Function ArrayCheckBounds

src/backend/utils/adt/arrayutils.c:121–137

* Verify sanity of proposed lower-bound values for an array * * The lower-bound values must not be so large as to cause overflow when * calculating subscripts, e.g. lower bound 2147483640 with length 10 * must be disallowed. We actually insist that dims[i] + lb[i] be * computable without overflow, meaning that an array with last subscript * equal to INT_MAX will be disallowed. * * It is a

 * overflowed (negative) dims[] values have been eliminated.
 */
void
ArrayCheckBounds(int ndim, const int *dims, const int *lb)
{
	int			i;

	for (i = 0; i < ndim; i++)
	{
		/* PG_USED_FOR_ASSERTS_ONLY prevents variable-isn't-read warnings */
		int32		sum PG_USED_FOR_ASSERTS_ONLY;

		if (pg_add_s32_overflow(dims[i], lb[i], &sum))
			ereport(ERROR,
					(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
					 errmsg("array lower bound is too large: %d",
							lb[i])));
	}
}

/*
 * Compute ranges (sub-array dimensions) for an array slice