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@xxxxxx>
---
Why typeof_unqual and not just typeof? To remove const when duplicating
a const array.
git-compat-util.h | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/git-compat-util.h b/git-compat-util.h
index e81bb14fc9..44abb240ae 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -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:
--
2.39.0
