On Tue, Feb 20, 2018 at 02:26:49PM +0100, Martin Wilck wrote:
> This is a handy helper for creating one vector from another,
> mapping each element of the origin vector to an element of
> the target vector with a given conversion function. It can
> also be used to "concatenate" vectors by passing in a non-NULL first
> argument.
>
Reviewed-by: Benjamin Marzinski <bmarzins@xxxxxxxxxx>
> Signed-off-by: Martin Wilck <mwilck@xxxxxxxx>
> ---
> libmultipath/vector.h | 29 +++++++++++++++++++++++++++++
> 1 file changed, 29 insertions(+)
>
> diff --git a/libmultipath/vector.h b/libmultipath/vector.h
> index 3f6e579ae19a..6018b57525bf 100644
> --- a/libmultipath/vector.h
> +++ b/libmultipath/vector.h
> @@ -42,6 +42,35 @@ typedef struct _vector *vector;
> #define vector_foreach_slot_backwards(v,p,i) \
> for (i = VECTOR_SIZE(v); i > 0 && ((p) = (v)->slot[i-1]); i--)
>
> +#define identity(x) (x)
> +/*
> + * Given a vector vec with elements of given type,
> + * return a newly allocated vector with elements conv(e) for each element
> + * e in vec. "conv" may be a macro or a function.
> + * Use "identity" for a simple copy.
> + */
> +#define vector_convert(new, vec, type, conv) \
> + ({ \
> + const struct _vector *__v = (vec); \
> + vector __t = (new); \
> + type *__j; \
> + int __i; \
> + \
> + if (__t == NULL) \
> + __t = vector_alloc(); \
> + if (__t != NULL) { \
> + vector_foreach_slot(__v, __j, __i) { \
> + if (vector_alloc_slot(__t) == NULL) { \
> + vector_free(__t); \
> + __t = NULL; \
> + break; \
> + } \
> + vector_set_slot(__t, conv(__j)); \
> + } \
> + } \
> + __t; \
> + })
> +
> /* Prototypes */
> extern vector vector_alloc(void);
> extern void *vector_alloc_slot(vector v);
> --
> 2.16.1
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