cv::FileNode Class Reference

File Storage Node class. More...

#include <persistence.hpp>

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

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

Static Public Member Functions
static bool	isMap (int flags)
static bool	isSeq (int flags)
static bool	isCollection (int flags)
static bool	isEmptyCollection (int flags)
static bool	isFlow (int flags)

Public Attributes
FileStorage::Impl *	fs
size_t	blockIdx
size_t	ofs

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.

Member Enumeration Documentation

anonymous enum

anonymous enum

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
SEQ	sequence
MAP	mapping
TYPE_MASK
FLOW	compact representation of a sequence or mapping. Used only by YAML writer
UNIFORM	UNIFORM is used only when reading FileStorage; FLOW is used only when writing. So they share the same bit. if set, means that all the collection elements are numbers of the same type (real's or int's).
EMPTY	empty structure (sequence or mapping)
NAMED	the node has a name (i.e. it is element of a mapping).

Constructor & Destructor Documentation

FileNode() [1/4]

CV_WRAP 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() [2/4]

cv::FileNode::FileNode	(	const FileStorage *	fs,
		size_t	blockIdx,
		size_t	ofs
	)

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 file storage structure.
blockIdx	Index of the memory block where the file node is stored
ofs	Offset in bytes from the beginning of the serialized storage

Deprecated:

FileNode() [3/4]

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.

FileNode() [4/4]

cv::FileNode::FileNode	(	FileStorage::Impl *	fs,
		size_t	blockIdx,
		size_t	ofs
	)

Member Function Documentation

begin()

FileNodeIterator cv::FileNode::begin

(

)

const

returns iterator pointing to the first node element

CV_WRAP_AS() [1/2]

cv::FileNode::CV_WRAP_AS

(

at

)

const

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.

CV_WRAP_AS() [2/2]

cv::FileNode::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.

Parameters

nodename

Name of an element in the mapping node.

empty()

CV_WRAP bool cv::FileNode::empty

(

)

const

returns true if the node is empty

end()

FileNodeIterator cv::FileNode::end

(

)

const

returns iterator pointing to the element following the last node element

isCollection()

static bool cv::FileNode::isCollection ( int  flags )

static

isEmptyCollection()

static bool cv::FileNode::isEmptyCollection ( int  flags )

static

isFlow()

static bool cv::FileNode::isFlow ( int  flags )

static

isInt()

CV_WRAP bool cv::FileNode::isInt

(

)

const

returns true if the node is an integer

isMap() [1/2]

CV_WRAP bool cv::FileNode::isMap

(

)

const

returns true if the node is a mapping

isMap() [2/2]

static bool cv::FileNode::isMap ( int  flags )

static

isNamed()

CV_WRAP bool cv::FileNode::isNamed

(

)

const

returns true if the node has a name

isNone()

CV_WRAP bool cv::FileNode::isNone

(

)

const

returns true if the node is a "none" object

isReal()

CV_WRAP bool cv::FileNode::isReal

(

)

const

returns true if the node is a floating-point number

isSeq() [1/2]

CV_WRAP bool cv::FileNode::isSeq

(

)

const

returns true if the node is a sequence

isSeq() [2/2]

static bool cv::FileNode::isSeq ( int  flags )

static

isString()

CV_WRAP bool cv::FileNode::isString

(

)

const

returns true if the node is a text string

keys()

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

(

)

const

Returns keys of a mapping node.

Returns

Keys of a mapping node.

mat()

CV_WRAP Mat cv::FileNode::mat

(

)

const

Simplified reading API to use with bindings.

name()

CV_WRAP std::string cv::FileNode::name

(

)

const

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 int()

cv::FileNode::operator int

(

)

const

returns the node content as an integer. If the node stores floating-point number, it is rounded.

operator std::string()

cv::FileNode::operator std::string ( ) const

inline

returns the node content as text string

operator=()

FileNode& cv::FileNode::operator=

(

const FileNode &

node

)

operator[]()

FileNode cv::FileNode::operator[]

(

const String &

nodename

)

const

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.

ptr() [1/2]

uchar* cv::FileNode::ptr

(

)

ptr() [2/2]

const uchar* cv::FileNode::ptr

(

)

const

rawSize()

CV_WRAP size_t cv::FileNode::rawSize

(

)

const

returns raw size of the FileNode in bytes

readRaw()

void cv::FileNode::readRaw	(	const String &	fmt,
		void *	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()

CV_WRAP double cv::FileNode::real

(

)

const

Simplified reading API to use with bindings.

setValue()

void cv::FileNode::setValue	(	int	type,
		const void *	value,
		int	len = -1
	)

Internal method used when reading FileStorage. Sets the type (int, real or string) and value of the previously created node.

size()

CV_WRAP size_t cv::FileNode::size

(

)

const

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

string()

CV_WRAP std::string cv::FileNode::string

(

)

const

Simplified reading API to use with bindings.

type()

CV_WRAP int cv::FileNode::type

(

)

const

Returns type of the node.

Returns

Type of the node. See FileNode::Type

Member Data Documentation

blockIdx

size_t cv::FileNode::blockIdx

fs

FileStorage::Impl* cv::FileNode::fs

ofs

size_t cv::FileNode::ofs

---

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

• build/release/_deps/opencv-src/include/opencv4/opencv2/core/persistence.hpp