gserialized_gist_distance()

Datum gserialized_gist_distance

(

PG_FUNCTION_ARGS

)

Definition at line 1529 of file gserialized_gist_nd.c.

{
        GISTENTRY *entry = (GISTENTRY*) PG_GETARG_POINTER(0);
        StrategyNumber strategy = (StrategyNumber) PG_GETARG_UINT16(2);
        char query_box_mem[GIDX_MAX_SIZE];
        GIDX *query_box = (GIDX*)query_box_mem;
        GIDX *entry_box;
#if POSTGIS_PGSQL_VERSION >= 95
        bool *recheck = (bool *) PG_GETARG_POINTER(4);
#endif
 
        double distance;
 
        POSTGIS_DEBUG(4, "[GIST] 'distance' function called");
 
        /* Strategy 13 is <<->> */
        /* Strategy 20 is |=| */
        if ( strategy != 13 && strategy != 20 ) {
                elog(ERROR, "unrecognized strategy number: %d", strategy);
                PG_RETURN_FLOAT8(FLT_MAX);
        }
 
        /* Null box should never make this far. */
        if ( gserialized_datum_get_gidx_p(PG_GETARG_DATUM(1), query_box) == LW_FAILURE )
        {
                POSTGIS_DEBUG(4, "[GIST] null query_gbox_index!");
                PG_RETURN_FLOAT8(FLT_MAX);
        }
 
        /* Get the entry box */
        entry_box = (GIDX*)DatumGetPointer(entry->key);
 
#if POSTGIS_PGSQL_VERSION >= 95
 
        /* Strategy 20 is |=| */
        distance = gidx_distance(entry_box, query_box, strategy == 20);
 
        /* Treat leaf node tests different from internal nodes */
        if (GIST_LEAF(entry))
                *recheck = true;
#else
 
        if ( strategy == 20 )
        {
                elog(ERROR, "You need PostgreSQL 9.5.0 or higher in order to use |=| with index");
                PG_RETURN_FLOAT8(FLT_MAX);
        }
 
        /* Treat leaf node tests different from internal nodes */
        if (GIST_LEAF(entry))
        {
                /* Calculate distance to leaves */
                distance = (double)gidx_distance_leaf_centroid(entry_box, query_box);
        }
        else
        {
                /* Calculate distance for internal nodes */
                distance = (double)gidx_distance_node_centroid(entry_box, query_box);
        }
#endif
        PG_RETURN_FLOAT8(distance);
}

References distance(), gidx_distance(), and LW_FAILURE.

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