sord(3) Sord

Detailed Description

A lightweight RDF model library.

Sord stores RDF (subject object predicate context) quads, where the context may be omitted (to represent triples in the default graph).

Typedefs


typedef struct SordWorldImpl SordWorld

typedef struct SordModelImpl SordModel

typedef struct SordInserterImpl SordInserter

typedef struct SordIterImpl SordIter

typedef struct SordNodeImpl SordNode

typedef const SordNode * SordQuad[4]

Enumerations

World


SordWorld * sord_world_new (void)

void sord_world_free (SordWorld *world)

void sord_world_set_error_sink (SordWorld *world, SerdErrorSink error_sink, void *handle)

Node


SordNode * sord_new_uri (SordWorld *world, const uint8_t *uri)

SordNode * sord_new_relative_uri (SordWorld *world, const uint8_t *str, const uint8_t *base_uri)

SordNode * sord_new_blank (SordWorld *world, const uint8_t *str)

SordNode * sord_new_literal (SordWorld *world, SordNode *datatype, const uint8_t *str, const char *lang)

SordNode * sord_node_copy (const SordNode *node)

void sord_node_free (SordWorld *world, SordNode *node)

SordNodeType sord_node_get_type (const SordNode *node)

const uint8_t * sord_node_get_string (const SordNode *node)

const uint8_t * sord_node_get_string_counted (const SordNode *node, size_t *len)

const char * sord_node_get_language (const SordNode *node)

SordNode * sord_node_get_datatype (const SordNode *node)

SerdNodeFlags sord_node_get_flags (const SordNode *node)

bool sord_node_is_inline_object (const SordNode *node)

bool sord_node_equals (const SordNode *a, const SordNode *b)

const SerdNode * sord_node_to_serd_node (const SordNode *node)

SordNode * sord_node_from_serd_node (SordWorld *world, SerdEnv *env, const SerdNode *node, const SerdNode *datatype, const SerdNode *lang)

Model


SordModel * sord_new (SordWorld *world, unsigned indices, bool graphs)

void sord_free (SordModel *model)

SordWorld * sord_get_world (SordModel *model)

size_t sord_num_nodes (const SordWorld *world)

size_t sord_num_quads (const SordModel *model)

SordIter * sord_begin (const SordModel *model)

SordIter * sord_find (SordModel *model, const SordQuad pat)

SordIter * sord_search (SordModel *model, const SordNode *s, const SordNode *p, const SordNode *o, const SordNode *g)

SordNode * sord_get (SordModel *model, const SordNode *s, const SordNode *p, const SordNode *o, const SordNode *g)

bool sord_ask (SordModel *model, const SordNode *s, const SordNode *p, const SordNode *o, const SordNode *g)

uint64_t sord_count (SordModel *model, const SordNode *s, const SordNode *p, const SordNode *o, const SordNode *g)

bool sord_contains (SordModel *model, const SordQuad pat)

bool sord_add (SordModel *model, const SordQuad quad)

void sord_remove (SordModel *model, const SordQuad quad)

SerdStatus sord_erase (SordModel *model, SordIter *iter)

Inserter


SordInserter * sord_inserter_new (SordModel *model, SerdEnv *env)

void sord_inserter_free (SordInserter *inserter)

SerdStatus sord_inserter_set_base_uri (SordInserter *inserter, const SerdNode *uri)

SerdStatus sord_inserter_set_prefix (SordInserter *inserter, const SerdNode *name, const SerdNode *uri)

SerdStatus sord_inserter_write_statement (SordInserter *inserter, SerdStatementFlags flags, const SerdNode *graph, const SerdNode *subject, const SerdNode *predicate, const SerdNode *object, const SerdNode *object_datatype, const SerdNode *object_lang)

Iteration


void sord_iter_get (const SordIter *iter, SordQuad quad)

const SordNode * sord_iter_get_node (const SordIter *iter, SordQuadIndex index)

const SordModel * sord_iter_get_model (SordIter *iter)

bool sord_iter_next (SordIter *iter)

bool sord_iter_end (const SordIter *iter)

void sord_iter_free (SordIter *iter)

Utilities


bool sord_quad_match (const SordQuad x, const SordQuad y)

Serialisation


SerdReader * sord_new_reader (SordModel *model, SerdEnv *env, SerdSyntax syntax, SordNode *graph)

bool sord_write (SordModel *model, SerdWriter *writer, SordNode *graph)

bool sord_write_iter (SordIter *iter, SerdWriter *writer)

Typedef Documentation

typedef struct SordWorldImpl SordWorld

Sord World. The World represents all library state, including interned strings.

typedef struct SordModelImpl SordModel

Sord Model. A model is an indexed set of Quads (i.e. it can contain several RDF graphs). It may be searched using various patterns depending on which indices are enabled.

typedef struct SordInserterImpl SordInserter

Model Inserter. An inserter is used for writing statements to a model using the Serd sink interface. This makes it simple to write to a model directly using a SerdReader, or any other code that writes statements to a SerdStatementSink.

typedef struct SordIterImpl SordIter

Model Iterator.

typedef struct SordNodeImpl SordNode

RDF Node. A Node is a component of a Quad. Nodes may be URIs, blank nodes, or (in the case of quad objects only) string literals. Literal nodes may have an associate language or datatype (but not both).

typedef const SordNode* SordQuad[4]

Quad of nodes (a statement), or a quad pattern. Nodes are ordered (S P O G). The ID of the default graph is 0.

Enumeration Type Documentation

enum SordQuadIndex

Index into a SordQuad.

Enumerator

SORD_SUBJECT
Subject.
SORD_PREDICATE
Predicate (a.k.a. 'key')
SORD_OBJECT
Object (a.k.a. 'value')
SORD_GRAPH
Graph (a.k.a. 'context')

enum SordNodeType

Type of a node.

Enumerator

SORD_URI
URI.
SORD_BLANK
Blank node identifier.
SORD_LITERAL
Literal (string with optional lang or datatype)

enum SordIndexOption

Indexing option.

Enumerator

SORD_SPO
Subject, Predicate, Object.
SORD_SOP
Subject, Object, Predicate.
SORD_OPS
Object, Predicate, Subject.
SORD_OSP
Object, Subject, Predicate.
SORD_PSO
Predicate, Subject, Object.
SORD_POS
Predicate, Object, Subject.

Function Documentation

SordWorld* sord_world_new (void)

Create a new Sord World. It is safe to use multiple worlds in one process, though no data (e.g. nodes) can be shared between worlds, and this should be avoided if possible for performance reasons.

void sord_world_free (SordWorld * world)

Free world.

void sord_world_set_error_sink (SordWorld * world, SerdErrorSink error_sink, void * handle)

Set a function to be called when errors occur. The error_sink will be called with handle as its first argument. If no error function is set, errors are printed to stderr.

SordNode* sord_new_uri (SordWorld * world, const uint8_t * uri)

Get a URI node from a string. Note this function measures str, which is a common bottleneck. Use sord_node_from_serd_node instead if str is already measured.

SordNode* sord_new_relative_uri (SordWorld * world, const uint8_t * str, const uint8_t * base_uri)

Get a URI node from a relative URI string.

SordNode* sord_new_blank (SordWorld * world, const uint8_t * str)

Get a blank node from a string. Note this function measures str, which is a common bottleneck. Use sord_node_from_serd_node instead if str is already measured.

SordNode* sord_new_literal (SordWorld * world, SordNode * datatype, const uint8_t * str, const char * lang)

Get a literal node from a string. Note this function measures str, which is a common bottleneck. Use sord_node_from_serd_node instead if str is already measured.

SordNode* sord_node_copy (const SordNode * node)

Copy a node (obtain a reference). Node that since nodes are interned and reference counted, this does not actually create a deep copy of node.

void sord_node_free (SordWorld * world, SordNode * node)

Free a node (drop a reference).

SordNodeType sord_node_get_type (const SordNode * node)

Return the type of a node (SORD_URI, SORD_BLANK, or SORD_LITERAL).

const uint8_t* sord_node_get_string (const SordNode * node)

Return the string value of a node.

const uint8_t* sord_node_get_string_counted (const SordNode * node, size_t * len)

Return the string value of a node, and set len to its length.

const char* sord_node_get_language (const SordNode * node)

Return the language of a literal node (or NULL).

SordNode* sord_node_get_datatype (const SordNode * node)

Return the datatype URI of a literal node (or NULL).

SerdNodeFlags sord_node_get_flags (const SordNode * node)

Return the flags (string attributes) of a node.

bool sord_node_is_inline_object (const SordNode * node)

Return true iff node can be serialised as an inline object. More specifically, this returns true iff the node is the object field of exactly one statement, and therefore can be inlined since it needn't be referred to by name.

bool sord_node_equals (const SordNode * a, const SordNode * b)

Return true iff a is equal to b. Note this is much faster than comparing the node's strings.

const SerdNode* sord_node_to_serd_node (const SordNode * node)

Return a SordNode as a SerdNode. The returned node is shared and must not be freed or modified.

SordNode* sord_node_from_serd_node (SordWorld * world, SerdEnv * env, const SerdNode * node, const SerdNode * datatype, const SerdNode * lang)

Create a new SordNode from a SerdNode. The returned node must be freed using sord_node_free.

SordModel* sord_new (SordWorld * world, unsigned indices, bool graphs)

Create a new model.

Parameters:

world The world in which to make this model.
indices SordIndexOption flags (e.g. SORD_SPO|SORD_OPS). Be sure to enable an index where the most significant node(s) are not variables in your queries (e.g. to make (? P O) queries, enable either SORD_OPS or SORD_POS).
graphs If true, store (and index) graph contexts.

void sord_free (SordModel * model)

Close and free model.

SordWorld* sord_get_world (SordModel * model)

Get the world associated with model.

size_t sord_num_nodes (const SordWorld * world)

Return the number of nodes stored in world. Nodes are included in this count iff they are a part of a quad in world.

size_t sord_num_quads (const SordModel * model)

Return the number of quads stored in model.

SordIter* sord_begin (const SordModel * model)

Return an iterator to the start of model.

SordIter* sord_find (SordModel * model, const SordQuad pat)

Search for statements by a quad pattern.

Returns:

an iterator to the first match, or NULL if no matches found.

SordIter* sord_search (SordModel * model, const SordNode * s, const SordNode * p, const SordNode * o, const SordNode * g)

Search for statements by nodes.

Returns:

an iterator to the first match, or NULL if no matches found.

SordNode* sord_get (SordModel * model, const SordNode * s, const SordNode * p, const SordNode * o, const SordNode * g)

Search for a single node that matches a pattern. Exactly one of s, p, o must be NULL. This function is mainly useful for predicates that only have one value. The returned node must be freed using sord_node_free.

Returns:

the first matching node, or NULL if no matches are found.

bool sord_ask (SordModel * model, const SordNode * s, const SordNode * p, const SordNode * o, const SordNode * g)

Return true iff a statement exists.

uint64_t sord_count (SordModel * model, const SordNode * s, const SordNode * p, const SordNode * o, const SordNode * g)

Return the number of matching statements.

bool sord_contains (SordModel * model, const SordQuad pat)

Check if model contains a triple pattern.

Returns:

true if model contains a match for pat, otherwise false.

bool sord_add (SordModel * model, const SordQuad quad)

Add a quad to a model. Calling this function invalidates all iterators on model.

Returns:

true on success, false, on error.

void sord_remove (SordModel * model, const SordQuad quad)

Remove a quad from a model. Calling this function invalidates all iterators on model. To remove quads while iterating, use sord_erase() instead.

SerdStatus sord_erase (SordModel * model, SordIter * iter)

Remove a quad from a model via an iterator. Calling this function invalidates all iterators on model except iter.

Parameters:

iter Iterator to the element to erase, which is incremented to the next value on return.

SordInserter* sord_inserter_new (SordModel * model, SerdEnv * env)

Create an inserter for writing statements to a model.

void sord_inserter_free (SordInserter * inserter)

Free an inserter.

SerdStatus sord_inserter_set_base_uri (SordInserter * inserter, const SerdNode * uri)

Set the current base URI for writing to the model. Note this function can be safely casted to SerdBaseSink.

SerdStatus sord_inserter_set_prefix (SordInserter * inserter, const SerdNode * name, const SerdNode * uri)

Set a namespace prefix for writing to the model. Note this function can be safely casted to SerdPrefixSink.

SerdStatus sord_inserter_write_statement (SordInserter * inserter, SerdStatementFlags flags, const SerdNode * graph, const SerdNode * subject, const SerdNode * predicate, const SerdNode * object, const SerdNode * object_datatype, const SerdNode * object_lang)

Write a statement to the model. Note this function can be safely casted to SerdStatementSink.

void sord_iter_get (const SordIter * iter, SordQuad quad)

Set quad to the quad pointed to by iter.

const SordNode* sord_iter_get_node (const SordIter * iter, SordQuadIndex index)

Return a field of the quad pointed to by iter.

const SordModel* sord_iter_get_model (SordIter * iter)

Return the store pointed to by iter.

bool sord_iter_next (SordIter * iter)

Increment iter to point to the next statement.

bool sord_iter_end (const SordIter * iter)

Return true iff iter is at the end of its range.

void sord_iter_free (SordIter * iter)

Free iter.

bool sord_quad_match (const SordQuad x, const SordQuad y)

Match two quads (using ID comparison only). This function is a straightforward and fast equivalence match with wildcard support (ID 0 is a wildcard). It does not actually read node data.

Returns:

true iff x and y match.

SerdReader* sord_new_reader (SordModel * model, SerdEnv * env, SerdSyntax syntax, SordNode * graph)

Return a reader that will read into model.

bool sord_write (SordModel * model, SerdWriter * writer, SordNode * graph)

Write a model to a writer.

bool sord_write_iter (SordIter * iter, SerdWriter * writer)

Write a range to a writer. This increments iter to its end, then frees it.

Author

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