RDF term (librdf_node)

RDF term (librdf_node) — RDF triple component

Synopsis

void                librdf_free_node                    (librdf_node *node);
librdf_node *       librdf_new_node                     (librdf_world *world);
librdf_node *       librdf_new_node_from_blank_identifier
                                                        (librdf_world *world,
                                                         const unsigned char *identifier);
librdf_node *       librdf_new_node_from_counted_blank_identifier
                                                        (librdf_world *world,
                                                         const unsigned char *identifier,
                                                         size_t identifier_len);
librdf_node *       librdf_new_node_from_counted_uri_string
                                                        (librdf_world *world,
                                                         const unsigned char *uri_string,
                                                         size_t len);
librdf_node *       librdf_new_node_from_literal        (librdf_world *world,
                                                         const unsigned char *string,
                                                         const char *xml_language,
                                                         int is_wf_xml);
librdf_node *       librdf_new_node_from_node           (librdf_node *node);
librdf_node *       librdf_new_node_from_normalised_uri_string
                                                        (librdf_world *world,
                                                         const unsigned char *uri_string,
                                                         librdf_uri *source_uri,
                                                         librdf_uri *base_uri);
librdf_node *       librdf_new_node_from_typed_counted_literal
                                                        (librdf_world *world,
                                                         const unsigned char *value,
                                                         size_t value_len,
                                                         const char *xml_language,
                                                         size_t xml_language_len,
                                                         librdf_uri *datatype_uri);
librdf_node *       librdf_new_node_from_typed_literal  (librdf_world *world,
                                                         const unsigned char *value,
                                                         const char *xml_language,
                                                         librdf_uri *datatype_uri);
librdf_node *       librdf_new_node_from_uri            (librdf_world *world,
                                                         librdf_uri *uri);
librdf_node *       librdf_new_node_from_uri_local_name (librdf_world *world,
                                                         librdf_uri *uri,
                                                         const unsigned char *local_name);
librdf_node *       librdf_new_node_from_uri_string     (librdf_world *world,
                                                         const unsigned char *uri_string);
typedef             librdf_node;
librdf_node *       librdf_node_decode                  (librdf_world *world,
                                                         size_t *size_p,
                                                         unsigned char *buffer,
                                                         size_t length);
size_t              librdf_node_encode                  (librdf_node *node,
                                                         unsigned char *buffer,
                                                         size_t length);
int                 librdf_node_equals                  (librdf_node *first_node,
                                                         librdf_node *second_node);
unsigned char *     librdf_node_get_blank_identifier    (librdf_node *node);
unsigned char *     librdf_node_get_counted_blank_identifier
                                                        (librdf_node *node,
                                                         size_t *len_p);
int                 librdf_node_get_li_ordinal          (librdf_node *node);
unsigned char *     librdf_node_get_literal_value       (librdf_node *node);
unsigned char *     librdf_node_get_literal_value_as_counted_string
                                                        (librdf_node *node,
                                                         size_t *len_p);
char *              librdf_node_get_literal_value_as_latin1
                                                        (librdf_node *node);
librdf_uri *        librdf_node_get_literal_value_datatype_uri
                                                        (librdf_node *node);
int                 librdf_node_get_literal_value_is_wf_xml
                                                        (librdf_node *node);
char *              librdf_node_get_literal_value_language
                                                        (librdf_node *node);
librdf_node_type    librdf_node_get_type                (librdf_node *node);
librdf_uri *        librdf_node_get_uri                 (librdf_node *node);
int                 librdf_node_is_blank                (librdf_node *node);
int                 librdf_node_is_literal              (librdf_node *node);
int                 librdf_node_is_resource             (librdf_node *node);
librdf_iterator *   librdf_node_new_static_node_iterator
                                                        (librdf_world *world,
                                                         librdf_node **nodes,
                                                         int size);
void                librdf_node_print                   (librdf_node *node,
                                                         FILE *fh);
librdf_iterator *   librdf_node_static_iterator_create  (librdf_node **nodes,
                                                         int size);
unsigned char *     librdf_node_to_counted_string       (librdf_node *node,
                                                         size_t *len_p);
unsigned char *     librdf_node_to_string               (librdf_node *node);
enum                librdf_node_type;
int                 librdf_node_write                   (librdf_node *node,
                                                         raptor_iostream *iostr);

Description

The (subject, predicate, object) parts of an RDF triple.

Details

librdf_free_node ()

void                librdf_free_node                    (librdf_node *node);

Destructor - destroy an librdf_node object.

node :

librdf_node object

librdf_new_node ()

librdf_node *       librdf_new_node                     (librdf_world *world);

Constructor - create a new librdf_node object with a private identifier.

Calls librdf_new_node_from_blank_identifier(world, NULL) to construct a new redland blank node identifier and make a new librdf_node object for it.

world :

redland world object

Returns :

a new librdf_node object or NULL on failure

librdf_new_node_from_blank_identifier ()

librdf_node *       librdf_new_node_from_blank_identifier
                                                        (librdf_world *world,
                                                         const unsigned char *identifier);

Constructor - create a new blank node librdf_node object from a blank node identifier.

If no identifier string is given (NULL) this creates a new internal identifier and uses it.

world :

redland world object

identifier :

UTF-8 encoded blank node identifier or NULL

Returns :

new librdf_node object or NULL on failure

librdf_new_node_from_counted_blank_identifier ()

librdf_node *       librdf_new_node_from_counted_blank_identifier
                                                        (librdf_world *world,
                                                         const unsigned char *identifier,
                                                         size_t identifier_len);

Constructor - create a new blank node librdf_node object from a blank node counted length identifier.

If no identifier string is given (NULL) this creates a new internal identifier and uses it.

world :

redland world object

identifier :

UTF-8 encoded blank node identifier or NULL

identifier_len :

length of identifier

Returns :

new librdf_node object or NULL on failure

librdf_new_node_from_counted_uri_string ()

librdf_node *       librdf_new_node_from_counted_uri_string
                                                        (librdf_world *world,
                                                         const unsigned char *uri_string,
                                                         size_t len);

Constructor - create a new librdf_node object from a counted URI string.

world :

redland world object

uri_string :

string representing a URI

len :

length of string

Returns :

a new librdf_node object or NULL on failure

librdf_new_node_from_literal ()

librdf_node *       librdf_new_node_from_literal        (librdf_world *world,
                                                         const unsigned char *string,
                                                         const char *xml_language,
                                                         int is_wf_xml);

Constructor - create a new literal librdf_node object.

0.9.12: xml_space argument deleted

An xml_language cannot be used when is_wf_xml is non-0. If both are given, NULL is returned. If xml_language is the empty string, it is the equivalent to NULL.

world :

redland world object

string :

literal UTF-8 encoded string value

xml_language :

literal XML language (or NULL, empty string)

is_wf_xml :

non 0 if literal is XML

Returns :

new librdf_node object or NULL on failure

librdf_new_node_from_node ()

librdf_node *       librdf_new_node_from_node           (librdf_node *node);

Copy constructor - create a new librdf_node object from an existing librdf_node object.

node :

librdf_node object to copy

Returns :

a new librdf_node object or NULL on failure

librdf_new_node_from_normalised_uri_string ()

librdf_node *       librdf_new_node_from_normalised_uri_string
                                                        (librdf_world *world,
                                                         const unsigned char *uri_string,
                                                         librdf_uri *source_uri,
                                                         librdf_uri *base_uri);

Constructor - create a new librdf_node object from a UTF-8 encoded URI string normalised to a new base URI.

world :

redland world object

uri_string :

UTF-8 encoded string representing a URI

source_uri :

source URI

base_uri :

base URI

Returns :

a new librdf_node object or NULL on failure

librdf_new_node_from_typed_counted_literal ()

librdf_node *       librdf_new_node_from_typed_counted_literal
                                                        (librdf_world *world,
                                                         const unsigned char *value,
                                                         size_t value_len,
                                                         const char *xml_language,
                                                         size_t xml_language_len,
                                                         librdf_uri *datatype_uri);

Constructor - create a new typed literal librdf_node object.

Takes copies of the passed in value, datatype_uri and xml_language.

Only one of xml_language or datatype_uri may be given. If both are given, NULL is returned. If xml_language is the empty string, it is the equivalent to NULL.

world :

redland world object

value :

literal UTF-8 encoded string value

value_len :

literal string value length

xml_language :

literal XML language (or NULL, empty string)

xml_language_len :

literal XML language length (not used if xml_language is NULL)

datatype_uri :

URI of typed literal datatype or NULL

Returns :

new librdf_node object or NULL on failure

librdf_new_node_from_typed_literal ()

librdf_node *       librdf_new_node_from_typed_literal  (librdf_world *world,
                                                         const unsigned char *value,
                                                         const char *xml_language,
                                                         librdf_uri *datatype_uri);

Constructor - create a new typed literal librdf_node object.

Only one of xml_language or datatype_uri may be given. If both are given, NULL is returned. If xml_language is the empty string, it is the equivalent to NULL.

world :

redland world object

value :

literal UTF-8 encoded string value

xml_language :

literal XML language (or NULL, empty string)

datatype_uri :

URI of typed literal datatype or NULL

Returns :

new librdf_node object or NULL on failure

librdf_new_node_from_uri ()

librdf_node *       librdf_new_node_from_uri            (librdf_world *world,
                                                         librdf_uri *uri);

Constructor - create a new resource librdf_node object with a given URI.

world :

redland world object

uri :

librdf_uri object

Returns :

a new librdf_node object or NULL on failure

librdf_new_node_from_uri_local_name ()

librdf_node *       librdf_new_node_from_uri_local_name (librdf_world *world,
                                                         librdf_uri *uri,
                                                         const unsigned char *local_name);

Constructor - create a new resource librdf_node object with a given URI and local name.

world :

redland world object

uri :

librdf_uri object

local_name :

local name to append to URI

Returns :

a new librdf_node object or NULL on failure

librdf_new_node_from_uri_string ()

librdf_node *       librdf_new_node_from_uri_string     (librdf_world *world,
                                                         const unsigned char *uri_string);

Constructor - create a new librdf_node object from a URI string.

world :

redland world object

uri_string :

string representing a URI

Returns :

a new librdf_node object or NULL on failure

librdf_node

typedef raptor_term librdf_node;

Redland node class.


librdf_node_decode ()

librdf_node *       librdf_node_decode                  (librdf_world *world,
                                                         size_t *size_p,
                                                         unsigned char *buffer,
                                                         size_t length);

Deserialise a node from a buffer.

Decodes the serialised node (as created by librdf_node_encode() ) from the given buffer.

world :

librdf_world

size_p :

pointer to bytes used or NULL

buffer :

the buffer to use

length :

buffer size

Returns :

new node or NULL on failure (bad encoding, allocation failure)

librdf_node_encode ()

size_t              librdf_node_encode                  (librdf_node *node,
                                                         unsigned char *buffer,
                                                         size_t length);

Serialise a node into a buffer.

Encodes the given node in the buffer, which must be of sufficient size. If buffer is NULL, no work is done but the size of buffer required is returned.

If the node cannot be encoded due to restrictions of the encoding format, a redland error is generated

node :

the node to serialise

buffer :

the buffer to use

length :

buffer size

Returns :

the number of bytes written or 0 on failure.

librdf_node_equals ()

int                 librdf_node_equals                  (librdf_node *first_node,
                                                         librdf_node *second_node);

Compare two librdf_node objects for equality.

Note - for literal nodes, XML language, XML space and well-formness are presently ignored in the comparison.

first_node :

first librdf_node node

second_node :

second librdf_node node

Returns :

non 0 if nodes are equal. 0 if not-equal or failure

librdf_node_get_blank_identifier ()

unsigned char *     librdf_node_get_blank_identifier    (librdf_node *node);

Get the blank node identifier as a UTF-8 encoded string.

node :

the node object

Returns :

the UTF-8 encoded blank node identifier value or NULL on failure

librdf_node_get_counted_blank_identifier ()

unsigned char *     librdf_node_get_counted_blank_identifier
                                                        (librdf_node *node,
                                                         size_t *len_p);

Get the blank node identifier as a counted UTF-8 encoded string.

node :

the node object

len_p :

pointer to variable to store length (or NULL)

Returns :

the UTF-8 encoded blank node identifier value or NULL on failure

librdf_node_get_li_ordinal ()

int                 librdf_node_get_li_ordinal          (librdf_node *node);

Get the node li object ordinal value.

node :

the node object

Returns :

the li ordinal value or < 1 on failure

librdf_node_get_literal_value ()

unsigned char *     librdf_node_get_literal_value       (librdf_node *node);

Get the literal value of the node as a UTF-8 encoded string.

Returns a pointer to the UTF-8 encoded literal value held by the node, it must be copied if it is wanted to be used by the caller.

node :

the node object

Returns :

the UTF-8 encoded literal string or NULL if node is not a literal

librdf_node_get_literal_value_as_counted_string ()

unsigned char *     librdf_node_get_literal_value_as_counted_string
                                                        (librdf_node *node,
                                                         size_t *len_p);

Get the literal value of the node as a counted UTF-8 encoded string.

Returns a pointer to the UTF-8 encoded literal string value held by the node, it must be copied if it is wanted to be used by the caller.

node :

the node object

len_p :

pointer to location to store the string length (or NULL)

Returns :

the UTF-8 encoded literal string or NULL if node is not a literal

librdf_node_get_literal_value_as_latin1 ()

char *              librdf_node_get_literal_value_as_latin1
                                                        (librdf_node *node);

Get the string literal value of the node as ISO Latin-1.

Returns a newly allocated string containing the conversion of the node literal value held by the node into ISO Latin-1. Discards characters outside the U+0000 to U+00FF range (inclusive).

node :

the node object

Returns :

the Latin-1 literal string or NULL if node is not a literal

librdf_node_get_literal_value_datatype_uri ()

librdf_uri *        librdf_node_get_literal_value_datatype_uri
                                                        (librdf_node *node);

Get the typed literal datatype URI of the literal node.

node :

the node object

Returns :

shared URI of the datatyped literal or NULL if the node is not a literal, or has no datatype URI

librdf_node_get_literal_value_is_wf_xml ()

int                 librdf_node_get_literal_value_is_wf_xml
                                                        (librdf_node *node);

Get the XML well-formness property of the node.

node :

the node object

Returns :

0 if the XML literal is NOT well formed XML content, or the node is not a literal

librdf_node_get_literal_value_language ()

char *              librdf_node_get_literal_value_language
                                                        (librdf_node *node);

Get the XML language of the node.

Returns a pointer to the literal language value held by the node, it must be copied if it is wanted to be used by the caller. Language strings are ASCII, not UTF-8 encoded Unicode.

node :

the node object

Returns :

the XML language string or NULL if node is not a literal or there is no XML language defined.

librdf_node_get_type ()

librdf_node_type    librdf_node_get_type                (librdf_node *node);

Get the type of the node.

See also librdf_node_is_resource(), librdf_node_is_literal() and librdf_node_is_blank() for testing individual types.

node :

the node object

Returns :

the node type

librdf_node_get_uri ()

librdf_uri *        librdf_node_get_uri                 (librdf_node *node);

Get the URI for a node object.

Returns a pointer to the URI object held by the node, it must be copied if it is wanted to be used by the caller.

node :

the node object

Returns :

URI object or NULL if node has no URI.

librdf_node_is_blank ()

int                 librdf_node_is_blank                (librdf_node *node);

Check node is a blank nodeID.

node :

the node object

Returns :

non-zero if the node is a blank nodeID

librdf_node_is_literal ()

int                 librdf_node_is_literal              (librdf_node *node);

Check node is a literal.

node :

the node object

Returns :

non-zero if the node is a literal

librdf_node_is_resource ()

int                 librdf_node_is_resource             (librdf_node *node);

Check node is a resource.

node :

the node object

Returns :

non-zero if the node is a resource (URI)

librdf_node_new_static_node_iterator ()

librdf_iterator *   librdf_node_new_static_node_iterator
                                                        (librdf_world *world,
                                                         librdf_node **nodes,
                                                         int size);

Create an iterator over an array of nodes.

This creates an iterator for an existing static array of librdf_node objects. It is mostly intended for testing iterator code.

world :

world object

nodes :

static array of librdf_node objects

size :

size of array

Returns :

a librdf_iterator serialization of the nodes or NULL on failure

librdf_node_print ()

void                librdf_node_print                   (librdf_node *node,
                                                         FILE *fh);

Pretty print the node to a file descriptor.

This method is for debugging and the format of the output should not be relied on.

node :

the node

fh :

file handle

librdf_node_static_iterator_create ()

librdf_iterator *   librdf_node_static_iterator_create  (librdf_node **nodes,
                                                         int size);

Create an iterator over an array of nodes (ALWAYS FAILS)

This legacy method used to create an iterator for an existing static array of librdf_node objects. It was intended for testing iterator code.

deprecated: always returns NULL. Use librdf_node_new_static_node_iterator()

nodes :

static array of librdf_node objects

size :

size of array

Returns :

NULL

librdf_node_to_counted_string ()

unsigned char *     librdf_node_to_counted_string       (librdf_node *node,
                                                         size_t *len_p);

Format the node as a counted string in a debugging format.

Note a new string is allocated which must be freed by the caller.

Deprecated: Use librdf_node_write() to write to raptor_iostream which can be made to write to a string. Use a librdf_serializer to write proper syntax formats.

node :

the node object

len_p :

pointer to location to store length

Returns :

a string value representing the node or NULL on failure

librdf_node_to_string ()

unsigned char *     librdf_node_to_string               (librdf_node *node);

Format the node as a string in a debugging format.

Note a new string is allocated which must be freed by the caller.

Deprecated: Use librdf_node_write() to write to raptor_iostream which can be made to write to a string. Use a librdf_serializer to write proper syntax formats.

node :

the node object

Returns :

a string value representing the node or NULL on failure

enum librdf_node_type

typedef enum {
  LIBRDF_NODE_TYPE_UNKNOWN   = RAPTOR_TERM_TYPE_UNKNOWN,
  LIBRDF_NODE_TYPE_RESOURCE  = RAPTOR_TERM_TYPE_URI,
  LIBRDF_NODE_TYPE_LITERAL   = RAPTOR_TERM_TYPE_LITERAL,
  LIBRDF_NODE_TYPE_BLANK     = RAPTOR_TERM_TYPE_BLANK,
  LIBRDF_NODE_TYPE_LAST      = LIBRDF_NODE_TYPE_BLANK
} librdf_node_type;

Type of a redland node.

Better to check this with functions librdf_node_is_resource(), librdf_node_is_literal() or librdf_node_is_blank().

LIBRDF_NODE_TYPE_UNKNOWN

Internal

LIBRDF_NODE_TYPE_RESOURCE

rdf:Resource (& rdf:Property) - has a URI

LIBRDF_NODE_TYPE_LITERAL

rdf:Literal - has an XML string, language, XML space

LIBRDF_NODE_TYPE_BLANK

blank node has an identifier string.

LIBRDF_NODE_TYPE_LAST

Internal

librdf_node_write ()

int                 librdf_node_write                   (librdf_node *node,
                                                         raptor_iostream *iostr);

Write the node to an iostream in N-Triples format.

This method can be used to write a node in a relatively readable format. To write more compact formats use a serializer to pick a syntax and serialize triples to it.

node :

the node

iostr :

iostream to write to

Returns :

non-0 on failure


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