RASTER_summaryStats_transfn()

Datum RASTER_summaryStats_transfn

(

PG_FUNCTION_ARGS

)

Definition at line 562 of file rtpg_statistics.c.

{
        MemoryContext aggcontext;
        MemoryContext oldcontext;
        rtpg_summarystats_arg state = NULL;
        bool skiparg = FALSE;
 
        int i = 0;
 
        rt_pgraster *pgraster = NULL;
        rt_raster raster = NULL;
        rt_band band = NULL;
        int num_bands = 0;
        rt_bandstats stats = NULL;
 
        POSTGIS_RT_DEBUG(3, "Starting...");
 
        /* cannot be called directly as this is exclusive aggregate function */
        if (!AggCheckCallContext(fcinfo, &aggcontext)) {
                elog(
                        ERROR,
                        "RASTER_summaryStats_transfn: Cannot be called in a non-aggregate context"
                );
                PG_RETURN_NULL();
        }
 
        /* switch to aggcontext */
        oldcontext = MemoryContextSwitchTo(aggcontext);
 
        if (PG_ARGISNULL(0)) {
                POSTGIS_RT_DEBUG(3, "Creating state variable");
 
                state = rtpg_summarystats_arg_init();
                if (state == NULL) {
                        MemoryContextSwitchTo(oldcontext);
                        elog(
                                ERROR,
                                "RASTER_summaryStats_transfn: Cannot allocate memory for state variable"
                        );
                        PG_RETURN_NULL();
                }
 
                skiparg = FALSE;
        }
        else {
                POSTGIS_RT_DEBUG(3, "State variable already exists");
                state = (rtpg_summarystats_arg) PG_GETARG_POINTER(0);
                skiparg = TRUE;
        }
 
        /* raster arg is NOT NULL */
        if (!PG_ARGISNULL(1)) {
                /* deserialize raster */
                pgraster = (rt_pgraster *) PG_DETOAST_DATUM(PG_GETARG_DATUM(1));
 
                /* Get raster object */
                raster = rt_raster_deserialize(pgraster, FALSE);
                if (raster == NULL) {
 
                        rtpg_summarystats_arg_destroy(state);
                        PG_FREE_IF_COPY(pgraster, 1);
 
                        MemoryContextSwitchTo(oldcontext);
                        elog(ERROR, "RASTER_summaryStats_transfn: Cannot deserialize raster");
                        PG_RETURN_NULL();
                }
        }
 
        do {
                Oid calltype;
                int nargs = 0;
 
                if (skiparg)
                        break;
 
                /* 4 or 5 total possible args */
                nargs = PG_NARGS();
                POSTGIS_RT_DEBUGF(4, "nargs = %d", nargs);
 
                for (i = 2; i < nargs; i++) {
                        if (PG_ARGISNULL(i))
                                continue;
 
                        calltype = get_fn_expr_argtype(fcinfo->flinfo, i);
 
                        /* band index */
                        if (
                                (calltype == INT2OID || calltype == INT4OID) &&
                                i == 2
                        ) {
                                if (calltype == INT2OID)
                                        state->band_index = PG_GETARG_INT16(i);
                                else
                                        state->band_index = PG_GETARG_INT32(i);
 
                                /* basic check, > 0 */
                                if (state->band_index < 1) {
 
                                        rtpg_summarystats_arg_destroy(state);
                                        if (raster != NULL) {
                                                rt_raster_destroy(raster);
                                                PG_FREE_IF_COPY(pgraster, 1);
                                        }
 
                                        MemoryContextSwitchTo(oldcontext);
                                        elog(
                                                ERROR,
                                                "RASTER_summaryStats_transfn: Invalid band index (must use 1-based). Returning NULL"
                                        );
                                        PG_RETURN_NULL();
                                }
                        }
                        /* exclude_nodata_value */
                        else if (
                                calltype == BOOLOID && (
                                        i == 2 || i == 3
                                )
                        ) {
                                state->exclude_nodata_value = PG_GETARG_BOOL(i);
                        }
                        /* sample rate */
                        else if (
                                (calltype == FLOAT4OID || calltype == FLOAT8OID) &&
                                (i == 3 || i == 4)
                        ) {
                                if (calltype == FLOAT4OID)
                                        state->sample = PG_GETARG_FLOAT4(i);
                                else
                                        state->sample = PG_GETARG_FLOAT8(i);
 
                                /* basic check, 0 <= sample <= 1 */
                                if (state->sample < 0. || state->sample > 1.) {
 
                                        rtpg_summarystats_arg_destroy(state);
                                        if (raster != NULL) {
                                                rt_raster_destroy(raster);
                                                PG_FREE_IF_COPY(pgraster, 1);
                                        }
 
                                        MemoryContextSwitchTo(oldcontext);
                                        elog(
                                                ERROR,
                                                "Invalid sample percentage (must be between 0 and 1). Returning NULL"
                                        );
 
                                        PG_RETURN_NULL();
                                }
                                else if (FLT_EQ(state->sample, 0.0))
                                        state->sample = 1;
                        }
                        /* unknown arg */
                        else {
                                rtpg_summarystats_arg_destroy(state);
                                if (raster != NULL) {
                                        rt_raster_destroy(raster);
                                        PG_FREE_IF_COPY(pgraster, 1);
                                }
 
                                MemoryContextSwitchTo(oldcontext);
                                elog(
                                        ERROR,
                                        "RASTER_summaryStats_transfn: Unknown function parameter at index %d",
                                        i
                                );
                                PG_RETURN_NULL();
                        }
                }
        }
        while (0);
 
        /* null raster, return */
        if (PG_ARGISNULL(1)) {
                POSTGIS_RT_DEBUG(4, "NULL raster so processing required");
                MemoryContextSwitchTo(oldcontext);
                PG_RETURN_POINTER(state);
        }
 
        /* inspect number of bands */
        num_bands = rt_raster_get_num_bands(raster);
        if (state->band_index > num_bands) {
                elog(
                        NOTICE,
                        "Raster does not have band at index %d. Skipping raster",
                        state->band_index
                );
 
                rt_raster_destroy(raster);
                PG_FREE_IF_COPY(pgraster, 1);
 
                MemoryContextSwitchTo(oldcontext);
                PG_RETURN_POINTER(state);
        }
 
        /* get band */
        band = rt_raster_get_band(raster, state->band_index - 1);
        if (!band) {
                elog(
                        NOTICE, "Cannot find band at index %d. Skipping raster",
                        state->band_index
                );
 
                rt_raster_destroy(raster);
                PG_FREE_IF_COPY(pgraster, 1);
 
                MemoryContextSwitchTo(oldcontext);
                PG_RETURN_POINTER(state);
        }
 
        /* we don't need the raw values, hence the zero parameter */
        stats = rt_band_get_summary_stats(
                band, (int) state->exclude_nodata_value,
                state->sample, 0,
                &(state->cK), &(state->cM), &(state->cQ)
        );
 
        rt_band_destroy(band);
        rt_raster_destroy(raster);
        PG_FREE_IF_COPY(pgraster, 1);
 
        if (NULL == stats) {
                elog(
                        NOTICE,
                        "Cannot compute summary statistics for band at index %d. Returning NULL",
                        state->band_index
                );
 
                rtpg_summarystats_arg_destroy(state);
 
                MemoryContextSwitchTo(oldcontext);
                PG_RETURN_NULL();
        }
 
        if (stats->count > 0) {
                if (state->stats->count < 1) {
                        state->stats->sample = stats->sample;
                        state->stats->count = stats->count;
                        state->stats->min = stats->min;
                        state->stats->max = stats->max;
                        state->stats->sum = stats->sum;
                        state->stats->mean = stats->mean;
                        state->stats->stddev = -1;
                }
                else {
                        state->stats->count += stats->count;
                        state->stats->sum += stats->sum;
 
                        if (stats->min < state->stats->min)
                                state->stats->min = stats->min;
                        if (stats->max > state->stats->max)
                                state->stats->max = stats->max;
                }
        }
 
        pfree(stats);
 
        /* switch back to local context */
        MemoryContextSwitchTo(oldcontext);
 
        POSTGIS_RT_DEBUG(3, "Finished");
 
        PG_RETURN_POINTER(state);
}

References rtpg_summarystats_arg_t::band_index, rtpg_summarystats_arg_t::cK, rtpg_summarystats_arg_t::cM, rt_bandstats_t::count, rtpg_summarystats_arg_t::cQ, rtpg_summarystats_arg_t::exclude_nodata_value, FALSE, FLT_EQ, rt_bandstats_t::max, rt_bandstats_t::mean, rt_bandstats_t::min, POSTGIS_RT_DEBUG, POSTGIS_RT_DEBUGF, rt_band_destroy(), rt_band_get_summary_stats(), rt_raster_deserialize(), rt_raster_destroy(), rt_raster_get_band(), rt_raster_get_num_bands(), rtpg_summarystats_arg_destroy(), rtpg_summarystats_arg_init(), rt_bandstats_t::sample, rtpg_summarystats_arg_t::sample, rtpg_summarystats_arg_t::stats, rt_bandstats_t::stddev, rt_bandstats_t::sum, and TRUE.

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