Function array_position_common

src/backend/utils/adt/array_userfuncs.c:1496–1634

* array_position_common * Common code for array_position and array_position_start * * These are separate wrappers for the sake of opr_sanity regression test. * They are not strict so we have to test for null inputs explicitly. */

 * They are not strict so we have to test for null inputs explicitly.
 */
static Datum
array_position_common(FunctionCallInfo fcinfo)
{
	ArrayType  *array;
	Oid			collation = PG_GET_COLLATION();
	Oid			element_type;
	Datum		searched_element,
				value;
	bool		isnull;
	int			position,
				position_min;
	bool		found = false;
	TypeCacheEntry *typentry;
	ArrayMetaState *my_extra;
	bool		null_search;
	ArrayIterator array_iterator;

	if (PG_ARGISNULL(0))
		PG_RETURN_NULL();

	array = PG_GETARG_ARRAYTYPE_P(0);
	element_type = ARR_ELEMTYPE(array);

	/*
	 * We refuse to search for elements in multi-dimensional arrays, since we
	 * have no good way to report the element's location in the array.
	 */
	if (ARR_NDIM(array) > 1)
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				 errmsg("searching for elements in multidimensional arrays is not supported")));

	if (PG_ARGISNULL(1))
	{
		/* fast return when the array doesn't have nulls */
		if (!array_contains_nulls(array))
			PG_RETURN_NULL();
		searched_element = (Datum) 0;
		null_search = true;
	}
	else
	{
		searched_element = PG_GETARG_DATUM(1);
		null_search = false;
	}

	position = (ARR_LBOUND(array))[0] - 1;

	/* figure out where to start */
	if (PG_NARGS() == 3)
	{
		if (PG_ARGISNULL(2))
			ereport(ERROR,
					(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
					 errmsg("initial position must not be null")));

		position_min = PG_GETARG_INT32(2);
	}