rem: if (prev_chain->next == current_chain || !prev_chain->next->tag.data) return (prev_chain);
add: if (prev_chain->tag.type) last_valid = prev_chain; if (prev_chain->next == current_chain) return (last_valid);
context: get_previous_chain (TFB_SoundChain *first_chain, TFB_SoundChain *current_chain){	TFB_SoundChain *prev_chain;	prev_chain = first_chain;	if (prev_chain == current_chain)		return (prev_chain);	while (prev_chain->next)	{		if (prev_chain->next == current_chain || !prev_chain->next->tag.data)			return (prev_chain);		prev_chain = prev_chain->next;	}	return (first_chain);}