gserialized_gist_distance_2d()

Datum gserialized_gist_distance_2d

(

PG_FUNCTION_ARGS

)

Definition at line 1203 of file gserialized_gist_2d.c.

References box2df_distance(), box2df_distance_leaf_centroid(), distance(), gserialized_datum_get_box2df_p(), and LW_FAILURE.

Referenced by gserialized_gist_consistent_2d().

{
        GISTENTRY *entry = (GISTENTRY*) PG_GETARG_POINTER(0);
        BOX2DF query_box;
        BOX2DF *entry_box;
        StrategyNumber strategy = (StrategyNumber) PG_GETARG_UINT16(2);
        double distance;
#if POSTGIS_PGSQL_VERSION >= 95
        bool *recheck = (bool *) PG_GETARG_POINTER(4);
#endif

        POSTGIS_DEBUG(4, "[GIST] 'distance' function called");

        /* We are using '13' as the gist true-distance <-> strategy number
        *  and '14' as the gist distance-between-boxes <#> strategy number */
        if ( strategy != 13 && strategy != 14 ) {
                elog(ERROR, "unrecognized strategy number: %d", strategy);
                PG_RETURN_FLOAT8(FLT_MAX);
        }

        /* Null box should never make this far. */
        if ( gserialized_datum_get_box2df_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 = (BOX2DF*)DatumGetPointer(entry->key);

#if POSTGIS_PGSQL_VERSION >= 95

        /* Box-style distance test */
        if ( strategy == 14 ) /* operator <#> */
        {
                distance = box2df_distance(entry_box, &query_box);
        }
        /* True distance test (formerly centroid distance) */
        else if ( strategy == 13 ) /* operator <-> */
        {
                /* In all cases, since we only have keys (boxes) we'll return */
                /* the minimum possible distance, which is the box2df_distance */
                /* and let the recheck sort things out in the case of leaves */
                distance = box2df_distance(entry_box, &query_box);

                if (GIST_LEAF(entry))
                        *recheck = true;
        }
        else
        {
                elog(ERROR, "%s: reached unreachable code", __func__);
                PG_RETURN_NULL();
        }
#else
        /* Box-style distance test */
        if ( strategy == 14 )
        {
                distance = (double)box2df_distance(entry_box, &query_box);
                PG_RETURN_FLOAT8(distance);
        }

        /* Treat leaf node tests different from internal nodes */
        if (GIST_LEAF(entry))
        {
                /* Calculate distance to leaves */
                distance = (double)box2df_distance_leaf_centroid(entry_box, &query_box);
        }
        else
        {
                /* Calculate distance for internal nodes */
                distance = (double)box2df_distance_node_centroid(entry_box, &query_box);
        }
#endif

        PG_RETURN_FLOAT8(distance);
}

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