Do not copy the memory when the buffer is empty
Do not copy the memory when the buffer is empty

This fixes the following undefined behaviour

converter-example.c:721:13: runtime error: null pointer passed as argument 2, which is declared to never be null
/usr/include/string.h:44:28: note: nonnull attribute specified here

mouse07410/asn1c,mouse07410/asn1c,mouse07410/asn1c,mouse07410/asn1c