]> RDF Triple (librdf_statement) 3 REDLAND Library RDF Triple (librdf_statement) RDF Triple. typedef librdf_statement; enum librdf_statement_part; librdf_statement* librdf_new_statement (librdf_world *world); librdf_statement* librdf_new_statement_from_statement (librdf_statement *statement); librdf_statement* librdf_new_statement_from_nodes (librdf_world *world, librdf_node *subject, librdf_node *predicate, librdf_node *object); void librdf_statement_init (librdf_world *world, librdf_statement *statement); void librdf_statement_clear (librdf_statement *statement); void librdf_free_statement (librdf_statement *statement); librdf_node* librdf_statement_get_subject (librdf_statement *statement); void librdf_statement_set_subject (librdf_statement *statement, librdf_node *node); librdf_node* librdf_statement_get_predicate (librdf_statement *statement); void librdf_statement_set_predicate (librdf_statement *statement, librdf_node *node); librdf_node* librdf_statement_get_object (librdf_statement *statement); void librdf_statement_set_object (librdf_statement *statement, librdf_node *node); int librdf_statement_is_complete (librdf_statement *statement); unsigned char* librdf_statement_to_string (librdf_statement *statement); void librdf_statement_print (librdf_statement *statement, FILE *fh); int librdf_statement_equals (librdf_statement *statement1, librdf_statement *statement2); int librdf_statement_match (librdf_statement *statement, librdf_statement *partial_statement); size_t librdf_statement_encode (librdf_statement *statement, unsigned char *buffer, size_t length); size_t librdf_statement_encode_parts (librdf_statement *statement, librdf_node *context_node, unsigned char *buffer, size_t length, librdf_statement_part fields); size_t librdf_statement_decode (librdf_statement *statement, unsigned char *buffer, size_t length); size_t librdf_statement_decode_parts (librdf_statement *statement, librdf_node **context_node, unsigned char *buffer, size_t length); An object representing an RDF Triple of three RDF terms (librdf_node). Triples can be created, accessed, destroyed and en/decoded into a binary form for use in storage. librdf_statementtypedef struct librdf_statement_s librdf_statement; Redland statement class. librdf_statement_parttypedef 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_STATEMENT_SUBJECT Subject of a statement. LIBRDF_STATEMENT_PREDICATE Predicate of a statement. LIBRDF_STATEMENT_OBJECT Object of a statement. LIBRDF_STATEMENT_ALL All parts of a statement. librdf_new_statementlibrdf_statement* librdf_new_statement (librdf_world *world); Constructor - create a new empty librdf_statement. world : redland world object Returns : a new librdf_statement or NULL on failure librdf_new_statement_from_statementlibrdf_statement* librdf_new_statement_from_statement (librdf_statement *statement); Copy constructor - create a new librdf_statement from an existing librdf_statement. statement : librdf_statement to copy Returns : a new librdf_statement with copy or NULL on failure librdf_new_statement_from_nodeslibrdf_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). world : redland world object subject : librdf_node predicate : librdf_node object : librdf_node Returns : a new librdf_statement with copy or NULL on failure librdf_statement_initvoid 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). world : redland world object statement : librdf_statement object librdf_statement_clearvoid librdf_statement_clear (librdf_statement *statement); Empty a librdf_statement of nodes. statement : librdf_statement object librdf_free_statementvoid librdf_free_statement (librdf_statement *statement); Destructor - destroy a librdf_statement. statement : librdf_statement object librdf_statement_get_subjectlibrdf_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. statement : librdf_statement object Returns : a pointer to the librdf_node of the statement subject - librdf_statement_set_subjectvoid 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. statement : librdf_statement object node : librdf_node of subject librdf_statement_get_predicatelibrdf_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. statement : librdf_statement object Returns : a pointer to the librdf_node of the statement predicate - librdf_statement_set_predicatevoid 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. statement : librdf_statement object node : librdf_node of predicate librdf_statement_get_objectlibrdf_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. statement : librdf_statement object Returns : a pointer to the librdf_node of the statement object - librdf_statement_set_objectvoid 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. statement : librdf_statement object node : librdf_node of object librdf_statement_is_completeint 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. statement : librdf_statement object Returns : non 0 if the statement is complete and legal librdf_statement_to_stringunsigned 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. statement : the statement Returns : the string or NULL on failure. librdf_statement_printvoid 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. statement : the statement fh : file handle librdf_statement_equalsint librdf_statement_equals (librdf_statement *statement1, librdf_statement *statement2); Check if two statements are equal. statement1 : first librdf_statement statement2 : second librdf_statement Returns : non 0 if statements are equal librdf_statement_matchint 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() statement : statement partial_statement : statement with possible empty parts Returns : non 0 on match librdf_statement_encodesize_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. statement : the statement to serialise buffer : the buffer to use length : buffer size Returns : the number of bytes written or 0 on failure. librdf_statement_encode_partssize_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 statement : statement to serialise context_node : librdf_node context node (can be NULL) buffer : the buffer to use length : buffer size fields : fields to encode Returns : the number of bytes written or 0 on failure. librdf_statement_decodesize_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. statement : the statement to deserialise into buffer : the buffer to use length : buffer size Returns : number of bytes used or 0 on failure (bad encoding, allocation failure) librdf_statement_decode_partssize_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. statement : the statement to deserialise into context_node : pointer to librdf_node context_node to deserialise into buffer : the buffer to use length : buffer size Returns : number of bytes used or 0 on failure (bad encoding, allocation failure)