RASTER_summaryStats_finalfn()

Datum RASTER_summaryStats_finalfn

(

PG_FUNCTION_ARGS

)

Definition at line 824 of file rtpg_statistics.c.

{
        rtpg_summarystats_arg state = NULL;
 
        TupleDesc tupdesc;
        HeapTuple tuple;
        Datum values[VALUES_LENGTH];
        bool nulls[VALUES_LENGTH];
        Datum result;
 
        POSTGIS_RT_DEBUG(3, "Starting...");
 
        /* cannot be called directly as this is exclusive aggregate function */
        if (!AggCheckCallContext(fcinfo, NULL)) {
                elog(ERROR, "RASTER_summaryStats_finalfn: Cannot be called in a non-aggregate context");
                PG_RETURN_NULL();
        }
 
        /* NULL, return null */
        if (PG_ARGISNULL(0))
                PG_RETURN_NULL();
 
        state = (rtpg_summarystats_arg) PG_GETARG_POINTER(0);
 
        if (NULL == state) {
                elog(ERROR, "RASTER_summaryStats_finalfn: Cannot compute coverage summary stats");
                PG_RETURN_NULL();
        }
 
        /* coverage mean and deviation */
        if (state->stats->count > 0) {
                state->stats->mean = state->stats->sum / state->stats->count;
                /* sample deviation */
                if (state->stats->sample > 0 && state->stats->sample < 1)
                        state->stats->stddev = sqrt(state->cQ / (state->stats->count - 1));
                /* standard deviation */
                else
                        state->stats->stddev = sqrt(state->cQ / state->stats->count);
        }
 
        /* Build a tuple descriptor for our result type */
        if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE) {
                rtpg_summarystats_arg_destroy(state);
                ereport(ERROR, (
                        errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                        errmsg(
                                "function returning record called in context "
                                "that cannot accept type record"
                        )
                ));
        }
 
        BlessTupleDesc(tupdesc);
 
        memset(nulls, FALSE, sizeof(bool) * VALUES_LENGTH);
 
        values[0] = Int64GetDatum(state->stats->count);
        if (state->stats->count > 0) {
                values[1] = Float8GetDatum(state->stats->sum);
                values[2] = Float8GetDatum(state->stats->mean);
                values[3] = Float8GetDatum(state->stats->stddev);
                values[4] = Float8GetDatum(state->stats->min);
                values[5] = Float8GetDatum(state->stats->max);
        }
        else {
                nulls[1] = TRUE;
                nulls[2] = TRUE;
                nulls[3] = TRUE;
                nulls[4] = TRUE;
                nulls[5] = TRUE;
        }
 
        /* build a tuple */
        tuple = heap_form_tuple(tupdesc, values, nulls);
 
        /* make the tuple into a datum */
        result = HeapTupleGetDatum(tuple);
 
        /* clean up */
        /* For Windowing functions, it is important to leave */
        /* the state intact, knowing that the aggcontext will be */
        /* freed by PgSQL when the statement is complete. */
        /* https://trac.osgeo.org/postgis/ticket/4770 */
        // rtpg_summarystats_arg_destroy(state);
 
        PG_RETURN_DATUM(result);
}

References rt_bandstats_t::count, rtpg_summarystats_arg_t::cQ, FALSE, rt_bandstats_t::max, rt_bandstats_t::mean, rt_bandstats_t::min, POSTGIS_RT_DEBUG, result, rtpg_summarystats_arg_destroy(), rt_bandstats_t::sample, rtpg_summarystats_arg_t::stats, rt_bandstats_t::stddev, rt_bandstats_t::sum, TRUE, and VALUES_LENGTH.

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