Namespace hdf5::file

Enumerations

The File class

class hdf5::file::File

Public Functions

File() = default

default constructor

Use default implementation here. We need this to store instances of this class in an STL container. A default constructed instance of File is in an invalid state. This can be checked using the is_valid() method.

See also

is_valid()

File(const File&) = default

copy constructor

Use default implementation here.

File(File&&) = default

move constructor

Use default implementation here.

explicit File(ObjectHandle &&handle)

constructor

Construct a file from an rvalue reference to a handle.

Parameters

handle – rvalue reference to the file handler

AccessFlags intent() const

get access flags for the file

Throws

std::runtime_error – in case of a failure

size_t size() const

get the file size in bytes

Throws

std::runtime_error – in case of a failure

ssize_t buffer_size() const

get the buffer size in bytes

Throws

std::runtime_error – in case of a failure

void flush(Scope scope) const

flush the file

Throws

std::runtime_error – in case of a failure

Parameters

scope – the scope within which the file should be flushed

void close()

close the file

Throws

std::runtime_error – in case of a failure

fs::path path() const

get path on file system

Return the file system path of the file.

size_t count_open_objects(SearchFlags flag) const

count number of open objects

Return the number of open objects belonging to that very file instance.

node::Group root(const property::GroupAccessList &gapl = property::GroupAccessList()) const

get root group

Return an instance to the root group of the file.

Throws

std::runtime_error – in case of a failure

Parameters

gapl – reference to a group access property list

Returns

new instance of node::Group

template<typename T>
size_t to_buffer(T &data) const

retrieve a copy of the image of an existing, open file

See also

ImageFlags

Throws

std::runtime_error – in case of a failure

Template Parameters

T – source type

Parameters

data – reference to the source instance of T

Returns

size of used space in a buffer

bool is_valid() const

check validity of the instance

Return true if the instance refers to a valid HDF5 file instance.

Throws

std::runtime_error – in case of a failure

Returns

true if valid, false otherwise

ObjectId id() const

return a unique id for the file object

Return an instance of ObjectId which uniquely identifies a file object.

Functions

File hdf5::file::create(const fs::path &path, AccessFlags flags = AccessFlags::EXCLUSIVE, const property::FileCreationList &fcpl = property::FileCreationList(), const property::FileAccessList &fapl = property::FileAccessList())

create a new file

See also

AccessFlags

See also

FileCreationList

See also

FileAccessList

Parameters

• path – the path to the new file

• flags – HDF5 file creation flags

• fcpl – reference to a file creation property list

• fapl – reference to a file access property list

Throws

std::runtime_error – in case of a failure

Returns

new instance of File

File hdf5::file::open(const fs::path &path, AccessFlags flags = AccessFlags::READONLY, const property::FileAccessList &fapl = property::FileAccessList())

open an existing file

See also

AccessFlags

See also

FileAccessList

Parameters

• path – the path to the file to open

• flags – file open flags

• fapl – reference to a file access property list

Throws

std::runtime_error – in case of a failure

Returns

a new File instance

bool hdf5::file::is_hdf5_file(const fs::path &path)

check if the file reference by the path is an HDF5 file

Parameters

path – reference to the files path

Throws

std::runtime_error – in case of a failure

Returns

true if the path references an HDF5 file, false otherwise

Flags

enum hdf5::file::AccessFlags

flags controlling file opening and creation

Values:

enumerator TRUNCATE

enumerator EXCLUSIVE

enumerator READWRITE

enumerator READONLY

AccessFlagsBase hdf5::file::operator|(const AccessFlags &lhs, const AccessFlags &rhs)

std::ostream &hdf5::file::operator<<(std::ostream &stream, const AccessFlags &flags)

enum hdf5::file::SearchFlags

flags controlling object search in a file

Values:

enumerator FILE

enumerator DATASET

enumerator GROUP

enumerator DATATYPE

enumerator ATTRIBUTE

enumerator ALL

enumerator LOCAL

SearchFlagsBase hdf5::file::operator|(const SearchFlags &lhs, const SearchFlags &rhs)

std::ostream &hdf5::file::operator<<(std::ostream &stream, const SearchFlags &flags)

enum hdf5::file::Scope

file scope

Values:

enumerator LOCAL

enumerator GLOBAL

std::ostream &hdf5::file::operator<<(std::ostream &stream, const Scope &scope)

Driver classes

Driver

class hdf5::file::Driver

abstract class for file drivers

Driver classes in h5cpp do not hold a real reference to a driver object. They rather store information about how to setup the driver. This is mainly due to the fact that we are currently accessing the drivers only via the file access property list.

Subclassed by hdf5::file::MemoryDriver, hdf5::file::PosixDriver

Public Types

using UniquePointer = std::unique_ptr<Driver>

unique pointer type

Public Functions

virtual void operator()(const hdf5::property::FileAccessList &fapl) const = 0

set a driver

Sets a driver to a particular file access property list.

virtual DriverID id() const noexcept = 0

get driver ID

Return the ID of a particular driver.

enum hdf5::file::DriverID

enumeration to determine the file driver

Values:

enumerator ePosix

enumerator eDirect

enumerator eMemory

enumerator eMPI

PosixDriver

class hdf5::file::PosixDriver : public hdf5::file::Driver

Public Functions

virtual void operator()(const property::FileAccessList &fapl) const

set a driver

Sets a driver to a particular file access property list.

virtual DriverID id() const noexcept

get driver ID

Return the ID of a particular driver.

MemoryDriver

class hdf5::file::MemoryDriver : public hdf5::file::Driver

memory file driver

Using this driver HDF5 writes the file not to disk but in memory which can reduce the overhead from disk IO. If backing_store option is enabled the file will be written to disk with the same file name used to create the file in memory.

Public Functions

MemoryDriver() noexcept

default constructor

Sets the increment to 1MByte and backing store to false.

MemoryDriver(size_t increment, bool backing_store) noexcept

constructor

Parameters

• increment – number of bytes used to increment the memory buffer if it runs out of storage

• backing_store – enable disk storage after file close

MemoryDriver(const MemoryDriver&) = default

copy constructor

Use the default implementation here.

bool backing_store() const noexcept

get backing store status

void backing_store(bool value) noexcept

set backing store status

size_t increment() const noexcept

get increment value

void increment(size_t value)

set increment

virtual void operator()(const property::FileAccessList &fapl) const

set a driver

Sets a driver to a particular file access property list.

virtual DriverID id() const noexcept

get driver ID

Return the ID of a particular driver.