[Tarantool-patches] [PATCH small 1/1] region: new region_alloc_array, updated alloc_object

[Vladislav Shpilevoy]

Still need 2 reviews here.

On 21/05/2020 22:32, Vladislav Shpilevoy wrote:
> Region's API provided a macro for aligned allocation of an object:
> region_alloc_object(). But not less frequent there is a case when
> need to allocate an array of objects, also aligned. The patch adds
> region_alloc_array() for that.
> 
> Also the patch adds an out parameter 'size' for both macros. It
> simplifies total size calculation, which is needed almost always,
> because total size is included into an error message, if the
> allocation fails.
> 
> Needed for https://github.com/tarantool/tarantool/issues/4609
> ---
> Branch: http://github.com/tarantool/small/tree/gerold103/region_alloc_array
> Issue: https://github.com/tarantool/tarantool/issues/4609
> 
>  small/region.h | 15 ++++++++++-----
>  1 file changed, 10 insertions(+), 5 deletions(-)
> 
> diff --git a/small/region.h b/small/region.h
> index bea88c6..df6567d 100644
> --- a/small/region.h
> +++ b/small/region.h
> @@ -386,10 +386,15 @@ struct RegionGuard {
>  };
>  #endif /* __cplusplus */
>  
> -#define region_reserve_object(region, T) \
> -	(T *)region_aligned_reserve((region), sizeof(T), alignof(T))
> -
> -#define region_alloc_object(region, T) \
> -	(T *)region_aligned_alloc((region), sizeof(T), alignof(T))
> +#define region_alloc_object(region, T, size) ({					\
> +	*(size) = sizeof(T);							\
> +	(T *)region_aligned_alloc((region), sizeof(T), alignof(T));		\
> +})
> +
> +#define region_alloc_array(region, T, count, size) ({				\
> +	int _tmp_ = sizeof(T) * (count);					\
> +	*(size) = _tmp_;							\
> +	(T *)region_aligned_alloc((region), _tmp_, alignof(T));			\
> +})
>  
>  #endif /* INCLUDES_TARANTOOL_SMALL_REGION_H */
>