subsurface/core/divecomputer.cpp
Berthold Stoeger f120fecccb core: use std::vector<> to store divecomputer samples
This is a hairy one, because the sample code is rather tricky.

There was a pattern of looping through pairs of adjacent samples,
for interpolation purposes. Add an range adapter to generalize
such loops.

Removes the finish_sample() function: The code would call
prepare_sample() to start parsing of samples and then
finish_sample() to actuall add it. I.e. a kind of commit().

Since, with one exception, all users of prepare_sample()
called finish_sample() in all code paths, we might just add
the sample in the first place. The exception was sample_end()
in parse.cpp. This brings a small change: samples are now
added, even if they could only be parsed partially. I doubt
that this makes any difference, since it will only happen
for broken divelogs anyway.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
2024-08-13 19:28:30 +02:00

493 lines
12 KiB
C++

// SPDX-License-Identifier: GPL-2.0
#include "divecomputer.h"
#include "event.h"
#include "extradata.h"
#include "pref.h"
#include "sample.h"
#include "structured_list.h"
#include "subsurface-string.h"
#include <string.h>
#include <stdlib.h>
divecomputer::divecomputer()
{
}
divecomputer::~divecomputer()
{
free_dc_contents(this);
}
divecomputer::divecomputer(divecomputer &&) = default;
divecomputer &divecomputer::operator=(const divecomputer &) = default;
/*
* Good fake dive profiles are hard.
*
* "depthtime" is the integral of the dive depth over
* time ("area" of the dive profile). We want that
* area to match the average depth (avg_d*max_t).
*
* To do that, we generate a 6-point profile:
*
* (0, 0)
* (t1, max_d)
* (t2, max_d)
* (t3, d)
* (t4, d)
* (max_t, 0)
*
* with the same ascent/descent rates between the
* different depths.
*
* NOTE: avg_d, max_d and max_t are given constants.
* The rest we can/should play around with to get a
* good-looking profile.
*
* That six-point profile gives a total area of:
*
* (max_d*max_t) - (max_d*t1) - (max_d-d)*(t4-t3)
*
* And the "same ascent/descent rates" requirement
* gives us (time per depth must be same):
*
* t1 / max_d = (t3-t2) / (max_d-d)
* t1 / max_d = (max_t-t4) / d
*
* We also obviously require:
*
* 0 <= t1 <= t2 <= t3 <= t4 <= max_t
*
* Let us call 'd_frac = d / max_d', and we get:
*
* Total area must match average depth-time:
*
* (max_d*max_t) - (max_d*t1) - (max_d-d)*(t4-t3) = avg_d*max_t
* max_d*(max_t-t1-(1-d_frac)*(t4-t3)) = avg_d*max_t
* max_t-t1-(1-d_frac)*(t4-t3) = avg_d*max_t/max_d
* t1+(1-d_frac)*(t4-t3) = max_t*(1-avg_d/max_d)
*
* and descent slope must match ascent slopes:
*
* t1 / max_d = (t3-t2) / (max_d*(1-d_frac))
* t1 = (t3-t2)/(1-d_frac)
*
* and
*
* t1 / max_d = (max_t-t4) / (max_d*d_frac)
* t1 = (max_t-t4)/d_frac
*
* In general, we have more free variables than we have constraints,
* but we can aim for certain basics, like a good ascent slope.
*/
static int fill_samples(std::vector<sample> &s, int max_d, int avg_d, int max_t, double slope, double d_frac)
{
double t_frac = max_t * (1 - avg_d / (double)max_d);
int t1 = lrint(max_d / slope);
int t4 = lrint(max_t - t1 * d_frac);
int t3 = lrint(t4 - (t_frac - t1) / (1 - d_frac));
int t2 = lrint(t3 - t1 * (1 - d_frac));
if (t1 < 0 || t1 > t2 || t2 > t3 || t3 > t4 || t4 > max_t)
return 0;
s[1].time.seconds = t1;
s[1].depth.mm = max_d;
s[2].time.seconds = t2;
s[2].depth.mm = max_d;
s[3].time.seconds = t3;
s[3].depth.mm = lrint(max_d * d_frac);
s[4].time.seconds = t4;
s[4].depth.mm = lrint(max_d * d_frac);
return 1;
}
/* we have no average depth; instead of making up a random average depth
* we should assume either a PADI rectangular profile (for short and/or
* shallow dives) or more reasonably a six point profile with a 3 minute
* safety stop at 5m */
static void fill_samples_no_avg(std::vector<sample> &s, int max_d, int max_t, double slope)
{
// shallow or short dives are just trapecoids based on the given slope
if (max_d < 10000 || max_t < 600) {
s[1].time.seconds = lrint(max_d / slope);
s[1].depth.mm = max_d;
s[2].time.seconds = max_t - lrint(max_d / slope);
s[2].depth.mm = max_d;
} else {
s[1].time.seconds = lrint(max_d / slope);
s[1].depth.mm = max_d;
s[2].time.seconds = max_t - lrint(max_d / slope) - 180;
s[2].depth.mm = max_d;
s[3].time.seconds = max_t - lrint(5000 / slope) - 180;
s[3].depth.mm = 5000;
s[4].time.seconds = max_t - lrint(5000 / slope);
s[4].depth.mm = 5000;
}
}
void fake_dc(struct divecomputer *dc)
{
/* The dive has no samples, so create a few fake ones */
int max_t = dc->duration.seconds;
int max_d = dc->maxdepth.mm;
int avg_d = dc->meandepth.mm;
if (!max_t || !max_d) {
dc->samples.clear();
return;
}
std::vector<struct sample> &fake = dc->samples;
fake.resize(6);
fake[5].time.seconds = max_t;
for (int i = 0; i < 6; i++) {
fake[i].bearing.degrees = -1;
fake[i].ndl.seconds = -1;
}
/* Set last manually entered time to the total dive length */
dc->last_manual_time = dc->duration;
/*
* We want to fake the profile so that the average
* depth ends up correct. However, in the absence of
* a reasonable average, let's just make something
* up. Note that 'avg_d == max_d' is _not_ a reasonable
* average.
* We explicitly treat avg_d == 0 differently */
if (avg_d == 0) {
/* we try for a sane slope, but bow to the insanity of
* the user supplied data */
fill_samples_no_avg(fake, max_d, max_t, std::max(2.0 * max_d / max_t, (double)prefs.ascratelast6m));
if (fake[3].time.seconds == 0) { // just a 4 point profile
dc->samples.resize(4);
fake[3].time.seconds = max_t;
}
return;
}
if (avg_d < max_d / 10 || avg_d >= max_d) {
avg_d = (max_d + 10000) / 3;
if (avg_d > max_d)
avg_d = max_d * 2 / 3;
}
if (!avg_d)
avg_d = 1;
/*
* Ok, first we try a basic profile with a specific ascent
* rate (5 meters per minute) and d_frac (1/3).
*/
if (fill_samples(fake, max_d, avg_d, max_t, (double)prefs.ascratelast6m, 0.33))
return;
/*
* Ok, assume that didn't work because we cannot make the
* average come out right because it was a quick deep dive
* followed by a much shallower region
*/
if (fill_samples(fake, max_d, avg_d, max_t, 10000.0 / 60, 0.10))
return;
/*
* Uhhuh. That didn't work. We'd need to find a good combination that
* satisfies our constraints. Currently, we don't, we just give insane
* slopes.
*/
if (fill_samples(fake, max_d, avg_d, max_t, 10000.0, 0.01))
return;
/* Even that didn't work? Give up, there's something wrong */
}
/* Find the divemode at time 'time' (in seconds) into the dive. Sequentially step through the divemode-change events,
* saving the dive mode for each event. When the events occur AFTER 'time' seconds, the last stored divemode
* is returned. This function is self-tracking, relying on setting the event pointer 'evp' so that, in each iteration
* that calls this function, the search does not have to begin at the first event of the dive */
enum divemode_t get_current_divemode(const struct divecomputer *dc, int time, const struct event **evp, enum divemode_t *divemode)
{
const struct event *ev = *evp;
if (dc) {
if (*divemode == UNDEF_COMP_TYPE) {
*divemode = dc->divemode;
ev = get_next_event(dc->events, "modechange");
}
} else {
ev = NULL;
}
while (ev && ev->time.seconds < time) {
*divemode = (enum divemode_t) ev->value;
ev = get_next_event(ev->next, "modechange");
}
*evp = ev;
return *divemode;
}
/* helper function to make it easier to work with our structures
* we don't interpolate here, just use the value from the last sample up to that time */
int get_depth_at_time(const struct divecomputer *dc, unsigned int time)
{
int depth = 0;
if (dc) {
for (const auto &sample: dc->samples) {
if (sample.time.seconds > (int)time)
break;
depth = sample.depth.mm;
}
}
return depth;
}
static void free_dc(struct divecomputer *dc)
{
delete dc;
}
/* The first divecomputer is embedded in the dive structure. Ignore it.
* For all remainding dcs in the list, free data and structures. */
void free_dive_dcs(struct divecomputer *dc)
{
STRUCTURED_LIST_FREE(struct divecomputer, dc->next, free_dc);
}
struct sample *prepare_sample(struct divecomputer *dc)
{
if (dc) {
dc->samples.emplace_back();
auto &sample = dc->samples.back();
// Copy the sensor numbers - but not the pressure values
// from the previous sample if any.
if (dc->samples.size() >= 2) {
auto &prev = dc->samples[dc->samples.size() - 2];
for (int idx = 0; idx < MAX_SENSORS; idx++)
sample.sensor[idx] = prev.sensor[idx];
}
// Init some values with -1
sample.bearing.degrees = -1;
sample.ndl.seconds = -1;
return &sample;
}
return NULL;
}
struct sample *add_sample(const struct sample *sample, int time, struct divecomputer *dc)
{
struct sample *p = prepare_sample(dc);
if (p) {
*p = *sample;
p->time.seconds = time;
}
return p;
}
/*
* Calculate how long we were actually under water, and the average
* depth while under water.
*
* This ignores any surface time in the middle of the dive.
*/
void fixup_dc_duration(struct divecomputer *dc)
{
int duration = 0;
int lasttime = 0, lastdepth = 0, depthtime = 0;
for (const auto &sample: dc->samples) {
int time = sample.time.seconds;
int depth = sample.depth.mm;
/* We ignore segments at the surface */
if (depth > SURFACE_THRESHOLD || lastdepth > SURFACE_THRESHOLD) {
duration += time - lasttime;
depthtime += (time - lasttime) * (depth + lastdepth) / 2;
}
lastdepth = depth;
lasttime = time;
}
if (duration) {
dc->duration.seconds = duration;
dc->meandepth.mm = (depthtime + duration / 2) / duration;
}
}
/*
* What do the dive computers say the water temperature is?
* (not in the samples, but as dc property for dcs that support that)
*/
unsigned int dc_watertemp(const struct divecomputer *dc)
{
int sum = 0, nr = 0;
do {
if (dc->watertemp.mkelvin) {
sum += dc->watertemp.mkelvin;
nr++;
}
} while ((dc = dc->next) != NULL);
if (!nr)
return 0;
return (sum + nr / 2) / nr;
}
/*
* What do the dive computers say the air temperature is?
*/
unsigned int dc_airtemp(const struct divecomputer *dc)
{
int sum = 0, nr = 0;
do {
if (dc->airtemp.mkelvin) {
sum += dc->airtemp.mkelvin;
nr++;
}
} while ((dc = dc->next) != NULL);
if (!nr)
return 0;
return (sum + nr / 2) / nr;
}
/* copies all events in this dive computer */
void copy_events(const struct divecomputer *s, struct divecomputer *d)
{
const struct event *ev;
struct event **pev;
if (!s || !d)
return;
ev = s->events;
pev = &d->events;
while (ev != NULL) {
struct event *new_ev = clone_event(ev);
*pev = new_ev;
pev = &new_ev->next;
ev = ev->next;
}
*pev = NULL;
}
void add_event_to_dc(struct divecomputer *dc, struct event *ev)
{
struct event **p;
p = &dc->events;
/* insert in the sorted list of events */
while (*p && (*p)->time.seconds <= ev->time.seconds)
p = &(*p)->next;
ev->next = *p;
*p = ev;
}
struct event *add_event(struct divecomputer *dc, unsigned int time, int type, int flags, int value, const std::string &name)
{
struct event *ev = create_event(time, type, flags, value, name);
if (!ev)
return NULL;
add_event_to_dc(dc, ev);
return ev;
}
/* Substitutes an event in a divecomputer for another. No reordering is performed! */
void swap_event(struct divecomputer *dc, struct event *from, struct event *to)
{
for (struct event **ep = &dc->events; *ep; ep = &(*ep)->next) {
if (*ep == from) {
to->next = from->next;
*ep = to;
from->next = NULL; // For good measure.
break;
}
}
}
/* Remove given event from dive computer. Does *not* free the event. */
void remove_event_from_dc(struct divecomputer *dc, struct event *event)
{
for (struct event **ep = &dc->events; *ep; ep = &(*ep)->next) {
if (*ep == event) {
*ep = event->next;
event->next = NULL; // For good measure.
break;
}
}
}
void add_extra_data(struct divecomputer *dc, const std::string &key, const std::string &value)
{
if (key == "Serial") {
dc->deviceid = calculate_string_hash(value.c_str());
dc->serial = value;
}
if (key == "FW Version")
dc->fw_version = value;
dc->extra_data.push_back(extra_data { key, value });
}
/*
* Match two dive computer entries against each other, and
* tell if it's the same dive. Return 0 if "don't know",
* positive for "same dive" and negative for "definitely
* not the same dive"
*/
int match_one_dc(const struct divecomputer *a, const struct divecomputer *b)
{
/* Not same model? Don't know if matching.. */
if (a->model.empty() || b->model.empty())
return 0;
if (strcasecmp(a->model.c_str(), b->model.c_str()))
return 0;
/* Different device ID's? Don't know */
if (a->deviceid != b->deviceid)
return 0;
/* Do we have dive IDs? */
if (!a->diveid || !b->diveid)
return 0;
/*
* If they have different dive ID's on the same
* dive computer, that's a definite "same or not"
*/
return a->diveid == b->diveid && a->when == b->when ? 1 : -1;
}
void free_dc_contents(struct divecomputer *dc)
{
free_events(dc->events);
}
static const char *planner_dc_name = "planned dive";
bool is_dc_planner(const struct divecomputer *dc)
{
return dc->model == planner_dc_name;
}
void make_planner_dc(struct divecomputer *dc)
{
dc->model = planner_dc_name;
}
const char *manual_dc_name = "manually added dive";
bool is_dc_manually_added_dive(const struct divecomputer *dc)
{
return dc->model == manual_dc_name;
}
void make_manually_added_dive_dc(struct divecomputer *dc)
{
dc->model = manual_dc_name;
}