osmium::io::Reader Class Reference

#include <reader.hpp>

Inheritance diagram for osmium::io::Reader:

Collaboration diagram for osmium::io::Reader:

Public Member Functions
template<typename... TArgs>
	Reader (const osmium::io::File &file, TArgs &&... args)
template<typename... TArgs>
	Reader (const std::string &filename, TArgs &&... args)
template<typename... TArgs>
	Reader (const char *filename, TArgs &&... args)
	Reader (const Reader &)=delete
Reader &	operator= (const Reader &)=delete
	Reader (Reader &&)=delete
Reader &	operator= (Reader &&)=delete
	~Reader () noexcept
void	close ()
osmium::io::Header	header ()
osmium::memory::Buffer	read ()
bool	eof () const
std::size_t	file_size () const noexcept
std::size_t	offset () const noexcept

Private Types
enum class	status { okay = 0 , error = 1 , closed = 2 , eof = 3 }

Private Member Functions
void	set_option (osmium::thread::Pool &pool) noexcept
void	set_option (osmium::osm_entity_bits::type value) noexcept
void	set_option (osmium::io::read_meta value) noexcept
void	set_option (osmium::io::buffers_type value) noexcept

Static Private Member Functions
static void	parser_thread (osmium::thread::Pool &pool, int fd, const detail::ParserFactory::create_parser_type &creator, detail::future_string_queue_type &input_queue, detail::future_buffer_queue_type &osmdata_queue, std::promise< osmium::io::Header > &&header_promise, std::atomic< std::size_t > *offset_ptr, osmium::osm_entity_bits::type read_which_entities, osmium::io::read_meta read_metadata, osmium::io::buffers_type buffers_kind, bool want_buffered_pages_removed)
static int	execute (const std::string &command, const std::string &filename, int *childpid)
static int	open_input_file_or_url (const std::string &filename, int *childpid)
static std::unique_ptr< Decompressor >	make_decompressor (const osmium::io::File &file, int fd, std::atomic< std::size_t > *offset_ptr)

Private Attributes
osmium::memory::Buffer	m_back_buffers {}
osmium::io::File	m_file
osmium::thread::Pool *	m_pool = nullptr
std::atomic< std::size_t >	m_offset {0}
detail::ParserFactory::create_parser_type	m_creator
enum osmium::io::Reader::status	m_status = status::okay
int	m_childpid = 0
detail::future_string_queue_type	m_input_queue
int	m_fd = -1
std::size_t	m_file_size = 0
std::unique_ptr< osmium::io::Decompressor >	m_decompressor
osmium::io::detail::ReadThreadManager	m_read_thread_manager
detail::future_buffer_queue_type	m_osmdata_queue
detail::queue_wrapper< osmium::memory::Buffer >	m_osmdata_queue_wrapper
std::future< osmium::io::Header >	m_header_future {}
osmium::io::Header	m_header {}
osmium::thread::thread_handler	m_thread {}
osmium::osm_entity_bits::type	m_read_which_entities = osmium::osm_entity_bits::all
osmium::io::read_meta	m_read_metadata = osmium::io::read_meta::yes
osmium::io::buffers_type	m_buffers_kind = osmium::io::buffers_type::any

Detailed Description

This is the user-facing interface for reading OSM files. Instantiate an object of this class with a file name or osmium::io::File object and then call read() on it in a loop until it returns an invalid Buffer.

Member Enumeration Documentation

status

enum class osmium::io::Reader::status

strongprivate

Enumerator
okay
error
closed
eof

Constructor & Destructor Documentation

Reader() [1/5]

template<typename... TArgs>

osmium::io::Reader::Reader ( const osmium::io::File &  file, TArgs &&...  args  )

inlineexplicit

Create new Reader object.

Parameters

file	The file (contains name and format info) to open.
args	All further arguments are optional and can appear in any order:

• osmium::osm_entities::bits: Which OSM entities (nodes, ways, relations, and/or changesets) should be read from the input file. It can speed the read up significantly if objects that are not needed anyway are not parsed.
• osmium::io::read_meta: Read meta data or not. The default is osmium::io::read_meta::yes which means that meta data is read normally. If you set this to osmium::io::read_meta::no, meta data (like version, uid, etc.) is not read possibly speeding up the read. Not all file formats use this setting. Do not set this to osmium::io::read_meta::no for history or change files because you will loose the information whether an object is visible!
• osmium::io::buffers_type: Fill entities into buffers until the buffers are full (osmium::io::buffers_type::any) or only fill entities of the same type into a buffer (osmium::io::buffers_type::single). Every time a new entity type is seen a new buffer will be started. Do not use in "single" mode if the input file is not sorted by type, otherwise this will be rather inefficient.
• osmium::thread::Pool&: Reference to a thread pool that should be used for reading instead of the default pool. Usually it is okay to use the statically initialized shared default pool, but sometimes you want or need your own. For instance when your program will fork, using the statically initialized pool will not work.

Exceptions

osmium::io_error	If there was an error.
std::system_error	If the file could not be opened.

Reader() [2/5]

template<typename... TArgs>

osmium::io::Reader::Reader ( const std::string &  filename, TArgs &&...  args  )

inlineexplicit

Reader() [3/5]

template<typename... TArgs>

osmium::io::Reader::Reader ( const char *  filename, TArgs &&...  args  )

inlineexplicit

Reader() [4/5]

osmium::io::Reader::Reader ( const Reader &  )

delete

Reader() [5/5]

osmium::io::Reader::Reader ( Reader &&  )

delete

~Reader()

osmium::io::Reader::~Reader ( )

inlinenoexcept

Member Function Documentation

close()

void osmium::io::Reader::close ( )

inline

Close down the Reader. A call to this is optional, because the destructor of Reader will also call this. But if you don't call this function first, you might miss an exception, because the destructor is not allowed to throw.

Exceptions

Some	form of osmium::io_error when there is a problem.

eof()

bool osmium::io::Reader::eof ( ) const

inline

Has the end of file been reached? This is set after the last data has been read. It is also set by calling close().

execute()

static int osmium::io::Reader::execute ( const std::string &  command, const std::string &  filename, int *  childpid  )

inlinestaticprivate

Fork and execute the given command in the child. A pipe is created between the child and the parent. The child writes to the pipe, the parent reads from it. This function never returns in the child.

Parameters

command	Command to execute in the child.
filename	Filename to give to command as argument.

Returns

File descriptor of pipe in the parent.

Exceptions

std::system_error

if a system call fails.

file_size()

std::size_t osmium::io::Reader::file_size ( ) const

inlinenoexcept

Get the size of the input file. Returns 0 if the file size is not available (for instance when reading from stdin).

header()

osmium::io::Header osmium::io::Reader::header ( )

inline

Get the header data from the file.

Returns

Header.

Exceptions

Some	form of osmium::io_error if there is an error.

make_decompressor()

static std::unique_ptr< Decompressor > osmium::io::Reader::make_decompressor ( const osmium::io::File &  file, int  fd, std::atomic< std::size_t > *  offset_ptr  )

inlinestaticprivate

offset()

std::size_t osmium::io::Reader::offset ( ) const

inlinenoexcept

Returns the current offset into the input file. Returns 0 if the offset is not available (for instance when reading from stdin).

The offset can be used together with the result of file_size() to estimate how much of the file has been read. Note that due to buffering inside Osmium, this value will be larger than the amount of data actually available to the application.

Do not call this function too often, certainly not for every object you are reading. Depending on the file type it might do an expensive system call.

open_input_file_or_url()

static int osmium::io::Reader::open_input_file_or_url ( const std::string &  filename, int *  childpid  )

inlinestaticprivate

Open File for reading. Handles URLs or normal files. URLs are opened by executing the "curl" program (which must be installed) and reading from its output.

Returns

File descriptor of open file or pipe.

Exceptions

std::system_error

if a system call fails.

operator=() [1/2]

Reader & osmium::io::Reader::operator= ( const Reader &  )

delete

operator=() [2/2]

Reader & osmium::io::Reader::operator= ( Reader &&  )

delete

parser_thread()

static void osmium::io::Reader::parser_thread ( osmium::thread::Pool &  pool, int  fd, const detail::ParserFactory::create_parser_type &  creator, detail::future_string_queue_type &  input_queue, detail::future_buffer_queue_type &  osmdata_queue, std::promise< osmium::io::Header > &&  header_promise, std::atomic< std::size_t > *  offset_ptr, osmium::osm_entity_bits::type  read_which_entities, osmium::io::read_meta  read_metadata, osmium::io::buffers_type  buffers_kind, bool  want_buffered_pages_removed  )

inlinestaticprivate

read()

osmium::memory::Buffer osmium::io::Reader::read ( )

inline

Reads the next buffer from the input. An invalid buffer signals end-of-file. After end-of-file all read() calls will throw an osmium::io_error.

Returns

Buffer.

Exceptions

Some	form of osmium::io_error if there is an error.

set_option() [1/4]

void osmium::io::Reader::set_option ( osmium::io::buffers_type  value )

inlineprivatenoexcept

set_option() [2/4]

void osmium::io::Reader::set_option ( osmium::io::read_meta  value )

inlineprivatenoexcept

set_option() [3/4]

void osmium::io::Reader::set_option ( osmium::osm_entity_bits::type  value )

inlineprivatenoexcept

set_option() [4/4]

void osmium::io::Reader::set_option ( osmium::thread::Pool &  pool )

inlineprivatenoexcept

Member Data Documentation

m_back_buffers

osmium::memory::Buffer osmium::io::Reader::m_back_buffers {}

private

m_buffers_kind

osmium::io::buffers_type osmium::io::Reader::m_buffers_kind = osmium::io::buffers_type::any

private

m_childpid

int osmium::io::Reader::m_childpid = 0

private

m_creator

detail::ParserFactory::create_parser_type osmium::io::Reader::m_creator

private

m_decompressor

std::unique_ptr<osmium::io::Decompressor> osmium::io::Reader::m_decompressor

private

m_fd

int osmium::io::Reader::m_fd = -1

private

m_file

osmium::io::File osmium::io::Reader::m_file

private

m_file_size

std::size_t osmium::io::Reader::m_file_size = 0

private

m_header

osmium::io::Header osmium::io::Reader::m_header {}

private

m_header_future

std::future<osmium::io::Header> osmium::io::Reader::m_header_future {}

private

m_input_queue

detail::future_string_queue_type osmium::io::Reader::m_input_queue

private

m_offset

std::atomic<std::size_t> osmium::io::Reader::m_offset {0}

private

m_osmdata_queue

detail::future_buffer_queue_type osmium::io::Reader::m_osmdata_queue

private

m_osmdata_queue_wrapper

detail::queue_wrapper<osmium::memory::Buffer> osmium::io::Reader::m_osmdata_queue_wrapper

private

m_pool

osmium::thread::Pool* osmium::io::Reader::m_pool = nullptr

private

m_read_metadata

osmium::io::read_meta osmium::io::Reader::m_read_metadata = osmium::io::read_meta::yes

private

m_read_thread_manager

osmium::io::detail::ReadThreadManager osmium::io::Reader::m_read_thread_manager

private

m_read_which_entities

osmium::osm_entity_bits::type osmium::io::Reader::m_read_which_entities = osmium::osm_entity_bits::all

private

m_status

enum osmium::io::Reader::status osmium::io::Reader::m_status = status::okay

private

m_thread

osmium::thread::thread_handler osmium::io::Reader::m_thread {}

private

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

• include/osmium/io/reader.hpp