Function bson_to_double_array

pg_documentdb/src/aggregation/bson_tdigest.c:1192–1231

* Transform an input bson to a plain double C array. */

 * Transform an input bson to a plain double C array.
 */
static double *
bson_to_double_array(FunctionCallInfo fcinfo, bson_value_t *barray, int *len)
{
	if (barray->value_type != BSON_TYPE_ARRAY || BsonDocumentValueCountKeys(barray) == 0)
	{
		ereport(ERROR, (errcode(ERRCODE_DOCUMENTDB_LOCATION7750301), errmsg(
							"Expected an array containing numbers from 0.0 to 1.0, but instead received: %s",
							BsonValueToJsonForLogging(barray))));
	}

	(*len) = BsonDocumentValueCountKeys(barray);
	double *result = (double *) palloc((*len) * sizeof(double));
	bson_iter_t iter;
	BsonValueInitIterator(barray, &iter);
	int i = 0;
	while (bson_iter_next(&iter))
	{
		const bson_value_t *value = bson_iter_value(&iter);
		if (!BsonValueIsNumber(value))
		{
			ereport(ERROR, (errcode(ERRCODE_DOCUMENTDB_COMMANDNOTSUPPORTED),
							errmsg(
								"Accumulator $percentile is not implemented yet")));
			ereport(ERROR, (errcode(ERRCODE_DOCUMENTDB_LOCATION7750302), errmsg(
								"Expected an array containing numbers from 0.0 to 1.0, but instead received: %s",
								BsonValueToJsonForLogging(value))));
		}
		double percentile = BsonValueAsDoubleQuiet(bson_iter_value(&iter));
		if (percentile < 0 || percentile > 1)
		{
			ereport(ERROR, (errcode(ERRCODE_DOCUMENTDB_LOCATION7750303), errmsg(
								"Expected an array containing numbers from 0.0 to 1.0, but instead received: %lf",
								percentile)));
		}
		result[i] = percentile;
		i++;
	}

	return result;
}


/*