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| author |  Berthold Stoeger <bstoeger@mail.tuwien.ac.at> | 2018-08-16 13:35:14 +0200 |
|---|---|---|
| committer |  Dirk Hohndel <dirk@hohndel.org> | 2018-08-23 05:16:38 -0700 |
| commit | f5b11daffd6f240268ce78d72c64be43670988ea (patch) | |
| tree | 99805cc176483e5f069a7920c11528e37cf0db8c /core/dive.h | |
| parent | b6187f73aad09adb0b70af8d77f1af1a34a338f8 (diff) | |
| download | subsurface-f5b11daffd6f240268ce78d72c64be43670988ea.tar.gz | |
Cleanup: return gasmix by value
Currently, get_gasmix_from_event() and get_gasmix() return pointers
to either static or to (possibly changing) dive data. This seems like
a dangerous practice and the returned data should be used immediately.
Instead, return the gasmix by value. This is in preparation of
const-ifying input parameters of a number of core functions, which
will ultimately let the merge() function take const-arguments in
preparation of undo of dive-merging.
On common 64-bit systems gasmix (two "int"s) is the size of a pointer
and can be returned in a register.
On 32-bit systems a pointer to the struct to be filled out will be
passed.
Since get_gasmix() now returns a value, the first invocation is
tested by a NULL-initialized "struct event *". Document this in
a comment.
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
Diffstat (limited to 'core/dive.h')
| -rw-r--r-- | core/dive.h | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/core/dive.h b/core/dive.h index 98ac06fdc..7e62262d9 100644 --- a/core/dive.h +++ b/core/dive.h @@ -585,7 +585,7 @@ extern void update_event_name(struct dive *d, struct event* event, const char *n extern void add_extra_data(struct divecomputer *dc, const char *key, const char *value); extern void per_cylinder_mean_depth(struct dive *dive, struct divecomputer *dc, int *mean, int *duration); extern int get_cylinder_index(struct dive *dive, struct event *ev); -extern struct gasmix *get_gasmix_from_event(struct dive *, struct event *ev); +extern struct gasmix get_gasmix_from_event(struct dive *, struct event *ev); extern int nr_cylinders(struct dive *dive); extern int nr_weightsystems(struct dive *dive); @@ -718,7 +718,11 @@ extern void printdecotable(struct decostop *table); extern struct event *get_next_event(struct event *event, const char *name); -extern struct gasmix *get_gasmix(struct dive *dive, struct divecomputer *dc, int time, struct event **evp, struct gasmix *gasmix); +/* Get gasmix at increasing timestamps. + * In "evp", pass a pointer to a "struct event *" which is NULL-initialized on first invocation. + * On subsequent calls, pass the same "evp" and the "gasmix" from previous calls. + */ +extern struct gasmix get_gasmix(struct dive *dive, struct divecomputer *dc, int time, struct event **evp, struct gasmix *gasmix); /* these structs holds the information that * describes the cylinders / weight systems. |