CCR code: Split profile.c into two files, with gas caluclations separate.

This patch implements a separation of the code for gas pressure
calculations from the rest of the code in profile.c. The latter
file is now split into: profile.c and gaspressures.c. The
details of the transferred functions is given at the top of
gaspressures.c. The following chnages were made:
1) dive.h: The function types of calculate_depth_to_mbar
   and depth_to_mbar were made non-static in order to make them
   available within gaspressures.c.
2) profile.c: Prototypes for the functions in gaspressures.c
   were inserted at the top of profile. Ten functions were
   transferred from profile.c to gaspressures.c
3) gaspressures.c as well as a short header, gaspressures.h
   were created.

For the gas pressure calculations for CCR dives, gaspressures.c
forms the immediate basis for further code development.

Signed-off-by: Willem Ferguson <willemferguson@zoology.up.ac.za>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

1 files changed, 6 insertions, 341 deletions

diff --git a/profile.c b/profile.c
index 0a4d9e19a..044da0eca 100644
--- a/profile.c
+++ b/profile.c
@@ -10,6 +10,7 @@
 #include "divelist.h"
 
 #include "profile.h"
+#include "gaspressures.h"
 #include "deco.h"
 #include "libdivecomputer/parser.h"
 #include "libdivecomputer/version.h"
@@ -18,9 +19,13 @@
 int selected_dive = -1; /* careful: 0 is a valid value */
 unsigned int dc_number = 0;
 
-
 static struct plot_data *last_pi_entry_new = NULL;
 
+void fill_missing_segment_pressures(pr_track_t*);
+struct pr_interpolate_struct get_pr_interpolate_data(pr_track_t*, struct plot_info*, int);
+void fill_missing_tank_pressures(struct dive*, struct plot_info*, pr_track_t**);
+void populate_pressure_information(struct dive*, struct divecomputer*, struct plot_info*);
+
 #ifdef DEBUG_PI
 /* debugging tool - not normally used */
 static void dump_pi(struct plot_info *pi)
@@ -284,295 +289,6 @@ struct plot_info *analyze_plot_info(struct plot_info *pi)
 	return pi;
 }
 
-/*
- * simple structure to track the beginning and end tank pressure as
- * well as the integral of depth over time spent while we have no
- * pressure reading from the tank */
-typedef struct pr_track_struct pr_track_t;
-struct pr_track_struct {
-	int start;
-	int end;
-	int t_start;
-	int t_end;
-	int pressure_time;
-	pr_track_t *next;
-};
-
-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
-
-typedef struct pr_interpolate_struct pr_interpolate_t;
-struct pr_interpolate_struct {
-	int start;
-	int end;
-	int pressure_time;
-	int acc_pressure_time;
-};
-
-#ifdef DEBUG_PR_INTERPOLATE
-static 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
-
-/*
- * 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)
-{
-	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;
-		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;
-		}
-
-		/* Ok, we've done that set of segments */
-		list = list->next;
-	}
-}
-
-/*
- * 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 pressure_time(struct dive *dive, struct divecomputer *dc, 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;
-}
-
-static struct pr_interpolate_struct get_pr_interpolate_data(pr_track_t *segment, struct plot_info *pi, int cur)
-{
-	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;
-		if (entry->sec >= segment->t_end) {
-			interpolate.pressure_time += entry->pressure_time;
-			break;
-		}
-		if (entry->sec == segment->t_start) {
-			interpolate.acc_pressure_time = 0;
-			interpolate.pressure_time = 0;
-			if (SENSOR_PRESSURE(entry))
-				interpolate.start = SENSOR_PRESSURE(entry);
-			continue;
-		}
-		if (i < cur) {
-			if (SENSOR_PRESSURE(entry)) {
-				interpolate.start = SENSOR_PRESSURE(entry);
-				interpolate.acc_pressure_time = 0;
-				interpolate.pressure_time = 0;
-			} else {
-				interpolate.acc_pressure_time += entry->pressure_time;
-				interpolate.pressure_time += entry->pressure_time;
-			}
-			continue;
-		}
-		if (i == cur) {
-			interpolate.acc_pressure_time += entry->pressure_time;
-			interpolate.pressure_time += entry->pressure_time;
-			continue;
-		}
-		interpolate.pressure_time += entry->pressure_time;
-		if (SENSOR_PRESSURE(entry)) {
-			interpolate.end = SENSOR_PRESSURE(entry);
-			break;
-		}
-	}
-	return interpolate;
-}
-
-static void fill_missing_tank_pressures(struct dive *dive, struct plot_info *pi, pr_track_t **track_pr)
-{
-	int cyl, i;
-	struct plot_data *entry;
-	int cur_pr[MAX_CYLINDERS];
-
-#ifdef DEBUG_PR_TRACK
-	/* another great debugging tool */
-	dump_pr_track(track_pr);
-#endif
-	for (cyl = 0; cyl < MAX_CYLINDERS; cyl++) {
-		if (!track_pr[cyl]) {
-			/* no segment where this cylinder is used */
-			cur_pr[cyl] = -1;
-			continue;
-		}
-		fill_missing_segment_pressures(track_pr[cyl]);
-		cur_pr[cyl] = track_pr[cyl]->start;
-	}
-
-	/* The first two are "fillers", but in case we don't have a sample
-	 * at time 0 we need to process the second of them here */
-	for (i = 1; i < pi->nr; i++) {
-		double magic;
-		pr_track_t *segment;
-		pr_interpolate_t interpolate;
-
-		entry = pi->entry + i;
-		cyl = entry->cylinderindex;
-
-		if (SENSOR_PRESSURE(entry)) {
-			cur_pr[cyl] = SENSOR_PRESSURE(entry);
-			continue;
-		}
-
-		/* Find the right pressure segment for this entry.. */
-		segment = track_pr[cyl];
-		while (segment && segment->t_end < entry->sec)
-			segment = segment->next;
-
-		/* No (or empty) segment? Just use our current pressure */
-		if (!segment || !segment->pressure_time) {
-			SENSOR_PRESSURE(entry) = cur_pr[cyl];
-			continue;
-		}
-
-		interpolate = get_pr_interpolate_data(segment, pi, i);
-#ifdef DEBUG_PR_INTERPOLATE
-		dump_pr_interpolate(i, interpolate);
-#endif
-		/* if this segment has pressure time, 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);
-		}
-		INTERPOLATED_PRESSURE(entry) = cur_pr[cyl];
-	}
-}
-
 int get_cylinder_index(struct dive *dive, struct event *ev)
 {
 	int i;
@@ -955,57 +671,6 @@ static void setup_gas_sensor_pressure(struct dive *dive, struct divecomputer *dc
 	} while ((secondary = secondary->next) != NULL);
 }
 
-static void populate_pressure_information(struct dive *dive, struct divecomputer *dc, struct plot_info *pi)
-{
-	int i, cylinderindex;
-	pr_track_t *track_pr[MAX_CYLINDERS] = { NULL, };
-	pr_track_t *current;
-	bool missing_pr = false;
-
-	cylinderindex = -1;
-	current = NULL;
-	for (i = 0; i < pi->nr; i++) {
-		struct plot_data *entry = pi->entry + i;
-		int pressure = SENSOR_PRESSURE(entry);
-
-		/* discrete integration of pressure over time to get the SAC rate equivalent */
-		if (current) {
-			entry->pressure_time = pressure_time(dive, dc, entry - 1, entry);
-			current->pressure_time += entry->pressure_time;
-			current->t_end = entry->sec;
-		}
-
-		/* track the segments per cylinder and their pressure/time integral */
-		if (entry->cylinderindex != cylinderindex) {
-			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;
-		}
-
-		current->end = pressure;
-
-		/* Was it continuous? */
-		if (SENSOR_PRESSURE(entry - 1))
-			continue;
-
-		/* transmitter changed its working status */
-		current = pr_track_alloc(pressure, entry->sec);
-		track_pr[cylinderindex] = list_add(track_pr[cylinderindex], current);
-	}
-
-	if (missing_pr) {
-		fill_missing_tank_pressures(dive, pi, track_pr);
-	}
-	for (i = 0; i < MAX_CYLINDERS; i++)
-		list_free(track_pr[i]);
-}
-
 /* calculate DECO STOP / TTS / NDL */
 static void calculate_ndl_tts(double tissue_tolerance, struct plot_data *entry, struct dive *dive, double surface_pressure)
 {