indices as buffer points to the data buffer.
5. Add an index-value pair [0, sigma] as one buffer point to the data buffer.
6. Add all global derivatives with indices as buffer points to the data buffer.

Parameters

entry_point

Input data structure which stores the local/global derivatives, measurement and error.

Returns

• ErrorCode::writer_neg_or_zero_sigma if the sigma value is zero or negative.
• ErrorCode::writer_buffer_overflow if the buffer size is too small for the new entrypoint.
• ErrorCode::writer_entrypoint_rejected if the derivative values from the entrypoint are all zero.

Definition at line 183 of file binary.hpp.

close()

void centipede::writer::Binary::close ( )

inline

This function will be called automatically when the destructor is called.

Definition at line 151 of file binary.hpp.

get_buffer()

auto centipede::writer::Binary::get_buffer ( ) const -> const BufferType &

inlineconstexpr

Returns

Returns a const reference to the member variable data_buffer_.

See also

ref

Definition at line 167 of file binary.hpp.

get_config()

auto centipede::writer::Binary::get_config ( ) const -> const Config &

inlineconstexpr

Returns

Returns a const reference to the member variable config_.

See also

ref

Definition at line 159 of file binary.hpp.

init()

auto centipede::writer::Binary::init ( ) -> EnumError<>

nodiscard

The initialization function must be called before calling the add_entrypoint() method. When calling this function, data_buffer_ is resetted and a file is opened with the specified name in Config.

Returns

Returns ErrorCode::writer_file_fail_to_open if the file cannot be opened with the name specified by Config::out_filename.

See also

Config

Definition at line 50 of file binary.cpp.

write_current_entry()

auto centipede::writer::Binary::write_current_entry

(

)

-> EnumError< std::size_t >

Streaming the entry data to the output file and call the reset() function to clear the internal buffer. After the function is called, the writer is waiting for a new entry to be added.

Returns

Number of bytes written to the binary file.

Definition at line 63 of file binary.cpp.

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

• source/centipede/writer/binary.hpp
• source/centipede/writer/binary.cpp