From 2804dc42d81a728c62b173f55bbfc075cf643a00 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 3 Sep 2011 13:36:25 -0700 Subject: [PATCH] Only update mean/max depths with computed ones if they are way off The computer may track "real" max depth more closely than it tracks samples. So we trust the non-computed mean/max depths more than the computed ones. Signed-off-by: Linus Torvalds --- dive.c | 29 +++++++++++++++++++++++++++-- 1 file changed, 27 insertions(+), 2 deletions(-) diff --git a/dive.c b/dive.c index 2ecd10c..70d6d42 100644 --- a/dive.c +++ b/dive.c @@ -3,6 +3,30 @@ #include "dive.h" +/* + * So when we re-calculate maxdepth and meandepth, we will + * not override the old numbers if they are close to the + * new ones. + * + * Why? Because a dive computer may well actually track the + * max depth and mean depth at finer granularity than the + * samples it stores. So it's possible that the max and mean + * have been reported more correctly originally. + * + * Only if the values calulcated from the samples are clearly + * different do we override the normal depth values. + * + * This considers 1m to be "clearly different". That's + * a totally random number. + */ +static void update_depth(depth_t *depth, int new) +{ + int old = depth->mm; + + if (abs(old - new) > 1000) + depth->mm = new; +} + struct dive *fixup_dive(struct dive *dive) { int i; @@ -50,15 +74,16 @@ struct dive *fixup_dive(struct dive *dive) return dive; dive->duration.seconds = end - start; if (start != end) - dive->meandepth.mm = depthtime / (end - start); + update_depth(&dive->meandepth, depthtime / (end - start)); if (startpress) dive->beginning_pressure.mbar = startpress; if (endpress) dive->end_pressure.mbar = endpress; if (mintemp) dive->watertemp.mkelvin = mintemp; + if (maxdepth) - dive->maxdepth.mm = maxdepth; + update_depth(&dive->maxdepth, maxdepth); return dive; } -- 2.43.0