cv::FileNode Class Reference

File Storage Node class. More...

#include <opencv2/core/persistence.hpp>

Public Types
enum	Type {   NONE = 0,   INT = 1,   REAL = 2,   FLOAT = REAL,   STR = 3,   STRING = STR,   REF = 4,   SEQ = 5,   MAP = 6,   TYPE_MASK = 7,   FLOW = 8,   USER = 16,   EMPTY = 32,   NAMED = 64 }
	type of the file storage node More...

Public Member Functions
	FileNode ()
	The constructors. More...
	FileNode (const CvFileStorage *fs, const CvFileNode *node)
	FileNode (const FileNode &node)
FileNodeIterator	begin () const
	returns iterator pointing to the first node element More...
bool	empty () const
	returns true if the node is empty More...
FileNodeIterator	end () const
	returns iterator pointing to the element following the last node element More...
bool	isInt () const
	returns true if the node is an integer More...
bool	isMap () const
	returns true if the node is a mapping More...
bool	isNamed () const
	returns true if the node has a name More...
bool	isNone () const
	returns true if the node is a "none" object More...
bool	isReal () const
	returns true if the node is a floating-point number More...
bool	isSeq () const
	returns true if the node is a sequence More...
bool	isString () const
	returns true if the node is a text string More...
std::vector< String >	keys () const
	Returns keys of a mapping node. More...
Mat	mat () const
	Simplified reading API to use with bindings. More...
String	name () const
	returns the node name or an empty string if the node is nameless More...
	operator double () const
	returns the node content as double More...
	operator float () const
	returns the node content as float More...
	operator std::string () const
	operator String () const
	returns the node content as text string More...
CvFileNode *	operator* ()
	returns pointer to the underlying file node More...
const CvFileNode *	operator* () const
	returns pointer to the underlying file node More...
FileNode &	operator= (const FileNode &node)
FileNode	operator[] (const String &nodename) const
	Returns element of a mapping node or a sequence node. More...
FileNode	operator[] (const char *nodename) const
FileNode	operator[] (int i) const
void *	readObj () const
	reads the registered object and returns pointer to it More...
void	readRaw (const String &fmt, uchar *vec, size_t len) const
	Reads node elements to the buffer with the specified format. More...
double	real () const
	Simplified reading API to use with bindings. More...
size_t	size () const
	returns the number of elements in the node, if it is a sequence or mapping, or 1 otherwise. More...
String	string () const
	Simplified reading API to use with bindings. More...
int	type () const
	Returns type of the node. More...

Public Attributes
const CvFileStorage *	fs
const CvFileNode *	node

Related Functions
(Note that these are not member functions.)
void	read (const FileNode &node, int &value, int default_value)
void	read (const FileNode &node, float &value, float default_value)
void	read (const FileNode &node, double &value, double default_value)
void	read (const FileNode &node, String &value, const String &default_value)
void	read (const FileNode &node, std::string &value, const std::string &default_value)
void	read (const FileNode &node, Mat &mat, const Mat &default_mat=Mat())
void	read (const FileNode &node, SparseMat &mat, const SparseMat &default_mat=SparseMat())
void	read (const FileNode &node, KeyPoint &value, const KeyPoint &default_value)
void	read (const FileNode &node, DMatch &value, const DMatch &default_value)
template<typename _Tp >
static void	read (const FileNode &node, Point_< _Tp > &value, const Point_< _Tp > &default_value)
template<typename _Tp >
static void	read (const FileNode &node, Point3_< _Tp > &value, const Point3_< _Tp > &default_value)
template<typename _Tp >
static void	read (const FileNode &node, Size_< _Tp > &value, const Size_< _Tp > &default_value)
template<typename _Tp >
static void	read (const FileNode &node, Complex< _Tp > &value, const Complex< _Tp > &default_value)
template<typename _Tp >
static void	read (const FileNode &node, Rect_< _Tp > &value, const Rect_< _Tp > &default_value)
template<typename _Tp , int cn>
static void	read (const FileNode &node, Vec< _Tp, cn > &value, const Vec< _Tp, cn > &default_value)
template<typename _Tp >
static void	read (const FileNode &node, Scalar_< _Tp > &value, const Scalar_< _Tp > &default_value)
static void	read (const FileNode &node, Range &value, const Range &default_value)
static void	read (const FileNode &node, bool &value, bool default_value)
static void	read (const FileNode &node, uchar &value, uchar default_value)
static void	read (const FileNode &node, schar &value, schar default_value)
static void	read (const FileNode &node, ushort &value, ushort default_value)
static void	read (const FileNode &node, short &value, short default_value)
template<typename _Tp >
static void	read (FileNodeIterator &it, std::vector< _Tp > &vec, size_t maxCount=(size_t) INT_MAX)
template<typename _Tp >
static void	read (const FileNode &node, std::vector< _Tp > &vec, const std::vector< _Tp > &default_value=std::vector< _Tp >())
static void	read (const FileNode &node, std::vector< KeyPoint > &vec, const std::vector< KeyPoint > &default_value)
static void	read (const FileNode &node, std::vector< DMatch > &vec, const std::vector< DMatch > &default_value)
template<typename _Tp >
static void	operator>> (const FileNode &n, _Tp &value)
	Reads data from a file storage. More...
template<typename _Tp >
static void	operator>> (const FileNode &n, std::vector< _Tp > &vec)
	Reads data from a file storage. More...
static void	operator>> (const FileNode &n, KeyPoint &kpt)
	Reads KeyPoint from a file storage. More...
static void	operator>> (const FileNode &n, DMatch &m)
	Reads DMatch from a file storage. More...

Detailed Description

File Storage Node class.

The node is used to store each and every element of the file storage opened for reading. When XML/YAML file is read, it is first parsed and stored in the memory as a hierarchical collection of nodes. Each node can be a "leaf" that is contain a single number or a string, or be a collection of other nodes. There can be named collections (mappings) where each element has a name and it is accessed by a name, and ordered collections (sequences) where elements do not have names but rather accessed by index. Type of the file node can be determined using FileNode::type method.

Note that file nodes are only used for navigating file storages opened for reading. When a file storage is opened for writing, no data is stored in memory after it is written.

Examples:

samples/cpp/filestorage.cpp.

Member Enumeration Documentation

Type

enum cv::FileNode::Type

type of the file storage node

Enumerator
NONE	empty node
INT	an integer
REAL	floating-point number
FLOAT	synonym or REAL
STR	text string in UTF-8 encoding
STRING	synonym for STR
REF	integer of size size_t. Typically used for storing complex dynamic structures where some elements reference the others
SEQ	sequence
MAP	mapping
TYPE_MASK
FLOW	compact representation of a sequence or mapping. Used only by YAML writer
USER	a registered object (e.g. a matrix)
EMPTY	empty structure (sequence or mapping)
NAMED	the node has a name (i.e. it is element of a mapping)

Constructor & Destructor Documentation

FileNode() [1/3]

cv::FileNode::FileNode

(

)

The constructors.

These constructors are used to create a default file node, construct it from obsolete structures or from the another file node.

FileNode() [2/3]

cv::FileNode::FileNode	(	const CvFileStorage *	fs,
		const CvFileNode *	node
	)

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

Parameters

fs	Pointer to the obsolete file storage structure.
node	File node to be used as initialization for the created file node.

FileNode() [3/3]

cv::FileNode::FileNode

(

const FileNode &

node

)

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

Parameters

node	File node to be used as initialization for the created file node.

Member Function Documentation

begin()

FileNodeIterator cv::FileNode::begin

(

)

const

returns iterator pointing to the first node element

Examples:

samples/cpp/filestorage.cpp.

empty()

bool cv::FileNode::empty

(

)

const

Python:
	cv.FileNode.empty(		) ->	retval

returns true if the node is empty

Examples:

samples/cpp/filestorage.cpp.

end()

FileNodeIterator cv::FileNode::end

(

)

const

returns iterator pointing to the element following the last node element

Examples:

samples/cpp/filestorage.cpp.

isInt()

bool cv::FileNode::isInt

(

)

const

Python:
	cv.FileNode.isInt(		) ->	retval

returns true if the node is an integer

isMap()

bool cv::FileNode::isMap

(

)

const

Python:
	cv.FileNode.isMap(		) ->	retval

returns true if the node is a mapping

isNamed()

bool cv::FileNode::isNamed

(

)

const

Python:
	cv.FileNode.isNamed(		) ->	retval

returns true if the node has a name

isNone()

bool cv::FileNode::isNone

(

)

const

Python:
	cv.FileNode.isNone(		) ->	retval

returns true if the node is a "none" object

isReal()

bool cv::FileNode::isReal

(

)

const

Python:
	cv.FileNode.isReal(		) ->	retval

returns true if the node is a floating-point number

isSeq()

bool cv::FileNode::isSeq

(

)

const

Python:
	cv.FileNode.isSeq(		) ->	retval

returns true if the node is a sequence

isString()

bool cv::FileNode::isString

(

)

const

Python:
	cv.FileNode.isString(		) ->	retval

returns true if the node is a text string

keys()

std::vector<String> cv::FileNode::keys

(

)

const

Python:
	cv.FileNode.keys(		) ->	retval

Returns keys of a mapping node.

Returns

Keys of a mapping node.

mat()

Mat cv::FileNode::mat

(

)

const

Python:
	cv.FileNode.mat(		) ->	retval

Simplified reading API to use with bindings.

name()

String cv::FileNode::name

(

)

const

Python:
	cv.FileNode.name(		) ->	retval

returns the node name or an empty string if the node is nameless

operator double()

cv::FileNode::operator double

(

)

const

returns the node content as double

operator float()

cv::FileNode::operator float

(

)

const

returns the node content as float

operator std::string()

cv::FileNode::operator std::string

(

)

const

operator String()

cv::FileNode::operator String

(

)

const

returns the node content as text string

operator*() [1/2]

CvFileNode* cv::FileNode::operator*

(

)

returns pointer to the underlying file node

operator*() [2/2]

const CvFileNode* cv::FileNode::operator*

(

)

const

returns pointer to the underlying file node

operator=()

FileNode& cv::FileNode::operator=

(

const FileNode &

node

)

operator[]() [1/3]

FileNode cv::FileNode::operator[]

(

const String &

nodename

)

const

Python:
	cv.FileNode.at(	i	) ->	retval
	cv.FileNode.getNode(	nodename	) ->	retval

Returns element of a mapping node or a sequence node.

Parameters

nodename

Name of an element in the mapping node.

Returns

Returns the element with the given identifier.

operator[]() [2/3]

FileNode cv::FileNode::operator[]

(

const char *

nodename

)

const

Python:
	cv.FileNode.at(	i	) ->	retval
	cv.FileNode.getNode(	nodename	) ->	retval

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

Parameters

nodename

Name of an element in the mapping node.

operator[]() [3/3]

FileNode cv::FileNode::operator[]

(

int

i

)

const

Python:
	cv.FileNode.at(	i	) ->	retval
	cv.FileNode.getNode(	nodename	) ->	retval

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

Parameters

i	Index of an element in the sequence node.

readObj()

void* cv::FileNode::readObj

(

)

const

reads the registered object and returns pointer to it

readRaw()

void cv::FileNode::readRaw	(	const String &	fmt,
		uchar *	vec,
		size_t	len
	)		const

Reads node elements to the buffer with the specified format.

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 destination array.
len	Number of bytes to read (buffer size limit). If it is greater than number of remaining elements then all of them will be read.

real()

double cv::FileNode::real

(

)

const

Python:
	cv.FileNode.real(		) ->	retval

Simplified reading API to use with bindings.

size()

size_t cv::FileNode::size

(

)

const

Python:
	cv.FileNode.size(		) ->	retval

returns the number of elements in the node, if it is a sequence or mapping, or 1 otherwise.

string()

String cv::FileNode::string

(

)

const

Python:
	cv.FileNode.string(		) ->	retval

Simplified reading API to use with bindings.

type()

int cv::FileNode::type

(

)

const

Python:
	cv.FileNode.type(		) ->	retval

Returns type of the node.

Returns

Type of the node. See FileNode::Type

Examples:

samples/cpp/filestorage.cpp.

Friends And Related Function Documentation

operator>>() [1/4]

template<typename _Tp >

static void operator>> ( const FileNode &  n, _Tp &  value  )

related

Reads data from a file storage.

operator>>() [2/4]

template<typename _Tp >

static void operator>> ( const FileNode &  n, std::vector< _Tp > &  vec  )

related

Reads data from a file storage.

operator>>() [3/4]

static void operator>> ( const FileNode &  n, KeyPoint &  kpt  )

related

Reads KeyPoint from a file storage.

operator>>() [4/4]

static void operator>> ( const FileNode &  n, DMatch &  m  )

related

Reads DMatch from a file storage.

read() [1/26]

void read ( const FileNode &  node, int &  value, int  default_value  )

related

read() [2/26]

void read ( const FileNode &  node, float &  value, float  default_value  )

related

read() [3/26]

void read ( const FileNode &  node, double &  value, double  default_value  )

related

read() [4/26]

void read ( const FileNode &  node, String &  value, const String &  default_value  )

related

read() [5/26]

void read ( const FileNode &  node, std::string &  value, const std::string &  default_value  )

related

read() [6/26]

void read ( const FileNode &  node, Mat &  mat, const Mat &  default_mat = Mat()  )

related

read() [7/26]

void read ( const FileNode &  node, SparseMat &  mat, const SparseMat &  default_mat = SparseMat()  )

related

read() [8/26]

void read ( const FileNode &  node, KeyPoint &  value, const KeyPoint &  default_value  )

related

read() [9/26]

void read ( const FileNode &  node, DMatch &  value, const DMatch &  default_value  )

related

read() [10/26]

template<typename _Tp >

static void read ( const FileNode &  node, Point_< _Tp > &  value, const Point_< _Tp > &  default_value  )

related

read() [11/26]

template<typename _Tp >

static void read ( const FileNode &  node, Point3_< _Tp > &  value, const Point3_< _Tp > &  default_value  )

related

read() [12/26]

template<typename _Tp >

static void read ( const FileNode &  node, Size_< _Tp > &  value, const Size_< _Tp > &  default_value  )

related

read() [13/26]

template<typename _Tp >

static void read ( const FileNode &  node, Complex< _Tp > &  value, const Complex< _Tp > &  default_value  )

related

read() [14/26]

template<typename _Tp >

static void read ( const FileNode &  node, Rect_< _Tp > &  value, const Rect_< _Tp > &  default_value  )

related

read() [15/26]

template<typename _Tp , int cn>

static void read ( const FileNode &  node, Vec< _Tp, cn > &  value, const Vec< _Tp, cn > &  default_value  )

related

read() [16/26]

template<typename _Tp >

static void read ( const FileNode &  node, Scalar_< _Tp > &  value, const Scalar_< _Tp > &  default_value  )

related

read() [17/26]

static void read ( const FileNode &  node, Range &  value, const Range &  default_value  )

related

read() [18/26]

static void read ( const FileNode &  node, bool &  value, bool  default_value  )

related

read() [19/26]

static void read ( const FileNode &  node, uchar &  value, uchar  default_value  )

related

read() [20/26]

static void read ( const FileNode &  node, schar &  value, schar  default_value  )

related

read() [21/26]

static void read ( const FileNode &  node, ushort &  value, ushort  default_value  )

related

read() [22/26]

static void read ( const FileNode &  node, short &  value, short  default_value  )

related

read() [23/26]

template<typename _Tp >

static void read ( FileNodeIterator &  it, std::vector< _Tp > &  vec, size_t  maxCount = (size_t)INT_MAX  )

related

read() [24/26]

template<typename _Tp >

static void read ( const FileNode &  node, std::vector< _Tp > &  vec, const std::vector< _Tp > &  default_value = std::vector<_Tp>()  )

related

read() [25/26]

static void read ( const FileNode &  node, std::vector< KeyPoint > &  vec, const std::vector< KeyPoint > &  default_value  )

related

read() [26/26]

static void read ( const FileNode &  node, std::vector< DMatch > &  vec, const std::vector< DMatch > &  default_value  )

related

Member Data Documentation

fs

const CvFileStorage* cv::FileNode::fs

node

const CvFileNode* cv::FileNode::node

---

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

• opencv2/core/persistence.hpp