Sratom 0.6.16 documentation

# Sratom

Sratom is a small library for serializing LV2 atoms. Sratom reads/writes atoms from/to RDF, allowing them to be converted between binary and text or stored in a model.

## Overview

The complete API is declared in `sratom.h`:

    #include <sratom/sratom.h>

## Sratom C API

enum SratomObjectMode

  Mode for reading resources to LV2 Objects.

  This affects how resources (which are either blank nodes or have URIs) are read by `sratom_read()`, since they may be read as simple references (a URI or blank node ID) or a complete description (an atom “Object”).

  Currently, blank nodes are always read as Objects, but support for reading blank node IDs may be added in the future.

  enumerator SRATOM_OBJECT_MODE_BLANK

    Read blank nodes as Objects, and named resources as URIs.

  enumerator SRATOM_OBJECT_MODE_BLANK_SUBJECT

    Read blank nodes and the main subject as Objects.

    Any other named resources are read as URIs. The “main subject” is the subject parameter passed to `sratom_read()`; if this is a resource it will be read as an Object, but all other named resources encountered will be read as URIs.

typedef struct SratomImpl Sratom

  Atom serializer.

Sratom *sratom_new(LV2_URID_Map *map)

  Create a new Atom serializer.

void sratom_free(Sratom *sratom)

  Free an Atom serializer.

void sratom_set_env(Sratom *sratom, SerdEnv *env)

  Set the environment for reading or writing Turtle.

  This can be used to set namespace prefixes and a base URI for `sratom_to_turtle()` and `sratom_from_turtle()`.

void sratom_set_sink(Sratom *sratom, const char *base_uri, SerdStatementSink sink, SerdEndSink end_sink, void *handle)

  Set the sink(s) where sratom will write its output.

  This must be called before calling `sratom_write()`.

void sratom_set_pretty_numbers(Sratom *sratom, bool pretty_numbers)

  Write pretty numeric literals.

  If `pretty_numbers` is true, numbers will be written as pretty Turtle literals, rather than string literals with precise types. The cost of this is that the types might get fudged on a round-trip to RDF and back.

void sratom_set_object_mode(Sratom *sratom, SratomObjectMode object_mode)

  Configure how resources will be read to form LV2 Objects.

int sratom_write(Sratom *sratom, LV2_URID_Unmap *unmap, uint32_t flags, const SerdNode *subject, const SerdNode *predicate, uint32_t type_urid, uint32_t size, const void *body)

  Write an Atom to RDF.

  The serialized atom is written to the sink set by `sratom_set_sink()`.

  Returns:

    0 on success, or a non-zero error code otherwise.

void sratom_read(Sratom *sratom, LV2_Atom_Forge *forge, SordWorld *world, SordModel *model, const SordNode *node)

  Read an Atom from RDF.

  The resulting atom will be written to `forge`.

char *sratom_to_turtle(Sratom *sratom, LV2_URID_Unmap *unmap, const char *base_uri, const SerdNode *subject, const SerdNode *predicate, uint32_t type, uint32_t size, const void *body)

  Serialize an Atom to a Turtle string.

  The returned string must be free()’d by the caller.

LV2_Atom *sratom_from_turtle(Sratom *sratom, const char *base_uri, const SerdNode *subject, const SerdNode *predicate, const char *str)

  Read an Atom from a Turtle string.

  The returned atom must be free()’d by the caller.

LV2_Atom_Forge_Ref sratom_forge_sink(LV2_Atom_Forge_Sink_Handle handle, const void *buf, uint32_t size)

  A convenient resizing sink for LV2_Atom_Forge.

  The handle must point to an initialized SerdChunk.

LV2_Atom *sratom_forge_deref(LV2_Atom_Forge_Sink_Handle handle, LV2_Atom_Forge_Ref ref)

  The corresponding deref function for sratom_forge_sink.