Interpretive dance to parse Suunto EON Steel tank sizes

Admittedly, imperial tank sizes are a bit weird.

But it must have taken some effort to break things as creatievly as Suunto did.
The UI allows only multiples of 100psi and multiples of 10cuft. Which shows
that the developers have no idea what typical imperial tanks look like. AL72?
AL63? HP tanks at 3440psi? LP+ at 2640psi?

Yeah, I get it - you had no idea, someone showed you an AL80 and you made silly
assumptions.

But even then, what the heck are you storing in your data, dear Suunto? The
pressures are off by the very logical factor of 1.00069182389937. And then
regardless whether I use the wrong pressure or the corrected pressure, the wet
sizes are too small by a non-constant factor.

So this code takes the junk that libdivecomputer truthfully passes through from
the Suunto parser and tries to convert it into something that matches what the
user most likely entered in the EON Steel UI. Ugly. Stupid. But it seems to
work.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

1 files changed, 33 insertions, 0 deletions

diff --git a/libdivecomputer.c b/libdivecomputer.c
index 26f5e59bd..a9d90d837 100644
--- a/libdivecomputer.c
+++ b/libdivecomputer.c
@@ -126,6 +126,39 @@ static int parse_gasmixes(device_data_t *devdata, struct dive *dive, dc_parser_t
 				if (tank.type == DC_TANKVOLUME_IMPERIAL) {
 					dive->cylinder[i].type.size.mliter = rint(tank.volume * 1000);
 					dive->cylinder[i].type.workingpressure.mbar = rint(tank.workpressure * 1000);
+					if (same_string(devdata->model, "Suunto EON Steel")) {
+						/* Suunto EON Steele gets this wrong. Badly.
+						 * but on the plus side it only supports a few imperial sizes,
+						 * so let's try and guess at least the most common ones.
+						 * First, the pressures are off by a constant factor. WTF?
+						 * Then we can round the wet sizes so we get to multiples of 10
+						 * for cuft sizes (as that's all that you can enter) */
+						dive->cylinder[i].type.workingpressure.mbar *= 206.843 / 206.7;
+						char name_buffer[9];
+						int rounded_size = ml_to_cuft(gas_volume(&dive->cylinder[i],
+											 dive->cylinder[i].type.workingpressure));
+						rounded_size = (int)((rounded_size + 5) / 10) * 10;
+						switch (dive->cylinder[i].type.workingpressure.mbar) {
+						case 206843:
+							snprintf(name_buffer, 9, "AL%d", rounded_size);
+							break;
+						case 234422: /* this is wrong - HP tanks tend to be 3440, but Suunto only allows 3400 */
+							snprintf(name_buffer, 9, "HP%d", rounded_size);
+							break;
+						case 179263:
+							snprintf(name_buffer, 9, "LP+%d", rounded_size);
+							break;
+						case 165474:
+							snprintf(name_buffer, 9, "LP%d", rounded_size);
+							break;
+						default:
+							snprintf(name_buffer, 9, "%d cuft", rounded_size);
+							break;
+						}
+						dive->cylinder[i].type.description = copy_string(name_buffer);
+						dive->cylinder[i].type.size.mliter = cuft_to_l(rounded_size) * 1000 /
+										     mbar_to_atm(dive->cylinder[i].type.workingpressure.mbar);
+					}
 				} else if (tank.type == DC_TANKVOLUME_METRIC) {
 					dive->cylinder[i].type.size.mliter = rint(tank.volume * 1000);
 				}