XML/YAML/JSON file storage class that encapsulates all the information necessary for writing or reading data to/from a file. More...

#include <persistence.hpp>

Public Types
enum	Mode { READ = 0, WRITE = 1, APPEND = 2, MEMORY = 4, FORMAT_MASK = (7<<3), FORMAT_AUTO = 0, FORMAT_XML = (1<<3), FORMAT_YAML = (2<<3), FORMAT_JSON = (3<<3), BASE64 = 64, WRITE_BASE64 = BASE64 \| WRITE }
	file storage mode More...
Public Member Functions
CV_WRAP	FileStorage ()
	The constructors.
CV_WRAP	FileStorage (const String &source, int flags, const String &encoding=String())
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
	FileStorage (CvFileStorage *fs, bool owning=true)
virtual	~FileStorage ()
	the destructor. calls release()
virtual CV_WRAP bool	open (const String &filename, int flags, const String &encoding=String())
	Opens a file.
virtual CV_WRAP bool	isOpened () const
	Checks whether the file is opened.
virtual CV_WRAP void	release ()
	Closes the file and releases all the memory buffers.
virtual CV_WRAP String	releaseAndGetString ()
	Closes the file and releases all the memory buffers.
CV_WRAP FileNode	getFirstTopLevelNode () const
	Returns the first element of the top-level mapping.
CV_WRAP FileNode	root (int streamidx=0) const
	Returns the top-level mapping.
FileNode	operator[] (const String &nodename) const
	Returns the specified element of the top-level mapping.
	CV_WRAP_AS (getNode) FileNode operator[](const char *nodename) const
CvFileStorage *	operator* ()
	Returns the obsolete C FileStorage structure.
const CvFileStorage *	operator* () const
void	writeRaw (const String &fmt, const uchar *vec, size_t len)
	Writes multiple numbers.
void	writeObj (const String &name, const void *obj)
	Writes the registered C structure (CvMat, CvMatND, CvSeq).
CV_WRAP void	write (const String &name, double val)
	Simplified writing API to use with bindings.
CV_WRAP void	write (const String &name, const String &val)
CV_WRAP void	write (const String &name, InputArray val)
CV_WRAP void	writeComment (const String &comment, bool append=false)
	Writes a comment.
Static Public Member Functions
static String	getDefaultObjectName (const String &filename)
	Returns the normalized object name for the specified name of a file.
Data Fields
Ptr< CvFileStorage >	fs
	the underlying C FileStorage structure
String	elname
	the currently written element
std::vector< char >	structs
	the stack of written structures
int	state
	the writer state
Related Functions
(Note that these are not member functions.)
CV_EXPORTS FileStorage &	operator<< (FileStorage &fs, const String &str)
	Writes string to a file storage.



template<typename _Tp >
static FileStorage &	operator<< (FileStorage &fs, const _Tp &value)
	Writes data to a file storage.
static FileStorage &	operator<< (FileStorage &fs, const char *str)
	Writes data to a file storage.
static FileStorage &	operator<< (FileStorage &fs, char *value)
	Writes data to a file storage.

Detailed Description

XML/YAML/JSON file storage class that encapsulates all the information necessary for writing or reading data to/from a file.

Definition at line 302 of file persistence.hpp.

Member Enumeration Documentation

enum Mode

file storage mode

Enumerator:

READ	value, open the file for reading
WRITE	value, open the file for writing
APPEND	value, open the file for appending
MEMORY	flag, read data from source or write data to the internal buffer (which is returned by FileStorage::release)
FORMAT_MASK	mask for format flags
FORMAT_AUTO	flag, auto format
FORMAT_XML	flag, XML format
FORMAT_YAML	flag, YAML format
FORMAT_JSON	flag, JSON format
BASE64	flag, write rawdata in Base64 by default. (consider using WRITE_BASE64)
WRITE_BASE64	flag, enable both WRITE and BASE64

Definition at line 306 of file persistence.hpp.

Constructor & Destructor Documentation

CV_WRAP FileStorage ( )

The constructors.

The full constructor opens the file. Alternatively you can use the default constructor and then call FileStorage::open.

CV_WRAP FileStorage	(	const String &	source,
		int	flags,
		const String &	encoding = `String()`
	)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters:

source	Name of the file to open or the text string to read the data from. Extension of the file (.xml, .yml/.yaml, or .json) determines its format (XML, YAML or JSON respectively). Also you can append .gz to work with compressed files, for example myHugeMatrix.xml.gz. If both FileStorage::WRITE and FileStorage::MEMORY flags are specified, source is used just to specify the output file format (e.g. mydata.xml, .yml etc.).
flags	Mode of operation. See FileStorage::Mode
encoding	Encoding of the file. Note that UTF-16 XML encoding is not supported currently and you should use 8-bit encoding instead of it.

FileStorage	(	CvFileStorage *	fs,
		bool	owning = `true`
	)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

virtual ~FileStorage ( ) [virtual]

the destructor. calls release()

Member Function Documentation

CV_WRAP_AS ( getNode ) const

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

static String getDefaultObjectName ( const String & filename ) [static]

Returns the normalized object name for the specified name of a file.

Parameters:

filename Name of a file

Returns:: The normalized object name.

CV_WRAP FileNode getFirstTopLevelNode ( ) const

Returns the first element of the top-level mapping.

Returns:: The first element of the top-level mapping.

virtual CV_WRAP bool isOpened ( ) const [virtual]

Checks whether the file is opened.

Returns:: true if the object is associated with the current file and false otherwise. It is a good practice to call this method after you tried to open a file.

virtual CV_WRAP bool open	(	const String &	filename,
		int	flags,
		const String &	encoding = `String()`
	)		`[virtual]`

Opens a file.

See description of parameters in FileStorage::FileStorage. The method calls FileStorage::release before opening the file.

Parameters:

filename	Name of the file to open or the text string to read the data from. Extension of the file (.xml, .yml/.yaml or .json) determines its format (XML, YAML or JSON respectively). Also you can append .gz to work with compressed files, for example myHugeMatrix.xml.gz. If both FileStorage::WRITE and FileStorage::MEMORY flags are specified, source is used just to specify the output file format (e.g. mydata.xml, .yml etc.). A file name can also contain parameters. You can use this format, "*?base64" (e.g. "file.json?base64" (case sensitive)), as an alternative to FileStorage::BASE64 flag.
flags	Mode of operation. One of FileStorage::Mode
encoding	Encoding of the file. Note that UTF-16 XML encoding is not supported currently and you should use 8-bit encoding instead of it.

CvFileStorage* operator* ( )

Returns the obsolete C FileStorage structure.

Returns:: Pointer to the underlying C FileStorage structure

Definition at line 416 of file persistence.hpp.

const CvFileStorage* operator* ( ) const

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Definition at line 419 of file persistence.hpp.

FileNode operator[] ( const String & nodename ) const

Returns the specified element of the top-level mapping.

Parameters:

nodename Name of the file node.

Returns:: Node with the given name.

virtual CV_WRAP void release ( ) [virtual]

Closes the file and releases all the memory buffers.

Call this method after all I/O operations with the storage are finished.

virtual CV_WRAP String releaseAndGetString ( ) [virtual]

Closes the file and releases all the memory buffers.

Call this method after all I/O operations with the storage are finished. If the storage was opened for writing data and FileStorage::WRITE was specified

CV_WRAP FileNode root ( int streamidx = 0 ) const

Returns the top-level mapping.

Parameters:

streamidx Zero-based index of the stream. In most cases there is only one stream in the file. However, YAML supports multiple streams and so there can be several.

Returns:: The top-level mapping.

CV_WRAP void write	(	const String &	name,
		const String &	val
	)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

CV_WRAP void write	(	const String &	name,
		double	val
	)

Simplified writing API to use with bindings.

Parameters:

name	Name of the written object
val	Value of the written object

CV_WRAP void write	(	const String &	name,
		InputArray	val
	)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

CV_WRAP void writeComment	(	const String &	comment,
		bool	append = `false`
	)

Writes a comment.

The function writes a comment into file storage. The comments are skipped when the storage is read.

Parameters:

comment	The written comment, single-line or multi-line
append	If true, the function tries to put the comment at the end of current line. Else if the comment is multi-line, or if it does not fit at the end of the current line, the comment starts a new line.

void writeObj	(	const String &	name,
		const void *	obj
	)

Writes the registered C structure (CvMat, CvMatND, CvSeq).

Parameters:

name	Name of the written object.
obj	Pointer to the object.

See also:: ocvWrite for details.

void writeRaw	(	const String &	fmt,
		const uchar *	vec,
		size_t	len
	)

Writes multiple numbers.

Writes one or more numbers of the specified format to the currently written structure. Usually it is more convenient to use operator `<<` instead of this method.

Parameters:

fmt	Specification of each array element, see format specification
vec	Pointer to the written array.
len	Number of the uchar elements to write.

Friends And Related Function Documentation

CV_EXPORTS FileStorage & operator<<	(	FileStorage &	fs,
		const String &	str
	)		`[related]`

Writes string to a file storage.

static FileStorage & operator<<	(	FileStorage &	fs,
		const _Tp &	value
	)		`[related]`

Writes data to a file storage.

Definition at line 1107 of file persistence.hpp.

static FileStorage & operator<<	(	FileStorage &	fs,
		const char *	str
	)		`[related]`

Writes data to a file storage.

Definition at line 1122 of file persistence.hpp.

static FileStorage & operator<<	(	FileStorage &	fs,
		char *	value
	)		`[related]`

Writes data to a file storage.

Definition at line 1130 of file persistence.hpp.

Field Documentation

String elname

the currently written element

Definition at line 466 of file persistence.hpp.

Ptr<CvFileStorage> fs

the underlying C FileStorage structure

Definition at line 465 of file persistence.hpp.

int state

the writer state

Definition at line 468 of file persistence.hpp.

std::vector<char> structs

the stack of written structures

Definition at line 467 of file persistence.hpp.

Type:	Library
Created:	29 Jan 2021
Imports:	11
Forks:	0
Commits:	1
Dependents:	1
Dependencies:	0
Followers:	60

Important changes to repositories hosted on mbed.com

FileStorage Class Reference
[XML/YAML Persistence]

Public Types

Public Member Functions

Static Public Member Functions

Data Fields

Related Functions

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation

Friends And Related Function Documentation

Field Documentation

Repository toolbox

Repository details

Important Information for this Arm website

Important changes to repositories hosted on mbed.com

FileStorage Class Reference [XML/YAML Persistence]

Public Types

Public Member Functions

Static Public Member Functions

Data Fields

Related Functions

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation

Friends And Related Function Documentation

Field Documentation

Repository toolbox

Repository details

Important Information for this Arm website

Access Warning

FileStorage Class Reference
[XML/YAML Persistence]