Practical resource ceilings for stdlib operations whose output size is a function of a numeric argument.

These guard against denial-of-service via a single oversized allocation (e.g. string.rep("x", 1e15), table.unpack(t, 1, 1e12)). Each call site computes the result size before allocating and asks here whether it is permitted, turning what would otherwise be an out-of-memory crash of the host into a catchable Lua error.

PUC-Lua raises the same messages — "resulting string too large" on size_t overflow in str_rep, and "too many results to unpack" on the INT_MAX guard in unpack. The thresholds here sit far above any legitimate embedded use; they are the same guards at a practical bound rather than at the machine word size.

This is the deterministic, OTP-independent layer: it never relies on the garbage collector or heap accounting to notice a bomb, because the bomb is refused before a byte is allocated.