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authorGravatar Dirk Hohndel <dirk@hohndel.org>2016-04-04 22:02:03 -0700
committerGravatar Dirk Hohndel <dirk@hohndel.org>2016-04-04 22:33:58 -0700
commit7be962bfc2879a72c32ff67518731347dcdff6de (patch)
treed05bf7ab234a448ee37a15b608e2b939f2285d07 /core/gaspressures.c
parent2d760a7bff71c46c5aeba37c40d236ea16eefea2 (diff)
downloadsubsurface-7be962bfc2879a72c32ff67518731347dcdff6de.tar.gz
Move subsurface-core to core and qt-mobile to mobile-widgets
Having subsurface-core as a directory name really messes with autocomplete and is obviously redundant. Simmilarly, qt-mobile caused an autocomplete conflict and also was inconsistent with the desktop-widget name for the directory containing the "other" UI. And while cleaning up the resulting change in the path name for include files, I decided to clean up those even more to make them consistent overall. This could have been handled in more commits, but since this requires a make clean before the build, it seemed more sensible to do it all in one. Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Diffstat (limited to 'core/gaspressures.c')
-rw-r--r--core/gaspressures.c430
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diff --git a/core/gaspressures.c b/core/gaspressures.c
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+/* gaspressures.c
+ * ---------------
+ * This file contains the routines to calculate the gas pressures in the cylinders.
+ * The functions below support the code in profile.c.
+ * The high-level function is populate_pressure_information(), called by function
+ * create_plot_info_new() in profile.c. The other functions below are, in turn,
+ * called by populate_pressure_information(). The calling sequence is as follows:
+ *
+ * populate_pressure_information() -> calc_pressure_time()
+ * -> fill_missing_tank_pressures() -> fill_missing_segment_pressures()
+ * -> get_pr_interpolate_data()
+ *
+ * The pr_track_t related functions below implement a linked list that is used by
+ * the majority of the functions below. The linked list covers a part of the dive profile
+ * for which there are no cylinder pressure data. Each element in the linked list
+ * represents a segment between two consecutive points on the dive profile.
+ * pr_track_t is defined in gaspressures.h
+ */
+
+#include "dive.h"
+#include "display.h"
+#include "profile.h"
+#include "gaspressures.h"
+
+static pr_track_t *pr_track_alloc(int start, int t_start)
+{
+ pr_track_t *pt = malloc(sizeof(pr_track_t));
+ pt->start = start;
+ pt->end = 0;
+ pt->t_start = pt->t_end = t_start;
+ pt->pressure_time = 0;
+ pt->next = NULL;
+ return pt;
+}
+
+/* poor man's linked list */
+static pr_track_t *list_last(pr_track_t *list)
+{
+ pr_track_t *tail = list;
+ if (!tail)
+ return NULL;
+ while (tail->next) {
+ tail = tail->next;
+ }
+ return tail;
+}
+
+static pr_track_t *list_add(pr_track_t *list, pr_track_t *element)
+{
+ pr_track_t *tail = list_last(list);
+ if (!tail)
+ return element;
+ tail->next = element;
+ return list;
+}
+
+static void list_free(pr_track_t *list)
+{
+ if (!list)
+ return;
+ list_free(list->next);
+ free(list);
+}
+
+#ifdef DEBUG_PR_TRACK
+static void dump_pr_track(pr_track_t **track_pr)
+{
+ int cyl;
+ pr_track_t *list;
+
+ for (cyl = 0; cyl < MAX_CYLINDERS; cyl++) {
+ list = track_pr[cyl];
+ while (list) {
+ printf("cyl%d: start %d end %d t_start %d t_end %d pt %d\n", cyl,
+ list->start, list->end, list->t_start, list->t_end, list->pressure_time);
+ list = list->next;
+ }
+ }
+}
+#endif
+
+/*
+ * This looks at the pressures for one cylinder, and
+ * calculates any missing beginning/end pressures for
+ * each segment by taking the over-all SAC-rate into
+ * account for that cylinder.
+ *
+ * NOTE! Many segments have full pressure information
+ * (both beginning and ending pressure). But if we have
+ * switched away from a cylinder, we will have the
+ * beginning pressure for the first segment with a
+ * missing end pressure. We may then have one or more
+ * segments without beginning or end pressures, until
+ * we finally have a segment with an end pressure.
+ *
+ * We want to spread out the pressure over these missing
+ * segments according to how big of a time_pressure area
+ * they have.
+ */
+static void fill_missing_segment_pressures(pr_track_t *list, enum interpolation_strategy strategy)
+{
+ double magic;
+
+ while (list) {
+ int start = list->start, end;
+ pr_track_t *tmp = list;
+ int pt_sum = 0, pt = 0;
+
+ for (;;) {
+ pt_sum += tmp->pressure_time;
+ end = tmp->end;
+ if (end)
+ break;
+ end = start;
+ if (!tmp->next)
+ break;
+ tmp = tmp->next;
+ }
+
+ if (!start)
+ start = end;
+
+ /*
+ * Now 'start' and 'end' contain the pressure values
+ * for the set of segments described by 'list'..'tmp'.
+ * pt_sum is the sum of all the pressure-times of the
+ * segments.
+ *
+ * Now dole out the pressures relative to pressure-time.
+ */
+ list->start = start;
+ tmp->end = end;
+ switch (strategy) {
+ case SAC:
+ for (;;) {
+ int pressure;
+ pt += list->pressure_time;
+ pressure = start;
+ if (pt_sum)
+ pressure -= (start - end) * (double)pt / pt_sum;
+ list->end = pressure;
+ if (list == tmp)
+ break;
+ list = list->next;
+ list->start = pressure;
+ }
+ break;
+ case TIME:
+ if (list->t_end && (tmp->t_start - tmp->t_end)) {
+ magic = (list->t_start - tmp->t_end) / (tmp->t_start - tmp->t_end);
+ list->end = rint(start - (start - end) * magic);
+ } else {
+ list->end = start;
+ }
+ break;
+ case CONSTANT:
+ list->end = start;
+ }
+
+ /* Ok, we've done that set of segments */
+ list = list->next;
+ }
+}
+
+#ifdef DEBUG_PR_INTERPOLATE
+void dump_pr_interpolate(int i, pr_interpolate_t interpolate_pr)
+{
+ printf("Interpolate for entry %d: start %d - end %d - pt %d - acc_pt %d\n", i,
+ interpolate_pr.start, interpolate_pr.end, interpolate_pr.pressure_time, interpolate_pr.acc_pressure_time);
+}
+#endif
+
+
+static struct pr_interpolate_struct get_pr_interpolate_data(pr_track_t *segment, struct plot_info *pi, int cur)
+{ // cur = index to pi->entry corresponding to t_end of segment;
+ struct pr_interpolate_struct interpolate;
+ int i;
+ struct plot_data *entry;
+
+ interpolate.start = segment->start;
+ interpolate.end = segment->end;
+ interpolate.acc_pressure_time = 0;
+ interpolate.pressure_time = 0;
+
+ for (i = 0; i < pi->nr; i++) {
+ entry = pi->entry + i;
+
+ if (entry->sec < segment->t_start)
+ continue;
+ interpolate.pressure_time += entry->pressure_time;
+ if (entry->sec >= segment->t_end)
+ break;
+ if (i <= cur)
+ interpolate.acc_pressure_time += entry->pressure_time;
+ }
+ return interpolate;
+}
+
+static void fill_missing_tank_pressures(struct dive *dive, struct plot_info *pi, pr_track_t **track_pr, bool o2_flag)
+{
+ int cyl, i;
+ struct plot_data *entry;
+ pr_interpolate_t interpolate = { 0, 0, 0, 0 };
+ pr_track_t *last_segment = NULL;
+ int cur_pr[MAX_CYLINDERS]; // cur_pr[MAX_CYLINDERS] is the CCR diluent cylinder
+
+ for (cyl = 0; cyl < MAX_CYLINDERS; cyl++) {
+ enum interpolation_strategy strategy;
+ if (!track_pr[cyl]) {
+ /* no segment where this cylinder is used */
+ cur_pr[cyl] = -1;
+ continue;
+ }
+ if (dive->cylinder[cyl].cylinder_use == OC_GAS)
+ strategy = SAC;
+ else
+ strategy = TIME;
+ fill_missing_segment_pressures(track_pr[cyl], strategy); // Interpolate the missing tank pressure values ..
+ cur_pr[cyl] = track_pr[cyl]->start; // in the pr_track_t lists of structures
+ } // and keep the starting pressure for each cylinder.
+
+#ifdef DEBUG_PR_TRACK
+ /* another great debugging tool */
+ dump_pr_track(track_pr);
+#endif
+
+ /* Transfer interpolated cylinder pressures from pr_track strucktures to plotdata
+ * Go down the list of tank pressures in plot_info. Align them with the start &
+ * end times of each profile segment represented by a pr_track_t structure. Get
+ * the accumulated pressure_depths from the pr_track_t structures and then
+ * interpolate the pressure where these do not exist in the plot_info pressure
+ * variables. Pressure values are transferred from the pr_track_t structures
+ * to the plot_info structure, allowing us to plot the tank pressure.
+ *
+ * The first two pi structures are "fillers", but in case we don't have a sample
+ * at time 0 we need to process the second of them here, therefore i=1 */
+ for (i = 1; i < pi->nr; i++) { // For each point on the profile:
+ double magic;
+ pr_track_t *segment;
+ int pressure;
+ int *save_pressure, *save_interpolated;
+
+ entry = pi->entry + i;
+
+ if (o2_flag) {
+ // Find the cylinder index (cyl) and pressure
+ cyl = dive->oxygen_cylinder_index;
+ if (cyl < 0)
+ return; // Can we do this?!?
+ pressure = O2CYLINDER_PRESSURE(entry);
+ save_pressure = &(entry->o2cylinderpressure[SENSOR_PR]);
+ save_interpolated = &(entry->o2cylinderpressure[INTERPOLATED_PR]);
+ } else {
+ pressure = SENSOR_PRESSURE(entry);
+ save_pressure = &(entry->pressure[SENSOR_PR]);
+ save_interpolated = &(entry->pressure[INTERPOLATED_PR]);
+ cyl = entry->cylinderindex;
+ }
+
+ if (pressure) { // If there is a valid pressure value,
+ last_segment = NULL; // get rid of interpolation data,
+ cur_pr[cyl] = pressure; // set current pressure
+ continue; // and skip to next point.
+ }
+ // If there is NO valid pressure value..
+ // Find the pressure segment corresponding to this entry..
+ segment = track_pr[cyl];
+ while (segment && segment->t_end < entry->sec) // Find the track_pr with end time..
+ segment = segment->next; // ..that matches the plot_info time (entry->sec)
+
+ if (!segment || !segment->pressure_time) { // No (or empty) segment?
+ *save_pressure = cur_pr[cyl]; // Just use our current pressure
+ continue; // and skip to next point.
+ }
+
+ // If there is a valid segment but no tank pressure ..
+ if (segment == last_segment) {
+ interpolate.acc_pressure_time += entry->pressure_time;
+ } else {
+ // Set up an interpolation structure
+ interpolate = get_pr_interpolate_data(segment, pi, i);
+ last_segment = segment;
+ }
+
+ if(dive->cylinder[cyl].cylinder_use == OC_GAS) {
+
+ /* if this segment has pressure_time, then calculate a new interpolated pressure */
+ if (interpolate.pressure_time) {
+ /* Overall pressure change over total pressure-time for this segment*/
+ magic = (interpolate.end - interpolate.start) / (double)interpolate.pressure_time;
+
+ /* Use that overall pressure change to update the current pressure */
+ cur_pr[cyl] = rint(interpolate.start + magic * interpolate.acc_pressure_time);
+ }
+ } else {
+ magic = (interpolate.end - interpolate.start) / (segment->t_end - segment->t_start);
+ cur_pr[cyl] = rint(segment->start + magic * (entry->sec - segment->t_start));
+ }
+ *save_interpolated = cur_pr[cyl]; // and store the interpolated data in plot_info
+ }
+}
+
+
+/*
+ * What's the pressure-time between two plot data entries?
+ * We're calculating the integral of pressure over time by
+ * adding these up.
+ *
+ * The units won't matter as long as everybody agrees about
+ * them, since they'll cancel out - we use this to calculate
+ * a constant SAC-rate-equivalent, but we only use it to
+ * scale pressures, so it ends up being a unitless scaling
+ * factor.
+ */
+static inline int calc_pressure_time(struct dive *dive, struct plot_data *a, struct plot_data *b)
+{
+ int time = b->sec - a->sec;
+ int depth = (a->depth + b->depth) / 2;
+
+ if (depth <= SURFACE_THRESHOLD)
+ return 0;
+
+ return depth_to_mbar(depth, dive) * time;
+}
+
+#ifdef PRINT_PRESSURES_DEBUG
+// A CCR debugging tool that prints the gas pressures in cylinder 0 and in the diluent cylinder, used in populate_pressure_information():
+static void debug_print_pressures(struct plot_info *pi)
+{
+ int i;
+ for (i = 0; i < pi->nr; i++) {
+ struct plot_data *entry = pi->entry + i;
+ printf("%5d |%9d | %9d || %9d | %9d |\n", i, SENSOR_PRESSURE(entry), INTERPOLATED_PRESSURE(entry), DILUENT_PRESSURE(entry), INTERPOLATED_DILUENT_PRESSURE(entry));
+ }
+}
+#endif
+
+/* This function goes through the list of tank pressures, either SENSOR_PRESSURE(entry) or O2CYLINDER_PRESSURE(entry),
+ * of structure plot_info for the dive profile where each item in the list corresponds to one point (node) of the
+ * profile. It finds values for which there are no tank pressures (pressure==0). For each missing item (node) of
+ * tank pressure it creates a pr_track_alloc structure that represents a segment on the dive profile and that
+ * contains tank pressures. There is a linked list of pr_track_alloc structures for each cylinder. These pr_track_alloc
+ * structures ultimately allow for filling the missing tank pressure values on the dive profile using the depth_pressure
+ * of the dive. To do this, it calculates the summed pressure-time value for the duration of the dive and stores these
+ * in the pr_track_alloc structures. If diluent_flag = 1, then DILUENT_PRESSURE(entry) is used instead of SENSOR_PRESSURE.
+ * This function is called by create_plot_info_new() in profile.c
+ */
+void populate_pressure_information(struct dive *dive, struct divecomputer *dc, struct plot_info *pi, int o2_flag)
+{
+ (void) dc;
+ int i, cylinderid, cylinderindex = -1;
+ pr_track_t *track_pr[MAX_CYLINDERS] = { NULL, };
+ pr_track_t *current = NULL;
+ bool missing_pr = false;
+ bool found_any_pr_data = false;
+
+ /* if we have no pressure data whatsoever, this is pointless, so let's just return */
+ for (i = 0; i < MAX_CYLINDERS; i++) {
+ if (dive->cylinder[i].start.mbar || dive->cylinder[i].sample_start.mbar ||
+ dive->cylinder[i].end.mbar || dive->cylinder[i].sample_end.mbar) {
+ found_any_pr_data = true;
+ break;
+ }
+ }
+ if (!found_any_pr_data)
+ return;
+
+ for (i = 0; i < pi->nr; i++) {
+ struct plot_data *entry = pi->entry + i;
+ unsigned pressure;
+ if (o2_flag) { // if this is a diluent cylinder:
+ pressure = O2CYLINDER_PRESSURE(entry);
+ cylinderid = dive->oxygen_cylinder_index;
+ if (cylinderid < 0)
+ goto GIVE_UP;
+ } else {
+ pressure = SENSOR_PRESSURE(entry);
+ cylinderid = entry->cylinderindex;
+ }
+ /* If track_pr structure already exists, then update it: */
+ /* discrete integration of pressure over time to get the SAC rate equivalent */
+ if (current) {
+ entry->pressure_time = calc_pressure_time(dive, entry - 1, entry);
+ current->pressure_time += entry->pressure_time;
+ current->t_end = entry->sec;
+ }
+
+ /* If 1st record or different cylinder: Create a new track_pr structure: */
+ /* track the segments per cylinder and their pressure/time integral */
+ if (cylinderid != cylinderindex) {
+ if (o2_flag) // For CCR dives:
+ cylinderindex = dive->oxygen_cylinder_index; // indicate o2 cylinder
+ else
+ cylinderindex = entry->cylinderindex;
+ current = pr_track_alloc(pressure, entry->sec);
+ track_pr[cylinderindex] = list_add(track_pr[cylinderindex], current);
+ continue;
+ }
+
+ if (!pressure) {
+ missing_pr = 1;
+ continue;
+ }
+ if (current)
+ current->end = pressure;
+
+ /* Was it continuous? */
+ if ((o2_flag) && (O2CYLINDER_PRESSURE(entry - 1))) // in the case of CCR o2 pressure
+ continue;
+ else if (SENSOR_PRESSURE(entry - 1)) // for all other cylinders
+ continue;
+
+ /* transmitter stopped transmitting cylinder pressure data */
+ current = pr_track_alloc(pressure, entry->sec);
+ if (cylinderindex >= 0)
+ track_pr[cylinderindex] = list_add(track_pr[cylinderindex], current);
+ }
+
+ if (missing_pr) {
+ fill_missing_tank_pressures(dive, pi, track_pr, o2_flag);
+ }
+
+#ifdef PRINT_PRESSURES_DEBUG
+ debug_print_pressures(pi);
+#endif
+
+GIVE_UP:
+ for (i = 0; i < MAX_CYLINDERS; i++)
+ list_free(track_pr[i]);
+}