lsup_rdf/include/triple.h

#ifndef _LSUP_TRIPLE_H
#define _LSUP_TRIPLE_H

#include "term.h"

typedef struct LSUP_Triple {
    LSUP_Term *s;
    LSUP_Term *p;
    LSUP_Term *o;
} LSUP_Triple;

typedef struct LSUP_SerTriple {
    LSUP_Buffer *s;
    LSUP_Buffer *p;
    LSUP_Buffer *o;
} LSUP_SerTriple;

typedef enum {
    TRP_POS_S = 0,
    TRP_POS_P = 1,
    TRP_POS_O = 2,
} LSUP_TriplePos;


/** @brief Serialize a RDF triple into a buffer triple.
 *
 * The internal structure must be freed with #LSUP_striple_done after use.
 *
 * @param spo[in] Triple to be serialized.
 * @param sspo[out] Buffer triple handle. It must point to an already allocated
 *  structure.
 *
 * @return LSUP_OK or an error code resulting from #LSUP_term_serialize.
 */
LSUP_rc
LSUP_triple_serialize(const LSUP_Triple *spo, LSUP_SerTriple *sspo);


/** @brief Deserialize a buffer triple into a RDF triple.
 *
 * The internal structure must be freed with #LSUP_triple_done after use.
 *
 * @param sspo[in] Buffer triple to be serialized.
 * @param spo[out] RDF triple handle. It must point to an already allocated
 *  structure.
 *
 * @return LSUP_OK or an error code resulting from #LSUP_term_deserialize.
 */
LSUP_rc
LSUP_triple_deserialize(const LSUP_SerTriple *sspo, LSUP_Triple *spo);


/** @brief Free the internal pointers of a triple.
 *
 * The striple structure itself is not freed, so it can be used with a stack-
 * allocated structure.
 *
 * @param spo[in] Triple to be freed.
 */
void
LSUP_triple_done(LSUP_Triple *spo);


/** @brief Free the internal pointers of a buffer triple.
 *
 * The triple structure itself is not freed, so it can be used with a stack-
 * allocated structure.
 *
 * @param sspo[in] Buffer triple to be freed.
 */
void
LSUP_striple_done(LSUP_SerTriple *sspo);


#define _FN_BODY \
    if (n == TRP_POS_S) return trp->s; \
    if (n == TRP_POS_P) return trp->p; \
    if (n == TRP_POS_O) return trp->o; \
    return NULL;


/** @brief Get triple by term position.
 *
 * Useful for looping over all terms.
 *
 * @param trp[in] Triple pointer.
 *
 * @param n[in] A number between 0÷2.
 *
 * @return Corresponding triple term or NULL if n is out of range.
 */
inline LSUP_Term *
LSUP_triple_pos(const LSUP_Triple *trp, LSUP_TriplePos n)
{ _FN_BODY }


/** @brief Get serialized triple by term position.
 *
 * Useful for looping over all terms.
 *
 * @param trp[in] Serialized triple pointer.
 *
 * @param n[in] A number between 0÷2.
 *
 * @return Corresponding serialized term or NULL if n is out of range.
 */
inline LSUP_Buffer *
LSUP_striple_pos(const LSUP_SerTriple *trp, LSUP_TriplePos n)
{ _FN_BODY }

#undef _FN_BODY


// TODO Add constructors and destructors with term type checks.
#endif