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authorGravatar Berthold Stoeger <bstoeger@mail.tuwien.ac.at>2020-10-02 19:58:36 +0200
committerGravatar Dirk Hohndel <dirk@hohndel.org>2020-10-03 10:29:15 -0700
commit23da23a53444d555f9211c9c5e6de1fb1bcd27de (patch)
tree6bae55c165306138d7ea486ed0b1475592f097f7 /core
parent34730b898b41b19476eaa61f20273e267d63b7e8 (diff)
downloadsubsurface-23da23a53444d555f9211c9c5e6de1fb1bcd27de.tar.gz
core: add N2 and general gas component accessors
There were helper functions to access O2 and He component fractions. Add another one for N2. Indeed, this can be used in three cases, where N2 was deduced indirectly. Moreover, add a general accessor with a gas_component argument. This will be used by the filter code to filter for gas components. Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
Diffstat (limited to 'core')
-rw-r--r--core/dive.c6
-rw-r--r--core/gas.c17
-rw-r--r--core/gas.h6
3 files changed, 26 insertions, 3 deletions
diff --git a/core/dive.c b/core/dive.c
index f79af7ed2..c3fd95bf1 100644
--- a/core/dive.c
+++ b/core/dive.c
@@ -2065,7 +2065,7 @@ void fill_pressures(struct gas_pressures *pressures, const double amb_pressure,
pressures->o2 = 0;
if (get_o2(mix) != 1000) {
pressures->he = (amb_pressure - pressures->o2) * get_he(mix) / (1000.0 - get_o2(mix));
- pressures->n2 = (amb_pressure - pressures->o2) * (1000 - get_o2(mix) - get_he(mix)) / (1000.0 - get_o2(mix));
+ pressures->n2 = (amb_pressure - pressures->o2) * get_n2(mix) / (1000.0 - get_o2(mix));
} else {
pressures->he = pressures->n2 = 0;
}
@@ -2073,7 +2073,7 @@ void fill_pressures(struct gas_pressures *pressures, const double amb_pressure,
// Open circuit dives: no gas pressure values available, they need to be calculated
pressures->o2 = get_o2(mix) / 1000.0 * amb_pressure; // These calculations are also used if the CCR calculation above..
pressures->he = get_he(mix) / 1000.0 * amb_pressure; // ..returned a po2 of zero (i.e. o2 sensor data not resolvable)
- pressures->n2 = (1000 - get_o2(mix) - get_he(mix)) / 1000.0 * amb_pressure;
+ pressures->n2 = get_n2(mix) / 1000.0 * amb_pressure;
}
}
}
@@ -3760,7 +3760,7 @@ depth_t gas_mnd(struct gasmix mix, depth_t end, const struct dive *dive, int rou
int maxambient = prefs.o2narcotic ?
(int)lrint(ppo2n2.mbar / (1 - get_he(mix) / 1000.0))
:
- (int)lrint(ppo2n2.mbar * N2_IN_AIR / (1000 - get_he(mix) - get_o2(mix)));
+ (int)lrint(ppo2n2.mbar * N2_IN_AIR / get_n2(mix));
rounded_depth.mm = (int)lrint(((double)mbar_to_depth(maxambient, dive)) / roundto) * roundto;
return rounded_depth;
}
diff --git a/core/gas.c b/core/gas.c
index 9f67d0b92..040f938f6 100644
--- a/core/gas.c
+++ b/core/gas.c
@@ -77,3 +77,20 @@ bool gasmix_is_air(struct gasmix gasmix)
int he = gasmix.he.permille;
return (he == 0) && (o2 == 0 || ((o2 >= O2_IN_AIR - 1) && (o2 <= O2_IN_AIR + 1)));
}
+
+static fraction_t make_fraction(int i)
+{
+ fraction_t res;
+ res.permille = i;
+ return res;
+}
+
+fraction_t get_gas_component_fraction(struct gasmix mix, enum gas_component component)
+{
+ switch (component) {
+ case O2: return make_fraction(get_o2(mix));
+ case N2: return make_fraction(get_n2(mix));
+ case HE: return make_fraction(get_he(mix));
+ default: return make_fraction(0);
+ }
+}
diff --git a/core/gas.h b/core/gas.h
index 316f4d3de..c5db7eeff 100644
--- a/core/gas.h
+++ b/core/gas.h
@@ -43,12 +43,18 @@ static inline int get_he(struct gasmix mix)
return mix.he.permille;
}
+static inline int get_n2(struct gasmix mix)
+{
+ return 1000 - get_o2(mix) - get_he(mix);
+}
+
struct gas_pressures {
double o2, n2, he;
};
extern void sanitize_gasmix(struct gasmix *mix);
extern int gasmix_distance(struct gasmix a, struct gasmix b);
+extern fraction_t get_gas_component_fraction(struct gasmix mix, enum gas_component component);
extern bool gasmix_is_air(struct gasmix gasmix);