Planner: start the ascend with the strongest allowed deco mix.

In analyze_gaslist() we were only keeping gases that had their .depth
above the current depth, i.e. where we could switch to in the future. Now
we take note as well of the strongest gas that we could have already
switched to and switch to it before we attempt to ascend.

[Dirk Hohndel: minor whitespace and code cleanup]

Signed-off-by: Robert C. Helling <helling@atdotde.de>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

1 files changed, 39 insertions, 25 deletions

diff --git a/planner.c b/planner.c
index 48e4609d5..2cc47258c 100644
--- a/planner.c
+++ b/planner.c
@@ -406,37 +406,37 @@ struct gaschanges {
 	int gasidx;
 };
 
-static struct gaschanges *analyze_gaslist(struct diveplan *diveplan, struct dive *dive, int *gaschangenr, int depth)
+
+
+static struct gaschanges *analyze_gaslist(struct diveplan *diveplan, struct dive *dive, int *gaschangenr, int depth, int *asc_cylinder)
 {
 	int nr = 0;
 	struct gaschanges *gaschanges = NULL;
 	struct divedatapoint *dp = diveplan->dp;
-	struct gasmix mix;
-
+	int best_depth = dive->cylinder[*asc_cylinder].depth.mm;
 	while (dp) {
-		if (dp->time == 0 && dp->depth <= depth) {
-			int i = 0, j = 0;
-			nr++;
-			gaschanges = realloc(gaschanges, nr * sizeof(struct gaschanges));
-			while (i < nr - 1) {
-				if (dp->depth < gaschanges[i].depth) {
-					memmove(gaschanges + i + 1, gaschanges + i, (nr - i - 1) * sizeof(struct gaschanges));
-					break;
+		if (dp->time == 0) {
+			if (dp->depth <= depth) {
+				int i = 0;
+				nr++;
+				gaschanges = realloc(gaschanges, nr * sizeof(struct gaschanges));
+				while (i < nr - 1) {
+					if (dp->depth < gaschanges[i].depth) {
+						memmove(gaschanges + i + 1, gaschanges + i, (nr - i - 1) * sizeof(struct gaschanges));
+						break;
+					}
+					i++;
 				}
-				i++;
-			}
-			gaschanges[i].depth = dp->depth;
-			gaschanges[i].gasidx = -1;
-			mix.o2.permille = dp->o2;
-			mix.he.permille = dp->he;
-			do {
-				if (!gasmix_distance(&dive->cylinder[j].gasmix, &mix)) {
-					gaschanges[i].gasidx = j;
-					break;
+				gaschanges[i].depth = dp->depth;
+				gaschanges[i].gasidx = get_gasidx(dive, dp->o2, dp->he);
+				assert(gaschanges[i].gasidx != -1);
+			} else {
+				/* is there a better mix to start deco? */
+				if (dp->depth < best_depth) {
+					best_depth = dp->depth;
+					*asc_cylinder = get_gasidx(dive, dp->o2, dp->he);
 				}
-				j++;
-			} while (j < MAX_CYLINDERS);
-			assert(gaschanges[i].gasidx != -1);
+			}
 		}
 		dp = dp->next;
 	}
@@ -632,6 +632,7 @@ void plan(struct diveplan *diveplan, char **cached_datap, struct dive **divep, s
 	int clock, previous_point_time;
 	int avg_depth, bottom_time;
 	int last_ascend_rate;
+	int best_first_ascend_cylinder;
 
 	set_gf(diveplan->gflow, diveplan->gfhigh, default_prefs.gf_low_at_maxdepth);
 	if (!diveplan->surface_pressure)
@@ -677,8 +678,9 @@ void plan(struct diveplan *diveplan, char **cached_datap, struct dive **divep, s
 	printf("depth %5.2lfm ceiling %5.2lfm\n", depth / 1000.0, ceiling / 1000.0);
 #endif
 
+	best_first_ascend_cylinder = current_cylinder;
 	/* Find the gases available for deco */
-	gaschanges = analyze_gaslist(diveplan, dive, &gaschangenr, depth);
+	gaschanges = analyze_gaslist(diveplan, dive, &gaschangenr, depth, &best_first_ascend_cylinder);
 	/* Find the first potential decostopdepth above current depth */
 	for (stopidx = 0; stopidx < sizeof(decostoplevels) / sizeof(int); stopidx++)
 		if (decostoplevels[stopidx] >= depth)
@@ -693,6 +695,18 @@ void plan(struct diveplan *diveplan, char **cached_datap, struct dive **divep, s
 	bottom_time = clock = previous_point_time = dive->dc.sample[dive->dc.samples - 1].time.seconds;
 	gi = gaschangenr - 1;
 
+	if (best_first_ascend_cylinder != current_cylinder) {
+		stopping = true;
+
+		current_cylinder = best_first_ascend_cylinder;
+		o2 = get_o2(&dive->cylinder[current_cylinder].gasmix);
+		he = get_he(&dive->cylinder[current_cylinder].gasmix);
+#if DEBUG_PLAN & 16
+		printf("switch to gas %d (%d/%d) @ %5.2lfm\n", best_first_ascend_cylinder,
+			       (o2 + 5) / 10, (he + 5) / 10, gaschanges[best_first_ascend_cylinder].depth / 1000.0);
+#endif
+
+	}
 	while (1) {
 		/* We will break out when we hit the surface */
 		do {