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
enum	SordQuadIndex {   SORD_SUBJECT = 0 ,   SORD_PREDICATE = 1 ,   SORD_OBJECT = 2 ,   SORD_GRAPH = 3 }
enum	SordNodeType {   SORD_URI = 1 ,   SORD_BLANK = 2 ,   SORD_LITERAL = 3 }
enum	SordIndexOption {   SORD_SPO = 1 ,   SORD_SOP = 1 << 1 ,   SORD_OPS = 1 << 2 ,   SORD_OSP = 1 << 3 ,   SORD_PSO = 1 << 4 ,   SORD_POS = 1 << 5 }

World
SORD_API SordWorld *	sord_world_new (void)
SORD_API void	sord_world_free (SordWorld *world)
SORD_API void	sord_world_set_error_sink (SordWorld *world, SerdErrorSink error_sink, void *handle)

Node
SORD_API SordNode *	sord_new_uri (SordWorld *world, const uint8_t *uri)
SORD_API SordNode *	sord_new_relative_uri (SordWorld *world, const uint8_t *uri, const uint8_t *base_uri)
SORD_API SordNode *	sord_new_blank (SordWorld *world, const uint8_t *str)
SORD_API SordNode *	sord_new_literal (SordWorld *world, SordNode *datatype, const uint8_t *str, const char *lang)
SORD_API SordNode *	sord_node_copy (const SordNode *node)
SORD_API void	sord_node_free (SordWorld *world, SordNode *node)
SORD_API SordNodeType	sord_node_get_type (const SordNode *node)
SORD_API const uint8_t *	sord_node_get_string (const SordNode *node)
SORD_API const uint8_t *	sord_node_get_string_counted (const SordNode *node, size_t *bytes)
SORD_API const uint8_t *	sord_node_get_string_measured (const SordNode *node, size_t *bytes, size_t *chars)
SORD_API const char *	sord_node_get_language (const SordNode *node)
SORD_API SordNode *	sord_node_get_datatype (const SordNode *node)
SORD_API SerdNodeFlags	sord_node_get_flags (const SordNode *node)
SORD_API bool	sord_node_is_inline_object (const SordNode *node)
SORD_API bool	sord_node_equals (const SordNode *a, const SordNode *b)
SORD_API const SerdNode *	sord_node_to_serd_node (const SordNode *node)
SORD_API SordNode *	sord_node_from_serd_node (SordWorld *world, SerdEnv *env, const SerdNode *node, const SerdNode *datatype, const SerdNode *lang)

Model
SORD_API SordModel *	sord_new (SordWorld *world, unsigned indices, bool graphs)
SORD_API void	sord_free (SordModel *model)
SORD_API SordWorld *	sord_get_world (SordModel *model)
SORD_API size_t	sord_num_nodes (const SordWorld *world)
SORD_API size_t	sord_num_quads (const SordModel *model)
SORD_API SordIter *	sord_begin (const SordModel *model)
SORD_API SordIter *	sord_find (SordModel *model, const SordQuad pat)
SORD_API SordIter *	sord_search (SordModel *model, const SordNode *s, const SordNode *p, const SordNode *o, const SordNode *g)
SORD_API SordNode *	sord_get (SordModel *model, const SordNode *s, const SordNode *p, const SordNode *o, const SordNode *g)
SORD_API bool	sord_ask (SordModel *model, const SordNode *s, const SordNode *p, const SordNode *o, const SordNode *g)
SORD_API uint64_t	sord_count (SordModel *model, const SordNode *s, const SordNode *p, const SordNode *o, const SordNode *g)
SORD_API bool	sord_contains (SordModel *model, const SordQuad pat)
SORD_API bool	sord_add (SordModel *model, const SordQuad tup)
SORD_API void	sord_remove (SordModel *model, const SordQuad tup)
SORD_API SerdStatus	sord_erase (SordModel *model, SordIter *iter)

Inserter
SORD_API SordInserter *	sord_inserter_new (SordModel *model, SerdEnv *env)
SORD_API void	sord_inserter_free (SordInserter *inserter)
SORD_API SerdStatus	sord_inserter_set_base_uri (SordInserter *inserter, const SerdNode *uri)
SORD_API SerdStatus	sord_inserter_set_prefix (SordInserter *inserter, const SerdNode *name, const SerdNode *uri)
SORD_API 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
SORD_API void	sord_iter_get (const SordIter *iter, SordQuad tup)
SORD_API const SordNode *	sord_iter_get_node (const SordIter *iter, SordQuadIndex index)
SORD_API const SordModel *	sord_iter_get_model (SordIter *iter)
SORD_API bool	sord_iter_next (SordIter *iter)
SORD_API bool	sord_iter_end (const SordIter *iter)
SORD_API void	sord_iter_free (SordIter *iter)

Utilities
SORD_API bool	sord_quad_match (const SordQuad x, const SordQuad y)

Serialisation
SORD_API SerdReader *	sord_new_reader (SordModel *model, SerdEnv *env, SerdSyntax syntax, SordNode *graph)
SORD_API bool	sord_write (SordModel *model, SerdWriter *writer, SordNode *graph)
SORD_API bool	sord_write_iter (SordIter *iter, SerdWriter *writer)

Typedef Documentation

SordWorld

typedef struct SordWorldImpl SordWorld

Sord World.

The World represents all library state, including interned strings.

SordModel

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.

SordInserter

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.

SordIter

typedef struct SordIterImpl SordIter

Model Iterator.

SordNode

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).

SordQuad

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

SordQuadIndex

enum SordQuadIndex

Index into a SordQuad.

Enumerator
SORD_SUBJECT	Subject.
SORD_PREDICATE	Predicate ("key")
SORD_OBJECT	Object ("value")
SORD_GRAPH	Graph ("context")

SordNodeType

enum SordNodeType

Type of a node.

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

SordIndexOption

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

sord_world_new()

SORD_API 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.

sord_world_free()

SORD_API void sord_world_free

(

SordWorld *

world

)

Free world.

sord_world_set_error_sink()

SORD_API 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.

sord_new_uri()

SORD_API 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.

sord_new_relative_uri()

SORD_API SordNode * sord_new_relative_uri	(	SordWorld *	world,
		const uint8_t *	uri,
		const uint8_t *	base_uri
	)

Get a URI node from a relative URI string.

sord_new_blank()

SORD_API 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.

sord_new_literal()

SORD_API 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.

sord_node_copy()

SORD_API 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.

sord_node_free()

SORD_API void sord_node_free	(	SordWorld *	world,
		SordNode *	node
	)

Free a node (drop a reference).

sord_node_get_type()

SORD_API SordNodeType sord_node_get_type

(

const SordNode *

node

)

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

sord_node_get_string()

SORD_API const uint8_t * sord_node_get_string

(

const SordNode *

node

)

Return the string value of a node.

sord_node_get_string_counted()

SORD_API const uint8_t * sord_node_get_string_counted	(	const SordNode *	node,
		size_t *	bytes
	)

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

sord_node_get_string_measured()

SORD_API const uint8_t * sord_node_get_string_measured	(	const SordNode *	node,
		size_t *	bytes,
		size_t *	chars
	)

Return the string value of a node, and set bytes to its length in bytes, and count to its length in characters.

sord_node_get_language()

SORD_API const char * sord_node_get_language

(

const SordNode *

node

)

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

sord_node_get_datatype()

SORD_API SordNode * sord_node_get_datatype

(

const SordNode *

node

)

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

sord_node_get_flags()

SORD_API SerdNodeFlags sord_node_get_flags

(

const SordNode *

node

)

Return the flags (string attributes) of a node.

sord_node_is_inline_object()

SORD_API 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.

sord_node_equals()

SORD_API 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.

sord_node_to_serd_node()

SORD_API 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.

sord_node_from_serd_node()

SORD_API 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().

sord_new()

SORD_API 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.

sord_free()

SORD_API void sord_free

(

SordModel *

model

)

Close and free model.

sord_get_world()

SORD_API SordWorld * sord_get_world

(

SordModel *

model

)

Get the world associated with model.

sord_num_nodes()

SORD_API 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.

sord_num_quads()

SORD_API size_t sord_num_quads

(

const SordModel *

model

)

Return the number of quads stored in model.

sord_begin()

SORD_API SordIter * sord_begin

(

const SordModel *

model

)

Return an iterator to the start of model.

sord_find()

SORD_API 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.

sord_search()

SORD_API 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.

sord_get()

SORD_API 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.

sord_ask()

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

Return true iff a statement exists.

sord_count()

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

Return the number of matching statements.

sord_contains()

SORD_API 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.

sord_add()

SORD_API bool sord_add	(	SordModel *	model,
		const SordQuad	tup
	)

Add a quad to a model.

Calling this function invalidates all iterators on model.

Returns

true on success, false, on error.

sord_remove()

SORD_API void sord_remove	(	SordModel *	model,
		const SordQuad	tup
	)

Remove a quad from a model.

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

sord_erase()

SORD_API 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

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

sord_inserter_new()

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

Create an inserter for writing statements to a model.

sord_inserter_free()

SORD_API void sord_inserter_free

(

SordInserter *

inserter

)

Free an inserter.

sord_inserter_set_base_uri()

SORD_API 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.

sord_inserter_set_prefix()

SORD_API 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.

sord_inserter_write_statement()

SORD_API 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.

sord_iter_get()

SORD_API void sord_iter_get	(	const SordIter *	iter,
		SordQuad	tup
	)

Set quad to the quad pointed to by iter.

sord_iter_get_node()

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

Return a field of the quad pointed to by iter.

Returns NULL if iter is NULL or is at the end.

sord_iter_get_model()

SORD_API const SordModel * sord_iter_get_model

(

SordIter *

iter

)

Return the store pointed to by iter.

sord_iter_next()

SORD_API bool sord_iter_next

(

SordIter *

iter

)

Increment iter to point to the next statement.

sord_iter_end()

SORD_API bool sord_iter_end

(

const SordIter *

iter

)

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

sord_iter_free()

SORD_API void sord_iter_free

(

SordIter *

iter

)

Free iter.

sord_quad_match()

SORD_API 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.

sord_new_reader()

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

Return a reader that will read into model.

sord_write()

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

Write a model to a writer.

sord_write_iter()

SORD_API bool sord_write_iter	(	SordIter *	iter,
		SerdWriter *	writer
	)

Write a range to a writer.

This increments iter to its end, then frees it.