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
|
/*
* Copyright © 2024 Michael Smith <mikesmiffy128@gmail.com>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED “AS IS” AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
* OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/
#ifndef INC_ACCESSOR_H
#define INC_ACCESSOR_H
#include "intdefs.h"
#include "mem.h"
#if defined(__GNUC__) || defined(__clang__)
#define _ACCESSOR_UNUSED __attribute__((unused))
#else
#define _ACCESSOR_UNUSED
#endif
/*
* Defines a function to offset a pointer from a struct/class to a field based
* on a corresponding offset value off_<field>. Such an offset would be
* generally defined in gamedata. The function will be named getptr_<field>.
* Essentially allows easy access to an opaque thing contained with another
* opaque thing.
*/
#define DEF_PTR_ACCESSOR(type, field) \
_ACCESSOR_UNUSED static inline typeof(type) *getptr_##field(void *obj) { \
return mem_offset(obj, off_##field); \
}
/*
* Does the same as DEF_PTR_ACCESSOR, and also adds direct get/get functions.
* Requires that the field type is complete - that is, either scalar or a fully
* defined struct.
*/
#define DEF_ACCESSORS(type, field) \
DEF_PTR_ACCESSOR(type, field) \
_ACCESSOR_UNUSED static inline typeof(type) get_##field(const void *obj) { \
return *getptr_##field((void *)obj); \
} \
_ACCESSOR_UNUSED static inline void set_##field(const void *obj, \
typeof(type) val) { \
*getptr_##field((void *)obj) = val; \
}
/*
* Defines an array indexing function arrayidx_<class> which allows offsetting
* an opaque pointer by sz_<class> bytes. This size value would generally be
* defined in gamedata. Allows iterating over structs/classes with sizes that
* vary by game and are thus unknown at compile time.
*
* Note that idx is signed so this can also be used for relative pointer offsets
* in either direction.
*
* Note on performance: obviously doing n * size requires a multiplication by a
* global, which poses a bit of an optimisation challenge in loops. Based on
* some testing though it seems like this *should* usually be optimised into a
* single load of the global followed by repeated addition with no need for
* multiplication, given that we use LTO, so... don't worry about it! It's fine!
*/
#define DEF_ARRAYIDX_ACCESSOR(class) \
_ACCESSOR_UNUSED static inline struct class *arrayidx_##class(void *array, \
ssize idx) { \
return mem_offset(array, idx * sz_##class); \
}
#endif
// vi: sw=4 ts=4 noet tw=80 cc=80
|
