librdf_statement

typedef struct librdf_statement_s librdf_statement;

Redland statement class.

enum librdf_statement_part

typedef enum {
  LIBRDF_STATEMENT_SUBJECT   = 1 << 0,
  LIBRDF_STATEMENT_PREDICATE = 1 << 1,
  LIBRDF_STATEMENT_OBJECT    = 1 << 2,

  /* must be a combination of all of the above */
  LIBRDF_STATEMENT_ALL       = (LIBRDF_STATEMENT_SUBJECT|
                                LIBRDF_STATEMENT_PREDICATE|
                                LIBRDF_STATEMENT_OBJECT)
} librdf_statement_part;

Flags that are or-ed to indicate statement parts.

Used in fields arguments to methods such as the public librdf_statement_encode_parts() librdf_statement_decode_parts() librdf_new_stream_from_node_iterator() and the internal librdf_storage_node_stream_to_node_create()

librdf_new_statement ()

librdf_statement*   librdf_new_statement                (librdf_world *world);

Constructor - create a new empty librdf_statement.

librdf_new_statement_from_statement ()

librdf_statement*   librdf_new_statement_from_statement (librdf_statement *statement);

Copy constructor - create a new librdf_statement from an existing librdf_statement.

librdf_new_statement_from_nodes ()

librdf_statement*   librdf_new_statement_from_nodes     (librdf_world *world,
                                                         librdf_node *subject,
                                                         librdf_node *predicate,
                                                         librdf_node *object);

Constructor - create a new librdf_statement from existing librdf_node objects.

The node objects become owned by the new statement (or freed on error).

librdf_statement_init ()

void                librdf_statement_init               (librdf_world *world,
                                                         librdf_statement *statement);

Initialise a statically declared librdf_statement.

This MUST be called on a statically declared librdf_statement to initialise it properly. It is the responsibility of the user of the statically allocated librdf_statement to deal with deallocation of any statement parts (subject, predicate, object).

librdf_statement_clear ()

void                librdf_statement_clear              (librdf_statement *statement);

Empty a librdf_statement of nodes.

librdf_free_statement ()

void                librdf_free_statement               (librdf_statement *statement);

Destructor - destroy a librdf_statement.

librdf_statement_get_subject ()

librdf_node*        librdf_statement_get_subject        (librdf_statement *statement);

Get the statement subject.

This method returns a SHARED pointer to the subject which must be copied by the caller if needed.

librdf_statement_set_subject ()

void                librdf_statement_set_subject        (librdf_statement *statement,
                                                         librdf_node *node);

Set the statement subject.

The subject passed in becomes owned by the statement object and must not be used by the caller after this call.

librdf_statement_get_predicate ()

librdf_node*        librdf_statement_get_predicate      (librdf_statement *statement);

Get the statement predicate.

This method returns a SHARED pointer to the predicate which must be copied by the caller if needed.

librdf_statement_set_predicate ()

void                librdf_statement_set_predicate      (librdf_statement *statement,
                                                         librdf_node *node);

Set the statement predicate.

The predicate passed in becomes owned by the statement object and must not be used by the caller after this call.

librdf_statement_get_object ()

librdf_node*        librdf_statement_get_object         (librdf_statement *statement);

Get the statement object.

This method returns a SHARED pointer to the object which must be copied by the caller if needed.

librdf_statement_set_object ()

void                librdf_statement_set_object         (librdf_statement *statement,
                                                         librdf_node *node);

Set the statement object.

The object passed in becomes owned by the statement object and must not be used by the caller after this call.

librdf_statement_is_complete ()

int                 librdf_statement_is_complete        (librdf_statement *statement);

Check if statement is a complete and legal RDF triple.

Checks that all subject, predicate, object fields are present and they have the allowed node types.

librdf_statement_to_string ()

unsigned char*      librdf_statement_to_string          (librdf_statement *statement);

Format the librdf_statement as a string.

Formats the statement as a newly allocate string that must be freed by the caller.

librdf_statement_print ()

void                librdf_statement_print              (librdf_statement *statement,
                                                         FILE *fh);

Pretty print the statement to a file descriptor.

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

librdf_statement_equals ()

int                 librdf_statement_equals             (librdf_statement *statement1,
                                                         librdf_statement *statement2);

Check if two statements are equal.

librdf_statement_match ()

int                 librdf_statement_match              (librdf_statement *statement,
                                                         librdf_statement *partial_statement);

Match a statement against a 'partial' statement.

A partial statement is where some parts of the statement - subject, predicate or object can be empty (NULL). Empty parts match against any value, parts with values must match exactly. Node matching is done via librdf_node_equals()

librdf_statement_encode ()

size_t              librdf_statement_encode             (librdf_statement *statement,
                                                         unsigned char *buffer,
                                                         size_t length);

Serialise a statement into a buffer.

Encodes the given statement 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.

librdf_statement_encode_parts ()

size_t              librdf_statement_encode_parts       (librdf_statement *statement,
                                                         librdf_node *context_node,
                                                         unsigned char *buffer,
                                                         size_t length,
                                                         librdf_statement_part fields);

Serialise parts of a statement into a buffer.

Encodes the given statement 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.

The fields values are or-ed combinations of: LIBRDF_STATEMENT_SUBJECT LIBRDF_STATEMENT_PREDICATE LIBRDF_STATEMENT_OBJECT or LIBRDF_STATEMENT_ALL for subject,prdicate,object fields

If context_node is given, it is encoded also

librdf_statement_decode ()

size_t              librdf_statement_decode             (librdf_statement *statement,
                                                         unsigned char *buffer,
                                                         size_t length);

Decodes a statement from a buffer.

Decodes the serialised statement (as created by librdf_statement_encode() ) from the given buffer.

librdf_statement_decode_parts ()

size_t              librdf_statement_decode_parts       (librdf_statement *statement,
                                                         librdf_node **context_node,
                                                         unsigned char *buffer,
                                                         size_t length);

Decodes a statement + context node from a buffer.

Decodes the serialised statement (as created by librdf_statement_encode() ) from the given buffer. If a context node is found and context_node is not NULL, a pointer to the new librdf_node is stored in *context_node.