Remove redundant linear sample tank pressure data

[ext/subsurface.git] / dive.c

diff --git a/dive.c b/dive.c
index cd797d27663f6578ea32ea4cc2ae31a63037bde6..31be3291d76c13647b4dec8607b51636a26eec81 100644 (file)
--- a/dive.c
+++ b/dive.c
@@ -236,7 +236,7 @@ static int same_rounded_pressure(pressure_t a, pressure_t b)
 
 struct dive *fixup_dive(struct dive *dive)
 {
-       int i;
+       int i,j;
        double depthtime = 0;
        int lasttime = 0;
        int lastindex = -1;
@@ -244,6 +244,7 @@ struct dive *fixup_dive(struct dive *dive)
        int maxdepth = 0, mintemp = 0;
        int lastdepth = 0;
        int lasttemp = 0, lastpressure = 0;
+       int pressure_delta[MAX_CYLINDERS] = {INT_MAX, };
 
        for (i = 0; i < dive->samples; i++) {
                struct sample *sample = dive->sample + i;
@@ -253,10 +254,25 @@ struct dive *fixup_dive(struct dive *dive)
                int pressure = sample->cylinderpressure.mbar;
                int index = sample->cylinderindex;
 
-               /* Remove duplicate redundant pressure information */
-               if (pressure == lastpressure && index == lastindex)
-                       sample->cylinderpressure.mbar = 0;
-
+               if (index == lastindex) {
+                       /* Remove duplicate redundant pressure information */
+                       if (pressure == lastpressure)
+                               sample->cylinderpressure.mbar = 0;
+                       /* check for simply linear data in the samples
+                          +INT_MAX means uninitialized, -INT_MAX means not linear */
+                       if (pressure_delta[index] != -INT_MAX && lastpressure) {
+                               if (pressure_delta[index] == INT_MAX) {
+                                       pressure_delta[index] = abs(pressure - lastpressure);
+                               } else {
+                                       int cur_delta = abs(pressure - lastpressure);
+                                       if (cur_delta && abs(cur_delta - pressure_delta[index]) > 150) {
+                                               /* ok the samples aren't just a linearisation
+                                                * between start and end */
+                                               pressure_delta[index] = -INT_MAX;
+                                       }
+                               }
+                       }
+               }
                lastindex = index;
                lastpressure = pressure;
 
@@ -290,6 +306,33 @@ struct dive *fixup_dive(struct dive *dive)
                lastdepth = depth;
                lasttime = time;
        }
+       /* if all the samples for a cylinder have pressure data that
+        * is basically equidistant throw out the sample cylinder pressure
+        * information but make sure we still have a valid start and end
+        * pressure
+        * this happens when DivingLog decides to linearalize the
+        * pressure between beginning and end and for strange reasons
+        * decides to put that in the sample data as if it came from
+        * the dive computer; we don't want that (we'll visualize with
+        * constant SAC rate instead)
+        * WARNING WARNING - I have only seen this in single tank dives
+        * --- maybe I should try to create a multi tank dive and see what
+        * --- divinglog does there - but the code right now is only tested
+        * --- for the single tank case */
+       for (j = 0; j < MAX_CYLINDERS; j++) {
+               if (abs(pressure_delta[j]) != INT_MAX) {
+                       cylinder_t *cyl = dive->cylinder + j;
+                       for (i = 0; i < dive->samples; i++)
+                               if (dive->sample[i].cylinderindex == j)
+                                       dive->sample[i].cylinderpressure.mbar = 0;
+                       if (! cyl->start.mbar)
+                               cyl->start.mbar = cyl->sample_start.mbar;
+                       if (! cyl->end.mbar)
+                               cyl->end.mbar = cyl->sample_end.mbar;
+                       cyl->sample_start.mbar = 0;
+                       cyl->sample_end.mbar = 0;
+               }
+       }
        if (end < 0)
                return dive;