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author | Emma Miler <emma.pi@protonmail.com> | 2022-12-19 19:32:16 +0100 |
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committer | GitHub <noreply@github.com> | 2022-12-19 19:32:16 +0100 |
commit | e04f3b36accccb590a2d51b4829256b9964ac3fd (patch) | |
tree | 20ee30c82e6f53e6e772be2e1b9613eebca12bf3 /NorthstarDLL/core/structs.h | |
parent | 33f18a735986dcd136bf8ba70ad8331306c28227 (diff) | |
download | NorthstarLauncher-e04f3b36accccb590a2d51b4829256b9964ac3fd.tar.gz NorthstarLauncher-e04f3b36accccb590a2d51b4829256b9964ac3fd.zip |
Restructuring (#365)
* Remove launcher proxy
* Restructuring
* More restructuring
* Fix include dirs
* Fix merge
* Remove clang thing
* Filters
* Oops
Diffstat (limited to 'NorthstarDLL/core/structs.h')
-rw-r--r-- | NorthstarDLL/core/structs.h | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/NorthstarDLL/core/structs.h b/NorthstarDLL/core/structs.h new file mode 100644 index 00000000..ac29f711 --- /dev/null +++ b/NorthstarDLL/core/structs.h @@ -0,0 +1,62 @@ +#pragma once +//clang-format off +// About this file: +// This file contains several macros used to define reversed structs +// The reason we use these macros is to make it easier to update existing structs +// when new fields are reversed +// This means we dont have to manually add padding, and recalculate when updating + +// Technical note: +// While functionally, these structs act like a regular struct, they are actually +// defined as unions with anonymous structs in them. +// This means that each field is essentially an offset into a union. +// We acknowledge that this goes against C++'s active-member guideline for unions +// However, this is not such a big deal here as these structs will not be constructed + +// Usage: +// To use these macros, define a struct like so: +/* +OFFSET_STRUCT(Name) +{ + STRUCT_SIZE(0x100) // Total in-memory struct size + FIELD(0x0, int field) // offset, signature +} +*/ + +#define OFFSET_STRUCT(name) union name +#define STRUCT_SIZE(size) char __size[size]; +#define STRUCT_FIELD_OFFSET(offset, signature) \ + struct \ + { \ + char CONCAT2(pad, __LINE__)[offset]; \ + signature; \ + }; + +// Special case for a 0-offset field +#define STRUCT_FIELD_NOOFFSET(offset, signature) signature; + +// Based on: https://stackoverflow.com/questions/11632219/c-preprocessor-macro-specialisation-based-on-an-argument +// Yes, this is hacky, but it works quite well actually +// This basically makes sure that when the offset is 0x0, no padding field gets generated +#define OFFSET_0x0 () + +#define IIF(c) CONCAT2(IIF_, c) +#define IIF_0(t, ...) __VA_ARGS__ +#define IIF_1(t, ...) t + +#define PROBE(x) x, 1 +#define MSVC_VA_ARGS_WORKAROUND(define, args) define args +#define CHECK(...) MSVC_VA_ARGS_WORKAROUND(CHECK_N, (__VA_ARGS__, 0)) +#define DO_PROBE(offset) PROBE_PROXY(OFFSET_##offset) // concatenate prefix with offset +#define PROBE_PROXY(...) PROBE_PRIMITIVE(__VA_ARGS__) // expand arguments +#define PROBE_PRIMITIVE(x) PROBE_COMBINE_##x // merge +#define PROBE_COMBINE_(...) PROBE(~) // if merge successful, expand to probe + +#define CHECK_N(x, n, ...) n + +#define IS_0(offset) CHECK(DO_PROBE(offset)) + +#define FIELD(offset, signature) IIF(IS_0(offset))(STRUCT_FIELD_NOOFFSET, STRUCT_FIELD_OFFSET)(offset, signature) +#define FIELDS FIELD + +//clang-format on |