Class cv::FileNode#

File Storage Node class. View details

#include <opencv2/core/persistence.hpp>

Collaboration diagram for cv::FileNode:

Public Types#

type of the file storage node

enum cv::FileNode {
    cv::NONE = 0,
    cv::INT = 1,
    cv::REAL = 2,
    cv::FLOAT = REAL,
    cv::STR = 3,
    cv::STRING = STR,
    cv::SEQ = 4,
    cv::MAP = 5,
    cv::TYPE_MASK = 7,
    cv::FLOW = 8,
    cv::UNIFORM = 8,
    cv::EMPTY = 16,
    cv::NAMED = 32
}

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/tutorial_code/core/file_input_output/file_input_output.cpp, and samples/dnn/classification.cpp.

Member Enumeration Documentation#

enum FileNode

type of the file storage node

`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()#

cv::FileNode::FileNode()

Python:

cv.FileNode() -> <FileNode object>

The constructors.

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

FileNode()#

cv::FileNode::FileNode(const FileNode & node)

Python:

cv.FileNode() -> <FileNode object>

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()#

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

Python:

cv.FileNode() -> <FileNode object>

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

FileNode()#

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

Python:

cv.FileNode() -> <FileNode object>

Member Function Documentation#

begin()#

FileNodeIterator cv::FileNode::begin()

returns iterator pointing to the first node element

empty()#

bool cv::FileNode::empty()

Python:

cv.FileNode.empty() -> retval

returns true if the node is empty

end()#

FileNodeIterator cv::FileNode::end()

returns iterator pointing to the element following the last node element

isInt()#

bool cv::FileNode::isInt()

Python:

cv.FileNode.isInt() -> retval

returns true if the node is an integer

isMap()#

bool cv::FileNode::isMap()

Python:

cv.FileNode.isMap() -> retval

returns true if the node is a mapping

isNamed()#

bool cv::FileNode::isNamed()

Python:

cv.FileNode.isNamed() -> retval

returns true if the node has a name

isNone()#

bool cv::FileNode::isNone()

Python:

cv.FileNode.isNone() -> retval

returns true if the node is a “none” object

isReal()#

bool cv::FileNode::isReal()

Python:

cv.FileNode.isReal() -> retval

returns true if the node is a floating-point number

isSeq()#

bool cv::FileNode::isSeq()

Python:

cv.FileNode.isSeq() -> retval

returns true if the node is a sequence

isString()#

bool cv::FileNode::isString()

Python:

cv.FileNode.isString() -> retval

returns true if the node is a text string

keys()#

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

Python:

cv.FileNode.keys() -> retval

Returns keys of a mapping node.

Returns

Keys of a mapping node.

mat()#

Mat cv::FileNode::mat()

Python:

cv.FileNode.mat() -> retval

Simplified reading API to use with bindings.

name()#

std::string cv::FileNode::name()

Python:

cv.FileNode.name() -> retval

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

operator double()#

cv::FileNode::operator double()

returns the node content as double

operator float()#

cv::FileNode::operator float()

returns the node content as float

operator int64_t()#

cv::FileNode::operator int64_t()

returns the node content as a signed 64bit integer. If the node stores floating-point number, it is rounded.

operator std::string()#

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

returns the node content as text string

Here is the call graph for this function:

operator=()#

FileNode & cv::FileNode::operator=(const FileNode & node)

operator #

FileNode cv::FileNode::operator[](const char * nodename)

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 #

FileNode cv::FileNode::operator[](const String & nodename)

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 #

FileNode cv::FileNode::operator[](int i)

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.

ptr()#

uchar * cv::FileNode::ptr()

ptr()#

const uchar * cv::FileNode::ptr()

rawSize()#

size_t cv::FileNode::rawSize()

Python:

cv.FileNode.rawSize() -> retval

returns raw size of the FileNode in bytes

readRaw()#

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

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()

Python:

cv.FileNode.real() -> retval

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()#

size_t cv::FileNode::size()

Python:

cv.FileNode.size() -> retval

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

string()#

std::string cv::FileNode::string()

Python:

cv.FileNode.string() -> retval

Simplified reading API to use with bindings.

type()#

int cv::FileNode::type()

Python:

cv.FileNode.type() -> retval

Returns type of the node.

Returns

Type of the node. See FileNode::Type

isCollection()#

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

isEmptyCollection()#

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

isFlow()#

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

isMap()#

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

Python:

cv.FileNode.isMap() -> retval

isSeq()#

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

Python:

cv.FileNode.isSeq() -> retval

Member Data Documentation#

blockIdx#

size_t cv::FileNode::blockIdx

fs#

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

ofs#

size_t cv::FileNode::ofs

Source file#

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

opencv2/core/persistence.hpp

Class cv::FileNode#

Public Types#

Detailed Description#

Member Enumeration Documentation#

enum FileNode

Constructor & Destructor Documentation#

FileNode()#

FileNode()#

FileNode()#

FileNode()#

Member Function Documentation#

begin()#

empty()#

end()#

isInt()#

isMap()#

isNamed()#

isNone()#

isReal()#

isSeq()#

isString()#

keys()#

mat()#

name()#

operator double()#

operator float()#

operator int64_t()#

operator std::string()#

operator=()#

operator#

operator#

operator#

ptr()#

ptr()#

rawSize()#

readRaw()#

real()#

setValue()#

size()#

string()#

type()#

isCollection()#

isEmptyCollection()#

isFlow()#

isMap()#

isSeq()#

Member Data Documentation#

blockIdx#

fs#

ofs#

Source file#

operator #

operator #

operator #