[vlc-devel] [PATCH] atomic: prevent overflow

[Romain Vimont]

LGTM

But maybe uintmax_t is more appropriate than uintptr_t (semantically).

On 2/24/20 9:33 AM, quentin.chateau at deepskycorp.com wrote:
> From: Quentin Chateau <quentin.chateau at deepskycorp.com>
> 
> ---
>   include/vlc_atomic.h | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/include/vlc_atomic.h b/include/vlc_atomic.h
> index e2d4fe5360..625738849a 100644
> --- a/include/vlc_atomic.h
> +++ b/include/vlc_atomic.h
> @@ -60,7 +60,7 @@ static inline void vlc_atomic_store_float(vlc_atomic_float *atom, float f)
>   }
>   
>   typedef struct vlc_atomic_rc_t {
> -    atomic_uint refs;
> +    atomic_uintptr_t refs;
>   } vlc_atomic_rc_t;
>   
>   /** Init the RC to 1 */
> @@ -72,7 +72,7 @@ static inline void vlc_atomic_rc_init(vlc_atomic_rc_t *rc)
>   /** Increment the RC */
>   static inline void vlc_atomic_rc_inc(vlc_atomic_rc_t *rc)
>   {
> -    unsigned prev = atomic_fetch_add_explicit(&rc->refs, 1, memory_order_relaxed);
> +    uintptr_t prev = atomic_fetch_add_explicit(&rc->refs, 1, memory_order_relaxed);
>       vlc_assert(prev);
>       VLC_UNUSED(prev);
>   }
> @@ -80,7 +80,7 @@ static inline void vlc_atomic_rc_inc(vlc_atomic_rc_t *rc)
>   /** Decrement the RC and return true if it reaches 0 */
>   static inline bool vlc_atomic_rc_dec(vlc_atomic_rc_t *rc)
>   {
> -    unsigned prev = atomic_fetch_sub_explicit(&rc->refs, 1, memory_order_acq_rel);
> +    uintptr_t prev = atomic_fetch_sub_explicit(&rc->refs, 1, memory_order_acq_rel);
>       vlc_assert(prev);
>       return prev == 1;
>   }
>