Helper functions for the LV2 Atom extension. More...

Data Structures
struct	LV2_Atom_Object_Query
	A single entry in an Object query. More...
Functions
static uint32_t	lv2_atom_pad_size (uint32_t size)
	Pad a size to 64 bits.
static uint32_t	lv2_atom_total_size (const LV2_Atom *atom)
	Return the total size of `atom`, including the header.
static bool	lv2_atom_is_null (const LV2_Atom *atom)
	Return true iff `atom` is null.
static bool	lv2_atom_equals (const LV2_Atom a, const LV2_Atom b)
	Return true iff `a` is equal to `b`.
Sequence Utilities
static void	lv2_atom_sequence_clear (LV2_Atom_Sequence *seq)
	Clear all events from `sequence`.
static LV2_Atom_Event *	lv2_atom_sequence_append_event (LV2_Atom_Sequence seq, uint32_t capacity, const LV2_Atom_Event event)
	Append an event at the end of `sequence`.
Sequence Iterator
#define	LV2_ATOM_SEQUENCE_FOREACH(seq, iter)
	A macro for iterating over all events in a Sequence.
#define	LV2_ATOM_SEQUENCE_BODY_FOREACH(body, size, iter)
	Like LV2_ATOM_SEQUENCE_FOREACH but for a headerless sequence body.
static LV2_Atom_Event *	lv2_atom_sequence_begin (const LV2_Atom_Sequence_Body *body)
	Get an iterator pointing to the first event in a Sequence body.
static LV2_Atom_Event *	lv2_atom_sequence_end (const LV2_Atom_Sequence_Body *body, uint32_t size)
	Get an iterator pointing to the end of a Sequence body.
static bool	lv2_atom_sequence_is_end (const LV2_Atom_Sequence_Body body, uint32_t size, const LV2_Atom_Event i)
	Return true iff `i` has reached the end of `body`.
static LV2_Atom_Event *	lv2_atom_sequence_next (const LV2_Atom_Event *i)
	Return an iterator to the element following `i`.
Tuple Iterator
#define	LV2_ATOM_TUPLE_FOREACH(tuple, iter)
	A macro for iterating over all properties of a Tuple.
#define	LV2_ATOM_TUPLE_BODY_FOREACH(body, size, iter)
	Like LV2_ATOM_TUPLE_FOREACH but for a headerless tuple body.
static LV2_Atom *	lv2_atom_tuple_begin (const LV2_Atom_Tuple *tup)
	Get an iterator pointing to the first element in `tup`.
static bool	lv2_atom_tuple_is_end (const void body, uint32_t size, const LV2_Atom i)
	Return true iff `i` has reached the end of `body`.
static LV2_Atom *	lv2_atom_tuple_next (const LV2_Atom *i)
	Return an iterator to the element following `i`.
Object Iterator
#define	LV2_ATOM_OBJECT_FOREACH(obj, iter)
	A macro for iterating over all properties of an Object.
#define	LV2_ATOM_OBJECT_BODY_FOREACH(body, size, iter)
	Like LV2_ATOM_OBJECT_FOREACH but for a headerless object body.
static LV2_Atom_Property_Body *	lv2_atom_object_begin (const LV2_Atom_Object_Body *body)
	Return a pointer to the first property in `body`.
static bool	lv2_atom_object_is_end (const LV2_Atom_Object_Body body, uint32_t size, const LV2_Atom_Property_Body i)
	Return true iff `i` has reached the end of `obj`.
static LV2_Atom_Property_Body *	lv2_atom_object_next (const LV2_Atom_Property_Body *i)
	Return an iterator to the property following `i`.
Object Query
static const LV2_Atom_Object_Query	LV2_ATOM_OBJECT_QUERY_END = { 0, NULL }
static int	lv2_atom_object_query (const LV2_Atom_Object object, LV2_Atom_Object_Query query)
	Get an object's values for various keys.
static int	lv2_atom_object_body_get (uint32_t size, const LV2_Atom_Object_Body *body,...)
	Body only version of lv2_atom_object_get().
static int	lv2_atom_object_get (const LV2_Atom_Object *object,...)
	Variable argument version of lv2_atom_object_query().

Detailed Description

Helper functions for the LV2 Atom extension.

Note these functions are all static inline, do not take their address.

This header is non-normative, it is provided for convenience.

Define Documentation

#define LV2_ATOM_SEQUENCE_FOREACH	(	seq,
		iter
	)

Value:

for (LV2_Atom_Event* (iter) = lv2_atom_sequence_begin(&(seq)->body); \
         !lv2_atom_sequence_is_end(&(seq)->body, (seq)->atom.size, (iter)); \
         (iter) = lv2_atom_sequence_next(iter))

A macro for iterating over all events in a Sequence.

Parameters:

seq	The sequence to iterate over
iter	The name of the iterator

This macro is used similarly to a for loop (which it expands to), e.g.:

   LV2_ATOM_SEQUENCE_FOREACH(sequence, ev) {
       // Do something with ev (an LV2_Atom_Event*) here...
   }

#define LV2_ATOM_SEQUENCE_BODY_FOREACH	(	body,
		size,
		iter
	)

Value:

for (LV2_Atom_Event* (iter) = lv2_atom_sequence_begin(body); \
         !lv2_atom_sequence_is_end(body, size, (iter)); \
         (iter) = lv2_atom_sequence_next(iter))

Like LV2_ATOM_SEQUENCE_FOREACH but for a headerless sequence body.

#define LV2_ATOM_TUPLE_FOREACH	(	tuple,
		iter
	)

Value:

for (LV2_Atom* (iter) = lv2_atom_tuple_begin(tuple); \
         !lv2_atom_tuple_is_end(LV2_ATOM_BODY(tuple), (tuple)->size, (iter)); \
         (iter) = lv2_atom_tuple_next(iter))

A macro for iterating over all properties of a Tuple.

Parameters:

tuple	The tuple to iterate over
iter	The name of the iterator

This macro is used similarly to a for loop (which it expands to), e.g.:

   LV2_ATOMO_TUPLE_FOREACH(tuple, elem) {
       // Do something with elem (an LV2_Atom*) here...
   }

#define LV2_ATOM_TUPLE_BODY_FOREACH	(	body,
		size,
		iter
	)

Value:

for (LV2_Atom* (iter) = (LV2_Atom*)body; \
         !lv2_atom_tuple_is_end(body, size, (iter)); \
         (iter) = lv2_atom_tuple_next(iter))

Like LV2_ATOM_TUPLE_FOREACH but for a headerless tuple body.

#define LV2_ATOM_OBJECT_FOREACH	(	obj,
		iter
	)

Value:

for (LV2_Atom_Property_Body* (iter) = lv2_atom_object_begin(&(obj)->body); \
         !lv2_atom_object_is_end(&(obj)->body, (obj)->atom.size, (iter)); \
         (iter) = lv2_atom_object_next(iter))

A macro for iterating over all properties of an Object.

Parameters:

obj	The object to iterate over
iter	The name of the iterator

This macro is used similarly to a for loop (which it expands to), e.g.:

   LV2_ATOM_OBJECT_FOREACH(object, i) {
       // Do something with prop (an LV2_Atom_Property_Body*) here...
   }

#define LV2_ATOM_OBJECT_BODY_FOREACH	(	body,
		size,
		iter
	)

Value:

for (LV2_Atom_Property_Body* (iter) = lv2_atom_object_begin(body); \
         !lv2_atom_object_is_end(body, size, (iter)); \
         (iter) = lv2_atom_object_next(iter))

Like LV2_ATOM_OBJECT_FOREACH but for a headerless object body.

Function Documentation

static uint32_t lv2_atom_pad_size ( uint32_t size ) [inline, static]

Pad a size to 64 bits.

static uint32_t lv2_atom_total_size ( const LV2_Atom * atom ) [inline, static]

Return the total size of `atom`, including the header.

static bool lv2_atom_is_null ( const LV2_Atom * atom ) [inline, static]

Return true iff `atom` is null.

static bool lv2_atom_equals	(	const LV2_Atom *	a,
		const LV2_Atom *	b
	)		`[inline, static]`

Return true iff `a` is equal to `b`.

static LV2_Atom_Event* lv2_atom_sequence_begin ( const LV2_Atom_Sequence_Body * body ) [inline, static]

Get an iterator pointing to the first event in a Sequence body.

static LV2_Atom_Event* lv2_atom_sequence_end	(	const LV2_Atom_Sequence_Body *	body,
		uint32_t	size
	)		`[inline, static]`

Get an iterator pointing to the end of a Sequence body.

static bool lv2_atom_sequence_is_end	(	const LV2_Atom_Sequence_Body *	body,
		uint32_t	size,
		const LV2_Atom_Event *	i
	)		`[inline, static]`

Return true iff `i` has reached the end of `body`.

static LV2_Atom_Event* lv2_atom_sequence_next ( const LV2_Atom_Event * i ) [inline, static]

Return an iterator to the element following `i`.

static void lv2_atom_sequence_clear ( LV2_Atom_Sequence * seq ) [inline, static]

Clear all events from `sequence`.

This simply resets the size field, the other fields are left untouched.

static LV2_Atom_Event* lv2_atom_sequence_append_event	(	LV2_Atom_Sequence *	seq,
		uint32_t	capacity,
		const LV2_Atom_Event *	event
	)		`[inline, static]`

Append an event at the end of `sequence`.

Parameters:

seq	Sequence to append to.
capacity	Total capacity of the sequence atom (e.g. as set by the host for sequence output ports).
event	Event to write.

Returns:: A pointer to the newly written event in `seq`, or NULL on failure (insufficient space).

static LV2_Atom* lv2_atom_tuple_begin ( const LV2_Atom_Tuple * tup ) [inline, static]

Get an iterator pointing to the first element in `tup`.

static bool lv2_atom_tuple_is_end	(	const void *	body,
		uint32_t	size,
		const LV2_Atom *	i
	)		`[inline, static]`

Return true iff `i` has reached the end of `body`.

static LV2_Atom* lv2_atom_tuple_next ( const LV2_Atom * i ) [inline, static]

Return an iterator to the element following `i`.

static LV2_Atom_Property_Body* lv2_atom_object_begin ( const LV2_Atom_Object_Body * body ) [inline, static]

Return a pointer to the first property in `body`.

static bool lv2_atom_object_is_end	(	const LV2_Atom_Object_Body *	body,
		uint32_t	size,
		const LV2_Atom_Property_Body *	i
	)		`[inline, static]`

Return true iff `i` has reached the end of `obj`.

static LV2_Atom_Property_Body* lv2_atom_object_next ( const LV2_Atom_Property_Body * i ) [inline, static]

Return an iterator to the property following `i`.

static int lv2_atom_object_query	(	const LV2_Atom_Object *	object,
		LV2_Atom_Object_Query *	query
	)		`[inline, static]`

Get an object's values for various keys.

The value pointer of each item in `query` will be set to the location of the corresponding value in `object`. Every value pointer in `query` MUST be initialised to NULL. This function reads `object` in a single linear sweep. By allocating `query` on the stack, objects can be "queried" quickly without allocating any memory. This function is realtime safe.

This function can only do "flat" queries, it is not smart enough to match variables in nested objects.

For example:

   const LV2_Atom* name = NULL;
   const LV2_Atom* age  = NULL;
   LV2_Atom_Object_Query q[] = {
       { urids.eg_name, &name },
       { urids.eg_age,  &age },
       LV2_ATOM_OBJECT_QUERY_END
   };
   lv2_atom_object_query(obj, q);
   // name and age are now set to the appropriate values in obj, or NULL.

static int lv2_atom_object_body_get	(	uint32_t	size,
		const LV2_Atom_Object_Body *	body,
			...
	)		`[inline, static]`

Body only version of lv2_atom_object_get().

static int lv2_atom_object_get	(	const LV2_Atom_Object *	object,
			...
	)		`[inline, static]`

Variable argument version of lv2_atom_object_query().

This is nicer-looking in code, but a bit more error-prone since it is not type safe and the argument list must be terminated.

The arguments should be a series of uint32_t key and const LV2_Atom** value pairs, terminated by a zero key. The value pointers MUST be initialized to NULL. For example:

   const LV2_Atom* name = NULL;
   const LV2_Atom* age  = NULL;
   lv2_atom_object_get(obj,
                       uris.name_key, &name,
                       uris.age_key,  &age,
                       0);

Variable Documentation

const LV2_Atom_Object_Query LV2_ATOM_OBJECT_QUERY_END = { 0, NULL } [static]

Data Structures

Functions

Sequence Iterator

Tuple Iterator

Object Iterator

Object Query

Detailed Description

Define Documentation

Function Documentation

Variable Documentation