// Package comms validates the data that crosses the wormhole link. The
// content of uplinks and downlinks is opaque bytes defined by the player's
// ship program; only sizes are enforced.
package comms

import "fmt"

func CheckUplink(data []byte, limit int) error {
	if len(data) > limit {
		return fmt.Errorf("uplink is %d bytes, limit is %d", len(data), limit)
	}
	return nil
}

func CheckProgram(prog []byte, limit int) error {
	switch {
	case len(prog) == 0:
		return fmt.Errorf("program is empty")
	case len(prog)%4 != 0:
		return fmt.Errorf("program length %d is not a multiple of 4", len(prog))
	case len(prog) > limit:
		return fmt.Errorf("program is %d bytes, limit is %d", len(prog), limit)
	}
	return nil
}