RASTER_pixelOfValue()

Datum RASTER_pixelOfValue

(

PG_FUNCTION_ARGS

)

Definition at line 1817 of file rtpg_pixel.c.

{
        FuncCallContext *funcctx;
        TupleDesc tupdesc;
 
        rt_pixel pixels = NULL;
        rt_pixel pixels2 = NULL;
        int count = 0;
        int i = 0;
        int n = 0;
        int call_cntr;
        int max_calls;
 
        if (SRF_IS_FIRSTCALL()) {
                MemoryContext oldcontext;
 
                rt_pgraster *pgraster = NULL;
                rt_raster raster = NULL;
                rt_band band = NULL;
                int nband = 1;
                int num_bands = 0;
                double *search = NULL;
                int nsearch = 0;
                double val;
                bool exclude_nodata_value = TRUE;
 
                ArrayType *array;
                Oid etype;
                Datum *e;
                bool *nulls;
                int16 typlen;
                bool typbyval;
                char typalign;
 
                /* create a function context for cross-call persistence */
                funcctx = SRF_FIRSTCALL_INIT();
 
                /* switch to memory context appropriate for multiple function calls */
                oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
 
                if (PG_ARGISNULL(0)) {
                        MemoryContextSwitchTo(oldcontext);
                        SRF_RETURN_DONE(funcctx);
                }
                pgraster = (rt_pgraster *) PG_DETOAST_DATUM(PG_GETARG_DATUM(0));
                raster = rt_raster_deserialize(pgraster, FALSE);
                if (!raster) {
                        PG_FREE_IF_COPY(pgraster, 0);
                        MemoryContextSwitchTo(oldcontext);
                        elog(ERROR, "RASTER_pixelOfValue: Could not deserialize raster");
                        SRF_RETURN_DONE(funcctx);
                }
 
                /* num_bands */
                num_bands = rt_raster_get_num_bands(raster);
                if (num_bands < 1) {
                        elog(NOTICE, "Raster provided has no bands");
                        rt_raster_destroy(raster);
                        PG_FREE_IF_COPY(pgraster, 0);
                        MemoryContextSwitchTo(oldcontext);
                        SRF_RETURN_DONE(funcctx);
                }
 
                /* band index is 1-based */
                if (!PG_ARGISNULL(1))
                        nband = PG_GETARG_INT32(1);
                if (nband < 1 || nband > num_bands) {
                        elog(NOTICE, "Invalid band index (must use 1-based). Returning NULL");
                        rt_raster_destroy(raster);
                        PG_FREE_IF_COPY(pgraster, 0);
                        MemoryContextSwitchTo(oldcontext);
                        SRF_RETURN_DONE(funcctx);
                }
 
                /* search values */
                array = PG_GETARG_ARRAYTYPE_P(2);
                etype = ARR_ELEMTYPE(array);
                get_typlenbyvalalign(etype, &typlen, &typbyval, &typalign);
 
                switch (etype) {
                        case FLOAT4OID:
                        case FLOAT8OID:
                                break;
                        default:
                                rt_raster_destroy(raster);
                                PG_FREE_IF_COPY(pgraster, 0);
                                MemoryContextSwitchTo(oldcontext);
                                elog(ERROR, "RASTER_pixelOfValue: Invalid data type for pixel values");
                                SRF_RETURN_DONE(funcctx);
                                break;
                }
 
                deconstruct_array(array, etype, typlen, typbyval, typalign, &e,
                        &nulls, &n);
 
                search = palloc(sizeof(double) * n);
                for (i = 0, nsearch = 0; i < n; i++) {
                        if (nulls[i]) continue;
 
                        switch (etype) {
                                case FLOAT4OID:
                                        val = (double) DatumGetFloat4(e[i]);
                                        break;
                                case FLOAT8OID:
                                        val = (double) DatumGetFloat8(e[i]);
                                        break;
                        }
 
                        search[nsearch] = val;
                        POSTGIS_RT_DEBUGF(3, "search[%d] = %f", nsearch, search[nsearch]);
                        nsearch++;
                }
 
                /* not searching for anything */
                if (nsearch < 1) {
                        elog(NOTICE, "No search values provided. Returning NULL");
                        pfree(search);
                        rt_raster_destroy(raster);
                        PG_FREE_IF_COPY(pgraster, 0);
                        MemoryContextSwitchTo(oldcontext);
                        SRF_RETURN_DONE(funcctx);
                }
                else if (nsearch < n)
                        search = repalloc(search, sizeof(double) * nsearch);
 
                /* exclude_nodata_value flag */
                if (!PG_ARGISNULL(3))
                        exclude_nodata_value = PG_GETARG_BOOL(3);
 
                /* get band */
                band = rt_raster_get_band(raster, nband - 1);
                if (!band) {
                        elog(NOTICE, "Could not find band at index %d. Returning NULL", nband);
                        rt_raster_destroy(raster);
                        PG_FREE_IF_COPY(pgraster, 0);
                        MemoryContextSwitchTo(oldcontext);
                        SRF_RETURN_DONE(funcctx);
                }
 
                /* get pixels of values */
                count = rt_band_get_pixel_of_value(
                        band, exclude_nodata_value,
                        search, nsearch,
                        &pixels
                );
                pfree(search);
                rt_band_destroy(band);
                rt_raster_destroy(raster);
                PG_FREE_IF_COPY(pgraster, 0);
                if (count < 1) {
                        /* error */
                        if (count < 0)
                                elog(NOTICE, "Could not get the pixels of search values for band at index %d", nband);
                        /* no nearest pixel */
                        else
                                elog(NOTICE, "No pixels of search values found for band at index %d", nband);
 
                        MemoryContextSwitchTo(oldcontext);
                        SRF_RETURN_DONE(funcctx);
                }
 
                /* Store needed information */
                funcctx->user_fctx = pixels;
 
                /* total number of tuples to be returned */
                funcctx->max_calls = count;
 
                /* Build a tuple descriptor for our result type */
                if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE) {
                        ereport(ERROR, (
                                errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                                errmsg(
                                        "function returning record called in context "
                                        "that cannot accept type record"
                                )
                        ));
                }
 
                BlessTupleDesc(tupdesc);
                funcctx->tuple_desc = tupdesc;
 
                MemoryContextSwitchTo(oldcontext);
        }
 
        /* stuff done on every call of the function */
        funcctx = SRF_PERCALL_SETUP();
 
        call_cntr = funcctx->call_cntr;
        max_calls = funcctx->max_calls;
        tupdesc = funcctx->tuple_desc;
        pixels2 = funcctx->user_fctx;
 
        /* do when there is more left to send */
        if (call_cntr < max_calls) {
                Datum values[VALUES_LENGTH];
                bool nulls[VALUES_LENGTH];
                HeapTuple tuple;
                Datum result;
 
                memset(nulls, FALSE, sizeof(bool) * VALUES_LENGTH);
 
                /* 0-based to 1-based */
                pixels2[call_cntr].x += 1;
                pixels2[call_cntr].y += 1;
 
                values[0] = Float8GetDatum(pixels2[call_cntr].value);
                values[1] = Int32GetDatum(pixels2[call_cntr].x);
                values[2] = Int32GetDatum(pixels2[call_cntr].y);
 
                /* build a tuple */
                tuple = heap_form_tuple(tupdesc, values, nulls);
 
                /* make the tuple into a datum */
                result = HeapTupleGetDatum(tuple);
 
                SRF_RETURN_NEXT(funcctx, result);
        }
        else {
                pfree(pixels2);
                SRF_RETURN_DONE(funcctx);
        }
}

References FALSE, POSTGIS_RT_DEBUGF, result, rt_band_destroy(), rt_band_get_pixel_of_value(), rt_raster_deserialize(), rt_raster_destroy(), rt_raster_get_band(), rt_raster_get_num_bands(), TRUE, VALUES_LENGTH, rt_pixel_t::x, and rt_pixel_t::y.

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