summaryrefslogtreecommitdiffstats
path: root/dive.h
blob: 1386a3bf8d8b7a999e08bcf4fcb6b99faeae47e5 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
#ifndef DIVE_H
#define DIVE_H

#include <stdlib.h>
#include <time.h>

/*
 * Some silly typedefs to make our units very explicit.
 *
 * Also, the units are chosen so that values can be expressible as
 * integers, so that we never have FP rounding issues. And they
 * are small enough that converting to/from imperial units doesn't
 * really matter.
 *
 * We also strive to make '0' a meaningless number saying "not
 * initialized", since many values are things that may not have
 * been reported (eg cylinder pressure or temperature from dive
 * computers that don't support them). But sometimes -1 is an even
 * more explicit way of saying "not there".
 *
 * Thus "millibar" for pressure, for example, or "millikelvin" for
 * temperatures. Doing temperatures in celsius or fahrenheit would
 * make for loss of precision when converting from one to the other,
 * and using millikelvin is SI-like but also means that a temperature
 * of '0' is clearly just a missing temperature or cylinder pressure.
 *
 * Also strive to use units that can not possibly be mistaken for a
 * valid value in a "normal" system without conversion. If the max
 * depth of a dive is '20000', you probably didn't convert from mm on
 * output, or if the max depth gets reported as "0.2ft" it was either
 * a really boring dive, or there was some missing input conversion,
 * and a 60-ft dive got recorded as 60mm.
 *
 * Doing these as "structs containing value" means that we always
 * have to explicitly write out those units in order to get at the
 * actual value. So there is hopefully little fear of using a value
 * in millikelvin as Fahrenheit by mistake.
 *
 * We don't actually use these all yet, so maybe they'll change, but
 * I made a number of types as guidelines.
 */
typedef struct {
	int seconds;
} duration_t;

typedef struct {
	int mm;
} depth_t;

typedef struct {
	int mbar;
} pressure_t;

typedef struct {
	int mkelvin;
} temperature_t;

typedef struct {
	int mliter;
} volume_t;

typedef struct {
	int permille;
} fraction_t;

typedef struct {
	int grams;
} weight_t;

typedef struct {
	fraction_t o2;
	fraction_t he;
} gasmix_t;

typedef struct {
	volume_t size;
	pressure_t workingpressure;
	const char *description;	/* "LP85", "AL72", "AL80", "HP100+" or whatever */
} cylinder_type_t;

typedef struct {
	cylinder_type_t type;
	gasmix_t gasmix;
} cylinder_t;

static inline int to_feet(depth_t depth)
{
	return depth.mm * 0.00328084 + 0.5;
}

static inline int to_C(temperature_t temp)
{
	if (!temp.mkelvin)
		return 0;
	return (temp.mkelvin - 273150) / 1000;
}

static inline int to_PSI(pressure_t pressure)
{
	return pressure.mbar * 0.0145037738 + 0.5;
}

struct sample {
	duration_t time;
	depth_t depth;
	temperature_t temperature;
	pressure_t cylinderpressure;
	int cylinderindex;
};

#define MAX_CYLINDERS (4)

struct dive {
	time_t when;
	char *location;
	char *notes;
	depth_t maxdepth, meandepth;
	duration_t duration, surfacetime;
	depth_t visibility;
	temperature_t airtemp, watertemp;
	pressure_t beginning_pressure, end_pressure;
	cylinder_t cylinder[MAX_CYLINDERS];
	int samples;
	struct sample sample[];
};

extern int verbose;

struct dive_table {
	int nr, allocated;
	struct dive **dives;
};

extern struct dive_table dive_table;

static inline struct dive *get_dive(unsigned int nr)
{
	if (nr >= dive_table.nr)
		return NULL;
	return dive_table.dives[nr];
}

extern void parse_xml_init(void);
extern void parse_xml_file(const char *filename);

extern void flush_dive_info_changes(void);
extern void save_dives(const char *filename);

static inline unsigned int dive_size(int samples)
{
	return sizeof(struct dive) + samples*sizeof(struct sample);
}

extern struct dive *fixup_dive(struct dive *dive);
extern struct dive *try_to_merge(struct dive *a, struct dive *b);

#endif /* DIVE_H */