[PATCH] Rewrite is_gas_used to use get_cylinder_index

[Dirk Hohndel]

That will require a little more "staring at it" to convince myself that
this is really equivalent...

Maybe you could expand on the commit message a bit?

Thanks

/D

On Fri, 2013-11-29 at 00:40 +0100, Anton Lundin wrote:
> get_cylinder_index implements a algorithm to map gaschange events to gas
> idx. This is a bit clumsy to use it to map if a gas idx have bin used,
> but its consistent with other parts.
> 
> Signed-off-by: Anton Lundin <glance at acc.umu.se>
> ---
>  statistics.c | 44 ++++++++++----------------------------------
>  1 file changed, 10 insertions(+), 34 deletions(-)
> 
> diff --git a/statistics.c b/statistics.c
> index c4beba3..807539f 100644
> --- a/statistics.c
> +++ b/statistics.c
> @@ -295,49 +295,25 @@ void get_selected_dives_text(char *buffer, int size)
>  
>  bool is_gas_used(struct dive *dive, int idx)
>  {
> -	cylinder_t *cyl = &dive->cylinder[idx];
> -	int o2, he;
> -	struct divecomputer *dc;
> -	bool used = FALSE;
> +	struct divecomputer *dc = &dive->dc;
>  	bool firstGasExplicit = FALSE;
> -	if (cylinder_none(cyl))
> +	if (cylinder_none(&dive->cylinder[idx]))
>  		return FALSE;
>  
> -	o2 = get_o2(&cyl->gasmix);
> -	he = get_he(&cyl->gasmix);
> -	dc = &dive->dc;
>  	while (dc) {
> -		struct event *event = dc->events;
> +		struct event *event = get_next_event(dc->events, "gaschange");
>  		while (event) {
> -			if (event->value) {
> -				if (event->name && !strcmp(event->name, "gaschange")) {
> -					unsigned int event_he = event->value >> 16;
> -					unsigned int event_o2 = event->value & 0xffff;
> -					if (event->time.seconds < 30)
> -						firstGasExplicit = TRUE;
> -					if (is_air(o2, he)) {
> -						if (is_air(event_o2 * 10, event_he * 10))
> -							used = TRUE;
> -					} else if (event->type == 25 && he == event_he * 10 && o2 == event_o2 * 10) {
> -						/* SAMPLE_EVENT_GASCHANGE2(25) contains both o2 and he */
> -						used = TRUE;
> -					} else if (o2 == event_o2 * 10) {
> -						/* SAMPLE_EVENT_GASCHANGE(11) only contains o2 */
> -						used = TRUE;
> -					}
> -				}
> -			}
> -			if (used)
> -				break;
> -			event = event->next;
> +			if (event->time.seconds < 30)
> +				firstGasExplicit = TRUE;
> +			if (get_cylinder_index(dive, event) == idx)
> +				return TRUE;
> +			event = get_next_event(event->next, "gaschange");
>  		}
> -		if (used)
> -			break;
>  		dc = dc->next;
>  	}
>  	if (idx == 0 && !firstGasExplicit)
> -		used = TRUE;
> -	return used;
> +		return TRUE;
> +	return FALSE;
>  }
>  
>  void get_gas_used(struct dive *dive, volume_t gases[MAX_CYLINDERS])