Add a macro for allocating and populating a shallow copy of an array.
It is intended to replace a sequence like this:

   ALLOC_ARRAY(dst, n);
   COPY_ARRAY(dst, src, n);

With the less repetitve:

   DUP_ARRAY(dst, src, n);

It checks whether the types of source and destination are compatible to
ensure the copy can be used safely.

An easier alternative would be to only consider the source and return
a void pointer, that could be used like this:

   dst = ARRAY_DUP(src, n);

That would be more versatile, as it could be used in declarations as
well.  Making it type-safe would require the use of typeof_unqual from
C23, though.

So use the safe and compatible variant for now.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
René Scharfe 2023-01-01 22:14:12 +01:00 коммит произвёл Junio C Hamano
Родитель 08e8c26665
Коммит d2ec87a684
1 изменённых файлов: 5 добавлений и 0 удалений

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@ -1115,6 +1115,11 @@ static inline void move_array(void *dst, const void *src, size_t n, size_t size)
memmove(dst, src, st_mult(size, n));
}
#define DUP_ARRAY(dst, src, n) do { \
size_t dup_array_n_ = (n); \
COPY_ARRAY(ALLOC_ARRAY((dst), dup_array_n_), (src), dup_array_n_); \
} while (0)
/*
* These functions help you allocate structs with flex arrays, and copy
* the data directly into the array. For example, if you had: