Core: remove MAX_CYLINDERS restriction

Instead of using fixed size arrays, use a new cylinder_table structure.
The code copies the weightsystem code, but is significantly more complex
because cylinders are such an integral part of the core.

Two functions to access the cylinders were added:
get_cylinder() and get_or_create_cylinder()
The former does a simple array access and supposes that the cylinder
exists. The latter is used by the parser(s) and if a cylinder with
the given id does not exist, cylinders up to that id are generated.

One point will make C programmers cringe: the cylinder structure is
passed by value. This is due to the way the table-macros work. A
refactoring of the table macros is planned. It has to be noted that
the size of a cylinder_t is 64 bytes, i.e. 8 long words on a 64-bit
architecture, so passing on the stack is probably not even significantly
slower than passing as reference.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

1 files changed, 21 insertions, 4 deletions

diff --git a/core/equipment.h b/core/equipment.h
index beef30842..ce5683003 100644
--- a/core/equipment.h
+++ b/core/equipment.h
@@ -33,6 +33,17 @@ typedef struct
 	bool bestmix_he;
 } cylinder_t;
 
+/* Table of cylinders. Attention: this stores cylinders,
+ * *not* pointers to cylinders. This has two crucial consequences:
+ * 1) Pointers to cylinders are not stable. They may be
+ *    invalidated if the table is reallocated.
+ * 2) add_to_cylinder_table(), etc. take ownership of the
+ *    cylinder. Notably of the description string. */
+struct cylinder_table {
+	int nr, allocated;
+	cylinder_t *cylinders;
+};
+
 typedef struct
 {
 	weight_t weight;
@@ -51,7 +62,6 @@ struct weightsystem_table {
 	weightsystem_t *weightsystems;
 };
 
-#define MAX_CYLINDERS (20)
 #define MAX_TANK_INFO (100)
 #define MAX_WS_INFO (100)
 
@@ -59,16 +69,19 @@ extern int cylinderuse_from_text(const char *text);
 extern void copy_weights(const struct weightsystem_table *s, struct weightsystem_table *d);
 extern void copy_cylinder_types(const struct dive *s, struct dive *d);
 extern void add_cloned_weightsystem(struct weightsystem_table *t, weightsystem_t ws);
+extern void add_empty_cylinder(struct cylinder_table *t);
+extern void add_cloned_cylinder(struct cylinder_table *t, cylinder_t cyl);
+extern cylinder_t *get_cylinder(const struct dive *d, int idx);
+extern cylinder_t *get_or_create_cylinder(struct dive *d, int idx);
 extern void add_cylinder_description(const cylinder_type_t *);
 extern void add_weightsystem_description(const weightsystem_t *);
 extern bool same_weightsystem(weightsystem_t w1, weightsystem_t w2);
-extern bool cylinder_nodata(const cylinder_t *cyl);
-extern bool cylinder_none(const cylinder_t *cyl);
+extern bool same_cylinder(cylinder_t cyl1, cylinder_t cyl2);
 extern void remove_cylinder(struct dive *dive, int idx);
 extern void remove_weightsystem(struct dive *dive, int idx);
 extern void reset_cylinders(struct dive *dive, bool track_gas);
 extern int gas_volume(const cylinder_t *cyl, pressure_t p); /* Volume in mliter of a cylinder at pressure 'p' */
-extern int find_best_gasmix_match(struct gasmix mix, const cylinder_t array[]);
+extern int find_best_gasmix_match(struct gasmix mix, const struct cylinder_table *cylinders);
 #ifdef DEBUG_CYL
 extern void dump_cylinders(struct dive *dive, bool verbose);
 #endif
@@ -77,6 +90,10 @@ extern void dump_cylinders(struct dive *dive, bool verbose);
 extern void clear_weightsystem_table(struct weightsystem_table *);
 extern void add_to_weightsystem_table(struct weightsystem_table *, int idx, weightsystem_t ws);
 
+/* Cylinder table functions */
+extern void clear_cylinder_table(struct cylinder_table *);
+extern void add_to_cylinder_table(struct cylinder_table *, int idx, cylinder_t cyl);
+
 void get_gas_string(struct gasmix gasmix, char *text, int len);
 const char *gasname(struct gasmix gasmix);