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author | Berthold Stoeger <bstoeger@mail.tuwien.ac.at> | 2020-10-25 11:36:44 +0100 |
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committer | Dirk Hohndel <dirk@hohndel.org> | 2020-10-25 13:59:52 -0700 |
commit | 464dd93fe8266e3d0af706a6809f09611bd9f83c (patch) | |
tree | 16114568db6e58ad25e14dd76f5a724a7f33d6e8 /core/gas.c | |
parent | 8212acc9925b28ecd546b01047c6a8fc574326ef (diff) | |
download | subsurface-464dd93fe8266e3d0af706a6809f09611bd9f83c.tar.gz |
cleanup: move fill_pressures from dive.c to gas.c
This function does not access a dive structure.
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
Diffstat (limited to 'core/gas.c')
-rw-r--r-- | core/gas.c | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/core/gas.c b/core/gas.c index 757f912b0..128305e12 100644 --- a/core/gas.c +++ b/core/gas.c @@ -94,3 +94,48 @@ fraction_t get_gas_component_fraction(struct gasmix mix, enum gas_component comp default: return make_fraction(0); } } + +/* fill_pressures(): Compute partial gas pressures in bar from gasmix and ambient pressures, possibly for OC or CCR, to be + * extended to PSCT. This function does the calculations of gas pressures applicable to a single point on the dive profile. + * The structure "pressures" is used to return calculated gas pressures to the calling software. + * Call parameters: po2 = po2 value applicable to the record in calling function + * amb_pressure = ambient pressure applicable to the record in calling function + * *pressures = structure for communicating o2 sensor values from and gas pressures to the calling function. + * *mix = structure containing cylinder gas mixture information. + * divemode = the dive mode pertaining to this point in the dive profile. + * This function called by: calculate_gas_information_new() in profile.c; add_segment() in deco.c. + */ +void fill_pressures(struct gas_pressures *pressures, const double amb_pressure, struct gasmix mix, double po2, enum divemode_t divemode) +{ + if ((divemode != OC) && po2) { // This is a rebreather dive where pressures->o2 is defined + if (po2 >= amb_pressure) { + pressures->o2 = amb_pressure; + pressures->n2 = pressures->he = 0.0; + } else { + pressures->o2 = po2; + if (get_o2(mix) == 1000) { + pressures->he = pressures->n2 = 0; + } else { + pressures->he = (amb_pressure - pressures->o2) * (double)get_he(mix) / (1000 - get_o2(mix)); + pressures->n2 = amb_pressure - pressures->o2 - pressures->he; + } + } + } else { + if (divemode == PSCR) { /* The steady state approximation should be good enough */ + pressures->o2 = get_o2(mix) / 1000.0 * amb_pressure - (1.0 - get_o2(mix) / 1000.0) * prefs.o2consumption / (prefs.bottomsac * prefs.pscr_ratio / 1000.0); + if (pressures->o2 < 0) // He's dead, Jim. + 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) * get_n2(mix) / (1000.0 - get_o2(mix)); + } else { + pressures->he = pressures->n2 = 0; + } + } else { + // 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 = get_n2(mix) / 1000.0 * amb_pressure; + } + } +} |